Page 8 - Future Stars Science Explorer-5

Brainy Bites
Brainy Bites
Structure of a Seed Brainy Bites
If we eat an apple or an orange, we will • Coconut is a seed.

find seeds inside. New plants can grow • A single plant like sunflower can
produce over 1000 seeds.
from these seeds. The structure of a bean
seed is shown below.

An outer covering
called the seed coat Embroyonic roots
protects the baby
plant inside the seed.
Seed leaves or cotyledons
The seed coat has a store food for the baby plant.
tiny hole through
which the seed gets
water. Embroyonic leaves
Outside Inside
Structure of a bean seed

Seeds of flowering plants have one or two cotyledons. A cotyledon is also
called a seed leaf.

Plants that produce seeds with two cotyledons are called dicotyledonous-

plants or dicots. Bean, mango, and apple are examples of dicotyledonous

plants.

If we soak a dicot seed, such as a bean seed, in water, we can separate the two
cotyledons and see a tiny structure attached to the cotyledons. This is the baby

plant or the embryo. It can grow into a new plant.

Some plants produce seeds with only one cotyledon. Such plants are called

monocotyledonous plants or monocots. Maize, wheat, grass, and paddy
(rice) are monocotyledonous plants.

Germination of a Seed

The growing of a baby plant from a seed is called germination.

When the seed gets the right conditions to grow, it starts germinating. The seed
must get water, air and warmth to start germinating. The seed absorbs water,

swells up and the seed coat becomes soft. The cells in the baby plant become
active and start to grow. The roots of the germinating plant appear first and they

grows down into the Earth. Then the shoot appears and grows upward toward

8 Science-5