Question

What do you mean by seed ? Describe the process for formation a seed.

Answer 1

Seed is formed by development of ovule after fertilization. In an Angiosperms there is formation of a diploid zygote and a triploid primary endosperm cell by double fertilization. There is formation of endosperm from endosperm cell which provides nourishment to developing embryo. Then formation of embryo takes place from zygote. When embryo matures, its further development is suspended by growth inhibitors. There is reduction in protoplasm by the cell of Integument and formation of thick impermeable all/coat. In this way, formation of seed-coat takes place which outer part is testa and inner part is tegmen. The moisture inside seed reduces upto 10-15%, so it is called dormancy of seed. Then micropyle of ovule changes into seed micropyle and through its pore, O2 and water enter into seed during germination.