title: Effect of Chalara longipes on decomposition of humic acids from Picea abies needle litter.
abstract: The effect of the saprotrophic ascomycete Chalara longipes on the decomposition of humic acids was determined in a cultivation experiment. The fungus was incubated in liquid cultures in a full-strength (F system) and an organic nitrogen-free medium (F-N system), both amended with pure humic acids isolated from spruce forest litter. Fungal biomass production was highest in the F system with humic acids and lowest in the F-N system, the effect of organic nitrogen and humic acids being significant (p < 0.05). The presence of organic nitrogen seems to be essential for growth. The fungus utilized humic acids; molar mass distribution in media obtained by gel-permeation chromatography showed decrease in the humic acids fraction. Decolorization of the media reached 75 and 64 % in the F and F-N systems, respectively. The molar mass of humic acids probably also decreased as estimated from the increase in the absorbance A465/A665 (A4/A6) ratio. It is assumed that the utilization of humic acids may be mediated by the production of organic acids (as their components) and production of some oxidative enzymes.
authors.affiliation: Institute of Botany, Academy of Sciences of the Czech Republic, 252 43 Průhonice, Czechia.
authors.forename: O
authors.initials: O
authors.lastname: Koukol
authors.forename: M
authors.initials: M
authors.lastname: Gryndler
authors.forename: F
authors.initials: F
authors.lastname: Novák
authors.forename: M
authors.initials: M
authors.lastname: Vosátka
mesh_terms: D001203:Ascomycota / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018533:Biomass; D017753:Ecosystem; D006812:Humic Substances / Q000032:analysis*; D008970:Molecular Weight; D028222:Picea / Q000737:chemistry*; D012988:Soil Microbiology
chemical_list: D006812:Humic Substances