| 摘要: |
| 【目的】探讨氟铃脲对棉铃虫的毒性机制，为苯甲酰基脲类农药在农业生产上的应用以及新农药的研发提供科学依据。【方法】以棉铃虫为材料，研究了氟铃脲对棉铃虫的杀虫活性，探讨氟铃脲处理后对棉铃虫几丁质含量和几丁质酶活性的影响，并采用实时定量PCR技术研究了氟铃脲对几丁质酶基因表达的影响。【结果】供试棉铃虫3龄幼虫经氟铃脲直接浸渍处理后，逐渐表现出反应迟钝、非正常蜕皮以及表皮发育异常等中毒症状，最终畸形死亡。氟铃脲处理后96 h的LC50值为226.43 mg/L，表现出较强的触杀作用以及致畸活性。用氟铃脲120和240 mg/L 处理72 h后棉铃虫3龄幼虫几丁质含量显著降低，并且120 mg/L氟铃脲处理72 h后显著激活了试虫几丁质酶活性，而亚致死质量浓度（60 mg/L）诱导棉铃虫体内几丁质酶活性需要较长的作用时间。实时定量PCR结果表明，氟铃脲(60 mg/L)处理后显著抑制了棉铃虫幼虫几丁质酶基因的表达水平。【结论】氟铃脲对棉铃虫具有较强的毒性作用，能够降低棉铃虫虫体几丁质含量，激活棉铃虫几丁质酶活性，几丁质酶的变化可能与氟铃脲对棉铃虫的毒性有关。 |
| 关键词: 氟铃脲 棉铃虫 生物测定 几丁质 几丁质酶 |
| DOI： |
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| 基金项目:国家自然科学基金项目（31101441）；中央高校基本科研业务费专项（QN2013012） |
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| Toxicity of hexaflumuron and its effects on chitin and chitinase of cotton bollworm,Helicoverpa armigera |
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MA Long,DAI Wu,ZHANG Chun-ni
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| Abstract: |
| 【Objective】This study investigated the toxicity mechanism of hexaflumuron to improve the development and application of benzoylphenylureas (BUPs) based pesticides.【Method】Helicoverpa armigera was used as test insect in this research.The toxicity of hexaflumuron against the larvae of H.armigera was studied,and the effects of exposure to hexaflumuron on chitin content and chitinase activity were analyzed.Additionally,the influence on chitinase gene expression levels was investigated by quantitative Real-time PCR.【Result】3rd-instar larvae of cotton bollworm treated with hexaflumuron showed symptoms including slow response,abnormal molting and abnormal development of cuticle,and dead with malformation finally.Hexaflumuron caused a great contact toxicity and abnormal activity against H.armigera with the lethal concentration of 50% (LC50) of 226.43 mg/L 96 h after treatment.The chitin content of larvae 72 h after being treated by 120 and 240 mg/L hexaflumuron decreased significantly,while the chitinase activities of larvae exposed to 120 mg/L hexaflumuron were significantly activated.It took longer time for 60 mg/L hexaflumuron to activate chitinase activities.Quantitative Real-time PCR analysis showed that the expression levels of chitinase gene (HaCHA) mRNA were significantly decreased after the treatment with hexaflumuron.【Conclusion】Hexaflumuron had strong toxicity against larvae of H.armigera by decreasing the chitin content and increasing chitinase activity.It was inferred that the changes of chitinase may be related to the toxicity of hexaflumuron against H.armigera larvae. |
| Key words: hexaflumuron Helicoverpa armigera insecticidal bioassay chitin chitinase |
