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Soil Biology & Biochemistry 38 (2006) 32453256 Activities of extracellular enzymes in physically isolated fractions of

Summary: Soil Biology & Biochemistry 38 (2006) 32453256
Activities of extracellular enzymes in physically isolated fractions of
restored grassland soils
Steven D. Allisona,, Julie D. Jastrowb
Department of Ecology and Evolution, University of California, Irvine, 341 Steinhaus Hall, Irvine, CA 92697, USA
Environmental Research Division, Argonne National Laboratory, Argonne, IL 60439-4843, USA
Available online 6 May 2006
Extracellular enzymes degrade complex organic compounds and contribute to carbon turnover in soils. We used physical fractionation
procedures to investigate whether soil carbon is spatially isolated from degradative enzymes across a prairie restoration chronosequence
in Illinois, USA. We found that carbon-degrading enzymes were abundant in all soil fractions, including macroaggregates,
microaggregates, and the clay-sized fraction. The activities of two cellulose-degrading enzymes and a chitin-degrading enzyme were 210
times greater in particulate organic matter (POM) fractions than in bulk soil, consistent with the rapid turnover of POM fractions.
Polyphenol oxidase activity in the clay-sized fraction was 3 times that in the bulk soil, despite a higher mean residence time for carbon in
the clay-sized fraction. For most enzymes, differences in activity among fractions and across the restoration chronosequence diminished
when adjusted for differences in carbon concentrations. However, glycine aminopeptidase activity per unit carbon increased four-fold
across the chronosequence in the clay fraction, while polyphenol oxidase activity declined by 40%. These results suggest that enzyme
production and carbon turnover occur rapidly in POM fractions, but slowly in mineral-dominated fractions where enzymes and their


Source: Allison, Steven D. - Departments of Ecology and Evolutionary Biology & Earth System Science, University of California, Irvine


Collections: Environmental Sciences and Ecology