泛热带植物区系的生物地理起源与演化——以豆科羊蹄甲属为例

泛热带植物区系长期以来为植物学家和生物地理学家所关注。学者们分别提出了基于隔离分化思想和迁移扩散思想的一些假说来解释其起源和分布格局的形成。这些假说的提出主要基于化石记录和对各大陆区系成分的统计和分析；对具体的泛热带植物类群进行分子生物地理学研究才刚刚起步。本项目拟首次对一个典型的泛热带分布的被子植物大属- - 豆科羊蹄甲属进行分子生物地理学研究。在本项目中，我们拟通过野外采集和从馆藏标本获取分子材料，使用5个DNA片段对全球范围内的羊蹄甲属内所有组和85-95%的物种进行分析，构建较完整的羊蹄甲属分子系统发育。在此基础上，结合羊蹄甲属以及外类群的化石记录和各物种的地理分布，探讨羊蹄甲属的起源时间、起源地点和属内不同谱系在各大陆间的生物地理演化历史。该研究可望为探讨泛热带植物区系的起源和演化提供一个较领先的案例。

The flora of the pantropics has long attracted botanists and biogeographers. Hypotheses based on either vicariance or dispersal have been developed to explain its origin and biogeographic diversification. Evidence supporting these hypotheses was mainly from fossil records and floristic comparison of discontinous continents. Recently, molecular biogeographic analyses have been carried out on a few plant taxa, either at species level in small genera or at higher level in families or orders. We firstly propose here to use molecular data to analyze the origin and biogeographic diversification of Bauhinia,a species-rich genus of angiosperm in the pantropics. Molecular materials covering all sections and 85-95% species of the genus will be collected from herbariums or by field works. Using five DNA markers (ETS, ITS, rpl32-trnK spacer, trnL-trnK spacer and rps16 intron), we aim to reconstruct a deeply-sampled and well-resolved phylogeny of Bauhinia. Based on the phylogenetic framework of the genus, we will futher combine data of fossil records and species distributions to construct the origin and biogeographic diversification of the genus. The proposed project will hopefully provide a new and detailed case in extending the frontiers of our knownledge on origin and biogeographic diversification of the pantropic flora.