中文摘要：

目的对中药材威灵仙及其易混伪品进行分子鉴定,为控制药材质量稳定和指导临床合理用药提供科学依据。方法以核基因ITS2片段作为DNA条形码,对威灵仙基源植物及其易混品间的种内,种间序列差异进行分析比较,并构建NJ（邻接）树。通过Schultz等建立的ITS2数据库图及其网站预测ITS2二级结构。结果威灵仙基源植物ITS2序列长度分别为220bp和230bp,由所构建的NJ树图可以看出,威灵仙、棉团铁线莲、东北铁线莲聚在一起,支持率达83%;由三种植物的枝长来看,支持了铁线莲属的分布中心在中国云南、四川等西南地区,以中心向四周散布的论点。比较威灵仙及其易混伪品的二级结构发现,威灵仙的正品来源与其它物种在螺旋区茎环的数目、大小、位置以及螺旋臂由中心环伸出时的转角等方面具有较明显区别。结论 ITS2作为DNA条形码序列能够有效的区别威灵仙药材的基源植物与其易混伪品,具有重要的应用价值。

英文摘要：

Objective To discriminate radix et rhizoma clematis and its adulterants,and also assure the quality and clinicalsafety of this traditional Chinese medicinal material.Methods In the study,ITS2 sequence of the clematis and its adulterants were evaluated according to sequence length,GC content,intra-specific variation,as well as the inter-specific divergence.NJ tree of radix et rhizoma clematis its adulterants had been constructed using MEGA4 software.The ITS2 secondary structure was predicted using the ITS2 database and website constructed by Schultz et al.Results The length of ITS2 sequence of the origin plants of radix et rhizoma clematis were 220 bp and 230 bp,respectively.;In the phylogenetic tree,the three origin plants could be clustered together,and the favorability rating was 85 %.From the branches of the plants,the distribution center of the clematis genera in southwesten China conformed with the theory of center spread periphery.The difference between radix et rhizoma clematis and other species could be found in the number,size,position of loop and the angle of helix exsertion based on comparing the ITS2 secondary structure of the origin plants of radix et rhizoma clematis and its adulterants.Conclusion ITS2 can be used to correctly identify radix et rhizoma clematis and its adulterants,and it plays an important role in the identification of traditional Chinese medicine.