Does E. Vaginatum Take up Organic N?

北极植物羊胡子草吸收有机氮吗？Chapin等人（1993年）表明，在北极草丛冻原中占主导地位的植物物种羊胡子草（Eriophorum vaginatum）不仅可以利用有机氮源，而且实际上以氨基酸作为唯一氮源比无机氮盐生长得更好。这种观点转变的一个挑战是，没有人真正量化过，对于任何生长在野外的植物物种，有多少E。阴道？的总N需求是由有机N源满足的！该项目将量化其使用的N的形式，以及评估其他几个苔原社区的有机营养动态。更广泛地说，该项目将开发在其他生态系统类型中更多地评估有机营养的方法，从而测试正在发展的氮限制植物有机营养理论。该项目将通过将新材料融入加州圣巴巴拉大学的课程来支持本科生教育，并通过在第一年为加州圣巴巴拉大学的本科生提供研究经验，以及在第二年为阿拉斯加学生提供野外季节的帮助。它将与图里克长期生态系统研究教育计划协调，创建一个关于“植物吃什么”的模块。“参与者将与圣巴巴拉自然历史博物馆合作，开发一系列活动，吸引公众实现三个目标：1。更好地理解土壤在我们的生活和生态系统中的作用，2。了解北极作为地球系统的一个组成部分，和3。为了更好地理解科学和科学家是如何工作和思考的，回答“植物真的使用有机氮吗？“方法论。该项目将使用通过模拟建模集成的方法组合。关键的新方法是微透析，在这种方法中，将根大小的探针插入土壤中，载体溶液流过它，小分子扩散到其中。微透析将与完整根吸收动力学研究，同位素分配以及分析氨基酸的扩散和运输相结合，NH 4+和NO3-通过土壤参数化的根系吸收模型，将用于综合和整合的结果。第一阶段的工作将在温室内的受控条件下进行;然后在改进方法和评估模型参数后，研究将转移到实地，以评估氮吸收的季节模式以及环境操作如何影响氮吸收。

TITLE: Does the Arctic plant Eriophorum vaginatum take up organic N?Chapin et al. (1993) showed that Eriophorum vaginatum, the plant species that dominates arctic tussock tundra, not only can use organic N-sources, but actually grows better with amino acids as a sole N-source than with inorganic N salts. A challenge of this shifting view is that no one has actually quantified, for any plant species growing in the wild, and how much of E. vaginatum?s total N demand is met by organic N-sources! This project would quantify the forms of N it uses, as well as assessing organic nutrient dynamics in several other tundra communities. More broadly, this project would develop approaches for assessing organic nutrition more in other ecosystem types and so test the developing organic nutrition theory of N-limited plants. This project will support undergraduate education by integrating new material into classes at University California Santa Barbara, and by offering research experiences to a University California Santa Barbara undergraduate during year-1 and an Alaskan student to help with the field season in year-2. It will coordinate with the Toolik Long Term Ecosystem Research education program in creating a module on "What Plants Eat." The participants will work with the Santa Barbara Natural History Museum to develop a suite of activities that will engage the public to target three goals: 1. A better appreciation of the role of soil in our lives and ecosystems, 2. To understand the Arctic as a component of the Earth System, and 3. To better appreciate how science and scientists work and think.The challenge to answering the question "Do plants really use organic N?" has been methodological. This project would use a combination of methods integrated through simulation modeling. The key novel method is microdialysis, in which a probe the size of a root is inserted into the soil, a carrier solution flows through it, and small molecules diffuse into it. Microdialysis will be coupled with intact root uptake kinetic studies, isotope partitioning, and analyzing diffusion and transport of amino acids, NH4+ and NO3- through soil to parameterize a root uptake model that will be used to synthesize and integrate the results. The first phase of the work will be done under controlled conditions in the greenhouse; then having refined the methods and assessed model parameters, the study will be moved into the field to assess seasonal patterns of N uptake and how it is affected by environmental manipulations.