环境胁迫对大麦幼苗一氧化氮释放的影响

Effects of environmental stress on nitric oxide emission from Hordeum vulgare seedlings.

采用化学发光法定量研究了高温、干旱、盐和重金属(镉和铜)等几种环境胁迫对大麦幼苗内源一氧化氮(NO)释放量的影响。结果表明:短期高温处理可诱导大麦幼苗内源NO释放上升,长期处理则降至对照水平;短期高浓度聚乙二醇6000(25%,30%)处理使植株NO释放量显著增加,但随干旱胁迫时间延长NO释放量有所下降;短期盐胁迫使植株NO释放量增加,长期处理则因盐度不同而有所差异,表现为中低盐度下(≤400mmol.L-1)植株NO释放与对照水平相当,而高盐度下(≥600mmol.L-1)植株NO释放则始终维持较高水平;短期重金属镉和铜处理植株后,植株NO释放与对照差异不大,长期镉处理后,植株NO释放显著升高,而长期铜处理只在低浓度下出现释放高峰。这些结果表明环境胁迫可诱导植物体内NO产生,其NO释放量与胁迫强度和作用时间有一定相关性。

By using chemiluminescence technique, this paper studied the nitric oxide （NO） emission from Hordeum vulgare seedlings under high temperature, drought, salt, and heavy metals （cadmium and copper） stresses. Short-term high temperature stress induced the increase of H. vulgare seedlings NO emission, while long-term high temperature stress dropped the NO emission to the level of the control. Under short-term drought stress, the NO emission from the seedlings treated with high concentration polyethyleneglycol 6000 （25% and 30% ） increased significantly, but under long-term drought, the NO emission decreased. Similarly, the NO emission increased under short-term salt stress, but differed under long-term salt stress, depending on salt concentration, i. e. , kept a lower level similar to the control at low salt concentration （ ≤ 400 mmol · L^-1 ） but maintained at a higher level at high salt concentration （≥ 600 mmol · L^-1 ）. No significant change was observed in the NO emission under short-term heavy metals （cadmium and copper） stress, but the emission increased significantly under long-term cadmium stress and low concentration copper stress. The results suggested that environmental stress induced the NO emission from H. vulgare seedlings, and the emission rate was correlated with the stress strength and stress duration.