Download Plant Parts and Their Functions

Grade: K to 2
Length: one hour or two, 30-minute sessions
Subjects: life science, art, health
Topics: identification of plant parts and their
functions, introduction to weed adaptations
Objectives
Exercises in this lesson help students achieve the
following objectives:
Identify parts of plants (flowers, leaves, stems,
roots) on diagrams of weeds and live weed
specimens
Identify plant parts in common foods
Describe the function of plant parts
Recognize and explain how the form and
function of parts of weeds provide weeds with
adaptive advantages over other plants
Introduction
Most plants are quite literally rooted to their environments. Plants have developed a wide range of
adaptations suitable to a sedentary lifestyle. Parts
of plants are designed to capture the sun’s energy
and convert it to food, obtain and conserve water,
protect the plant from animals that might eat it,
ensure propagation, withstand a range of climatic
conditions, and compete with other plants for
resources.
Students will learn the name and function of parts
of plants. This knowledge establishes a common
vocabulary and serves as the basis for future lessons that teach adaptive advantages of weeds,
identification of weeds, consequences of weeds’
invasive nature, and effective control strategies.
Before teaching this lesson, read the entire lesson
and make sure all materials are available.
Background
Share the following information about parts of
plants with students. Adapt the amount of detail
to the age, interest, and ability of students. Provide
students with illustrations of plant parts (optional).
(For illustrations, see the lesson From Seed to Shining Seed.)
Plants vary greatly in size and shape, but most
plants have the following parts:
Leaves – Consist of a blade or lamina, midrib,
veins, and a petiole or leaf stalk. Some leaves,
such as those on a heather and a pine tree’s or
cactus’s needles, are highly modified. Stems and
leaf veins contain water carrying tubes (xylem) and
sap carrying tubes (phloem). The xylem tissue is
in the center, and the phloem is arranged around
the xylem. The upper surface of a leaf consists of a
waterproof cuticle. The lower surface of a leaf has
stomata. Stomata are ventilation holes that take
in carbon dioxide and give off oxygen, the gases
of respiration. Leaves are the food factories for a
plant. Leaves contain chlorophyll, which converts
the sun’s energy to food through the process of
photosynthesis. Leaves are usually broad and arranged to maximize the capture of energy from the
sun.
Stems – Provide structure, carry water from the
roots to the rest of the plant, and carry food from
the leaves to the roots. On many plants, stems also
photosynthesize and exchange gases for the plant.
Roots – Are generally hidden in the soil. Roots
provide plants with minerals and water. Roots are
covered with many tiny hairs (root hairs), which
increase a plant’s ability to take in water. Only the
tip of a root grows. The tip of a root that pushes
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through the soil is covered by a tough root cap.
Xylem (water carrying tissue) and phloem (sap carrying tissue) run through roots, with xylem in the
center, and the phloem arranged around the xylem.
Flowers – Contain the following reproductive
organs:
Pistil - female part; includes the ovary, style,
and stigma
Ovary - expands after fertilization and forms
the seed or fruit
Style - stem-like extrusion of the ovary (A pollen tube extends from the style into the ovary
and carries the pollen needed for fertilization.)
Stigma - top of the style (The stigma is sticky,
and it collects pollen.)
Stamen - male part, includes the filament and
anther
Filament - stalk-like part
Anther - tip of the filament, holds the pollen
When wind, an insect, or a small animal carries the
pollen to the stigma, pollination occurs. After fertilization, the petals of the flower wither while the
seeds grow and accumulate food reserves to nourish the embryo plants inside. The petals are usually
bright colors to attract pollinators. Petals form a
ring or corolla around the reproductive parts. Outside the corolla, the green sepals make up the calyx
or outermost part of a flower.
Adaptive advantages of weeds
Parts of weeds often have special adaptations
that enable weeds to spread or out-compete other
plants. Examples of special adaptations include
fast-growing parts, flowers that create millions of
seeds annually for each plant (purple loosestrife),
and roots that grow extra long. (Roots of leafy
spurge can grow over 17 feet long.) To explore
these adaptations in greater depth, see the lesson
The Great Race for Survival.
Preparation
Materials
eight, large-size post-it notes
potted plant or weed specimen
the words head, hand, leg, chest, flower,
1 Print
leaf, stem, and root on eight, large-size post-it
notes.
a student volunteer to stand at the front of
2Ask
the room.
another student to come forward and
3Ask
place the post-it notes with the words head,
hand, leg, and chest on the correct part on the first
student.
the second student places the post-it
4While
notes, briefly describe the purpose of each part.
For example, “The head protects the brain, which
serves as the control center for the body. Through
the mouth, which is part of the head, we take in
food, and food provides energy to the body. The
mouth also allows us to communicate with others.”
Make a similar statement for the function of hand,
leg, and chest.
a student to similarly label the parts of a
5Ask
potted plant or weed specimen using the postit notes with the words flower, leaf, stem, and root.
Briefly introduce students to the function of these
parts while the student places the post-it notes.
Activity
Materials
Diagram of a Typical Plant and Flower Structure
worksheets – Have available one copy for each
student.
the worksheets that have parts of plants
1 Using
labeled, show students the Diagram of a Typical
Plant and Flower Structure. Discuss parts and their
functions. Discuss all parts or some, depending
on the age and ability of students. Or draw the
illustrations on the chalkboard and label the parts.
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each student a copy of the weed
2Give
worksheets that have no parts labeled.
students to identify the parts in one of the
3Ask
following ways, depending on the age and
part. Glued-on parts will create a mosaic effect, and the exercise reinforces the connection
between diagram and live specimen. Plant parts
from live specimens are fragile. For best results,
apply a glue stick to the illustration, then gently
press the plant part directly onto the tacky
area. When students have finished, have them
hold up their work, name the weed parts, and
describe their functions.
ability of students:
Have students point to a part and name the
part verbally. Conduct this exercise as an entire class or in small groups.
Write the name of each part on the worksheet.
Working with live specimens or three-dimensional models, have students draw a weed and
label its parts. Instruct them to look very closely
at the live specimen or model, as if they were a
bee crawling all over it to investigate. Suggest
that students attempt to fill the entire page with
their drawing. Show students some of artist
Georgia O’Keefe’s beautifully detailed, close-up
paintings of flowers, and share the following
quote with them:
Conclusion and Evaluation
Conclude the lesson by reviewing parts of a
weed and the function of each part. Suggest
that some parts of a weed often reflect special
adaptations that enable weeds to spread or outcompete other plants. For example, some weeds
have fast-growing parts, flowers that create millions of seeds annually per plant (purple loosestrife), and roots that grow extra long. (Roots
of the weed leafy spurge can grow over 17 feet
long.)
Evaluate students on their participation in class
discussions and the completeness and accuracy
of their weed illustration, including a thorough
identification of weed parts and an explanation
of their functions.
Independent Practice and Related
Activities
Have students color their weed illustration using pigments from live plant specimens. To color with live plant pigments, rub the appropriate
plant part onto the illustration. For example,
rub leaves onto leaf areas of the illustration and
petals onto petal areas. Friction with the paper
will break down the organic material, and the
pigments will bleed directly onto the paper.
Remove organic residue by lightly brushing
the surface of the paper with your fingertips.
Discuss the function of plant pigments.
Have students dissect or pull apart live weed
specimens. If possible, use the same specimen
shown in the illustration. Glue stems, roots,
leaves, and flowers directly onto the illustrations within the appropriate margins for that
“A flower is relatively small. Everyone has
many associations with a flower – the idea of
flowers. You put out your hand to touch the
flower – lean forward to smell it – maybe touch
it with your lips almost without thinking – or
give it to someone to please them. Still – in a
way – nobody sees a flower – really – it is so
small – we haven’t time – and to see takes time,
like to have a friend takes time. If I could paint
the flower exactly as I see it no one would see
what I see because I would paint it small like
the flower is small. So I said to myself – I’ll
paint it big and they will be surprised into taking time to look at it – I will make even busy
New Yorkers take time to see what I see of
flowers.” – Georgia O’Keefe
Prepare small bowls with a selection of edible
plant parts, such as celery, carrots, fresh spinach leaves, radishes, broccoli florets, pumpkin,
and sunflower seeds. Ask students to identify
each food as a leaf, root, stem, flower, or seed
and name its function. Students should share
plant-part snacks by asking for a plant part
name, not common name. For example, “Please
pass the stems,” or “Please pass the orange
roots.”
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Vocabulary
adaptation, flower, form, function, leaves, pigment,
root, stem
Resources
Proctor, John, and Susan Proctor. Color in Plants and
Flowers. New York: Everest House, 1978.
Spellenberg, Richard. National Audubon Society Field
Guide to North American Wildflowers, Western Region.
2nd ed. New York: Knopf, 2001.
National Science Education
Standards
As a result of their activities in grades 5 to 8,
students should develop abilities in and an understanding of the following areas:
Life Science – Content Standard C: characteristics
of organisms, life cycles of organisms, organisms
and environments
For three-dimensional models of weed specimens,
contact the Center for Invasive Plant Management,
733 Leon Johnson Hall, MSU Bozeman, P.O. Box
173120, Bozeman, MT 59717-3120; 406-994-6832.
[email protected], www.weedcenter.org
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Diagram of a Typical Plant
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flower
root
bud
stem
leaf
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petal
stigma
style
ovary
anther
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