不同地理区域间物种多样性差异在很大程度上是由于独特的气候历史及区域地理因素造成的。第四纪冰期气候变迁，使得多数物种分布区发生改变，从而进一步影响了物种的种群遗传结构。因此，对物种遗传变异分布模式（遗传结构）的研究可以追述现代植物分布种群的地理分布历史。中国南北有截然不同的气候类型，因此，分别生长南方地区和北方地区的植物在应对气候变迁有不同的响应模式，然而，以往的研究往往局限于分布在某一地区的单个物种。本项目拟用不同遗传背景的叶绿体DNA和核基因相结合的方法，研究分布在中国南北的近源物种广东地构叶和地构叶种群遗传变异的地理分布式样，并结合现代植物分子群体遗传学的分析方法，全面追述现代分布种群的进化历程，以及分布格局形成的历史原因和可能的冰期避难所；期望通过此研究，为中国植物物种响应过去气候变迁历史的生物地理学模式提供典型研究范例。

The different patterns of species diversity between regions result mainly from the differences in climate and geography (The species diversity are mainly influenced by historic, climatic and geographical factors). Climatic oscillations in the Quaternary have played a major role in changing the geographical distribution of plant and animal species and further affecting the genetic structure of populations. Thus, investigations into patterns of present-day genetic variation have provided an important alternative method for understanding the history of geographical distribution of species. The climate is distinctly different between South and north China. Therefore, the plants growing in the two areas could have evolved different adaptive responses to climate change. Different from the previous phylogeographic studies that have often focused on one species occurring in either south or north China, this project aims to use maternally inherited chloroplast DNA (cpDNA) and bi-parentally inherited nuclear DNA (nDNA) markers to assess and compare the extent and distribution of genetic variation within and between populations of Speranskia tuberculata Baill. And S. cantonensis (Hance) Pax et Hoffm, two closely related species distributed exclusively in north and south China, respectively. We will perform classic population genetics analyses to elucidate the distribution patterns of current populations and the historic reasons behind them, and make inferences about the possible glacial refugia. The resulting outcome of this research project would promise to provide new insights into how endemic plant species of China respond to past climate changes.