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PLANTS
CHARACTERISTICS
Multicellular
Cell
wall of cellulose
Eukaryotic: Cells have a nucleus
Non-motile: Unable to voluntarily move.
Autotrophic: An
organism that can produce its
own food (glucose) by harnessing solar
(sun) energy via the chlorophyll in the
chloroplasts.
 All
plants are autotrophic but some plants such
as the Venus fly trap and pitcher plant can obtain
nutrients from other organisms.
ROOTS
Anchor
the plant in the ground
Accumulate & store food as starch (i.e. carrot)
Transport water & minerals to the stem
Lack chloroplasts (thus the brown color)
Taproot:
A single large root that extends deep
into the soil with smaller roots branching from it
 Adapted
carrots
for storing food for the future plant growth
beets
onions
radishes
turnips
potatoes
 Fibrous
hairs
 grasses
Roots: Have many branching roots and root
 Adventitious
Roots: AKA: prop root. Grow out of
the stem & down into the soil
 corn, African
violet
Corn
Root Parts
root: Largest & 1st root to form in a plant.
Grows down.
 Secondary root: Forms from primary root. Grows
sideways.
 Root hairs: Absorb water & minerals from the soil.
 Primary
↑
root hairs = more absorbed
Label the diagram!!
STEMS
The
above ground part of plants that supports
leaves, flowers, & fruit.
 Bryophyte
(Non-vascular): Plants lacking transport
tissues such as phloem, xylem, stomata, & even
leaves.
Liverworts,
hornworts, mosses
 Tracheophyte
(Vascular): Plants containing
transport tissues such as phloem, xylem, and
stomata.
Trees,
grasses, shrubs
STEM PARTS
Epidermis
or cork: protection
Cambium: where growth takes place
Cortex: stores food
Phloem:
Transports food (glucose) from
chloroplasts to other parts of the plant.
 “Food
flows through the phloem”
Xylem:
Transports H20 & minerals from the
roots to other parts of the plant.
 “W”ater
“X”ylem Y Z
 Herbaceous
stem: Soft, green epidermis (outer
covering) with xylem & phloem in a ring or
scattered pattern.
Monocot stem
Dicot stem
 Woody
stem: Tough, brown epidermis with xylem &
phloem in a ring pattern.
Annual
Rings: Composed of xylem cells
 Black
areas represent burns or infection
 Each year is represented by 2 bands
band – form in spring; large cells due to
plentiful H20
Dark band – form in fall; small cells due to lack of H20
Light
5
10
7
12
•7 years old
Which stem has the widest rings? (A or B)
A
Year stem C had the widest ring?
1982
 Which
stem is the oldest?
D
 Which
tree grew in the wettest area?
A
 Which
C
tree went through a fire or had an infection?
 Which
 B;
has the greatest number of rings
 Which
 A;
grew in the wettest environment?
has the widest bands
 Which
 B;
shows the oldest tree trunk?
grew in the driest environment?
has the narrowest bands
 What

Rings of xylem
 How

is counted to determine the age of a tree?
old was this tree when the core sample was taken?
8 yrs. Old
 Which

band (A, B, or C) shows the worst year of growth?
B
 Which
band (A, B, or C) shows the year with the most
rainfall?

A
 How

old was this tree in 1991?
6 years old
 What

1988
 What

year did the tree receive the most rainfall?
1989
 What

year did the tree grow the least?
1988
 What

year did the tree receive the least rainfall?
year did the tree grow the most?
1989
 If
you were walking in the woods and saw many
trees of the same species, would it be right for you
to assume that those with thicker stems were
older than those with thinner stems?
 No
Bristle cone Pine Tree in California
LEAVES
The
main photosynthetic organs of a plant.
Simple leaf: composed of a single blade
There
is always a bud at the base of a petiole.
Petiole: Connect the leaf to the stem.
Veins: Conducts food & water & support the
blade.
Compound
Leaf: Leaf consisting of multiple
leaflets (small blades)
 Palmate:
5 leaflets
 Pinnate: more than 5 leaflets
Cuticle – waxy layer
Upper Epidermis
Palisade layer
Spongy
mesophyll
Air spaces
Vascular bundle
Guard cell
Lower epidermis
stomata
cuticle
Xylem:
transports H20
Phloem: transports food (glucose)
Cuticle: waxy covering that prevents H20 loss
Guard cells: Open & close stomata for H20
& gas exchange
pore for gas and H2O exchange
 Palisade layer: Where most of the photosynthesis takes
place
 Upper epidermis (land plants): layer with few stomata
 Lower epidermis (water plants): layer with few stomata
 Stoma:
The
cells in plants are mostly water.
 Water
in the plant helps to keep the cell firm.
 In a wilting plant, H20 is lost faster than it’s replaced.
Stomata
 When
control water loss.
it is arid, the stomata close slowing H20 loss.
 In humidity, the stomata open releasing extra H20.





What is the condition of the
guard cells in picture 2?
 Swollen open
Are the stomata open or closed
in picture 3?
 Closed
What do you think the weather is
like in picture 2?
 Damp and rainy
What is the weather like in
picture 3?
 Probably hot and dry
What is the function of the
stomata?
 Control water loss
Transpiration: The movement of water out of a
plant through the stomata
PLANT REPRODUCTION
“naked seed” A plant that does
NOT have flowers for reproduction.
Gymnosperm:
 May
reproduce using spores (fern) or cones (pine
trees)
 Conifers (pine trees), palms, ferns
Angiosperm: A plant
with seeds in an enclosed
ovary and produces fruit.
 Monocot:
1 cotyledon, petals in multiples of 3,
parallel veins, 1 pore in pollen, scattered phloem
& xylem, fibrous root
 Dicot: 2 cotyledons, petals in multiples of 4 or 5,
netlike veins, 3 pores in pollen, phloem and
xylem in a ring, taproot
DICOT
MONOCOT
ANGIOSPERM REPRODUCTION
 Flowers:
the reproductive structures of a plant
Pistil (female)
Stamen (male)
petals
Copy &
Label
Sepals
FLOWER PARTS
Petals:
attract the pollinators
Pistil: female part of a flower
Stamen: male part of a flower
Sepals: protect flower in bud stage
STAMEN PARTS
 Pollen
grains: Form sperm
 Anther: Contain pollen
 Filament: Holds the anther
anther
Pollen
stamen
filament
Copy & label!
PISTIL PARTS
 Stigma:
Traps pollen grains.
 Style: Transports pollen grains
 Ovary: Holds the ovule(s) which become the fruit.
 Ovules: Hold the eggs which become the seeds.
stigma
Pistil
style
ovary
ovule
Copy & label!
stigma
style
Filament + anther + pollen
Bee Vision
POLLINATION
 Pollination:
Transfer of pollen from anther to stigma
 Cross pollination: transfer of pollen from anther to
stigma on a different flower
 Self pollination: transfer of pollen from anther to
stigma on the same flower
Copy &
Label
AFTER POLLINATION
Copy &
Label
A FRUIT IS A RIPENED OVARY
Copy &
Label
Copy &
Label
Dragon fruit
 How
many ovaries are present in the bean flower?
1
 How
many ovules are present in the bean flower?
4
 What
are the little dots shown on Day 10?
 Pollen grains
 What happens to the ovary from day 10 to day 60?
 Enlarges and becomes a fruit
 What happens to the ovule from day 10 to day 60?
 Enlarges and becomes the seed
PLANT RESPONSES
Gravitropism
(Geotropism): Growth in
response to gravity, the roots grow down into
the soil and the stems grow upward
Gravitropic mutant. Fig tree, Naples, Italy
Phototropism:
Plants produce a hormone
(chemical signal) called auxin which cause
the stem to grow toward the light.
 Thigmotropism:
The plants leaves or stem coil
around an object it has made contact with in
response to touch due to auxins (or ethelyene)
Thigmonasty:
A response due to a decrease in
intracellular pressure from osmotic changes
in response to touch. Water leaves the cells
on touch and “wilts”.
Photoperiodism:
A response to the difference
in day and night length (amount of sunlight)
that affects when a plant flowers.
PLANT REQUIREMENTS
 Water
 Sunlight
 Soil
 A certain
range of temperature
 Minerals
 pH
(acidity or alkalinity)