Question

Write two significance of double fertilization.

Answer 1

Double fertilization, as the name indicates, involves two fusion processes and forms zygote as well as the structure that provides nourishment to the developing embryo. It is the characteristic feature of angiosperms.

Complete answer:
Two significance of double fertilization are:
-It gives rise to an endosperm that helps in providing nourishment to the developing embryo.
-It increases the viability of seed in angiosperms.

Additional information:
Double fertilization is a complex process that involves the fusion of one female gametophyte with two male gametes. During double fertilization, two types of fusion take place i.e., syngamy and triple fusion in the embryo sac. In syngamy, the haploid nucleus of one of the male gametes fuses with the haploid nucleus of the egg cell forming a diploid zygote (2n) that will further form the embryo after numerous cell divisions while in triple fusion, the haploid nucleus of the other male gamete fuses with the two haploid polar nuclei located in the central cell that will form a triploid primary endosperm nucleus (3n) that will form the primary endosperm cell and further, the endosperm. It is the most characteristic trait of angiosperms while in gymnosperms; it is a far more rudimentary form.
After double fertilization, the zygote develops into an embryo which derives its nutrition from the endosperm to develop into a mature seed. The stages of embryonic development are:
-Globular pro-embryo is formed.
-From the globular shape, the embryo develops into a heart-shaped form.
-The growing embryo then gets crowded which will make it bend.
-This embryo will then fill the seed.

Note: As double fertilization forms two products i.e., zygote and endosperm. This endosperm part provides nourishment to the developing embryo and thereby increasing the viability of seeds. In angiosperms, this fertilization process provides better chances of survival.