Abstract:Cytological observations of microsporogenesis and pollen development in vivo in wheat were carried on by means of phase contrast optics, which could avoid the distortions resulted from materials difficult to be fixed. The cytological changes were observed as follows: 1. Just before first mitosis of pollen, many strands of cytoplasm arose from one side of the nucleus facing the aperture, and moved swingingly toward the aperture. And then these strands of cytoplasm combined into one mass and protruded in the large vacuole. 2. There was a alteration in the direction of the spindle axis from obliquity to parallelism in anaphase. 3. Forming course of the wall between generative and vegetative cell. 4. Dynamic course of the disintegration of wall between vegetative and generative cell as well as that the generative cell came into the vetetafive cell.