DISSERTATION RESEARCH: Metabolic Bet Hedging as an Explanation for Maintenance of Diverse Tree-Ectomycorrhizal Mutualisms

许多植物依靠与被称为菌根的地下真菌的互惠互利的相互作用来收集营养、提供水和防御害虫，以换取植物提供的能量。一株植物可能同时拥有几十种不同种类的菌根，包括一些看起来几乎没有好处，甚至可能有害的菌根。该项目提出了代谢下注对冲的想法，以解释单个树木维持的菌根的多样性。由于树木经历了明显的季节和年际环境变化，它们的营养需求也随着时间的推移而变化，这可能会改变每种真菌伴侣的相对价值。由于人类投资者维持股票组合以补偿经济变化，树木可能维持一系列外生菌根以应对不断变化的环境。本项目采用实验室实验和数学模型相结合的方法来检验代谢下注对冲假说。该研究结果将对花旗松的管理具有直接价值，花旗松是一种重要的商业林业树种，也是国外一些地区的侵略性入侵树种。本科生和高中生都将参与该项目，在科学方法方面接受宝贵的训练。

Many plants rely on mutually-beneficial interactions with below-ground fungi called mycorrhizae that gather nutrients, supply water, and defend against pests in exchange for energy provided by the plant. An individual plant may host dozens of different species of mycorrhizae simultaneously, including species that appear to be of little to no benefit, or may be harmful. This project proposes the idea of metabolic bet-hedging to account for the diverse array of mycorrhizae maintained by individual trees. Because trees experience marked seasonal and interannual environmental variation, their nutrient requirements also vary over time, potentially altering the relative value of each fungal partner. As human investors maintain a portfolio of stocks to compensate for economic variation, trees may maintain a range of ectomycorrhizae to respond to changing environments. This project tests the metabolic bet hedging hypothesis using a combination of laboratory experiments and mathematical models. Results from this study will be of direct value to the management of Douglas fir, the tree species targeted in this study, which is both a commercially important forestry species and an aggressive invader in some foreign locales. Both undergraduate and high school students will participate in the project, receiving valuable training in the scientific method.