水稻雄性不育系珍汕97A小孢子发育过程中的微管骨架

摘要

水稻(Oryza sativa L.)雄性不育系珍汕97A、保持系珍汕97B和恢复系测64三系小孢子发生过程的研究表明:恢复系测64小孢子母细胞细胞质浓,有明显的微管荧光围绕着细胞核.小孢子母细胞经两次减数分裂形成四分体.四分体和小孢子的微管从细胞核表面向胞质周缘延伸,形成放射性排列格局,花粉发育正常.细胞质中有少量点状微管荧光.保持系珍汕97B小孢子发生过程的细胞形态和微管结构与恢复系测64相似,但细胞质中的点状微管荧光多一些.雄性不育系珍汕97A小孢子发生早期,小孢子母细胞内出现液泡,核中染色质凝集,微管荧光很弱,没有清晰的微管丝结构,细胞质中有许多点状微管荧光等不正常现象.小孢子母细胞经过减数分裂形成的四分体也没有清晰的丝状微管结构.随后,所有的小孢子迅速败育.雄性不育系珍汕97A在小孢子母细胞发生的很早时期,微管结构就明显不正常.%Histological changes that occur during microsporogenesis are documented in a gene-cytoplasmic male sterile rice (Oryza sativa L.) line, Zhen Shan 97A, its maintainer line, Zhen Shan 97B, and the restorer line, Ce64 of a 3-line hybrid rice production system. In the restorer line, Ce64, the developing microsporocytes have dense cytoplasm and a distinct set of circumferential microtubules around the nucleus. Successive cytokinesis results in the formation of tetrads. The microtubules within the cells of tetrads and microspores radiate from the surface of the nucleus towards the outer edge of the cytoplasm. Subsequent pollen development is normal. During the course of microspore formation tubulin speckles can be found in the cytoplasm. The general pattern of development and microtubule organization in the maintainer line, Zhen Shan 97B, is similar to Ce64, except that a few more tubulin speckles appear during microspore formation. In the case of the male sterile line, Zhen Shan 97A, a number of abnormalities can be discerned during early microsporogenesis. These include vacuoles forming within the developing microsporocyte and faintly stained microtubules with no defined distribution pattern. Prominent tubulin speckles are common within the cytoplasm. For those microsporocytes that undergo meiosis, no defined organizational patterns of microtubules can be found within the tetrad. All microspores abort soon after. Abnormalities and defects in microtubule organization observed in Zhen Shan 97A showed that complex interactions between the cytoplasm and the nucleus began at very early stage of microsporocyte development.