From Seed to Seed:
Plant Science for K-8 Educators

Activity 23: An Eye for an... Plant???

Grades: K-4

Associated Lesson Topics:

• Underground stems
• Asexual propagation
• Solanaceae (nightshade or potato) family
• Liliaceae (lily) family; garlic is a member
• Plant parts as food

National Standards:

• SCIENCE: Standard A, Standard C
• GEOGRAPHY: Standard 1
• HISTORY: Standard 1a, Standard 2b, Standard 8

Planting the Seed...

Where do you think new plants come from? Do all plants grow from seed? Can you imagine any other ways that a new plant might grow? How do you think grass grows? Do you really have to plant a grass seed in every single spot in the soil if you want a full lawn?

Teacher Information:

There are two ways that plants can reproduce. In sexual reproduction, the union of gametes results in seed production, whereas, in asexual reproduction, an identical replica of the plant is produced through the propagation of plant parts. Plants with rhizomes (iris), bulbs (garlic), tubers (potatoes) and corms (crocus) reproduce asexually, or vegetatively. The purpose of this activity is for students to explore asexual reproduction in tubers and bulbs.

Tubers are actually enlarged underground stems whose primary purpose is storage. The "eyes" that we see on potatoes are actually buds that will form new shoots. Bulbs are also dormant underground stems that can reproduce asexually. Garlic is an example of a bulb. New roots and new bulbs will grow from the base of a garlic bulb.

Necessary Materials:

• Potatoes that have already begun to sprout.
• Knives.
• Drinking glass-large enough to hold your potato standing on end.
• Toothpicks.
• Garlic.
• Large, transparent plastic drinking cup with lid.
• Planting materials.

Procedure (Tubers):

Outside in the garden...

• Plan to plant your potatoes in early spring.
• If you can't find potatoes that have already begun to sprout, place some in a warm spot to encourage sprouting.
• When the potatoes begin to sprout, have students cut them into pieces. In order to produce new potato plants, each piece must have at least one "eye" in it. Invite students to experiment with the size of the potato piece. For example, how small can a potato piece be and still produce a new plant?
• Plant each potato piece a couple of inches deep and space them 8 to 12 inches apart. The new tuber will grow above the piece you plant. Plant enough potato pieces so students can remove them from the soil at regular intervals and make observations. Keep the soil moist but not drenched. Watch for new potatoes!
  
  
  

In the classroom...

Some classrooms have successfully raised potatoes in 5-gallon buckets. Your students can also explore asexual reproduction in the classroom by following this procedure:

• Find potatoes that have already begun to sprout or place potatoes in a warm spot to encourage sprouting.
• Fill a glass with enough water to cover the bottom of the potato.
• If you imagine the diameter of the potato to be a clock, insert toothpicks into the potato at its widest point at 12:00, 3:00, 6:00, and 9:00.
• Place the potato into the glass with the toothpicks resting on the rim of the glass.
• Place the glass in a lighted place, but not in direct sunlight. Keep adding water to keep the level consistent.
• After about three days, roots will begin to develop and after about six days, a shoot will begin to grow out of the top!
  
• In approximately 80 days, you can dig up your potatoes.

Procedure (Bulbs):

Outside in the garden...

• Buy garlic from the grocery store and have students separate the cloves.
• Plant the cloves with the flat end down (or have students experiment with which end is up) about three fingers apart and 2 inches deep. It is best if the soil is slightly sandy.
• Water regularly.
• Be patient and soon you will see a new plant shooting up out of the ground.

In the classroom...

• Buy garlic from the grocery store and have students separate the cloves.
• Each student will need a plastic drinking cup with a lid. Cut a hole in the lid large enough to hold the garlic clove in place.
• Fill the container with water so that the bottom of the bulb will be submerged.
• Place the garlic clove in the lid and place the lid on the container. Place on windowsill. Within a week, students should be able to see shoot and root growth.
  

Harvesting the Crop...

Now that students have tried planting things other than seeds, have them suggest other plant parts they think might generate new plants. What have you observed that led you to this prediction? How do you imagine a new plant will be produced from this part? Invite them to test their suggestions.

Alternatively, students can explore how other cultures use potatoes and garlic or how these plants have played a role in societies throughout history. They both have fascinating resumes! Potatoes were, after all, a staple food in Ireland for a very long time. Did Native Americans have any special uses for these foods?

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