Effects of long-term mineral fertilization and manuring on the biomass of arbuscular mycorrhizal fungi (AMF) were studied in a field experiment. Mineral fertilization reduced the growth of AMF, as estimated using both measurements of hyphal length and the signature fatty acid 16:1omega5, whereas manuring alone increased the growth of AMF. The results of AMF root colonization followed the same pattern as AMF hyphal length in soil samples, but not AMF spore densities, which increased with increasing mineral and organic fertilization. AMF spore counts and concentration of 16:1omega5 in soil did not correlate positively, suggesting that a significant portion of spores found in soil samples was dead. AMF hyphal length was not correlated with whole cell fatty acid (WCFA) 18:2omega6,9 levels, a biomarker of saprotrophic fungi, indicating that visual measurements of the AMF mycelium were not distorted by erroneous involvement of hyphae of saprotrophs. Our observations indicate that the measurement of WCFAs in soil is a useful research tool for providing information in the characterization of soil microflora.

• MeSH
• biologické markery analýza   MeSH
• hnůj MeSH
• hyfy růst a vývoj   MeSH
• mastné kyseliny analýza   MeSH
• Medicago sativa mikrobiologie   MeSH
• minerály MeSH
• mycelium růst a vývoj   MeSH
• mykorhiza růst a vývoj   MeSH
• počet mikrobiálních kolonií MeSH
• půda analýza   MeSH
• půdní mikrobiologie * MeSH
• roční období MeSH
• spory hub růst a vývoj   izolace a purifikace   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• biologické markery MeSH
• hnůj MeSH
• mastné kyseliny MeSH
• minerály 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