毛乌素沙地中国沙棘无性系种群年龄结构动态与遗传后果研究

根据样地每木栓尺和林缘扩散效应调查以及无性系跟踪挖掘材料,分析了毛乌素沙地中国沙棘无性系各上群年龄结构动态及其遗传后果,结果表明,中国沙棘无性系种群年龄结构由增长型经过稳定型发展到衰退型,在衰退的种群中,中国沙棘能够通过无性系生长实验林窗更新恢复其稳定性或依靠林缘扩散使种群在更大的空间尺度上进行自我维持。同时,随着种群的自疏,无性系种群的组成由较多拥有较少分株的无性系向较少拥有较多分株的无性系转变,从而降低了无性系种群的基株多样性。

Age-structure dynamics and genetic consequences of Hippophea rhamnoides L. subsp sinensis clone population in Mu Su sandland

Based on the measurement of all individuals of population at different successional stage,the investigation on edge dispersal effect and the following excavation of clones,the dynamics of age structure and genetic consequences of Hippophea rhamnoides L.subsp sinensis clone population in Mu Su sandland were examined. The results showed that the age structure of the clone population was characterized by a transformation from an increasing type in the early period starting from the initial colonization through a stable type to a declining type. The clone population could maintain or recover its stability by edge dispersal and gap regeneration with clonal growth. As the population self thinned, the composition of clone population changed from more clones with less ramets to less clones with more ramets and the genetic diversity of clone population decreased.