Question

Explain the stages of germination with the help of a diagram.

Answer 1

Hint:Germination is defined as the process during which a seed grows and develops into a new plant which resembles the parent plant from where the seed was originally produced.

Complete answer:
>The germination of seeds is affected by both external and internal factors. The external factors include water, temperature, oxygen and light. The internal factors include presence of the specific growth hormones as well enough nutrition. If any of the conditions are not right the seed does not germinate and enters into a state of dormancy. Germination takes place through a number of steps which are-
>At first the seed absorbs water that causes swelling and softening of the seed coat.
>During this stage the seed produces essential proteins and metabolises the stored food. This step is the lag phase of germination of seeds.
>Next the seed coat ruptures and the radicle emerges that goes on to form the primary root and the plumule that gives rise to the primary shoot.
>The portion of the stem above the cotyledon is called epicotyl and the portion below it is called the hypocotyl.
>This is finally followed by growth of the shoot and root tissues to give rise to the mature plant.

Note: Germination is mostly of two types- epigeal and hypogeal germination. Epigeal germination is where the cotyledon is seen to come above the soil surface and hypogeal germination is one where cotyledons remain below the soil surface.