用茉莉酸甲酯局部喷施长白落叶松苗对落叶松毛虫体内防御酶的影响

为明确茉莉酸甲酯局部处理林木对落叶松毛虫解毒代谢的影响，本研究以3种不同浓度的茉莉酸甲酯(MeJA，0.01、0.10和1.00mmol/L)局部处理长白落叶松苗的侧枝，分析不同处理对取食其针叶的落叶松毛虫3~5龄幼虫体内保护酶和解毒酶活性的影响。研究发现，3个浓度的MeJA局部处理长白落叶松对松毛虫幼虫体内保护酶和解毒酶活性均有显著影响(P < 0.05)，酶活变化趋势一致，但未呈浓度依赖关系。各处理组幼虫体内的SOD和POD活性均在第4龄显著高于CK(P < 0.05)，但3、5龄幼虫体内的SOD和POD活性与CK差异不显著(P>0.05)；而ACP、AKP和GSTs活性先在第3龄低于CK、第4龄均显著低于CK(P < 0.05)，后在第5龄不同程度地高于CK。表明用MeJA局部喷施能诱导提高长白落叶松的系统抗性，且其对食叶害虫具有广谱性，能干扰落叶松毛虫的解毒代谢，抵御其危害；落叶松毛虫能在逐渐适应后，通过提高保护酶和解毒酶的活性去响应诱导抗性造成的毒害。 

Effects of partially spraying Larix olgensis seedlings with exogenous methyl jasmonate on the defensive enzyme activities of Dendrolimus superans larvae

In order to investigate the effects of exogenous methyl jasmonate on the detoxification metabolism of Dendrolimus superans larvae, three concentrations of methyl jasmonate ( MeJA, 0. 01, 0. 10 and 1. 00 mmol/L) were sprayed partially onto lateral branch of Larix olgensis seedlings; and the protective and detoxification enzyme activities of the 3 rd--5 th instars of Dendrolimus superans larvae that fed on these seedlings were analyzed. Our results showed that exogenous applications ( partial sprays ) of methyl jasmonate at three different concentrations on larch seedlings had significant effects on both the protective and detoxification enzyme activities of Dendrolimus superans larvae ( P<0. 05 ) with similar trends, but were concentration-independent. The SOD and POD activities of the 4th instar larvae in each treatment group were significantly higher than those in CK ( P<0. 05 ) , but the differences were not significant for the 3rd and 5th instars (P >0. 05). The ACP, AKP and GST activities of D. superans larvae in the MeJA treated groups were slightly lower than those in CK at the 3rd instar, and were significantly lower than those in CK at the 4 th instar ( P<0. 05 ) , but were to some extent higher than those in CK at the 5th instar. The above results indicate that partially spraying exogenous methyl jasmonate can increase the induced systemic resistance of Larix olgensis against various defoliators, such as D. superans by disturbing its detoxification and metabolism mechanisms. However, D. superans larvae, in turn, might respond and even adapt to the induced systemic resistance of larch trees by quickly increasing the bio-activities of their protective and detoxification enzymes.