目的 研究能够特异性鉴别鼓槌石斛的PCR引物，并优化PCR检测体系，确立一种快速、准确鉴别鼓槌石斛的方法。方法 从GenBank数据库中下载石斛属rDNA ITS序列170余条，运用MEGA 5.0对所有序列进行同源性比较，找出各变异位点，在非保守区设计1对特异性引物。对35份石斛属植物DNA模板进行特异性引物PCR扩增，显示阳性者为鼓槌石斛。结果 将退火温度升至58 ℃时，鼓槌石斛能被该引物特异性地扩增出来，而其他石斛属植物均为阴性，且该引物的灵敏度可达到0.69 ng/μL。结论 建立一种特异性鉴别鼓槌石斛的方法，运用该特异性引物可实现从同源物种中快速、准确地鉴定出鼓槌石斛，具有特异性好，操作简便、高效、准确等优点。

Objective To design a pair of PCR primers that could identify Dendrobium chrysotoxum specifically, to optimize the system of PCR detection, and to establish a method to identify D. chrysotoxum rapidly and accurately. Methods From GenBank database, rDNA 170 ITS sequences in the plants of Dendrobium Sw. were downloaded and compared with all sequences using MEGA 5.0; The variation sites were located, and a pair of specific primers in the non-conservative district were designed. PCR amplification was performed using the specific primers with 35 DNA templates in the plants of Dendrobium Sw., D. chrysotoxum was positive. Results D. chrysotoxum could be specifically amplificated by specific primers when the annealing temperature was raised to 58 ℃, while other plants of Dendrobium Sw. were shown as negative, and the sensitivity of the primer could reach 0.69 ng/μL. Conclusion This study designs a method that could identify D. chrysotoxum specifically. Using this specific primer could identify D. chrysotoxum rapidly and accurately from the homologous species. This method is well-performed in specificity, and it is more simple, convenient, efficient, and accurate than other methods, such as morphological and microscopical identification, chromatograph, and spectral method.