Quantification of Organic Nitrogen use in FACE and Culture Experiments

大部分植物氮素供应，特别是对树木的氮素供应，是由共生(菌根)真菌提供的，这些真菌从寄主树木获得糖，并反过来转移氮素。然而，方法上的困难限制了对菌根真菌在满足植物氮素需求方面所起作用的量化。在这个项目中，来自杜克大学和威斯康星州莱茵兰德的两个田间实验的碳和氮同位素比率将被用来评估不同菌根真菌和植物对有机氮的吸收。这些信息将与对菌根植物的实验室研究相结合，以提供对有机氮使用的第一个现实的和定量的估计。为该项目开发的新方法将确定不同生态系统和不同种类的菌根真菌对有机氮的使用模式是否不同。这项工作将开发和完善量化植物和菌根真菌对有机氮的使用的新方法，这将改变研究人员对土壤中氮素循环及其与土壤碳的联系的看法。这对森林管理有影响。教育工作将涉及与当地几名高中教师合作，扩大他们对户外教室的使用，并将真菌作为教授生物的工具。面向公众的活动还将包括教育阿巴拉契亚山地俱乐部(AMC)博物学家了解森林中真菌的作用，以及领导AMC自然徒步旅行。该项目将包括对一名博士生和几名本科生的培训，包括从伊丽莎白城州立大学招收学生，该大学是一所历史上的黑人学校，与北卡罗来纳大学有着密切的学术联系。

Much of plant nitrogen supply, particularly for trees, is supplied through symbiotic (mycorrhizal) fungi that obtain sugars from their host trees and in return transfer nitrogen. However, methodological difficulties have limited quantification of the role that mycorrhizal fungi play in meeting plant nitrogen demands. In this project, ratios of carbon and nitrogen isotopes from two field experiments at Duke University and at Rhinelander, Wisconsin will be used to assess organic nitrogen uptake by different mycorrhizal fungi and plants. This information will be combined with laboratory studies on mycorrhizal plants to provide the first realistic and quantitative estimates of organic nitrogen use. New methodologies being developed for this project will determine whether patterns of organic nitrogen use differ across ecosystems and across species of mycorrhizal fungi.This work will develop and perfect new methods to quantify organic nitrogen use by plants and mycorrhizal fungi which will transform how researchers think about nitrogen cycling in the soil and its connections to soil carbon. This has implications for forest management. Educational work will involve collaboration with several local high school teachers to expand their use of outdoor classrooms and use of fungi as a tool to teach biology. Outreach to the public will also include educating Appalachian Mountain Club (AMC) naturalists on fungal roles in forests as well as leading AMC nature walks. The project will involve training for a Ph.D. student and several undergraduates, including recruitment of students from Elizabeth City State University, a historically black institution with strong academic ties to UNH.