Grades K–2 · Organisms
How does a seed become a young plant?
A dry bean looks like a little pebble. Yet inside its coat is a tiny young plant, with food packed around it. That food helps answer a puzzle: how can the plant begin growing before it has any leaves?
When a living bean seed has water, air and suitable warmth, it can begin to sprout. Water enters and the seed swells. The young plant starts using its stored food. Soon a small root breaks through the coat and grows down into the moist ground.
The root takes in water and helps hold the plant in place. A curved shoot pushes upward. In a bean plant, it lifts the two thick seed leaves out of the ground. They carry some of the food that helped the plant get started.
Follow the bean from top to bottom: its food is already inside before a root or a green leaf appears.
New green leaves open above them. Now light helps the leaves make more food for growth. The little plant has changed from using a packed meal to making its own food. What looked like a pebble was the beginning of roots, stems and leaves.
About this explanation
These are bean seedlings. Other kinds of seeds can sprout in different ways and at different speeds.
Starting knowledge: Recognize a seed and compare earlier and later pictures.
Sources
- Next Generation Science Standards — Kindergarten: observing the needs of living things
- University of Minnesota — Seed physiology and external germination conditions
- University of Minnesota Extension — Starting seeds indoors
- University of Minnesota — 2.2 Introduction to Seed Germination — The Science of Plants