Q.During microsporogenesis, meiosis occurs in:

Microsporogenesis is the process by which microspore mother cells (also called pollen mother cells or PMCs) undergo meiosis to produce haploid microspores. These diploid microspore mother cells are located in the pollen sacs (microsporangia) of the anther.

The endothecium is a layer of the anther wall that helps in dehiscence but does not undergo meiosis. Microspore tetrads are the immediate product of meiosis—four haploid microspores held together temporarily—so meiosis has already occurred by this stage. Pollen grains develop later when individual microspores mature, well after meiosis is complete. …

To understand where meiosis happens during microsporogenesis, we need to first grasp what microsporogenesis actually is. This is the process by which pollen grains—the male gametophytes in flowering plants—are formed inside the anther. The anther is the pollen-producing part of the stamen, and its internal structure holds the key to understanding this process.

The anther contains four elongated pollen sacs arranged in two lobes. If you were to cut a transverse section through a young anther, you would see several distinct layers from the outside moving inward: the epidermis, endothecium, middle layers, and finally the tapetum, which is the innermost nutritive layer. At the very center of each pollen sac lies a group of compactly arranged homogeneous cells called the sporogenous tissue.

As the anther matures, each cell of this sporogenous tissue undergoes a transformation. These cells enlarge, become more conspicuous, and are now called microspore mother cells (MMCs) or pollen mother cells. Crucially, these MMCs are diploid cells—they contain the full complement of chromosomes characteristic of the sporophytic plant body.

Now comes the critical event: each microspore mother cell undergoes meiosis, a reductional division. This is the defining moment of microsporogenesis. Through meiosis, one diploid MMC divides to produce four haploid cells arranged in a cluster called a microspore tetrad. These four cells are the microspores, each containing half the chromosome number of the parent plant.