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目的探明荆芥核型特征及不同产地来源种质间的亲缘关系。方法以11份不同产地荆芥为材料,采用根尖压片法分析染色体特征,并进行核型似近系数聚类分析。结果 11个产地荆芥的染色体数目均为12,共4种核型公式:2 n=2 x=12=4 m+8 sm、2 n=2 x=12=8 m+4 sm、2 n=2 x=12=6 m+6 sm和2 n=2 x=12=4 m+6 sm+2 st,玉田春和山西荆芥核型属2B型,其他均为2A型。核型不对称系数在61%~67%之间,其中四川荆芥核型最原始,安国夏荆芥进化程度最高。江苏与四川荆芥核型似近系数最高(0.989),核型进化距离最小(0.011),亲缘关系最近;萧山与玉田春荆芥核型似近系数最小(0.792 5),核型进化距离最大(0.232 6),亲缘关系最远。结论核型具有物种稳定性,核型似近系数的聚类分析得出了不同物种间的遗传距离,为荆芥植物资源种质鉴定、亲缘关系和系统演化等研究提供了细胞学基础。
Objective To explore the karyotype of Nepeta and the genetic relationship among germplasm from different origins. Methods 11 samples of Schizonepeta tenuifolia from different areas were used for the analysis of the chromosome features by apical compression method and karyotype similar near coefficient clustering analysis. Results The chromosome numbers of the 11 Schizonepeta tenuipes were all 12, with a total of 4 karyotypes: 2 n = 2 x = 12 = 4 m + 8 sm, 2 n = 2 x = 12 = 8 m + 4 sm, 2 n = 2 x = 12 = 6 m + 6 sm and 2 n = 2 x = 12 = 4 m + 6 sm + 2 st, Yutian Chun and Shanxi Nepeta karyotype belong to type 2B, others are type 2A. The karyotype asymmetry coefficient was between 61% and 67%, among which the most primitive karyotype of Sichuan Nepeta and the highest evolution degree of Nepeta Ann. The karyotypes of Nepeta and Sichuan had the highest similarity (0.989), the smallest karyotype (0.011), and the closest genetic relationship. The karyotypes of Nepean and Xiaoyu were the lowest (0.792 5) and the largest was the karyotype (0.232 6), the most distant relatives. Conclusion Karyotypes have species stability, karyotype similar to the coefficient of clustering analysis obtained the genetic distance between different species, and provided the cytological basis for the germplasm identification, genetic relationship and phylogenetic analysis of Schizonepeta resources.