Mutagenesis effect of 60Co-γ radiation on the annual branches of different fig varieties
[Objective]To explore the influence of 60Co-γ radiation on the mortality rate,antioxidant en-zyme activity and other related physical and chemical indexes of annual cuttings of different fig varieties,and determine the best mutagenic dosage.This study has provided a scientific theoretical basis for the future use of 60Co-γ radiation mutagenesis to improve the genetic diversity of fig,create new germplasm and cultivate new excellent varieties.[Methods]The annual dormant branches of Brunswick and Zhonghuaziguo were used as test materials,and 60Co-γ radiation as the irradiation source,different dosages(0,30,45,60,75 Gy)for radiation treatment were set to observe the changes in the death rate and enzyme activity of branches and leaves caused by irradiation.[Results]With the increase of radiation dosage,the survival rate of cutting seedlings of the two varieties showed a downward trend,and the indexes of plant height,stem diameter,internode length,leaf length,leaf width and branch number showed a downward trend,while the difference of leaf length-width ratio was not significant.The activities of SOD,POD,CAT and other enzymes of Zhonghuaziguo varie-ties showed a trend of increasing first and then decreasing,reaching the peak at the dosage of 45 and 60 Gy,respectively,MDA content showed a trend of increasing all the time,and H2O2 content showed a trend of in-creasing first and then decreasing.The activities of SOD,POD and CAT enzymes of Brunswick varieties de-creased first and then increased with the increase of radiation dose.The content of MDA and H2O2 basically kept rising.[Conclusion]Radiation leads to slow growth of fig cutting seedlings,dwarf plant height,coarse and thin stem and leaves,smaller leaves and fewer branches.It is preliminarily determined that the appropri-ate half lethal dose of Zhonghuaziguo is 56 Gy,and that of Brunswick is 70 Gy.The radiation tolerance of Brunswick is higher than that of Zhonghuaziguo.
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