Mutations induced from tissue culture are easily to be separated,which might be propagated in the same medium,especially for the color-leaf ornamental grass,Oxalis triaggularis purpurea.Mutations of the ornamental traits in the tissue culture bottle could be investigated easily.The 35 d regeneration system group showed the lowest adventitious bud number and adventitious root number among 4 inoculation dates by 50 Gy dose of 60Coγ radiation.More studies were carded out based on the 35 d differentiation state of O.triangularis purpurea regeneration system.The 35 d regeneration system was then irradiated by 10,25 and 50 Gy doses of 60Coy rays.Numbers of adventitious buds and roots induced from the regeneration system were cut down with the increment of radiation doses.Seedling length was not distinctly reduced at the absorbed doses of 10 and 25 Gy,but reduced distinctly under 50 Gy of 60Coγ irradiation.The optimal irradiation dose for 35 d O.triangularis regeneration system survival and mutation induction was approximately 25 Gy.The M2 phenotypic mutation rate was 2.9％,especially,and the leaf number mutation accounted for 76％ of the total mutation.The phenotypic mutations,especially in the 10 Gy group,on 0.1 mM Vc containing MS medium were recovered,which indicated that ROS plays a key role in the phenotypic mutation induced by 60Coγ-rays.