广金钱草根尖染色体制片技术及核型分析

目的 建立广金钱草根尖染色体制片方法,为广金钱草染色体数目鉴定提供参考.方法 采用常规压片法制片,以广金钱草根尖为材料,探讨根尖长度、取材时间、预处理方法、解离方法以及染色时间等相关因素对广金钱草根尖染色体制片效果的影响,并进行核型分析.结果 于上午9:00取0.5 cm根尖,0.05%秋水仙素预处理3 h,卡诺固定液固定24 h,1.0 mol/L HCl溶液60 ℃下解离10 min,改良卡宝品红染色20 min,所得根尖染色体制片效果最好.核型分析结果表明,细胞染色体数为2n=2x=22,中部着丝粒染色体(m)为7对,近中部着丝粒染色体(sm)为3对,近端部着丝粒染色体(st)为1对,核型属于2A型,核型不对称系数为60.61%.结论 本研究获得了广金钱草根尖染色体制片最佳技术条件.

Staining and slide-preparing technique of chromosome and karyotype analysis of root-tip in Desmodium styracifolium (Osbeck.) Merr.

Objective To investigate the optimal staining and slide-preparing technique of root-tip chromosome in order to provide references for identification of chromosome numbers in Desmodium styracifolium (Osb.) Merr.Methods The root-tips of D.styracifolium was used to study the effects of root-tip length,sampling time,pre-treating solution,dissociation and staining time on slide-preparing for chromosome and karyotype analysis by using a conventional chromosome mounting technique.Results The mitotic index was the highest and morphology was clear when the root tips length was approximately 0.5 cm at 9:00 AM,then pretreated with 0.05% colchicine for 3 hours,fixed with Carnoy solution for 24 h,and dissociated in 1.0 mol/L hydrochloric acid at 60 ℃ for 10 min.Karyotype analysis of D.styracifolium showed that the chromosome number was 22 and the kayotype formula was 2n=2x=22.7 pairs were metacentric (m),3 pairs were submetacentric (sm),and 1 pair were subtelocentric (st).The kayotype of D.styracifolium was type 2A and the kayotype asymmetry coefficient was 60.61%.Conclusion This study provided the best conditions of chromosome mounting technique for root-tip in D.styracifolium.