Plasticity of a range-expanding Brassicaceae and impact on natural enemies

植物入侵的研究主要集中在跨洋范围扩大的物种上，而忽略了大陆范围内的植物范围扩展。然而，这种大陆内部的射程扩张可能会变得越来越重要，例如，由于气候变化。与横贯大陆的入侵不同，大陆内的范围扩张者可能不会完全被天敌释放，但在物种的本地和非本地分布区，敌人群落可能仍然不同。此外，入侵植物物种可能表现出很高的表型可塑性，并根据场地硝酸盐的有效性而在化学和形态特征上有所不同。在这个项目中，我的目标是：1.测定沿分布范围的范围扩大的植物物种种群的遗传多样性；2.调查植物来源和硝酸盐肥料对根和地上部生长和防御性状的影响；3.评估植物表型差异与相互作用的生物(取食植物、侵染植物的真菌、取根生物)的相关性。作为模式系统，我提出了十字花科植物东方十字花科，它正在向西欧扩展其范围，特别是入侵肥沃和受干扰的地点。为了研究侧柏的遗传变异和表型可塑性，将来自本地、外来和入侵地区的不同种群的植株在两种硝酸盐施肥条件下种植在同一花园中。群体内和群体间的遗传多样性将通过扩增片段长度多态性来确定。将通过测量各种形态和化学参数，以综合方法确定地上部和根部的构成防御和生长模式。在物种内发现的植物防御和生长综合症的差异的相关性将通过两种方式确定。在田间试验中，将连续两年观察到攻击不同植物的食草动物和病原菌群落。在一项实验室研究中，不同来源和不同肥料下生长的植物的抗性将被用叶食草动物、叶病原体和根食草虫作为潜在的拮抗剂来确定。将这个项目的不同部分联系起来，将使我能够确定哪些植物特征对与潜在敌人的互动最具决定性。我假设，高度多样化的植物种群可能是抵御敌人的最好方法，这可能是植物入侵者成功的重要策略。

Biological plant invasions have been studied mainly in transoceanic range expanding species, whereas the range-expansion of plants within continents has been neglected. However, such intracontinental range-expansion may become increasingly important, for example, due to climate change. The intracontinental range-expanders may, in contrast to the transcontinental invasives, not be entirely released by natural enemies, but the enemy community may still differ in the native and non-native distribution areas of the species. Furthermore, invasive plant species may show high phenotypic plasticity and differ in chemical and morphological traits in dependence of the nitrate availability of the site. In this project, I aim to I. determine the genetic diversity of populations of a range-expanding plant species along the distribution range, II. investigate the effects of plant origin and nitrate fertilisation on root and shoot growth and defence traits, and III. evaluate the relevance of differences in plant phenotypes for interacting organisms (shoot-feeders, shoot-infesting fungi, root-feeders). As model system, I propose the Brassicaceae Bunias orientalis, which is spreading its range towards Western Europe and is particularly invading fertile and disturbed sites. To characterise the genetic variation and phenotypic plasticity of B. orientalis, plants of different populations from the native, exotic, and invasive range will be grown in a common garden under two nitrate fertilisation conditions. The genetic diversity within and among populations will be determined by amplified fragment length polymorphism. The constitutive defence and growth pattern of shoots as well as roots will be determined in a comprehensive approach, measuring various morphological and chemical parameters. The relevance of differences in plant defence and growth syndromes found within the species will be determined in two ways. In a field-experiment, the herbivore and pathogen community attacking the different plants will be observed over two consecutive years. In a laboratory study, the resistance of plants from different origin and grown under different fertilisation will be determined using a leaf-herbivore, a leaf-pathogen and a root-herbivore as potential antagonists. Relating the different parts of this project will enable me to determine which plant traits are most decisive for interactions with potential enemies. I hypothesise that highly diverse plant populations may be best defended against enemies and that this may be an important success strategy of plant invaders.