摘要
测定了中国锦鸡儿属Caragana各属下分类群20个代表种的ITS、trnL-F和trnS-G序列。基于3种DNA片段的单独分析所获得的系统发育树具有相似的拓扑结构;3种片段的合并分析提高了各分支的支持度,并获得了相似的系统发育树。落轴亚属subgen.Caragana的种类构成了一个在系统树上首先分化出来的单系分支,与形态特征和地理分布的研究一致。短齿系ser.Occidentales和长齿系ser.Bracteolatae的代表种构成了1个单独的分支,因此短齿系应被放入长齿系所属刺叶组sect.Longspina而不是针刺组sect.Spinosae或sect.Pruinosa。分子系统学证据支持依据叶片宽窄在掌叶组sect.Frutescentes中再划分2个系的形态学研究结论;但ser.Dasyphyllae和针刺系ser.Spinosae的亲缘关系较近,系统发育分析的结果似乎不支持在针刺组中单独划分2个系。宿轴类的物种聚成一个单系的分支,因此应被处理为一个组——鬼箭组sect.Jubatae;荚果里面被毛和无毛的种类各自构成2个小支,支持依据该特征在组下分系。系统树显示Sanczir定义的sect.Tragacanthoides显然为多系类群,应将该组中所包含的刺叶组、针刺组、和鬼箭组的种类划分出来。基于ITS的遗传距离表明卷叶锦鸡儿C.ordosica与藏锦鸡儿C.tibetica应该是2个不同的种。
ITS, trnL-F and trnS-G regions of 20 species of Caragana in China were sequenced, and these sampied species covered all recognized subgenera and sections in this genus. Separate phylogenetic analyses of the above DNA fragments generated concordant topologies and a combined analysis of these three datasets significantly improved the statistical supports of all identified clades. Species of subgen. Caragana firstly diverged as a monophyletic group in the phylogenic tree, which was congruent with morphological study and geographical distribution of this taxon. Representative species of ser. Occidentales and ser. Bracteolatae formed one monophyletic clade, indicating that ser. Occidentales should be placed in sect. Longspina, which contains ser. Bracteolatae, but not in sect. Spinosae or sect. Pruinosa. Previous conclusion based on morphology that two series should be defined in sect. Frutescentes according to the shape of leaves was well supported by molecular phylogenetic data in the present study. Because the species of ser. Dasyphyllae had close relationships with those of ser. Spinosae, phylogenetic analysis did not merit the definition of two separate series in sect. Spinosae. Species of Subgen. Jubatae clustered together as a monophyletic clade, and thus should be put in one section, sect. Jubatae. In sect. Jubatae, species having legumina with smooth interior and those producing legumina with haired interior were respectively nested within two separate subclades, corresponding to two series in this section. In the phylogeny tree, sect. Tragacanthoides, defined by Sanczir, was shown to be polyphyletic, suggesting that species of sect. Longspina, sect. Spinosae and sect. Jubatae should be transferred out of this section. Caragana ordosica and C. tibetica had been treated as one species, yet in this study they were proved to be two different species, by genetic distance based on ITS sequences.
出处
《植物分类学报》
SCIE
CSCD
北大核心
2008年第4期600-607,共8页
Acta Phytotaxonomica Sinica
基金
国家自然科学基金(30260010)资助.
