外源茉莉酸甲酯缓解咪唑乙烟酸土壤残留抑制玉米幼苗生长的作用及其机理

Effect of Exogenous Methyl Jasmonate on Mitigating Inhibition of Imazethapyr Residue in Soil to Maize Seedling Growth and Its Mechanisms

为明确外源信号物质茉莉酸甲酯(methyl jasmonate,MeJA)缓解咪唑乙烟酸(imazethapyr,IM)土壤残留对玉米幼苗生长抑制的作用及其机理,本试验采用盆栽法研究MeJA浸种、喷雾处理对IM胁迫下玉米幼苗生长的影响,并通过测定MeJA喷雾处理前后玉米幼苗MDA、叶绿素含量以及SOD、CAT、POD、APX活性的变化探讨MeJA对缓解IM抑制玉米幼苗生长的机理。结果表明,土壤IM残留可显著抑制玉米幼苗生长,其浓度为1.0 mg/kg时可使玉米幼苗株高和鲜重分别降低60.4%和59.6%。MeJA喷雾处理可明显缓解IM对玉米幼苗的抑制,连续5天喷施1.0 mg/L MeJA可使玉米幼苗株高、鲜重分别增加190.0%、361.2%。MeJA喷雾处理可降低IM胁迫下玉米幼苗MDA含量和SOD、CAT、APX活性。综之,喷施外源MeJA可通过降低IM诱导的ROS含量,减少ROS对细胞质膜和叶绿素的破坏,缓解土壤IM残留对玉米幼苗生长的抑制作用。

imazethapyr(IM)residue in soil to growth of maize seedlings and the mechanism of its action,the pot experiment was conducted by setting seed soaking and spraying treatments with MeJA.Their effects on maize seedling growth under IM stress were studied,and the variation of MDA and chlorophyll contents and SOD,CAT,POD and APX activities were analyzed after spraying MeJA in order to explore the mechanism of its action.The results showed that IM residue in soil significantly inhibited the growth of maize seedlings.The height and fresh weight of maize seedlings decreased by 60.4%and 59.6%respectively when the concentration of IM was 1.0 mg/kg.Spraying MeJA obviously mitigated the inhibition of IM to maize seedlings.Spraying MeJA at 1.0 mg/L for five consecutive days increased the plant height and fresh weight of maize seedlings by 190.0%and 361.2%,respectively.In conclusion,spraying MeJA could alleviate the inhibition of IM residue in soil to maize seedlings through reducing the ROS content and damage to cytoplasmic membrane and chlorophyll.