毛白杨花粉败育机制的研究

摘要

从细胞遗传学角度较为系统地揭示了毛白杨花粉败育的机制，即主要是毛白杨异质性遗传基础与环境相互作用的结果。(1)在减数分裂中有数目不等的联合程度较差的单价体以及落后染色体出现，这种与异质性相关的染色体行为异常，导致同源染色体向子细胞的不均衡分配，造成具功能染色体的缺失，从而引起毛白杨一定比率的败育花粉的产生；(2)遗传上的不平衡与温度等环境因子相互作用，进一步引发毛白杨生理乃至结构上的不平衡，花粉母细胞(或孢原细胞)和绒毡层细胞发育异常，从而造成不产粉或产粉较少；环境与基因型互作的差异性导致了花粉败育的年度不稳定性。(3)易位、倒位等染色体结构变异和天然三倍体株系的存在也是造成毛白杨花粉败育的原因。%The mechanism of pollen abortion in Chinese white poplar was revealed systematically from the observation of cytogenetics in this paper,that is,principally,resulted from interactions between environment and genetic heterogenetic basis of the species.(1)Unequal number of univalents with decreased degree of synapsis and lagging chromosomes occurred in meiosis.The abnormal chromosomal behavior correlated with heterogenicity gave rise to unequal allocation of homogenous chromosomes to daughter cells and resulted in the deletion of functional chromosoms,thus led to the occurence of a certion proportion of aborted pollens.(2)The interaction between genetic imbalance and such environmental factors as temperature,etc.,further drew forth physiological and even structrural imbalance,with abnormal development of pollen mother cells (orsporogonium) and tapetal cells,and consequently resulted in no or very few production of pollens.The difference in the interaction between environment and genotype reflected on the unstability of pollen abortion in different years.(3)The esistence of chromosome structrural variations,such as inversion,translocation,etc.And natural triploid may also cause the occurrence of pollen abortion.