Does E. Vaginatum Take up Organic N?

题目：北极植物Eriophorum vaginatum吸收有机氮吗？Chapin et al.（1993）研究表明，在北极tussock苔原上占主导地位的植物Eriophorum vaginatum不仅可以利用有机N源，而且实际上氨基酸作为唯一N源比无机N盐生长得更好。这种转变观点的一个挑战是，没有人真正量化，对于任何在野外生长的植物物种，阴道芽孢杆菌的数量是多少？中国的总氮需求由有机氮源满足！这个项目将量化它所使用的氮的形式，并评估其他几个苔原群落的有机营养动态。更广泛地说，该项目将开发更多的方法来评估其他生态系统类型的有机营养，从而测试发展中的氮素限制植物有机营养理论。该项目将通过将新材料整合到加州大学圣巴巴拉分校的课程中来支持本科教育，并为加州大学圣巴巴拉分校一年级的本科生和一名阿拉斯加学生提供研究经验，以帮助二年级的野外季节。它将与工具长期生态系统研究教育项目合作，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，吸引公众参与，以实现三个目标：更好地认识土壤在我们的生活和生态系统中的作用；2 .了解北极是地球系统的一个组成部分；为了更好地理解科学和科学家是如何工作和思考的。回答“植物真的利用有机氮吗？”这个问题的挑战一直是方法论上的。本项目将通过仿真建模综合使用多种方法。关键的新方法是微透析，将根大小的探针插入土壤，载体溶液流过，小分子扩散到土壤中。微透析将与完整的根系吸收动力学研究、同位素分配以及氨基酸、NH4+和NO3-在土壤中的扩散和运输分析相结合，以参数化根系吸收模型，用于综合和整合结果。第一阶段的工作将在温室的受控条件下进行；然后，在改进方法和评估模型参数之后，该研究将进入实地，以评估氮吸收的季节性模式以及它如何受到环境操纵的影响。

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.