ИСТИНА

The spruce and birch mycorrhizosphere impact on soil micromycetes and bacterial numbers versus rhizosphere and hyphosphere effects was studied under natural conditions. The soil free from roots and basidiomycete mycelia was taken as a control. Increase in microorganisms numbers was detected in all rhizosphere samples versus control and no difference between tree species was revealed. The most common mycorrhizosphere impact on bacteria was significant increase versus either control or rhizosphere soil. The impact on micromycetes was more various and consisted in some cases in increase or decrease compared to control soil. Microorganism numbers were higher in birch mycorrhizosphere compared to spruce but the difference wasn`t always statistically significant. Hyphosphere and mycorrhizosphere effects varied strongly in colonies of different basidiomycete species even belonging to the same genus. The decrease of fungal and increase of bacterial numbers was usual pattern for hyphosphere and mycorrhizosphere of majority of studied symbiotrophic species.