Mixedwood conifer trial to compare ectomycorrhizal and arbuscular fungal effects on soil organic matter decay
Data files
Dec 12, 2024 version files 104.90 KB
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humus_layer_Agaricomycete_community.xlsx
77.29 KB
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humus_layer_mass.xlsx
11 KB
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humus_layer_properties.xlsx
14.83 KB
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README.md
1.78 KB
Abstract
The purportedly enhanced decay of soil organic matter (SOM) by ectomycorrhizal fungi (EMF), in contrast to arbuscular mycorrhiza (AMF), was tested in a 30-year old mixedwood trial. Total peroxidase activity, including manganese-peroxidase (MnP), and mass of the humus layer were compared between Pseudotsuga menziesii (EMF) and Thuja plicata (AMF) across a natural productivity gradient. We found total peroxidase and MnP activity diverged between hosts as humus C:N increased, culminating in 3- to 4-fold greater enzyme activity for EMF on low fertility soils. This edaphic effect also correlated significantly with exchangeable Mn, highlighting a possible further restriction on SOM turnover by EMF. Peroxidase activity was well aligned with EMF species other than Cortinariaceae, notably Piloderma olivaceum and Piloderma sphaerosporum. The 3-fold decline in humus mass with decreasing soil fertility under P. menziesii, unlike T. plicata, was strong affirmation that EMF engaged in organic N liberation can lead to reductions in SOMcarbon sequestration
README: Mixedwood conifer trial to compare ectomycorrhizal and arbuscular fungal effects on soil organic matter decay
https://doi.org/10.5061/dryad.s1rn8pkh9
Description of the data and file structure
Files and variables
File: humus_layer_Agaricomycete_community.xlsx
Description: Agaricomycete fungal community
Variables
- fungal species by read depth for each plot
File: humus_layer_properties.xlsx
Description: Humus layer properties
Variables
- C;N ratio, exchangeable Mn, pH, peroxidase activity and ergosterol
File: humus_layer_mass.xlsx
Description: Humus layer mass
Variables
- organic matter mass
Mixedwood conifer trial to compare ectomycorrhizal and arbuscular fungal effects on soil organic matter decay
Included are the humus layer properties and mass data, along with Agaricomycete fungal communities, for a mixed wood trial with western redcedar and coastal Douglas-fir. Results are focused on organic matter dynamics via peroxidase activity.
Description of the data and file structure
Column one is the physical plot number. Column two is the stand type treatment and column three is the density treatment. Column 4 is the subsample for the forest floor properties, while the remaining columns are the data.
The main data sets are the forest floor (or organic horizons as the surface) properties under each stand type, including chemistry (C:N ratio and exchangeable Mn), peroxidase activity, ergosterol, organic matter mass and fungal community.
Sharing/Access information
All data used in the manuscript are included in this Dryad submission. Further questions about the data can be made through the British Columbia Ministry of Forests
Methods
The assay method for total and Mn-dependent peroxidase activity was based on oxidative coupling of DMAB (3-dimethylaminobenzoic acid) and MBTH (3-methyl-2-benzothiazolinone hydrazone hydrochloride) in the presence of Mn2+ and H2O2. The residual peroxidase activity not dependent on Mn as a cofactor was subtracted based on reactions in which MnSO4 was replaced by a chelator (2 mM Na2-EDTA-2H2O). Substrate controls for background absorption unrelated to enzyme activity were supernatants plus reaction solutions without H2O2, while boiled samples were used as negative controls to confirm enzyme involvement in the colour change. We assayed 2 subsamples per composite for peroxidase activity (= 6 readings per plot). Enzyme activity was expressed as μmol h-1 g-1 dry soil.
Humus samples were freeze-dried and ground with a ring mill before DNA extraction. Briefly, the full length ITS region was amplified in duplicate from template DNA using high-fidelity Phusion polymerase and fusion primers and sequenced on a Sequel II instrument at the Integrated Microbiome Resource facility (Halifax, Canada). Fastq files were quality filtered and binned into amplicon sequence variants (ASVs) using the DADA2 software package in R. Taxonomy was assigned using DADA2’s assignTaxonomy() function and the UNITE database. Species were further assigned to functional guild using FUNguild and published literature.