Light and nutrient dependent responses in secondary metabolites of Plantago lanceolata offspring are due to phenotypic plasticity in experimental grasslands

A few studies in the past have shown that plant diversity in terms of species richness and functional composition can modify plant defense chemistry. However, it is not yet clear to what extent genetic differentiation of plant chemotypes or phenotypic plasticity in response to diversity-induced variation in growth conditions or a combination of both is responsible for this pattern. We collected seed families of ribwort plantain (Plantago lanceolata) from six-year old experimental grasslands of varying plant diversity (Jena Experiment). The offspring of these seed families was grown under standardized conditions with two levels of light and nutrients. The iridoid glycosides, catalpol and aucubin, and verbascoside, a caffeoyl phenylethanoid glycoside, were measured in roots and shoots. Although offspring of different seed families differed in the tissue concentrations of defensive metabolites, plant diversity in the mothers' environment did not explain the variation in the measured defens...过往已有多项研究表明，以物种丰富度和功能组成为评价维度的植物多样性，可调控植物的防御化学组成。然而目前尚未明确，植物化学型的遗传分化、应对多样性诱导的生长环境变化的表型可塑性，抑或是二者的共同作用，在多大程度上导致了这一观测模式。本研究从植物多样性水平各异的6年生实验草地（耶拿实验，Jena Experiment）中采集了长叶车前草（Plantago lanceolata，ribwort plantain）的种子家系，将这些种子家系的后代置于标准化培养条件下，设置两个光照梯度与两个养分梯度进行培育。本研究测定了植株根系与地上组织中的环烯醚萜苷类化合物梓醇（catalpol）、桃叶珊瑚苷（aucubin），以及咖啡酰苯乙醇苷类化合物毛蕊花糖苷（verbascoside）的含量。尽管不同种子家系的后代在防御代谢物的组织浓度上存在显著差异，但母本所处环境的植物多样性无法解释所测得的防御...