■在入侵地区,人们认为,由于没有天敌,入侵物种减少了对国防的投资。
■通过实地调查和一系列实验室检测,本研究探讨了入侵植物的防御策略。
■实地调查表明,入侵植物对草食性害虫具有拒食作用,本地植物虫洞的分布频率在距入侵物种2-3m的距离处显示出峰值。用两种通才食草昆虫(原生昆虫斜纹夜蛾和入侵昆虫斜纹夜蛾)进行的取食偏好实验表明,入侵植物比本地植物具有更强的拒食作用。通过分析三种入侵植物(Sphgnumticolatrilobata,薇甘菊,Ipomoeacairica)和三种本地植物(Ipomoeanil,Faediafoetida,虎杖),入侵植物的叶子中与防御有关的物质浓度较高,包括总酚,黄酮类化合物,茉莉酸,单宁,H2O2和总抗氧化能力(TAC),和较低的可溶性蛋白质浓度比本地植物。叶子损坏后,与本地植物相比,入侵植物的叶子显示出与防御相关的物质的整体增加,除了可溶性糖。
■这些结果表明,入侵植物在入侵地区保持积极的防御策略,导致草食性昆虫的分布模式以促进入侵的方式发生变化。
UNASSIGNED: In the invaded areas, it is believed that invasive species reduce their investment in defense due to the absence of natural enemies.
UNASSIGNED: By field investigation and a series of laboratory assays, This study explored the defense strategies of invasive plants.
UNASSIGNED: Field investigation indicated that invasive plants have a antifeedant effect on herbivorous pests, and the distribution frequency of wormholes of native plants shows a peak at a distance of 2-3 m from the invasive species. The feeding preference experiment conducted with two generalist herbivorous insects (native insect Spodoptera litura and invasive insect Spodoptera frugiperda) showed that the invasive plants have a stronger antifeedant effect than native plants. By analyzing the content of secondary metabolites in the leaves of three invasive plants (Sphagneticola trilobata, Mikania micrantha, Ipomoea cairica) and three native plants (Ipomoea nil, Paederia foetida, Polygonum chinense), the leaves of invasive plants had higher concentrations of substances associated with defenses, including total phenols, flavonoids, jasmonic acid, tannin, H2O2, and total antioxidant capacity (TAC), and lower soluble protein concentrations than native plants. After leaf damage, compared to native plants, the leaves of invasive plants showed an overall increase in substances associated with defense, except for soluble sugar.
UNASSIGNED: These results suggest that invasive plants maintain active defense strategies in invaded areas, leading to changes in the distribution patterns of herbivorous insects in a manner that facilitates invasion.