Studies on Introduced Mutagenic Effects of Chronic r—Irradiation on Chrysanthemum
Shen Shoujiang.Wang Yanjun & Zhou Diying (Institute of Utilization of Atomic Energy, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, P.R.China)
Biological and mutagenic effects of chronic r-ray at the doses of 0,2,4,6,8,and10krad on seedlings of chrysanthemum were studied. Results of the study showed that with increasing of irradiation doses the survival rate of transplanted seedlings decreased and the germination of their axillary buds was delayed,the branch number declined as well as the plant growth was retarded.But their damage due to chronic irradiation was significantly lower than that due to acute irradiation. Effects of chronic irradiation on growth of chrysanthemum related with the dose per day also. Under the condition of total dose r-ray at 6krad,axillary bud germination was significantly inhibited by a dose of 600rad/day, while the dose per day less than 300rad had a slight influence. The morphological variation of leaves on VM_1plants causesd by chronic irradiation frequency reached to 20-50%. Variation of flower colour and form inducedby the irradiation had a wide range with a high variation frequency as high as 10.26-13.50%.The mutation frequency of chronic irradiation was more than that of young shoot cutting treated by acute irradation.Most of variants were suitable in VM_2 propagated vegetatively. Its stability depends upon the position of young shoots,at which cutting is selected. Branches from upper stem have higher stability.