昌化江河谷对海南岛两种特有植物种群分布与基因流的隔离作用

海南岛是热带生物多样性热点地区之一，但其多样性形成与维持机制尚不清楚。岛上物种多样性最高的中南部山区被海南岛第二大江昌化江及其河谷分割成不连续的三块，可能影响植物种群的分布与基因交流，导致种内或种间分化。本项目选择海南苦苣苔科特有植物毛花马铃苣苔（附生于林下裸石）和盾叶苣苔（阴生于潮湿土壤或石缝），首先研究二者各自地理种群在昌化江河谷两侧生境、种群大小及自然更新等方面可能的差异；然后利用多个叶绿体与核基因片段，分析昌化江河谷两侧地理种群间基因流的方向、强度与遗传分化水平；最后结合石灰岩地貌、季风气候等因子，揭示毛花马铃苣苔和盾叶苣苔在昌化江河谷两侧可能的适应分化及其机制。本项目将揭示昌化江河谷对海南岛植物分布、迁移与适应分化的作用，阐明河流及河谷地理隔离对岛屿特有植物分布与遗传分化的影响规律，有助于深入认识海南岛生物多样性的地理格局成因和特有植物的物种形成与维持机制。

The central-south mountainous regions in Hainan Island are a globally-important biodiversity hotspot of tropical plants, while the evolution and maintenance of such biodiversity remain largely unexplored. The hotspot is divided by a river, Changhuajiang River (the secondly largest river on the island), roughly into three isolated parts, and some species have divided into subspecies between the river. To explore the possible role of geographic isolation caused by Changhuajiang River (valley) on population divergence and gene flows, we choose two Gesneriaceae species endemic to Hainan Island and separated by the Changhuajiang Valley to study the pattern of population distribution, sexual regeneration, and genetic differentiation using both chloroplast and nuclear sequences. The karst topography and tropical monsoon will be also considered to detect mechanisms underlying the possible genetic differentiation and formation of subspecies between the different sides of the valley. This project is expected to reveal the possible role of Changhuajiang River (Valley) on the spread and isolation of plant populations, which will be helpful to understand the distribution, evolution and maintenance of biodiversity on the Hainan Island.