Yang Rui, Feng Xiuyan, Gong Xun
Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
Plant Divers. 2016 Dec 22;39(1):44-51. doi: 10.1016/j.pld.2016.11.003. eCollection 2017 Feb.
Geological activities and climate oscillations during the Quaternary period profoundly impacted the distribution of species in Southwest China. Some plant species may be harbored in refugia, such as the dry-hot valleys of Southwest China. X. Gong & W. Zhou, a critically endangered cycad species, which grows under the canopy in subtropical evergreen broad-leaved forests along the upstream drainage area of the Red River, is endemic to this refugium. In this study, 60 individuals of collected from six populations were analyzed by sequencing two chloroplast intergenic spacers (cpDNA: A-H and L-F) and two nuclear genes ( and ). Results showed high genetic diversity at the species level, but low within-population genetic diversity and high interpopulation genetic differentiation. A Bayesian phylogenetic tree based on cpDNA showed that five chloroplast haplotypes were clustered into two clades, which corresponds to the division of the western and eastern bank of the Red River. These data indicate a possible role for the Red River as a geographic barrier to gene flow in . Based on our findings, we propose appropriate and conservation strategies for .
第四纪时期的地质活动和气候振荡对中国西南地区的物种分布产生了深远影响。一些植物物种可能栖息在避难所中，比如中国西南的干热河谷。叉孢苏铁，一种极度濒危的苏铁物种，生长在红河上游流域亚热带常绿阔叶林的树冠层下，是这个避难所特有的物种。在本研究中，从六个种群采集的60个个体通过对两个叶绿体基因间隔区（叶绿体DNA：A-H和L-F）和两个核基因（和）进行测序来分析。结果表明，该物种在物种水平上具有较高的遗传多样性，但种群内遗传多样性较低，种群间遗传分化较高。基于叶绿体DNA构建的贝叶斯系统发育树表明，五个叶绿体单倍型聚为两个分支，这与红河东西岸的划分相对应。这些数据表明红河可能作为叉孢苏铁基因流动的地理屏障。基于我们的研究结果，我们提出了针对叉孢苏铁的适当迁地保护和就地保护策略。
