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Updated: Jun 1, 2026
12:33
High-throughput Fluorometric Measurement of Potential Soil Extracellular Enzyme Activities
Published on: November 15, 2013
Substrate supply, fine roots, and temperature control proteolytic enzyme activity in temperate forest soils
Edward R Brzostek1, Adrien C Finzi
1Department of Biology, Boston University, Boston, Massachusetts 02215, USA. ebrzost@bu.edu
Ecology
|June 14, 2011
Summary
Soil enzyme activity, crucial for nutrient cycling, is influenced by temperature and substrate. Ectomycorrhizal fungi associated with trees significantly impact nitrogen cycling more than arbuscular mycorrhizal fungi.
Area of Science:
- Soil Science
- Ecology
- Biogeochemistry
Background:
- Extracellular enzyme activity, vital for soil organic matter decomposition and nutrient release, is regulated by temperature and substrate availability.
- Proteolytic enzymes are key in nitrogen (N) cycling by breaking down proteinaceous soil organic matter (SOM).
- Understanding these factors is crucial for predicting forest soil N dynamics.
Purpose of the Study:
- To investigate the effects of temperature and substrate availability on proteolytic enzyme activity in temperate forest soils.
- To compare the activity of proteolytic, chitinolytic, and ligninolytic enzymes between tree species associated with ectomycorrhizal (EM) and arbuscular mycorrhizal (AM) fungi.
- To determine the role of tree roots in regulating enzyme activity based on mycorrhizal association.
Main Methods:
- Field measurements of soil enzyme activity under varying temperature and substrate conditions.
- Enzyme assays for proteolytic, chitinolytic, and ligninolytic activities.
- Comparison of enzyme activities across forest stands dominated by EM and AM tree species.
Main Results:
- Temperature limitation of proteolytic enzymes occurred only at low early-season temperatures (approx. 4°C).
- Substrate limitation of proteolytic activity was evident throughout much of the growing season.
- Ligninolytic enzyme activity was higher in soils with ectomycorrhizal tree species.
- Roots of EM species, but not AM species, significantly controlled proteolytic, chitinolytic, and ligninolytic enzyme activity.
Conclusions:
- Climate warming may have a limited impact on soil nitrogen cycling without increased substrate availability.
- Changes in belowground carbon allocation by trees, particularly those affecting ectomycorrhizal associations, are likely to have a greater influence on nitrogen cycling.
- Ectomycorrhizal fine roots play a critical role in regulating soil N-cycling enzymes.
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