青藏高原隆升与伴之而来的生物地理屏障形成、水系变迁及第四纪冰期作用深刻影响着高原及其邻近地区植物的物种形成、分化、迁移与分布。小蓝雪花是一种广泛分布于青藏高原、喜马拉雅-横断山及云贵高原中部河谷地带的灌木。本项目拟采集涵盖小蓝雪花整个分布区的居群材料，利用叶绿体和核DNA片断及AFLP分子标记对其进行谱系地理学研究。通过分析其遗传结构、单倍型的空间分布格局和谱系分化时间，追溯其在第四纪冰期-间冰期因气候变迁引起的迁移、扩散的方向和路线及其在青藏高原、喜马拉雅-横断山区的避难所的时空分布，揭示生物地理屏障的形成和水系变迁等历史事件对其遗传结构及现代分布格局的影响，进而为理解青藏高原及其邻近区域的物种分布格局与历史地质、气候变迁之间的关系提供新的证据。

The uplift of QTP and the followed geographical barriers formation, drainage system change, and the climate changes during the Quaternary ice ages, had dramastically affected the speciation, divergence, immigration and distribution of plants on the QTP and in adjacent regions. Ceratostigam minus (Plumbaginaceae) is a riparian shrub widely distributed on the QTP, Himmalaya-Hengduan Mountains and Yunnan-Guizhou Plateau. In this study, we will investigate populations and collect the plant material covering its whole distribution. The phylogeograpical analysis on population genetic structure, spatial pattern of haplotypes, and time of lineage divergence will be conducted by using chloroplast non-coding spacers, nulclear genes and AFLP markers. The route and direction of immigration and expansion, possible refugia on the QTP and or HHM of this species in the glacial and interglacial phases during the Quaternary ice age will be traced. Also, the effect of historic events such as geographical barriers formation and drainage system change following the QTP uplift on the population genetic structure and extant spatial distribution will be postulated. Results of this study will supply proofs for elucidating the correlation between plant distribution and historical geography, climate change, etc. on the QTP and in adjacent regions.