【摘要】 【目的】研究斜纹夜蛾Spodoptera litura幼虫感染莱氏野村菌Nomuraea rileyi后的抗氧化防御机制。【方法】通过测定斜纹夜蛾各龄幼虫超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)等的活性,探讨染菌后不同侵染阶段,幼虫抗氧化酶活性的变化趋势和不同接种方法对抗氧化酶活性的影响。【结果】在斜纹夜蛾染菌幼虫和未接种幼虫(对照)中均未测出POD活性;各龄幼虫在接种莱氏野村菌后SOD和CAT活性显著高于对照,但随着侵染过程的进行,2-3龄幼虫的SOD和CAT活性在16 h左右达峰值后迅速降低,而4-5龄幼虫SOD和CAT活性自染菌初期增强后,变化较平缓,至60-72 h后才低于对照。喷雾法与浸蘸法接种后,各龄幼虫SOD和CAT活性显著高于对照,且对于2-3龄幼虫,浸蘸法对抗氧化酶活性的影响显著高于喷雾法,而对于4-5龄幼虫而言两处理方式之间活性差异不显著。【结论】斜纹夜蛾感染莱氏野村菌后,其体内抗氧化酶活性变化很大,SOD和CAT活性先升后降,且其变化趋势与幼虫所处的发育阶段密切相关。在体壁接种量相当的情况下,浸蘸法对2-3龄幼虫SOD和CAT活性的影响大于4-5龄幼虫。更多还原

【Abstract】 【Aim】This study aims to uncover the antioxidant defense mechanisms in Spodoptera litura larvae infected by the fungus Nomuraea rileyi. 【Methods】We measured the changes in the activities of superoxide dismutase( SOD),catalase( CAT) and peroxidase( POD) in the infected larvae of S. litura at different instars and compared the influences of different inoculation approaches including spraying method and dipping method on antioxidase activities in the infected larvae. 【Results】The POD activity was not detected in both the infected larvae and the non-inoculated larvae( the control) of S. litura. The activities of SOD and CAT in the infected larvae were significantly higher than those in the control at the early stages of infection. However,the activities of SOD and CAT in the infected 2nd and 3rd instar larvae dropped sharply after reaching the peak at 16 h after inoculation. The antioxidase activities in the infected 4th and 5th instar larvae kept a high level for a long time and then turned lower than those of the control at 60- 72 h after infection. The activities of SOD and CAT in the infected larvae which were inoculated with dipping and spraying methods were significantly higher than those of the control,and the dipping method had a greater effect on antioxidase activities than the spraying method in the 2nd and 3rd instar larvae,but there was no significant difference in the effects on the antioxidase activities in the 4thand 5th instar larvae between the two methods. 【Conclusion 】The antioxidase activities in S. litura larvae are greatly affected by the infection of N. rileyi. The activities of SOD and CAT increase first,and then decrease,and the trend of the change is closely related to the developmental stage of the larvae. The dipping method has a stronger influence on the SOD and CAT activities in the 2nd and 3rd instar larvae than on those in the 4th and 5th instar larvae when the body integument inoculation quantities are at the similar level.更多还原