中文摘要：

采用FTIR和1H NMR、13C NMR研究了蕹菜Ipomoea aquatica Forsk.低Cd品种（QLQ）和高Cd品种（T308）根际土壤水溶性有机质（dissolved organic matter,DOM）的结构特征。结果显示蕹菜两个品种根际土壤DOM均以碳水化合物为主要组成物质,烷基链烃和芳香族物质较少。两个品种根际土壤DOM的结构特征存在明显差异。QLQ根际土壤DOM中羧基C和长链脂肪C的相对含量较T308低,但芳香族物质含量较T308高,烷基链烃物质具有含量高、支链短、分支多的特征;QLQ根际土壤DOM中碳水化合物H含量较T308低,但碳水化合物C含量较T308高,显示碳水化合物结构可能存在品种间差异。推测QLQ根际土壤DOM的结构特征可能影响根际土壤Cd的行为与有效性,导致其对土壤Cd的活化能力较弱,这可能与其低Cd积累特性有关。

英文摘要：

Fourier transform infrared spectroscopy（ FTIR） and nuclear magnetic resonance spectroscopy（1H NMR and13 C NMR） were used to investigate the structural characteristics of dissolved organic matter（ DOM） in the rhizosphere soil of a low-Cd cultivar（ QLQ） and a high-Cd cultivar（ T308） of water spinach（ Ipomoea aquatica Forsk.）. The results showed that carbohydrates were the main components of DOM in the rhizosphere soil of the two cultivars,and the contents of alkyl and aromatic substances were relatively low. There were obvious differences in the structural characteristics of DOM between the two cultivars. The relative contents of carboxylic C and long-chain aliphatic C of DOM in the rhizosphere soil of QLQ were lower than those of T308,but that of aromatic substance of QLQ was higher. Alkyl sub-stance of DOM in the rhizosphere soil of QLQ possessed the characteristics of relatively high content,short branched chain and high branched chain. Although carbohydrate H content of DOM in the rhizosphere soil of QLQ was lower than that of T308,carbohydrate C content was higher than that of T308,which suggested that there might be differences in the structure of carbohydrates of DOM in the rhizosphere soil between the cultivars. The results indicated that the structural characteristics of DOM in the rhizosphere soil of the low-Cd cultivar might influence Cd behavior and bioavailability,leading to relatively low ability to activate soil Cd,which would be associated with its low Cd accumulation.