Download PLANT FORM AND FUNCTION

PLANT FORM AND FUNCTION
BEGINS
Hi there. I’m Yosemite Sam to
present Plant form and
function to you kids!
You may not realize it, but I’m
named after a very famous
National Park in California. It’s
a high altitude protected forest
so all of us can experience
nature. Now I know I have a lot
to learn about plants, but I sure
appreciate their beauty, so I
think this section can be
interesting if you have a
positive approach.
Wonderin’ why I’m shooting my
guns. Well, Plants got ROOTS and
SHOOTS, that’s why.
SHOOTS = STEM + LEAVES
PHOTOSYNTHESIS- make sugar.
Support cell metabolism energy
needs
REQUIRE- water and mineral
supply from roots
SHOOT
Sugars
Roots absorb water at the ROOT HAIRS to
provide all plant parts with water and minerals
NO PHOTOSYNTHESIS Most Roots are
under the earth with no light!
ROOT
ROOTS need the sucrose supplied by the shoots to provide
energy for cell metabolism.
Water
and
minerals
Well ain’t that somethin’. The shoots need the
water supplied by the roots. The roots need the
sucrose energy supplied by the shoots. They are
both dependent on each other.
That’s right Sam and I’m here to talk about the
roots. Look at this carrot I’m holding. It’s a tap root
used to store sucrose reserves for the plant. That’s
why they’re delicious!
ANCHOR the plant
ABSORB – minerals and water
STORE- food
There are different types of
ROOTS.
1
– fibrous roots (1)
You know, the tap
roots do not
actually absorb
much water. It’s
the root hairs that
do it. That’s why
it’s better to
transplant with
the dirt
surrounding the
soil. There are
multitudes of root
hairs in that dirt.
• mat of thin roots that spread
out-monocots
• tap roots (2)
• 1 large vertical root
• also produces many small
lateral,
or branch roots
• dicots
– root hairs (3)
• increase absorptive
surface area
3
2
Some ROOTS are modified.
PROP ROOTS
Support tall top heavy plants ex corn
STORAGE ROOTS
AERIAL ROOTS (STRANGLING)
BUTTRESS ROOTS
Support shallow roots (often in the rainforest.)
PNEUMATOPHORE (AIR ROOTS)
Oxygen levels in water are much too low for plant cells(roots
drown). Roots get the 21% oxygen supply by having part of the
root at the surface that providing the rest of the root with oxygen
by the aerenchyma cells.
Would you believe that some of the plants even
have parasitic roots. These are Haustoria and they
penetrate into the xylem and phloem vascular tissue
of a host plant allowing the parasite to grow without
the investment in growth of the tree trunk to reach
light or roots that have to reach the ground for
water.
Parasitic plant with
HAUSTORIA
Palm trees are monocots and their
roots are fibrous, but sturdy rhizomes
help to anchor them into the ground
RHIZOME = horizontal underground stems
That’s enough rabbit. It’s time to
talk about shoots.
STEM
NODE-point of leaf attachment
INTERNODE-space between attachment
BUDS-
Terminal bud
TERMINAL(apical) BUD – growth at the top increasing plant height
AXILLARY BUDS- forms branches at nodes and specific angles
Trimming hedges cuts off the terminal buds and
promotes axillary bud growth. It’s all controlled
by plant hormones. Terminal buds exhibit apical
dominance unless you remove them.
Some of the stems are modified for
special purposes. Examples are…..
BULBS
STOLONS
TUBERS
RHIZOMES
Onions are bulbs
Strawberry runners are
stolons that allow the plant to
spread.
Potato tubers are stems
that store food under
the ground
Rhizomes of ginger
and palm trees.
My
leaves
do not
have
petioles
Leaves are
parts of the
shoot too.
Roots and stems
are indeterminate
–they continue to
grow. Leaves are
determinate. Not
all angiosperms
have leaf petioles
The Leaf
petiole
FUNCTION OF LEAVES
blade
Photosynthesis producing
ENERGY and ORGANIC
molecules for structure of plant
ex cellulose
Gas Exchange for photosynthesis
Transpiration-water loss through
guard cells
The cuticle of the leaf repels
water and prevents water
loss from the leaf cells.
Transpiration
SIMPLE VERSUS COMPOUND LEAF DESIGN
Guard cells open for
carbon dioxide but
close to conserve
water when
transpiration is high
Some of the types of modified leaves
are….
TENDRILS
SPINES
SUCCULENTS
BRACTS
REPRODUCTIVE
LEAVES
Tendrils are used to hold the
plant such as those of pea plants
Cactus spines are actually leaves
Agave is a succulent
modified for storage of
water. Remember
tequila fermentation
The red coloured leaves are bracts
that surround a group of yellow
flowers.
Some leaves release adventitous plantlets
which drop off the plant and form roots
in the soil.
Here is the leaf anatomy.
Upper cuticle
Upper epidermis
Palisade layer
Spongy layer
Lower epidermis
stoma
Lower cuticle
Remember
me?
You know plants are like animals in the
organizational heirarchy. Plants have ORGANS
performing a specific function, and these are made
of TISSUES, which in turn are made of CELLS.
ORGANS
ROOTS
STEMS
LEAVES
FLOWERS
TISSUES
DERMAL
GROUND
VASCULAR
CELLS
Parenchyma
Collenchyma
Sclerenchyma
There’s different types of plant tissues. Some are even a little
bit like that vermin rabbit that keeps showing up.
PLANT TISSUES
DERMAL= Epidermis (skin of plant)
Dermal is ya
skin the
rabbit
Ground is the
eatin’ part of
the rabbit.
Vascular is
the little
heart and
blood
vessels
Epidermis is no chloroplast
single layer of tightly
packed cells protecting
plant surface
GROUND TISSUE=Bulk of plant
Includes
photosynthetic
mesophyll, storage
VASCULAR TISSUE=transport system
Xylem moves water
and minerals
Phloem moves
sucrose water
I heard
that Sam.
Now there’s PLANT CELL types as well, they’re all
called ______chyma…
PARENCHYMA- main cell type
Eatin’ a fruit,
potato,(stem) or
salad(leaf) means eatin’
mostly parenchyma
Least specialized
Photosynthetic cells, Storage cells
Fruit, stem, leaf, roots, storage cells
Form into all other plant cell types
That celery stringy stuff that
gets caught in “yer” teeth.
That’s collenchyma
COLLENCHYMA –think Celery
A peach pit is like wood inside the
fruit. It’s made of sclerenchyma
and called a SCLEREID
Can make rope out of these fibers
Thickened primary walls
Provide support + remain alive
SCLERENCHYMA-think wood
Thick woody secondary walls. LIGNINxylem support- turns to wood
Cells don’t elongate
Dead at maturity
Sure is hot in this desert. I need water. Plants got a
vascular system that transports water around. There
are two main tissues that conduct fluids in the plant.
XYLEM – transports water and minerals
In Greek xylon
mean wood.
So xylem=
wood Okay?
Tracheids and
vessel elements
(members)mature
cells are dead
PHLOEM – transports food
(sucrose) water
Sieve plate
Phloos
mean bark.
So phloem
is in bark.
Sieve tubes and
companion cells
mature cells remain
alive
Sounds like a xylemphloem to me
Sieve tube
cells lose the
nucleus,
ribosomes,
vacuoles
So let me get this straight. The phloem has
sieve tubes and companion cells both
which are alive a maturity.
The xylem is made of
tracheids and vessel
elements, both which are
dead cells at maturity.
PHLOEM
XYLEM
I’m a lookin around at all these plants and noticin’
that some of them die after one year but the others
just keep comin’ back year after year.
I’m an
Angiosperm
too
Geranium
Perennial plants, that’s what
I want. No more havin’ to
plant seeds each year like
you have to do with
annuals. Just plant them
once and they keep comin’
back year after year.
Annual plants
Die after one season
These here are flowers. What’s this
ANGIE –SPERM and how would you
classify your carrot?
I’m an
Angiosperm
Daffodil
tulip
Perennial plants
Regenerate each year
Both are flowering plants:
Angiosperms Phylum
Anthophyta My carrot is
special . It’s a biennial
and survives for two years.
Plant Anatomy Part 1
Ends