黄体酮对高温下玉米幼苗脂质过氧化及抗氧化酶系统的影响

Effects of Exogenous Progesterone on Lipid Peroxidation and Antioxidant Enzymes of Maize Seedlings under High Temperature Stress

为了探讨外源黄体酮对高温胁迫下玉米幼苗脂质过氧化及抗氧化酶系统的影响,以玉米驻玉309为材料,人工模拟高温条件下采用不同浓度外源黄体酮处理玉米幼苗,研究其电导率、丙二醛(MDA)含量、光合作用放氧速率、叶绿素荧光参数、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性及CAT、SOD同工酶的变化。结果显示,10-9mol/L黄体酮处理玉米幼苗CAT活性为高温处理的2.4倍;10-7mol/L黄体酮处理玉米幼苗SOD、POD活性分别为高温处理的1.1倍、1.2倍;10-9mol/L、10-7mol/L黄体酮处理的幼苗高温下其外渗液相对电导率减少至高温处理的70%和65%,MDA含量减少至高温处理的69%和74%;10-7mol/L黄体酮处理的玉米幼苗其POD、CAT同工酶表达量和放氧速率明显增加,同时叶绿素荧光参数与对照(常温水处理)植株相比也有明显缓解。研究表明,10-9mol/L、10-7mol/L黄体酮处理可以提高高温胁迫下玉米幼苗抗氧化酶的活性及同工酶的表达,降低膜脂过氧化及电解质外渗率,改善光合作用。

To investigate the effect of exogenous progesterone on the activities of lipid peroxidation and antioxidant enzymes,the seedlings of maize（Zea may cv.Zhuyu 309） were pretreated with 10^-9mol / L,10^-7mol / L,10^-5mol / L,10^-3mol / L of progesterone under the high temperature stress.The activities of superoxide dismutase（SOD）,catalase（CAT）,peroxidase（POD）,CAT and POD isozymes,and the malondialdehyde（MDA） content,membrane permeability and chlorophyll fluorescence parameters of maize leaves were assayed.The results showed that,CAT activity of 10^-9mol / L progesterone pretreatment was2.4 times higher than the high temperature treatment,and the activities of SOD and POD of 10^-7mol / L progesterone pretreatment were 1.1 times and 1.2 times higher than the high temperature treatment,respectively.In addition,the relative electric conductivity of 10^-9mol / L and 10^-7mol / L progesterone pretreatment decreased to 70% and 65% of the high temperature treatment,respectively; Malondialdehyde contents were also reduced to 69% or 74% of the high temperature treatment,respectively.The expression levels of POD and CAT isozymes of 10^-7mol / L progesterone treatment elevated,as well as oxygen release rate and chlorophyll fluorescence paraments.This study showed that the pretreatment with 10^-9mol / L and10^-7mol / L progesterone increased the activities of antioxidant enzymes,and decreased the MDA content and the electrolyte leakage rate under high temperature stress,thus to protect the photosynthesis in maize leaves.