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本文阐明了烟草单培体花粉植株小孢子母细胞的减数分裂和小孢子发育的过程。发现由于前期Ⅰ时没有同源染色体配对,中期Ⅰ时染色体分散于细胞质中,绝大多数细胞的染色体不排列于赤道板上,仅少数细胞有赤道板的形成。后期Ⅰ时单价染色体随机分布两极,故末期Ⅰ形成大小不等的双核或多核。减数分裂Ⅱ为两条染色单体分离,表现基本正常,形成含有两两相等染色体数目的四核或多核。减数分裂还发现了异常的连续型分裂和四分孢子呈平面体型。小孢子较小,平均直径为16μ,与二倍体烟草的小孢子相比,经测定其差异达到极显著水平。小孢子的细胞质退化,未发现有丝分裂,基本上形成不育的小孢子。
In this paper, the process of meiosis and microspore development of microspore mother cells in tobacco monoculture pollen plants was described. It was found that there was no homologous chromosome pairing in the early stage Ⅰ. The metaphase Ⅰ chromosome was dispersed in the cytoplasm. The chromosomes of most cells were not arranged on the equatorial plate, but only a few cells had the formation of the equatorial plate. The late monochromatic chromosome I randomly distributed bipolar, so the end of the formation of Ⅰ unequal size of the dual-core or multi-core. Meiosis Ⅱ separated for the two chromatids, the performance of the basic normal, the formation of chromosomes containing two or two equal number of quadruplets or polynuclear. Meiosis also found abnormal continuous division and tetradospores in a flat body shape. Microspores were smaller with an average diameter of 16μ, which was significantly different from that of diploid tobacco microspores. Microspore cytoplasm degeneration, did not find mitosis, basically forming sterile microspores.