基于核型分析对芥蓝分类地位的探究

Study on the Classification of Chinese Kale Based on Karyotype Analysis

以芥蓝与甘蓝、白菜、芥菜等8个芸薹属近缘物种为材料,采用常规压片法进行染色体核型分析,结果表明,芥蓝和青花菜、花椰菜、结球甘蓝的核型公式分别为2n=2x=18=10m+8sm (2SAT)、2n=2x=18=10m+8sm (2SAT)、2n=2x=18=8m+10sm (2SAT)、2n=2x=18=6m+12sm (2SAT),核型类型均为2A型;大白菜和小白菜核型公式为2n=2x=20=14m (2SAT)+6sm、2n=2x=20=16m (2SAT)+4sm,核型类型均为1B型;雪里蕻、榨菜核型公式为2n=2x=36=22m+14sm (2SAT)、2n=2x=36=26m+10sm (2SAT),核型类型均为2B型;芥蓝的核型在核型类型、核型不对称系数、臂比、随体分布染色体类型等核型特征上与甘蓝类高度类似,与白菜类和芥菜类差异较大。芥蓝的核型进化程度位于青花菜与花椰菜、结球甘蓝之间,与白菜类和芥菜类相距较远。因此,本试验结果支持芥蓝为甘蓝种的一个变种。

Chromosome karyotype analysis of eight Brassica species of Brtissica oleracea, Brassica canipestris, Brassica juncea and Chinese kale were carried out by conventional pressing method. The results showed that the karyotype formulas of Chinese kale, broccoli, cauliflower and cabbage were 2n=2x= 18= 10m+8sm (2SAT), 2n=2x= 18=10m+8sm (2SAT), 2n=2x=18=8m+10sm (2SAT), and 2n=2x= 18=6m+12sm (2SAT), respectively, and karyotypes were 2A type. The karyotype formulas of Chinese cabbage and pakchoi were 2n=2x=20=14m (2SAT)+6sm and 2n=2x=20=16m (2SAT)+4sm, respectively, and karyotypes were IB type. The karyotype formulas of potherb mustard and tuber mustard were 2n=2x=36=22m+14sm (2SAT) and 2n=2.r=36=26m+1 Osm (2SAT), respectively, and karyotypes were 2B type. Chinese kale had high similarity with B. oleracea on karyotype type, asymmetrical karyotype indexes, chromosome arm ratio, satellite chromosome type, and so on, whereas it was obviously different with B. campestris and B. juncea. The karyotype evolution of Chinese kale was located between broccoli and cauliflower and cabbage, and was far away from B. campestris and B. juncea. Therefore, the results of this study supported that Chinese kale should be a variant of B. olercwea.