O3污染胁迫下冬小麦的伤害症状及其对叶片氮代谢脯氨酸和谷胱甘肽含量的影响

采用开顶式气室模拟研究O3污染胁迫对冬小麦叶片可见伤害症状、氮代谢、脯氨酸和谷胱甘肽含量的影响,结果表明冬小麦在O3胁迫下表现出明显的受害症状,且O3浓度越高受害症状越严重。O3浓度升高导致不同生长期冬小麦叶片硝酸还原酶活性显著降低,当O3浓度为40～120 nL.L-1时,拔节期、抽穗期和乳熟期的叶片硝酸还原酶活性分别比对照处理降低45.4%～92.9%、58.0%～93.5%和90.0%～93.2%。O3污染胁迫对冬小麦叶片硝态氮和铵态氮含量也有影响,但是随着O3浓度、冬小麦生长期的不同影响不一样;冬小麦叶片脯氨酸和谷胱甘肽含量在O3污染胁迫下变化也各异。在冬小麦抽穗期,当O3浓度为40、80 nL.L-1时,脯氨酸含量分别比对照处理提高163.9%和173.2%,但是在O3浓度为120 nL.L-1时却降低42.4%。O3污染胁迫下拔节期冬小麦叶片还原型谷胱甘肽(GSH)含量显著比对照处理增加,而抽穗期GSH含量在较高O3浓度胁迫下却显著地比对照处理降低,说明植物在O3胁迫下表现出不同的调节和适应机制。

Effects of Ozone Stress on Visible Injury Symptom, Nitrogen Metabolism, and the Contents of Proline and Glutathione in Winter Wheat Leaves

Effects of O3 stress on visible injury symptom,nitrogen metabolism,and the contents of proline and glutathione of winter wheat leaves were studied by open top chambers(OTC).The results showed that O3 stress could induce significant damage to winter wheat leaves and the injury symptom was more serious under higher concentration of O3.The activities of nitrate reductase in leaves of winter wheat reduced with increasing the concentration of O3.Compared to the control treatment,at the O3concentrations of 40~120 nL.L-1,the activities of nitrate reductase decreased respectively by 45.4%~92.9%,58.0%~93.5% and 90.0%~93.2% in the jointing stage,the heading stage and the milk stage of winter wheat.O3stress also had significant effects on the contents of NH4+-N and NO3--N in winter wheat leaves,but the effects were different under different O3 concentrations or different growth stages.The contents of proline and glutathione varied under different O3 concentrations.Compared to the control treatment,proline contents in leaves of winter wheat in the heading stage increased respectively by 163.9% and 173.2% at the O3concentrations of 40 nL.L-1and 80 nL.L-1,while decreased by 42.4% at the O3concentration of 120 nL.L-1.O3 stress resulted in increase of GSH contents in leaves of winter wheat in the jointing stage,while GSH contents in leaves of winter wheat in the heading stage decreased significantly compared with the control group under elevated O3.This study suggests that plants show different adjustment and adaptation mechanism under O3stress.