Parts of a Seed

Author

Kristi Harmeier

Published

1/7/2017

Topics:

Lesson Plans - 3rd - 5th

Target Grade Level / Age Range:

4 ^th grade

Time:

45 minutes

Purpose:

Students will learn about two types of plants and the parts of their seeds, using Iowa corn and soybeans as examples.

Materials:

Corn seeds
Soybean seeds
Variety of edible seeds
Pencils
Crayons

Suggested Companion Resources (books and websites)

How A Seed Grows by Helene J. Jordan

Vocabulary (with definitions)

seed coat – covers and protects the seed
embryo – forms the new plant
endosperm – acts as food for the seed, and nourishes the embryo
germinate – when a seed begins to grow, or puts out shoots
cotyledon – the first “leaves” of a plant
monocot – a plant with one cotyledon
dicot – a plant with two cotyledons

Background – Agricultural Connections (what would a teacher need to know to be able to teach this content):

This lesson dives into the anatomy of seeds, as well as how seeds differ between monocot and dicot.

Monocot:
- The term monocot is short for monocotyledonous. This simply means that the plant has one cotyledon. A cotyledon is the plant’s first leaf.
  - Cotyledon is pronounced like cot-ill-E-don.
- Monocots are grasses. They have long, thin leaves instead of broad, or palmate leaves. The veins in the leaves are usually parallel. There are also differences in roots, stem, and flower development between monocots and dicots.
- An example of a monocot would be corn. When corn germinates, the roots emerge from the bottom of the kernel, and the cotyledon emerges from the top. This is called epicotyl emergence.
Dicot:
- The term dicot is short for dicotyledonous. This means that the plant has two cotyledons.
- Dicots are broadleaf plants. Their leaves can be interesting shapes, and will have more webbed veins in the leaves. Dicots tend to have taproots instead of fibrous roots.
- An example of a dicot would be soybeans. When soybeans germinate, the seed actually ends up above ground. The root shoots from the seed, the hypocotyl elongates and forms an arc, which projects the seed and the cotyledons above the ground. This is called hypocotyl emergence.
  - Soybeans are a non-endospermic dicot. This means that its cotyledons act in the same way as the endosperm does in other seeds (food storage for the embryo). Cotton would be an example of a dicot seed that contains an endosperm.

The student worksheet takes a relatively simple version of all of this information. The main goal of the worksheet is to help students understand that there are two types of plants, and that there are parts within the seed that help it to grow.
- The students will need to know:
  - Common Iowa crop representatives of monocots and dicots (corn and soybeans)
  - How to identify three main parts of each seed
    - In corn:
      - Endosperm, cotyledon, and embryo
    - In soybeans:
      - Seed coat, cotyledon, and embryo
- When working through the worksheet, talk with students about the function of each part of the plant. Students may not remember what a cotyledon is, but if they remember that some plants start with one leaf and others start with two, that is good.
  - After students label the parts of the seed on page 2, it could be possible to go through as a class and write a short description of what that part does.
Seed germination requires only moisture and heat.
- Though this lesson doesn’t directly include a germination lab, one could easily follow. Students could use one corn seed and one soybean seed and watch as the parts of the seed they once identified germinated and began to grow.
  - Water beads or orbeez and a jewelry sized Ziploc bag create a good environment for seeds. Ensure that the seeds are placed in a warm place, and they should germinate. After about a week, the seed will need to be planted in soil in order for it to continue to grow.
Corn and soybeans have a variety of uses.
- Most of these crops go to feeding livestock, like hogs and cattle. However, corn can also be made into ethanol, sweeteners, or even fibers in yarn and carpet, or biodegradable packing peanuts and plastic! Soybeans can be made into soy biodiesel, tofu, vegetable oil, or the foam in car seats!
- Both corn and soybeans are planted in the spring and harvested in the fall. For the most part, the same equipment can be used for both crops. However, the header, or front attachment on the combine, must be changed if a farmer needs to harvest these two crops.
- The animals that the corn and soybeans feed help give back to the farmland though the nutrients in their manure. This can be used as a cheap and valuable fertilizer for crop ground.
  - Manure isn’t applied carelessly, however. There are regulations dictating times, temperatures, and amounts allowed for applying certain types of manure.
  - Farmers can also test their soils for the amount of nutrients in them, as well as the manure they plan to apply. This way, farmers can calculate exactly the needs of the field, and not over apply nutrients.

Interest Approach or Motivator:

Ask students what they think are inside of seeds. Do seeds hatch like eggs? What do they need to grow?

Procedures

Introduce the class to seeds by showing both corn and soybean seeds. Ask students what they are and why they might be important. Ask students to list a few examples of items that contain corn and soybeans.
1. Ethanol, biodiesel, pop, vegetable oil, candy, car seats, carpet, the list could go on!
Read the story How a Seed Grows.
1. Read and discuss the parts of a seed and the life cycle. Discuss why seeds are important to us. How do seeds connect to farmers? What seeds to local farmers need a lot of? Talk about how Iowa farmers raise lots of corn and soybeans.
Tell students they will get to learn about the inside of seeds!
Display the pictures in the Monocot vs. dicot germination photos PDF. Explain to students the difference between monocot plants and dicot plants.
1. Point out that there are many parts of a seed, but don’t dwell on those details too long.
2. Once the students have a basic knowledge of the two types of plants, direct them to their worksheet packet.
Have students look at the first page of their worksheet. Answer the first 2-3 questions together as a class. Ask students if they have seen corn or soybeans growing. Have they seen corn or soybean seeds before class today?
Direct students to work on the second page in their seed booklet. Walk around and answer questions as necessary. Tell students to reference the first page if they get stuck.
Next, hand out one corn seed and one soybean seed to each student. It may be beneficial to have them split previous to class time.
1. Tell students to look for parts of the seed. Display one of the more intricately labeled diagrams on the board or projector screen during this time. Encourage students to look for as many parts as they can.
2. Instruct students to draw their own diagrams of their seeds on the third page, and label the parts they can see.
If possible, let students eat some seeds! Have available corn, soybeans, sunflowers, edamame, pumpkin seeds, peanuts, chickpeas, cowpeas, cashews, or other seeds. Talk about how each seed is different, and about how farmers raise some crops for the seeds, or they plant seeds to harvest other parts of the crop.

Essential Files (maps, charts, pictures, or documents)

Did you know? (Ag facts)

Iowa is the #1 state in both corn and soybean production.
One of the first hybrid seed producers was an Iowan named Henry A. Wallace.
Most of the corn in Iowa is field corn (99%). The remaining 1% is split between sweet corn, popcorn, and decorative or Indian corn.
A typical ear of corn has about 800 kernels!
Soybean pods generally contain 3-4 soybeans. Each plant can have about 50 pods.

Extension Activities (how students can carry this beyond the classroom)

Assign students to find 12 seeds outside of class time. Give each student an egg carton and instruct them to put their different seed types in their egg carton. Tell them to label what plant the seed came from if they can.
Follow up with a germination lesson using a monocot and a dicot to display the differences between the two. IALF’s Seed Germination Necklace lesson https://youtu.be/QJMoxGwwzFs would fit in well.

Author(s)