Baby Plant: What Does the Inside of a Seed Look Like?
What does the inside of a seed look like?
- 10 pinto beans
- Baby food jar
- Tap water
- Paper towels
- Magnifying lens
- Place the beans in the baby-food jar.
- Fill the jar with water.
- Place the jar in the refrigerator overnight.
- Use the spoon to remove the beans from the jar.
- Place the beans on a paper towel to absorb the excess water.
- Use your fingernail to carefully remove the outer covering from one of the beans.
- Use your thumbnail to pry the round end of the bean open. Separate the two halves of the bean very gently so as not to break the inner parts. If the inner parts of the bean are broken, repeat steps 6 and 7 with another bean.
- Lay the two halves of the bean on a clean paper towel, with the inside of each bean half facing up.
- Use the magnifying lens to study the structure of each bean half.
- Use the diagram on the next page to find each of these parts on your bean: cotyledon; epicotyl; hypocotyl; radicle.
What appears to be a baby bean plant is found inside the bean.
Within every seed are basic structures that will develop into a plant. The function of each of these structures is described on the next page.
- Epicotyl—Forms the first true leaves of the plant.
- Hypocotyl—Forms the lower stem and roots.
- Radicle—Tip of the hypocotyl which develops into the main root of the plant.
- Cotyledon—Stores food for the young plant until it can make its own food. A bean is a dicotyledon, commonly called a dicot, because it has two cotyledons.
In many plants, when a seed is first formed it is not ready for planting. It must first go through a dormancy period (time of inactivity). The seed does not grow during its dormancy period, but it does change chemically in order to prepare the baby plant inside for further development. After these chemical changes occur, the seed is ready to be planted—whereby germination (the beginning of growth or development) of the baby plant takes place within the seed. Germination can occur only if there is a proper amount of oxygen, water, and a suitable temperature. Each type of seed requires its own amount of oxygen, water, and warmth.
- Do other dicots have baby plants inside? Repeat the experiment, replacing the pinto beans with comparably shaped beans such as lima beans.
- Do monocots (seeds with one cotyledon) have baby plants inside? Repeat the original experiment, replacing the pinto beans with corn kernels, a common example of a monocot. Adult assistance may be needed to open a corn kernel.
Flowering plants are called angiosperms and are classified into two groups called dicots and monocots. Prepare a chart showing the differences between the two groups. Use the data chart above to aid you in finding examples of dicot leaves and flowers. Photograph the leaves and plants of each seed group and display the photographs on your chart. Use the microscope procedure below to study the location of the xylem and phloem (food-carrying) transport tubes in the stems of each group.
Try It With A Microscope
- Ask an adult to cut thin cross sections from the stems of a dicot and a monocot.
- Place the sections of stems on separate slides.
- Observe the stem sections under low power.
- Move the slides around to locate the thick-looking bundles of cells making up the transport tubes.
In the cross sections of each stem, the bundles of xylem and phloem tubes are seen as dark circles. In the dicot, all the circles are arranged in a ring around the stem. In the monocot, however, the circles are scattered randomly throughout the stem.
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