Abundance and Adaptation Level of Some Soil Microbes in Salt-affected Soils

The abundance of some culturable soil microorganisms (bacteria and fungi) was examined at two Hungarian salt-affected soils of the Hortobagy region. In addition to the so-called “helper bacteria” ( Pseudomonas sp., nitrogen fixers), which are mainly attached to the rhizoplane, the abundance of other microbial groups (total number of bacteria, micromycetes, Actinomycetes ) were also assessed. A modified, selective plate dilution assay was used with increasing salt (NaCl) concentrations (5-50 g l -1 media), for assessing the salt tolerant ratio of specific microbial groups.    The type of main salt-specific ions differed at the two sites, resulting more or less stressed pH conditions in the rhizosphere of the most typical halophytes. At Zam mainly the chloride, at Nyirőlapos, however mainly sulphate ions dominated in the samples (at an 80% level), which resulted in a more severe stress situation. Actinomycetes proved to be especially abundant in the salt affected soils examined. In almost all microbial grou...