(a) Explain the process of the development of a male gametophyte in an angiosperm. (b) Why is it called a male gametophyte ?

Correct Answer:
(a) Cells of the sporogenous tissue (Microspore mother cell or Pollen Mother Cell/PMC) in the anther undergo meiotic division to form a microspore tetrad, which matures and dissociates to form pollen grains (the male gametophyte).
(b) It is called a male gametophyte because its generative cell divides to form two male gametes.

Step-by-Step Explanation:

Part (a): Development of the Male Gametophyte (Microsporogenesis)
1. Precursor Cells: Inside the young anther of a flower, there is a central mass of diploid cells called the sporogenous tissue. Each cell of this tissue is capable of giving rise to microspores and is known as a Microspore Mother Cell (MMC) or Pollen Mother Cell (PMC).
2. Meiotic Division (Meiosis): Each diploid ( $2n$ ) pollen mother cell undergoes meiosis (reduction division) to produce four haploid ( $n$ ) microspores. These four microspores are initially clustered together in a group called a microspore tetrad.
3. Dissociation and Maturation: As the anther matures and dehydrates, the individual microspores within the tetrad dissociate (separate) from one another. They undergo further development, forming a tough outer wall (exine) and inner wall (intine) to become mature pollen grains, which represent the male gametophyte.

Part (b): Why it is called a Male Gametophyte
1. Cellular Structure: A mature pollen grain typically contains two cells: a larger vegetative cell and a smaller generative cell.
2. Gamete Production: It is designated as the male gametophyte because the generative cell undergoes mitotic division to produce two male gametes (sperm cells). In plant biology, the suffix "-phyte" refers to the plant body, and "gametophyte" literally translates to the "gamete-producing plant body." Since the pollen grain houses and produces the male gametes, it is the male gametophyte.