Question

Explain the events up to double fertilization after the pollen tube enters one of the synergids in an ovule of an angiosperm.

Answer 1

Dear Student

In plants, pollination is followed by fertilization. Once the pollen grains are deposited on the stigma, they form tubes called pollen tubes. The pollen tubes grow through the style and reach the ovary where ovules are located. The pollen tube normally enters the ovule through a small opening called micropyle. Inside the ovule, the pollen tube releases two male gametes into the embryo sac via one of the synergids. The embryo sac of the ovule contains the egg.

Double fertilization is a characteristic feature of flowering plants. In the process of double fertilization out of the two sperm nucleus, one sperm nucleus fuses with the egg nucleus to form a diploid embryo ( process is called syngamy) and another fuses with polar nuclei to form a triploid endosperm ( process is called triple fusion). Since two kinds of fusion—syngamy and triple fusion—take place, the process is known as double fertilisation.

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