Microsporogenesis and Formation of the Male Gametophyte

Abstract

The life cycle of flowering plants is characterized by an alternation between a dominant sporophytic generation and a highly reduced gametophytic generation. The seedling plant born of germination of the seed and the adult plant evolved from the seedling, constituting parts of the sporophytic generation, were topics of discussion in the previous chapters. The sporophyte eventually produces flowers. As the name implies, the function of the sporophyte is to generate spores, and it does so by meiosis of the spore mother cells; spores germinate or divide by simple mitotic divisions to produce the gamete-producing generation called the gametophyte. Production of spores and formation of gametes are important events in the sexual reproductive cycle that take place in the flower. Flowering plants have two morphologically different kinds of gametophytes, one that gives rise to male gametes or sperm cells and another that produces female ga-metes or egg cells. The floral organ concerned with male sexual reproduction is the stamen, and the part of the stamen where events of male sexual reproduction occur is the anther. A number of morphological and cellular changes accompany the overall growth of the anther from its primordial stage to the point when sperm cells are produced.