从植物生理特点和形态适应性的角度分析气候环境对植物有机体稳定性碳同位素组成(?13C)的作用机理,是运用有机体?13C进行古气候定量重建的基础.C4植物粟(Setaria italica)和黍(Panicum miliaceum)是中国北方旱作农业的代表作物,其炭化种子易获取、可鉴定到种,?13C可靠性强,是古气候研究的潜在理想材料.通过采集黄土高原地区不同生境现代栽培粟、黍,分析其?13C与环境要素(包括纬度、海拔、全年和生长期的温度、降水量、水分有效性(P/Ep)、湿度等)的关系,结果显示粟?13C值仅与纬度(光照)具有显著负相关关系(相关系数R=?0.46),光照对粟?13C值的影响占21%,其他气候要素对粟?13C值未产生显著影响,粟?13C值不适用于提取气候因素信息;黍?13C与生长期降水量(Pgp)具有显著正相关关系(R=0.75),Pgp对黍?13C的影响程度达到56%.解析黍作物生理特性和形态调整的作用机制,显示在水分胁迫条件下黍植株对环境的适应性主要是通过气孔因素实现的,因此黍?13C能够较好地记录作物生长过程中降水量状况,在古气候定量重建方面具有一定的应用前景. The mechanism of climatic environment on the stability of carbon isotope composition (? 13C) of plant organisms from the perspective of plant physiological characteristics and morphological adaptability is the basis for the quantitative reconstruction of paleoclimate using organism? 13C. Panicum miliaceum, a representative crop of dry farming in northern China, has easy access to carbonized seeds and high reliability of 13C, which is a potential ideal material for palaeoclimate research. By collecting modern habitats from different habitats in the Loess Plateau, Millet and millet, the relationship between 13C and environmental factors (including latitude, altitude, annual and growing temperature, precipitation, water availability (P / Ep), humidity, etc.) was analyzed. And the latitude (light) had a significant negative correlation (correlation coefficient R =? 0.46), the impact of light on the 13C value of millet accounted for 21%, other climatic factors had no significant effect on millet 13C value, millet 13C value is not applicable There was a significant positive correlation between 13C and Pgp (R = 0.75), and Pgp had a 56% impact on 13C of millet.Analysis of the physiological characteristics and morphological adjustment of millet Mechanism, shown in water stress Under milking conditions, the adaptability of millet plants to the environment was mainly achieved by stomatal factors. Therefore, millet? 13C can record the precipitation during crop growth well and has certain application prospects in quantitative reconstruction of paleoclimate.