不同光照下外源茉莉酸类物质对兴安落叶松防御蛋白的影响

Effects of Exogenous Jasmonic Acid and Methyl Jasmonate on the Defensive Proteins of Larix gmelinii under Different Light Conditions

为了探究光照和外源茉莉酸类物质对兴安落叶松(Larix gmelinii)防御蛋白的协同影响,借助自然光照和遮荫处理,模拟林地自然环境中不同郁闭度下的光照条件。在不同的光照条件下,在落叶松盆栽苗上喷施茉莉酸(JA)和茉莉酸甲酯(Me JA),以喷施蒸馏水为对照,测定落叶松针叶内防御蛋白酶活性的变化。结果表明:遮荫条件下,落叶松针叶内防御蛋白活性均显著高于自然光照下的(p<0.05)。超氧化物歧化酶(SOD)、苯丙氨酸解氨酶(PAL)和胰蛋白酶抑制剂(TI)活性在光照强度为自然光照的25%时达到最大值,过氧化物酶(POD)、多酚氧化酶(PPO)和胰凝乳蛋白酶抑制剂(CI)的活性均在50%光照强度下达到最大值。在相同光照条件下,喷施Me JA和JA后,SOD、PPO和PAL的活性均显著高于对照(p<0.05),POD与蛋白酶抑制剂CI和TI活性在相同光照条件下喷施诱导剂后,显著低于对照(p<0.05)。总体来看,防御蛋白对Me JA的响应强于JA。喷施Me JA和JA后,SOD和PAL在25%自然光照下活性最大,PPO在50%自然光照下活性最大。表明不仅光照和Me JA、JA在单独存在时影响落叶松防御蛋白的活性,而且在光照与Me JA或JA同时存在时对落叶松防御蛋白还存在交互影响。在遮荫条件下喷施Me JA诱导效果优于JA。在生产中适当加大林分的郁闭度,适时喷施外源茉莉酸甲酯,能够提升兴安落叶松的化学防御能力,达到抵御害虫危害的目的。

In order to better understand the induced resistance in larch trees against insects, we studied the potential effect of jasmonic acid and methyl jasmonate on bio-activity of defensive proteins （ induced resistance） in L. gmelinii seedlings un- der the different light conditions. The activities of all the defensive proteins under a shaded condition were significantly higher than those at the natural light intensity （P〈0.05）. The activities of SOD, PAL and TI reached the highest values under the 25% natural light condition, while the activities of POD, PPO and CI reached the highest values at the 50% nat- ural light intensity. After spraying MeJA and JA, the activities of SOD, PPO and PAL under the same light condition were significantly higher than those in CK, but POD, CI and TI were lower than those in CK. The responses from defensive pro- teins to MeJA were stronger than to JA. The protein activity was highest at the 25% light intensity for SOD and PAL, and at the 50% light intensity for PPO. Both two single factors （ light and induce） and their synergistic interaction significantly influence the activity of defensive proteins. Thus, increasing the canopy density and spraying exogenous inducers simulta- neously in practice might increase the induced resistance of L. gmelinii tree against insect attack by increasing the activity levels of their defensive proteins.