NO对百草枯胁迫下玉米胚根氧化损伤的效应

Effects of Treatment of Nitric Oxide(NO) on Active Oxygen Species Damages in Maize Radicle under MV Stress

比较不同浓度百草枯(即甲基紫精,MV)、外源NO供体硝普钠(SNP)处理以及SNP和MV交互处理条件下玉米胚根活性氧代谢的变化。结果表明:分别用50,100,150μmol/L的MV溶液处理萌发玉米,MV浓度50μmol/L是诱导玉米胚根活性氧“迸发”的适宜浓度,选择50μmol/L MV与SNP进行交互处理。不同浓度SNP处理玉米胚根时,其CAT,SOD,POD活性呈现“降→升→降”的变化趋势。低浓度SNP处理使H2O2含量减少、O-2产生速率降低,高浓度SNP则促进其累积,表明低浓度SNP处理有缓减活性氧形成的作用。50μmol/L MV与不同浓度SNP交互处理萌发玉米,其CAT,POD,SOD活性增强,H2O2,MDA含量和O-2产生速率降低,且O2-产生速率与SOD活性变化、CAT活性变化与H2O2含量变化存在一定的相关性,表明一定浓度的SNP具有抵御MV氧化胁迫的作用。证实了NO对百草枯胁迫下玉米胚根的氧化胁迫具有明显的缓解作用。

The effects of defensive enzyme activities （CAT, SOD, POD ）, H2O2 contents, O2^-production and MDA contents in maize radicle treated respectively with different concentration methyl viologen （MV）, sodium nitroprussise （SNP）, and synchronously with SNP-MV were studied. The results showed that an appropriate MV concentration was 50 μmol/L under which the spurt of active oxygen was induced. When the maize radicle was treated with different concentration SNP, the activities of CAT, POD and SOD took on the diversification of ＂drop-ascend-drop＂. The forming of active oxygen was alleviated under low SNP concentration. Compared with the maize radicle treated with SNP, the defensive enzyme activities were increased in maize radicle treated synchronously with 50 mol/L MV and SNP, H2O2 and MDA contents and Of productivity were decreased. The changes between H2O2 and CAT,O2^- and SOD had the definite relativity. It was suggested that NO may obviously alleviate the accumulation of active oxygen species in the maize radicel under tress of MV.