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期 刊 ：植物保护学报 2011年

关键词：甜瓜；白粉病；苯丙噻二唑；活性氧；抗氧化酶；

Keywords:Cucumis melo, Sphaerotheca fuliginea, BTH, reactive oxygen species, antioxidative enzyme,

摘 要 ：为了明确活性氧(reactive oxygen species, ROS)代谢在甜瓜抗病性诱导中的作用,以抗白粉病甜瓜品种Tam Dew和感病品种卡拉克赛幼苗为材料,通过盆栽试验研究了苯丙噻二唑(BTH)喷雾或白粉菌接种后甜瓜叶片超氧阴离子(O₂^.-)产生速率、过氧化氢(H₂O₂)含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)活性的变化.BTH处理或白粉菌接种均可诱导甜瓜叶片SOD、PAL活性升高,抑制CAT活性,导致叶组织O₂^.-产生速率和H₂O₂含量增加,BTH喷雾+白粉菌接种比二者单独处理效果更好.结果表明,BTH处理后叶片O₂^.-产生速率提高和H₂O₂积累是甜瓜抗白粉病能力提高的重要机制,BTH通过诱导ROS代谢酶活性调节H₂O₂含量,且BTH诱导的甜瓜抗病性与品种的基础抗性有关.

Abstract:To ascertain the role of reactive oxygen species (ROS) metabolism in induction of melon resistance to Sphaerotheca fuliginea after benzothiadiazole (BTH) spraying, seedlings of two melon cultivars, Tam Dew (resistant) and Kalakesai (susceptible) were sprayed with 50 mg/L BTH at five leaf stage, and then inoculated with S.fuliginea seven days later. The production rate of O₂^.-, H₂O₂ content and activities of superoxiede dismutase (SOD), catalase (CAT), phenylalanine amonnialyase (PAL) in leaves were determined. The results showed that the production rate of O₂^.- and H₂O₂ content increased significantly in leaves treated with BTH or S.fuliginea, the activities of SOD and PAL increased while CAT activities decreased after BTH spraying, and better effects were obtained when inoculated with S.fuliginea after BTH spraying than those with BTH or S.fuliginea singly. The increases of O₂^.- production and H₂O₂ accumulation are important mechanisms in resistance increasing of melon to powdery mildew under BTH induction, and H₂O₂ accumulation was due to ROS metabolic enzyme regulation. Melon re- sistance induction is also related to the basic resistance of the cultivars.

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