以我国部分代表性地区非盐性土壤中嗜盐和极端耐盐原核生物为研究对象，深入探讨非盐性土壤中该类微生物的多样性及其来源这个科学问题。在建立有效分离方法的基础上，应用纯培养法和基于DNA序列的系统发育分析法[16S rRNA基因序列分析和多位点序列分析（MLSA）],深入研究非盐性土壤中嗜盐和极端耐盐细菌（含放线菌）和古菌的类群多样性、物种多样性、遗传多样性和生理多样性，并分析其分布特点和可能来源；利用多相分类方法对代表潜在新类群的菌株进行分类学研究。可以较全面地认识该类微生物资源多样性的基本状况，了解其分布特点，初步探讨其多途径来源的可能性，对完善微生物生态学理论体系具有重要意义；建立一套非盐性土壤中嗜盐菌的有效分离方法，分离和保藏一批代表性菌株，确定部分潜在新类群的分类地位，为进一步研究其耐盐机理和进化模式提供模式菌株、并为利用或控制该类微生物资源提供理论指导。

To investigate the biodiversity, origin and taxonomy of halophilic and extremely halotolerant prokaryotes inhabiting ordinary non-saline soils by using conventional culture-dependent method. After developing an appropriate isolation approach based on the results of a research about the influence of various nutritional factors and growth conditions (salt concentration, temperature and pH value) on the numbers of colony forming unit and the bacterial diversity of the isolates, halophilic and extremely halotolerant prokaryotic strains, both Bacteria and Archaea, would be isolated from non-saline soil samples. Then, the biodiversity of the isolates, including physiological, genetic and species diversity and diversity of communities, would be investigated in detail on the basis of the results of physiological studies and phylogenetic analysis by using the 16S rRNA gene sequence comparing and the multilocus sequence analysis (MLSA) methods, respectively. The distribution and origin of the halophilic and extremely halotolerant prokaryotes inhabiting non-saline soil also would be analyzed based on the data both from this study and from references. Furthermore, some strains representing potential new taxa would be characterized in detail by using a polyphasic taxonomic approach, and then be formally described and validly published, which would be helpful in the conservation and utilization of these microbial resources. Consequently, i) the biodiversity of halophilic and extremely halotolerant prokaryotes inhabiting non-saline soil would be generally recognized, and the potential distribution rules and possible origination patterns of these organisms might be understood to a certain extent; ii) an appropriate isolation approach being used to isolate these microorganisms would be designed; iii) some typical strains would be isolated and then be deposited effectively so as to be used further as model organisms in the study on the mechanism of evolution and adaption of halophilic and extremely halotolerant prokaryotes in non-saline environments.