外源褪黑素对硝酸盐胁迫下番茄幼苗抗氧化系统的影响

以"红粉冠军"番茄为试材,采用灌根方法,研究了0、50、100、150μmol·L^-1外源褪黑素(MT)对75mmol·L^-1硝酸盐胁迫下番茄幼苗丙二醛(MDA)含量、电解质渗透率,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性,抗坏血酸(AsA)和谷胱甘肽(GSH)含量的影响,以期探索外源褪黑素抵御番茄幼苗硝酸盐胁迫的生理机制。结果表明:75mmol·L^-1硝酸盐胁迫下番茄幼苗MDA含量和电解质渗透率逐渐提升,50、100、150μmol·L^-1外源MT缓解幼苗MDA含量和电解质渗透率上升速率,100μmol·L^-1 MT效果最显著。75mmol·L^-1硝酸盐胁迫处理的SOD、POD、CAT和APX活性均高于对照,AsA和GSH含量低于对照,但外源50、100、150μmol·L^-1 MT均能够提高番茄抗氧化酶活性,增加AsA和GSH的含量,提高番茄幼苗硝酸盐胁迫的抗性。100μmol·L^-1 MT激活抗氧化系统效果最显著。

Effect of Exogenous Melatonin on Anti-oxidant System of Tomato Seedlings Under Nitrate Stress

‘Hongfen Champion’tomato was used as test material,the effects of different concentrations(0,50,100,150μmol·L^-1)of exogenous melatonin on MDA content,electrolyte permeability,activities of SOD,POD,CAT,APX,contents of AsA and GSH under 75 mmol·L^-1 nitrate stress were studied by irrigation root method,in order to explore the physiological mechanism of exogenous melatonin on resistance nitrate stress in tomato seedlings.The results showed that MDA content and electrolyte permeability of tomato seedlings increased under 75 mmol·L^-1 nitrate stress,50,100,150μmol·L^-1 exogenous MT relieved MDA content and electrolyte permeability of seedlings,100μmol·L^-1 MT was the best effective.The activities of SOD,POD,CAT and APX under75mmol·L^-1 nitrate stress were higher than those under control,contents of AsA and GSH were lower than control;50,100,150μmol·L^-1 MT increased the activity of tomato anti-oxidant enzyme activity,AsA and GSH contents,improved resistance to nitrate stress in tomato seedlings.100μmol·L^-1 MT had the most significant effect in activating the anti-oxidant system.