Question

Describe the development of the male gametophyte from the microspore mother cell to the production of sperm.

Answer 1

Hint: Pollen grains are developed from diploid microspore mother cells in pollen sacs of anther. The development of the male gametophyte occurs in both stamen and in the female reproductive part. The microspore mother cell is all the way converted into a sperm cell which is a final male gametophyte.

Complete step by step answer:
-The anther contains two lobes and each lobe has two pollen sacs or microsporangia. Each microsporangium has many microspore mother cells in it. The pollen sacs produce pollen grains.The pollen grain has two cells: large generative cell and one small tube cell. It is double layered sporoderm called outer exine and inner intine. The outer exine shows resistance to the environment which protects the pollen grain for fertilization.
-This pollen grain is transferred to the stigma of the flower. The secretion by the stigma to the pollen grain creates pressure and the intine comes out of the pollen grain and the pollen tube is initiated. The tube cell has stored food and energy.
-The tube cell, generative cell and cytoplasm all move to the pollen tube which is directed by the ovary’s chemical stimuli.
-This pollen tube consisting of two male gametes and a degenerating tube nucleus represents the male gametophyte.

Note:
The development of the pollen grain or male gametophyte is not limited to only pollen grain formation. The development of the male gametophyte requires the female reproductive parts like stigma and style.