Abstract: Using traditional paraffin wax section, fluorescence microscopy, cytochemistry and TEM techniques, the microsporogenesis and male gametophyte development of Cynanchum otophyllum Schneid were observed in detail. The results showed that the anthers are 2-locular; the archesporium is hypodermal in origin and differentiates at two places; the archesporial cells divide periclinally to form a primary parietal layer and the primary sporogenous layer; the parietal layer then divides to form the tapetum; the tapetum is formed by 1-2 layers cells and is of the secretory type, it provides food materials to the developing microspores and the secretion to form the membrane of pollinium; the primary sporogenous cells function directly as the microspore mother cells; there are some starch grains, protein, endoplasm, chloroplast, lipocyte and vacuole existed in mature pollens; the membrane of pollen and pollinium contains protein and lipid; the nucleus of the microspore divides to produce the vegetative and generative nuclei; no true cell plate is formed but the cells are separated by a clear concave space; the generative cell is lenticular in outline and smaller in size than the vegetative cell.

Key words: Cynanchum otophyllum Schneid, microsporogenesis, male gametophyte