温敏雄性不育系小麦BNS败育的细胞学观察

目的]为了明确温敏雄性不育系小麦BNS雄性败育的细胞学机制.方法]采用醋酸洋红染色对温敏雄性不育系小麦BNS花粉母细胞减数分裂和小孢子发育过程进行细胞学观察,采用浓度1％I2-KI溶液染色法进行花粉育性统计.结果]BNS不育系在减数分裂过程中异常,中期Ⅰ出现染色体滞后现象;二分体时期细胞质分配不均匀,染色体靠边,没有在细胞中央;四分体时期子细胞大小不一,其子细胞存在落后染色体,有的二分体经过第2次分裂没有形成4个子细胞,而是分成3个子细胞;小孢子发育过程中观察到单核靠边期,未能发育到双核期和三核期,还出现空孢现象;开花期的花粉彻底败育.而扬麦13能形成正常的二核期和三核期,花粉可育.结论]减数分裂过程中出现的异常行为是导致BNS花粉败育的原因之一.单核期是其败育的关键时期.

Cytological Observations of Male Abortion of Thermo-sensitive Male Sterile Wheat BNS

Objectivei The research aimect ＂to clarify the cytological mechanism of the＂ male abortion of thermo-sensitive male sterile wheat BNS. Method] This test used acetic acid magenta staining to conduct cytological observation on pollen mother cell meiosis and the microspore development of BNS process, and 1% I2-KI solution staining to measure the pollen fertility. Result] The mother cells of the male-sterile line BNS were abnormal during meiosis, such as laggard chromosomes phenomenon appeared at metaphase I, and non-uniform cytoplasm distribu- ted or the chromosome aside in the cell at dyad. During tetrad daughter cells showed different size and laggard chromosomes. Some dyads didn form four daughter cells but three cells after second division. The microspore could develop to late-mononuclear stage, but failed to binuclear and trinucleate stage, and the empty spore phenomenon appeared as well. The pollen in the male-sterile line was thoroughly abortive at flower- ing stage, while that in Yangmai 13 was fertile because it could form binuclear and trinucleate. Conclusion]Abnormal meiosis is one cause of pollen abortion of BNS, and mononuclear period is the critical period of abortion.