Abstract:

The root tips of Iris tigridia were used to study the effects of sampling time, pre-treating solution and dissociation time on slide-preparing for chromosome and karyotype analysis. The aim was to provide the references for its cytology research and crossbreeding. The results showed that the optimal sampling time of root tips was 8:00-11:00 am in the field. The best process of staining and slide-preparing technique was that the root tips were pretreated 2.5 h with 2 mmol/L 8-hydroxy quinoline solution, and then it was fixed with Carnoy solution for 2 h, associated with 5 mol/L HCl for 10 min at room temperature and stained with Carbol fuchsin solution. The chromosome number of Iris tigridia was 2n=18. Karyotype formula was 2n=2x=18=2M+10m+6sm. The karyotype classification belonged to 2A type.