Abstract: | The chromosome numbers, karyotypes and C values of 18 populations of Plantago depressa and 2 populations of Plantago major from the Qinghai Tibet Plateau, China, were reported in the present study. The results were as follows: the chromosome numbers of P. depressa populations from Yadong County and Nyingchi County of Tibetan Autonomous Region (TAR) were 2n=4x=24, other populations of Pdepressa and Pmajor were 2n=2x=12, and the basic chromosome number of all populations was x=6. All karyotype types were 1A, and the karyotype constitutions were not completely consistent with previous reported results. The 2C value of Pdepressa was reported for the first time, and the 1Cx vaule tended to decrease with increasing ploidy levels. Meanwhile, the 2C value of Pmajor was not identical with previous existing results. The results showed that the variation of 2C value occurred at the inter population level of Pdepressa and Pmajor, also flow cytometry couldn′t be used to estimate the ploidy of the genus Plantago Linn. |