Question

During the formation of pollen grains, a microspore mother cell undergoes
(a) One meiotic division.
(b) One mitotic division.
(c) One meiotic and one mitotic division.
(d) One meiotic and two mitotic divisions.

Answer 1

During the formation of pollen grains, a microspore mother cell undergoes such division in which the number of chromosomes in the parent cell is reduced by half and produces four gamete cells.

Correct step by step answer:
Pollen grains are formed from the microspore mother cell when it undergoes one meiotic division by the process of microsporogenesis and microgametogenesis.
Microsporogenesis is the formation of haploid microspores from diploid microspore mother cells through meiosis when each produces four microspores. These microspores then undergo mitosis division to form pollen grains which at maturity consist of only three cells, the tube cell, and two non- motile sperm cells. So, microgametogenesis is the development of microspore into mature pollen grains. The pollen grains are the male gametes formed in the anther sac and are located along the inner edge of the anther sacs.
Hence, during the formation of pollen grains, the microspore mother cell undergoes one meiotic division to produce four haploid microspores, generally in the form of a tetrad, which then develops into pollen grains.
So, the correct answer is '(a) One meiotic division'.

Additional Information: Pollen grains are formed in the anther sac, by meiosis cell division when the microspore mother cell produces four microspores of pollen grains. Pollen grains are taken from the Greek word “play nos” which means dust or pollen containing the male gametophyte or microgametophyte phase of the plant.

Note: The pollen grains of seed-bearing plants are both remarkable and intensively studied structures that have evolved to ensure delivery of the male gametes to the embryo sac during sexual reproduction. Pollen, the haploid microgametophyte, is considered to be the male partner in sexual reproduction.