Question

How many meiotic and mitotic divisions occur during the development of male gametophyte from the microspore mother cell?

• A. One meiotic and two mitotic
• B. Two meiotic only
• C. Two mitotic only
• D. One mitotic and one meiotic

Hint:

Meiosis in the MMC produces haploid microspores, while mitosis in the microspore forms the mature pollen grain with two sperm cells and a vegetative cell.

Answer 1

The Correct Option is A

The development of the male gametophyte in plants involves both meiotic and mitotic divisions beginning from the microspore mother cell. Let's break down the process step by step:

1. Initiation with the Microspore Mother Cell: The process begins with a diploid cell known as the microspore mother cell (also called the pollen mother cell).
2. Meiosis:
   • The microspore mother cell undergoes meiosis, a type of cell division that results in four haploid microspores. This is known as the tetrad stage.
   • Each microspore is haploid, meaning it contains a single set of chromosomes.
3. First Mitotic Division:
   • Each of these microspores undergoes a mitotic division to develop into a pollen grain consisting of a vegetative cell and a generative cell.
   • At this stage, the pollen grain is still immature.
4. Second Mitotic Division:
   • The generative cell, within the pollen grain, undergoes a further mitotic division to produce two sperm cells.
   • This division completes the development of the mature male gametophyte, which is ready for fertilization after pollination.

Therefore, during the development of the male gametophyte from the microspore mother cell, there is one meiotic division to produce four microspores, followed by two mitotic divisions (one to form the generative cell and another within the generative cell to form two sperm cells).

Conclusion: The correct answer is "One meiotic and two mitotic" divisions occur during the development of male gametophyte from the microspore mother cell.