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

许多植物依赖于与被称为菌根的地下真菌的互利互动，菌根收集营养、供应水分和抵御害虫，以换取植物提供的能量。一株植物可能会同时寄生数十种不同的菌根，包括那些似乎几乎没有益处或可能有害的种类。该项目提出了新陈代谢对冲的想法，以说明由个别树木维持的菌根的多样性阵列。由于树木经历了显著的季节性和年际环境变化，它们的营养需求也随着时间的推移而变化，潜在地改变了每个真菌伙伴的相对价值。随着人类投资者维持股票投资组合以补偿经济变化，树木可能会维持一系列外生菌根以应对不断变化的环境。该项目使用实验室实验和数学模型相结合的方法来检验新陈代谢押注对冲假说。本研究的结果将对本研究的目标树种道格拉斯冷杉的管理具有直接的价值，道格拉斯冷杉既是一种重要的商业林业树种，也是一些外来地区的侵略性入侵物种。本科生和高中生都将参与该项目，接受宝贵的科学方法培训。

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.