Question

Describe the process of double fertilisation in plants.

Answer 1

Double fertilization event is unique to Angiosperms (Flowering plants). After pollen is deposited on the stigma, it must germinate and grow through the style to reach the ovule. The microspores, or the pollen, contain two cells: the pollen tube cell and the generative cell. The pollen tube cell grows into a pollen tube through which the generative cell travels.

The germination of the pollen tube requires water, oxygen, and certain chemical signals. As it travels through the style to reach the embryo sac, the pollen tube's growth is supported by the tissues of the style. During this process, if the generative cell has not already split into two cells, it now divides to form two sperm cells. The pollen tube is guided by the chemicals secreted by the synergids present in the embryo sac; it enters the ovule sac through the micropyle. Of the two sperm cells, one sperm fertilizes the egg cell, forming a diploid zygote (having 2 sets of chromosomes); the other sperm fuses with the two polar nuclei, forming a triploid cell (Having 3 sets of chromosomes) that develops into the endosperm. Together, these two fertilization events in angiosperms are known as double fertilization .

source:-quora.com

Answer 2

Double fertilisation is a complex fertilisation mechanism of flowering plants.
This process involves the joining of a female gamete with two male gamete. Of the two sperm cells, one sperm fertilises the egg cell forming a diploid zygote. The other sperm fuses with the two polar nuclei forming a triploid cell that develops into the endosperm. Together these two fertilisation events which occurs in plants are called double fertilisation in plants.


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