热带亚洲与热带美洲植物间断分布成因研究—以豆科红豆属为例

热带亚洲与热带美洲植物间断分布是最古老和最复杂的地理分布格局之一，其形成机制与演化历史对植物区系地理学、历史生物地理学等基础领域的研究至关重要，却长期被相关学界所忽视。该区域复杂的古环境历史导致了间断植物类群的起源与演化模式不尽相同，有必要对其进行范例研究。豆科红豆属约130种，是热带亚洲-热带美洲植物间断分布型的代表类群之一，其属内系统发育关系与时空演化历史尚不明了。本项目拟采用改良版Hyb-Seq高通量测序法获取大量低拷贝核基因与叶绿体基因组，重建红豆属的属内系统发育框架；以此为基础，结合分子钟法与可靠的化石记录，推测该属的起源、分化时间与祖先分布区；并整合分子证据与生态位建模分析，探讨红豆属内一珍稀濒危物种—花榈木—的谱系地理学问题，作为对属级生物地理学研究的补充与加强。本项目以红豆属为例，探讨热带亚洲与热带美洲植物间断分布的成因，并为跨太平洋热带、亚热带植物区系的演化研究提供参考。

Tropical Asian-tropical American disjunction is one of the oldest and the most complex distributional patterns in plants, of which formation and evolutionary history are vital to the fundamental studies on floristics, historical biogeography, etc. But such pattern was less concerned by phytogeographers. The complicated paleoenvironmental history of the tropical Asian and tropical American regions resulted in various origins and evolutionary patterns for the plant lineages with disjunct range in this region, case studies are thus necessary. Ormosia (Leguminosae), containing ca. 130 species, is one of the representatives of tropical Asian-tropical American disjunct plant taxa, its infra-generic phylogenetic relationships and spatiotemporal history are so far unclear. This study will apply improved Hyb-Seq approach of next-generation sequencing to obtain hundreds of low-copy nuclear genes and the chloroplast genome for each species to infer the infra-generic phylogeny of Ormosia; based on the phylogenetic framework, we will estimate the origin-divergence times and ancestral areas of this genus with the integration of the molecular clock results and reliable fossil records; by reconciling the molecular evidence and the ecological niche modeling analyses, we will also investigate the phylogeography of a rare and endangered species, Ormosia henryi, to reinforce the reliability of the generic biogeographical study of Ormosia. Taking Ormosia as an exemplification, this project plans to explore the formation of the tropical Asian-tropical American disjunction in plants. The results can provide a reference to the future studies on the amphi-Pacific evolutionary history of the global tropical/subtropical florae.