中国淡水桥弯藻（Cymbelloid）植物分类学研究

桥弯藻（cymbelloid ）是硅藻植物中的一个主要类群，该类群形态多样，种类繁多，截至目前，世界已报道该类群 4000余种，其属内种间变化极为复杂，各类群分类地位的确立与归属长期以来也存在颇多争议，是硅藻植物中系统分类难度较大的类群之一。本项目在进行广泛野外调查和标本采集的基础上，将对我国桥弯藻植物进行深入系统的分类学研究，利用光镜和扫描电镜对桥弯藻（cymbelloid）进行显微结构特征、超微结构特征以及物种分布特点的研究，为该类群的分类鉴定提供新的分类学依据；同时采用分子生物学的方法构建基于多基因的系统进化树，综合考虑形态学和分子生物学的结论，界定属内种间超微结构分类特征，明确其分类地位及演化关系，提炼各个类群的共同特征，确定分类依据和分类标准，对现有分类学和系统学体系进行修订和完善。分析不同区域桥弯藻植物的生物地理学特点，为我国藻类资源调查和世界桥弯藻分类学研究提供新的资料。

Cymbelloid taxa is a great group in diatom with various morphology, high species diversity, and have a very important position in the evolutionary of diatom. Until now, more 4000 taxa were reported all over the world. This group showed a great genus -level and species-level diversity, many species complex are formed, this group is among the most difficult groups to distinguish. Based on wide field work and accumulate of samples, taxonomic work will be focused on the cymbelloid diatoms from the freshwater habitats of China. The morphology characters will be studied by LM and SEM, new morphological taxonomy features will be provided. Simultaneously, phylogenetic trees will be reconstructed based on multilocus by using molecular biology methods. New taxonomic characters and standards which will modify the modern classification scheme of the diatom will be erected combine the morphological and molecular results. The new data of the distribution of cymbelloid diatom also will be provided for China and the world based on the analyse of biogeographic character of this group.Based on the observation and identification, the morphological taxonomy characters will be summarized, a database of morphology feature of cymbelloid diatom will be established, contain the description of morphological characters and pictures. Combine the morphology and molecular data, the relationship between the genus and species will be re-assessed, new proof will be provided for the systematic classification of cymbelloid diatom. During the investigation, the composition and distribution of freshwater cymbelloid diatom in China will be studied. New species and newly recorded species will be reported, some endemic species will be found. The relationship between the cymbelloid diatom and environmental parameters will be discussed.