Cross-Site: Collaborative Research: Mycorrhizal Responses to Nitrogen Eutrophication at Five Mesic and Semi-Arid Sites

跨站点：合作研究：五个中干旱和半干旱地区菌根对氮富营养化的反应

• 批准号: 9527317
• 负责人: Nancy Johnson
• 金额: $ 10.85万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-02-01 至 1999-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9527317&HistoricalAwards=false
• 关键词: Cross; Site; Collaborative; Research; Mycorrhizal

9527317 Johnson Although nitrogen is frequently the most limiting nutrient in ecosystems, continuous, elevated inputs of nitrogen may cause significant ecosystem stress. Deposition of anthropogenic nitrogen has been associated with recent losses of plant as well as fungal diversity throughout Europe. Little is known about the effects of atmospheric nitrogen deposition on the structure and function of North American grasslands and shrublands, although as much as 30 kg nitrogen per hectare per year is deposited in southern California, with lesser amounts elsewhere in the US. The three principal objectives of this research will be to (1) assess species composition changes of fungi during nitrogen eutrophication in mesic to semiarid grasslands using microscopy and immunoflourescence, (2) assess the kinds of mycorrhizal fungi under nitrogen eutrophication to indicate the mutualistic or parasitic effects of fungi, and (3) conduct bioassays to determine whether inferior mutualists predominate after nitrogen eutrophication. This study will examine the effects of nitrogen eutrophication on mycorrhizae at four experimental grasslands within the Long-term Ecological Research network and at a shrub-grasslands in southern California. These grasslands in Michigan, Minnesota, Kansas, New Mexico, and California form a precipitation and fertility gradient. The effects of nitrogen euthrophication will be studied on plants, mycorrhizal fungi and soils in experiments that have previously been established and in new plots at these sites. This research is designed to assess the ranges and variances of mycorrhizal responses to nitrogen at three scales: at individual plant-root interfaces, within grasslands communities, and across a climatic and soil gradient. This is a first step toward assessing the potential effects of nitrogen eutrophication on the structure and functioning of mycorrhizae-plant interactions in grasslands in the US. This research is important because grasslands are the basis for rang e resources and beef production in North America.

9527317约翰逊虽然氮通常是生态系统中最有限的养分，但氮的连续，升高的氮输入可能会引起重大的生态系统胁迫。 人为氮的沉积与近期植物损失以及整个欧洲的真菌多样性有关。 关于大气氮沉积对北美草原和灌木丛的结构和功能的影响知之甚少，尽管每年每年沉积多达30 kg氮，在南加州，在美国其他地方较少。 The three principal objectives of this research will be to (1) assess species composition changes of fungi during nitrogen eutrophication in mesic to semiarid grasslands using microscopy and immunoflourescence, (2) assess the kinds of mycorrhizal fungi under nitrogen eutrophication to indicate the mutualistic or parasitic effects of fungi, and (3) conduct bioassays to determine whether inferior共同主义者在氮富营养化后占主导地位。 这项研究将检查氮气对长期生态研究网络中四个实验草原和南加州的灌木丛地群落中的四个实验草原上的菌根的影响。 这些草原在密歇根州，明尼苏达州，堪萨斯州，新墨西哥州和加利福尼亚州形成降水和生育梯度。 将在以前已确定的实验中并在这些地点的新图中研究氮，菌根真菌和土壤的氮气的影响。 这项研究旨在评估三个尺度上对氮的菌根反应的范围和方差：在各个植物根界面，草原社区内以及气候和土壤梯度上。 这是评估氮富营养化对美国草原菌根植物相互作用的结构和功能的潜在影响的第一步。 这项研究很重要，因为草原是北美地区资源和牛肉生产的基础。