The effect of mineral and organic fertilization on the occurrence of soil microorganisms was determined in a field experiment. The colony-forming unit counts of saprotrophic microfungi, when estimated on a silicate gel medium containing fulvic acid as a sole carbon source, increased significantly with increasing doses of mineral and organic fertilization. Partial correlation analysis indicated that, unlike bacteria and actinomycetes, microfungi utilizing fulvic acid were significantly associated with soil organic carbon. No significant effects on bacteria and microfungi counted on common microbiological media were observed but counts of actinomycetes increased in a manured soil extensively fertilized by a mineral fertilizer. Fulvic acid utilizing microfungi, which are associated with areas rich in organics, play possibly the main role in mineralization of resistant forms of soil organic matter.

• MeSH
• Actinomyces izolace a purifikace   metabolismus   MeSH
• Bacteria izolace a purifikace   metabolismus   MeSH
• benzopyrany metabolismus   MeSH
• biodegradace MeSH
• houby izolace a purifikace   metabolismus   MeSH
• mikrobiologické techniky MeSH
• minerály MeSH
• organické látky metabolismus   MeSH
• počet mikrobiálních kolonií MeSH
• průmyslová hnojiva * MeSH
• půda analýza   MeSH
• půdní mikrobiologie * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• benzopyrany MeSH
• fulvic acid MeSH Prohlížeč
• minerály MeSH
• organické látky MeSH
• průmyslová hnojiva * MeSH
• půda MeSH

The effect of fulvic acids (FA) on arbuscular mycorrhizal (AM) fungi and on the toxicity of lead and manganese toward these symbionts were demonstrated in vitro. Incubation of root segments colonized with the AM fungus Glomus intraradices in undiluted fraction of FA (813 mg/L carbon) decreased an outgrowth of intraradical hyphae. Diluted FA solutions (< 271 mg/L C) did not influence the proportion of root segments bearing proliferating hyphae; solution containing 27.1 mg/L C even increased the proliferation. A decrease of heavy metal toxicity toward the fungus was observed when FA (81.3 mg/L C) were added to the solutions containing higher concentrations (< or = 100 mumol/L) of Mn and Pb; the positive effect of FA was not significant at higher concentrations of metals (0.5 mmol/L). A short-term cultivation of six different saprophytic microorganisms--three actinomycetes and three filamentous fungi--on the FA media (81.3 mg/L C) did not result in a modification of hyphal proliferation from the root segments subsequently incubated in these media.

• MeSH
• benzopyrany farmakologie   MeSH
• houby účinky léků   růst a vývoj   MeSH
• kořeny rostlin mikrobiologie   MeSH
• kultivační média MeSH
• mangan farmakologie   MeSH
• mykorhiza účinky léků   růst a vývoj   MeSH
• olovo toxicita   MeSH
• symbióza MeSH
• těžké kovy toxicita   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• benzopyrany MeSH
• fulvic acid MeSH Prohlížeč
• kultivační média MeSH
• mangan MeSH
• olovo MeSH
• těžké kovy MeSH

Mineralization of native organic matter and U-14C-glucose was followed by measuring the formation of CO2 and its radioactivity in chernozem soil presterilized by gamma-radiation and inoculated with a washed suspension of Cellulomonas sp. cells. The introduced bacteria mineralized the soil organic component to a higher extent in variants enriched with glucose. This so-called priming effect of glucose was observed also in the presence of chloramphenicol, inhibiting the growth of the bacteria. The increased mineralization of the native soil organic fraction was also detected in samples that were not enriched with glucose when the bacterial suspension was first disintegrated ultrasonically and the material then used for the inoculation. Possible participation of phenomena of the type of cometabolism and activation of cell membrane transport mechanisms on the occurrence of the priming effect of glucose in the soil is discussed.

• MeSH
• Actinomycetales účinky léků   růst a vývoj   metabolismus   MeSH
• chemická deprese MeSH
• chloramfenikol farmakologie   MeSH
• glukosa farmakologie   MeSH
• kultivační techniky MeSH
• oxid uhličitý biosyntéza   MeSH
• průmyslová hnojiva MeSH
• půdní mikrobiologie * MeSH
• sterilizace MeSH
• záření gama MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chloramfenikol MeSH
• glukosa MeSH
• oxid uhličitý MeSH
• průmyslová hnojiva MeSH

In chernozem soil, enriched with preparations of AS-lignin or lignofulvonic acid, an increased production of carbon dioxide was observed during a 4-week incubation, and, as compared with the non-amended control, an increased number of bacteria but not of actinomycetes was detected. Increased numbers of fungi were detected only in the variant with AS-lignin at the end of the incubation. The relative incidence of bacteria utilizing vanillin, syringic acid or protocatechuic acid as the only carbon sources increased in the enriched medium. Oxidation of vanillic acid, syringic acid and to a lesser extent of coumarin increased in suspensions of soils incubated with AS-lignin or fulvic acid. The results obtained indicate that bacteria are involved in the mineralization of the added substrates and confirm the relationship between metabolism of these compounds and simple aromatic derivatives.

• MeSH
• Actinomycetaceae růst a vývoj   MeSH
• Bacteria růst a vývoj   MeSH
• benzopyrany farmakologie   MeSH
• houby růst a vývoj   MeSH
• lignin farmakologie   MeSH
• oxid uhličitý analýza   MeSH
• půda analýza   MeSH
• půdní mikrobiologie * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• benzopyrany MeSH
• lignin MeSH
• oxid uhličitý MeSH
• půda MeSH