[The ultrastructural observation of anthers of Chinese cabbage's mail-sterility]

The fertile and sterile anthers of a Chinese cabbage (Brassica campestris L. ssp. chinensis Makino) were observed using electron microscope to find the ultrastructural feature of sterile anthers. The earliest abnormal phenomenon in sterile anther was nucleolus of sporogenous cells locating in the edge of nucleus. During microspore mother cell development, callus wall surrounding the cell displayed uneven in the thick ness and was discontinuous,and the some cytoplasm leaked out of the cell from some rifts in the wall. After meiosis of microspore mother cells, the cells of tetrad were irregular and some of them contained several nuclei. The exine of pollen began to be formed in tetrad in this cabbage. The evident disorder during exine formation in the sterile pollen occurred during its primexine formation and then the sporopollenin was irregularly deposited to form a layer of uneven and discontinuous pollen exine. Cytoplasm of aborting microspores contracted and finally degenerated after them released from tetrad. The tapetal cells of fertile anther began to synthesis abundant lipid material during microspore development. However, the tapetal cells of sterile anther did not synthesis lipid material during microspore aborting. The microspore abortion was first and tapetal degeneration second. Therefore, aborting microspore induced the functional default of tapetal cells synthesizing lipid material. The ultrastructural results on this study further complete and correct our previous results obtained by light microscope.