GRGC: Leaf Stomatal Density and Carbon Isotope Responses to CO2 Variations During the Past 40,000 Years

GRGC：过去 4 万年叶片气孔密度和碳同位素对 CO2 变化的响应

• 批准号: 9418269
• 负责人: Steven Leavitt
• 金额: $ 18.81万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-12-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9418269&HistoricalAwards=false
• 关键词: GRGC; Leaf; Stomatal; Density; Carbon

9418269 Leavitt This research is based on the assumption that changes in atmospheric CO2 concentrations over the past 40,000 years can be quantitatively measured by determining the stomatal density and stable-carbon isotope composition of modern and ancient plant leaves, particularly leaves preserved in packrat middens in the western U.S. To overcome the problem of separate effects of climate and CO2, PI intends to employ analog approach by using leaves from different latitudes and/or elevations to maintain constant climate. Samples from the same latitude but different ages and elevations will allow determination of whether attitudinal gradients in stomatal density and carbon isotopes are the same in high and low CO2 periods. Ground truthing will be through analysis of modern living samples and herbarium samples. Possible implications of the research include determination of the relative effects of CO2 concentrations and climate influences on vegetation change, refinement of carbon cycle and hydrological models during deglaciation, confirmation of CO2 and carbon isotope shifts identified in earlier studies, and enhanced understanding of CO2 variations in the evolution and distribution of C4 plant.

9418269 Leavitt这项研究基于这样一个假设，即通过测定现代和古代植物叶片的气孔密度和稳定碳同位素组成，可以定量测量过去4万年大气二氧化碳浓度的变化，特别是在美国西部的包鼠丘中保存的叶片。PI打算采用模拟方法，使用来自不同纬度和/或海拔的树叶来维持恒定的气候。来自同一纬度但不同年龄和海拔的样品将有助于确定气孔密度和碳同位素的态度梯度在高CO2期和低CO2期是否相同。地面真相将通过分析现代生物样本和植物标本室样本。该研究可能产生的影响包括确定CO2浓度和气候对植被变化的相对影响，改进消冰期间的碳循环和水文模型，确认早期研究中确定的CO2和碳同位素变化，以及加强对C4植物进化和分布中CO2变化的理解。