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运用压片法对秋水仙素滴注处理后的‘无核丰’枣小孢子母细胞减数分裂行为及其与花蕾外部形态变化的相关性进行了研究,并测定了2n花粉的比例。结果表明:秋水仙素处理后枣小孢子母细胞第一次减数分裂正常;在减数分裂前期Ⅱ观察到胞质分裂异常现象;中期Ⅱ纺锤体主要有4种类型:平行型、垂直型、八字型和融合型,分别占27.31%、19.35%、45.27%和8.06%;四分体时期观察到二分体、三分体、四分体,分别占6.00%、43.04%、50.96%;定位异常纺锤体八字型与融合型分别与三分体、二分体呈正相关;秋水仙素处理后‘无核丰’枣2n花粉的形成受胞质分裂异常、纺锤体定位异常两种机制控制,因纺锤体定位异常而产生的2n花粉占2n花粉总数的96.97%,遗传上等同于FDR(第1次分裂重组)型配子,因胞质分裂异常产生的2n花粉在遗传上等同于SDR(第2次分裂重组)型配子;秋水仙素处理后‘无核丰’枣2n花粉绝大多数为FDR型,因而在枣有性多倍化中具有重要的利用价值。小孢子母细胞减数分裂进程与花蕾外部形态变化具有对应关系,花蕾直径达到1.34 mm时,小孢子母细胞开始进入减数分裂;达到1.68 mm时,小孢子母细胞进入四分体时期;超过1.92 mm时,减数分裂结束,且有大量花粉粒形成。2n花粉诱导最佳的秋水仙素滴注时期为细线期末期,即花蕾直径在1.34~1.42 mm时,诱导后‘无核丰’枣2n花粉发生比例为17.36%。
The meiosis behavior of microspore mother cells and their correlation with external morphological changes of ’Budless’ jujube were studied by using tabletting method and the proportion of 2n pollen was determined. The results showed that the first meiosis of juvenile microsporocytes was normal after treatment with colchicine, abnormal cytokinesis was observed in pre-meiotic stage Ⅱ, and there were mainly four types of mid-spindle Ⅱ spindle: parallel and vertical , Zigzag type and fusion type respectively, accounting for 27.31%, 19.35%, 45.27% and 8.06% respectively. In the tetrad, dives, trispersons and tetrad were observed, accounting for 6.00%, 43.04% and 50.96% respectively. The abnormalities of spindle orientation and fusion were positively correlated with trisomies and dichotomies, respectively. The formation of 2n pollen of ’Nongfengfeng’ jujube 2n after colchicine treatment was controlled by the two mechanisms of abnormal cytoplasmic division and spindle orientation , 2n pollen due to abnormal spindle orientation accounted for 96.97% of the total number of 2n pollen, genetically identical to FDR (1st division recombination) type gametes, 2n pollen due to abnormal cytokinesis is genetically equivalent to SDR ( The second split-recombination) type gametophyte; colchicine treatment ’non-nuclear-rich’ jujube 2n pollen most of the FDR type, and therefore have a date in the polyploidization of the value. The meiosis process of microspore mother cells was related to the change of bud morphology. When the bud diameter reached 1.34 mm, the microspore mother cells began to enter meiosis. When the number of microspore mother cells reached 1.68 mm, the microspore mother cells entered the quartile. At 1.92 mm, meiosis was over and a large amount of pollen grains formed. The best colchicines in 2n pollen induction period was the end of the fine line, that is, the flower bud diameter was 1.34-1.42 mm, and the proportion of ’non-nuclear abundance’ jujube 2n pollen was 17.36%.