中国及喜马拉雅地区唐松草属 (毛茛科)的分类学研究

Thalictrum L. (Ranunculaceae) is a large, worldwide genus of approximately 150–200 species, with China and the neighboring Himalayan region being a most important center of species diversity of it. Our understanding of the genus from China and the Himalayan region, however, is far from complete. Numerous species and varieties are poorly defined and their geographical documentation is terribly inaccurate owing to insufficient field studies and because highly variable characters have been used as diagnostic features in the literature, and data of some potentially important microcharacters are rather scanty. Moreover, the current infrageneric classification of Thalictrum is totally morphology-based, not tested yet by comprehensive molecular work. This project is intended to address these problems by using an integrative, multidisciplinary approach. We will start with a critical survey of all the relevant literature and herbarium specimens, and then conduct extensive field observations and in-depth investigations of all the macro- and microcharacters. We will carefully re-evaluate the variation pattern of all these characters and determine their taxonomic utility, and make taxonomic decisions in line with the results of re-evaluation of characters. Based on a thorough species-level revision, we will attempt to perform phylogenetic analyses of Thalictrum using appropriate nuclear and chloroplast DNA fragments, with special reference to those taxa from China and the Himalayan region, and apply the results of phylogenetic analyses, together with evidence from other disciplines, to propose a new arrangement of species. Our major objective is to produce a regional monograph of Thalictrum in the Pan-Himalayan region, which should synthesize all the information that is known about the genus from that region. This project will also build a solid foundation for monographing Thalictrum of the world and conducting investigations on its evolutionary biology and biogeography in the future, and will provide reliable basic scientific information for the utilization and protection of the germplasm resources of the genus, in which many species are medicinally and/or horticulturally important.

毛茛科唐松草属是一世界广布的大属，约包括150–200种，我国及邻近的喜马拉雅地区为其主要的多样性中心。由于野外工作不充分，一些高度可变的性状被用作鉴别特征，以及对具有潜在分类学价值的微观性状的研究不足，因此该属种及变种的界定常不清楚，地理分布记载极不准确。此外，目前唐松草属的分类系统仅基于少数形态性状建立，未经全面的分子系统学分析验证。本项目拟从文献考证和标本检查出发，结合野外和实验室工作，针对我国及喜马拉雅地区唐松草属各主要性状进行深入研究，确定性状的分类学价值，完成种级水平的分类修订，并选取合适的核和叶绿体DNA片段进行系统发育分析，做出种类系统排列。本项目的开展将为完成泛喜马拉雅地区唐松草属的区域性专著提供保证，为以后开展该属的世界性专著编研和进化生物学及生物地理学等方面的深入研究奠定坚实基础，也将为我国植物资源的合理利用和有效保护提供可靠的基础数据。

基于文献考证、标本和野外居群活植物观察以及实验室研究，对我国及喜马拉雅地区毛茛科唐松草属（Thalictrum L.）进行了分类学研究。全面收集了该属的分类学文献，研究了国内外主要标本馆的2万余份标本和大量标本图像，对我国该属植物进行了深入的野外居群观察，采集了80种共450个居群的标本和活材料。根据有关结果，评价了唐松草属植物各主要形态性状的分类价值，确认花序形状、花着生状态（直立/下垂）、花丝形状（线形/棍棒状）、瘦果形状（扁/纺锤形）等特征是属下组、系水平比较可靠的分类性状，植株各部位毛被的有无、小叶形状、萼片大小、雄蕊及心皮大小和数目、心皮（或瘦果）柄的有无等特征是种级水平比较可靠的分类性状。将31个名称处理为异名，将3变种提升为种，描述9新种，最后承认该属在我国共有93种、5亚种、10变种，在泛喜马拉雅地区共有73种、5亚种、8变种。此外还澄清了5个学名错误的异名归置，指定了11个名称的后选模式。对唐松草属60种共171居群进行了细胞学研究，确认唐松草属的染色体基数为x = 7，我国唐松草属植物存在明显的多倍化系列，41种为二倍体（2n = 2x = 14）， 11种为四倍体（2n = 4x = 28），6种为六倍体（2n = 6x = 42），2种为八倍体（2n = 8x = 56），2种为十倍体（2n = 10x = 70）。染色体资料增加了我们对我国唐松草属植物物种形成和分化的理解，也为解决一些形态相似的种类的分类问题提供了重要证据。基于核rDNA ETS和ITS两段序列对唐松草属106种植物开展的分子系统学研究表明目前依靠形态特征建立的属下分类系统并不可靠，未能真正反映不同种类的亲缘关系。本项目首次完成了我国及喜马拉雅地区唐松草属种级水平较全面和深入的修订，为使目前正在编研的《泛喜马拉雅植物志》中唐松草属达到区域性专著水平提供了有力保证,也为我国及喜马拉雅地区该属植物资源的利用和保护（一些种类具有药用或园艺观赏价值）打下了良好基础。