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

摘要： 用透射电镜对扁豆 Dolichos lablab L．的小孢子发生和雄配子体形成过程进行了观察。首次观察到扁豆花粉发育过程中，其质体与线粒体去分化、再分化发生于整个花粉发育过程中，并经历了两个去分化和再分化的周期。第1个周期去分化发生在减数分裂前期I，再分化发生于减数分裂末期Ⅱ。第2个周期是在小孢子晚期的去分化和二胞花粉早期（质体）及二胞花粉晚期（线粒体）的再分化。高尔基体从游离小孢子早期到二胞花粉晚期均较丰富，并参与外壁内层及内壁的形成。二胞花粉早期的初始内壁形成了壁内突，扩大了营养细胞质膜的表面积，增强了花粉从药室内吸收养料的功能。

关键词: 扁豆, 花粉发育, 超微结构, 质体与线粒体的去分化和再分化