中文摘要：

目的：本研究对白头翁、朝鲜白头翁、兴安白头翁3种药用植物及药材进行了形态分类和ITS2序列分子鉴别研究,为建立其分子鉴定方法提供有力依据。方法：通过对长白山区白头翁属3种药用植物进行野外实地考察采样,形态分类描述及提取样品总DNA,扩增ITS2序列、双向测序。所得序列经CodonCode Aligner拼接、比对,采用MEGA 6.0软件对样品进行变异位点分析、计算种内和种间遗传距离（K2P）并构建邻接树（NJ）。结果：形态鉴别容易区分白头翁与朝鲜白头翁和兴安白头翁,但朝鲜白头翁和兴安白头翁不易区分,ITS2序列片段长度均为219 bp,3种药用植物的药材ITS2序列与其基原植物序列一致,种间变异位点有6个,遗传距离显示物种种内最大K2P距离远远小于种间最小K2P距离,NJ树结果显示,白头翁、朝鲜白头翁、兴安白头翁均可明显区分。结论：ITS2序列能够准确鉴定白头翁属3种药用植物的药材和基原植物,可作为形态鉴别的有力补充。

英文摘要：

This study was designed to identify Pulsatilla chinensis,P.cernua and P.dahurica,and carry out their morphological classification and molecular identification.After field investigation and sampling the three medicinal plant species in Changbai Mountain area,morphological characters of the three species were described.The ITS2 sequences were amplified and sequenced bi-directionally.Then the sequences were assembled and compared by CodonCode Aligner.The genetic distances were computed in accordance with the kimura 2-parameter（K2P）,while the NJ tree was built by using MEGA 6.0.Based on morphological characters,P.chinensis can be easily distinguished from P.cernua and P.dahurica,while P.cernua was difficult distinguished from P.dahurica.It was also found that the ITS2 sequences of three medicinal plant species had 219 bp in length,while the medicinal materials and the original plants shared the same ITS2 sequence.There were 6 variations of ITS2 sequences in the three medicinal plant species.The maximum intra-specific genetic distances were lower than the minimum inter-specific genetic distances.The NJ tree exhibited that the three species could be distinguished.All the results demonstrated that the ITS2 sequences could identify the three original plants and medicinal materials of Pulsatilla Mill,accurately,which brought out a useful tool for species identification.