Adaptability of Different Flue-cured Tobacco Varieties to UV-C Stress Duration

Six popular flue-cured tobacco varieties were cultivated in agar medium under UV-C stress. The growth of the seedlings, the content of photosynthetic pigments, the vigor of root system and the activities of the antioxidant enzymes were determined. The result showed that the fresh weight, the contents of chlorophyll a and chlorophyll b decreased with the treating time prolonged. The content of carotenoid was less than the control group. The rate of reduction decreased with radiation time increased. The ratio of chlorophyll a to chlorophyll b increased. The activities of root dehydrogenase and POD increased while CAT decreased. In conclusion, the descending order of the adaptability to UV-C stress is Yunyan85, Hongda, NC89, K326, Zhongyan98, Yunyan87.