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

开花植物Eleocharis是莎草科(莎草科)的一个大类群，包括分布在世界各地的250多个已描述的物种。华盛顿州立大学的Eric H.Roalson博士和Maurice Ku博士提议对这一多样化的莎草群体进行彻底的进化研究。由于这些植物是世界各地河岸、湖泊以及淡水和咸水沼泽栖息地的关键生态成分，但对它们的了解很少，特别是在热带地区，确定物种差异和进化模式对于确定这些物种在这些生态系统中的功能至关重要。特别令人感兴趣的是该属主要谱系的多样化模式和该群体中适应性特征的起源。众所周知，Eleocharis物种通过多种生理机制在光合作用中获取能量，通常被称为C3、C4和C3-C4中间体。此外，一些物种能够改变通过光合作用固定碳的机制，这取决于它们的生长条件。这些适应性特征的起源尚不清楚，将作为该项目的一部分进行探索。Roalson博士和Ku博士将利用DNA变异以及物理和解剖学特征来研究该属植物生理过程中的多样性模式以及叶解剖创新的起源。这些研究还将导致该小组对分类和鉴定方法的修订，这将允许更准确地确定物种分布和特征。这项建议将包括培训本科生、研究生和研究生研究DNA变异、植物解剖学和应用于系统和进化问题的生化研究。更好地了解某些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。这可能会对目前农作物通过选择和基因改造提高生产力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成果以及开发网上资源，向更广泛的科学界和广大受众传播成果。

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.