外源H2O2对盐胁迫下小麦幼苗生理指标的影响

摘要

In order to determine the effect of hydrogen peroxide on the physiological index of -wheat seedlings under salt stress, wheat (Triticum aestivum L. cv. ' Zhengmai-004') seedlings were treated with hydrogen peroxide, hydrogen peroxide treatment in combination with catalase (CAT) and ascorbate acid (AsA).The results showed that treatments with exogenous H2O2 significantly decreased MDA content, O2 production rate,increased the activities of SOD,POD,CAT, APX and GSH content in wheat seedlings under salt stress, and remarkably promoted wheat seedling growth (plant height, dry weight, root length and root dry weight). The promoting effect of exogenous H2O2 on salt stress could be reversed by the addition of CAT and AsA. It was suggested that exogenous H2O2 induced changes in MDA,O2 -·antioxidant enzymes and antioxidant compounds were responsible for the increase in salt stress tolerance observed in the experiments. Therefore, H2O2 may participate in antioxidant enzymes and antioxidant compounds induced tolerance of wheat seedlings to salt stress. The results also showed that exogenous H2O2 had a positive physiological effect on the growth and development of salt-stressed seedlings.%以‘郑麦-004’小麦幼苗为供试材料,采用Hoagland营养液培养方法,通过添加H2O2的清除剂过氧化氢酶(CAT)和抗坏血酸(ASA),研究0.05 μmol/L外源H2O2处理对150 mmol/L NaCl胁迫下小麦幼苗生长和抗氧化系统活性的影响,探讨低浓度外源H2O2对盐胁迫下小麦幼苗伤害的防护作用及其生理机制.结果显示:外源H2O2能缓解盐胁迫对小麦幼苗生长的抑制效应,降低丙二醛(MDA)含量和超氧自由基(O2-)的产生速率,使小麦幼苗的株高、根长和干重均显著增加,并能提高超氧化物歧化酶( SOD)、过氧化物酶(POD)、CAT、抗坏血酸氧化酶(APX)等保护酶活性和抗氧化物质谷胱甘肽(GSH)的含量;而H2O2清除剂(CAT和AsA)能够逆转外源H2O2对盐胁迫下小麦幼苗生长的促进作用.研究表明,低浓度外源H2O2处理能促进小麦幼苗中的酶类和非酶类抗氧化剂的产生,减少脂质过氧化物的含量,提高小麦幼苗的耐盐性.