蓟马取食、机械损伤以及外源水杨酸甲酯和茉莉酸对菜豆叶片防御酶活性的影响

【目的】探讨菜豆对昆虫取食防御反应的生化机制。【方法】研究了西花蓟马Frankliniella occidentalis取食、机械损伤以及外源水杨酸甲酯（MeSA）和茉莉酸（JA）处理后菜豆叶片防御酶活性的变化。【结果】西花蓟马取食、机械损伤及MeSA和JA处理均能明显提高过氧化物酶（POD）的活性，前2种处理POD活性在72 h上升到最高峰，而后2种处理则在48 h达到最高峰。蛋白酶抑制剂（PI）活性在西花蓟马取食后升高最明显。JA途径关键酶脂氧合酶（LOX）和多酚氧化酶（PPO）的活性在西花蓟马取食、机械损伤和JA诱导处理均升高，但外源MeSA诱导处理则不能诱导它们的活性(P>0.05)。SA途径的关键酶苯丙氨酸解氨酶（PAL）在西花蓟马取食和机械损伤后均有一个先升高后下降的过程，外源MeSA诱导只在24 h引起PAL活性升高，其余时间下和对照没有明显的区别，外源JA诱导未能引起PAL活性的显著变化(P>0.05)。西花蓟马取食、JA和MeSA诱导以及机械损伤均能诱导β-1,3 葡聚糖酶（PR-2）活性上升(P<0.05)。【结论】结果说明，不同处理可诱导菜豆植株产生明显的防御反应，但酶活性的变化与处理方式和处理时间有关。

Effects of thrips feeding,mechanical wounding,and exogenous methyl salicylate and jasmonic acid on defense enzyme activities in kidney bean leaf

【Aim】 To investigate the biochemical mechanisms of defense responses of kidney bean to insect herbivory. 【Methods】 The activities of defense enzymes in kidney bean subjected to feeding by the western flower thrips (WFT), Frankliniella occidentalis (Pergande), mechanical wounding, and treatment of exogenous methyl salicylate (MeSA) and jasmonic acid (JA), respectively, were detected. 【Results】 The results showed that the peroxidase (POD) activities in kidney bean subjected to different treatments increased significantly compared to control. The POD activities induced by F. occidentalis feeding and mechanical wounding reached a peak at 72 h, while those induced by JA or MeSA reached a peak at 48 h. The proteinase inhibitor (PI) activities in kidney bean increased most obviously after thrips feeding. The activities of the key enzymes of JA pathway, lipoxygenase (LOX) and polyphenol oxidase (PPO), increased significantly after F. occidentalis feeding, mechanical wounding and JA induction, respectively, while MeSA did not induce their activities. The activities of phenylalnine ammonialyase (PAL), a key enzyme of SA pathway, increased firstly and then decreased in kidney bean subjected to thrips feeding or mechanical wounding. PAL activity induced by MeSA was significantly higher than the control at 24 h after treatment (P<0.05) but was similar to the control at other treatment time. JA induction failed to cause significant changes of PAL activity (P>0.05). Thrips feeding, JA induction, MeSA induction and mechanical wounding caused β-1,3-glucanase (PR-2) activities to increase significantly (P<0.05). 【Conclusion】 These results indicated that different treatments can induce distinct defense responses in kidney bean, and changes in defense enzyme activities are related to treatment types and treating time.