Question

Explain the post-pollination events leading to seed production in angiosperms.

Answer 1

Pollination is the process of transfer of pollen grains from anther to stigma.

• When the pollen grains fall on the stigma, the pollen tube enters one of the synergids and releases two male gametes.

• One of the male gametes moves towards the egg cell and fuses with it to form zygote.

• The other male gamete fuses with the two polar nuclei and forms the primary endosperm nucleus. This is termed as triple fusion.

• After the triple fusion, the central cell becomes the primary endosperm cell (PEC).

• The primary endosperm nucleus gives rise to endosperm, while the zygote develops into embryo.

• Seeds are the fertilised ovules that are developed inside a fruit.​
• The integuments of ovules harden to form the seed coat, and the micropyle facilitates the entry of oxygen and water into the seed.