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

生物植物入侵的研究主要集中在跨洋扩展范围的物种，而对大陆内植物扩展范围的研究一直被忽视。然而，由于气候变化等原因，这种大陆内范围的扩大可能变得越来越重要。与横贯大陆的入侵物种相比，大陆内范围扩张者可能不会被天敌完全释放，但天敌群落在物种的本地和非本地分布区域可能仍然存在差异。此外，入侵植物可能表现出高度的表型可塑性，并在化学和形态特征上存在差异，这取决于场地的硝酸盐有效性。在这个项目中，我的目标是：1 .确定沿分布范围扩展的植物物种种群的遗传多样性；研究植物来源和硝态氮施肥对根冠生长和防御性状的影响；评估相互作用生物（取食芽、侵食芽的真菌、取根的真菌）的植物表型差异的相关性。作为模式系统，我建议Brassicaceae Bunias orientalis，它正在向西欧扩张，特别是入侵肥沃和受干扰的地区。为了研究东方桦的遗传变异和表型可塑性，研究人员在不同的硝酸盐施肥条件下，在同一花园中种植了来自本土、外来和入侵地区的不同种群的东方桦。群体内和群体间的遗传多样性将由扩增片段长度多态性决定。将通过测量各种形态和化学参数，以综合方法确定芽和根的组成防御和生长模式。在物种内发现的植物防御和生长综合症差异的相关性将通过两种方式确定。在田间试验中，连续两年观察不同植物的食草动物和病原菌群落。在一项实验室研究中，将使用一种叶食草动物、一种叶致病菌和一种根食草动物作为潜在拮抗剂，来确定来自不同来源和在不同施肥条件下生长的植物的抗性。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性状对与潜在敌人的相互作用最具决定性。我推测，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的重要成功策略。

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.