干旱胁迫对高山离子芥试管苗抗氧化系统及其活性氧代谢的影响

该试验以高山离子芥试管苗(Chorispora bungeana)为试材,采用固液培养法,设置对照(不添加PEG-6000,CK),轻度干旱胁迫(5%PEG-6000)、中度干旱胁迫(20%PEG-6000)、重度干旱胁迫(40%PEG-6000)4个干旱处理水平,分析干旱胁迫对高山离子芥幼苗抗氧化系统、活性氧代谢等部分生理特征的影响,以揭示高山离子芥在干旱胁迫下的生理响应特征,为进一步探讨其对干旱环境的适应机制奠定基础。结果显示:(1)随着干旱胁迫程度的增加以及在各时间胁迫处理下,抗氧化酶SOD活性及可溶性糖含量显著升高,POD活性、丙二醛含量、CAT活性和APX活性均经历了先升后降的过程。(2)超氧阴离子(O-·2)的产生速率和过氧化氢(H2O2)的含量均显著升高;高山离子芥试管苗叶片相对电导率呈现出升-降-升的变化趋势。(3)相关分析结果显示,MDA与相对电导率、可溶性糖、SOD、APX、O-·2及H2O2呈极显著正相关关系,可溶性糖与SOD、POD、O-·2及H2O2呈极显著正相关关系;相对电导率以及保护酶系均与O-·2、H2O2呈极显著正相关关系。研究表明,高山离子芥具有较强的耐旱性,高山离子芥试管苗在响应干旱胁迫过程中,抗氧化酶系、活性氧代谢、脂质过氧化及渗透调节物等共同参与了高山离子芥试管苗对干旱胁迫的综合抗逆性形成,从而积极启动应对外界干旱环境的耐旱响应机制。

Effect of Drought Stress on Antioxidant System and Reactive Oxygen in Chorispora bungeana Plantlets in vitro

Taking Chorispora bungeana plantlets in vitro as material,we carried out the current study to investigate the effect of drought stress on a Qinhai-Tibet Plateau plant C.bungeana with solid-liquid culture medium.There were four drought levels being Set:the control (without adding PEG-6000,CK),mild drought stress (5% PEG-6000),moderate drought stress (20% PEG-6000),and severe drought stress (40% PEG-6000).The physiological characteristics of C.bungeana seedings in vitro,laying a foundation for adaptation mechanism of C.bungeana in drought environment were investigated.The results showed that:(1)With drought stress became more and more serious,the activity of antioxidant enzyme SOD and soluble sugar content were significantly increased.The SOD peak appeared earlier than that of POD,CAT,and APX.The activities of POD,APX,CAT and MDA content increased at first,and then decreased,which illustrated that all the four enzymes show different responses to drought stress and reactive oxygen species.(2)Hydrogen peroxide(H₂O₂) content and superoxide dismutase(O^-·₂) composition rate in the leaves quantitatively increased with the increase of drought stress over the time course;C.bungeana leaf relative conductivity initially increased,then decreased and increased at last.(3)Correlation analysis showed that,MDA content and the relative electric conductivity,soluble sugar content,SOD,APX activities,O^-·₂ and H₂O₂ contents presented a significantly positive correlation;soluble sugar content and SOD,POD activities,O^-·₂ and H₂O₂ contents presented a significantly positive correlation;the relative electric conductivity and protective enzymes,O^-·₂ and H₂O₂ contents presented significantly positive correlation.The results demonstrated that C.bungeana has a strong drought tolerance,and the membrane lipid peroxidation,osmotic regulator ,antioxidant enzyme system and oxygen reactive participated in the formation of comprehensive drought stress resistance of C.bungeana.And the above physiological indexes have correlations.It partly revealed the physiological mechanism of C.bungeana responding to drought environment.