BIOLOGY [3 marks Question Answer]

1. Testa (seed coat)
2. Plumule
3. Radicle
4. Micropyle
5. Cotyledon

1. Testa (seed coat) — It protects the seed from insects and bacteria as well as from a mechanical injury.
2. Plumule — Plumule develops into a shoot.
3. Radicle — Radicle develops into a root
4. Micropyle — The micropyle absorbs as much water as is required for germination.
5. Cotyledon — Contain stored food material which is used by the seeding during germination.

If all the seeds produced by a plant happen to fall under the same plant and sprout into new plants then in this situation plants will face the following problems:

1. A large number of plants will grow in a small limited space. The water and the minerals available to them in the soil will be limited.
2. The air surrounding them will not be enough and less sunshine will be available to them. As a result, most of these sprouted plants will die.

Seed coat

1. It is the protective covering of the seed.
2. It develops from the protective layer around the ovules.
3. The seed coat determines the shape of the seed.
4. Water diffuses through the seed coat into the embryo causing swelling of seed and rupturing of seed coat during germination.

Embryo

1. It is the young plant enclosed within the seed coat which germinates to form a new plant.
2. It is a product of fertilisation inside the ovary
3. Embryo just fills in the shape determined by a seed coat.
4. It consists of a radicle, plumule, and cotyledons which give rise to the root and shoot system of the plant.

Dicot seed

1. The dicot seed has two cotyledons.
2. The endosperm is absent.
3. The seed coat is not fused with fruit wall.
4. Examples: bean, pea, gram.

Monocot seed

1. Monocot seed has one cotyledon.
2. The endosperm is present.
3. The seed coat is fused with a fruit wall.
4. Examples: rice, maize.