Download Master Gardener 2015 Basic Botany

Botany for Master Gardeners
Dr. Anne Alerding,
Associate Professor of Biology
Director, VMI Herbarium
Virginia Military Institute
[email protected]
Botanical Life forms
Fungi
Lichen
(symbiosis: fungus + algae/
cyanobacterium)
Moss
(nonvascular
plant)
Fern
(seedless
vascular plant)
Algae
(photosynthetic
protist)
Flowering plants (seeds in fruits)
Conifers (naked seeds)
Gymnosperms
produce “naked”
seeds
Scale (modified leaf)
Seed not covered
by a fruit
Ovule (future seed)
Longitudinal section through a female pine cone, showing the ovules
(which develop into seeds) borne on scales.
Angiosperms produce seeds enclosed
in a “vessel” or fruit
Fruit
(swollen ovary wall)
seed
Angiosperms are also called the
“flowering plants”
• Phylum: Anthophyta
“anthus” = flower
“phyta” = plant
As a Master Gardener, you will
learn to identify MANY plants!
Every plant has a name….
but learning names can be confusing
since there are “common names”
and “Latin” names
All living organisms are classified using
the binomial (2-name) system
Have membrane-bound organelles
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Eukarya
Multicullular, photosynthetic autotrophs
Plantae
Flowering plant
Anthophyta
One cotyledon (seed leaf)
Monocotyledonae
Small flower parts; dry, oneCommelinales
seed fruits; elongated leaves
Poaeceae
Grasses (hollow stems, achene fruits)
Zea
Tall, annual grass; male and female flowers
mays
corn
Species are sometimes further
subdivided
Variety
Cultivar
Metha piperata var. variegata
Glycine max “Hutcheson”
Scientific names often have
relevant meanings…
• Pinus virginiana
– Virginia pine
• Quercus rubra
– red oak (rubra = red in Latin)
• Trifolium repens (white clover)
– Trifolium = three leaflets
– repens = creeping stems (stolons)
• Poa pratensis (kentucky bluegrass)
– pratensis = grows in meadows
Parts of a “typical” flowering plant
Developing fruit
Nodes (areas of leaf and
axillary bud attachment)
Flower
Shoot
system
Axillary bud
Internode (area between
adjacent nodes)
Petiole Blade
Stem
Leaf
Rosette of
basal leaves
Root
system
Taproot
Branch roots
Vegetative
“vegetables”
Reproductive “seeds or
fruits”
Vegetable (vegetative)
vs. Fruit (reproductive)
Vegetable any non-reproductive
part of a plant i.e. the “vegetative”
non-flowering portion
Fruit – the swollen ovary or
accessory tissue (from a flower)
Seed – develops after egg in
ovule is fertilized, embryo
Plants can be classified (broadly)
in different ways
• Stem structures
– Herbaceous versus woody
• Life cycle
– Annual, biennial, perennial
Herbaceous versus Woody
Tomato is an annual
(1 year for its life cycle to complete)
Carrot is a Biennial
(2 years to complete its life cycle)
Year 1 Growth:
taproot and shoot
Year 2 Growth: reproduction
(flowers and seeds), which
drain reserves from taproot
Perennials
(multiple years, generally do not reproduce until
reach a certain size, then every year or so after)
Parts of a Plant:
Cells, tissues, and Organs
• Cells, Tissues
• Organs
– Stems
– Roots
– Leaves
– Reproductive (flowers, fruits)
Parts of a Plant Cell,
highlighting parts that are unique and
important to plants
Cell
wall
Vacuole (stores water;
pushes water against
the cell wall to keep
plants upright)
Vacuole
Mitochondrion (respiration)
O2
Chloroplast
(photosynthesis)
CO2
O2
CO2
Fig. 3-3, p. 49
Cells are distributed into 3 tissue systems
Leaf
Dermal (enclosing)
Vascular (conducting)
Ground (filler;
multifunctional)
Dermal
Vascular
Ground
Stem
Dermal
Vascular
Ground
Root
What are the functions of
roots, stems, and leaves?
Dermal (enclosing)
Vascular (conducting)
Ground (filler;
many functions)
Leaves:
Leaf
produce sugars, cool the plant, can
be animal attractants
Dermal
Vascular
Ground
Stems:
support leaves and fruits, conduct
Stem
sugars,
water and nutrients
(translocate), storage
Dermal
Vascular
Roots:
Ground
anchor, absorb water and nutrients,
Root
conduct
water
Stems
STEMS can be herbaceous or woody
Herbaceous
Woody
growth
growth
growth
Internal tissue structures of
herbaceous vs. woody stems
pith
no pith
In young woody stems, you can still see the
internal pith cells, which are diagnostic features
used to Identify Species
All growth is initiated at meristems (zones of cell
division) contained in “buds”
leaf
leaves
Apical
meristem
of an
active bud
Coleus
Dormant
bud
Area of cell
maturation
Root hairs
Area of cell
elongation
Area of cell division
Root Apical
meristem
Root cap
Fig. 5-11, p. 105
Bud scale
Terminal
bud
One year’s
growth
Terminal bud scale scar
Axillary bud
Leaf scar
Bundle scars
Lenticels
Node
Internode
Node
In winter, woody stem
bark and bud
structures are also
diagnostic features
Black
ash
Black
oak
Virginia Tech online tree
identification keys
http://dendro.cnre.vt.ed
u/dendrology/idit.htm
“other” stems…
Rhizome
(underground stem)
potato with swollen rhizome
extensions called tubers
Iris also has rhizomes
(e.g. Iris, ginger)
Leaf scars
Corm – underground swollen stem covered with modified
papery leaves called scales (gladiolus)
Bulb –underground modified bud
(e.g. onion, lilies, tulips)
Wild onion bulbs…
Bulb
Fleshy
leaves
Stem
Adventitious
roots
Fig. 7-14c, p. 147
Stolons/runners – aboveground horizontal
stems e.g. strawberry “runners”
Roots
Root Systems
Taproot
(deep)
Fibrous
roots
(shallow)
Like stems,
roots can be woody or herbaceous
new root growth =
herbaceous; can absorb
water and nutrients
http://www.agry.purdue.edu/turf/weeds/violet/violet%20root.htm
Woody roots cannot uptake
(cells coated with a wax)
http://www.tlcfortrees.info/root_system.htm
Most absorption occurs in ROOT HAIRS, which
extend from epidermal cells of fine roots
Root hair
Soil air
Soil water
Soil particles
radish seedling
Epidermis
Fig. 6-3b, p. 114
Movement upward
Water and mineral
nutrient absorption
Epidermis
Water and
dissolved
nutrient
minerals
Root hair
Fig. 6-6, p. 119
Lateral root roots emerge
from the internal tissues
of older roots
Ruptured epidermis
Lateral root
Prop Roots – aboveground support
Corn (Zea mays)
Young mangrove tree
(Rhizophora mangle)
Pneumatophores – obtaining oxygen!
Young mangrove tree
(Rhizophora mangle)
Two most important root crops
globally are fibrous, tuberous roots
(Sweet Potato and Cassava)
Sweet Potato (Ipomoea batatas)
20% starch
Cassava (Manihot esculenta)
5% protein
30% starch
Vitamins A&D, iron, calcium
1.5% protein
Vitamin C, Manganese
Leaves
Broad Leaf
Blade (Lamina)
Veins
Narrow Leaf
Petiole
Axillary bud
Stipules
Stem
Fig. 8-1, p. 152
Broad Leaf Blade Shapes
Mid-rib
Leaf tip (apex) and base shapes
Narrow Leaf Blade Shapes
Blade
Sheath
Leaf arrangement on the stem
Alternate
Opposite
Whorled
Fig. 8-2, p. 154
Leaf forms – simple vs. compound
with leaflets
Simple
Pinnately
compound
Palmately
compound
Leaf venation patterns
Parallel
Pinnately
netted
netted = reticulate
Palmately
netted
Leaf margins
Toothed/
serrated
smooth, no bumps
deep sinuses
Some leaves have “leaf hairs/trichomes” to reflect
light (Lamb's Ear Stachys byzantina)
Soybean
trichomes
Internal leaf structures
Cuticle (waxy cutin);
secreted by
epidermis
Upper Epidermis
Lower epidermis
Stoma
Stoma
(air pore)
Guard cells
Fig. 8-3, p. 155
Close up view of a STOMA (air pore) which is open
because the two guard cells are swollen, full of water
Guard
cells
Stoma
Epidermal cells
Open and Closed stomata
open
closed
Scanning Electron Micrograph X800.
partially
open
Reproductive: flowers and fruits
Female floral parts
Male floral parts
Male floral parts
Female floral parts
Pollen grain
(each will
produce
two sperm
cells)
Stigma
Style
Carpel(s)
Gynoecium (or
pistil) = all carpels
Anther
Ovary
Filament
Ovules
(each makes
one egg cell)
Petal
Receptacle
Sepal
Peduncle
Calyx = all sepals
Corolla = all petals
Perianth = calyx + corolla
Stamen
Androecium =
all stamens
Sometimes sepals look like petals!
3 Sepals in
outer whorl
3 petals in
next whorl
Flowers are classified based on which of
the four “parts” they possess
Complete flower – has all four parts
Incomplete flower – missing 1 or more parts
Perfect flower – has at least the male and female parts
Imperfect flower – has only one functional set of sexual
parts (male or female)
-male “staminate” flower (stamens, no pistils/carpels)
-female “pistillate” flower (pistils, no stamens)
Plants with Imperfect Flowers
• Are classified as…
– Monoecious (produces pistillate and staminate
flowers on the SAME plant)
OR
– Dioecious (produces pistillate and staminate
flowers on DIFFERENT plants)
Corn is
MONOECIOUS:
Males
Females
MALE flowers
and FEMALE
flowers on the
SAME plant
MONOECIOUS “One House”
Staminate and Pistillate Corn flowers
(usually mature at different times so one plant’s
stigma is pollinated with another plant’s pollen)
Staminate flower
w/ 3 stamens
Female silks
are styles
Male Tassel
Each “kernel” you
eat is a fertilized and
ripened ovary
http://www.backyardnature.net/fl_corn.htm
Squash is also monoecious
Ovary becomes
the “squash”
http://blogs.icta.net/plover/files/2009/08/zucchini-blossom-male-femalecsu-23jul04-lah033s.jpg
Maples are DIOECIOUS (they produce female
flowers and male flowers on separate plants)
Acer rubrum (red maple) flowers
Gynoecium of female
“pistillate” flowers
Androecium of male
“staminate” flowers
Reproduction in Flowering Plants
involves…
• 1. POLLINATION
– In seed plants, the transfer of pollen grains from
the anther to the stigma
• 2. After pollination, FERTILIZATION, or fusion
of gametes (egg/sperm), occurs – forming the
zygote which develops into an embryo (baby
plant)
Anther
Pollen
grains
Pollen tube
Stigma
1Pollination
Ovary
Ovule
Pollen
grain
Two polar
nuclei
Meiosis
and mitosis
Fertilization
Zygote
Egg
3
Sperm
cells
Fig. 9-10, p. 184
FRUITS and SEEDS develop after
fertilization…
In flowering plants, FRUIT is a mature, ripened
ovary that often provides protection and
dispersal for enclosed SEEDS
Embryo
Food supply
(endosperm)
Seed coat
Germination and growth
True leaves
2 Cotyledons
(embryonic seed leaves)
Hook
Shriveled
cotyledon
Fig. 9-22, p. 194
Fruits evolved to assist in dispersing the baby plant
(seed) away from the parent
Wind
Dispersal
Self Dispersal
Animal
Dispersal
Water
Dispersal
Acorn
Milkweed
Squirting
cucumber
Cocklebur
Coconut
Let’s look an example Fruit and Seed
Development in Lily….
A lily ovary is 3 fused carpels, each
containing ovules
Ovary wall
Ovule
Lily Ovary cross section
FRUITS/SEEDS develop after
fertilization…
FRUIT – develops from OVARY
SEED - develops from OVULE
and contains an egg.
Lily Ovary cross section
Lily fruit develops from a lily ovary
Lily Fruit
Lily fruit dries at maturity and opens along 3
sutures/seams to expose the seeds inside
Immature Fruit (fleshy)
Mature Fruit (dry)
Physiology
CO2
Leaves are the
“alveoli” of plants
O2
OVERVIEW OF PHOTOSYNTHESIS,
which occurs inside chloroplasts
Light (energy that drives
photosynthesis)
6CO2+12 H2O → C6H12O6 +6O2 +6H2O
Substrates
Sugar = goal product
The substrates for
photosynthesis diffuse
into leaf cells:
1. CO2 diffuses through
stomata
Palisade
mesophyll
Vein
Air space
Spongy
mesophyll
2. H2O diffuses from xylem in
vein
Energy (light photons)
penetrates through epidermis
into mesophyll cells
Stoma
Fig. 4-4a, p. 70
Once inside the cells,
CO2 and H2O diffuse
into chloroplasts,
where
photosynthesis
occurs
Mesophyll
cells
Outer
membrane
Thylakoid
membrane
Inner
membrane
Stroma
Thylakoid
lumen
Granum
(stack of thylakoids)
Fig. 4-4bc, p. 70
Light-Dependent Reactions and Calvin Cycle Reactions occur in
DIFFERENT locations in the chloroplast
STROMA
THYLAKOIDS
HOW is water
moved through a
plant?
Is it PUSHED up
from the bottom
or is it PULLED
from the top?
BOTH OCCUR
• Pulling from leaf surfaces= “Tension Cohesion
Model”
– Most water moves this way!
• Pushing from soil into roots = “Root Pressure”
– Not as common - mostly short plants that are not
actively moving water; spring-time
Water vapor evaorates
1 (transpiration)
from the surfaces of leaf
mesophyll cells to the
drier atmosphere through
Water
stomata. This produces a
molecules
tension that pulls water
out of leaf xylem toward
mesophyll cells.
2 Cohesion of water molecules,
caused by hydrogen bonding,
allows unbroken columns of water
to be pulled up narrow vessels
and tracheids/vessels of stem xylem.
Stoma
Tension
Cohesion
Model
3 This, in turn, pulls water up root
Root
hair
xylem, forming a continuous
column of water from root xylem to
stem xylem to leaf xylem. Movement
of water upward in root
produces a pull that causes soil
water to diffuse into the root.
Fig. 10-13, p. 214
Root Pressure
Causes Guttation
(water droplets are expelled
via hydathode openings along
margins of leaves)
Fig. 8-13, p. 166
Plants release 99% of the water they take in through
evaporation (transpiration) via stomata in leaves and
stems. Only 1% is lost through the epidermis because
epidermal cells secrete a cuticle made of a waxy
(waterproof) substance called cutin.
Palisade
mesophyll
Cuticle
Vein
(vascular
bundle)
Spongy
mesophyll
Upper
epidermis
Bundle
sheath
Xylem
Phloem
Stoma
(plural =
stomata)
Fig. 8-3, p. 155
Air space in
spongy
mesophyll
Stoma
Guard cells
Lower
epidermis
Downside of transpiration?
• Too much water loss results in plant cells losing turgor and
WILTING.
• If enough water in soil, plants can recover by taking in water
at night
Fig. 8-12, p. 166
My research on invasive plants:
Garlic Mustard (Alliaria petiolata)
Year 1: Juvenile
(vegetative rosette)
http://www.oardc.ohio-state.edu/weedguide/singlerecord.asp?id=330#
Year 2: Adult
(reproductive)
Mid 1800s
Long
Island
http://plants.usda.gov
Northeastern forest invasion by garlic
mustard decreases plant diversity
Plant
Diversit
y
# of Garlic mustard per 16m2
plot
Stinson et al., 2007 Northeastern Naturalist
14:73–88.
Garlic mustard harms mutualistic fungi of
native plants
ectomycorrhizae
http://www.ctacf.org/index.cfm/2007/3/1/Mycorrhizae-and-the-American-Chestnut-An-Underground-Tale-of-Mystery
endomycorrhizae
Research Question:
Do detritivores respond to Garlic
Mustard invasion?
Litter detritivores: Microarthropods
Soil Mites: Order
Oribatida
Springtails: Order Collembola
http://www.fcps.edu/islandcreekes/ecology/soil_mite.ht
m
http://en.wikipedia.org/wiki/File:Orchesella_cincta.jpg
Total Springtails are more abundant
in invaded sites
Springtail Density (#.m-2)
1400
P = 0.003 (invasion)
P = 0.174 (date)
1200
1000
800
Invaded
600
Uninvaded
400
200
0
28-Jun
5-Jul
Sampling Date
13-Jul