Abstract: Using paraffin section method and fluorescence microscopy , anther microstructure changes of pollenless abortion were observed in thermo- and photoperiod-sensitive genic male sterile line N28S in rice. The results showed that the microsporocytes of N28S had a reduced cytoplasm. Some microsporocytes didn′t undergo meiosis, the other microsporocytes arrested meiotic division at the leptotene stage of meiosis or underwent abnormal cytokinesis . All abnormal microsporocytes and meiotic products became vacuolate and eventually degenerated, leaving empty anther locules . Moreover, the absence or premature degradation of callose wall around the microsporocytes and the abnormal degradation of tapetum in the microspore
development stage were also been observed . It is suggested that the abnormal behaviour of callose and tapetum may be a consequence of a deviation in microsporocyte development, and the pollenless abortion of N28S is possibly attributed to microsporocytes with reduced cytoplasm .

Key words: Thermo- and photoperiod-sensitive genic male sterility