Download The study of the parts of the plant is called Plant Anatomy. Last week

The study of the parts of the plant is called Plant Anatomy. Last
week we looked at characteristics of living things, the diversity of
plants, photosynthesis, germination and some of the economic uses
for plants. This week we will be exploring different parts of plants
and their functions.
Table 1: Roots: Roots are usually underground parts of plants.
In order to be considered a TR UE root, a plant must have TR UE
vascular tissue. That is, they must have some special cells to move
water around in the plant called xylem and phloem. Plants like
moss and Elodea (the water plant we looked at) do NOT have these
special tissues. Therefore they DO NOT have TRUE roots.
True roots have a couple of purposes:
• They absorb nutrients and water
• They anchor the plant into the ground.
Let's take a look at how root can do such a good job of absorbing
water out of the soil. One structure that helps plant roots to absorb
water is the presence of root hairs. Root hairs are little hairs on
the roots that make the surface area of the root bigger. When the
surface area increases, then the amount of water that can be
absorbed increases. In other words, when the amount of surface of
the root increases, more of the root can be in contact with the
water.
TRY THIS: (IT IS VERY IMPORTANT TO LEAVE THE
PAPER TOWEL IN THE WATER ONLY A QUICK SECOND.
TOO LONG AND YOU WILL NOT SEE THE EFFECT)
1. Cut 2 pieces of paper towel that are the same size. See
the example on the table.
2. Cut "slits" in one end of one of the paper towels. Do not
cut slits on the other paper towel.
3. Roll the paper towels into tight cylinders and tape them
closed.
K. McDaniel
2004
1'")
4.
S.
At the same time, dip the end of the 2 cylinders into the
beaker of water for 3 seconds and then quickly pull them
out.
Unroll the cylinders
Which paper towel absorbed more water? Why?
Different plants can have kinds of roots systems.
• Taproots: These root systems have 1 main root and
other smaller branching roots.
• Fibrous roots: These systems are usually not as deep as
tap root systems. Usually all of the roots are the same
size and look like a group of fibers.
• Adventitious roots: These are roots that grow from
stems or branches and are usually above ground. Some
of these are used to support plants or to help plants
cling to the surface of objects.
• Stolons: Roots that grow horizontally above ground.
Sometimes new baby plants grow from these
• Bulbs: These are NOT roots at all! This is actually a
large round stem that is specialized for food storage.
Look close though and you might find some
adventitious roots on the bottom of the bulb!
• Tuber: These aren't roots either! These are also special
underground stems that store lots of starch!
• Corms: Okay! Another underground structure that is
NOT a root! This is a another special underground
fleshy stem for storage! (Crocus produce corms)
• Rhizomes: These are also underground stems that
leaves can grow up and off of. Your mom may plant
Iris rhizomes.
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2004
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Look at the root systems on the table. Fill in the chart for each
root.
(KINDERGARTEN AND YOUNGER KIDS MAY JUST WANT
TO SEE THAT DIFFERENT UNDERGROUND STRUCTURES
ARE DIFFERENT)
Table 3: Stems 'are important aboveground parts of a plant.
They have a couple of functions:
• Maximize the exposure of the plant to the sun
• Move water, nutrients and sugars around in the plant
TRY THIS: See if solutions really do move through stems.
1. Remove a stalk of celery from the solution of colored
water.
2. Measure 5 places on the stalk of celery from the bottom of
the celery stalk. (One close to the bottom, one further
from the bottom etc.) Mark these in pencil or pen on the
stalk.
3. Cut a section (a fourth inch hunk) through the mark
nearest the end of the celery in the water.
4. Look at this section under the microscope.
What do you see?
The small circles that are the same color as the solution
are the strand of vascular tissue. This is that special
xylem and phloem that moves things around in a plant
(kind of like our blood vessels).
5. N ow make another cut up the celery stalk and look at it.
Do you still see the color in the stem?
6. Repeat until you no longer see color in the celery stalk.
How far up the celery did the solution move?
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2004
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Sometimes stems can have what is called secondary growth. This
is when the xylem and phloem make special tissue called bark and
wood .. We usually find this type of tissue in trees.
The phloem makes bark on the outside of a stem.
The xylem makes wood as the stem grows bigger around.
Different growing seasons allow different amounts of wood to
form. As a result we can count the age of a tree by counting its
annual rings. These are the circles you see when a tree is cut
down. Each of the circles represents a year of growth.
TRY THIS: Count the number of growth rings in this tree.
How old is the tree?
LOOK AT some of the bark on the table. Why do you think trees
die if a rabbit eats all of the bark off of the bottom of the stem?
(YOUNGER GRADES MAY WANT TO MAKE BARK
RUBBINGS)
Table 2: Leaves are the parts of a plant that carry out most of the
photosynthesis. So they help to make the food for the plant.
Leaves can have many different shapes. The margins of leaves can
be different too.
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2004
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TRY THIS: Look at the leaf models on the table. Fill in the chart
to describe the different leaves.
(YOUNGER KIDS MAY JUST WANT TO GROUP SIMILAR
LEAVES TOGETHER)
Some leaves do NOT look broad and flat. Some leaves have
modifications. Look at the plants on the table. How are these
leaves modified?
Table 4: Flowers can be very beautiful parts of plants or they can
be fairly drab. An example of a beautiful flower would be a rose.
A drab flower might be the flower on grass! (Yes, grass has
flowers!). The group of plants that produce flowers are called
Angiosperms.
(
Flowers have an important purpose for the plant. They form seeds
so that new baby plants can grow from them. So flowers allow the
plant to reproduce.
There are many different kinds of flowers. Study the diagram on
the table to see some of the different types of flowers. Most
flowers have certain basic parts that are important in forming the
baby plant inside the seed. Look at the picture of the flower parts
on your table.
TRY THIS: Take a flower and see if you can find all of its parts.
Draw a picture of what you see on the white board.
(TEACHERS PLEASE FEEL FREE TO REMOVE A COUPLE
OF LIVE FLOWERS FOR YOUR CLASS TO LOOK AT
CLOSEL Y)
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2004
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Some plants do NOT produce seeds in flowers. Instead they
produce seeds in cones. This group of plants are called the
Gymnosperms. Although there are many different kinds of
gymnosperms some of the ones we commonly see are the plants
that stay evergreen ... that is they stay green all year round! So
trees that you might use for a Christmas tree are probably
gymnosperms (firs, pines, cedars etc.)
Let's take a look at some different cones. Look carefully at the
gymnosperm cones on the table. Do you see a seed? Do you think
all cones are the same size? Do big trees always have big cones?
Table 5: Once a seed has formed, a baby plant (a plant embryo)
starts to develop in the seed. This baby plant has a tiny, little
beginning of a root, an eensy-weensy beginning of a stem, and
very small leaf starts.
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2004
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The parts of the embryo are as follows:
• Cotyledon: This is a source of stored food for the
developing baby plant (embryo)
• Seed Coat (testa): The is the tough outer coat of the
seed
• Embryo: The baby plant
• Radical (embryonic root): The part of the embryo that
becomes the root
• First Leaves: The part of the embryo that become the
leaves
TRY THIS:
1. Remove a bean seed that has been soaking in water.
2. With your fingernail, carefully remove the seed coat.
3. Separate the cotyledons and examine the embryo.
4. Draw and label what you see.
Does the seed divide into 1 cotyledon or 2?
Seeds that have 2 cotyledons are called dicotyledons or dicots.
Seeds, such as com, that only have one cotyledon are called
monocotyledons or monocots.
Seeds that are produced by Angiosperms in flowers can be found
in a fruit. So a fruit is any plant structure that contains a seed.
Look at the plant parts on the table. Are these fruit or vegetables.
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2004
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Vegetables would be any plant part that we eat that does NOT
have a seed.
(ANYTHING WITH A SEED IS A FRUIT! EVEN TOMATOES,
CORN AND BEANS!)
'--........-.
Different fruits have different shapes and different ways of
moving seeds around (dispersal mechanisms) so that they can be
planted in different places. Some common fruit types are:
• Follicles: Dry fruit that splits along one side.
• Legumes: Pods that split along 2 sides (beans).
• Capsules: Pods that split in various ways or that
"sprinkle" seeds out like salt shakers.
• Achenes: Small fruits where seed nearly fills the seed
coat but doesn't stick to fruit wall. (sunflower_
• Grains: Much like achenes except the seed coat does
attach to fruit wall
• Samaras: Fruit that are equipped with wings
• Nuts: Non-splittting, hard bony fruits containing one
seed.
• Berries: A fleshy, juicy fruit
• Drupe: A fleshy fruit containing a pit or hard stone
• Pomes: A special type of fruit that contains different
tissue types (apple)
Seeds can be dispersed by different mechanisms.
• Wind: Some fruit have parachutes or wings to move
seeds
• Water: Some fruit can float or have seeds that are
splattered by water
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2004
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• Sticking to animals: Some seeds can attach to animal
fur or socks
• Released in animal poop: Yep! Some animals eat
seeds and then poop them in another location.
• Ca!Tied by animals: Some fruits are carried around and
even buried by animals (squirrels)
TRY THIS: Look at the different fruit types on the table and fill
in the chart.
(YOUNGER KIDS MAY JUST WANT TO GROUP SIMILAR
FRUITS TOGETHER. BE SURE TO TALK ABOUT
DIFFERENT WAYS SEEDS ARE DISPERSED!)
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2004
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