Question

How does the pollen mother cell develop into a mature pollen grain? Illustrate the stages with labelled diagrams.

Answer 1

Development of Pollen Grain

1. In the developing anther, the microspore mother cells are present inside the pollen sacs.
2. Each microspore mother cell is diploid (2n).
3. It undergoes Meiosis I and Meiosis II to form a tetrad of four haploid microspores.
4. The four microspores separate from the tetrad and become free haploid microspores.
5. Each microspore develops into a mature pollen grain.
6. The mature pollen grain has two wall layers:
   • Exine – outer thick wall
   • Intine – inner thin wall
7. Inside the pollen grain, the nucleus divides to form:
   • Vegetative nucleus
   • Generative nucleus
8. After maturation, the anther dehisces and releases the mature pollen grains.