DISSERTATION RESEARCH: Edaphic factors in the diversification of Ceanothus L., subgenus Cerastes (Rhamnaceae)

这项研究将加深对土壤条件在植物多样性中所起作用的理解。虽然土壤条件长期以来一直被视为植物生态的关键组成部分，但人们对土壤条件对植物进化和多样性的影响知之甚少。这项拟议的研究将使用Ceanothus属植物作为研究土壤条件如何影响多样性的模式系统。天牛含有大量与特殊土壤有关的物种，因此是研究土壤条件对多样性的影响的理想环境。这项拟议的研究将使用遗传数据来确定Ceanothus物种之间的进化关系。然后，这些数据将与土壤化学信息相结合，以推断土壤条件在Ceanothus多样性中所起的作用。拟议的研究将采用跨学科的方法来了解土壤条件如何影响植物多样性，结合进化生物学、生态学和土壤科学学科的数据和分析方法。从这项研究中得出的见解，以及它开发的跨学科方法，将适用于其他植物群体，特别是观察到对土壤条件有很强适应能力的植物多样性的很大一部分。拟议的研究还将增进对北美植物多样性的了解，促进国际合作，在科学界广泛传播研究成果，并通过在加利福尼亚州锡安诺图斯栖息地进行有导游的徒步旅行和面向普通公众的写作等形式的直接外联，造福社会。

This study will improve understanding of the role that soil conditions play in plant diversification. Although soil conditions have long been seen as a key component of plant ecology, little is understood about the effect of soil conditions on plant evolution and diversification. The proposed research will use the plant genus Ceanothus as a model system for the study of how soil conditions affect diversification. Ceanothus contains a large number of species that are associated with unusual soils, and is thus an ideal setting in which to study the influence of soil conditions in diversification. The proposed research will use genetic data to determine evolutionary relationships among Ceanothus species. These data will then be combined with information on soil chemistry to infer the role that soil conditions have played in the diversification of Ceanothus.The proposed research will take an interdisciplinary approach to understanding how soil conditions affect plant diversification, combining data and analytical methods from the disciplines of evolutionary biology, ecology, and soil science. Insights derived from this research, as well as the interdisciplinary approach that it develops, will apply to other groups of plants, particularly the large portion of plant diversity in which strong adaptations to soil conditions are observed. The proposed research will also advance understanding of North American plant diversity, foster international collaboration, result in the broad dissemination of research results within the scientific community, and benefit society through direct outreach in the form of guided hikes in Ceanothus habitats in the state of California, and writings directed at the general public.