水杨酸诱导的月季对甜菜夜蛾的抗性及机理研究

Salicylic Acid-induced Resistance of Rosa chinensis Against Spodoptera exigua and Its Chemical Mechanism

为探明外源水杨酸(SA)诱导月季产生的对甜菜夜蛾的抗性以及产生这种抗性的化学物质基础,采用双选生物测试方法测试了SA处理月季对甜菜夜蛾产卵行为的影响,用GC-MS分析了SA诱导的月季挥发性成分(VOCs)的变化,进一步研究了VOCs中的抗虫活性成分。1.0 mmol/L SA溶液处理月季植株可使甜菜夜蛾在植株上的产卵量显著减少(P<0.05),处理6、9、12 d后,总产卵量与对照相比分别减少了35.4%、38.9%、47.5%。进一步收集对照植株和处理植株顶空挥发性成分,分别配成溶液,喷施两组相同的未经处理的健康月季枝条,结果表明:在喷施了从处理植株上提取的挥发性成分混合物后,枝条上的产卵量与对照相比显著减少(P<0.05),处理6、9、12 d后,抑制指数分别为23.9%、25.4%、36.2%。GC-MS结果表明,SA诱导了月季挥发性成分显著变化。正常情况下2-乙基己酸、十四烷醇、棕榈酸甲酯、乙酸十六酯等化合物在健康植株中不会被合成,只有在SA诱导作用下才会被植株合成出来。SA对这4种化合物的诱导作用表现出明显的时间效应,并且它们对甜菜夜蛾产卵行为的抑制作用表现出明显的浓度效应。结果表明,外源SA处理使月季对甜菜夜蛾产生了诱导抗性,月季挥发性成分变化是这种抗性的重要物质基础。

To determine the exogenous salicylic acid(SA)-induced resistance of Rosa chinensis against Spodoptera exigua, and to explore the chemical mechanism in the resistance, dual-choice bioassays were used to study ovipositional behaviours of S. exigua, and GC-MS was used to determine the changes in SA-induced volatile organic compounds(VOCs) released by S. exigua. The chemicals with their activities to S. exigua were also researched. The ovipositing amounts of S. exigua on the SA-treated R. chinensis decreased significantly(P< 0.05) as a result of the treatment of the plants by SA solution at concentration of 1.0 mmol/l. The total egg numbers decreased by 35.4%, 38.9%, and 47.5% after the treatment for 6 d, 9 d, and 12 d with SA when comparing to the controls, respectively. Furthermore, the VOCs of the control and SA-treated R. chinensis were collected with the method of dynamic headspace absorption(DHSA) and the VOCs solutions were sprayed on the 2 same bouquets of healthy R. chinensis twigs without any treats. The results showed that the amounts of eggs on the twigs sprayed with the mixture of volatiles from SA-treated roses were significantly less than the control roses(P< 0.05). The inhibiting index were 23.9%, 25.4%, and 36.2% after the treatment for 6 d, 9 d, and 12 d, respectively. The GC-MS results demonstrated that the obvious changes in VOCs from R. chinensis were induced by SA treatment. Several chemicals including 2-ethylhexanoic acid, tetradecanol, methyl palmitate, and hexadecyl acetate are not produced naturally by healthy R. chinensis plants, and these chemicals could be produced by R. chinensis only when the plants were induced by SA. Additionally, the induction of SA to the 4 chemicals clearly exhibited temporal effect,and the relations of dosage effects of these chemicals to repel oviposition of S. exigua were recorded clearly in the experiments. The results demonstrated that induced resistance in R. chinensis plant against S. exigua occurs as a consequence of the induction of R. chinensis by SA and the changes in VOCs are responsible for the resistance.