Ecosystem-level Consequences of Mutualist Partner Choice in Alder across a Forest Successional Sequence in Interior Alaska

阿拉斯加内陆森林演替序列中桤木互惠伙伴选择的生态系统层面后果

• 批准号: 0641033
• 负责人: Roger Ruess
• 金额: $ 79.62万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0641033&HistoricalAwards=false
• 关键词: Ecosystem; level; Consequences; Mutualist; Partner

Most nitrogen-fixing plants form mutualistic relationships between their roots and microorganisms in the soil. This involves the use of plant sugars to support bacteria that capture atmospheric nitrogen gas into the roots of the plant, as well as to support fungi that take up soil phosphorus and also move it into the roots. This study proposes that coordinated changes in host selection for both partners by the tree, red alder, enables persistence of this nitrogen-fixing species as interior Alaskan forests develop over time after disturbances such as fire, and regulates the overall nitrogen inputs to these forests. The identity and physiology of the bacterial and fungal partners will be measured over an age sequence of forest stands. Then shifts in the microbial partners in stands that have been fertilized will be documented and used to help design partner choices for a set of experiments in a greenhouse. Physiological consequences of these shifts for nitrogen as measured in the greenhouse will be scaled back to the ecosystem using measurements of the mass of root nodules in combination with seasonal patterns of measured nitrogen fixation. This project will be the first to study the influence of mutualist partner choice on nitrogen fixation inputs at the ecosystem scale. Understanding controls over nitrogen fixation by native and invasive plants is a problem of fundamental scientific value in Alaska, where invasive nitrogen fixing trees are beginning to appear, and where the range of alders has expanded substantially across the boreal/tundra boundary over the past 150 years. The project has strong ties to the Bonanza Creek Long-term Ecological Research program, where education and public outreach activities will include components of this study. This project will also result in the training of one post-doctoral fellow, two graduate students, and six undergraduates in state-of-the art field, molecular and bioinformatics methods.

大多数固氮植物在它们的根和土壤中的微生物之间形成互惠关系。这涉及使用植物糖来支持将大气中的氮气捕获到植物根部的细菌，以及支持吸收土壤磷并将其转移到根部的真菌。 这项研究提出，协调变化的主机选择的两个合作伙伴的树，红桤木，使持久性的这种固氮物种的内部阿拉斯加森林发展随着时间的推移后，如火灾的干扰，并调节这些森林的整体氮输入。 细菌和真菌伴侣的身份和生理学将在森林的年龄序列上进行测量。然后，已施肥的林分中微生物伴侣的变化将被记录下来，并用于帮助设计温室中一组实验的伴侣选择。 在温室中测量的氮的这些变化的生理后果将使用根瘤质量的测量结合测得的固氮的季节性模式按比例缩小到生态系统。 该项目将首次在生态系统尺度上研究互惠伙伴选择对固氮投入的影响。 了解本地和入侵植物的固氮控制是一个基本的科学价值在阿拉斯加，入侵固氮树开始出现的问题，并在那里的赤杨的范围已大大扩大在北方/苔原边界在过去的150年。该项目与Bonanza Creek长期生态研究计划有着密切的联系，教育和公共宣传活动将包括本研究的组成部分。 该项目还将培养一名博士后研究员、两名研究生和六名本科生，从事分子和生物信息学方法的最新领域的研究。