Does E. Vaginatum Take up Organic N?

标题：北极植物绒螯蟹是否吸收有机氮？查平等人。(1993)的研究表明，统治北极苔原的植物--绒螯蟹不仅可以利用有机氮源，而且作为唯一氮源的氨基酸实际上比无机氮盐生长得更好。这种转变的观点面临的一个挑战是，没有人真正量化在野外生长的任何植物物种，以及有多少阴道毛滴虫？S的总氮需求是由有机氮源满足的！该项目将量化其使用的N的形式，并评估其他几个冻土带群落的有机养分动态。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，从而测试正在开发的氮限制植物的有机营养理论。该项目将通过将新材料整合到加州大学圣巴巴拉大学的课堂上来支持本科教育，并为加州大学圣巴巴拉大学一年级的本科生和二年级的阿拉斯加学生提供研究经验，以帮助他们进行实地考察。它将与Toolik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，让公众参与到三个目标中：1.更好地欣赏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；3.更好地欣赏科学和科学家的工作和思考方式。回答“植物真的使用有机氮吗？”这个问题的挑战？一直是方法论上的。该项目将使用通过模拟建模集成的方法组合。最新的关键方法是微透析，将根大小的探针插入土壤中，载体溶液流过土壤，小分子扩散到土壤中。微渗析将与完整的根系吸收动力学研究、同位素分配和分析氨基酸、NH4和NO3-在土壤中的扩散和运输相结合，以参数化根系吸收模型，该模型将用于合成和整合结果。第一阶段的工作将在温室受控条件下进行；然后，在改进方法和评估模型参数后，这项研究将转移到田间，以评估氮素吸收的季节模式以及环境操纵对其的影响。

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.