Effects of ⁶⁰Co-r ray radiation on the growth Speed and chlorophyll content of Begonia tuberhybrida Voss ，Ph．viotlacea Rchb．，Cyclamen persicum Mil1．，Dahlia pinnata Chlav

The effects of ⁶⁰Co-r ray radiation on the growth speed and chlorophyll content of Begonia tuberhybrida Voss．，Ph．viollacea Rchb．，Cyclamen persicum Mil1．，Dahlia pinnata Chlav．are analyzed in this paper．The results show that the 4 kinds of flowers have higher growth speed in the early stage under the condition of low dosage and in the late stage under the condition of high dosage．There is a positive relativity between restraint and radiation dosage and there are higher photosynthesis and fight adverse circum stances for Begonia tuberhybrida Voss． seed ，ph ． viollacea Rchb ，Dahlia pinnata Chlav．ball after the radiation by 10 Gy and Begonia tuberhrida Voss．root，Ph．viollacea Rchb．after the radiation in high dosage．The pattern and petal type of Begonia tuberhybrida Voss．flower have changed by radiation．In further we would get higher decorative flowers and the fine kind of economic value．