Draw a labelled diagram of the sectional view of a mature pollen grain in angiosperms. Explain the functions of its different parts.

Explanation

Function of its Parts : Pollen grain develop inside the micro sporangia.
Exine The outer layer called the exine.
The exine exhibits a fascinating array of patterns and designs.
Intine The inner wall of the pollen grain is called the intine. When the Pollen grain is mature, it contains two cells.
(i) Vegetative cell (ii) Generative cells.
The Vegetative cell is bigger, has abundant food reserve and a irregularly shaped linoleus. The generative cell is small and floats in the cytoplasm of the vegitative cell.
In some angiosperms the generative cell divides mitotically to give rise to the two male gametes before the pollen grains are shed.