Abstract: Microsporogenesis and male gametophyte formation in Dolichos lablab L.were examined by using transmission electron-microscopy. It is the first time to be observed that the plastids and mitochondria have undergone two cycles of dedifferentiation and redifferentiation during the pro- cess of microsporogenesis and pollen development. In the first cycle the dedifferentiation of plastids and mitochondria occurs at prophase I of meiosis and the redifferentiation at telophase II. The second cycle is from dedifferentiation of plastids and mitochondria at late microspore stage to redifferentiation of plastids at early 2-celled pollen stage and of mitochondria at late 2-celled pollen. From the early microspore to the late 2-celled pollen stages, the golgi bodies are abundant.They are involved in the formation of both nexine and intine of pollen. The wall ingrowths of pri-mary intine of early 2-celled pollen enlarge the surface areas of the vegetative cell plasma mem-brane, and may facilitate the uptake of nutrients from the anther locule.

Key words: Dolichos lablab