Radiation-induced Effects On The Rhizomes Of Cymbidium Kanran Makino In Vitro After ⁶⁰Co-gamma Ray Radiation

Using the rhizomes of Cymbidium kanran Makino as materials, we studied the radiation-induced effects of the rhizomes after 60Co-gamma ray radiation. This article mainly describes the influences on proliferation, differentiation and physiological changes of the rhizomes after radiation. The results are as follows:1. As the radiation dose increased, the death rate of rhizomes increased. The median lethal dose was 80.30 Gy. During the late growth stage, the rhizomes were in good condition after a low dose (5-30 Gy) radiation; while after a high dose (60-180 Gy) radiation, all the rhizomes almost showed arrest growth, and most were browning and finally dead.2. Different doses of radiation had a certain impact on the proliferation of the rhizomes. As the radiation dose increased, the absolute growth rate of rhizomes decreased. After the high dose (90-180 Gy) radiation, the absolute growth rate of the rhizomes was less than 5%, and the proliferation of rhizomes had been almost stagnant.3. Different doses of radiation had a certain impact on the differentiation. Rhizomes after low-dose (5-30 Gy) radiation still maintained the activity to form the regenerated plants. There are certain types of variation for the regenerated plants. Variations mainly included the number of leaves reducing, short and weak plant types, leaves etiolating, plants etiolating and so on. When the radiation dose was higher than 30 Gy, irradiated rhizomes although could survive, but failed to form the regenerated plants.4. After different doses of radiation, soluble sugar contents of rhizomes in the radiation group all increased in various degrees compared with the control group. The soluble sugar contents of the irradiation group were significantly different from the control group. After different doses of radiation, soluble protein contents of rhizomes in the radiation group all decreased in various degrees compared with the control group. The soluble protein contents in the 10-180 Gy irradiation group were significantly different from the control group. 5^ After different doses of radiation, MDA and H2O2 contents of rhizomes in the radiation group all increased in various degrees compared with the control group. The MDA and H2O2 contents in the 10-180 Gy irradiation group were significantly different from the control group. After 5-90 Gy radiation, SOD activity of rhizomes increased; while after 120-180 Gy radiation, SOD activity decreased. CAT and POD activity of the rhizomes in all irradiated groups increased in various degrees compared with the control group. APX activity of the rhizomes in 5Gy irradiation group increased.