硅和白粉菌诱导接种对黄瓜幼苗白粉病抗性影响的研究

研究了硅酸盐和诱导接种白粉菌对黄瓜活性氧代谢、SiO2含量和抗病性的影响．结果表明，诱导接种能使叶片的超氧自由基(O2^-)产生速率、H2O2和丙二醛(MDA)含量升高，加硅接种处理的O2^-产生速率、H202和MDA含量明显低于不加硅接种处理．诱导接种能使叶片的过氧化氢酶(CAT)、过氧化物酶(POD)活性升高，超氧化物歧化酶(SOD)活性降低．加硅接种处理植株叶片的CAT、POD和SOD活性明显高于不加硅接种处理．诱导接种提高叶片的抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量，加硅处理的AsA含量明显低于不加硅处理，GSH含量高于不加硅处理．无论接种与否，加硅处理的SiO2含量显著高于不加硅处理，病情指数明显低于不加硅处理．

Effects of silicon supply and Sphaerotheca fuliginea inoculation on resistance of cucumber seedlings against powdery mildew

By the method of hydroponic culture, this paper studied the effects of soluble silicon (Si) supply and Sphaerotheca fuliginea inoculation on the active oxygen metabolism, SiO2 content and disease resistance of a susceptible cultivar. The results showed that the O2*- producing rate and H2O2 and MDA contents of cucumber leaf were increased by Sphaerotheca fuliginea inoculation, but reduced by the inoculation plus Si supply. The inoculation enhanced the catalase (CAT) and peroxidase (POD) activities in plant leaves but decreased their superoxide dismutase (SOD) activity, while inoculation plus Si supply increased the activities of these enzymes. Inoculation increased the scorbate (AsA) and glutathione (GSH) contents in plant leaves. The AsA content in Si-supplied plant leaves was lower than that of Si-deprived ones, whereas the GSH content was in reverse. Whether inoculated or not, the SiO2 content in Si-supplied plant leaves was significantly higher than that of Si-deprived ones. The disease index was significantly decreased by Si-supply.