Effects Of Water Stress On Active Oxygen Metabolism System And Protective Enzyme Gene Expression Of Sugar Beet

In this experiment, we use two different drought-tolerance cultivars of sugar beet to explore the influence of water stress conditions on active oxygen metabolism system and gene expression of important protective enzyme of sugar beet by using a method of comparative physiology, which applies pot experiment by irrigating 20﹪PEG6000(-0.6Mpa) to simulate water stress conditions. The research results showed: through the treatment of water stress, the antioxidant enzymes activity were higher in Superoxidedismutase(SOD),Peroxidase(POD) and Catalase(CAT)of drought-resistant varieties than in drought-susceptible ones, and relatively stable. The content of Ascorbic acid(AsA)was higher and the content of Carotenoids(Car)was lower in drought-resistant varieties than in drought-susceptible ones. At the same time, the content of superoxide anion radical(O²_-) , hydrogen peroxide(H₂O₂) and malondialdehyde(MDA) in drought-resistant varieties were lower than in drought-susceptible ones. The expression quantity of SOD gene in drought-resistant varieties were more than drought-susceptible ones, but there was not relationship between the expression quantity of SOD gene and the intensity of water stress. The changes of expression quantity of POD gene presented positive correlation with the changes of activity of POD. This research will not only clarify the physiological and biochemical mechanism of resistance to water stress on changes of active oxygen metabolism system and transcriptional level of important protective enzyme ,but also provide a theoretical basis for selecting and breeding physiologically new drought-resistance varieties in sugar beet.