Question

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

Answer 1

The events which occur during double fertilization are:

Two male gametes are released by the pollen tube into the cytoplasm of synergid.

One of these male gametes moves towards the egg cell and fuses with the nucleus. This process is called syngamy and results in the formation of a diploid cell, zygote, which eventually forms an embryo.

The other male gamete moves towards the polar nuclei located in the central cell and fuses with them to form a triploid primary endosperm nucleus (PEN). This process is called triple fusion.

Since two types of fusion, syngamy and triple fusion, take place here, the phenomenon is called double fertilisation.