中文摘要：

利用透射电子显微镜对同源四倍体水稻小孢子母细胞减数分裂前及期间的超微结构进行观察,结果发现：（1）减数分裂前及减数分裂早期,小孢子母细胞核糖体密度高,线粒体、质体等细胞器丰富;粗线期核糖体密度显著下降,线粒体、质体等细胞器数量减少;终变期核糖体密度逐渐恢复到减数分裂前状态,而其他细胞器的数量除在二分体时期出现短暂的回升,终变期以后的时期均较少。（2）小孢子母细胞间的连接在小孢子母细胞时期以典型的胞间连丝为主,进入细线期,胞间连丝数量显著减少,宽孔道的胞质通道逐渐增多,粗线期小孢子母细胞间基本通过胞质通道连接,终变期小孢子母细胞间完全分离。（3）随着减数分裂的进行,药壁四层细胞逐渐液泡化,绒毡层细胞中部分小液泡融合成大液泡,形成胞内＂空腔＂;药室内壁细胞出现大量的具有叶绿体结构特征的质体,内含丰富的淀粉粒,到了四分体时期质体数量及内含的淀粉粒显著减少。

英文摘要：

By using technology of transmission electron microscope,we observed ultrastructure in pre-meiotic and meiotic process of microsporocyte in autotetraploid rice.The results indicated：before and during early meiosis,microsporocytes contained high density of ribosome and numerous organelles such as mitochondrias,plastids and so on.The density of ribosome and the number of organelles decreased significantly at pachytene stage.At diakinesis stage,density of ribosome went back gradually to the same level as at stage of pre-meiosis,but density of other organelles decreased at all stages after diakinesis except for a transient increase at dyad stage.The intercellular connection between microsporocytes was mainly typical plasmodesma at the microsporocyte stage.After entering the leptotene stage,the plasmodesmas diminished markedly,and the cytoplasmic channel with wider channel increased gradually and became the main connection between microsporocytes at pachytene stage and diakinesis stage before the microsporocytes separated completely.During the process of meiosis,cells of anther wall became vacuolization by degrees,and some part of small vacuoles in tapetal cells finally fused into big vacuoles forming ＂cavity＂ of cell.Numerous plastids with chloroplast structural characteristics and abundant starch-grains presented in the endothecium cells,and the number of plastids and starch-grains decreased strikingly after entering tetrad stage.