WHAT’S IN
A SOYBEAN?
Seed Germination & Disection Activity
What are these?
Soybeans!
How are they used?
Let’s Take a Field Trip to Learn More!
Let’s See What’s Inside a Soybean!
Germination & Dissection
What Does a Seed Need to Germinate?
Water, air, and the right temperature tells the tiny plant inside the seed to start growing.
We need a place for the seed to sprout. Plants use soil to anchor their roots, and soil holds water and nutrients the seed needs to grow.
While soil is not required for all plants to grow, it is a good place for a soybeans to grow on a farm.
Place the paper towel in your bag to be like soil. It will hold the water.
SOIL
Now place a seed in your bag on top of the paper towel.
Seeds contain the tiny plants that are waiting for the right conditions to germinate into a new plant that will make more seeds. This is how a plant reproduces.
SEED
Add a sun to your bag.
The sun warms the soil to the right temperature. A soybean needs its surroundings to be at least 54ᐤ F. That is why many farmers wait to plant their soybeans until mid to late spring.
What is the current temperature?
WARMTH
Just like you need vitamins to be healthy, plants need vitamins to be healthy, too. The vitamins, or nutrients, are found in the soil, air, and water for the plant to use.
Add confetti to your bag for the nutrients.
NUTRIENTS
Water softens the seed coat and tells the tiny plant inside the seed to grow.
Add water to your bag - but just a little. If it gets too wet, the seed will get too soft and won’t grow.
Plants, just like humans, are made mostly of water.
WATER
Plants need air just like we do! Air in the soil gives the plant room to break out of it’s seed coat.
Once the plant breaks out of the soil, it will use the air to grow.
Blow into the bag to make sure your seed has air.
AIR
WAIT AND WATCH!
Can you tell a friend what a seed needs to sprout?
Video – Bean Seed Time Lapse
Seed Structures
Parts of a Soybean Seed
The soybean seed is made up of a tiny plant embryo (leaves and roots), a food source for the embryo (cotyledon), and a tough outer covering called the seed coat.
Soybeans also have a hilum, the place where it was attached to the seed pod. If you look carefully, you may also be able to see the micropyle just under the hilum. This is where water first enters the seed, and triggers germination.
Hilum
Seed coat
Embryo
Food Source (Cotyledon)
Micropyle
Parts of a Corn Seed
The corn seed also includes endosperm, which made mostly of starch. The endosperm provide another food source for the young plant, and is a key part of seeds known as grains.
Parts of a Pine Nut Seed
Structures Change �as the Seed Germinates
Radical (Root)
Hypocotyl (Stem)
Cotyledon (Food Source)
Seed Coat
Embryo
Hilum
Micropyle
Epicotyl
(Leaves)
Hypocotyl (Stem)
Radical (Root)
Epicotyl
Detailed structures of a germinating soybean seed
How Does a Seed Germinate?�Dicotyledon
Moisture causes the seed to swell and the seed coat softens.
Root (radical) emerges and grows downward.
Root begins to branch and stem (hypocotyl) emerges to push through the soil.
Seed coat breaks off and cotyledons emerge.
First leaves (epicotyl) emerge from cotyledons
Seedling will continue to grow with the right conditions.
Monocots and Dicots
Plant Classification Based on Seed Structures
Dicot
2 Leaves
Monocot
1 Primary Leaf
(looks similar to grass)
Monocot or Dicot
Corn
Monocot or Dicot
Tomato
Monocot or Dicot
Geranium
Monocot or Dicot
Wheat
Monocot or Dicot
Daylily
Monocot or Dicot
Soybeans
Monocot or Dicot
Fescue
Monocot or Dicot
Squash
Answer Key
Monocots
Corn
Wheat
Daylily
Fescue
Dicots
Tomato
Geranium
Soybeans
Squash