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| Titel |
The influence of phenolic acids on microbiological activity of soils |
| VerfasserIn |
Anna Gunina, Mikhail Biryukov |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046120
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| Zusammenfassung |
| Phenolic acids are non-specific organic compounds of soil organic matter (SOM). These
compounds are formed during the decomposition of plant residues or are released within root
exudation. The concentration of phenolic acids in soil depends on microbial uptake rate,
fixation by soil matrix and microbial decomposition. Phenolic acids are known to be of great
significance in the regulating of plant growth and soil microorganisms activity, take part
in biosynthesis of lignin, regulating the cycles of the nutrients (the processes of
nitrification and denitrification). Despite phenolic acids being bioactive substances
may cause the stimulating and inhibiting effects on microorganisms and they may
utilize phenolic acids as a carbon source. Nevertheless on the broad spectrum of
ecological functions, the influence of the phenolic acids on majority soil decomposers is
largely unknown. The main hypothesis of our work was that some natural organic
substances derived from plant residues in autumn may depress the activity of SOM
decomposers.
To prove this hypothesis we used samples of soil (0-5 cm) and litter collected in
autumn 2009 under 2 vegetation types: coniferous forest (Picea abies) and broadleaf
forest (Acer platanoides). Soil samples were sieved (2.0 mm) and stored at 5 Ë
C.
We studied the quantitative and qualitative composition of phenolic acids of the
soils and litter under deciduous and coniferous trees using HPLC and GC-MS.
The dominant substances were: p-hydroxybenzoic, vanillic, salicylic and benzoic
acids The amount of these phenolic compounds in the maple and spruce litters
ranged from 0.6 to 85.3 mg kg-1 for individual acids and the concentration of
these compounds in maple litter was higher than in the spruce litter. The patterns
of phenolic acids composition were similar in soils under the spruce and maple
trees.
The effect of phenolic acids on soils microbial activity was determined in two types
of laboratory experiments: i) addition of the individual phenolic acids to the soil
samples or ii) to the prokaryotes suspension, which were prepared from investigated
soils by nystatin addition. The concentrations of phenolic acids were based on their
qualitative and quantitative composition in litter and in the soil solution. On days 6
and 14, the soil samples treated with phenolic acids were analyzed for CO2 efflux,
microbial biomass C (method of substrate induced respiration), protein-degrading
enzyme activity and total enzyme activity. The maximum rate of microbial growth of
prokaryotes was the main parameter of analyzed effect of phenolic acids in the second
experiment.
Protein-degrading enzyme activity for the soil spruce samples on day 6 was higher
than under maple. The protein-degrading enzyme activity in soil spruce samples
decreased for 1.2 times from 6 to 14 day. Similar effects were observed under the
maple. The total microbial activity on days 6 and 14 was higher under the spruce site
1.5 and 2 times, respectively in comparison with the maple site. In contrast to the
enzyme activities the spruce prokaryote community was stimulated by individual
phenolic acids and their mixture. Microbial biomass in the soil spruce samples also
increased. Vanillic and salicylic acids stimulated the maple soil prokaryote community.
Benzoic, p-hydroxybenzoic acids and the mixture caused an inhibition effects on
prokaryote community of the soil under the maple trees, but microbial biomass in the
maple soil samples was not suppressed or even increased by the addition of these
substances.
This work was financially supported by the Russian Federal Programme «Scientific
and scientific-pedagogical personnel» (2009-2013). State contract number P1325 |
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