Induction of Zantedeschia hybrid ‘Parfait' polyploid and change of its biological characteristics

Taking in vitro multiple shoot clumps of Zantedeschia hybrid ‘Parfait 'as experimental materials,colchicine and DMSO concentrations and their soaking time during polyploid induction process were analyzed, and differences in leaf indexes, stomatal characteristics, chlorophyll content and chromosome number between polyploid and diploid were compared,finally,the optimal induction condition was confirmed by regression analysis. The results show that with enhancing of colchicine massvolume ratio and shortening of soaking time,survival rate of multiple shoot of different treatment groups increases gradually and is lower than that of the control,while polyploid induction rate decreases gradually and is significantly higher than that of the control. Comprehensively considering factors such as survival rate of multiple shoot and polyploid induction rate and according to regression analysis,the optimal induction condition of Z. hybrid‘Parfait'is soaking multiple shoot clumps in MS liquid medium containing mass-volume ratio 0. 20% colchicine and volume ratio 0. 10% DMSO for 24 h,its polyploid induction rate is up to 50. 02%. The comparison analysis results show that leaf length,leaf thickness and ratio of leaf length to leaf width of polyploid plants are 1. 23,1. 19 and 2. 93 times to those of diploid plants,respectively. Length and width of guard cell and chloroplast number per stoma of polyploid plants are 1. 90,1. 96 and 2. 03 times to those of diploid plants,respectively. Contents of chla and total chlorophyll of polyploid plants are 1. 28 and 1. 17 times to those of diploid plants,respectively. But leaf width and stomatal density of polyploid plants are smaller,which are only 42. 08% and 61. 55% of those of diploid plants,respectively. Except chlb content,there are significant differences in other biological characteristics between polyploid plants and diploid plants. The result of chromosome counting shows that polyploids obtained mostly are tetraploid with chromosome number of 2n = 64,meanwhile,some chimera and hexaploid are obtained. It is suggested that most biological characteristics of Z. hybrid ‘Parfait'polyploids are better than those of its diploids,and the polyploids possess stronger adaptability to environment.