(b) Each cell of sporogenous tissue, gives rise to microspore mother cell. The process of formation of microspores from a pollen mother cell (PMC) through meiosis is called microsporogenesis. The microsopores as they are formed are arranged in a cluster of four cells, i.e., the microspore tetrad. At the 2-celled stage, the microspores dissociate form pollen grains (male gametophyte).