桑天牛危害和外源茉莉酸诱导桑树防御反应的研究

Effects of Apriona germari Feeding-infestation and Exogenous Jasmonic Acid on Induced Defensive Response of Morus L.

通过选择试验研究了桑天牛危害和外源茉莉酸(JA)对于诱导桑树产生防御反应的影响。桑天牛危害诱导的结果表明:在危害诱导后的第3天,受害桑枝被桑天牛继续取食的面积明显少于对照,而同株系统枝被取食的面积与对照间的差异不明显;危害诱导后的第1天,被害桑枝对桑天牛卵啮小蜂的引诱活性显著高于健康桑枝,此后其引诱作用逐渐下降,第3天时与健康桑枝间的差异消失。JA诱导的结果表明:JA处理3 d后,桑枝被桑天牛取食的面积也明显少于对照;JA处理1 d后,桑枝对桑天牛卵啮小蜂的引诱作用明显高于健康桑枝,JA处理2 d后的桑枝对寄生蜂的引诱作用达到了极显著的程度,第3天时与健康桑枝的差异消失。此外,无论是桑天牛危害诱导还是JA处理诱导,对桑天牛的产卵数量均未产生影响。分析认为:桑天牛危害和外源JA均能诱导桑树通过减少桑天牛取食桑枝的面积产生直接防御,但这种抗虫性仅局限于被害桑枝;桑天牛危害和外源JA还通过增强桑枝对桑天牛卵啮小蜂的引诱作用使桑树产生间接防御能力。

The effects of Apriona germari feeding-infestation and exogenous jasmonic acid on induced defensive response of Morus L. were investigated using choice tests. A. germari feeding-infestation test demonstrated that, 3 days after infestation, the feeding-area of A. germari on Morus L. branches was remarkably smaller than that on the control branches, but that on the system branches had no significant difference with that on the control ones. The attractiveness of Morus L. branches to Aprostocetus prolixus 1 day after infestation was significantly higher than that of the control branches. After that, the attractiveness decreased gradually, and the difference in attractiveness to the parasitoid between infested and control branches disappeared within 3 days. Jasmonic acid （JA） induction test revealed that the feeding-area of A. germari on Morus L. branches 1 day after JA application was significantly higher than that on the control branches. The attractiveness of the branches 2 days after JA treatment was extremely significantly higher than that of the control branches, and the difference in the attractiveness to the parasitoid between JA treated and control branches were not significant 3 days after JA application. Moreover, neither infestation nor JA application affected the number of A. germari eggs laid on the branches. All the obtained data showed that feeding-infestation and exogenous JA application can induce direct defense against herbivore by reducing the feeding-area of A. germari on Morus L. branches which is only limited to the infested branch, and indirect defense by enhancing the attractiveness to A. prolixus.