豌豆叶片内源水杨酸和茉莉酸类物质对机械伤害的响应

 【目的】研究内源茉莉酸类（JAs）和水杨酸（SA）对机械伤害的响应特点。【方法】以豌豆幼苗为试材，设置机械伤害、外施茉莉酸（JA）和SA 3个处理，分别采用ELISA、HPLC和分光光度法测定内源JAs与SA含量，及其合成关键酶活性。【结果】伤害处理后30 min，内源JAs含量显著增加，随后迅速下降；JAs生物合成关键酶脂氧合酶（LOX）和丙二烯氧化物合成酶（AOS）活性增加滞后于JAs含量增加。伤害处理后24 h，内源JAs含量又有小幅升高，此时LOX和AOS活性也维持在较高水平。与此相对应，内源自由态SA在JAs突发时呈下降趋势。外源JA处理后内源SA和苯丙氨酸解氨酶（PAL）活性变化同伤害处理相似。外源SA处理初期显著抑制了LOX和AOS活性，同时叶片内源JAs含量降低。【结论】伤害早期内源JAs含量升高和SA含量降低是植物启动相应防御反应和抵御伤害胁迫的重要机制。

Response of Endogenous Salicylic Acid and Jasmonates to Mechanical Injury in Pea Leaves

Abstract: Effects of mechanical wounding on endogenous salicylic acid (SA) and jasmonic acid (JA) were investigated in pea (Pisum sativum L.) leaves. The results showed that endogenous JA rapidly accumulated within 30 min after wounding and then significantly decreased, which is called “JA burst”. The increase in the activities of both lipoxygenase (LOX) and allene oxide synthase (AOS) lagged behind JA burst. A second slight increase in JA level was observed at 24 h after wounding treatment, and at this moment, higher activities of LOX and AOS also were detected. Endogenous free SA content decreased accompanying with JA burst. Effects of exogenous JA application were similar to these of wounding treatment on endogenous SA level and phenylalanine ammonia lyase (PAL) activity, whereas exogenous SA application led to the significant inhibition of LOX and AOS activities and the decrease of endogenous JA level at the early stage of treatment. It is thus suggested that JA burst and SA decrease in early response to wounding may constitute an important mechanism by which plant starts the related defense reaction and adapts to wounding stress.