目的：应用ITS2 条形码序列准确、快速鉴定中药材地黄及其同属密切相关种，以确保该药材的质量及临床用药安全。方法：PCR 扩增产物测序后所得序列经质量分析和拼接，计算地黄及其同属物种的种内、种间K2P 遗传距离，基于K2P 模型构建NJ 树，对地黄药材进行鉴定。结果：地黄药材ITS2 序列长度为231 bp，种内变异较小，平均K2P 遗传距离为0.000 4，地黄药材及其同属密切相关种的种间平均K2P 遗传距离为0.031 2，种间最小K2P 遗传距离大于地黄药材种内的最大K2P 遗传距离。利用构建的NJ 树可以明显鉴定中药材地黄。结论：ITS2 作为条形码可以有效鉴定中药材地黄及其同属的密切相关种，为保障地黄药材的临床安全用药奠定了基础。

Objective: To identify Rehmanniae Radiuxand its closely related species using the ITS2 barcode and to guarantee the quality and clinical curative effect of this medical material. Method: The sequences has been analyzed and assembled using corresponding software. The Kimura 2-Parameter (K2P) distances were calculated and NJ (neighbor-joining) tree was established based on the K2P methods to identify the Rehmanniae Radix. Results:The length of the ITS2 sequence of Rehmanniae Radix was 231 bp. The average intra-specific genetic distances of Rehmanniae Radix were 0.0004. The average inter-specific genetic distances between Rehmanniae Radix and its closely related species were 0.0312. The minimum inter-specific divergence is larger than the maximum intraspecific divergence. The Rehmanniae Radix can be identified using the NJ trees method. Conclusions: The ITS2 sequence can be used as DNA barcode to identify Rehmanniae Radix and its closely related species, which will lay the foundation for the clinical medication safety of Rehmanniae Radix.

科学技术部国家高技术研究发展计划（“863 计划”）项目（2012AA021602）：基于DNA 条形码的珍稀药用、野生等资源快速检测技术及产品开发，负责人：陈士林；国家自然科学基金委面上项目（81073001）：石斛属药用植物DNA 条形码复合序列鉴定研究，负责人：姚辉。