小秦艽和秦艽核型的比较研究

Comparative Studies on Karyotypes of Gentiana dahurica Fisch and G.macrophylla Pall

目的首次对小秦艽和秦艽的核型进行比较研究,为其遗传和进化提供了进一步的细胞学证据。方法根尖用0.002mol·L-1的8-羟基喹啉溶液预处理5.7h,用2.5%混合酶液,于25℃下酶解1.6h,低渗处理3h(置于冰箱内),然后用空气干燥法制片。结果小秦艽的核型公式是K(2n)=26=2M+24m,属于"1A"型,染色体相对长度组成为2n=26=2L+10M2+12M1+2S;秦艽的核型公式是K(2n)=26=2M+20m+4sm,属于"2B"型,染色体相对长度组成为2n=26=6L+6M2+8M1+6S。结论小秦艽的核型与秦艽相比较,秦艽较为进化。

OBJECTIVE To study karyotypes of Gentiana dahurica Fisch and G. macrophylla Pall for the first time. This will provide cytological evidence for further studies on genetics and evolution. METHODS The root tip was soaked in 0.002 mol-L-1 8-oxychinolin solution for 5.7 h. Then, the sample was decomposed in 2.5% mixed enzyme solution for 1.6 h at 25℃ and treated with Hypotonic for 3 h in refrigerator. At last, specimen slides were prepared by the air-drying technique. RESULTS The karyotypes formula of G. dahurica was K（2n）=2X=26=2M＋24m, which belonged to ＂IA＂ and whose relative length of chromosomes was 2n=26=2L＋10M2＋12M1＋2S. The karyotypes formula of G. macrophylla was K（2n）=2X=26=2M＋20m＋4sm, which belonged to ＂2B＂ and whose relative length of chromosomes was 2n=26=6L＋6M2＋8M1＋6S. CONCLUSION Comparing karyotypes of G. dahurica with G. macrophylla, the result showed that G. macrophylla lives in higher stage of evolution than G. dahurica.