同一居群韭莲不同植株减数分裂行为差异的遗传分析

Genetic analysis of meiotic behavior difference in plants from the same population of Zephyranthes grandiflora

关键词:  韭莲  减数分裂  小孢子发育  多极分离  臂内倒位  纺锤体变异

Key words:  Zephyranthes grandiflora  meiotic behaviour  microspore development  multi-polar separations  paracentric inversion  spindle mutation

摘要:

对韭莲(2n=48)小孢子母细胞减数分裂及小孢子发育进行研究。结果显示同一居群植株的减数分裂行为存在明显差异。多数韭莲植株小孢子母细胞减数分裂存在少量落后染色体、微核等现象,平均每株中具有异常分离行为的母细胞占14.02%,小孢子发育正常,但花粉无活力。并首次从减数分裂后期Ⅰ的特殊的细胞学形态证明韭莲是臂内倒位杂合体。而少数植株韭莲的小孢子母细胞减数分裂极其紊乱,后期Ⅰ出现多极分离、大量落后染色体,小孢子母细胞减数分裂总异常分离高达94.3%。四分孢子期多分孢子体高达73.4%。分析认为:前者减数分裂行为异常的原因主要由染色体结构变异所致,而后者的原因除染色体结构变异外,还可能与控制纺锤体形成的基因突变有关。

Abstract:

In this paper,the meiotic behavior of microsporocytes and microspore development in Zephyranthes grandiflora(2n=48)were investigated.The results indicated that there was obvious difference of meiotic behavior in Z.grandiflora plants from the same population.In most plants,lagging chromosome,micronucleolus and other abnormal meiotic behavior could be observed,with an average of 14.02% microsporocytes segregating abnormally. Microspores developed normally,but no fertile pollens could be obtained. Form the abnormal meiotic behavior of microsporocyte in anaphase Ⅰ,it could be proved that the Z.grandiflora was a heterozygote of paracentric inversion for the first time. The meiosis of microsporocyte of a few mutant plants showed disorderly greatly,and multi-polar separation and lagging chromosomes could be readily in anaphase Ⅰ,with and average of up to 94.3% abnormal segregating ate.At tetraspore stage,paraspores raised up to 73.4%.It is thought that abnormality of meiosis in Z.grandiflora was ascribed mainly to chromosome structure variation,and the reason of the behavior abnormality of the meiosis in mutant plants was due to gene mutation that controling the spindle formation,in addition to chromosome structure variation.