菊花γ-射线慢照射的诱变效果研究

Studies on Introduced Mutagenic Effects of Chronic r—Irradiation on Chrysanthemum

菊花苗期经0、2、4、6、8、10krad的γ射线慢照射处理,随辐照剂量增加,显示移栽成活率降低,腋芽萌发延迟,分枝减少,植株生长受到抑制。但其辐射损伤比急性照射明显减轻。慢照射对菊花生长的影响与日照量有关,在总剂量6krad下,每日照射量600rad时,明显抑制了腋芽萌发,300rad以下时,则影响轻微。慢照射引起的VM_1代叶片形态变异出现的频率达20—50％,诱发出现的花色花型变异谱广,变异频率高,经4—10krad剂量处理,花色花型变异频率达10.26—13.5％,比常用的嫩枝插条照射的突变率高得多。上述变异通过无性繁殖在VM_2代中大部分是稳定的,其稳定性与VM_2扦插嫩枝取材部位有关,突变株上部茎抽生的嫩枝稳定度高。

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.