[Objective] This study aimed to provide reference and reduce the workload for screening standard DNA barcoding genes of plants. [Method] Three DNA barcoding genes ITS, ITS2 and rbcL were amplified from seven Xanthium species under the same PCR condition： PCR amplification was started with initial denaturation at 95 ℃ for 4 min, followed by 35 cycles of denaturation at 94 ℃ for 30 s, annealing at 52 ℃ for 45 s, and extension at 72 ℃ for 45 s; the amplification was completed by holding the reaction mixture at 72 ℃ for 10 min to allow complete extension of PCR, and the PCR products were stored at 4 ℃. [Result] Three DNA barcoding genes ITS, ITS2 and rbcL were all amplified successfully. [Conclusion] This study indicates that PCR amplification conditions for DNA barcoding genes ITS,ITS2 and rbcL in plants may be consistent.
