Q9. Explain the germination of seed.
Answer:
Definition
Seed germination is a process by which a seed embryo develops into a seedling.
Process of germination
During germination, the embryo soaks up water which causes it to swell, splitting the seed coat. Root is the first structure that emerges from the radicle present in seed. It grows rapidly and absorbs water and nutrients from soil. In the next phase, plumule develops into tiny shoot which elongates and comes out of soil.
Types of germination
On the basis of elongation of hypoctyl and epicotyl, there are two types of germination:
(i) Epigeal germination .
In epigeal germination, the hypocotyl elongates and forms a hook pulling the cotyledons above the ground. Examples are beans, cotton and papaya.
(ii) Hypogeal germination
In this germination, the epicotyl elongates and forms the hook. In this type, the cotyledons stay underground. Examples are pea, maize and coconut.