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14. Reproduction eLearn.Punjab
Seed germination is a process by which a seed embryo develops into a seedling. During germination,
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.
On the basis of the elongation of hypocotyl and epicotyl, there are two types of germination (Fig.
14.18). In epigeal germination, the hypocotyl elongates and forms a hook, pulling the cotyledons
above ground. Beans, cotton and papaya are the examples of seeds that germinate this way. In
hypogeal germination, the epicotyl elongates and forms the hook. In this type of germination, the
cotyledons stay underground. Pea, maize and coconut germinate this way.
Figure 14.18: Types of seed germination; epigeal (left) and hypogeal (right)
Most seeds go through a period, during which there is no growth. This period is called the dormancy of
the seed. Dormant seeds are ripe seeds but do not germinate. Under favourable conditions, the seeds
break dormancy and begin to germinate
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