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seed labeled

Parts of a Seed

Target Grade Level / Age Range:

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?

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

Seed labeled

The outer covering of a seed is called the seed coat. Seed coats help protect the embryo from injury and also from drying out. Seed coats can be thin and soft as in beans or thick and hard as in locust or coconut seeds. Endosperm, a temporary food supply, is packed around the embryo in the form of special leaves called cotyledons or seed leaves. These generally are the first parts visible when the seed germinates.

Plants are classified based upon the number of seed leaves (cotyledons) in the seed. Plants such as grasses can be monocots, containing one cotyledon. Dicots are plants that have two cotyledons.

The Great Plant Escape is an elemertary plant science program for 4th and 5th grade students. Each of the lessons in this program is interdisciplinary, designed to introduce students to plant science and increase their understanding of how food grows.