Effect of Colchicine on Polyploid Induction in Explants of Different Grape Variaties
In this study,different concentrations(100、250、500 mg·L-1)of colchicine were used for delayed treatment(1,2,3 days and then cultured for six months)of different types of rootstock'5BB'explants and different table grape varieties.Adventitious buds,embryogenic callus and somatic embryos were used to screen the type of explant suitable for subsequent experiments.The data showed that adventitious buds were more suitable as explants.The seedling growth time after colchicine treatment was the shortest(5 weeks),while the seedling growth times of embryogenic callus and somatic embryos were 22 weeks and 20 weeks,respectively.Then,the same colchicine concentration gradient was used to treat the adventitious buds of'Ruby Seedless''Venus Seedless''Shine Muscat''White Olin'and'Fujiminori'grapevines,the chromosomal doubling effect of colchicine on'Ruby Seedless'regenerated plants and its effect on the characteristics of grapevine plants were tested.The results showed that the survival rate of explants would decline as the colchicine concentration went higher and treatment duration lasted longer.Meanwhile,colchicine treatment significantly delayed the plant regeneration rate,the adventitious buds were the appropriate explant for a great deal of grape chromosome doubling research as they could be obtained easily and regenerate into plantlets within a short time.After colchicine treatment and grown for 1-2 months,the survival rate of'Venus Seedless'and'White Olympia'decreased rapidly,while the survival rate of'Ruby Seedless''Shine Muscat'and'Fujiminori'varieties declined more slowly.The chromosome numbers of plantlets developed from adventitious buds treated with colchicine were improved at different levels,the chromosome doubling grape plantlets containing 112 chromosomes distinctly had larger leaf,longer internode length,higher chlorophyll relative content and higher weight of the root system,although the stem diameter of plants with increased chromosome number was not significantly different from that of the control,the stomatal size of leaves was higher than that of the control,but the stomatal density was significantly decreased.