Native herbivory may be detrimental to plant fitness and thus can contribute a biotic resistance to exotic plant invasion. Eupatorium adenophorum, a non-native species, has formed dense monocultures in many southern Provinces of China. Because several native generalist insects feed on E. adenophorum, we evaluated whether the lower level of induced defences and greater compensatory growth contributed to successful invasion of E. adenophorum by comparison with a native congener E. heterophyllum. Early events in the jasmonic acid cascade and chlorophyll fluorescence, non-target metabolomic profiles and recovery in biomass compensation of E. adenophorum and its native congener E. heterophyllum were measured during mechanical wounding and herbivory by the generalist insect Helicoverpa armigera. Mechanical and simulated chewing damage immediately initiated defences in the two species. However, E. heterophyllum was more sensitive to tissue loss, and it produced more metabolic defensive compounds than invasive E. adenophorum. Although H. armigera feeding amplified the effects of mechanical wounding on defence induction, the biomass of E. adenophorum was only weakly affected, as its higher compensatory growth could offset the biomass loss and metabolic cost. Overall, our results suggest that H. armigera herbivory and mechanical wounding could induce different physiological responses, and are often specific to invasive E. adenophorum and native E. heterophyllum. Moreover, lower metabolic defences and higher compensation growth may contribute to the invasion success of E. adenophorum.
摘要:
机械损伤和昆虫取食对紫茎泽兰与本地同属植物防御表达和补偿作用的差异
入侵地群落中的本地草食昆虫取食可以影响植物生长的适合度,从而有助于抵抗外来植物入侵。紫茎泽兰(Eupatorium adenophorum)是一种入侵性很强的外来物种,在中国南方许多省份已形成密集的
单优群落。很多学者认为天敌逃逸是外来植物入侵的一个重要原因,但前期研究发现当地的几种广谱天敌能够取食紫茎泽兰。因此,本研究通过与本地同属植物异叶泽兰(E. heterophyllum)比较,来评估是否
低水平的防御表达和高的生物量补偿促进了紫茎泽兰的成功入侵。本文分别比较了在广谱天敌棉铃虫(Helicoverpa armigera)取食和机械损伤情况下紫茎泽兰和异叶泽兰早期防御信号茉莉酸(JA)和茉莉酸-
异亮氨酸(JA-Ile)、叶绿素荧光、非靶代谢组学特征以及补偿生长等方面的差异。研究结果表明,机械损伤和模拟取食能立即启动入侵植物紫茎泽兰和本地同属植物异叶泽兰的天敌防御,诱导两种植物特异性的生理反馈。异叶泽兰对组织损伤更为敏感,相比于入侵植物紫茎泽兰产生了更丰富的防御化合物。棉铃虫取食比机械损伤对防御诱导的影响更大;与异叶泽兰相比,紫茎泽兰具有较高的补偿生长能力,可以抵消生物量损失和防御成本的投入,受到的影响相对较小。较低的代谢防御和较高的补偿生长可能有助于紫茎泽兰的入侵成功。
关键词:
食草动物取食,
荧光,
代谢,
防御,
补偿,
紫茎泽兰