Question

When a pollen grain falls on the stigma of the pistil, the pollen grain grows a ______ downwards through the style towards the female gametes in the ovary.

Answer 1

Pollination:
The transfer of the pollen grains from the male part of the plant (anther of a stamen) to the female part of the plant (stigma of a pistil) is called pollination.

Pollen tube:

1. When a pollen grain lands on the stigma, it develops a pollen tube to reach the ovary.
2. The pollen tube fuses with the female sex cell that is the ovule.
3. It releases two male gametes before fusing with the ovule to form a seed.

Final answer: When a pollen grain falls on the stigma of the pistil, the pollen grain grows a pollen tube downwards through the style towards the female gametes in the ovary.