Phylogenetic Relationships and the Diversification of Photosynthetic Pathways in Eleocharis (Cyperaceae)

有花植物属Eleocharis是莎草科（Cyperaceae）的一个大型且分类学上困难的组，包括分布于世界各地的250多个已描述的物种。 Dr. Eric H.华盛顿州立大学的Roalson和Maurice Ku博士建议对这种多样化的莎草进行彻底的进化研究。 由于这些植物是河岸，湖泊，淡水和半咸水沼泽栖息地的重要生态组成部分，但知之甚少，特别是在热带地区，确定物种的差异和进化模式是至关重要的，以确定这些生态系统中的物种的功能。 特别令人感兴趣的是在属的主要谱系的多样化模式和适应性特征的起源组。荸荠属植物通过多种生理机制在光合作用中捕获能量，通常称为C3、C4和C3-C4中间体。 此外，一些物种能够根据其生长条件改变通过光合作用固定碳的机制。 这些适应性特征的起源尚不清楚，将作为本项目的一部分进行探索。 Roalson和Ku博士将利用DNA变异和物理解剖特征来研究生理过程的多样化模式以及该属中叶解剖学创新的起源。 这些研究也将导致修订的分类和鉴定方法的小组，这将允许更准确地确定物种的分布和特征。这一建议将涉及培训本科生，研究生和研究生的DNA变异，植物解剖学研究，和生物化学研究应用于系统和进化问题。更好地了解一些Eleocharis物种根据其生长条件改变其生物化学和光合作用方法的能力，为未来探索控制光合作用的遗传学提供了极好的机会。 这可能会对目前通过选择和基因改造提高作物产量的努力产生巨大影响。 最后，将通过科学出版物、在国家和国际会议上介绍结果以及开发网络资源，向更广泛的科学界和普通受众传播结果。

The flowering plant genus Eleocharis is a large and taxonomically difficult group of sedges (Cyperaceae) including more than 250 described species distributed worldwide. Dr. Eric H. Roalson and Dr. Maurice Ku at Washington State University propose to conduct a thorough evolutionary study of this diverse group of sedges. As these plants are critical ecological components of riparian, lake, and fresh and brackish marsh habitats worldwide but are poorly understood, particularly in tropical areas, determining species differences and evolutionary patterns is critical to defining the functionality of the species in these ecosystems. Of particular interest are the patterns of diversification of the major lineages in the genus and the origins of adaptive characteristics in the group. Eleocharis species are known to capture energy in photosynthesis through multiple physiological mechanisms, commonly referred to as C3, C4, and C3-C4 intermediate. In addition, some species are able to change the mechanism used for fixing carbon through photosynthesis depending on their growing conditions. The origins of these adaptive characteristics are unclear and will be explored as a part of this project. Drs. Roalson and Ku will use DNA variation and physical and anatomical characteristics to study the pattern of diversification in physiological processes and the origins of leaf-anatomical innovations in the genus. These studies will also lead to a revision of the classification and identification methods in the group, which will allow for more accurate determination of species distributions and characteristics.This proposal will involve training of undergraduate, graduate, and postgraduate students in studies of DNA variation, plant anatomy, and biochemical research applied to systematic and evolutionary questions. Having a better understanding of the ability of some Eleocharis species to change their biochemistry and method of photosynthesis depending on their growing conditions provides an excellent opportunity for the future exploration of the genetics that control photosynthesis. This could have an enormous impact on current efforts in crop plants to increase productivity through selection and genetic modification. Finally, the results will be disseminated to the wider scientific and general audience communities through scientific publication, presentation of results at national and international meetings, and the development of web-based resources.