青藏高原隆升对植物多样性进化的影响－以菊科还阳参亚族类群为例

Research on the dynamic changes in species diversity and the restricted factors of geological history, climate and environment in biodiversity hotspots has motivated growing scientific interest. The uplift of the Qinghai-Tibetan Plateau and changes in ecology and habitats have resulted in the rapid evolution of numerous taxa, resulting in species-rich plant diversity in the region. The Qinghai-Tibetan Plateau holds the key for understanding the correlation between the evolution of species diversity and changes in geological history and the role of climate and the environment in biodiversity hotspots. Therefore, additional studies of the impact of the Qinghai-Tibetan Plateau uplift on the evolution of plant diversity have become very important. Subtribe Crepidinae (Asteraceae) is mainly distributed in eastern Asia, the Qinghai-Tibetan Plateau and adjacent areas. This area is clear the center of diversity of the group. Since the species within this group are already fairly well known, subtribe Crepidinae is an ideal study group for research on the impact of the Qinghai-Tibetan Plateau uplift on evolution and plant diversity. Traditional methods and modern molecular and phylogenetic analyses of biogeography were used to reconstruct the phylogeny and evolution of Crepidinae. Our goal now is to calculate the divergence times and diversification rates of the main clades in the subtribe, then to determine the phylogenetic relationships and spatial and temporal framework within the Crepidinae. By understanding the evolution of the plant diversity, the unevenly distribution, the morphological key innovations and correlating their life histories with the restricted factors of historical geology, climate and environment, we can better understand the mechanisms of evolution of plant diversity on the Qinghai-Tibetan Plateau.

生物多样性热点地区的物种多样性动态变化规律，及其地质历史和环境制约的研究是生物科学和地球科学领域关注的重大科学问题。青藏高原隆升等地质历史事件及其生态环境变迁，使得该区不仅具有丰富的植物多样性，而且众多类群在此快速辐射分化，是研究植物多样性进化，及其与地质环境历史变迁的关联性的重要关键区域。但是青藏高原隆升对物种多样性进化影响研究甚少，所以更深入的研究工作变得非常重要。还阳参亚族是菊科植物少有的以东亚分布为主的类群，并且主要分布和多样性分化中心为青藏高原，是研究青藏高原隆升对物种多样性进化影响的理想材料。本项目在前期研究的基础上，整合系统发育、分化时间、多样化、祖先分布区多学科手段，重建还阳参亚族系统发育和生物地理演化历史，探讨青藏高原还阳参亚族植物的多样化、物种的不均匀分布、形态关键创新与分布海拔、生境和生活型之间的关系，揭示青藏高原植物多样性进化的地质历史和气候环境制约机制。

本项目选取青藏高原及其周边区域类群—还阳参亚族为主要研究对象来探讨青藏高原隆升对植物多样性进化的影响。通过谱系地理学研究，提出区系区划新概念——谱系地理区划和谱系地理小区；通过对合头菊属研究发现这些物种在青藏高原区域除存在着异域分化外，还有正在形成中杂交新种（未形成真正的新种），而青藏高原最后一次隆升及随后而来的第四纪的气候动荡是这个属年轻类群物种分化和杂交事件发生导致较多的共享单倍型出现的主要原因；而对青藏高原及其周边区域特有植物细胞学研究，填补了相关研究类群细胞学研究空白，为相关类群的系统学研究提供了更多的证据，特别是为合头菊属植物的细胞学演化提供了证据，也为华还阳参属的确立提供了细胞学证据支持；构建了还阳参亚族系统发育框架，厘清了亚族下属间关系，确立我国西南地区新属－华还阳参属，同时发表还阳参属新种－沙漠还阳参，发现黄鹌菜属2个新种（待发表）。而且戟叶小苦荬并不属于小苦荬属，而是属于莴苣属（莴苣亚族）。