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为了明确活性氧(ROS)在莲子草假隔链格孢Nimbya alternantherae侵染空心莲子草过程中的作用,采用氯化硝基四氮唑蓝(NBT)光化学还原法、二氨基联苯胺(DAB)组织染色法和分光光度法测定了莲子草假隔链格孢SF-193侵染空心莲子草后超氧阴离子(O2﹒-)产生速率、过氧化氢(H2O2)含量、抗氧化酶体系(超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD))活性和丙二醛(MDA)含量。结果显示,接种莲子草假隔链格孢SF-193的叶片经NBT和DAB染色后检测到ROS的大量累积。叶片内的O2﹒-产生速率和H2O2含量随接种时间显著升高,接种后48 h均达到峰值,分别为2.33 nmol.min-1.g-1FW和11.78μmol.g-1FW,是对照的2.1倍和2.5倍;SOD、CAT和POD活性均在接种后8 h达到峰值,分别为277.75、23.47和444.92 U.min-1.g-1FW,之后逐渐下降;MDA含量随接种时间持续上升,72 h时达到峰值,为5.20μmol.g-1FW。表明莲子草假隔链格孢侵染空心莲子草打破了ROS产生与清除之间的平衡,导致植物细胞内的ROS迅速上升,对叶片细胞造成严重破坏。
In order to clarify the role of reactive oxygen species (ROS) during the infection of Alternanthera philoxeroides (Alternanthera philoxeroides) on Alternanthera philoxeroides, photolysis of nitroblue tetrazolium blue (NBT), diaminobenzidine (DAB) Tissue culture and spectrophotometry were used to determine the production rate of superoxide anion (O2.-), the content of hydrogen peroxide (H2O2), the activity of antioxidant enzyme system (SOD), catalase (CAT) and peroxidase (POD)) activity and malondialdehyde (MDA) content. The results showed that a large amount of ROS accumulation was detected in the leaves of A. septempunctata SF-193 after NBT and DAB inoculation. O2 in the leaves. - The production rate and H2O2 content increased significantly with inoculation time and peaked 48 h after inoculation, which were 2.33 nmol.min-1.g-1FW and 11.78μmol.g-1FW respectively, which were 2.1 times and 2.5 times that of the control respectively. The activities of SOD, CAT and POD peaked at 8 h after inoculation, which were 277.75, 23.47 and 444.92 U.min-1.g-1FW respectively, and then decreased gradually. The content of MDA increased with the inoculation time and reached the peak at 72 h, 5.20 μmol.g-1FW. The results showed that Alternanthera philoxeroides infested Alternanthera philoxeroides infested Alternanthera philoxeroides to break the balance between ROS production and clearance, resulting in the rapid increase of ROS in plant cells and severe damage to leaf cells.