土壤矿物与微生物相互作用的机理及其环境效应

土壤矿物与微生物相互作用是地球表层系统中重要的生态过程.微生物或生物分子与矿物间的吸附(粘附)是两者相互作用的基础.吸附(粘附)是一个由分子间力、静电力、疏水作用力、氢键和空间位阻效应等多种作用力或作用因素共同决定、影响的物理化学过程.因此,微生物和矿物的表面性质如表面电荷、疏水性和它们所处的环境条件如pH、电解质浓度、温度等,都影响着矿物-微生物吸附(粘附)过程.微生物细胞或酶可吸附于矿物表面,其结果是细胞代谢或酶活性会发生明显变化,并进一步影响土壤中诸多相关的生态、环境过程.结合4种典型的初始吸附理论:表面自由能热力学理论、DLVO理论、吸附等温线理论和表面复合物理论及本课题组近年来的研究成果,对土壤矿物与微生物相互作用的类型、机理、作用力和现代研究技术等方面的最新研究进展进行了较为全面的论述,对土壤矿物-微生物相互作用的环境效应进行了讨论,并就该领域今后研究工作的特点及应关注的问题进行了展望.

Interaction mechanisms of soil minerals with microorganisms and their environmental significance

The interaction between mineral and microorganism is one of the most important ecological processes in soil system.The first step of microorganism-mineral interactions is the initial adhesion of microbes or biomolecules to soil minerals.As a physicochemical process,the initial adhesion was controlled by Lifshitz van der waals,electrostatic and hydrophobic forces,hydrogen bonding,as well as steric effect.The activities of microorganisms and extracellular biomolecules may subsequently be influenced after the attachments of microbial cells onto mineral surfaces.The effect of minerals on the activity of microorganisms or biomolecules may be positive,negative or neutral.This paper presents some recent advances on the interaction mechanisms of microbes with minerals especially the initial adhesion models such as surface free energy thermodynamics,DLVO theory,adsorption isotherms and surface complexation.The authors focus mainly on the interfacial and adhesion forces for the interaction between these inorganic and alive soil components.The environmental significances of these interactions are also discussed.Some modern molecular techniques such as atomic force microscopy(AFM),extended x-ray absorption fine structure(EXAFS) and microcalorimetry,which are powerful tools for probing biophysicochemical interactions between soil microorganisms and soil particles,are highlighted.A brief outlook is given on future studies that are needed in this intersect field.