豌豆叶片内源水杨酸和茉莉酸类物质对机械伤害的响应

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

【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SA3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30min,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24h,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。

【Objective】 Effects of mechanical wounding on endogenous jasmonates （JAs） and salicylic acid （SA） were investigated. 【Method】 Pea （Pisum sativum L.） seedlings were used as materials in three treatments including mechanical injury, JAs application and SA application. The contents of endogenous JAs were detected by enzyme-linked immunosorbent assay （ELISA） and the contents of SA by high performance liquid chromatography （HPLC）, and the activities of related enzymes were assayed by spectrophotometer. 【Result】 Endogenous JA rapidly accumulated within 30 min after injury. The increase in the activities of both lipoxygenase （LOX） and allene oxide synthase （AOS） lagged behind JAs burst. A second slight increase in JAs level was observed at 24 h after injury treatment, and at this moment, higher activities of LOX and AOS also were detected. Endogenous free SA content decreased accompanying with JAs burst. The effects of exogenous JA application were similar to those of injury 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 JAs level at the early stage of treatment. 【Conclusion】It is thus suggested that JAs burst and SA decrease in early response to injury may constitute an important mechanism by which plant starts the related defense reaction and adapts to injury stress.