中文摘要：

以豫中平原地热水补给区裸露地表处广泛种植的毛白杨（Populus tomentosa）落叶提取的DOM为研究对象,首先确定了对DOM提取的的最佳时间,然后通过对DOM的紫外-可见光谱和三维荧光光谱的测定及对SUVA（254）、A（253）/A（203）、A（250）/A（365）、r（A/C）等参数的计算,对DOM中的有机物结构和类型进行了研究。研究结果表明：毛白杨落叶DOM浸提的最佳振荡时间为24 h,DOC和UV（254）具有较高的线性相关关系,说明毛白杨落叶DOM中有较多的含苯环的简单芳香族化合物,并且芳香环取代基中含有较多的羰基、羧基、羟基、脂类。DOM中存在有4类荧光峰,荧光强度由大到小的顺序依次为类腐殖质峰（包括紫外区类富里酸峰（A峰）和腐殖酸类物质峰（C峰））、酪氨酸类芳香族蛋白峰T、溶解性微生物代谢产物峰B。在DOM样品不同的稀释倍数条件下,所反映的有荧光特性的溶解性有机物的结构和相对含量有所变化,这与DOM样品的pH变化、复杂的成分种类、混合荧光信号的存在等因素有关。

英文摘要：

To study the structure and type of dissolved organic matter extracted from the fallen leaves of Populus tomentosa,which are widely grown in the geothermal water recharge area in the plain of East Henan,experiments were carried out firstly to determine the optical time of extracting dissolved organic matter（DOM） from the fallen leaves of Populus tomentosa.Then the UV-Vis and three-dimensional fluorescence spectrum of DOM were measured,after which the parameters of SUVA（254）,A（253）/A（203）,A（250）/A（365） and r（A/C） were calculated.The results showed that it is better to extract DOM from the fallen leaves of Populus tomentosa after oscillating for 24 h.DOC is highly linearly correlated with UV（254）indicated by the regression coefficient（R^2=0.92） for the studied DOM sample,suggesting that many simple aromatic compounds containing benzene ring exist in the studied DOM and many kinds of aromatic ring substituents contain carbonyl,carboxyl,hydroxyl and lipids.Totally 4 types of fluorescence peak appear in the studied DOM,and the fluorescence intensity in the descending order are humic-like peak（including fulvic-like peak A and humic substances peak C in ultraviolet region）,tyrosine aromatic protein peak T and soluble microbial metabolites peak B.At different dilution conditions of DOM samples,the validated structure and relative content of dissolved organic matter with fluorescent properties are slightly different,which are related with the factors such as the pH change of DOM samples,complex composition and disturbance of mixed fluorescent signal.