A bean seed grows quickly into a bean plant. It is one of the fastest growing plants. After the bean is planted in the soil, it takes only a week for it to germinate. The bean plant is fully grown in six weeks. Its seeds drop into the soil or are planted there, and the life cycle begins again.
Germination is the first step in the life cycle of a bean. It is the stage of the life cycle when the seed begins to grow. This occurs after the bean is planted and is watered. A sprout appears on the bean and begins to grow upward. This sprout is called the hypocotyl. The part of the sprout that grows downward is called the root.
The hypocotyl, or shoot, grows until it reaches the surface of the earth. It breaks through the soil and becomes a sprout. As the sprout is exposed to the sun, it continues to grow and becomes a seedling. It needs sunlight, air and nutrients from the soil to grow.
Six weeks after the bean was planted, the seedling becomes a young adult plant. Flowers then grow on the young adult. The flowers become the bean seeds. The beans have many seeds inside. The beans are picked, and the development of the bean plant is complete. Some of the seeds fall to earth on their own, or are dropped there by birds or other animals. A new plant grows from these seeds, and the life cycle begins again.
Several vocabulary words exist that are helpful in understanding the life cycle of a bean plant. The bean plant is a dicot, or a flowering plant with two cotyledons. Cotyledons are the tiny leaves within the seed. The embryo is the developing plant still inside the seed.
The seed coat is the outer covering of the seed. It protects and nourishes the embryo. The hilum is the scar on the seed coat in the spot where it was attached to the stalk. The micropyle is a small opening in the seed that allows it to absorb water. The root is the part of the stem of a sprouting plant that grows downward. The shoot, or hypocotyl, is the part that grows upward.