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【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。
【Objective】 The purpose of this study was to explore the biochemical mechanism of the defense response of insects to insects. 【Method】 The changes of defensive enzyme activity of L. japonicus Frankliniella occidentalis fed with mechanical injury and MeSA and JA treatments were studied. 【Result】 The results showed that the activities of peroxidase (POD) were significantly increased after feeding, mechanical injury and MeSA and JA treatments. The activity of POD in the first two treatments increased to its peak at 72 h, while the latter two treatments Peak reached at 48 h. Protease inhibitor (PI) activity increased most significantly after F. occidentalis feeding. The activities of key enzymes, lipoxygenase (LOX) and polyphenol oxidase (PPO), in the JA pathway were all increased in the F. occidentalis fed with mechanical injury and JA induction treatment, but the induction with MeSA could not induce them Activity (P> 0.05). Phenylalanine ammonia-lyase (PAL), a key enzyme in SA pathway, firstly increased and then decreased after feeding and mechanical injury of western flower thrips. The exogenous MeSA induced the increase of PAL activity only at 24 h , And the rest of the time and no significant difference between the control, exogenous JA failed to cause a significant change in PAL activity (P> 0.05). The activities of β-1, 3-glucanase (PR-2) were induced by western food thrips induction, JA and MeSA induction and mechanical injury (P <0.05). 【Conclusion】 The results showed that different treatments could induce obvious defensive responses to bean plants, but the changes of enzyme activities were related to the treatment methods and treatment time.