Abstract:

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.

Key words: Chinese white poplar, Pollen abortion, Cytogenetic, Mechanism