中文摘要：

以PCR产物克隆后测序的方法测定了贵州赤水桫椤国家级自然保护区3个种群59个个体的叶绿体DNA（cpDNA）atpB—rbcL非编码区序列。序列长度介于727～732bp之间，具长度多态性，A＋T百分比含量较高，介于63．27％～63．89％之间。遗传多样性水平较低，表现出较高的单倍型多样（h=0．639）和低的核苷酸多样性（Dij=0．00028）并存的特征，提示现有种群可能源自一个有效群体规模较小的种群的快速扩张，扩张时间尚短，不足以形成更为复杂的遗传结构。种群间的高基因流Nm、低遗传分化度峙、AMOVA分析以及DNA歧异度结果一致显示各种群间无明显的遗传分化。

英文摘要：

Chloroplast DNA （cpDNA） atpB-rbcL noncoding sequence of Alsophila spodophylla, collected from three populations distributed at Asphole National Nature Reserve in Chishui of Guizhou province were sequenced. Sequence length varied from 726-732 bp, showing length polymorphism, with high A＋T content between 63.27% and 63.89%. High level ofhaplotype diversity （h=0.639） and a low nucleotide diversity （Dij=0.000 28） were detected in the populations of A lsophila spinulosa. This suggested rapid demographic expansion from a small effective population, and, since then, there has been insufficient time to form a more complicated population structure. Observed high gene flow Nm, low FST, AMOVA analysis and DNA divergence data consistently indicated that no genetic differentiation should occur at the population level.