Cluster Analysis of Karyotype and Resemblance-Near Coefficients of Schizonepeta tenuifolia Briq. from Different Producing Origins / 中国药学杂志

ABSTRACT

OBJECTIVE: To explore the karyotype features and genetic relationship among Schizonepeta tenuifolia Briq. from different producing origins. METHODS: The chromosome features of Schizonepeta tenuifolia Briq. from 11 different producing origins were analyzed by using root-tip squashing method and clustered by the karyotype resemblance-near coefficients. RESULTS: The Schizonepeta tenuifolia Briq. from 11 different producing origins all had 12 chromosomes. There were four types of karyotype formula 2n=2x=12=4m+8sm, 2n=2x=12=8m+4sm, 2n=2x=12=6m+6sm and 2n=2x=12=4m+6sm+2st. The karyotypes of Yutianchun and Shanxi Schizonepeta tenuifolia Briq. were 2B type, and those of the other Schizonepeta tenuifolia Briq. were 2A type. The asymmetrical karyotype coefficients were not distinctively different, which ranged from 61% to 67%, and the karyotype of Sichuan Schizonepeta tenuifolia Briq. was the most primitive among all the samples, and the highest degree of evolution belonged to Anguoxia Schizonepeta tenuifolia Briq. The karyotype clustering analysis showed that Jiangsu and Sichuan Schizonepeta tenuifolia Briq had the highest karyotype resemblance-near coefficient (0.989) and the smallest evolutionary distance (0.011). The farthest genetic relationship existed between Zhejiang and Yutianchun Schizonepeta tenuifolia Briq., as shown by the minimum karyotype resemblance-near coefficient (0.792 5) and the maximum evolution distance (0.232 6). CONCLUSION: Karyotype is an important parameter for identification of medicinal plants. The genetic distances between 11 species of Schizonepeta tenuifolia Briq. are obtained by karyotype clustering analysis of karyotype resemblance-near coefficient. The results provide cytological information for the study of germplasms identification, genetic relationship and system evolution of Schizonepeta tenuifolia Briq.