Cipollini Don, Mbagwu Jeanne, Barto Kathryn, Hillstrom Carl, Enright Stephanie
Department of Biological Sciences, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA.
J Chem Ecol. 2005 Jun;31(6):1255-67. doi: 10.1007/s10886-005-5284-3.
The Evolution of Increased Competitive Ability (EICA) hypothesis posits that invasive plants in introduced habitats with reduced herbivore pressure will evolve reduced levels of costly resistance traits. In light of this hypothesis, we examined the constitutive and inducible expression of five chemical defense traits in Alliaria petiolata from four invasive North American and seven native European populations. When grown under common conditions, significant variation among populations within continents was found for trypsin inhibitors and peroxidase activity, and glucosinolates and trypsin inhibitors were significantly jasmonate-inducible across populations. Across populations, constitutive levels of glucosinolates and trypsin inhibitors were negatively correlated with their degree of induction, with three North American populations tending to have lower constitutive levels and higher inducibility of glucosinolates than the seven European populations. Alliarinoside and isovitexin 6"-O-beta-glucopyranoside levels were both higher in North American plants than in European plants, but levels of these compounds were generally increased by jasmonate in European plants and decreased by the same treatment in North American plants. Aside from the tendency for invasive populations to have reduced constitutive glucosinolate levels coupled with increased inducibility, little support for the predictions of EICA was evident in the chemical defenses that we studied.
竞争能力增强进化（EICA）假说认为，在食草动物压力降低的引入栖息地中，入侵植物将进化出成本较高的抗性性状水平降低的情况。根据这一假说，我们研究了来自北美四个入侵种群和欧洲七个本地种群的北美独行菜中五种化学防御性状的组成型和诱导型表达。在相同条件下生长时，发现各大洲内种群间胰蛋白酶抑制剂和过氧化物酶活性存在显著差异，并且在所有种群中芥子油苷和胰蛋白酶抑制剂都能被茉莉酸显著诱导。在所有种群中，芥子油苷和胰蛋白酶抑制剂的组成型水平与其诱导程度呈负相关，北美三个种群的芥子油苷组成型水平往往低于欧洲七个种群，但其诱导性更高。北美植物中的蒜芥苷和异荭草素6″-O-β-葡萄糖苷水平均高于欧洲植物，但在欧洲植物中这些化合物的水平通常因茉莉酸而增加，而在北美植物中相同处理则使其降低。除了入侵种群有降低芥子油苷组成型水平并增加诱导性的趋势外，在我们研究的化学防御中，几乎没有证据支持EICA假说的预测。
