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| Large area two dimensional mapping of carbon dioxide fluxes for assessment and control of carbon capture and storage project | |
| 项目编号 | ST/L00626X/1 |
| David Jones | |
| 项目主持机构 | NERC British Geological Survey |
| 开始日期 | 2014-06-25 |
| 结束日期 | 2017-03-31 |
| 英文摘要 | Nitrogen is the mineral element that plants require in greatest amounts. A major source of nitrogen for plants is the nitrate that they absorb from soils. Research in the Bloom laboratory has established that rising CO2 (carbon dioxide) concentration in Earth's atmosphere inhibits the conversion of nitrate into proteins in the shoots of most plant species. One physiological mechanism responsible for this phenomenon involves photorespiration, a process through which sugars in a plant react with oxygen instead of CO2. Photorespiration has been erroneously portrayed as a wasteful process, but in fact, photorespiration generates energy necessary for converting nitrate into protein. Elevated CO2 decreases photorespiration, which leads to declines in plant protein concentrations, slower plant growth, and lower food value. The proposed research will examine how photorespiration transfers energy to convert nitrate into protein. It will examine the chemical structure of the enzymes that facilitate these reactions and to trace the flows of energy from one reaction to another. This information will provide a new perspective on the efficiency of photosynthesis and greater insight on the influence that rising CO2 will have on the distribution of plant species. Rising CO2 concentration in the atmosphere inhibits NO3 assimilation into proteins in the shoots of C3 plants and impedes their growth when NO3 is the predominant N source. One process that links CO2 concentration to shoot NO3 assimilation is photorespiration. Photorespiration stimulates the export of malic acid from chloroplasts and increases the availability of NADH in the cytoplasm that empowers the reduction of NO3 to NO2, the first step of NO3 assimilation. CO2 enrichment decreases photorespiration, decreasing the amount of NADH available for NO3 reduction. The proposed research will examine this mechanism in greater detail. Nearly all studies of Rubisco are conducted in the presence of magnesium, which favors carboxylation, rather than in the presence of manganese, which favors oxygenation and electron transfers that might stimulate NADP+ reduction. The objectives of this research are: 1) use X-ray crystallography to confirm the locations of manganese and NADP+ within tobacco Rubisco, 2) identify via electron paramagnetic resonance (EPR) the structural changes of transient enzyme-substrate complexes and catalytic reaction intermediates during photorespiration, and 3) conduct site-directed mutagenesis of residues in the catalytic large subunit of Rubisco that are involved with photorespiratory electron transfer to provide powerful structural probes. Energy transfers between photorespiration and nitrate assimilation should explain why over 95% of higher plant species still rely solely on C3 fixation even after more than 20 million years of relatively low atmospheric CO2 concentrations and multiple introductions of the C4 pathway: C3 fixation is more efficient than previously thought because photorespiration supports nitrate assimilation. Moreover, these mechanisms should explain why plant responses to elevated CO2 are highly variable: in C3 plants that are dependent on nitrate, CO2 inhibition of shoot nitrate assimilation causes organic N deficiencies and slows growth, whereas in C3 plants dependent on ammonium, elevated CO2 promotes growth. |
| 学科分类 | 03 - 天文学;04 - 物理学;0407 - 粒子物理学和场论;0408 - 核物理;0409 - 核技术及其应用;0410 - 粒子物理与核物理实验方法与技术 |
| 资助机构 | UK-STFC |
| 项目经费 | 19536 |
| 项目类型 | Research Grant |
| URL | http://gtr.rcuk.ac.uk:80/projects?ref=ST/L00626X/1 |
| 国家 | UK |
| 语种 | 英语 |
| 文献类型 | 项目 |
| 条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/74619 |
| 推荐引用方式 GB/T 7714 | David Jones.Large area two dimensional mapping of carbon dioxide fluxes for assessment and control of carbon capture and storage project.2014. |
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