Abstract:Using techniques of intact microspore, semi-thin section and ultra-thin section, the cytological differences in microspores and anther cell walls between pollen sterile hybrid F1 and its fertile parent Taichung 65 (Oryza sativa L.) were studied. When hybrid F1 microspores developed to the uninucleate middle and late stage, cytoplasm-condensed microspores had much more than those in Taichung 65, and star-like microspores appeared, but normal microspores and starch accumulated microspores decreased. when anthers of hybrid F1 were cultured in vitro, the development of cytoplasm-condensed microspores, star-like microspores, normal microspores, vacuole microspores and starch accumulated microspores would follow the microspore cytoplasm condensed process, sporophytic developmental process, gametophytic developmental process, vacuole process and starch accumulated process, respectively. Compared to Taichung 65, the degradation of tapetum layer in anther cell wall of hybrid F1 grew quickly and middle layer cell expanded larger under culrued in vitro. These differences in microspore and anther wall between hybrid F1 and Taichung 65 were probably caused by the interaction of alleles in pollen sterility locus S-a and culture environment in vitro.