颈盲蝽取食对薇甘菊叶片营养物质和防御酶的影响

【目的】薇甘菊是世界最具危害性的入侵杂草之一,对我国生态环境和农业、林业生产造成了严重的危害。颈盲蝽是控制薇甘菊的一种潜在的重要天敌昆虫。本研究旨在探讨薇甘菊被颈盲蝽取食后,叶片防御相关酶系活性、营养物质和叶绿素含量的变化,阐明颈盲蝽取食对薇甘菊生理功能的影响,为利用颈盲蝽防控薇甘菊提供依据。【方法】从云南瑞丽野外采集薇甘菊的本地天敌昆虫颈盲蝽,测定了颈盲蝽取食前及取食12、24、48、96 h后,薇甘菊叶片中过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性,以及可溶性糖、可溶性蛋白及叶绿素含量,以取食前的植株作为对照。【结果】与对照相比,颈盲蝽取食12 h时,薇甘菊叶片中的POD、CAT活性升高,SOD活性降低;之后POD、SOD活性上升,CAT活性降低,取食48 h时,POD和SOD活性达到最高值,CAT活性达到最低值;取食96 h时,POD与SOD活性降低,但仍高于对照,CAT活性与取食48 h时相近。颈盲蝽取食后,薇甘菊叶片中的可溶性糖含量明显上升,取食96 h达到最高值;可溶性蛋白和叶绿素含量显著降低,在96 h达到最低值,分别低于对照39.30%和69.94%。【结论】颈盲蝽取食严重破坏了薇甘菊叶片的正常生理功能,并最终导致其叶片萎蔫和坏疽。

Effects of feeding by Pachypeltis sp. (Hemiptera: Miridae) on the defensive enzymes and nutrients in Mikania micrantha leaves

[Aim] Mikania micrantha is one of the most dangerous invasive weeds in the world, which has caused serious damage to the environment, agriculture and forestry in China. Pachypeltis sp. is a potentially important natural enemy for M. micrantha management. This research aimed for investigating the effects of Pachypeltis sp. feeding on the defense-related enzymes, nutrition and chlorophyll in M. micrantha leaves, which would provide a basis for the management of M. micrantha using the natural enemy Pachypeltis sp.[Method] The local natural enemy Pachypeltis sp. was collected from the field in Ruili City, Yunnan Province, China and was fed with M. micrantha. The activities of peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD), and the contents of soluble sugar, soluble protein and chlorophyll of M. micrantha leaves were determined after 12 h, 24 h, 48 h and 96 h exposure to the mirid; plants not exposed to Pachypeltis sp. served as control.[Result] Compared with the control, the activities of POD and CAT increased and SOD activity decreased in the leaves of M. micrantha after fed by Pachypeltis sp. for 12 h. Afterwards, the activities of POD and SOD increased while CAT activity decreased. The activities of POD and SOD reached the highest values while that of CAT was the lowest at 48 h. The activities of POD and SOD declined after 96 h herbivore exposure, but were still higher than those in the control. CAT activity at 96 h was similar to that at 48 h. After feeding by Pachypeltis sp., the amount of soluble sugar in M. micrantha leaves increased significantly with the highest value at 96 h. The amounts of soluble protein and chlorophyll decreased significantly and reached the lowest values 39.30% and 69.94% lower than the control, respectively, after 96 h exposure to the herbivore.[Conclusion] The natural enemy Pachypeltis sp. would severely damage the normal physiological functions in M. micrantha leaves, causing wilting and gangrene.