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Gill Sans Bold
Senior Science
Preliminary Course
Stage 6
Plants
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SSC.Prelim 43174
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Acknowledgments
This publication is copyright Learning Materials Production, Open Training and Education Network –
Distance Education, NSW Department of Education and Training, however it may contain material from
other sources which is not owned by Learning Materials Production. Learning Materials Production
would like to acknowledge the following people and organisations whose material has been used.
• Stage 6 Syllabus Senior Science Board of Studies NSW. Amended October 2002
• Messel, H. 1963 Science for High School Students, University of Sydney, Sydney
• National Parks and Wildlife Service (NPWS)
• Photographs courtesy of Calib Buster
To complete this module you will need the audio tape Plant
adaptations or access to the audio internet files at
www.lmpc.edu.au/science, go to Senior Science then Plants
All reasonable efforts have been made to obtain copyright permissions. All claims will be settled in
good faith.
Writer:
Shelly Hudson
Editor:
Julie Haeusler
Illustrator:
Tom Brown
Revision:
Richard Alliband
Consultants:
Jenny Glen, Rhonda Caddy, Jane West
Copyright in this material is reserved to the Crown in the right of the State of New South Wales.
Reproduction or transmittal in whole, or in part, other than in accordance with provisions of the
Copyright Act, is prohibited without the written authority of Learning Materials Production.
© Learning Materials Production, Open Training and Education Network – Distance Education,
NSW Department of Education and Training, 2000. Revised December 2002 51 Wentworth Rd.
Strathfield NSW 2135.
Contents
Module overview ....................................................................... iii
Resources............................................................................................ iv
Icons .....................................................................................................v
Glossary............................................................................................... vi
Part 1: Attributes of plants ................................................... 1-35
Part 2: Experiments............................................................. 1-22
Part 3: Germination and plant adaptations .......................... 1-45
Part 4: Plant requirements................................................... 1-30
Part 5: Biodiversity and propagation.................................... 1-34
Part 6: Seed storage and endangered species ................... 1-34
Student evaluation of module
Introduction
i
ii
Plants
Module overview
Welcome to the module, Plants.
Do you like doing experiments? Do you have a favourite flower or
vegetable you would like to grow? If so, you will enjoy this topic.
You will carry out a range of experiments, exercises and research in your
local area on seed germination, propagated plants, endangered plants and
plant adaptations.
This module incorporates 30 hours of study. It is divided into six parts.
You should spend at least five hours working on each part.
The glossary will help you understand the meaning of words in the
module. The first time a glossary word is introduced, it appears in bold
text. It is suggested you use a dictionary for words not appearing in the
glossary.
You will learn some new terms about plants, the structures of plants, and
what conditions are required for optimum growth in Part 1.
Part 2 involves you in two experiments, possibly lasting for the duration
of this module. May even go longer.
Part 3 focuses on seed germination and you will also learn about the
water requirements of three different plant types outlined on audio
tape/internet audio files.
In Part 4, you will investigate the requirements for plant growth and
examine irrigation in agriculture using cotton production as an example.
Propagation techniques, plant biodiversity and conservation legislation
are addressed in Part 5 by listening to audio tape/internet audio files.
Part 6 introduces the storage of genetic material and conserving
endangered species.
Enjoy the Plants module. You may find the knowledge you gain useful
when propagating, growing or caring for plants in future years.
Introduction
iii
Resources
You will need the following equipment to carry out activities and
experiments during the module. In most cases, you should have most of
the items listed around your home. If not, some items can be made
easily, with little expense.
Part 1
•
colouring pencils
•
pencil
•
scissors
•
eraser
•
glue
Part 2
•
up to ten seed trays
•
soil or sand
•
seed raising mix or
fertiliser
•
5 small containers such
as film containers with
lids
•
up to one hundred and
fifty seeds of the same
variety e.g pumpkin
•
thermometer
•
ruler
Optional resources:
•
data logger
•
computer spreadsheet or
data base program
•
computer graphing
program
Part 3
•
Plant adaptations audio
tape and tape player
OR internet access
Parts 3, 5 and 6 all require Internet access
iv
Plants
Icons
The following icons are used within this module. The meaning of each is
written beside it:
The hand icon means there is an activity for you to do. It may be an
experiment or you may make something.
The talk icon guides you to discuss a topic with others.
There are exercises at the end of each part for you to complete and send to
your teacher.
The headphone icon asks you to complete an activity while listening to an
audio tape/internet audio file.
The safety glass icon points out that care needs to be taken when carrying
out a task.
There are suggested answers for the following questions at the end of each
part.
The computer mouse icon refers to an Internet website you may wish to
visit for additional information.
Introduction
v
Glossary
The following glossary provides the scientific meaning for many of the
term used in this module, Plants.
The HSC examiner will expect you to understand the meaning of every
scientific term used. If you find a term that you do not understand, then
look it up in a scientific dictionary or ask your teacher for assistance.
vi
abrasion
breaking a seed coat by rubbing against a rough
surface
absorb
to take in
acid soils
soil with a pH less than 7
adaptation
characteristic of a species that assists its survival and
reproduction in the natural habitat
adaptive advantage
a genetic trait that aids the survival of a species in a
changed environment
agriculture
farming; the cultivation of land and the production of
animals; the endeavour related to the supply of food
and fibre
angiosperm
flowering plant; plant producing seeds surrounded by
an ovary
anther
the site of pollen production on a flower
asexual
reproduction involving a single organism
autotroph/
autotrophic organism
self-feeder; can obtain energy directly from sources
other than through ingestion eg from the sun;
photosynthetic organism
basic
pH of greater then 7
basic soil
soil with a pH greater than 7
biodiversity
the variety of life forms, the different plants, animals
and micro-organisms, the genes they contain and the
ecosystems they form
bore water
water from a natural underground source
Plants
Introduction
bud
compact, undeveloped shoot containing immature
leaves or flowers
bulb
rounded, modified shoots, sprouting leaves from the
top and roots from the base
canopy
referring to the leafy section of a tree
channel
water way; a long ditch transporting water from a
water body (eg dam) to paddocks for irrigation
cilia
hair-like protrusions through the cell membrane which
undulate, causing cell locomotion in some unicellular
organisms
clone
descendants produced vegetatively being of the same
genetic make-up as the parent; asexual reproduction
CMS
strategy to carry out a fair experiment: Change
something, Measure something else, keep everything
else the Same
compost
a mixture of organic matter used for fertilising land;
increases soil fertility (soil structure and nutrient level)
concentrated
in a strong or high quantity
controlled variable
variable that is kept constant to keep an experiment
fair
cross-pollination
male gamete in pollen fertilising the ovum of a flower
from a different plant
cuticle
a non-living coating over the surface of a leaf,
protecting the underlying cells from damage and
dehydration
cutting
breaking a seed coat with a sharp object; a piece of a
plant stem, root or leaf used to produce another plant
by vegetative reproduction
data
things known or results obtained from which
inferences or conclusions can be made
degradation
to lower land quality eg. by erosion, salinity
dehydration
the removal of water or moisture
denitrification
to change nitrates to nitrites and nitrogen gas
dependent variable
the variable which could be affected by manipulation
of the independent variable in a scientific experiment
desiccation
the physical removal of water from a substance
detrimental
severe impact; death
dilute
in a weak or low quantity
vii
viii
dissect
to cut apart and examine
dormancy
a period of time in the life of an organism where
physiological processes are at a minimum; period of
inactivity
dormant
term applied to seeds in storage before they germinate
drainage
allow water through
ecosystem
a community of organisms interacting including the
environment in which they live
emergence
to come through the surface of
endangered
in danger of becoming extinct
epicormic buds
a shoot or branch growing out from a dormant bud on
the trunk of a tree, usually as the result of damage to
the tree
epiphyte
a plant that grows on another plant but does not use it
for food or water eg staghorn
estuary
the mouth of a river, where its currents meet the ocean
fertile soil
soil containing a variety macronutrients and
micronutrients which aid plant growth and
development with good soil structure and texture for
plant growth
fertilise
the fusion of two gametes, sex cells, producing a
single cell (biology); add nutrients to the soil
(agriculture)
filament
supports the anther of a flower
first-hand
gathered or done by you, either individually or as part
of a team
fragmentation
breaking apart into pockets
friable
crumbled easily; refers to soil texture
furrows
long depressions between hills
gamete
sex cell
gate
opens to allow passage from one side to another; in
irrigation, allows water to pass from the channel to
another channel or head ditch
genetic
something determined by DNA (deoxyribose nucleic
acid) of genes rather than the environment
germinate
the sprouting of a seed to form a new plant; to begin
to grow
grafting
joining the scion of one plant to the stock of another
Plants
Introduction
greenhouse
clear glass or plastic structure for the cultivation and
storage of plants
greenhouse effect
higher temperature inside the greenhouse than the air
outside. Radiation from incoming heat is restricted
from leaving, causing the air inside the greenhouse to
heat up; The Earth experiences a similar problem as
methane, carbon dioxide and other gases restrict heat
from leaving the Earth’s atmosphere, causing it to
heat up
guard cell
crescent-shaped cells occurring in leaves, surrounding
a pore allowing gases to enter and gases and water to
leave
gymnosperm
non-flowering plant producing naked seeds eg. pine,
cypress
head ditch
a long channel for water storage in irrigation; tail
water dam
heat bed
a soil bed, subject to artificial heating; used to
promote seed germination
herbicide
a chemical used to kill or inhibit the growth of plants
hills
long mounds of dirt used in agriculture for crops such
as cotton and potatoes
horticulture
commercial cultivation of plants eg. fruits, vegetables,
nuts
hypothesis
(plural hypotheses)
idea or thought that makes a prediction
independent variable
the variable that is manipulated
inference
idea or thought resulting from your brain thinking
about an observation or observations
information
meaningful data
inoculate
coating a seed with a bacterium to promote
germination and growth
intensity
level of; strength
intertidal zone
area within an estuary experiencing changes in water
height over a twenty four hour period due to tidal
movements
Landcare
an organisation aiming to improve the state
Australia’s land, water and the ecosystems on the land
laser-levelled
ground that has been levelled to a particular height by
using a laser to mark the height
leaching
washing with water to remove soluble chemicals
ix
x
legislation
an enforceable law or a body of laws
legislative
legal, concerned with the law
legumes
a plant of the pea family, some having a symbiotic
nitrogen-fixing bacteria associated with their roots;
their seeds are rich in protein; examples include peas,
beans, lupins and lucerne
lignotuber
the woody, fire-resistant underground base of a plant
stem that stores nutrients and sprouts after old shoots
have been destroyed
lime
calcium oxide (builder’s or mortar lime) or calcium
carbonate (agricultural lime)
lime pelleting
coating a legume seed with lime after it’s been
inoculated with bacteria
lucerne
a legume; forage plant with bluish purple flowers eg
alfalfa
lupin
any legume genus
macronutrients
nutrients required by plants in large amounts
mangrove
a tree that grows in muddy estuaries in salty water; in
subtropical and tropical climates; has pneumatophores
(aerial roots)
meristematic tissue
actively dividing cells at the tip of a growing stem
micronutrients
nutrients required by plants in small amounts
microscopic
on a very small scale, usually requiring the use of a
microscope
misting
supplying tiny droplets of water regularly to keep the
soil and soil surface moist
mulch
matter eg. straw placed on soil surface to increase
fertility, retain moisture and reduce weeds.
multicellular
composed of many different specialised cells
neutral soil
soil with a pH of about 7
neutron probe
measures soil moisture
nitrates
a nitrogen atom, bound to three atoms of oxygen;
containing nitrate ion (NO3-)
node
part of a plant stem where leaves arise
nodulation
the development of rounded lumps on roots which
harbour nitrogen-fixing bacteria
non-vegetative
sexual reproduction of plants
Plants
Introduction
observation
noticing something about an environment using your
senses
organic compound
carbon-based compound except carbonates and
carbon dioxide
organisms
living things
orthodox
seeds which can be stored for years in a seed bank
and still germinate
ovary
contains the female ovum in a flower and is the site
for fertilisation
ovum (plural ova)
female sex cell of a flower
parameter
variable; the boundary surrounding a particular
experiment
parent stock
plant to be propagated vegetatively or nonvegetatively
perched
in an elevated position
percolate
a liquid passing through a porous body
pesticide
chemical used to kill insects or other pests
phloem
part of the vascular system of a plant that conducts
sap (containing any sugars), manufactured by
photosynthesis, around the plant
photosynthesis
the process by which plants make food using the
energy of sunlight, CO2 and H2O
photosynthetic algae
single-celled organism, producing its own food
plantlet
mini plant with roots, stem and leaves
pollen
part of flower containing male sex cell
pollination
The transfer of pollen to a stigma
present tense
language that only refers to the present moment as
opposed to the past or future
product
a substance produced during a chemical reaction,
appears on the right side of a chemical equation
propagate
to multiply plants from parent stock
pseudopodia
a temporary protrusion of the cell, aiding the
movement of some unicellular organisms
qualitative
concerned with quality such as colour, hot, smooth.
quantitative
concerned with quantity
rare
uncommon
xi
xii
reactants
the chemicals present at the start of a reaction, on the
left side of the chemical equation
recalcitrant
seeds unsuitable for storage in a seed bank
reflect
a wave bouncing off a substance (physics)
reliability
consistency of results
respiration
a chemical process that releases energy from food
rich soil
soil that is high in nutrients
root promoting
substance which encourages plant roots to develop
rootrot
the fungal and bacterial attack of plant roots; plant
disease
runner
a horizontal stem growing above the ground and
spreading by the developing new plants at the nodes
salinity
salt rising to the surface of a soil profile
scarification
to breaking a seed coat, allowing water to enter a
seed
scion
plant to be grafted onto a stock (root)
secateurs
cutting implement designed to cut plant stems; used
to prune
secondary
data or information obtained from a source instead of
first-hand
self-pollinate
pollen fertilising a flower from the same plant
setting pipe
the action of delivering water through rubber pipes
from a head ditch to a field
sever
cut off cleanly and remove
State Forests
an Australian timber-growing body
stem elongation
lengthening of the stem
stigma
sticky opening at the end of a style which catches
pollen
stock
plant to be grafted onto a scion (shoot)
stolon
a horizontal stem growing above the ground and
spreading by the developing new plants at the nodes
stomates
a pair of guard cells bound by a central pore whose
size is regulated by the level of water in the guard
cells; controls water loss from the leaf and regulates
gas exchange with the air
strike
take hold; form a viable root system
Plants
Introduction
style
tube, joining the stigma to the ovary on a flower
succulent
a fleshy, juicy plant
sucker
seedling derived from a plant’s roots
temperate
moderate in temperature
tillering
shoots growing from the base of a plant
tissue culture
plantlets are grown on nutrient medium from
meristematic tissue; method used to produce virusfree plants
transplant
removal of a plant from one place to plant it in
another
trellis
a lattice frame or structure
tropical
warm and humid area
tuber
under ground thickening of a stem, storing energy
turgid
full of water
unicellular
organism consisting of one cell only
urea
nitrogen based waste product of many animals; used
as a fertiliser
vacuum
a volume of space containing no particles
vacuum packaging
packaging in a sealed container with hardly any air
valid
giving effective results and worthwhile conclusions
validity
degree to which an experiment/investigation gives
effective results and worthwhile conclusions
variable
something which can vary in value
vegetation
plant matter
vegetative
propagation
asexual reproduction of plants
visible light
light detected by the human eye
warm temperate
moderate to warm temperature
white light
light consisting of the visible spectrum
Wollemi Pine
an Australian endangered pine tree found in NSW
xerophyte
a plant adapted to growing in regions with low water
supply eg cactus and baobab tree
xylem
part of the vascular tissue which conducts water from
the roots of the plants, up to the stem and leaves
xiii
Gill Sans Bold
Senior Science
Preliminary course
Stage 6
Plants
Part 1: Attributes of plants
2
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In
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Senior Science Stage 6 Preliminary Course
Water for living
Plants
•
Attributes of plants
•
Experiments
•
Germination and plant adaptations
•
Plant requirements
•
Biodiversity and propagation
•
Seed storage and endangered species
Humans at work
Local environment
Contents
Introduction ............................................................................... 2
Plant structure and function....................................................... 3
Plants are organisms ...........................................................................3
Tissues, organs and organ systems....................................................6
Plants and mineral nutrients.................................................... 11
Nutrient deficiency..............................................................................12
Plants and photosynthesis ...................................................... 14
Describing experimental work ...........................................................16
Van Helmont’s experiment.................................................................19
Summary................................................................................. 22
Appendix ................................................................................. 25
Suggested answers................................................................. 27
Exercises – Part 1 ................................................................... 35
Part 1: Attributes of plants
1
Introduction
In Part 1 you will revise plant structure and function. You’ll also find
out about the trace element and macromineral nutrients required by
plants and what role photosynthesis plays in the growth of plants.
In this part you will be given opportunities to learn to:
•
describe plants as autotrophic organisms
•
identify mineral nutrients requirements by plants as
–
trace elements
–
macrominerals.
In this part you will be given opportunities to:
•
gather information to describe van Helmont’s experiment and
discuss the validity of his conclusions.
Adapted from Senior Science Stage 6 Syllabus © Board of Studies NSW,
December 2002. The most up-to-date version can be found on the Board's
website at http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
2
Plants
Plant structure and function
Have you ever considered where your food comes from? Fruits and
vegetables come from plants, but what about meat, fats, dairy products
and junk food?
Meat comes from animals (mainly cattle, sheep and poultry) as do dairy
products and some fats. These animals eat plants. Junk foods are mainly
made up of fat, sugar and flour. Lipids (fats and oils) come from animals
or plants (eg. canola oil), while sugar and flour come from plants.
So you can see that plants are essential for our lives. They transform the
Sun’s energy into a form of energy able to fuel our bodies. The more we
know about the structure of plants and their functions, the more we can
improve on plant health, growth and yields.
Plants are organisms
You, your pets, the plants around your house and your friends are all
made up of cells. Cells are the smallest units of life. All living things are
made up of cells and all cells come from other cells. You came from
your mother’s and father’s cells. You are a living thing. All living
things are called organisms. Plants are organisms too.
Autotrophic organisms
Plants are autotrophic organisms. An autotroph is a ‘self–feeder’
it makes its own food by a process called photosynthesis.
Plants contain a green chemical called chlorophyll that is needed for
photosynthesis to occur. Chlorophyll is stored in parts of a plant cell
called chloroplasts. The chloroplasts use energy from sunlight to make
food using water (from the soil) and carbon dioxide (from the air).
Part 1: Attributes of plants
3
1
Colour all the chloroplasts green in the plant cell below.
cell membrane
chloroplast
cytoplasm
nucleus
cell wall
2
What do chloroplasts do?
______________________________________________________
______________________________________________________
______________________________________________________
3
What does the term autotroph mean? Give an example of an
autotrophic organism.
______________________________________________________
______________________________________________________
______________________________________________________
4
Are chloroplasts found in the roots, stem and leaves of plants?
Explain your answer.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
Check your answers.
Unicellular organisms
Some organisms are unicellular. This means that they are only made up
of one cell. The single cell exchanges gases with its environment, feeds
and gets rid of wastes as a single cell.
4
Plants
Here are some examples of unicellular organisms.
paramecium
diatom
euglena
amoeba
Microscopic unicellularorganisms.
Using the following information, circle the unicellular organisms in the
diagram above that photosynthesise (make their own food).
•
diatom – microscopic single celled photosynthetic algae, living in
groups or colonies
•
amoeba – single celled organism which moves by pseudopodia to
gain food
•
euglena – single celled photosynthetic algae
•
paramecium – microscopic single celled organism that moves with
cilia to find food
Check your answers.
Multicellular organisms
A multicellular organism is made up of different kinds of specialised
cells; each kind of cell has a particular role or function that benefits the
organism. Each cell in a multicellular organism is dependent on other
cells for its survival.
You are a multicellular organism. Do you think all your cells are
identical? Does a cell in your tongue do the same thing as a bone cell
in your leg? Do all your cells do the same things?
You have specialised cells in your lungs which absorb oxygen and
release carbon dioxide. Other cells in your stomach assist in the
digestion of food. Cells in your kidneys filter out wastes. Cells in your
heart work together to pump blood around your body. Cells in your
bones help you to stand up straight and move around.
As you can see, your body is made up of many different cells and each
kind has a different role. Most plants are multicellular organisms too.
Part 1: Attributes of plants
5
1
Define a unicellular organism and give an example.
_____________________________________________________
_____________________________________________________
2
Define a multicellular organism and give an example.
______________________________________________________
______________________________________________________
Check your answers.
Cells in multicellular organisms are organised so that the needs of
individual cells are met, and so that individual cells contribute to the
survival of the entire organism. Similar cells group together to form
tissue, different kinds of tissues form organs and different organs make
up organ systems.
Tissues, organs and organ systems
Read these definitions.
tissue
a group of cells of the same type with the same
function; for example, phloem
organ
part of an animal or plant forming a structural and
functional unit, which is made up of one or more
tissues; for example, a leaf
organ system
a group of organs that function together as a unit;
for example, the vascular system
The examples given above are all parts of multicellular plants.
You have tissues, organs and organ systems in your body too. What is an
example of a tissue in your body? Can you name an organ in your body?
Have you heard of the digestive system or the respiratory system?
These are examples of organ systems. An example of an organ is your
heart and an example of a tissue is smooth muscle.
6
Plants
organ system
(digestive system)
The digestive system is an organ system in humans.
organ
(heart)
tissue
(muscle)
Muscle is a type of human tissue; the heart is an organ.
This module deals with plants. So, in this module, focus on examples of
tissues, organs and organ systems in plants.
Part 1: Attributes of plants
7
1
Complete the table below about tissues, organs and organ systems.
Structure
Definition
Example
tissue
part of an animal or plant forming a
structural and functional unit, which is
made up of one or more tissues
vascular system
Plant cells require oxygen, glucose, water and carbon dioxide for growth
and development. Not every cell has direct access to all of these.
Other cells are responsible for transporting these materials to cells that
need them. For example, cells in the phloem transport food, as a sugar
called glucose, to cells throughout the plant. Guard cells in stomates are
responsible for supplying carbon dioxide to mesophyll cells inside leaves
so that photosynthesis can occur. Xylem vessels transport water from the
roots to all cells in the plant.
epidermis
cuticle
cells containing chloroplasts
palisade
mesophyll
tissue
spongy
mesophyll
tissue
stomate
vascular bundle
(xylem and phloem)
air space
cell wall
Leaf cross–section showing different cell and tissue types.
This diagram is adapted from Messel, H. 1963 Science for High School
Students, University of Sydney, Sydney
8
Plants
2
The cells in the diagram on the previous page can all be found in the
plant organ called a leaf.
a) Shade green the tissue in the leaf composed of mesophyll cells.
b) Shade red the vascular tissue made from xylem and phloem cells.
c) How many stomates can you see in the diagram?
3
Following are some examples of specialised cells in plants.
Next to each type of cell, write the function from the paragraph above.
sieve tube
a) phloem cell
sieve plate
pore in sieve plate
thin tube wall
b) guard cells in a stomate
guard cell
c) mesophyll cell
chloroplast
nucleus
cell wall
Check your answers.
Part 1: Attributes of plants
9
Roots, stems and leaves
The parts of the plant below the soil are often called the root system.
Parts above the ground – leaves, stems, buds and flowers are often called
the shoot system. The vascular system of a plant refers to xylem and
phloem vessels throughout the plant that transport water, dissolved
nutrients and minerals, and other chemicals. The term system refers to
a group of organs that works together to perform a particular role for
an organism.
3
1
Label the root
system and the shoot
system on the
following diagram
of a plant.
2
Cut out the
information on Plant
structures in the
‘Appendix’ at the
back of this part.
Stick each piece of
information in the
correct place on the
diagram.
Do flowering plants need to have roots, stems and leaves?
Explain your answer.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
Check your answers.
10
Plants
Plants and mineral nutrients
Plants need at least 16 nutrients to grow and develop. These nutrients are
absorbed through the roots from the soil. They can be divided into two groups:
•
macronutrients (or macrominerals or macroelements), such as
nitrogen, phosphorus and potassium, are needed in significant quantities
•
micronutrients or trace elements (or microelements), such as iron,
manganese and chlorine, are required in very small amounts.
1
The diagram below shows macronutrients and micronutrients being
applied to a garden. Complete the diagram using names of examples.
Macronutrients
Micronutrients
o
cr
m
i
trie
nu
mac
ro
nu
tri
en
ts
nts
Macro and micronutrients being applied to a garden.
2
Look at the names of the macro and micro nutrients above.
How are all these substances similar?
_____________________________________________________
Check your answers.
Part 1: Attributes of plants
11
Nutrient deficiency
What happens if plants do not have enough of the macronutrients and
trace elements they need? Plants show symptoms when they are
deficient (lacking) in certain macronutrients and micronutrients.
Their leaves may become discoloured, they may not grow as tall as usual,
the fruits may be spotted and so on. (You may have heard of or seen
plants with mildew, other diseases or pest infestations. These are
generally not directly related to soil nutrient deficiencies but sometimes
the symptoms are similar.)
1
The table below states some symptoms of mineral deficiency in
some plants. Draw a picture for each symptom. If you exaggerate
the drawing, you are more likely to remember when you observe
plant growth. Using coloured pencils may help you with exaggerating
the drawings. The first drawing has been done for you.
Plant symptoms
Cartoon drawing
Pear
Boron deficiency causes cracking of the
pear’s skin and stunting of the pear.
pear
Apple
Magnesium deficiency causes yellowing
of leaves and makes the outer edges of
leaves die and shrivel up.
Celery
Boron deficiency causes the stem to
crack and turn brown.
Capsicum
Over fertilising capsicum plants
produces large, leafy plants and no fruit.
12
Plants
2
If you live on a property or your family likes gardening, you may
know of different plant deficiency symptoms.
Describe a plant symptom that indicates nutrient deficiencies and
identify the type of plant and the lacking nutrient.
_____________________________________________________
_____________________________________________________
_____________________________________________________
3
If you were asked to provide an example of a plant and its symptoms
from the lack of a particular nutrient in a test, which example would
you give and why?
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
4
Look at the information on three different packets of plant fertiliser.
(You may have packs in a shed, or a friend or neighbour may have
some fertiliser. You could look at packs in a supermarket or
hardware store.)
What deficiencies have the fertilisers been developed to prevent?
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Now complete Exercise 1.1. You will need to use information
from the three packs of fertiliser in your answer.
Part 1: Attributes of plants
13
Plants and photosynthesis
Plants and photosynthesis are words that go together. Why?
A very important feature of plants is that they are autotrophic; that is,
they make their own food and they use the process of photosynthesis.
Here is the overall word equation for photosynthesis:
carbon dioxide + water
sunlight
chlorophyll
glucose + oxygen
The substances on the left of the arrow (carbon dioxide and water) go
into the plant; they are the reactants for photosynthesis. The substances
on the right of the arrow (glucose and oxygen) are the products formed
during photosynthesis.
For photosynthesis to occur, carbon dioxide must move from the air into
cells in the leaves. Water is absorbed through the roots and carried
through vascular tissue to the leaves. Then oxygen formed during
photosynthesis is released into the air. Glucose formed is used by the
plant as an energy source or converted into other chemicals for the plant.
1
Your body uses the food you eat for energy. Your body needs
this energy to think, walk around, grow, repair bruises and cuts and
many other things. What do you think plants use energy for?
List as many things as you can.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
14
Plants
2
Label the diagram below to show the substances involved in
photosynthesis that move in or out of the plant.
3
Where does photosynthesis occur in a plant?
_____________________________________________________
4
Where does a plant absorb water?
_____________________________________________________
5
What provides the energy for photosynthesis?
_____________________________________________________
6
What does a plant make during photosynthesis that makes it
autotrophic (self–feeding)?
_____________________________________________________
Check your answers.
Part 1: Attributes of plants
15
Describing experimental work
This section revises some of the important concepts developed in the
Stage 4–5 Science course.
Observations
Observations are made using the senses of sight, touch, hearing, smell
and (only under strictly controlled conditions in experimental work)
taste. It is important that you protect your senses from hazardous
conditions by, for example:
•
wearing protective glasses or goggles
•
not touching hot or very cold surfaces with bare skin
•
avoiding loud sounds or explosions
•
filling lungs with air and smelling cautiously by taking small sniffs
followed by breathing out.
Your sense of taste is useful in making observations about food but
should not be used with laboratory chemicals. Many chemists in the
1800s died or became seriously ill because taste was one of the properties
that they used to describe newly made chemicals.
Observations can be:
•
qualitative, concerned with the quality such as green, hot or loud
•
quantitative, involving a measurement such as 25°C or mass change
of 64 g.
Inferences
An observation is made by sense organs sending information to your
brain. An inference is an idea or thought resulting from your brain
thinking about an observation or observations.
If you walked into a room and found liquid on the floor your thinking
brain could come up with a range of inferences such as:
•
the roof is leaking rainwater
•
someone has spilt soft drink
•
a dog has urinated.
Further observations may be needed to decide between these inferences.
16
Plants
Hypotheses
A hypothesis (plural hypotheses) is an idea or thought that makes a
prediction. You may be able to test a hypothesis by carrying out a
first–hand investigation or by checking it against information from
secondary sources.
Hypotheses can be easier to test if they are worded as a researchable
question such as ‘What happens to plant seedling growth when light
intensity is increased?’
Variables
Any quantity that can vary is a variable.
If you were carrying out an experiment on the effect of light intensity on
growth rate of plant seedlings you would try to control many variables
such as type of plant, type of soil, amount of water and size of the
container. The factors that you try to keep constant are called controlled
variables. You are trying to make your experiment a fair experiment.
The one quantity that you change, in this case light intensity, is called the
independent variable.
The quantity that you measure to see how it is affected by the changing
independent variable is called the dependent variable. For this case the
height of the seedling could be the independent variable.
To carry out a fair test a recommended strategy is CMS.
Change something, Measure something else and keep everything else
the Same. Match each of the three CMS features with the three types of
variables by drawing lines between the two columns of the table below.
CMS feature
Type of variable
Change something
controlled
Measure something else
independent
keep everything else the Same
dependent
Check your answers.
Part 1: Attributes of plants
17
Data and information
Data such as 0111 can be gathered during experimental work. If you find
the data is meaningful, realising that 0111 could be binary code for the
number 7, then it is called information. Information is meaningful data.
First–hand data and information is gathered by you, individually or as
part of a team, normally by carrying out an experiment or investigation.
Secondary data and information is obtained from another source such as
the Internet or books.
Reliability
Reliability refers to consistency of results. Reliable experimental work
can be repeated many times giving similar results.
Reliable sources of information are consistent with information obtained
from other reputable sources. The greater the number of reputable
sources that agree, the more reliable your information should be.
When searching the Internet the address of a web site will give you some
idea of how reputable a source could be – .edu indicates an educational
establishment, .gov a government department, .org a non–profit
organisation and .com a commercial, for profit, organisation.
Validity
Validity depends on whether the results obtained are caused by the factor
you are changing, the independent variable. If you came up with the
hypothesis that increased light intensity increases seedling growth then
further investigation may find this happens for the low light intensities
that you first used but not for high light intensities. Your original
hypothesis would not be valid. The original hypothesis would need to be
modified then tested again.
The validity of secondary information and data depends on how the
information was gathered. It is very easy to get biased results if a group
of people surveyed is not a random sample.
A valid experiment tests your hypothesis, enabling you to draw
worthwhile conclusions about the correctness of your hypothesis.
Measurements can be reliable (giving consistent results) without being
valid (that is, not caused by the phenomena you are interested in).
However, measurements cannot be valid unless they are at least reliable.
18
Plants
Review your knowledge and understanding of ways of describing
experimental work by drawing connecting lines between the parts of the
two columns.
Concept
Definition
observations
involving a measurement
quantitative observation
factor that is kept constant in an
experiment
inference
giving consistent results
controlled variable
made through sense organ connections
to the brain
information
leading to worthwhile conclusions about
the phenomenon you are investigating
first–hand
meaningful data
secondary
result of brain thinking about an
observation or observations
reliable
resulting from hands–on activity
valid
source of results produced by others, not
yourself
Van Helmont’s experiment
Johann Baptist van Helmont lived in Belgium and his quantitative
findings for growth of a willow tree were reported in 1648. He carried
out a significant experiment, providing evidence that was used in the
development of the idea of photosynthesis.
For two thousand years from the time of the Ancient Greeks until the
results of van Helmont’s experiment became well known, it was believed
that plants were a combination of earth and fire. Plants grew out of the
earth and when burnt they released fire. Van Helmont hypothesised that
water, not earth, was responsible for the growth of plants.
Part 1: Attributes of plants
19
Use Internet access to gather information to describe van Helmont’s
experiment. You can find some links at the www.lmpc.edu.au web site.
Using a search engine such as www.google.com you should be able to find
additional web sites. If you do not have Internet access seek out information
from books and encyclopedias in a library.
Read the information that is available to you, make brief notes in the
space below, then answer the questions that follow.
1
What do you think was the aim of van Helmont’s experiment?
_____________________________________________________
_____________________________________________________
2
Did the soil’s weight change much over the five years?
______________________________________________________
3
By how much did the plant’s weight increase?
______________________________________________________
4
Do you think the plant gained its weight from the soil only?
Why? Why not?
______________________________________________________
______________________________________________________
______________________________________________________
20
Plants
5
What was van Helmont’s conclusion?
_____________________________________________________
_____________________________________________________
6
Do plants need to consume food as animals do?
_____________________________________________________
7
Where do plants get their energy from?
_____________________________________________________
8
As humans grow into adults, they gain weight. Plants gain weight
too. Use the equation for photosynthesis to help explain where the
increasing plant weight comes from.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
9
Think about how van Helmont conducted his experiment. Based on
his experiment, do you think his conclusion was valid? Explain.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Check your answers.
In the next section, you will be completing a crossword summary of
Part 1. While completing the task, you may find you have learned more
than you thought.
Part 1: Attributes of plants
21
Summary
Complete the crossword below using the clues on the following page.
1
2
4
3
6
5
7
L
8
9
11
10
12
13
14
27
15
C
16
17
18
19
20
21
22
23
24
25
26
27
28
22
Plants
Across
Down
1
An element required by plants that
starts with ‘p’
2
A gas produced during
photosynthesis
5
A group of cells of the same type
with the same function
3
Where plants obtain their mineral
nutrients
7
Most are examples of multicellular
organisms
4
Vessels that transport water up the
stem to cells in the leaves
8
Type of energy used by plants for
photosynthesis
6
Organisms made up of one cell
only
9
A single–celled autotroph starting
with ‘d’
10 A group of organs that function
together as a unit
14 Supports the plant’s leaves and
flowers while transporting water
and nutrients
17 Absorb water and nutrients for
the plant
20 An example of an organ system in
a flowering plant
22 An example of a micronutrient
24 A ‘self–feeder’, that makes its
own food
25 The ripened ovaries (of flowers)
with fertilised seeds
26 Organism made up of different
kinds of specialised cells are called
_______________________
28 A structure in a cell, where
photosynthesis occurs
(It contains chlorophyll)
11 Plants need a lot of these to
grow well
12 Something required by plants in
very small amounts
13 A macronutrient starting with ‘n’
15 The process by which a plant
makes food is called
_______________________
16 A gas absorbed through leaves that
is needed for photosynthesis
18 Edible parts of plants that do not
contain seeds
19 All living things are called
_______________________
21 Vessels that transport sugar, such
as glucose, around the plant
23 Part of a multicellular plant which
is made up of one or more tissues
and is a structural and functional
unit
27 An example of a plant organ
Part 1: Attributes of plants
23
24
Plants
Appendix
Plant structure and function
Roots
Anchor the plant firmly
in the soil and allow the
plant to absorb water
and nutrient minerals
Part 1: Attributes of plants
Stems
Support the leaves and
flowers. Also transport
water and nutrients
between the roots and
leaves
Leaves
The site of photosynthesis,
where sunlight is used to
make glucose from carbon
dioxide and water, and so
the plant obtains energy
25
26
Plants
Suggested answers
Autotrophic organisms
1
The chloroplasts are the small oval shaped structures inside the
plant cell. There are ten chloroplasts in the diagram that you should
have shaded. (You have coloured them green because they contain a
green chemical called chlorophyll.)
2
Chloroplasts carry out photosynthesis.
(You could also answer that chloroplasts contain chlorophyll, which is
necessary for photosynthesis.)
3
An autotroph is a self–feeder (or an organism that makes its own
food). A plant is an example of an autotroph.
4
Chloroplasts are in the leaves as chloroplasts are green and leaves
are green. Chloroplasts have to be in leaves so that they can be in
sunlight to make food for the plant. They can also be found in green
stem cells. They are not found in roots because cells in the roots
would be underground and would not receive sunlight and so could
not carry out photosynthesis.
Unicellular organisms
paramecium
diatom
euglena
amoeba
The diatom and euglena photosynthesise.
Part 1: Attributes of plants
27
Multicellular and organisms
1
A unicellular organism is made up of one cell only. Examples
include diatoms, some algae, amoeba, euglena and paramecium.
2
A multicellular organism is made up of different kinds of specialised
cells. Flowering plants or most animals are examples of
multicellular organisms.
Tissues, organs and organ systems
1
Here are some sample answers.
Structure
2
Definition
Example
tissue
a group of cells of the same type with the
same function
phloem
organ
part of an animal or plant forming a
structural and functional unit, which is
made up of one or more tissues
leaf
organ system
a group of organs that function together
as a unit
vascular system
a) You should have shaded green all the cells in the palisade
mesophyll and spongy mesophyll tissue. (You can see the dots
for the chloroplasts drawn in these cells.)
b) You should have shaded red the tubes that make up the vascular
bundle. These are the xylem and phloem vessels.
c) There is one complete stomate and two cut stomates – three
separate stomates. (There is part of one of the cut stomates in
the thin layer of leaf peeled off to the right of the diagram, so an
answer of three or four is acceptable.)
3
a) Phloem cells transport glucose in water solution to cells
throughout the plant.
b) Guard cells change shape to open and close the stomate, and so
control the supply of carbon dioxide to cells within the leaf (and
prevent excessive loss of water).
c) Mesophyll cells carry out photosynthesis, converting light
energy into chemical energy stored within the plant.
28
Plants
Roots, stems and leaves
1,2
Leaves
The site of photosynthesis,
where sunlight is used to
make glucose from carbon
dioxide and water, and so
the plant obtains energy
Stems
Support the leaves and
flowers. Also transport
water and nutrients
between the roots and
leaves
shoot system
root system
Roots
Anchor the plant firmly
in the soil and allow the
plant to absorb water
and nutrient minerals
3
Flowering plants need all their organs and organ systems because
each has its own role to perform in maintaining the plant as a
functioning organism. For example, the plant could not function
without roots because it would be unable to obtain water and mineral
nutrients. It could not function without leaves because they are the
site for photosynthesis.
Part 1: Attributes of plants
29
Plants and mineral nutrients
Macronutrients
Micronutrients
nitrogen
iron
phosphorus
manganese
potassium
chlorine
o
cr
m
i
trie
nu
mac
ro
nu
tri
en
ts
nts
2
All the macronutrients and micronutrients listed are elements.
Plants and photosynthesis
1
Plants need energy to grow, repair damaged tissue, transport
materials around the plant and for reproduction.
2
oxygen
carbon dioxide
water
30
Plants
3
Photosynthesis occurs in the leaves of plants. (It can also occur in other
green parts, such as soft stems.)
4
Plants absorb water through the roots.
5
Sunlight provides energy for photosynthesis.
6
Plants produce glucose (and oxygen) during photosynthesis.
Glucose is the source of chemical energy for the plant and used to
make the chemicals it needs to grow and function.
Describing experimental work
CMS feature
Type of variable
Change something
independent
Measure something else
dependent
keep everything else the Same
controlled
Concept
Definition
observations
made through sense organ connections
to the brain
quantitative observation
involving a measurement
inference
result of brain thinking about an
observation or observations
controlled variable
factor that is kept constant in an
experiment
information
meaningful data
first–hand
resulting from hands–on activity
secondary
source of results produced by others, not
yourself
reliable
giving consistent results
valid
leading to worthwhile conclusions about
the phenomenon you are investigating
Part 1: Attributes of plants
31
Van Helmont’s experiment
32
1
To test his hypothesis that water was responsible for the growth of
plants.
2
No. The soil’s weight decreased by about three ounces (80 g) over
the five years.
3
The plant’s weight increased by about 169 pounds (77 kg).
4
The plant could not have gained its weight from the soil only.
The soil’s weight only decreased by a small amount (about 80 g)
while the plant’s weight increased by a larger amount (about 77 kg).
5
Plants gain weight from water only.
6
No, plants make their own food. They are autotrophic.
7
Plants obtain energy from sunlight.
8
Plants gain weight from carbon dioxide and water which combine to
form glucose (and oxygen). Glucose is a carbon compound and is
used for energy and growth. Growth produces new substances that
add weight to the plant.
9
Van Helmont’s conclusion is not valid as it is based on his results for
one plant only. To be valid an experiment must be reliable, giving
consistent results when repeated. Van Helmont should have
repeated his experiment by growing several plants or different kinds
of plants, not just one. His conclusion that plant growth came from
water alone was also not valid as the experiment did not control
other variables such as gases that could have contributed to plant
growth.
Plants
Summary
1
2
Part 1: Attributes of plants
4
3
S P H O R U S
O
5
6
T I S S U
H T
L
N
9
D I
C
13
14
N
S T E
16
I
L
C
T S
L
A
19
R
O
U
R
O
B
R
L
G
O
G
A
20
E
N
A
R
N
D
N
22
I
I R O
O
S
X
M
25
P H
I
S
F
D
27
U L T I C E L L U L
E
28
C H L O R O P L A S T
F
P H O
X
Y
8
L I G
E
11
12
M
M
N
A
I
C
C
17
R
R O O
O
O
N
N
U
U
T
T
R
R
21
I
I
P
E
E
H
N
N
L
24
A U T O T R O
S
S
E
26
M
E
A
M
O
N
23
O
R
G
A
N
X
Y
7
P LL A N T S
E
10
T O M
R
27
15
G
C
P
A
H
18
N
O
V
S
T
E
Y
O
G
T
S
E
O T S Y S T E M
E
N
A
M
T
B
H
L
E
E
U I T S
S
I
R
S
33
34
Plants
Exercises - Part 1
Exercises 1.1
Name: _________________________________
Exercise 1.1
Fertilisers are produced in many different forms. Look at the packets of
any three fertilisers and record the components. The nutrients may be
named as the actual compounds in the fertiliser or as the elements that
plants can obtain from it. Name the fertiliser then its components.
i)
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
ii)
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
iii) _____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 1: Attributes of plants
35
Senior Science
Preliminary course
Stage 6
Plants
Part 2: Experiments
2
0
0
I
2
r
be S
o
t
c NT
O
ng DM E
i
t
ra E N
o
rp A M
o
nc
Gill Sans Bold
Senior Science Stage 6 Preliminary Course
Water for living
Plants
•
Attributes of plants
•
Experiments
•
Germination and plant adaptations
•
Plant requirements
•
Biodiversity and propagation
•
Seed storage and endangered species
Humans at Work
Local Environment
Part 2: Experiments
1
Gill Sans Bold
Contents
Introduction ............................................................................... 2
Experiments .............................................................................. 4
Experimental report..............................................................................4
1 Temperature and seed germination ....................................... 6
Sample experiment ..............................................................................7
2 Crowding of seedlings .......................................................... 10
Summary................................................................................. 12
Appendix ................................................................................. 13
Bob’s experiment................................................................................13
Suggested answers................................................................. 15
Exercises – Part 2 ................................................................... 17
Part 2: Experiments
1
Introduction
This part focuses on the growth of plants. You will be observing the
effect on seed germination and seedling growth of various factors.
Plant experiments take time to show results. Setting up these
experiments now will allow you to observe your plants growing while
you carry out other activities within the module.
In this part you will be given opportunities to learn to:
•
explain the effects of one of the following on seedling growth:
–
temperature
–
moisture
–
water quality
–
crowding of seedlings.
In this part you will be given opportunities to:
•
•
2
plan, choose equipment and resources for, and perform a first–hand
investigation to:
–
design and perform a set of controlled experiments to
investigate the effect of either a range of temperatures, moisture
levels or oxygen supply on the germination rate of a seed
–
use appropriate data loggers and probes to monitor either
temperature, humidity or oxygen levels in experimental
conditions
–
gather analyse and present findings in an appropriate form
plan, choose equipment and resources for, and perform a first–hand
investigation and present findings in an appropriate manner to
explain the effect of one of the following variables on plant growth:
–
temperature
–
moisture
–
light intensity
–
water quality
Plants
Gill Sans Bold
–
•
crowding of seedlings
process information to graph and identify the importance of one
named factor on seedling growth.
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
December 2002. The most up-to-date version can be found on the Board's
website at http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
Part 2: Experiments
3
Experiments
You should be familiar with the structure and language of an
experimental report in science. What experiments did you complete in
the last module? Did each have a purpose and a list of equipment needed
to complete the activity? Did each have a method, outlining how the
experiment should be conducted? Did each have a place to record the
results? Did each require you to make a conclusion based on the results?
Experimental report
Every experimental report has a similar structure. Many scientists use a
similar structure to the one below to record their experiments.
4
Aim
This states what you are trying to find out.
Apparatus
This states what you will use to carry out the
experiment.
Method
This outlines how you will do the experiment and may
include a labelled diagram.
Results
Here you record your observations. Often results are
recorded in a table. Graphs and diagrams may be
included.
Conclusion
This states what you found out from your observations.
The conclusion always answers your aim.
Plants
Gill Sans Bold
There are three important considerations when you are doing
experiments:
•
In every experiment you should change only one variable. This is called
the independent variable. You make observations of the variable that
depends on the independent variable. The variable that you observe is
called the dependent variable. All the other variables should be kept the
same, or constant. These are called the controlled variables.
For example, an experiment was planned to investigate how plant
height was affected by temperature. Trials were set up with the
same size pot, species of seed, amount of soil, soil type, amount of
water but different temperatures. Temperature was the factor that
you chose to vary, making it the independent variable. Any changes
in the dependent variable, the height, are therefore likely to be due to
differences in temperature.
•
Every experiment should have a control, if possible. A control is the
trial with which you can compare the factor you are testing. The trial
conditions are usually normal.
For example, in the previous experiment, the control had the same
size pot, the same species of seed, the same amount of soil, the same
soil type, the same amount of water and was set up at normal room
temperature. Results from the pots at different temperatures would
be compared to the control at normal temperature.
Another example would be an experiment where 10 seeds were
placed in 10 mL of oil; 10 seeds placed in 10 mL of water; and 10
seeds in air. Here, the seeds in the water and oil will be compared to
the ones in the air, which was the control.
•
Scientific writing always states facts and observations without
referring to the observer (you). The present tense is usually used.
The main exception is in describing what was done in the method
where past tense can be used. Refer to the Science Resource Book
for guidance with scientific writing.
Remember to use scientific writing when you are reporting
observations and conclusions.
Part 2: Experiments
5
1 Temperature and seed germination
Have you ever grown a plant from seed before? If so, what type of plant
was it? Is it still alive?
You may know what a seed looks like when it sprouts or germinates.
You may even remember information about seed germination from other
studies of science or agriculture.
Part 3 of this module contains more detail about seed germination.
Starting this experiment now allows you to observe seed germination
while you carry out other germination activities in Part 3.
Temperature, the amount of water and oxygen can all affect the
germination rate of seeds. You will be designing an experiment to
determine the effect temperature has on the germination rate of seeds.
You are required to:
•
design and perform a set of controlled experiments to investigate the
effects of a range of temperatures on the germination rate of a seed
•
monitor temperatures using data loggers and probes
•
gather, analyse and present findings in an appropriate form
If you are completing this module in a school, you may have access to
data loggers and graphing programs. You should have experience using
this equipment. Therefore, you must include them in the design of your
experiment. If you don’t have access to such equipment, you should
record your results in an appropriate table then graph them using
graph paper.
An example of an experiment that Lynette designed is on the next page.
Lynette had access to a computer graphing package but not a data logger.
Lynette was careful with the packaged pumpkin seeds as they were coated
with a poisonous fungicide. She washed her hands well after handling them.
6
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Sample experiment
Aim
This experiment will determine the effect of temperature on
the germination rate of seeds.
Apparatus
•
five small, dark film containers with lids
•
pumpkin seeds
•
thermometer.
1
Half fill each of the five containers with water.
2
Place 10 seeds in each container.
3
Place one container in the cold refrigerator.
4
Place one container in a cool place (bathroom cupboard).
5
Place one container in a place at room temperature
(bedroom).
6
Place one container in a warm place (kitchen window
sill).
7
Place one container in a fairly hot place (next to the sunny
garage wall).
8
Record the temperature of the water the seeds are in at the
same time each day (9 am).
9
Check the number of seeds that have sprouted a root in
each container daily. When half or more have sprouted,
record the day.
Method
10 Draw a line graph showing the daily temperatures for
each of the seeds over 10 days.
Results
Seeds
cold
–
cool
day 9
room temp.
day 4
warm
day 2
hot
Part 2: Experiments
The day when more than half
the seeds germinated
–
7
Temperature (°C)
Conditions
Day
1
Day
2
Day
3
Day
4
Day
5
Day
6
Day
7
Day
8
Day
9
Day
10
Average
temp. °C
cold
4
4
4
4
5
4
4
4
4
4
4
cool
12
13
15
15
12
11
12
13
14
13
13
room
temperature
21
25
23
23
20
19
24
25
22
21
22
warm
29
28
30
31
30
31
30
29
28
32
30
hot
38
42
44
42
43
39
40
40
39
42
41
45
hot
40
Temperature (∞C)
35
warm
30
25
room
temp
20
15
cool
10
5
0
Conclusion
1
cold
1
2
3
4
5
Day
6
7
8
9
10
(Refer to the previous page to answer questions 1 and 2).
At which temperatures did the pumpkin seeds germinate best?
______________________________________________________
2
At which temperatures did seeds germinate poorly?
______________________________________________________
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3
What was the control for this experiment?
_____________________________________________________
_____________________________________________________
4
What was the only thing you changed during the experiment (the
independent variable)?
_____________________________________________________
_____________________________________________________
5
How could you improve the experiment?
_____________________________________________________
_____________________________________________________
Check your answers.
Now you are ready to design your own experiment. Your aim is to
determine the effect temperature has on the germination rate of seeds.
Remember, you are required to:
•
design and perform a set of controlled experiments to investigate the
effects of a range of temperatures on the germination rate of a seed
•
use appropriate data loggers and probes to monitor temperatures in
experimental conditions
•
gather, analyse and present findings in an appropriate form.
Use the guidelines below to draft your experimental design on your own
paper.
Aim
What is the purpose of the experiment?
Apparatus
What do you need to carry out the experiment?
Method
What sequence of steps is required to carry out the
experiment? Do you need a diagram?
Results
What results do you need to present? How are they best
presented? Do you need to draw a graph, highlighting your
results?
Conclusion
What do the results mean? How do the results relate to the
aim of the experiment? Did anything go wrong?
Turn to Exercise 2.1 at the back of Part 2 to record your experiment.
Part 2: Experiments
9
2 Crowding of seedlings
Imagine you are a famous scientist. Large agricultural companies come
to you to find out how close they should plant their seeds so they will
grow well and produce high yields, ensuring a profitable enterprise.
You have been asked by Plants Incorporated to run a study on a
particular species of seed. They need to know how far apart to plant the
seeds for the best overall yields. You have agreed to take on the
challenge, allowing five weeks to carry out your tests.
You are now ready to design your experiment. Your aim is to determine
the effect of crowding on seedling growth and to establish how close
seeds can be planted for optimum seedling growth. You will be
sending your experiment and results to Plants Incorporated (which is
your teacher).
Plants Incorporated has also requested that you use a database to record
your results and a graphing package to present the data. (If you do not
have access to such programs, record the results in a table and draw a
graph by hand. You may be able to carry out activities using a database,
spreadsheet and a graphing program on a computer with your teacher.)
There are some guidelines that you need to follow.
10
•
Use aim, apparatus, method, results and conclusion in your report.
•
The seedlings must be grown from seeds you have planted.
•
The seeds should be planted in seed raising mix or fertilised soil.
•
Place the seed trays in a warm, sunny place where they won’t dry
out. Water all the seed trays with the same amount of water every
day or every second day. Ensure the seed trays don’t become
waterlogged as this encourages fungal disease.
•
All the seeds used should be of the same variety.
•
Measure some seedling parts (shown in the following diagram).
•
Always indicate the independent variable and a control in each of
your experiments.
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height in cm
number of leaves
Different parts of a seedling can be measured to monitor growth.
Refer to the experiment Bob did for this activity in the Appendix at the
back of this part to answer the following questions. This will give you
some more practice in experimental design.
1
Did Bob state what his control group was? Suggest what his control
group should have been and why.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
2
What was Bob’s independent variable?
_____________________________________________________
3
Do you think he set up enough seedling trays? Why/why not?
_____________________________________________________
_____________________________________________________
_____________________________________________________
4
State one way you could improve on the design of Bob’s experiment.
_____________________________________________________
_____________________________________________________
Check your answers.
Turn to Exercise 2.2 at the back of this part to record your plan and
experimental findings on the crowding of seedlings.
Part 2: Experiments
11
Summary
You should now have two experiments under way. These will have to be
checked and watered regularly over the next few weeks. You will
receive reminders throughout the rest of this topic to ensure the
completion of your experiments. The reminder is shown below:
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
As experiments are finalised, it is suggested that you complete your
recording of results in databases, spreadsheets and graphs. Shortly after
make your own conclusions, justifying these using the results data.
If you are unsure of how to use a database, graph results, justify
conclusions or write scientifically, refer to the Science resource book
for guidance.
12
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Appendix
Bob’s experiment
Aim
Does crowding have an effect on seedling growth?
Apparatus
Three pots with the same amount of seed raising mix.
Sweet pea seeds
Method
Tray 1
10 cm apart
1
Tray 1: Plant 3 seeds 10 cm apart.
2
Tray 2: Plant 5 seeds 5 cm apart.
3
Tray 3: Plant 10 seeds 2 cm apart.
4
Water the trays with the same amount of water each
day.
5
Place on the ledge in the kitchen window making sure
that they all get the same amount of sunlight.
6
Measure the average height of the seedlings in each tray
after three weeks.
7
Record the average number of leaves a seedling has
after three weeks.
Tray 2
5 cm apart
Tray 3
2 cm apart
Seed trays
Results
Part 2: Experiments
After 3 weeks
13
Seedling Tray
Average height
(cm)
Average
number of
leaves
Tray 1
10
8
Tray 2
8
6
Tray 3
5
4
12
Average height (cm)
10
8
Average height (cm)
6
Average number of
leaves on seedlings
4
2
0
tray 1
tray 2
tray 3
Average height (cm) and number of leaves on seedlings in different sowing
densities.
Conclusion
The seedlings planted 10 cm apart grew the tallest and had the
most number of leaves per plant. The seedlings planted 2 cm
apart grew the poorest, having the least number of leaves per
plant. The least crowded the seedlings are, the better the
growth rate.
It is recommended sweet pea seeds be planted at least 10 cm
apart for optimum growth.
14
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Suggested answers
Germinating seeds at different temperatures
1
Seeds germinate the quickest at 28–32°C.
2
No seeds germinated at 4–5°C nor at 38–42°C.
3
The container at room temperature was the control.
4
The temperature.
5
Increase reliability by repeating the experiment. A results table and
pie graphs could be added, displaying the number of germinated
seeds in each sample group each day.
Crowding of seedlings
1
No, he didn’t state his control group. The packet of seeds would
have recommended a distance to plant the seeds apart. He should
have planted seeds the recommended distance apart and used this as
his control group.
2
The distance the seeds were apart.
3
He could have set up at least two more seedling trays with seeds at
other distances apart to give better range of results.
4
Plant a tray with seeds 1 cm apart and another 0.5 cm apart is a
suggestion. However a range of answers are acceptable.
Part 2: Experiments
15
16
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Exercises - Part 2
Exercises 2.1 to 2.2
Name: _________________________________
Exercise 2.1
Record your experimental design on germinating a seed at
different temperatures. This allows your teacher to provide feedback
on the structure of the experiment and make any suggestions for
future experiments.
Record the aim, apparatus, method and results (table and graph,
including the axis).
You will not need to complete the results yet as these will be completed
on your own paper upon completion of the experiment.
Aim
_____________________________________________________
_____________________________________________________
Apparatus
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Method
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 2: Experiments
17
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
Results
18
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Results
cont.
Exercise 2.2
You should have just read an experiment Crowding of seedlings.
Remember, you are to imagine you are a famous scientist.
Plants Incorporated has come to you to find out how close they should
plant their seeds so they will grow well and produce excellent yields.
There are some rules that need to be followed when designing your
experiment – refer to Crowding of seedlings for these, page 10.
Your aim is to determine the effects of crowding on seedling growth and
to establish how close seeds can be planted for optimum seedling growth.
Design your own experiment based on the information in the crowding of
seedlings. If you need help with the design, refer to Bob’s example
experiment in the Appendix.
Part 2: Experiments
19
Aim
_________________________________________________
_________________________________________________
_________________________________________________
Apparatus
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
Method
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
20
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Space for a diagram:
Results
Part 2: Experiments
21
Conclusion
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
The control was: ____________________________________________
The independent variable was: _________________________________
22
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Senior Science
Preliminary course
Stage 6
Plants
Part 3: Germination and plant adaptations
2
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Senior Science Stage 6 Preliminary Course
Water for living
Plants
•
Attributes of plants
•
Experiments
•
Germination and plant adaptations
•
Plant requirements
•
Biodiversity and propagation
•
Seed storage and endangered species
Humans at Work
Local Environment
Contents
Introduction ............................................................................... 3
Germination............................................................................... 5
What is germination? ...........................................................................5
The right conditions..............................................................................6
Inhibiting germination ...........................................................................8
Promoting germination.......................................................................10
Pre–germination requirements ..........................................................13
Plant adaptations..................................................................... 17
Xerophytes..........................................................................................17
Mangroves ..........................................................................................22
Epiphytes ............................................................................................25
Self–reflection ......................................................................... 27
Summary................................................................................. 30
Appendix 1 .............................................................................. 31
Appendix 2 .............................................................................. 33
Suggested answers................................................................. 35
Exercises – Part 3 ................................................................... 41
Part 3: Germination and plant adaptations
1
2
Plants
Introduction
In Part 3, you will learn about techniques used to promote and inhibit
germination and about some native Australian species which have special
pre–germination requirements. You will also examine the adaptations of
xerophytes, mangroves and epiphytes.
In this part you will be given opportunities to learn to:
•
identify the impact of temperature, moisture and oxygen
concentration on germination rates
•
explain how the following techniques affect germination:
•
–
cold storage
–
vacuum packing
–
desiccation/dehydration
outline techniques used to promote germination and growth from
seed:
–
heat beds
–
lime pelleting
–
misting
•
describe pre–germination requirements of some identified Australian
flora
•
identify that plants have varying abilities to survive in different
moisture levels and discuss the adaptations of
–
xerophytes
–
mangroves
–
epiphytes.
Part 3: Germination and plant adaptations
3
In this part you will be given opportunities to:
•
gather information from a variety of resources to identify Australian
native seeds that are germinated by pre–treatments such as
– abrasion
– cutting
– heat
– smoke
– leaching
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
December 2002. The most up-to-date version can be found on the Board's
website at http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
4
Plants
Germination
Do you recall how seeds are produced? Both angiosperms and
gymnosperms produce seeds. Flowers are the reproductive structures
of flowering plants (angiosperms); cones are the reproductive organs
of gymnosperms.
You will investigate pollination and seed formation by angiosperms in
more detail in Part 6.
What is germination?
You should understand the concept of germination from your
temperature and seed germination experiment and from planting seeds at
home, however, you may not understand why seeds germinate.
Germination occurs when an embryo inside the seed breaks through the
seed coat and resumes growth. Chemical reactions take place inside the
seed, which stimulate the embryo to grow.
As you look at the diagram below, imagine the seed in moist, nutrient
rich soil that is well aerated, at 25°C.
seed
soil
A germinating seed
Part 3: Germination and plant adaptations
5
Think about moisture entering the seed through the seed coat, almost
doubling its water content. The resulting increase in size cracks the seed
coat. Oxygen enters the seed from the air pores in the soil.
Water fills the embryo cells, providing a moist environment for chemical
reactions to take place. Glucose in the seed reacts with oxygen in a
process called respiration. This allows the energy stored in glucose to
be released and used by the embryo for growth.
The embryo sprouts a root, then a shoot and continues to grow.
The energy released from respiration until the shoot breaks the surface of
the ground and develops a leaf. The leaf then photosynthesises, using the
sun’s energy for plant growth.
You may recall the equation for respiration below:
oxygen + glucose
carbon dioxide + water + energy
It is worthwhile committing this equation to memory as you will
encounter respiration throughout this module and in other modules in
this course.
The right conditions
You should have two experiments under way from Parts 1 and 2.
You will be reminded throughout Parts 3, 4, 5 and 6 to check and water
your seeds, seedlings and plants:
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
What are the right conditions for germination of seed?
Read the following recount on the following page to find out.
6
Plants
A fourteen year old boy had to do a Year 8 project. His mother had
plenty of seeds left after she made pumpkin soup. He decided he would
like to grow some pumpkins but he only had two weeks before his
project was due. He remembered that seeds don’t take very long to
germinate, so he decided to place the pumpkin seeds in different
environments to see which conditions would make them germinate the
quickest. He set up 15 dishes under different conditions, containing 10
pumpkin seeds each. His results are shown in the Appendix 1.
The boy set up fifteen samples containing ten pumpkin seeds each.
1
a) Write five variables or conditions from the table in the Appendix 1.
__________________________________________________
b) In how many seed samples did all ten seeds germinate?
_________________________________________________
c) Highlight the four seed sample columns in Appendix 1 in which
all ten seeds germinated and record their seed sample numbers
below.
_________________________________________________
d) Highlight the conditions each of the samples above were subject
to in the table below.
Sample __
Sample __
Sample __
Sample __
high moisture
high moisture
high moisture
high moisture
low moisture
low moisture
low moisture
low moisture
soil
soil
soil
soil
no soil
no soil
no soil
no soil
high oxygen levels
high oxygen levels
high oxygen levels
high oxygen levels
low oxygen levels
low oxygen levels
low oxygen levels
low oxygen levels
warm temperatures
warm temperatures
warm temperatures
warm temperatures
cool temperatures
cool temperatures
cool temperatures
cool temperatures
high light intensity
high light intensity
high light intensity
high light intensity
low light intensity
low light intensity
low light intensity
low light intensity
Part 3: Germination and plant adaptations
7
e) What conditions are common for all the samples above?
__________________________________________________
__________________________________________________
f)
What conditions are necessary for optimum seed germination
based on these results?
__________________________________________________
__________________________________________________
2
a) Write an aim for this experiment.
__________________________________________________
__________________________________________________
b) Suggest a control for this experiment.
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
Check your answers.
Inhibiting germination
By now you know that seeds need moisture, high oxygen concentrations
and specific temperatures for germination to occur. These conditions are
specific to each variety of seed.
1
With your understanding of the conditions necessary for germination,
you should have some ideas on what conditions would inhibit or prevent
seed germination. Record these ideas below.
_____________________________________________________
_____________________________________________________
2
There are many reasons why people would want seeds to germinate.
Can you think why people would want to stop seeds germinating?
Write down your ideas.
_____________________________________________________
_____________________________________________________
Check your answers.
8
Plants
A plant seed contains a live embryo and nutrients stored to supply the
embryo with energy and materials once germination starts.
When not germinating, a seed embryo is still alive and the seed is said to
be dormant.
If the seed temperature is reduced, by placing it in liquid nitrogen
(-196°C), low temperature refrigeration (-18°C) or cool storage (1–5°C),
the chemical reactions occurring in the seed proceed very slowly or stop.
Drying (desiccation) or removal of water (dehydration) withdraws the
water that is either a solvent for, or a reactant in, chemical reactions in
the embryo.
Removing the air from around seeds in an enclosure (usually plastic) is
called vacuum packaging. The low concentration of oxygen available
reduces the rate of respiration of the embryo. Sometimes gases such as
nitrogen or carbon dioxide are introduced to reduce respiration.
3
Outline each storage method and how it inhibits germination using
the headings below.
a) Desiccation/dehydration:
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
b) Cold storage:
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
c) Vacuum packaging:
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
Check your answers.
Part 3: Germination and plant adaptations
9
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
Promoting germination
Do you, or do you know of anyone who has a greenhouse? If so, what
do they grow in it? Have you read about mini greenhouses in magazines
or seen how to make them on television? Have you heard of the
greenhouse effect and global warming?
Greenhouses allow heat in, trapping some of it inside the greenhouse.
Greenhouses can also keep in moisture, making the air humid.
How do you think the trapping of heat and moisture affects seed
germination?
Seeds need specific temperatures and moisture levels for germination
to occur. Greenhouses help create the optimum conditions for seeds
to germinate.
There are several ways germination can be promoted. Read the following
information on heat beds, lime pelleting and misting then complete
Exercise 3.1 at the back of this part.
Heat beds
You already know that seeds require specific temperatures for
germination. Nurseries use heat beds to start germination of a species
out of season eg growing daisy seedlings in winter. This method
increases the soil’s temperature.
10
Plants
There are several ways of increasing the temperature of soil.
For example, soil becomes warmer when:
•
hot water runs under soil trays
•
electric cables below the soil act like a radiator
•
overhead light bulbs are used
•
manure is placed under the beds.
The diagram below shows a manure heat bed. Manure is broken down
by bacteria, which produces heat, warming the soil above. The soil is
covered by glass or perspex to retain the heat while allowing light
through to the germinating seeds.
glass or perspex
soil
manure
earth
Manure heat bed
Lime pelleting
Peas, beans, clover, alfalfa and soybeans are all examples of legumes.
All plants, whether they are legumes or not, need nitrogen.
Some legumes need bacteria in and around their roots to help them gain
nitrogen. The bacteria take nitrogen gas from the air in the soil and react
nitrogen and oxygen joining them as nitrates. The plants can then
absorb water soluble nitrates, which help plants grow and produce seeds.
Without the bacteria to fix the nitrogen for the plant, the plant would not
survive very well. Certain legume plants need certain types of bacteria.
If you live near a farm, you may already know that farmers need to make
sure they have the right bacteria for their legume crops to grow well.
Can you think of an example of a legume? If not, you may have heard of
lucerne and lupins. These are examples of legumes. Farmers buy
legume seeds that have been covered in the correct bacteria. The only
problem is that the bacteria become inactive in acid soils. Acid soils can
Part 3: Germination and plant adaptations
11
deactivate bacteria. To stop this from happening, seeds are also covered
in agricultural lime. The lime neutralises acid in the surrounding soil,
enabling the bacteria to survive and make nitrates for the plant.
So what does all this mean with regards to lime pelleting?
Lime pelleting is simply coating a seed in lime after it’s been coated or
inoculated with bacteria. The diagram following demonstrates this.
lime coating
seed
bacteria coating
Seed, bacteria and lime. The seeds of legumes are lime pelleted before sowing
Misting
Have you ever sprayed a bottle of perfume or hair spray? If you have,
you have created a mist. Mists of water can be used to keep soil moist.
Do you have a sprinkler system in your garden that sprays fine droplets
of water over the plants? If so, you have one type of misting system.
Nurseries usually have a misting system to water their plants and
seedlings. You already know that seeds need water for germination.
Misting supplies tiny droplets of water regularly to keep the soil and soil
surface moist. This helps the seed gain water for germination. A misting
system is drawn below.
water
mist of fine
water droplets
soil
seeds
Misting keeps the soil moist to promote germination
12
Plants
Have you completed Exercise 3.1 at the back of this part? If not,
complete this before moving onto the next section.
Pre–germination requirements
Have you ever had trouble germinating seeds? Australian natives in
particular can be difficult to germinate. There are some seeds that need
more than moisture, oxygen and many specific temperatures to
germinate. Many Australian species need very specific conditions in
order for their seeds to germinate.
seeds of Acacia coriacea
seeds and pods of the
Illawarra flame tree
Australian native seeds
This activity involves cutting and pasting information from Appendix 2 at
the back of this part.
1
Cut out all the information along the dotted lines in Appendix 2 (fifteen
squares of paper).
2
Read the boxes of information and match them to the appropriate
picture.
3
Match an example of a species of seed requiring those conditions for
germination.
4
Once you have matched all five pre–germination requirements, stick
them into the blank table on the following page.
5
Check your table is correct before moving on.
Part 3: Germination and plant adaptations
13
Pre–germination
requirement
Description
Example
Check your answers.
14
Plants
Use the table on the previous page to answer the following questions.
1
a) How does heat help some seeds germinate?
__________________________________________________
__________________________________________________
__________________________________________________
b) Give an example of a species that needs leaching for its seeds to
germinate.
_________________________________________________
c) How does abrasion help some seeds germinate?
_________________________________________________
_________________________________________________
_________________________________________________
d) Give an example of a species that needs its seeds to come in
contact with smoke before they will germinate.
_________________________________________________
2
Write the question for the following answers. The first one provides
an example.
Q
What pre–treatment is required for smoke bush seeds before
germination will occur?
A
They need to come in contact with smoke or smoky water
before germination will occur.
Q
_________________________________________________
_________________________________________________
_________________________________________________
A
Cutting the seed with a sharp knife can allow water to enter the
seed.
Q
_________________________________________________
_________________________________________________
A
Q
Clianthus.
_________________________________________________
_________________________________________________
A
Acacia and Cassia.
Part 3: Germination and plant adaptations
15
Turn to Exercise 3.2 at the back of this part to report on the research you
will carry out on Australian seeds requiring pre–treatments for germination.
Optional activity
If you enjoyed learning about native Australian plants and their
pre–germination requirements, you may like to attempt to germinate
some seeds using the methods discussed in the previous activity.
Not all Australian native species need pre–germination treatments.
It is a good idea to research some native Australian plants, which require
pre–treatments. This can be done by reading seed packets in stores or
searching for information on the Internet or in libraries.
The seeds may be collected from friends, the bush (with permission if
required), neighbours, or purchased from a store.
Your research should disclose the pre–treatment required for the seeds to
germinate. You should carry out the pre–treatment with a sample of
seeds, comparing the germination rate with a control sample of seeds not
pre–treated. If no pre–treatment information is available for the seeds,
different samples of seeds could be treated with different pre–treatments
to determine what pre–treatment the species of seed requires for
germination to occur.
Use your own paper to design your experiment. Remember to include an
aim, apparatus, method, results and conclusion as you may choose to
present it to your teacher. Patience may be required as germination may
take some time.
16
Plants
Plant adaptations
Do you know the name of plants that live in the canopy of other trees?
Do you know the scientific name for plants that live in conditions of low
water supply? Do you know the name of plants living in intertidal,
salt–water zones? If so, you should recognise the terms below.
If not, the following activity will help you answer the questions above.
Use the glossary to write a meaning for the following terms in your own
words.
Xerophyte: ________________________________________________
_________________________________________________________
Epiphyte: _________________________________________________
_________________________________________________________
Mangrove: ________________________________________________
_________________________________________________________
Check your answers.
Xerophytes
Listen to the audio tape/internet audio files on Plant adaptations. Use the
information to complete the appropriate sections in the tables on xerophytes.
You will need a pencil to do representative drawings and a pen to write a
summary of the adaptation. Some sections of the table have been filled in
for you.
Part 3: Germination and plant adaptations
17
Adaptations for xerophytes
Representative drawing
Plants can have wide, dense networks
of roots to capture any available water.
Baobab tree
Succulent plants store water in their
leaves for times of drought eg pigface.
18
Plants
River gums may lose an entire branch to
cut down on water loss through the
leaves on that branch.
When guard cells become turgid (full
of water), they become shaped like a
kidney bean. This leaves an opening
called a stomate. The plant loses water
and gains gases from the air through the
stomate. When there’s little water
present in the plant, the guard cells
collapse, closing the hole and
preventing more water loss.
Part 3: Germination and plant adaptations
guard
cells full
of water
hole
open
guard
cells
collapse,
closing
the hole
19
stomates sunken in leaf
leaf cross-section
Leaves can have a thick, waxy cuticle
covering the surface of the leaf to
minimise water loss from the leaf’s
surface.
leaf curls
20
Plants
Leaves of eucalypt trees hang down
vertically in the day so not as much sun
hits the leaf directly. This reduces heat
in the leaves and therefore cuts down
on water loss.
Check your answers.
Plants in your local area
You will now investigate examples of plants in your local area, which
demonstrate some of the water saving adaptations discussed in the audio
tape/internet audio file. Some examples are easier to observe then others,
such as leaves with a waxy surface. You are to observe three different
examples, recording your observations and relating them to the plant’s
adaptations for water conservation.
You may observe the plants around your house, in your community or
ask a nursery to show you examples of plants which display water saving
adaptations.
An example has been done for you;
Adaptation: Water storage in trunk.
A tree has a very wide trunk compared with the size of the tree. The base
near the roots is very wide, with a diameter of about seven metres.
The wide trunk tapers in where the branches leave the trunk. The roots
absorb water when water is plentiful and stores it in the trunk for times
of drought.
i)
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 3: Germination and plant adaptations
21
ii) ______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
iii) ______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
iv) ______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
Mangroves
Mangrove swamp © Jane West
22
Plants
Mangroves live in very different environments to xerophytes.
Mangroves live in intertidal zones at the mouths of rivers (estuaries).
They have plenty of water, but this has a high salt content. Mangroves must
remove the salt from the water before the plant can use the water.
Mangroves have three main adaptations for surviving in high salt
environments. These are discussed in the audio tape/internet audio files.
Use the audio to summarise each adaptation in the spaces provided below.
You may need to stop and rewind the tape/files to catch all the information.
Secretion of salts
Excess salt is secreted onto the leaves of this mangrove. © Jane West
Summary: ________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Part 3: Germination and plant adaptations
23
Excluding salts
Summary: _________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Storing salts
Summary: _________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Check your answers.
Optional activity
If you live on the coast, you may observe mangroves in an estuary.
An estuary is the mouth of a river, which flows into the ocean.
Mangroves are common along the sides of estuaries but are not found in
cold climates.
There may be a boardwalk through the mangroves. However, if your area
does not have mangrove walks, take shoes you won’t mind getting covered
in mud. Shoes are essential as mangrove roots (pneumatophores) stick up
through the mud and are painful to tread on. Take a mosquito repellent, as
mangroves areas provide a perfect breeding ground for mosquitoes and
mosquito–borne viruses.
You can go on a virtual mangrove excursion at www.lmpc.edu.au/science ,
go to Biology, then 8.2 A local ecosystem.
24
Plants
Epiphytes
Do you remember what an epiphyte is? There is a picture of an epiphyte
below.
Epiphyte
Listen to the section of the Plant adaptation tape/file on epiphytes and
answer the questions below.
1
a) Where does an epiphyte live?
_________________________________________________
_________________________________________________
2
Does an epiphyte get its water from the plant it lives on?
_________________________________________________
3
There are five main ways an epiphyte can obtain water. Use the
audio tape/internet audio file to help you describe each of the five
ways epiphytes can obtain water.
a)
_________________________________________________
_________________________________________________
_________________________________________________
b)
_________________________________________________
_________________________________________________
Part 3: Germination and plant adaptations
25
__________________________________________________
c)
__________________________________________________
__________________________________________________
__________________________________________________
d)
__________________________________________________
__________________________________________________
__________________________________________________
e)
__________________________________________________
__________________________________________________
__________________________________________________
Check your answers.
Turn to and complete the revision questions in Exercise 3.3 at the back of
this part.
Have you:
?
26
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
Plants
Self reflection
Enjoyment
Here, you have an opportunity to reflect on your learning.
What activities have you enjoyed the most so far in this module?
What activities help you learn the most? Tick the boxes on the left to
indicate the activities you enjoyed the most. Colour in the boxes on the
right to indicate how much information you feel you learned and can
recall from the activity. An example has been done for you as a guide.
Percent learned
Activity
0%
❑
Tissues and organs – definitions and
examples.
❑
Tissues and organs – definitions and
examples.
❑
Exercises on Autotrophic organisms and
chloroplasts.
❑
Recording macro and micronutrients on a
picture.
❑
Drawing plant symptoms with nutrient
deficiencies.
❑
Summary crossword in Part 1.
Part 3: Germination and plant adaptations
50%
100%
27
28
❑
Researching what fertilisers contain.
❑
Designing and carrying out an experiment
on seed germination.
❑
Designing and carrying out an experiment
on the crowding of seedlings.
❑
Summarising information on inhibiting
germination.
❑
Summarising and drawing diagrams on
techniques to promote germination.
❑
Cutting and pasting information on native
plant pre–germination treatments.
❑
Answering and creating questions on
seed pre–treatments.
❑
Listening to information, summarising and
drawing diagrams of xerophytes.
❑
Investigating xerophytes around your
home.
❑
Listening and summarising information on
xerophytes.
❑
Listening and writing information on
epiphyte adaptations for gaining water.
Plants
1
Did you enjoy most of the activities?
2
Have you learned a great deal so far in this module?
3
Did you learn more from the activities you enjoyed?
4
Circle which activities you enjoy the most:
cutting and pasting
summarising
listening to audio
researching
carrying out experiments
answering questions
doing crosswords
matching sentences
filling in missing words
colouring in
reconstructing sentences
drawing diagrams
gathering information from diagrams
drawing graphs
using computer technology
observing
You should now have a good idea what activities you enjoy and what
activities you learn well from. Keep these in mind as you continue
through the module. It may help you be aware of when you are likely to
absorb information or not. Knowing your preferred learning styles can
help make your study time more effective.
Part 3: Germination and plant adaptations
29
Summary
You have learnt about the conditions required for seed germination and
how germination can be inhibited. Can you recall the terms ‘cold
storage’, ‘vacuum packaging’ and ‘desiccation’? They describe ways
seeds can be stored.
Heat beds, lime pelleting and misting are techniques used to promote
germination. You should be able to remember some examples of seeds
that require heat, smoke or abrasion before they will germinate.
You listened to audio on xerophytes, mangroves and epiphytes.
Thoughts of drawings and summaries should come to mind with
xerophytes. You should recall three adaptations mangroves have to cope
with salt and the five main ways epiphytes gain water.
Stop to think if you can remember the things mentioned in the summary
above.
Answer the true and false questions in Exercise 3.4 at the back of this part.
30
Plants
Appendix 1
Seed samples (10 seeds each)
Conditions
1
high moisture
✓
✓
✓
warm temperatures
✓
✓
✓
✓
✓
✓
✓
✓
number of seeds
germinated
1
✓
8
9
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
Part 3: Germination and plant adaptations
10
1
10
12
✓
✓
13
✓
2
✓
✓
✓
✓
10
1
✓
✓
✓
✓
0
0
15
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
14
✓
✓
✓
0
11
✓
✓
0
10
✓
✓
✓
low light intensity
7
✓
✓
high light intensity
6
✓
✓
✓
5
✓
✓
low oxygen levels
cool temperatures
4
✓
✓
no soil
high oxygen levels
3
✓
low moisture
soil
2
✓
✓
✓
✓
✓
0
0
✓
✓
10
0
31
This page is blank.
32
Plants
Appendix 2
Some seeds have a very hard coat. The coat
must be broken to allow water into the seed to
start germination. Fire or being soaked in
boiling water is required to break the coating for
these seeds to germinate.
Grevillia
(abrasion)
Cutting the seed with a sharp knife can allow
water to enter the seed but care must be taken
not to destroy the seed.
Deep yellow
wood or
Rhodosphera
rhodanthema
(leaching)
Some species require the seed to come in
contact with smoke or smoky water before
germination will occur.
smoke
Clianthus
(cutting)
Part 3: Germination and plant adaptations
heat
Acacia,
Cassia
(heat)
Seeds can be scarified by rubbing between two
sheets of sand paper until the seed coating is
thin enough to allow moisture in.
cutting
Smokebush
(Cono–sper
mum)
(smoke)
Soaking the seed in water can help the seed
absorb water and therefore germinate.
abrasion
leaching
33
This page is blank.
34
Plants
Suggested answers
The right conditions
1
a) Moisture level, soil, oxygen levels, temperature and light
intensity.
b) Four.
c) Samples 3, 5, 8 and 14.
Seed samples (10 seeds each)
1
2
✓
3
4
✓
✓
✓
✓
6
✓
✓
✓
✓
✓
✓
7
✓
✓
✓
5
✓
✓
✓
8
9
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
1
✓
10
1
10
✓
Part 3: Germination and plant adaptations
0
✓
13
✓
2
✓
✓
10
1
✓
✓
✓
✓
✓
✓
✓
0
14
0
15
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
0
✓
✓
✓
✓
12
✓
✓
✓
11
✓
✓
✓
10
✓
✓
✓
✓
✓
0
0
✓
✓
10
0
35
1
d)
Sample 3
Sample 5
Sample 8
Sample 14
high moisture
high moisture
high moisture
high moisture
low moisture
low moisture
low moisture
low moisture
soil
soil
soil
soil
no soil
no soil
no soil
no soil
high oxygen levels
high oxygen levels
high oxygen levels
high oxygen levels
low oxygen levels
low oxygen levels
low oxygen levels
low oxygen levels
warm temperatures
warm temperatures
warm temperatures
warm temperatures
cool temperatures
cool temperatures
cool temperatures
cool temperatures
high light intensity
high light intensity
high light intensity
high light intensity
low light intensity
low light intensity
low light intensity
low light intensity
e) High moisture, high oxygen levels and warm temperatures.
f)
2
The conditions necessary for optimum germination are high
moisture, high oxygen levels and warm temperatures.
a) To determine what conditions seeds require for germination.
b) A control group could have been a sample containing ten
pumpkin seeds, at room temperature with no treatments.
Inhibiting germination
1
Low moisture levels, low oxygen levels and low temperatures.
2
Saving seeds for following seasons or years.
3
Desiccation/dehydration: Respiration is slowed by dehydrating
(drawing water out of) the seed. This makes the seed last longer.
Cold storage: Respiration is slowed or stopped by storing seeds in a
fridge or a freezer as it eliminates the requirement of warmth for
germination.
Vacuum packaging: Respiration is almost stopped by storing seeds
in an oxygen free environment under low pressure.
36
Plants
Pre–germination requirements of Australian species
Pre–germination
requirement
Description
Seeds can be scarified by rubbing between
two sheets of sand paper until the seed
coating is thin enough to allow moisture in.
Example
Grevillia
(abrasion)
abrasion
Cutting the seed with a sharp knife can
allow water to enter the seed but care must
be taken not to destroy the seed.
Clianthus
(cutting)
cutting
Some seeds have a very hard coat. The coat Acacia,
must be broken to allow water into the seed Cassia
to start germination. Fire or being soaked in
boiling water is required to break the coating
for these seeds to germinate.
(heat)
heat
Some species require the seed to come in
contact with smoke or smoky water before
germination will occur.
(smoke)
smoke
Soaking the seed in water can help the seed
absorb water and therefore germinate.
leaching
Part 3: Germination and plant adaptations
Smokebush
(Cono–sper
mum)
Deep
yellow
wood
(leaching)
37
1
a) The hard seed coat is broken by the heat, allowing water into the
seed. Only then can germination begin.
b) Deep Yellow Wood
c) Seeds can be rubbed between two sheets of sand paper until the
coating is thin enough to allow moisture in to start germination.
d) Smokebush
2
b) Explain how cutting the seed coating promotes germination.
c) Give an example of a species that requires the seed to be cut
before germination will occur.
d) Give two examples of seed species that need heat before the
seed will germinate.
Plant adaptations
Xerophyte
A plant adapted to growing in regions with low water supply eg
cactus and baobab tree.
Epiphyte
A plant that grows on another plant but does not use it for food or
water eg staghorn.
Mangrove
A tree that grows in muddy estuaries in salty water.
Xerophyte
Adaptations for xerophytes
Representative drawing
Plants can have wide, dense networks
of roots to capture any available water.
Baobab trees and cacti both store water
in their trunks. In times of drought they
are well prepared to survive
Baobab tree
Succulent plants store water in their
leaves for times of drought eg pigface.
leaves full of water
38
Plants
Small, thin leaves minimise water loss
by cutting down on the surface area of
the leaf. The less surface area the leaf
has, the less water can be lost to the air.
River gums may lose an entire branch to
cut down on water loss through the
leaves on that branch.
When guard cells become turgid (full of
water), they become shaped like a
kidney bean. This leaves an opening
called a stomate. The plant loses water
and gains gases from the air through the
stomate. When there’s little water
present in the plant, the guard cells
collapse, closing the hole and
preventing more water loss.
Stomates that are sunken into the
surface of the leaf have a small humid
area above them. This draws less water
out of the stomate, saving water for the
plant.
Leaves can have a thick, waxy cuticle
covering the surface of the leaf to
minimise water loss from the leaf’s
surface.
guard
cells full
of water
hole
open
guard
cells
collapse,
closing
the hole
stomates sunken in leaf
leaf cross-section
water loss
normal leaf
less water loss
leaf with cuticle
Some leaves curl in response to drying.
The curling leaf traps humid air on the
inside, next to the leaf surface. This
stops the leaf drying out, saving water
for the plant.
Leaves of eucalypt trees hang down
vertically in the day so not as much sun
hits the leaf directly. This cuts down on
heat in the leaves and therefore cuts
down on water loss.
Part 3: Germination and plant adaptations
leaf curls
leaves
hanging
down
39
Mangroves
a)
Secretion of salts
The mangrove takes the salty water in through the roots. Special
glands, usually in the leaves, secrete the excess salt, making the
water inside the plant less salty and able to be used by the cells in the
plant.
b) Excluding salts
Tiny membranes inside the cells of the roots use a process of ultra
filtration. They only let tiny water molecules into the plant, leaving
the larger salt particles outside the plant. Eighty percent of the salt
can be excluded this way.
c)
Storing salts
Some mangroves remove the salt from the water and store it in their
leaves, which they later drop, removing the salt from the plant.
Epiphyte
1
An epiphyte lives on another tree, usually in the canopy.
2
No
3
a) Aerial roots absorb moisture from the humid air.
b) Roots collect water sitting in spaces inside gaps in the bark of a
tree.
c) Leaves channel rain water down to stem tubers. The tuber fills
with water and is stored for when it’s needed.
d) Aerial roots grow upwards, forming a dense lattice which
collects falling debris. The debris becomes moist during rain
and the epiphyte is able to survive on this moisture.
e) Dense networks of roots and debris are kept moist by leaves
channelling water to them during rain. The moisture is enough
for the plant to survive on.
40
Plants
Exercises - Part 3
Exercises 3.1 to 3.4
Name: _________________________________
Exercise 3.1
You should have read the section Promoting germination. Use this
information to outline the techniques used to promote germination.
Draw a diagram of each.
Heat beds
_____________________________________________________
_____________________________________________________
_____________________________________________________
Lime pelleting
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 3: Germination and plant adaptations
41
Misting
______________________________________________________
______________________________________________________
______________________________________________________
Exercise 3.2
Use any research method you have available to you to gather examples of
native Australian species that require pre–treatments for germination.
Circle the following research methods which would suit you.
•
internet search
•
contacting nurseries
•
Library research
•
contacting seed centres
•
book store search
•
magazine research
•
contacting local native plant growers
•
other
Your aim is to provide five examples of native Australian plants species
which require specific pre–treatments (other than the plant examples
indicated in the module). The pre–treatments are listed below for you to
choose from.
The five plant examples can all belong to one pre–treatment such as
abrasion, or to each of the five different pre–treatments: leaching; smoke;
heat; cutting; abrasion. In each case, the species example is to be listed
with the required pre–treatment and the source of information.
You may have noticed when a species name is written in the text, it
appears in italics. There are two names that apply to a species.
The genus name such as Homo, and species name, such as sapiens.
The genus name always begins with a capital and the species name
always begins with a lower case letter. An example is; Homo sapiens.
Italics cannot be easily identified with hand writing, instead, the genus
and species names are underlined individually; Homo sapiens.
This is the method you should use when recording your species
examples below.
42
Plants
Native Australian
species example
Pre–treatment for
germination
Source of information
_____________________ ____________________ ____________________
____________________
_____________________ ____________________ ____________________
____________________
_____________________ ____________________ ____________________
____________________
_____________________ ____________________ ____________________
____________________
_____________________ ____________________ ____________________
____________________
Exercise 3.3
a)
What are the differences between xerophytes, mangroves and
epiphytes?
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
b) Fully describe three adaptations xerophytes have for saving water.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 3: Germination and plant adaptations
43
c)
Describe two ways mangroves cope with high salt levels.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
d) Outline two ways epiphytes gain water.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
Exercise 3.4
Circle true (T) of false (F) for the following statements.
1
2
3
4
5
6
7
8
44
Lime pelleting is the coating of inoculated legume seeds
with lime.
T
F
Some native Australian seeds need special conditions in
order to germinate.
T
F
Clianthus is a species of seed that needs leaching before
germination will occur.
T
F
Vacuum packaging involved putting placing seeds in a
refrigerator.
T
F
Desiccation and dehydration is one way seeds can be
preserved.
T
F
Spraying a fine mist of water over soil regularly helps
seeds germinate.
T
F
Acacia seeds need heat to break the seeds coat for
germination to occur.
T
F
A heat bed is a bed with an electric blanket.
T
F
Plants
9
Seeds only need heat and oxygen to germinate.
10 Seeds need to be in soil to germinate.
11 Abrasion involves scratching the surface of a seed with
sand paper until the seed coating is thin enough to allow
moisture through.
12 Mangroves thrive in cold climates.
13 A xerophyte is a plant that grows on another plant but
does not use it for food or water.
14 Some xerophytes store water in their leaves.
15 Mangroves can’t stop salts from entering their roots.
16 Some mangroves can store salts in their leaves.
17 An example of an epiphyte is a staghorn.
18 An example of a xerophyte is a baobab tree.
19 Stomates play no role in conserving water in a plant.
20 An epiphyte gains its water directly from its host plant.
Part 3: Germination and plant adaptations
T
F
T
F
T
F
T
F
T
F
T
F
T
F
T
F
T
F
T
F
T
F
T
F
45
Gill Sans Bold
Senior Science
Preliminary course
Stage 6
Plants
Part 4: Plant requirements
0
20
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b
to T S
c
O EN
g
in D M
t
a
r EN
o
p
or AM
c
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2
Senior Science Stage 6 Preliminary Course
Water for living
Plants
•
Attributes of plants
•
Experiments
•
Germination and plant adaptations
•
Plant requirements
•
Biodiversity and propagation
•
Seed storage and endangered species
Humans at Work
Local Environment
Contents
Introduction ............................................................................... 2
Plant requirements for growth ................................................... 3
Limiting factors for plant growth...........................................................6
Light intensity and plant growth................................................. 7
Watering systems...................................................................... 9
Cotton irrigation – an example.............................................................9
Watering systems in nurseries ..........................................................21
Summary................................................................................. 23
Suggested answers................................................................. 25
Exercises – Part 4 ................................................................... 29
Part 4: Plant requirements
1
Introduction
In Part 4 you will learn the different requirements for plant growth, the
effects of light intensity on seedling growth and the technology involved
in delivering water to plants in nurseries and agricultural crops.
In this part you will be given opportunities to learn to:
•
identify that different plants have different requirements for growth
•
outline effects of light intensity on seedling growth
•
describe technological developments used to supply adequate water
to seeds and plants in horticulture and agriculture.
In this part you will be given opportunities to:
•
perform an investigation to identify the use of computer–assisted
watering control systems used in horticulture/agriculture and discuss
their merits.
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
December 2002. The most up-to-date version can be found on the Board's
website at http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
2
Plants
Plant requirements for growth
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
Have you ever noticed that some plant types grow well in a particular
place in the garden and others don’t? Have you ever wondered why?
If your answer is, ‘different species of plants have different requirements
for growth’, you are correct.
For example, some plants need acid soils with good drainage,
sheltered conditions and well fertilised soil before they will fruit.
These are just some examples of different plant requirements.
You will be looking at some specific examples of the requirements of
some species of vegetables.
What keeps you healthy? Immediately you should think of healthy foods
containing a variety of vitamins and minerals, drinking clean water and
regular exercise. A lack of any of these would result in poorer health.
Plants have similar requirements.
Is there a plant in a garden that seems to be healthy and growing well?
Have you ever thought why? Is it in a sunny position? Does it receive
fertiliser regularly? Are there many plants near it? Is it in a sheltered
area? What else can you attribute to the health of the plant?
The following activity outlines some plant requirements for
optimum growth, health and reproduction. Different plants have
different requirements.
Part 4: Plant requirements
3
Read through the table below and answer the following questions.
Vegetable
plant
Plant requirements
carrots
Carrots can be grown in most climates but they grow best in cool
climates with full sun or partial shade. Carrots prefer friable,
neutral soils that have decayed organic matter. Small amounts of
water are required in the first six weeks to promote good root
growth. Too much water causes the roots to crack. Too much
fertiliser will lead to excessive leaf growth.
cucumber
Cucumbers grow best in warm climates but will grow in most areas.
Vine cucumbers can be trained up a trellis to save space. The soil
needs to be prepared with compost and animal manures and limed
if too acidic. Plants need regular watering and side dressings of
urea when the plant shows signs of vigorous growth.
lettuce
Lettuce can be grown in all climates in full sun or partial shade.
Lettuces like neutral to basic soils that are mulched and well
drained. A week before planting, spread fertiliser over the bed and
side dress with urea twice during the growing cycle. Too much
water may cause fungal disease, too little can result in a small head
and bitter leaves.
onion
All climates suit onion plants. They enjoy full sun for bulb
development but do not tolerate hot beds. Onions prefer neutral to
basic soils with large amounts of compost and dressings of
fertiliser through the growing season. Onions need regular
watering. A lack of water delays growth and results in the bulb
splitting.
cauliflower
Cauliflower grows in most climates but requires cool temperatures
for head development. Must be grown out of full sun.
Plants require a heavily manured soil with a large amount of organic
matter. The soil must be basic to neutral and kept moist.
Side dressings of fertiliser will help head development.
1
4
Use the information on the requirements for plant growth above to tick
the appropriate boxes in the table on the following page.
The first one has been done for you.
Plants
✓
prefers cool climates
✓
Cauliflower
Onion
Lettuce
Cucumber
Carrot
grown in all climates
prefers warm climates
full sun
✓
partial shade
✓
shade
acid soil
neutral soil
✓
basic soil
fertiliser
organic matter (compost)
✓
manure
urea
low water
✓
medium water
a lot of water
2
State two conditions which are common for all the vegetables in the
above table.
_____________________________________________________
_____________________________________________________
3
State a requirement only one of the vegetables listed needs.
_____________________________________________________
Part 4: Plant requirements
5
4
If you live in a cool climate with neutral soils, what vegetables are
most suited to your garden’s conditions? Why?
______________________________________________________
5
Could you grow all of the identified vegetables in the same garden,
under the same conditions and expect them all to produce good
vegetables? Explain why or why not.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
Check your answers.
Limiting factors for plant growth
There are six limiting factors for plant growth:
•
water
•
mineral nutrients
•
carbon dioxide
•
humidity
•
temperature
•
light.
Successful growers of plants do their best to keep these factors from
limiting the growth of their crops. In large scale agriculture water and
mineral nutrients are the main factors that farmers can control.
In smaller scale horticulture such as plant nurseries and orchards
shading and enclosures can be used to control humidity, temperature and
light intensity. Cold climates greenhouses can be heated by burning
fossil fuels which also increase the carbon dioxide level and the amount
of photosynthesis.
6
Plants
Light intensity and plant growth
Plant growth can be affected by the intensity of light, that is the amount
of energy available.
Have you ever tried to grow plants indoors? Did they grow well?
Some indoor plants need to be placed in the sun to keep them healthy.
Light inside a house has lower intensity than light outside the house.
You have already found out that carrots require full sun (high light
intensity) and cauliflower requires shade (low light intensity).
Relative rate of photosynthesis
The graph below shows the rate of photosynthesis in water plants at
different light intensities. The light intensity reaching plants was reduced
by using filters similar to the lenses in sunglasses.
The rate of photosynthesis was measured by measuring the rate of
production of oxygen.
0
10
20
30
40
50
60
Sunlight (%)
70
80
90
100
Effect of light intensity (expressed as % of available sunlight) on rate of
photosynthesis for water plants
Use the above graph to answer the following questions for this
investigation.
Part 4: Plant requirements
7
1
State the light intensity percentage where the rate of photosynthesis is at
its highest.
_____________________________________________________
2
What is the lowest intensity of light required for maximum
photosynthesis?
_____________________________________________________
3
Use the above graph to explain why the two plants below are different
sizes even though they were planted at the same time two years before.
50% light
intensity
100% light
intensity
______________________________________________________
______________________________________________________
______________________________________________________
Check your answers.
Light intensity and its direction may need to be controlled in a plant
nursery where seedlings are grown. Some seedlings grow best under full
sunlight. Others require different levels of shading to reduce light
intensity. Light intensity varies with seasons. A seedling that grows
well during winter in full sunlight may need extensive shading to grow
during summer.
If the seedlings being grown in a nursery are for ornamental plants then
care is needed to make sure that the seedling is uniformly surrounded by
light. A seedling that has strong light coming from one direction may
grow in the direction of the strong light, particularly if the light intensity
available is below the desired level. This can result in a deformed plant
leaning in one direction.
8
Plants
Watering systems
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
Watering systems are widely used in agriculture and horticulture to
supplement rainfall. The watering methods vary from industry to
industry. You may already know of a watering system used in
horticulture or agriculture.
Write down any watering systems you are already aware of and a brief
description about how they work (if you know). You could use examples
from watering systems around the house, overhead watering systems
involved in crop production or any others.
_________________________________________________________
_________________________________________________________
_________________________________________________________
Cotton irrigation – an example
Cotton is a crop that is produced on an extensive scale (broad acre).
It requires hot climates for rapid growth. A great deal of water is
required for the plants to grow, flower and fruit well. For this reason,
cotton farms usually have large dams for water storage. There are
several methods used to provide cotton plants with water. This section
deals with one method – flood irrigation.
In many instances, computers are involved in the delivery of water to
crops and cotton is no exception.
Part 4: Plant requirements
9
In this section, you will learn about the technologies involved in
delivering water to cotton crops with flood irrigation.
Read the following information, look at the pictures and answer the
questions underneath each section below.
What do cotton fields look like?
In most cases, cotton fields are worked into hills and furrows. The seeds
are planted into the top of the hills as shown below.
Hills and furrows. © Calib Buster
The furrows are used to channel water down rows. The photograph
following shows the furrows being flooded with water.
Where does the water come from?
Each field has a head ditch. A head ditch is a long channel at one end of
a field that holds water. Rubber pipes are used to carry the water out of
the head ditch, delivering it to flood the furrows. This process is called
setting pipe and is done manually.
10
Plants
Flooded furrows. © Calib Buster
Pipe being set. © Calib Buster
Most cotton fields are laser–levelled. The field slopes down, generally
one metre, from the head ditch to the end of the field. The water travels
down the furrows under the force of gravity.
Part 4: Plant requirements
11
1
a) If a field needed watering, what would have to be in the head ditch?
_________________________________________________
b) What is used to deliver water from the head ditch to the field?
_________________________________________________
c) What does the water flow down?
_________________________________________________
How does the water get into the head ditch?
Channels run throughout the farm. They carry water to all the head
ditches on the property. They act like main highways, channelling water
to where it’s needed. Gates between the channels and head ditches can
be opened and closed to regulate the water levels in the head ditches.
The gate below is between a channel and a head ditch. The gates must be
opened and closed manually.
Channel gate. © Calib Buster
12
Plants
2
a) Given that the channels are made from soil, what would you
expect to happen if a channel overflowed with water?
_________________________________________________
_________________________________________________
b) If you were in charge of the water channels and you had access
to every type of sensor, computer and farm software imaginable,
how would you ensure the channels wouldn’t overflow?
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
If a channel overflowed, it could erode a channel bank within minutes.
This would have a devastating effect on the crops, as the channels are
essential for the survival of the cotton plants. Cotton farms range in size
from 400 to 6000 hectares. This is roughly 6 km x 10 km or 3300 times
the size of the Sydney Cricket Ground!
Checking the channel heights physically would be a full time job due to
the sheer size of the farm. For this reason, the channels have sensors to
detect the height of the water in them. The information is transmitted via
radio waves to a main computer and checked. The flow of water into the
channels can then be adjusted manually. A channel is shown below with
a sensor which detects the height of the channel.
3
What problems could you foresee happening by relying on sensors
and a computer to provide information on water heights in channels?
_____________________________________________________
_____________________________________________________
_____________________________________________________
4
a) What do cotton farms have in the channels to ensure the water
does not overflow?
_________________________________________________
b) If water level heights are sent to a computer every ten minutes,
what would be the most useful way the heights could be
presented and why? eg. a table, graph, list, pie chart, in text
form.
_________________________________________________
_________________________________________________
Part 4: Plant requirements
13
Channel sensor. © Calib Buster
What does the central computer do?
The computer collects information on the heights of the channels over a
period of time. The information is displayed in the form of a graph.
This way, a rising or falling trend in water height can be shown.
The water operator can then predict the height of the channel for the next
few hours and anticipate when water gates need to be opened or closed.
An example of such a graph is shown on the next page.
The computer systems can also be operated via modem. Therefore,
water can be pumped or moved without the operator being on the farm.
14
Plants
Channel height graph.
5
If you were controlling the water on the farm, how would a graph of
the channel heights help you maintain the water levels in the
channels?
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
How does the water get into the channels?
Very large dams store the water needed for the season. Imagine a bath
full of water as a dam. The plug holds the water back from going down
the drain. Gates act as plugs in the dam walls. When they are opened,
water flows into the channels. The channels then carry water to the head
ditches to water the cotton fields.
6
a) What is the function of a storage dam?
_________________________________________________
b) How does water get from a dam, into a canal?
_________________________________________________
c) Where do you think the water in the dam comes from?
_________________________________________________
d) How would you think the water gets into the dams?
_________________________________________________
Part 4: Plant requirements
15
Storage dam. © Calib Buster
How does the water get into the dams?
The main water supply is often a river. Some cotton farms use bore
water, which is underground water. The water must be pumped into the
dam from the river or bore. These pumps can be switched on manually
or via computer. Given that the pumps can be to 20 km away from the
main buildings or further, it makes sense to run them via computer.
A river pump site is shown below.
River pumps. © Calib Buster
16
Plants
7
a) How can the pumps be switched on?
_________________________________________________
b) What problems could you foresee with switching on water
pumps via the computer from 20 km away?
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
How do they know when plants need water?
A neutron probe is used to measure soil moisture. A neutron probe is
lowered into an existing tube in the ground. It measures the soil moisture
to a depth of 1.2 m. The readings are downloaded into a computer and
graphed over time. The rate of water loss can be forecast and subsequent
watering can be organised for each field. A neutron probe is shown in
the following photographs.
Neutron probe. © Calib Buster
Part 4: Plant requirements
17
Neutron probe in use. © Calib Buster
8
a) Why are soil moisture levels checked?
__________________________________________________
__________________________________________________
b) What is used to check moisture levels in the soil profile?
__________________________________________________
c) If soil moisture information is loaded into a computer, how
should the results be presented usefully? Why?
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
d) If you were organising the watering of each field, how would
soil moisture information help you?
__________________________________________________
__________________________________________________
18
Plants
e) Explain any problems you could foresee with using this method
for monitoring soil moisture.
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
What if there is water left over after irrigation?
After a field has been flooded or irrigated, water is often left over.
The excess water is channelled back to a ditch and pumped back into a
canal. All the water is recycled to minimise chemical contamination of
the natural waterways.
9
Outline the functions of each of the aspects of irrigation. Use the
information on the cotton irrigation system described to help you
with your answers.
a) Furrow
_________________________________________________
_________________________________________________
b) Head ditch
_________________________________________________
_________________________________________________
c) Channel
_________________________________________________
_________________________________________________
d) Channel gate
_________________________________________________
_________________________________________________
e) Channel sensor
_________________________________________________
_________________________________________________
f)
Dam
_________________________________________________
_________________________________________________
Part 4: Plant requirements
19
g) Pumps
__________________________________________________
__________________________________________________
h) Neutron probe
__________________________________________________
__________________________________________________
i)
Computer (for channel sensors)
__________________________________________________
__________________________________________________
j)
Computer (for soil moisture)
__________________________________________________
__________________________________________________
k) Computer (for water pumps)
__________________________________________________
__________________________________________________
Check your answers.
Turn to Exercise 4.1 at the back of this part to summarise the technology
involved in the watering of cotton plants.
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
The next section looks at watering systems on a smaller scale.
20
Plants
Watering systems in nurseries
Nurseries propagate plants for sale. In this section, you are required to
investigate a computer–assisted watering system in your local nursery.
If your closest nursery relies on manual watering, or you don’t have a
nursery close by, contact a commercial nursery elsewhere.
Use one of the following methods to gather your information; in person,
by phone, by fax or email. Complete the questions that follow and
provide a summary on the watering system they use at the end.
After information is collected, it must be refined if answering specific
questions or summarising. A first draft allows the writer to organise the
information in order, allowing for mistakes. A writer may choose to do
several drafts before recording final answers or summaries.
It is suggested you draft your answers on another sheet first before
recording your final answers here.
The name of the nursery:_____________________________________
a)
Would the nursery be considered a small, medium or large scale
nursery?
_____________________________________________________
b) Does the nursery have a watering system in place?
_____________________________________________________
c)
What type of watering system is it? (eg. drip, mist, spray.)
_____________________________________________________
d) Is the watering system set to a timer? If so, how does it control the
watering?
_____________________________________________________
_____________________________________________________
_____________________________________________________
e)
If the watering system is timer–driven, when and for how long are
seedlings watered?
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 4: Plant requirements
21
f)
When and for how long are established plants watered?
______________________________________________________
______________________________________________________
g) Is the watering system computer–assisted? If so, what does it
control?
______________________________________________________
______________________________________________________
______________________________________________________
e)
Is there any additional information about the watering system you
find interesting?
______________________________________________________
______________________________________________________
______________________________________________________
Turn to Exercise 4.2 at the back of Part 4. You are asked to summarise the
watering system used by the nursery you contacted above.
22
Plants
Summary
Match the answers with the following questions by drawing a line
between them.
Why can’t all vegetables be grown
in the same garden at the same
time?
The rate of photosynthesis is at a
maximum from 80% – 100% light
intensity
What are two examples of plant
requirements?
They all have different
requirements for optimum growth
Does the rate of photosynthesis
increase with the intensity of light?
Yes
Why do plants at 90 % light
intensity grow as much as plants
at 100 % intensity?
A cool climate and full sun
What type of irrigation is
commonly used on cotton farms?
Soil moisture
What do neutron probes test for?
To move water from one place to
another
How is technology involved in
water channels on cotton farms?
Soil moisture and water heights in
channels
What things do computers graph
on cotton farms?
Flood irrigation
What is the function of water
pumps on cotton farms?
Sensors detect the water levels in
channels.
Check your answers.
Part 4: Plant requirements
23
24
Plants
Suggested answers
grown in all climates
✓
prefers cool climates
✓
✓
✓
✓
Cauliflower
Onion
Lettuce
Cucumber
Carrot
Plant requirements for growth
✓
✓
✓
prefers warm climates
full sun
✓
✓
partial shade
✓
✓
✓
✓
shade
acid soil
✓
✓
✓
basic soil
✓
✓
✓
fertiliser
✓
✓
neutral soil
organic matter (compost)
✓
✓
✓
✓
✓
manure
medium water
a lot of water
Part 4: Plant requirements
✓
✓
✓
urea
low water
✓
✓
✓
✓
✓
✓
25
2
They can all be grown in all climates and they all require neutral
soil.
3
Any one of the following. Cucumbers preferred warmer climates;
cauliflower requires shade; lettuce requires urea; and cauliflower
requires a lot of water.
4
Carrot and cauliflower. They both prefer a cool climate and neutral
soils.
5
No. Different vegetables require different conditions such as full
sun, shade, fertiliser, urea, little water, a lot of water and so on, for
optimum growth and development. For this reason, you would not
expect all the plants to produce good vegetables under the same
conditions.
Light intensity
1
80% – 100%
2
80%
3
The plant in the shade is only receiving 50 % light intensity. This
lowers its rate of photosynthesis, therefore slowing its growth. The
plant in full sun however has 100 % light intensity. Its rate of
photosynthesis is at a maximum, therefore its growth is at a
maximum.
Cotton irrigation – an example
1
a) Water.
b) Rubber tubes.
c) Furrows.
2
a) The channels would erode, breaking the banks, losing all the
water in the channel.
b) Sensors in channels could detect water heights and
automatically beam information to gates to open and shut them,
maintaining water heights.
3
The sensors may malfunction, causing the information to be
incorrect. This could lead to the channels overflowing. Similarly it
could lead to low water levels. A power blackout would prevent
readings being taken and the readings would need to be taken
manually.
4
a) Sensors which detect the height of water in the channel.
b) The water levels are best presented in a line, as it would clearly
show the water height rising or falling over time.
26
Plants
5
You would be able to see a rising or falling trend. This would help
you predict the water height in the next few hours, therefore helping
you determine when to open and close the feeder water gates.
6.
a) To store water for the entire cotton season.
b) Open a water gate.
c) Answers variable.
d) Answers variable.
7
a) Manually, via computer.
b) A pump may malfunction without the operator knowing.
A pump may jam up with river wood without the operator
knowing.
A power blackout would prevent the pumps being switched on
via a communication link.
8
a) To establish when the cotton fields need to be watered.
b) A neutron probe.
c) In graph form. A graph would display a field’s soil moisture
level over several days. Soil moisture can then be forecast over
the following days.
d) The soil moisture forecasts would help you to plan when to
water fields.
e) The neutron probe may give false readings. Extremely hot days
may draw more moisture out of the soil than expected. Cloudy
days could stabilise soil moisture. Rain may render the
waterings useless.
9
a) Furrow – for channelling water down fields to water the plants.
b) Head ditch – for holding water which is used to water a field.
c) Channel – for providing water to head ditches which are used to
water fields.
d) Channel gate – to be opened and closed, allowing water into
channels or head ditches for irrigation.
e) Channel sensor – to monitor the height of the water levels in the
channels to prevent drying out and overflow.
f)
Dam – to store water for the cotton growing season.
g) Pumps – to move water into dams for storage.
h) Neutron probe – to test for soil moisture. The information is
used to organise watering schedules for the fields.
i)
Computer (for channel sensors) – to graph the water levels in
the channels over time to prevent drying out and overflow.
Part 4: Plant requirements
27
j)
Computer (for soil moisture) – to graph soil moisture levels to
organise watering schedules for the fields.
k) Computer (for water pumps) – to turn on or off water pumps
from rivers or bores, controlling the amount of water stored in
dams.
Summary
28
Why can’t all vegetables be grown
in the same garden at the same
time?
They all have different
requirements for optimum growth
What are two examples of plant
requirements?
A cool climate and full sun
Does the rate of photosynthesis
increase with the intensity of light?
Yes
Why do plants at 90 % light
intensity grow as much as plants
at 100 % intensity?
The rate of photosynthesis is at a
maximum from 80% – 100% light
intensity
What type of irrigation is
commonly used on cotton farms?
Flood irrigation
What do neutron probes test for?
Soil moisture
How is technology involved in
water channels on cotton farms?
Sensors detect the water levels in
channels
What things do computers graph
on cotton farms?
Soil moisture and water heights in
channels
What is the function of water
pumps on cotton farms?
To move water from one place to
another.
Plants
Exercises - Part 4
Exercises 4.1 to 4.2
Name: _________________________________
Exercise 4.1
Computers can assist the watering of cotton crops in four ways.
Address three of these, explaining how the technology helps supply
adequate water to the cotton crops.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Part 4: Plant requirements
29
Exercise 4.2
Summarise the watering system used by the nursery you studied in
Part 4. Explain what type of watering system it is, if it has a timer, how
often the plants are watered, if it is computer–assisted and any other
additional information.
Nursery name: _____________________________________________
Summary:
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Have you:
?
30
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
Plants
Gill Sans Bold
Senior Science
Preliminary course
Stage 6
Plants
Part 5: Biodiversity and propagation
2
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Senior Science Stage 6 Preliminary Course
Water for living
Plants
•
Attributes of plants
•
Experiments
•
Germination and plant adaptations
•
Plant requirements
•
Biodiversity and propagation
•
Seed storage and endangered species
Humans at Work
Local Environment
Contents
Introduction ............................................................................... 2
Vegetative propagation ............................................................. 3
Vegetative propagation methods.........................................................7
Identifying data sources .......................................................... 11
Biodiversity and threatened species........................................ 12
Protecting endangered species............................................... 16
Summary................................................................................. 19
Appendix 1 .............................................................................. 21
Appendix 2 .............................................................................. 23
Suggested answers................................................................. 25
Exercises – Part 5 ................................................................... 31
Part 5: Biodiversity and propagation
1
Introduction
Seeds are produced by sexual reproduction. Part 5 discusses the different
asexual reproduction methods of propagating plants. The concept of
biodiversity is introduced on audio tape/internet audio files, outlining the
importance of conservation in Australia. Australian legislation
surrounding the NSW Biodiversity Strategy is also addressed.
In this part you will be given opportunities to learn to:
•
outline ways in which vegetative propagation and regeneration occur
in Australian native plants including
–
lignotubers
–
epicormic buds
–
runners
•
identify the purposes of applying cloning technology to plants
•
discuss genetic advantages and disadvantages of cloning
•
describe processes of tissue culture and reasons for its use
•
explain the benefits of genetic diversity for a species
•
identify reasons why Australian plants become endangered
•
outline one conservation strategy used with one rare Australian
species
•
discuss reasons for conserving Australian species of plants.
In this part you will be given opportunities to:
•
identify data sources, gather, process and present information from
secondary sources to identify Australian research involving cloning
and tissue culture of plants and the purpose of this research, using an
example such as the Wollemi Pine.
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
December 2002. The most up-to-date version can be found on the Board's
website at http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
2
Plants
Vegetative propagation
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
To propagate a plant means to produce a new plant from an existing
plant. Vegetative propagation occurs in plants when parts of the plant
other than the sexual organs are used to produce a new plant.
Some vegetative propagation occurs naturally but humans have
developed additional techniques of vegetative propagation. Cuttings and
grafting are two techniques you may have heard of, or even applied
yourself, to plants. These are vegetative techniques used on plants to
propagate them asexually. Asexually means that the propagated plant
has only one parent and is therefore genetically identical to the parent
plant. In sexual reproduction, such as by production of seeds, the
embryo plant has genetic material from a male and a female parent plant.
Have you ever seen potatoes sprout roots? The potato is attempting to
vegetatively reproduce, using the energy stored in the potato. Have you
ever seen roses growing from one central stem? The rose has been
grafted onto the stem of another plant. Have you taken cuttings from
plants or divided bulbs in your garden? If so, you have vegetatively
propagated plants.
The asexual reproduction used in vegetative propagation leads to genetic
clones – offspring which contain the same genes as the sole parent.
A major advantage of vegetative propagation is its ability to increase the
quantities available of rare plants and plants that are in heavy demand.
You will look at three natural methods of vegetative propagation that
Australian plant species use and five methods humans use on plants to
propagate them.
Part 5: Biodiversity and propagation
3
1
Cut out the eight sections of information from Appendix 1 at the back of
this part. Stick them in the correct space on the two following pages by
matching the information in the boxes with the pictures and headings.
Natural vegetative propagation:
new shoot
burnt stump
lignotuber
Lignotubers
burnt tree
new
epicormic
shoot
Natural
vegetative
propagation
(by Australian
species)
Epicormic buds
Runners
4
Plants
Vegetative propagation techniques applied by humans to plants:
Cutting
Leaf cutting
tree
Vegetative
propagation
(used on
Australian
species)
Grafting
roots
sucker
suckers and division
Tissue culture
Check your answers.
Part 5: Biodiversity and propagation
5
2
Use the information from the previous activity to complete these
sentences.
a) A
ground.
is a stem growing horizontally across the
b) A
involves
tissue samples being grown on sterile nutrient mediums.
c)
involves a scion and stock.
d) A new plant will grow at a node on a
.
e) A burnt Banksia serrata tree will sprout from dormant
_______________________ buds in its trunk.
f)
Mallee is an example of a plant that can re–sprout from an
underground
.
g) Dampiera spp , Viola hedercae and Crinum are all species that can
be
to propagate new plants that are
clones of the original plant.
h) Once a scion wedge has been placed inside a stock slit, it must be
wrapped with
tape and covered with
grafting
.
i)
involve cutting a section of stem on an angle,
removing two thirds of the leaves, dipping the end in a hormone
solution and planting.
j)
Drosera binata is an example of a plant that can be asexually
propagated through
.
k)
and
are two plants
that have been successfully propagated by tissue culture.
l)
Another name for a runner is a
.
m) Two types of plants division that can be used for propagation are
_____________________ and _______________________.
Check your answers.
6
Plants
Vegetative propagation methods
Read the comprehension passages below on how you can vegetatively
propagate plants then answer the questions which follow.
Cuttings
Propagation by cuttings is an important method of multiplying species
that are difficult to propagate by seed. It is also used for plants with
low numbers of parent stock. The propagated plants are genetically
identical to the parent plant and is said to belong to the same clone as
the parent.
Typically, secateurs are used to make a clean, angled cut, 5 – 15 cm
long, near the tip of a stem. Semi–hardened wood cuttings produce the
best results for herbs. The base cut should be taken below a node and, if
a top cut is made, it should be taken just above a node.
The leaves should then be removed from the lower two thirds of the
cutting to minimise water loss during the rooting stage. If the cutting has
large leaves, two thirds of each leaf should be cut off for the same reason.
Buds or flowers are best removed from cuttings as these will drain the
cutting of the energy needed for root growth.
The use of root promoting substances is not essential, however, a better
root system is likely to develop. The hormone–based substance may be a
powder, dilute solution or concentrated solution. The base of the
cutting is dipped in a powder or solution, then planted.
The planting medium must have good drainage and the capacity to hold
some moisture. A hole should be made in the soil, the cutting inserted
and the soil firmed down around the cutting before a final watering.
Cuttings should be kept in a humid, warm environment. Placing a clear
plastic bag over the cutting can achieve this. Roots will grow best in a
soil temperature of 27°C, however, the leaves should be kept at
22 – 23°C. The use of misting can help keep leaf temperature down.
The cutting needs access to light, but care must be taken that the cutting
does not over heat, as it will cause the cutting to desiccate.
Roots are likely to form anywhere from two to twenty weeks depending
on the species. The plant is ready for transplanting when roots are
visible around the edge of the pot when gently tapped out. The plant
must then be placed in the new container and the soil mix added to it.
This minimises root damage.
Part 5: Biodiversity and propagation
7
Leaf cuttings
A leaf should be cut at its base, dipped in a root promoting substance and
planted on a slight angle. The planting medium should be the same as
used for cuttings. Roots will usually form in six to eight weeks.
Refer to Cuttings for a care and transplanting guide.
Leaf cutting is a quick, relatively simple way of propagating plants
whose seeds do not germinate easily or whose parent stock is minimal.
Division
Sucker: A sucker is a shoot growing from an underground root.
Careful severing of a sucker’s connection to the root will separate the
sucker. The new individual plant is genetically identical to the parent
plant. Care must be taken to avoid root damage when transplanting
the sucker.
Runner: Once a runner has established a new plant at a node, the runner
can be severed. The individual plant is genetically identical to the
parent plant.
Bulb: All bulbs grow offsets. The offsets are genetically identical to the
original bulb. These can be removed from the parent bulb and dried,
ready for the following season, or replanted immediately.
Tubers: Tubers are swollen roots which store food for a plant. They
commonly sprout to form new plants which are genetically identical to
the original plant. The tuber may be severed from the parent plant to
produce an individual plant.
Potting mix is suggested as the planting medium for most divided plants.
It generally contains the nutrients the plant will require for growth.
Division is one of the easiest and quickest ways to vegetatively propagate
plants. One parent can produce several plants. In general, the time taken
for the plant to grow is much less than for a cutting to strike.
Grafting
The stock and scion should be approximately the same diameter. The
scion stem should be cleanly sliced in a wedge shape. The stock should
be about three centimetres above the ground and slit down the middle. In
both cases the instrument needs to be sterile to prevent disease.
Once the graft is wrapped in grafting tape and covered with grafting wax,
it should be placed in a humid environment similar to that of a cutting.
8
Plants
After several weeks, if the scion appears to be growing, the grafting tape
may be removed. Any growth from the stock must be removed to aid
scion growth.
Grafting is commonly used on plants with preferred qualities but with
roots that are prone to disease. Grafting a desired plant onto a stable root
base can ensure the success of the scion plant.
Tissue culture
Desirable plants that are infected with a virus can be propagated, disease
free by tissue culture. Growing shoots contain cells that are actively
dividing (growing). This meristematic tissue is commonly disease free.
Once dissected under sterile conditions, the tissue is placed onto a
nutrient medium where it grows. The tissue is then divided into many
sections and placed onto sterile shoot–producing mediums. Here, the
tissue divides into leaf tissue.
The final transfer sees the leaf tissue placed onto a sterile root–producing
medium, where root tissue forms. A great deal of care is taken to keep
the level of nutrients, water, light and heat at critical levels.
When the plants are large enough, they may be taken out of the
laboratory and planted in a sterile potting mix. All of the resultant plants
are clones of the original plant without the disease. This technique has
been used in Australia to propagate black kangaroo paw (Macropidia
fuliginosa) and other rare or endangered species.
1
Use the comprehension passages above to reconstruct the following
sentences.
a) can be that used to produce Cuttings plants are to propagate by seed
difficult.
__________________________________________________
__________________________________________________
b) warm Cuttings be kept in should a humid, environment.
_________________________________________________
_________________________________________________
c) to plants needs heating access light without Propagated over.
_________________________________________________
_________________________________________________
Part 5: Biodiversity and propagation
9
d) When are of visible cutting around the edge the pot, the is ready
for roots transplantation.
__________________________________________________
__________________________________________________
e) Leaf eight roots weeks usually form will in six to.
__________________________________________________
__________________________________________________
f)
quick Division propagate is plants easy, way to vegetatively an.
__________________________________________________
__________________________________________________
g) A in graft be environment placed a humid should.
__________________________________________________
__________________________________________________
h) culture endangered tissue Rare or species propagated may be
through.
__________________________________________________
__________________________________________________
2
Fill in the missing words using the comprehension passage.
a) Three different mediums are used to propagate plants through
.
b) A cutting may be dipped in a ____________________
substance to encourage root growth.
c) ___________________ can help reproduce plants with low
parent stock.
d) Cutting roots can develop in two to
e) A planting medium for
drainage.
f)
weeks.
cuttings must have good
Severing a sucker’s connection to the root is a form of
___________________.
g)
is used for plants with roots that are
prone to disease.
h) Plants that are
by tissue
with a virus can be propagated
.
Check your answers.
10
Plants
Identifying data sources
A data source could be:
•
•
•
•
the Internet
books from a library (school, TAFE, public, etc.)
encyclopedias (print, CD , DVD, Internet)
a person with specialised knowledge working in a plant nursery.
The data you obtain from such a source becomes information if it is
meaningful data. The work you have done so far in this module should
make a lot of the data you gather about plants meaningful. Once you
understand information you are in a good position to decide how to
effectively present that information.
An increasingly important source of information is the Internet.
Information on the Internet can be less than a year old whereas
information you read in books was usually written at least a year and
sometimes more than ten years ago. However, information can be easily
and quickly placed on the Internet by just one person.
Before information is put into print in books it is usually reviewed by
others and checked by an editor. Print information in books is often
more reliable than information from the Internet. However, it is
usually quicker to compare a wide variety of sources of information
using the Internet.
In Part 1 it was pointed out that the address of a web site will give you
some idea of how reputable a source could be – .edu indicates an
educational establishment, .gov a government department, .org a
non–profit organisation and .com a commercial, for profit, organisation.
If you do not have an address of a web site you can use a search engine
such as www.google.com. This search engine had links to over three
billion web pages in 2002. When you have not used a particular search
engine before, you can usually link to a help section on the opening
(home) page. For example, the basics of using google search are at
www.google.com/help/basics.html.
Turn to Exercise 5.1 at the back of this part to identify data sources, gather,
process and present information to identify Australian plant research.
Part 5: Biodiversity and propagation
11
Biodiversity and threatened species
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
Have you heard of the term ‘biodiversity’? If not, the word can be
broken up to ‘bio’ and ‘diversity’. Given that biology is the study of life,
what do you think ‘bio’ means? Do you know what ‘diversity’ means?
Join your two definitions to establish an idea of what biodiversity means.
Maintaining biodiversity is an important step in reducing the number of
threatened species. Threatened species can be rare – few in number – or
endangered – under threat of extinction. The Wollemi Pine discovered
in 1994 is rare but, at the moment, not endangered.
In this section, you will learn the meaning of biodiversity, why it is
important and what is being done to protect it. This section is delivered
on audio tape/internet audio file.
Listen to the Biodiversity audio tape(side A)/Internet audio file on Plant
Adaptations and answer the following questions. You may need to stop the
tape/audio file several times to record your answers.
1
What does the term biodiversity stand for?
_____________________________________________________
2
What is biodiversity in general?
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
12
Plants
3
There are three levels of biodiversity. Explain each of them below.
Genetic diversity
_____________________________________________________
_____________________________________________________
_____________________________________________________
Species diversity
_____________________________________________________
_____________________________________________________
_____________________________________________________
Ecosystem diversity
_____________________________________________________
_____________________________________________________
_____________________________________________________
4
Why is biodiversity important? List as many reasons as possible.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
5
Give three examples of the economic worth of biodiversity to
Australia.
_____________________________________________________
_____________________________________________________
_____________________________________________________
6
Give three examples of how Australia has already been affected by
not maintaining genetic diversity in ecosystems.
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 5: Biodiversity and propagation
13
7
Why is maintaining biodiversity important in Australia?
______________________________________________________
______________________________________________________
______________________________________________________
8
Does Australia’s biodiversity include Australian native plants?
______________________________________________________
9
Given all you have learned about biodiversity, why is it important to
protect rare or endangered Australian plant species?
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
10 Why do species need genetic diversity?
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
11 There are nine ways plants can become endangered. Use the tape to
fill in the blank words to describe each of the nine ways.
14
•
Loss and fragmentation of _____________________ through
clearance of native_____________________.
•
Human impacts on _____________________ and forest
resources.
•
_____________________ and soil on ___________________.
•
Degradation of the marine ____________________, including
dredging and_____________________.
•
Increasing _____________________ growth and resource use,
including expanding urban and rural _____________________
development.
•
________________________ species, diseases and genetically
________________________ organisms.
•
Collection and ______________________ trade in threatened
species.
•
Inappropriate _____________ regimes.
•
Climate __________________ and air ___________________.
Plants
12 What government body decides if species are threatened?
_____________________________________________________
13 What does the TSC Act stand for?
_____________________________________________________
14 Are threat abatement plans made for each endangered species?
_____________________________________________________
15 What are the goals of a threat abatement plan?
_____________________________________________________
_____________________________________________________
_____________________________________________________
16 What determines which endangered species receives attention?
_____________________________________________________
_____________________________________________________
_____________________________________________________
17 What government agency is responsible for developing threat
abatement plans?
_____________________________________________________
18 Give two examples of agencies responsible for implementing threat
abatement plans.
_____________________________________________________
_____________________________________________________
19 You have listed reasons why biodiversity is important. Use those
reasons to explain why it is important to change community attitudes
about conserving diversity in organisms.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Check your answers.
Part 5: Biodiversity and propagation
15
Protecting endangered species
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
You may have heard of the National Parks and Wildlife Service (NPWS)
or the Commonwealth Scientific and Industrial Research Organisation
(CSIRO). These are examples of organisations that help protect
endangered native plants.
In this section, you will discover, many other agencies that help protect
endangered plants and many legislative acts, policies and strategies that
are aimed at conserving Australia’s biodiversity.
You will also be summarising the strategies used to protect a number of
different Australian species from extinction from an international level to
a local level.
Read the Simplified Context for the NSW Biodiversity Strategy in
Appendix 3 at the back of this part to answer the following questions.
1
16
For the following acts, policies, plans and agreements, place a tick
indicating what level of legislation or government controls them.
The first one has been done for you.
Plants
Conservation of Australian
Species and Communities
threatened with extinction
National Parks and Wildlife
Conservation Act, 1975
Local Environment Plans
State Rivers and Estuary
Policy
China Australia Migratory Bird
Agreement
Heritage Act, 1977
National Water Quality
Management Strategy
International
Commonwealth
National
✓
State
Local
Check your answers.
2
Provide two examples of acts, strategies or policies for each level of
government that are likely to help protect endangered native plant
species.
Local policies and programs
_____________________________________________________
_____________________________________________________
State legislation
_____________________________________________________
_____________________________________________________
State policies
_____________________________________________________
_____________________________________________________
National Agreements, strategies and programs
_____________________________________________________
_____________________________________________________
Part 5: Biodiversity and propagation
17
Commonwealth legislation
______________________________________________________
______________________________________________________
International Agreements
______________________________________________________
______________________________________________________
Turn to Exercise 5.2 at the back of this part to do a case study with your
local council.
18
Plants
Summary
Select the alternative A, B, C or D that best answers the question.
1
Vegetative propagation is a process of:
(A) asexual reproduction
(B) sexual reproduction
(C) planting seeds
(D) producing plants genetically different to the parent plant.
2
Tissue culture is not used to:
(A) produce many plants with the same qualities
(B) produce many plants with different qualities
(C) produce disease–free plants
(D) produce many plants for cropping.
3
‘The variety of life forms, the genes they contain and the ecosystems
they form’ is a definition for:
(A) biodiversity
(B) biology
(C) ecology
(D) conservation.
4
Which of the following is a threat to biodiversity?
(A) salinity
(B) pollution
(C) introduced species
(D) all of the above
Part 5: Biodiversity and propagation
19
5
A scion is:
(A) grafted onto root stock
(B) grafted to the shoot
(C) a runner
(D) a sprout from a tuber.
6
Cutting roots form best in soils at a temperature of:
(A) 20°C
(B) 25°C
(C) 27°C
(D) 30°C.
7
Three natural methods of vegetative propagation are:
(A) tissue culture, cuttings and lignotubers
(B) cuttings, runners and leaf cuttings
(C) epicormic buds, lignotubers and runners
(D) epicormic buds, grafting and lignotubers.
8
Which of the following can be divided for propagation?
(A) bulbs
(B) suckers
(C) tubers
(D) all of the above.
9
The Wollemi Pine is an Australian plant being propagated through:
(A) tissue culture
(B) cutting
(C) grafting
(D) division.
10 At local level, which of the following helps protect Australia’s
biodiversity?
(A) World Heritage Convention Agreement
(B) State of the Environment Reports
(C) NSW Coastal Policy
(D) National Strategy for Rangeland Management.
Check your answers.
20
Plants
Appendix 1
The woody, fire–resistant
underground base of a plant stem
that stores nutrients and sprouts
after old shoots have been
destroyed (by fire) eg Mallee
A shoot or branch growing out from
a dormant bud on the trunk of a
tree, usually as the result of damage
to the tree (fire) eg Banksia serrata
A 7–8 cm semi–hardened stem cut
cleanly on an angle. Two thirds of
A horizontal stem growing above
the leaves are removed from the
the ground and spreading by the
base. The base is usually dipped in
developing new plants at the nodes
a hormone solution to promote root
eg Viola hederacae. Runners are
growth before being planted. A
also called stolons.
cutting is a genetically identical
clone of the parent plant
(eg Grevillea gaudichaudii).
A semi mature leaf is cut from a
plant at the stem, dipped in a
hormone solution, to promote root
growth, and planted on a slight
angle eg Drosera binata. The
planting medium must have good
drainage and some water–holding
capacity for cuttings to strike well.
Suckers are seedlings which grow
from a tree’s roots. Stolons are
runners. Bulbs form from other
bulbs underground. Tubers are
nutrient–storing roots which sprout
new plants. All of these asexually
reproduced plants can be severed
from the parent plant and planted on
their own to produce a cloned plant
The scion’s (top plant) stem is cut
Meristematic tissue in a growing
in wedge shape and inserted in a
shoot is dissected and placed on a
cut slit of the stock (the bottom
sterile nutrient medium. Resultant
plant). The graft is bound tightly
growth (callus) is cut into many
with grafting tape and coated with
pieces and transferred to a
grafting wax. New growth on the
shoot–producing medium, where it
stock is removed to promote scion
grows to resemble leaf tissue,
growth eg Prosthera spp (scion) to
forming plantlets. The plantlets are
W. fruitcosa (stock).
transferred to a root–producing
Part 5: Biodiversity and propagation
21
This page is blank.
22
Plants
Appendix 2
Simplified Context for the NSW Biodiversity Strategy*
Local Policies and
Programs
State of the Environment Reports (SoEs), Local Environmental Plans,
Development control Plans, Plans of Management for the Community Land,
Local Approval Policies, Annual Management Plans, Property Management
Planning, local council biodiversity policies.
State Legislation
Threatened Species Conservation Act, 1995
National Parks and Wildlife Act, 1974; Wilderness Act, 1987; Crown Lands
Act, 1901 (as amended); Catchment Management Act. 1989; Water
Administration Act, 1986; Forestry Act; 1916 Fisheries Management Act,
1994; Rural lands Protection Act, 1989; Noxious Weeds Act, 1993;
Protection of the Environment Administration Act, 1991; Local Government
Act 1993, Environmental Planning and Assessment Act, 1979; Heritage Act.
1977; Coastal Protection Act, 1979; Native Vegetation Conservation Act
1997; Marine Parks Act 1997.
State Policies
NSW Biodiversity Strategy; NSW Coastal Policy, NSW Forest Policy;
Total Catchment Management; NSW Wetland Management Policy; State
Environmental Planning Policies; NSW State Ground Water Policy; NSW
Weirs Policy; Draft Nature Tourism Strategy.
National
Agreements,
Strategies and
Programs
Inter Governmental Agreement on the Environment (IGAE); National
Strategy for the Conservation of Australia’s Biological Diversity;
National Reserve System Co–operative Program; National Forest Policy
Statement; National Greenhouse Response Strategy; Decade of Landcare;
Ocean Rescue 2000; National Weeds Strategy; National Water Quality
Management Strategy; National Strategy for Rangeland Management
(draft); MDBC Basin Sustainability program; National Strategy for the
Conservation of Australian Species and Communities Threatened with
Extinction (draft).
Commonwealth
legislation
Endangered Species Protection Act, 1992; National Parks and Wildlife
Conservation Act, 1975; Australian Heritage Commission Act, 1975;
Environment Protection (Impact of Proposals) Act 1974; World Heritage
Properties Conservation Act, 1983.
International
Agreements
UN Convention on Biological Diversity; Agenda 21; World Heritage
Convention; Convention on International Trade in Endangered Species of
Wild Fauna and Flora (CITES); Bonn Convention; Ramsar Convention,
Japan Australia Migratory Bird Agreement (CAMBA).
*indicative only, not all relevant agreements, legislation and policies are shown – key
policies and legislation are highlighted
This table is taken from NSW Biodiversity – Life’s Variety 1999. NSW National Parks
and Wildlife Service. © permission granted by NSW National Parks and Wildlife
Service.
Part 5: Biodiversity and propagation
23
24
Plants
Suggested answers
Vegetative propagation
new shoot
burnt stump
lignotuber
Lignotubers
The woody, fire-resistant
underground base of a plant stem
that stores nutrients and sprouts
after old shoots have been
destroyed (by fire) eg Mallee
burnt tree
new
epicormic
shoot
Natural
vegetative
propagation
(by Australian
species)
Epicormic buds
A shoot or branch growing out from
a dormant bud on the trunk of a
tree, usually as the result of damage
to the tree (fire) eg Banksia serrata
Runners
A horizontal stem growing above
the ground and spreading by the
developing new plants at the nodes
eg Viola hederacae. Runners are
also called stolons.
Part 5: Biodiversity and propagation
25
Cutting
Leaf cutting
A 7 – 8 cm semi-hardened stem cut
cleanly on an angle. Two thirds of
the leaves are removed from the
base. The base is usually dipped in
a hormone solution to promote root
growth before being planted. A
cutting is a genetically identical clone
of the parent plant eg Grevilea
gaudichaudii.
A semi mature leaf is cut from a plant
at the stem, dipped in a hormone
solution, to promote root growth, and
planted on a slight angle eg Drosera
binata. The planting medium must
have good drainage and some
water-holding capacity for cuttings
to strike well.
tree
Vegetative
propagation
(used on
Australian
species)
roots
sucker
Grafting
suckers and division
The scion’s (top plant) stem is cut
in wedge shape and inserted in a
cut slit of the stock (the bottom
plant). The graft is bound tightly
with grafting tape and coated with
grafting wax. New growth on the
stock is removed to promote scion
growth eg Prosthera spp (scion) to
W. fruitcosa (stock).
Suckers are seedlings which grow
from a tree’s roots. Stolons are
runners. Bulbs form from other bulbs
underground. Tubers are nutrientstoring roots which sprout new plants.
All of these asexually reproduced
plants can be severed from the
parent plant and planted on their own
to produce a cloned plant eg
Dampiera spp (sucker ), Viola
hedercae (runner) and Crinum (bulb).
Meristematic tissue in a growing
shoot is disected and placed on a
sterile nutrient medium. Resultant
growth (callus) is cut into many pieces
and transferred to a shoot-producing
medium, where it grows to resemble
leaf tissue, forming plantlets. The
plantlets are transferred to a rootproducing medium, to grow into a full
plant eg orchids and potatoes.
2
26
a) A runner is a stem growing horizontally across the ground.
Plants
b) A tissue culture involves tissue samples being grown on sterile
nutrient mediums.
c) Grafting involves a scion and stock.
d) A new plant will grow at a node on a runner.
e) A burnt Banksia serrata tree will sprout from dormant
epicormic buds in its trunk.
f)
Mallee is an example of a plant that can re–sprout from an
underground lignotuber.
g) Dampiera spp , Viola hedercae and Crinum are all species that
can be divided to propagate new plants that are clones of the
original plant.
h) Once a scion wedge has been placed inside a stock slit, it must
be wrapped with grafting tape and covered with grafting wax.
i)
Cuttings involve cutting a section of stem on an angle,
removing two thirds of the leaves, dipping the end in a hormone
solution and planting.
j)
Drosera binata is an example of a plant that can be asexually
propagated through leaf cuttings.
k) Orchids and potatoes are two plants that have been successfully
propagated by tissue culture.
l)
Another name for a runner is a stolon.
m) Two types of plants division that can be used for propagation
are suckers and bulbs.
Vegetative propagation used on plants
1
a) Cuttings can be used to produce plants that are difficult to
propagate by seed.
b) Cuttings should be kept in a humid, warm environment.
c) Propagated plants needs access to light without over heating.
d) When roots are visible around the edge of the pot, the cutting is
ready for transplantation.
e) Leaf roots will usually form in six to eight weeks.
f)
Division is an easy, quick way to vegetatively propagate plants.
g) A graft should be placed in a humid environment.
h) Rare or endangered species may be propagated through tissue
culture.
2
a) Three different mediums are used to propagate plants through
tissue cultures.
Part 5: Biodiversity and propagation
27
b) A cutting may be dipped in a root–promoting substance to
encourage root growth.
c) Cuttings can help reproduce plants with low parent stock.
d) Cutting roots can develop in two to twenty weeks.
e) A planting medium for leaf cuttings must have good drainage.
f)
Severing a sucker’s connection to the root is a form of division.
g) Grafting is used for plants with roots that are prone to disease.
h) Plants that are infected with a virus can be propagated by tissue
culture.
Biodiversity and threatened species
1
Biological diversity.
2
The variety of life forms, the different plants, animals and
micro–organisms, the genes they contain and the ecosystems they
form.
3
Genetic diversity – the variety of genetic information contained in all
individual plants, animals and micro–organisms.
Species diversity – the variety of species on Earth. The number of
species and their relative abundances for a given area.
Ecosystem diversity – variety of habitats, biotic communities and
ecological processes consisting of plant, animal, fungal and
micro–organism communities and the non–living environment.
4
Soil formation, nutrient storage and cycling, plant pollination,
pollution breakdown and absorption, food, clothing, pest control,
aesthetic reasons, medicines, scientific reasons, recreational reasons
and cultural reasons.
5
Koalas – $1.1 billion per year.
Whale watching – $50 million a year.
Dorrigo National Park – $5.4 million a year.
6
72% of NSW is affected by land degradation.
Dryland salinity costs $243 million per year.
Soil structure decline costs $243 million a year in lost agricultural
production.
28
7
Provides a preventative mechanism to safeguard life–support
systems, and reduces costs caused by ecological degradation.
8
Yes.
Plants
9
Preserving endangered plants helps maintain the biodiversity of
Australian species, therefore maintaining important habitats and
genetic material that may be of use in the future. These uses may
include medicinal use, such as the Wollemi Pine, or aesthetic
purposes like National Parks.
10 To maintain variety within the species. If conditions change, the
species have a greater chance of surviving. The greater the gene
variety, the more chance a gene may favour the changed conditions,
allowing the species to survive.
11 •
Loss and fragmentation of habitat through clearance of native
vegetation.
•
Human impacts on water and forest resources.
•
Salinity and soil on degradation.
•
Degradation of the marine environment, including dredging and
trawling.
•
Increasing population growth and resource use, including
expanding urban and rural residential development.
•
Introduced species, diseases and genetically modified
organisms.
•
Collection and illegal trade in threatened species.
•
Inappropriate fire regimes.
•
Climate change and air pollution.
12 A Scientific Committee.
13 Threatened Species Conservation Act.
14 Yes.
15 Identify and list the key processes that are likely to jeopardise the
survival of threatened species, populations and ecological
communities.
16 The level of endangerment, community influences and the level of
resources available.
17 National Parks and Wildlife Service.
18 Local Councils and government agencies.
19 The community should understand that the cleanliness of the water
they drink, the air they breathe, the food they eat, the clothes they
wear, the medicines they take and the rainforests they enjoy are all
dependant on the biodiversity of organisms. Community
appreciation of these facts would help them understand that they can
play a role in conserving the diversity of species in Australia.
Part 5: Biodiversity and propagation
29
National
30
State
International
✓
Local
1
A
5
A
9
2
B
6
C
10 B
3
A
7
C
4
D
8
D
Commonwealth
✓
Conservation of Australian
Species and Communities
threatened with extinction
National Parks and Wildlife
Conservation Act, 1975
Local Environment Plans
State Rivers and Estuary
Policy
China Australia Migratory Bird
Agreement
Heritage Act, 1977
National Water Quality
Management Strategy
Protecting endangered species
1
✓
✓
✓
✓
✓
Summary
A
Plants
Exercises - Part 5
Exercises 5.1 to 5.2
Name: _________________________________
Exercise 5.1
This exercise requires you to identify Australian research involving
cloning and tissue culture of plants and the purpose of this research,
using an example such as the Wollemi Pine.
Secondary sources for this exercise are best accessed through the Internet
using a search engine. Use key words such as ‘Wollemi Pine’, ‘cloning’
and ‘tissue culture’ in your quest. After processing information from at
least six different web sites answer the questions below:
a)
Where and when was the Wollemi Pine discovered?
_____________________________________________________
_____________________________________________________
b) Why are scientists so keen to carry out research on Wollemi Pines?
_____________________________________________________
_____________________________________________________
c)
Why is most of the research carried out away from the source?
_____________________________________________________
_____________________________________________________
d) Where and how are Australian scientists propagating Wollemi
Pines?
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 5: Biodiversity and propagation
31
e)
Identify at least one male and at least one female practising
Australian scientists carrying out research on propagation of the
Wollemi Pine by cloning or tissue culture. Provide information on
their research.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
f)
Outline the conservation strategy being used to protect the rare
Australian species, the Wollemi Pine.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
32
Plants
Exercise 5.2
Local councils are often responsible for implementing biodiversity
strategies which protect endangered plants. Many local policies and
programs are listed in Appendix 2 of this part. Contact your local council
to gather more information on a local case study that aims to protect
endangered species.
Written information from your local council may be beneficial or you could
speak to a local involved in a project. Whatever your source of information,
the following questions should be addressed. If you are unable to gather
information through your local council, contact your teacher.
It is suggested you write draft answers on a separate piece of paper
before recording your final answers below.
1
What is the name of the local policy, report or plan?
_____________________________________________________
_____________________________________________________
2
What body or agency governs the policy, report or plan?
_____________________________________________________
3
Who was/is involved in formulating the policy, report or plan?
_____________________________________________________
_____________________________________________________
_____________________________________________________
4
Who is involved in implementing the policy, report or plan?
_____________________________________________________
_____________________________________________________
_____________________________________________________
5
What are the main objectives of the policy, report or plan?
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Part 5: Biodiversity and propagation
33
6
What progress has been made so far towards achieving the goals of
the policy, report or plan?
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
7
What are any future goals?
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
34
Plants
Gill Sans Bold
Senior Science
Preliminary course
Stage 6
Plants
Part 6: Seed storage and endangered species
0
20
I
er
b
to T S
c
O EN
g
in D M
t
a
r EN
o
p
or AM
c
n
2
Senior Science Stage 6 Preliminary Course
Water for living
Plants
•
Attributes of plants
•
Experiments
•
Germination and plant adaptations
•
Plant requirements
•
Biodiversity and propagation
•
Seed storage and endangered species
Humans at Work
Local Environment
Contents
Introduction ............................................................................... 2
Protecting endangered species................................................. 3
Landcare...............................................................................................3
State Forests ........................................................................................5
Storage of genetic information .................................................. 7
Seed banks...........................................................................................7
Gamete banks ......................................................................................8
Pollen collection and storage.............................................................11
Experiment conclusions .......................................................... 16
Summary................................................................................. 17
Appendix ................................................................................. 19
Suggested answers................................................................. 23
Exercises – Part 6 ................................................................... 29
Student evaluation of module
Part 6: Seed storage and endangered species
1
Introduction
Part 6 demonstrates how two agencies conserve the biodiversity of
Australian plants with interviews on audio tape/internet audio files.
Different methods of seed–saving and seed storage are addressed in this
part, and you are guided to complete the experiments from Part 2.
In this part you will be given opportunities to learn to:
•
discuss the importance of, and strategies currently used by
geneticists to develop and maintain seed and gamete banks.
In this part you will be given opportunities to:
•
gather and process information from secondary sources to
summarise one strategy used to protect one rare Australian species
•
analyse and present information from secondary sources on the
methods used to ensure biodiversity of crops and native flora
including the development and use of seed banks.
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
December 2002. The most up-to-date version can be found on the Board's
website at http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
2
Plants
Protecting endangered species
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
Many government and private agencies are responsible for the
maintenance of Australia’s biodiversity. You investigated one of these in
Part 5.
In this section you will listen to interviews with representatives of two
different agencies to find out their roles in protecting Australia’s
endangered plants.
Landcare
Many government and non–government agencies are involved in
enforcing Australia’s biodiversity strategy by protecting native
ecosystems and species. You may have learned of some agencies
recently or you may already know of some.
Now you will listen to interviews with Karen Kennedy from Landcare
and Warrick Ponder from State Forests to gain an understanding of what
each agency does to help protect and conserve native species.
What sort information do you expect to gain from the audio tape/internet
audio file?
_________________________________________________________
_________________________________________________________
Go to the Plant Adaptations audio tape side B/internet audio file for an
interview with Karen Kennedy from Landcare Australia Limited.
Listen to the interview and answer the following questions.
Part 6: Seed storage and endangered species
3
1
What are Landcare’s main objectives?
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
2
How is Landcare funded?
______________________________________________________
______________________________________________________
______________________________________________________
3
Who is involved in the development of plans and ground work for
Landcare?
______________________________________________________
______________________________________________________
______________________________________________________
4
List ten things Landcare does in order to achieve its objectives.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
5
What are two examples of on–site work that have improved
conditions for native plants or ecosystems and where they are taking
place.
______________________________________________________
______________________________________________________
______________________________________________________
4
Plants
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
6
Where do the seeds come from for land to be revegetated with native
plants?
_____________________________________________________
_____________________________________________________
_____________________________________________________
7
How would Landcare like to change community attitudes about land
conservation and why?
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Check your answers.
State Forests
Go to the Plant Adaptations audio tape side B/internet audio file for an
interview with Warrick Ponder from State Forests.
Listen to the interview then answer the following questions.
1
What are State Forests’ main objectives?
_____________________________________________________
_____________________________________________________
_____________________________________________________
2
How is State Forests funded?
_____________________________________________________
3
Who is involved in the development of plans and ground–work for
State Forests?
_____________________________________________________
_____________________________________________________
Part 6: Seed storage and endangered species
5
4
List ten things State Forests do in order to achieve their objectives.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
5
Give two examples of on–site work that have improved conditions
for native plants or ecosystems and where they are taking place.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
6
How would State Forests like to change community attitudes about
land conservation and why?
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
Check your answers.
Turn to Exercise 6.1 at the back of this part to report on your interviews with
people to find out their understanding of endangered species conservation.
6
Plants
Storage of genetic information
Have you ever wondered how the seeds you plant are prepared and
stored? What packaging do seeds come in? Is it airtight, plastic and
waterproof? Why do you think seeds are packaged the way they are?
Do you think seeds are treated before they are packaged?
What pre–treatments do you think seeds should undergo before storage?
Why? You should have some idea of the answers after studying seed
germination and respiration. This is the focus of this section.
Have you:
?
•
recorded the temperatures for Experiment 1?
•
watered your seed trays for Experiment 2?
Seed banks
Seeds can last for long periods of time in a stated of suspended
preservation called dormancy. Because of this ability to stay alive using
hardly any oxygen and very little of the stored nutrients many seeds can
be stored away in banks called seed banks. The seeds banked can be
cropping seeds for agricultural crops or native seeds of native flora.
Seeds which can be dried to a low water content and stored at low
temperatures for many years and still germinate are called orthodox
seeds. Orthodox seeds are best suited for seed banks. Seeds which
cannot be successfully stored with low water content at low temperatures
are called recalcitrant.
There are eight main steps in seed bank storage. They are listed
alphabetically below:
Part 6: Seed storage and endangered species
7
•
collection
•
packaging
•
periodic germination tests to see if the seeds are still viable
•
re–storage
•
seed drying
•
seed preparation
•
seed regeneration
•
storage.
Place the numbers 1 to 8 in front of these steps to show the sequence in
which the steps are carried out in seed bank storage.
Check your answer.
After the seeds have been collected and unwanted surrounding material
removed, the seeds are dried to 6% or less water content.
They are placed in water proof containers and typically stored at –18°C.
After a period of time the seeds are germinated. If less than 85% of
seeds germinate then plants that grow from the germinated seeds are used
to produce fresh seeds. These fresh seeds are then banked and subjected
to periodic germination tests after shorter lengths of time until the
germination rate is above 85%.
Turn to Exercise 6.2 to investigate the important Australian native seed
bank FloraBank.
Gamete banks
Did you know that flowers are the reproductive organs of plants?
If you are already aware of how flowers produce seeds, the following
information will serve as revision.
The flower on the next page shows the structure of a flower. As you read
the information that follows, find the highlighted word in the diagram.
Place a tick next to the label. This will help you understand what functions
different flower parts have.
Flowers contain sex cells (gametes). Many flowers contain male and
female sex cells, however some flowers contain only male or female sex
cells. Pollen contains a male sex cell and is produced in the anther.
The filament holds the anther up to maximise the chances of pollen
transfer through wind or contact by insects or birds. The ovary contains
the female sex cells called ova (singular: ovum). The style is part of the
8
Plants
female reproductive system that is attached to the stigma. It allows the
genetic material from the pollen to be transferred to the ovary for
fertilisation. The stigma is sticky. This helps it ‘catch’ pollen.
Flowers are colourful and have nectar to attract insects and birds.
While feeding on the nectar, they brush against the anthers, collecting
pollen on their bodies. Pollen can be transferred from flower to flower in
this way. Wind pollinated flowers rely on the wind to transfer pollen and
are not as colourful as other flowers.
Once pollen is stuck at the top of the sigma, it grows a tube down the
style to the ovary. This process is called pollination. The male genetic
material is transferred from the pollen to the ova down this tube. One
pollen grain fertilises one ovum. The ovary then protects the fertilised
ovum until they are mature seeds. In most cases, the ovary swells to
become a fruit, containing the seeds inside.
filament
style
pistil
stigma
stamen
anther
ovary
ovule
petal
sepal
Structure of the flower.
Colour the pollen in yellow, the ovules in red, the anther in orange, the
filament in blue and the stigma in pink. This will help you understand what
flower parts are being addressed in the following section on pollen storage.
Pollen can be collected and stored. Pollen contains genetic information
as gametes. The stored gametes can be used to pollinate selected flowers
from a specific plant to increase the biodiversity of the resultant seeds.
Part 6: Seed storage and endangered species
9
Pollen is very distinctive in appearance. Forensic scientists,
archaeologists, environmental scientists and palaeontologists can use
pollen traces to learn a lot about past happenings.
Iris pollen X210
Rhododendron pollen
Rye grass pollen
Eucalyptus pollen
Illustrations: Tom Brown
10
Plants
Pollen collection and storage
Do you or do know of someone who is prone to hay fever?
What triggers their attacks? In many cases, pollen is the cause of hay
fever. You have just learned that pollen contains the male gamete.
These gametes can be collected and stored to pollinate particular flowers.
Flowers pollinated this way are likely to produce seeds with particular
genetics and particular characteristics.
Because pollen is extremely small and able to maintain viability for
many years a pollen bank is the best type of gamete bank for plants.
Flowers often have male and female sex cells. If a flower is pollinated
with pollen from the same plant (self–pollination), the seed will contain
genes that are genetically identical to the original plant. If a flower is
fertilised with pollen from different plant (cross–pollination), the
resultant seeds are genetically different to the parent plant.
Cross–pollination and self–pollination have their place in maintaining the
biodiversity of plants. Both pollination types are used on plants to ensure
the biodiversity of the offspring.
The diagrams in the Appendix illustrate steps involved in using a pollen
bank. Cut the diagrams out and insert them in the table on the following
pages. Match each diagram to the information. When you have completed
this activity you will have a better idea of the operation of a pollen bank.
Information
Diagram
1 Remove small branches containing
numerous flower buds.
Part 6: Seed storage and endangered species
11
2 Place the branches in containers of
water
3 Remove all opened flowers and
leave overnight.
4 Next morning collect all flower buds
that are at the appropriate stage of
development and seal in an
air–tight container.
Air drying
1 Place anthers on paper in an
air–tight container containing silica
gel to remove moisture.
12
Plants
2 Remove anthers full of pollen
3 Seal anthers in an airtight vial.
Freeze drying
1 Remove anthers and place in a
vial.
2 Place vial in a dryer for 12 hours.
Part 6: Seed storage and endangered species
13
3 Seal and label vial.
4 Store below 0°C.
Testing Pollen and viability
1 Place a mixture of 30% sucrose
solution containing 1.5 ppm of
boron in a vial.
2 Add pollen to the vial.
14
Plants
3 Place vial in a germination cabinet
for a length of time.
4 Remove the vial, extract a small
droplet and place on a microscope
slide.
5 View the slide under a microscope
at x160 magnification to count the
number of germinated pollen grains
and calculate a germination
percentage.
Check your answers.
Part 6: Seed storage and endangered species
15
Experiment conclusions
For several weeks now, you have been watering, checking and measuring
seeds and seedlings. It is now time to:
?
•
complete your results, graph and conclusion for
Experiment 1 on seed germination at different
temperatures
•
complete your results, graph and conclusion for
Experiment 2 on the crowding of seedlings.
It is important the experiments you started in Part 2 be concluded.
You are required to analyse and present information from first hand
investigations. This will be assessed by your teacher through the
exercises you send in. Be sure to complete and draw conclusions on both
experiments, as you may be required to outline your results and
conclusions in a test.
If you are unsure how to enter your results into a spreadsheet, graph your
results or word your conclusions, refer to the Science resource book for
this course or contact your teacher. If your experiments are not quite
finished, let your teacher know and complete them when you can.
If something went wrong, contact your teacher for guidance as to how to
complete the conclusions.
Don’t forget to send in your completed experiments.
16
•
Exercise 2.1 on seed germination at different temperatures.
•
Exercise 2.2 on crowding of seedlings.
Plants
Summary
The words in the following crossword need clues written for them.
Write the corresponding clue in the across or down column.
F R E E Z E
L
O
O
C O N S E R V E
R
T
T R E E H O L L O W
A
A
T
S
A
V
B
E N D A N G E R E D
A
G
F
F
N
E
O
K
T
R
A
C U L T
V
L
I
B I O D I
R
V E R S I
E
E
C
D
L
E
R
B
F
N
O
A
P
T Y
R
E X C L U S I O N Z O N E
V A R
S
L
C
N
T
P
L
A
W
D
S
O
I
L
A
C
L
N
C
T H R E A T A B A T E M E N T P L A N
A
I
E
I
T
T
N
E
R
E
R
R
P O L L E N
W
S
D E H Y D R A T E
A N T H E R
Y
E
K
A
T
N
L A N D R A C E
T
Part 6: Seed storage and endangered species
17
Down
18
Across
Plants
Appendix
freezer
pollen
dehisced
anther
label
label
silica gel
microscope
30% sucrose solution
(1.5 ppm boron)
Part 6: Seed storage and endangered species
19
20
Plants
eucalypt pollen grain
x 160
germination cabinet
germinating pollen grain
pollen in solution
Part 6: Seed storage and endangered species
21
22
Plants
Suggested answers
Landcare
1
Sustainable natural resource management.
2
Commonwealth government through the Natural Heritage Trust.
Landcare Australia attracts sponsors for on ground projects.
3
Predominantly volunteers.
4
Landcare groups: remove and control weeds; collect seeds for
propagation; planting seeds and shrubs to link up wildlife corridors;
stop the loss of topsoil; repair eroded river banks; fence off river
banks; map storm water drains; educate the community; construct
sediment traps; replant sand dune; apply for grant funding or
sponsorship; prepare management plans; monitor changes in the
local environment; network with other groups.
5
Cumberland Plain Woodland – working with their local council, they
have undertaken some bush regeneration and erosion control work
with the help of government funding.
A school group at Terrey Hills is working with National Parks and
Wildlife and the local council to restore the bushland in which the
rare Grevillia acalii lives.
The superb parrot is an endangered species. The south west slopes
north west of Canberra is being revegetated as breeding ground for
the parrot.
6
Where possible, seeds from the area are collected and used. If the
site is degraded, seeds are bought in from other sources.
7
Each person can make a difference. It is hard to put a price on the
environment. If more money was put into protecting our endangered
ecosystems, it would cost less in the end.
Part 6: Seed storage and endangered species
23
State Forests
1
The role of State Forests is to manage the growth and sustainable
logging of forests for timber whilst actively conserving Australian
flora and fauna.
2
State forests are almost fully self–funded.
3
Seventy ecology staff work day and night to map an area and the
species in it before harvesting.
4
State Forests: declare some areas as National Parks; set aside special
conservation areas within state forests; carry out extensive
pre–harvesting plans; maintain wildlife corridors; leave visual
protection strips; ensure no logging zones next to National Parks;
leave buffer zones either side of waterways; leave habitat trees for
endangered animals; specify exclusion zones around endangered
plants; write management and monitoring plans.
5
In the Dorrigo area, the Dorrigo Daisy Bush was extremely rare until
State Forests cleared an area. The Dorrigo Daisy Bush began to
spring up along the sides of the road. The disruption of the ground
favoured the survival of the daisy, so State Forests use active
disturbance to conserve that species.
A native quandong tree was believed to be quite rare. State Forest
surveyed an area in Whian State Forest and found several hundred
trees. Cuttings were taken from the trees and grown in nurseries for
sale to the public, ensuring the survival of the species.
6
State Forests would like the community to understand what lengths
they go to conserve endangered plants and animals. State Forests
grow and harvest timber while maximising species conservation
Seed banks
1 collection
4 packaging
6 periodic germination tests to see if the seeds are still viable
8 re–storage
3 seed drying
2 seed preparation
7 seed regeneration
5 storage.
24
Plants
Pollen collection and storage
Information
Diagram
1 Remove small branches containing
numerous flower buds.
2 Place the branches in containers of
water.
3 Remove all opened flowers and
leave overnight.
4 Collect all flower buds that are at
the appropriate stage of
development and seal in an
air–tight container.
Air drying
1 Place anthers on paper in an
air–tight container containing silica
gel.
silica gel
2 Remove dehisced anthers.
pollen
Part 6: Seed storage and endangered species
dehisced
anther
25
3 Seal pollen in an airtight vial
label
Freeze drying
1 Remove anthers and place in a
vial.
2 Place vial in a dryer for 12 hours.
3 Seal and label vial.
4 Store below 0°C.
label
freezer
Testing pollen and viability
1 Place a mixture of 30% sucrose
and 1.5 ppm of boron in a vial.
30% sucrose solution
(1.5 ppm boron)
2 Add pollen to the vial.
pollen in solution
26
Plants
3 Place vial in a germination cabinet
for a length of time.
germination cabinet
4 Remove the vial, extract a small
droplet and place on a microscope
slide.
5 View the slide under a microscope
at x160 magnification to count the
number of germinated pollen grains
and calculate germination
percentage.
microscope
eucalypt pollen grain
x 160
germinating pollen grain
Part 6: Seed storage and endangered species
27
Summary
2
1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Down
Across
1 Agency that collects and stores native
seeds (9)
1 One seed storage method (5)
2 The site of fertilisation and seed
development (5)
3 Set aside (8)
4 Agency responsible for the growth of
timber and species conservation (12)
6 An old, dead habitat tree (10)
5 Re–plant native plants in an area (10)
8 The range of all living things (12)
7 Seed store (8)
10 The existence of a species is
threatened (10)
9 A flower fertilised with pollen from the
same plant (13)
15 An area left out from logging (13)
11 To physically protect and area by
excluding animals from entering (5)
16 One type of a particular species with
useful qualities (8)
12 A flower fertilised by pollen from a
different plant (14)
18 Plan created to recover an
endangered species (19)
13 Seed with a high water content (12)
19 Contains the male sex cell (6)
14 Government body responsible for
ecosystem restoration (8)
20 Remove water from (9)
17 Where water runs through an
ecosystem (8)
21 Pollen is produced here (6)
22 A variety of a particular species (8)
28
Plants
Exercises - Part 6
Exercises 6.1 to 6.3
Name: _________________________________
Exercise 6.1
You will now survey five different adults on their views regarding plant
conservation. You will be discussing your results in terms of community
education about the importance of maintaining biodiversity.
Ask the following questions and tally the answers in the correct box.
An example is shown below.
Yes
Is it important to protect
endangered native plants?
Question
a)
No
111
Yes
No
Maybe
Don’t
care
1
1
Maybe
Don’t
know
Is it important to protect
endangered native plants?
b) Is the government currently
protecting Australia’s
endangered plants?
c)
Is more than one government
agency responsible for
protecting endangered plants?
d) Should more be done to protect
Australia’s endangered plants?
Part 6: Seed storage and endangered species
29
In light of what you have learned about biodiversity, the strategies,
policies and plans which protect endangered plants and the views of
Landcare and State Forests, answer the following questions.
1
a) Do the people interviewed have an understanding of the
importance of protecting endangered plants? Back your answer
up with statistics.
__________________________________________________
__________________________________________________
__________________________________________________
b) If the people interviewed represent the Australian community,
how would their attitudes towards conserving endangered plants
help or hinder the government’s goal of conserving the
biodiversity of Australia’s flora and fauna? Explain your
answer.
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
2
Do the people interviewed have an accurate understanding of what is
being done to protect Australia’s native plants? Back your answer up
with statistics.
______________________________________________________
______________________________________________________
______________________________________________________
3
If the people interviewed represent the Australian community, what
education do they require about the biodiversity strategy? Explain
how improving community education could help conserve
endangered plants.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
30
Plants
Exercise 6.2
Florabank is a collaboration between Greening Australia and CSIRO
Forest and Forest Products. FloraBank aims to improve the availability
and quality of native seed for revegetation and conservation purposes.
Use Internet access to find the web site for FloraBank. Explore the web
site to learn more about how this organization operates to ensure
biodiversity of Australian native flora.
a)
Summarise one strategy that could be used to protect one rare
Australian species of plant.
b) List five guidelines issued by FloraBank that support the
development and use of seedbanks:
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Part 6: Seed storage and endangered species
31
Exercise 6.3
The United Nations Food and Agricultural Organisation (FAO) is an
international body that has encouraged the establishment of gene banks
throughout the world, especially for cropping seeds.
Use Internet access to find out more about the FAO and gene banks then
answer the questions below.
a)
32
Most gene banks are seed banks. However the genetic material of
some crops are best maintained another way. Give an example of a
crop plant that has its genetic inheritance maintained by a method
other than seed banking.
Plants
b) Provide quantitative information on the number of plants banked, number of seed banks and
other methods used to maintain the world’s genetic crop inheritance.
Part 6: Seed storage and endangered species
33
Student evaluation of module
Name: _______________________
Location: ______________________
We need your input! Can you please complete this short evaluation to
provide us with information about this module. This information will
help us to improve the design of these materials for future publications.
1
Did you find the information in the module clear and easy to
understand?
_____________________________________________________
2
What did you most like learning about? Why?
_____________________________________________________
_____________________________________________________
3
Which sort of learning activity did you enjoy the most? Why?
_____________________________________________________
_____________________________________________________
4
Did you complete the module within 30 hours? (Please indicate the
approximate length of time spent on the module.)
_____________________________________________________
_____________________________________________________
5
Do you have access to the appropriate resources? eg a computer, the
internet, scientific equipment, chemicals, people that can provide
information and help with understanding science
_____________________________________________________
_____________________________________________________
Please return this information to your teacher, who will pass it along to
the materials developers at OTEN – DE.
SSCPRE 43174 Plants
Learning Materials Production
Open Training and Education Network – Distance Education
NSW Department of Education and Training