Do Internal N Signals Regulate Interspecific Variability in N Uptake Response to Elevated CO?

内部氮信号是否调节氮吸收对 CO 升高的反应的种间变异？

• 批准号: 0213066
• 负责人: Hormoz BassiriRad
• 金额: $ 25万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-15 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0213066&HistoricalAwards=false
• 关键词: Do; Internal; Signals; Regulate; Interspecific

While there is a general consensus among scientists that the projected rise in the concentration of atmospheric CO2 will have a profound impact on productivity and composition of terrestrial ecosystems, our capacity to reliably predict the exact nature of these changes remain tenuous. The unknown effects of other environmental factors such as nitrogen (N) and water are major sources of this uncertainty. N is an essential mineral nutrient whose availability and utilization regulates plant responses to high CO2. This high leverage by N is fortuitous when one considers the intricate connection between carbon (C) and N in plant biology. It is well recognized that in the short term, plants exposed to high CO2 will enhance their C uptake. Theoretically, however, only those species that can maintain a balance between N and C demand will sustain a long-term positive effect. The few available data indicate that plant species vary widely in their N uptake responses to high CO2. However, observations from a few empirical studies can not be extrapolated to cover a wide range of species around the globe and we currently lack a mechanistic understanding to develop such a roadmap. Here we propose to elucidate the major mechanism(s) that control plant N uptake when CO2 concentration is elevated using species from contrasting ecosystems. We propose to develop physiological and biochemical markers that could be used to gauge the extent to which a target species can maintain its N and C balance. The physiological and biochemical markers targeted here are known to control plant N uptake under natural conditions and therefore are likely to control N uptake responses under high CO2 as well. The findings are equally important for basic research and management/policy issues that must deal with increasing pressure to cope with the future climate. The proposed research will be conducted at six nationally funded Free Air Carbon dioxide Enrichment (FACE) experiments, two CO2 natural springs in Italy and New Zealand, and a number of open-top chambers at the University of Illinois at Chicago. The results generated here will be critical for the development of predictive models designed to forecast the fate of terrestrial ecosystems in a future climate.

尽管科学家们普遍认为大气二氧化碳浓度的预计上升将对陆地生态系统的生产力和组成产生深远影响，但我们可靠预测这些变化的确切性质的能力仍然很薄弱。其他环境因素（例如氮 (N) 和水）的未知影响是这种不确定性的主要来源。氮是一种必需的矿物质营养素，其可用性和利用率调节植物对高二氧化碳的反应。考虑到植物生物学中碳 (C) 和氮之间的复杂联系，氮的这种高杠杆作用是偶然的。人们普遍认识到，在短期内，暴露于高二氧化碳的植物将增强其碳吸收。然而，从理论上讲，只有那些能够保持氮和碳需求平衡的物种才能维持长期的积极影响。少数可用数据表明，植物物种对高二氧化碳的氮吸收反应差异很大。然而，一些实证研究的观察结果无法推断以涵盖全球范围内的广泛物种，而且我们目前缺乏制定这样的路线图的机制理解。在这里，我们建议使用来自对比生态系统的物种来阐明当二氧化碳浓度升高时控制植物氮吸收的主要机制。我们建议开发生理和生化标记，可用于衡量目标物种维持氮和碳平衡的程度。众所周知，这里针对的生理和生化标记可以控制自然条件下植物的氮吸收，因此也可能控制高二氧化碳下的氮吸收反应。这些发现对于必须应对日益增加的压力以应对未来气候的基础研究和管理/政策问题同样重要。拟议的研究将在六个国家资助的自由空气二氧化碳富集（FACE）实验、意大利和新西兰的两个二氧化碳天然泉水以及伊利诺伊大学芝加哥分校的多个开顶室中进行。这里产生的结果对于开发旨在预测未来气候下陆地生态系统命运的预测模型至关重要。