中国千金藤属（防己科）的分类学研究

The genus Stephania Lour. (Menispermaceae) is dioecious liana, consists of approximately 60 species in the pantropical areas. There are 37 species and 3 varietas (30 endemic) of this genus in China, more than any other country. The taxonomy of Stepnania is controversial, which is due to the difficulty of collection and lack of morphological data. There are many taxonomic questions on it: classification standards of subgenus and groups are different, and classified by subjective judgments; there are also many problems about classification of the endemic and the widely distributed species; some species are doubtfully described, which are even lack of voucher specimens. We prefer to use both morphological and molecular systematic methods to study the phylogeny of Stephania. Morphological characteristics of living plants and specimens will be examined to evaluate the taxonomic importance. Phylogenetic relationships will be investigated by nuclear ribosomal DNA internal transcribed spacer (ITS) sequences，and the chloroplast gene rbcL, matK, trnL-F sequences using maximum parsimony and Bayesian analyses. Morphological data, supplemented by observations of fruits and leaves anatomy and micromorphology, will be used to ascertain evolutionary relationships and confirm generic boundaries. Both morphological data and sequence data will be used to establish a new infrageneric classification of Stephania and determine the exact number of species of Stephania in China. This research will be the foundation of solving the taxonomy problems in Menispermaceae in China, it is also conducive to the protection of the plant resources in this genus.

防己科千金藤属Stephania Lour.是泛热带分布的雌雄异株藤本植物，总数约60种，我国产37种3变种（其中30种为特有种），是拥有种类最多的国家。由于雌雄异株、取材的困难，形态学资料缺乏，千金藤属分类学问题存在争议：属下亚属和组的划分标准不一，且主观判断因素较多；特有种与广布种的分类处理也存在诸多问题；部分种类描述模糊，甚至缺乏凭证标本。本研究拟通过野外调查，结合宏观形态观察，同时借助显微技术观察微型态特征以及解剖学等研究，重新评价并筛选适当的分类性状，进行分支分析，同时进行分子系统学研究，构建系统树，探讨种间亲缘关系，对中国千金藤属进行分类修订。该研究可为中国防己科的分类学研究打下基础，同时有利于对该属植物资源的利用与保护。

防己科千金藤属是泛热带分布的雌雄异株藤本植物，我国是拥有种类最多的国家。这一类群花部结构微小，取材困难。我们主要开展了以下方面的研究：第一，在研究相关文献的基础上查阅标本，并到野外采集相关种类，对中国千金藤属植物进行分类学研究，补充了部分种类的形态学和地理分布资料，同时也发现了近缘类群的新物种；第二，对千金藤属及其近缘种类的叶表皮形态进行观察，认为其形态特征对于属间分类有一定意义，同时发现广泛存在于千金藤属叶表皮的乳突结构可以作为区分其与近缘种类的一个微形态特征；第三，花形态发生研究选取近缘属轮环藤属代表种类与千金藤属的花部发生过程进行比较，发现粉叶轮环藤花瓣的发生始终是合生的，表明了轮环藤属与千金藤属在花部结构分化的初期已经产生了一定差异；第四，千金藤属核果形态尤其是内果皮的形态特征进行研究，表明内果皮纹饰特征在千金藤属的三个亚属中呈现出由简单到复杂的变化趋势；第五，基于ITS和trnL-F的分子系统学研究探讨了千金藤属内以及与近缘类群属间的亲缘关系，表明千金藤属中较为原始的类群与锡生藤亚族的关系更近，其中有争议的马山地不容仍与山乌龟亚属聚在一起。