白菜核雄性不育花药超微结构的研究

对白菜核雄性不育两用系的可育与不育花药进行了超微结构的比较观察。结果显示不育花药的造孢细胞核仁靠边分布；包裹小孢子母细胞的胼胝质厚薄不均匀，不完整等早期异常现象。减数分裂后．四分体细胞中常有多个细胞核。从四分体释放出的小孢子外壁的孢粉素物质不均匀沉积，呈不连续的单层异常结构。最后小孢子通过细胞质收缩方式败育。在可育花药中．绒毡层细胞在小孢子发育后期已显示出退化迹象，同时在细胞中开始积累脂类物质。但在同时期的不育花药中．绒毡层细胞没有显示出退化的迹象，也不合成脂类物质。从时间上看，败育花药中小孢子母细胞及小孢子的异常在先，绒毡层细胞的异常在后。本研究揭示了白菜核雄性不育花药的超微结构特征．对我们以前的光学显微镜观察结果予以补充和修正。

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.