诱集植物香根草对大螟幼虫营养作用及消化酶的影响

香根草能够有效诱集水稻害虫大螟Sesamia inferens(Walker)在其上产卵,但孵化出的幼虫在香根草上不能完成生活史,香根草对大螟幼虫表现出致死作用。为明确香根草对大螟幼虫致死的作用机制,本研究分析测定了取食香根草后大螟幼虫的营养指标及体内消化酶的变化。结果表明,取食香根草能显著影响幼虫的生长效率及体内消化酶活性。与取食水稻的幼虫相比,取食香根草的幼虫粗生长效率ECI和净生长效率ECD显著降低;除蔗糖酶外,其他消化酶的活性在特定龄期呈显著下降的趋势,具体表现为4龄幼虫蛋白酶比活力、2~4龄幼虫淀粉酶比活力和1~4龄幼虫海藻糖酶比活力显著降低,而1~3龄幼虫蔗糖酶比活力显著提高。本文为进一步阐明香根草对大螟的致死作用机制奠定了基础,为开发以香根草为基础的稻螟绿色防控新技术提供了理论依据。

Effects of Trap Plant Vetiver Grass (Vetiveria zizanioides) on Nutritional and Digestive Enzyme Activities of Pink Stem Borer (Sesamia inferens) Larvae

Vetiver grass (Vetiveria zizanioides) can effectively attract Sesamia inferens to lay eggs,while the larvae can not complete their life cycles by feeding on vetiver,and vetiver exhibits a lethal effect on S.inferens larvae.To understand the lethal mechanism of vetiver against the larvae of S.inferens,we determined the nutritional and digestive enzyme activities of S.inferens larvae feeding on vetiver.The results indicated that vetiver affected the larval growth efficiency and digestive enzyme activities,compared to the larvae feeding on rice.ECI and ECD were significantly decreased in the larvae feeding on vetiver.Except for sucrase,activities of the other digestive enzymes were significantly decreased in some specific stages of larvae feeding on vetiver.The protease activity of the 4 instar larvae,the amylase activities of 2-4 instar larvae and the trehalase activities of 1-4 instar larvae feeding on vetiver were significantly decreased,while sucrase activity of 1-3 larvae was significantly increased compared to the larvae feeding on rice.The findings of this study lay a foundation for further elucidating the lethal mechanism of vetiver against S.inferens,and provide a theoretical basis for the development of sustainable control technology for S.inferens based on the application of trap plant vetiver in rice ecosystem.