灰霉菌侵染对番茄幼苗活性氧积累及抗氧化酶活性的影响

为进一步分析活性氧和抗氧化防御系统在番茄抗病信号调控机制中的作用,为提高产量和品质提供科学依据,以4叶1心的番茄幼苗为试验材料,比较番茄幼苗受灰霉菌侵染后叶片O2^-·以及抗氧化酶、内源褪黑素等的变化。结果表明:番茄幼苗接种灰霉菌后,随着时间的延长,幼苗叶片上病斑斑点逐渐增多,灰霉菌含量显著增多,叶色逐渐变浅,植株表现明显的发病症状;灰霉病菌侵染后番茄体内O2^-·活性爆发,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性下降,过氧化氢酶(CAT)和谷胱甘肽还原酶(GR)活性上升,褪黑素含量增加;上述变化都是番茄幼苗为了抵御灰霉菌的生物胁迫而发生的应激反应。综上,植物在遭受病原菌等生物胁迫时不能简单地推断SOD、CAT和POD等抗氧化酶活性一定升高,植物抵御病原菌侵染更多地依赖于抗性信号路径中信号物质的激活和积累。

Effects of Botrytis cinerea Infection on Active Oxygen Accumulation and Antioxidant Enzyme Activity in Tomato Seedling

Abstract: In order to further analyze the role of active oxygen and antioxidant defense system in the mechanism of disease resistance signal regulation of tomato, and provide scientific basis for improving yield and quality, four-leaf tomato seedlings were used as experimental materials to compare the changes of O2-· , antioxidant enzymes and endogenous melatonin in leaves of tomato seedlings infected by Botrytis cinerea . The results showed that with the prolongation of infection time, the gray mold spots on the leaves of tomato seedlings increased gradually, the relative expression of the B. cinerea gene increased significantly, the color of leaves gradually shallower, and the plants showed obvious disease symptoms. After the infection of B. cinerea , the activities of SOD and POD decreased, the activities of CAT and GR increased, and the content of melatonin increased with the outbreak of O2-· in tomato. The above changes were the stress reactions of tomato seedlings in order to resist the biological stress of B. cinerea . Under biological stress such as pathogenic bacteria, plants could not be simply infered that the activities of antioxidant enzymes such as SOD, CAT and POD must be increased, and the resistance of plants to pathogen infection would depend more on the activation and accumulation of signal substances in the resistance signal pathway.