AP BIOLOGY

Detailed explanation-1: -The pollen grain grows into the male gametophyte on germination which is initiated before pollination takes place. Inside the microsporangium, Pollen mother cell (PMC) undergoes meiosis and results in four microspores which eventually mature into pollen grains.

Detailed explanation-2: -So, the pollen is an immature or partially developed male gametophyte. Similarly, the unicellular microspore produces male gametes and develops into mature microgametophyte by the process of mitotic cell division. Hence, the pollen grains are immature male gametophyte and partially developed male gametophyte.

Detailed explanation-3: -The female gametophyte is also commonly called the embryo sac or megagametophyte. The male gametophyte, also called the pollen grain or microgametophyte, develops within the anther and consists of two sperm cells encased within a vegetative cell (Gifford and Foster, 1989).

Detailed explanation-4: -Male gametes are found inside tiny pollen grains on the anthers of flowers. Female gametes are found in the ovules of a flower. Pollination is the process that brings these male and female gametes together.

Detailed explanation-5: -Microspores and pollen grains are different forms of a male gametophyte. While microspores are small haploid spores formed after meiotic division, pollen grains are formed from the microspores after mitotic division.