干旱改变了昆虫取食下琼岛杨(Populus qiongdaoensis)挥发物的排放

Drought stress alters volatile organic compound emissions from Populus qiongdaoensis in response to insect herbivory

生物源挥发性有机化合物(biogenic volatile organic compounds,BVOCs)对于植物抵御生物与非生物胁迫具有重要作用.通过分析琼岛杨(Populus qiongdaoensis)在短期干旱与杨黄卷叶螟(Botyodes diniasalis)单独和双重作用下BVOCs排放的变化,探究单一和双重因子胁迫下植物BVOCs排放的变化.结果显示:(1)正常水分条件下,杨黄卷叶螟(Botyodes diniasalis Walker)对琼岛杨(Populus qiongdaoensis)的叶片的取食面积为23.1 cm2,干旱条件下为18.8cm^(2),干旱降低了杨黄卷叶螟对琼岛杨的叶片的取食,但未达到显著水平(P>0.05).(2)昆虫取食后琼岛杨的单萜类(Monoterpenes)、倍半萜类(Sesquiterpenes)及呋喃类(Furans)BVOCs的排放速率显著上升(P<0.05),与对照相比分别增加37.7%、64.6%和92.1%;干旱胁迫显著降低了呋喃类BVOCs的排放速率(P<0.05),与对照相比降低了51.2%.(3)在干旱胁迫和对照条件下BVOCs的差异主要是干旱抑制苯乙烯排放和干旱刺激癸醛、反式-2-甲基-1,3-戊二烯排放造成的;昆虫取食的植物与对照植物之间的BVOCs差异主要是由于昆虫取食刺激3,4-二甲基呋喃、苯乙醛、2-羟基苯甲醛、苯乙醇、(Z)-2-庚醛、反式-2-甲基-1,3-戊二的排放烯引起的.(4)虽然干旱和昆虫的双重胁迫对琼岛杨BVOCs排放的交互作用并不显著,但干旱和昆虫取食对单萜、倍半萜和呋喃类BVOC排放存在加性效应.比如,昆虫取食增加了呋喃排放,但干旱消除了这种影响.本研究表明,干旱降低昆虫对于琼岛杨叶片的取食;干旱与昆虫取食确实改变了挥发物的排放,但对于不同种类BVOCs的影响不同,并且干旱与昆虫取食之间存在着交互作用.植物BVOCs是植物防御的重要物质,本研究为预估未来由气候变化引起的干旱与昆虫爆发对植物BVOCs排放的影响提供了参考.(图7参38)

Biogenic volatile organic compounds(BVOCs)emitted from vegetation play an important role in plant defense against biotic and abiotic stress.However,the simultaneous response of plant BVOC emissions to biotic and abiotic stressors remains largely unknown.In the present study,we investigated the combined effects of short-term drought and insect herbivory by Botyodes diniasalis on BVOC emissions from the poplar species Populus qiongdaoensis.The results showed that:(1)Under drought and control conditions,the absolute leaf area of P.qiongdaoensis consumed by B.diniasalis larvae was 23.1 and 18.8 cm^(2).Drought reduced the absolute leaf area of P.qiongdaoensis consumed by B.diniasalis,but the results were not significant(P>0.05).(2)The emission rates of monoterpenes,sesquiterpenes,and furans significantly increased by 37.7%,64.6%,and 92.1%,respectively,after P.qiongdaoensis was consumed by B.diniasalis larvae,compared with that under the control conditions(P<0.05).Drought stress significantly reduced the emission rates of furans by 51.2% compared with the levels under the control conditions(P<0.05).(3)Differences in the blend composition between drought-stressed and control plants were primarily driven by drought-suppressed styrene emissions and drought-stimulated decanal and(E)-2-methyl-1,3-pentadiene emissions.In contrast,blend differences between herbivory-damaged and control plants were mainly caused by herbivory-induced emissions of 3,4-dimethylfuran,phenylacetaldehyde,2-hydroxybenzaldehyde,phenylethanol,(Z)-2-heptanal,and(E)-2-methyl-1,3-pentadiene.In summary,drought reduced the absolute leaf area of P.qiongdaoensis consumed by B.diniasalis.Drought and herbivore damage alter volatile emissions;however,the effects vary for different types of BVOCs,and there is an interaction between drought and insect feeding.BVOCs are important components of plant defense systems.This study provides a reference for predicting the effects of climate change-induced drought and insect outbreaks on plant BVOC.