Research on Chromosome Karyotype Analysis of Plumbago auriculata

In this study, the chromosome karyotype of Plumbago auriculata was analyzed by using a chro-mosome mounting technique with the primary root tip of seed germination. The aim was to find out the most suitable method for Plumbago auriculata by comparing the effect of different pretreatment and dissociation time on chromosome. The results showed that the best pretreatment was 0.05% colchicine solution under 0℃ - 4℃ or 2 h and then 1 mol/L HCL under 60℃ water for 6 min. Karyotype analysis of Plumbago auriculata showed that the chromosome number was 12 and the karyotype formula was 2n = 2x = 12 = 8 m (4 sat) 4 sm. The karyotype belonged to 2B and the karyotype asymmetry coefficient was 59.41%. The absolute average length of chromosome was 0.40 μm and the average arm ratio was 1.54. The chromosome of Plumbago auriculata belonged to minichromosome, including a couple of SAT-chromosomes.