青枯雷尔氏菌胁迫对烟草植株抗氧化酶系活性的影响

Effects of Avirulent Ralstonia solanacearum Strain on Some Antioxidant Enzymes Activities in Tobacco Plants

以青枯雷尔氏菌RS-1403作为外源微生物，研究不同浓度青枯雷尔氏菌胁迫对烟草植株叶片PPO、POD、SOD酶活性的影响。结果表明：PPO和POD酶活性总和显著高于对照，而SOD酶活性总和除了处理2（接种浓度为2．35×10^4CFU／mL）外，其余的各个处理的均低于对照。烟草植株的根部、茎部和叶片的POD、PPO和SOD酶活性总和明显高于对照处理，并且其酶活性达到高峰的时间有所不同。胁迫接种5d后，烟草植株叶片和茎部的POD酶活性和对照处理的比值最大，胁迫接种10d后，烟草植株根部POD酶活性比值最大。烟草植株叶片和根部在接种15d后，PPO酶活性和对照处理的比值达到最大，茎部PPO酶活性在接种5d后比值最大。接种20d后，处理烟草植株叶片和茎部的SOD酶活性和对照处理的比值达到最大，接种后25d，根部SOD酶活性比值最大。

Taking Ralstonia solanacearum Rs-1403 as exogenous microorganisms, the effects of avirulent Ralstonia solanacearurn strain RS-1403 on the activities of guaiacol peroxidase （POD; EC 1.11.1.7） ,polyphenol oxidase （PPO; EC 1.30. 3.1） and superoxide dismutase （SOD; EC 1.15.1.1） were investigated in tobacco plants. The results showed that higher levels of total POD and PPO activities were observed in tobacco leaves treated with different concentrations of avirulent R. solanacearum strain RS-1403 compared with control. Total SOD activity of tobacco leaves with different concentrations of avirulent R. solanacearum strain RS-1403 was lower than control except that with the concentration of 2. 35 X 104 CFU/mL. The total POD, PPO and SOD activities of tobacco plants different parts including the roots, leaves and stems were significantly higher than that of control. The times of reaching peak of POD, PPO and SOD activity ratios with that of control in different parts of tobacco plants were different. For the POD activity ratio, it was highest in leaves and stems after 5 d of challenged inoculation and highest in roots after 10 d. PPO activity ratio of leaves and roots reached peak after 15 d. For the stem, it was 5 d. For the SOD activity ratio, it reached highest in leaves and stems after 20 d of challenged inoculation.