中文摘要：

采用平衡法研究了含有机质粗粘粒、去有机质粗粘粒、含有机质细粘粒和去有机质细粘粒4种红壤胶粒对DNA的吸附特征及其热力学特性.结果表明：4种红壤胶粒对DNA的吸附是快反应过程,Langmuir吸附方程可较好地描述4种红壤胶体对DNA的等温吸附,相应拟合的相关系数r2分别为0.974、0.991、0.958和0.975.最大吸附量表现为含有机质细粘粒〉去有机质细粘粒〉含有机质粗粘粒〉去有机质粗粘粒.电解质浓度和种类及吸附体系pH是影响红壤胶体对DNA吸附的重要因子,一定电解质浓度范围（NaCl〈60mmol·L-1,CaCl2〈10mmol·L-1）内,DNA在红壤胶体表面的吸附量随电解质浓度的增大而显著增加,其中钙离子的促进作用大于钠离子,但随着吸附体系pH的上升而显著降低.含有机质胶粒对DNA的吸附过程是吸热反应,而去有机质胶粒对DNA的吸附过程是放热反应,红壤胶粒对DNA的吸附反应过程是一个熵增过程.

英文摘要：

By using balance reaction method, this paper studied the adsorption characteristics and thermodynamic properties of DNA on four kinds of red soil colloids （ organic matter-contained coarse clay, organic matter-removed coarse clay, organic matter-contained fine clay, and organic matter- removed fine clay）. The DNA adsorption on the four red soil colloids was a process of fast reaction, and the adsorption isotherms were conformed to the Langmuir equation, with the corresponding cor- relation coefficient （ r^2） being 0. 974, 0. 991,0. 958, and 0. 975, respectively. The maximum ad- sorption amount of DNA on the colloidal particles followed the order of organic matter-contained fine clay 〉 organic matter-removed fine clay 〉 organic matter-contained coarse clay 〉 organic matter-re- moved coarse clay, implying that the size and organic matter content of colloidal particles played an important role in DNA adsorption. Electrolyte concentration and type and adsorption system pH were the main factors affecting the DNA adsorption on the four soil colloids. Within a definite elec- trolyte concentration range （NaC1 〈 60 mmol . L-1 and CaCl2 〈 10 mmol. L-1） , the adsorption amount of DNA on the red soil colloids increased significantly with the increase of electrolyte con- centration. As compared with sodium ion, calcium ion had a greater promotion effect on the DNA adsorption, but the effect decreased significantly with the increase of adsorption system pH. The DNA adsorption on the organic matter-contained red soil colloids was an endothermic reaction, while the DNA adsorption on the organic matter-removed red soil colloids was an exothermic reac- tion. The DNA adsorption on the red soil colloids was a process of entropy increase.