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Investigating the mechanisms for the opposing pH relationships of fungal and bacterial growth in soil

Rousk, Johannes LU ; Brookes, Philip C. and Bååth, Erland LU (2010) In Soil Biology & Biochemistry 42(6). p.926-934
Abstract
Soil pH is one of the most influential variables in soil, and is a powerful factor in influencing the size, activity and community structure of the soil microbial community. It was previously shown in a century old artificial pH gradient in an arable soil (pH 4.0-8.3) that bacterial growth is positively related to pH, while fungal growth increases with decreasing pH. In an attempt to elucidate some of the mechanisms for this, plant material that especially promotes fungal growth (straw) or bacterial growth (alfalfa) was added to soil samples of the pH gradient in 5-day laboratory incubation experiments. Also, bacterial growth was specifically inhibited by applying a selective bacterial growth inhibitor (bronopol) along the entire pH... (More)
Soil pH is one of the most influential variables in soil, and is a powerful factor in influencing the size, activity and community structure of the soil microbial community. It was previously shown in a century old artificial pH gradient in an arable soil (pH 4.0-8.3) that bacterial growth is positively related to pH, while fungal growth increases with decreasing pH. In an attempt to elucidate some of the mechanisms for this, plant material that especially promotes fungal growth (straw) or bacterial growth (alfalfa) was added to soil samples of the pH gradient in 5-day laboratory incubation experiments. Also, bacterial growth was specifically inhibited by applying a selective bacterial growth inhibitor (bronopol) along the entire pH gradient to investigate if competitive interaction caused the shift in the decomposer community along the gradient. Straw benefited fungal growth relatively more than bacterial, and vice versa for alfalfa. The general pattern of a shift in fungal:bacterial growth with pH was, however, unaffected by substrate additions, indicating that lack of a suitable substrate was not the cause of the pH effect on the microbial community. In response to the bacterial growth inhibition by bronopol, there was stimulation of fungal growth up to pH 7, but not beyond, both for alfalfa and straw addition. However, the accumulation of ergosterol (an indicator of fungal biomass) during the incubation period after adding alfalfa increased at all pHs, indicating that fungal growth had been high at some time during the 5-day incubation following joint addition of alfalfa and bronopol. This was corroborated in a time-series experiment. In conclusion, the low fungal growth at high pH in an arable soil was caused to a large extent by bacterial competition, and not substrate limitation. (C) 2010 Elsevier Ltd. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Acetate incorporation into ergosterol, Decomposer interaction, Soil pH, Bacterial growth, Fungal-to-bacteria ratio, Fungal growth, Leucine, incorporation
in
Soil Biology & Biochemistry
volume
42
issue
6
pages
926 - 934
publisher
Elsevier
external identifiers
  • wos:000277814700008
  • scopus:77950594492
ISSN
0038-0717
DOI
10.1016/j.soilbio.2010.02.009
project
Interaction between fungi and bacteria in soil
Effect of environmental factors on fungal and bacterial growth in soil
Carbon drivers and microbial agents of soil respiration
Microbial carbon-use efficiency
BECC
language
English
LU publication?
yes
id
7081a397-36b8-40b0-b454-f51bcd3d8439 (old id 1617181)
date added to LUP
2010-06-22 13:26:45
date last changed
2018-07-15 04:01:48
@article{7081a397-36b8-40b0-b454-f51bcd3d8439,
  abstract     = {Soil pH is one of the most influential variables in soil, and is a powerful factor in influencing the size, activity and community structure of the soil microbial community. It was previously shown in a century old artificial pH gradient in an arable soil (pH 4.0-8.3) that bacterial growth is positively related to pH, while fungal growth increases with decreasing pH. In an attempt to elucidate some of the mechanisms for this, plant material that especially promotes fungal growth (straw) or bacterial growth (alfalfa) was added to soil samples of the pH gradient in 5-day laboratory incubation experiments. Also, bacterial growth was specifically inhibited by applying a selective bacterial growth inhibitor (bronopol) along the entire pH gradient to investigate if competitive interaction caused the shift in the decomposer community along the gradient. Straw benefited fungal growth relatively more than bacterial, and vice versa for alfalfa. The general pattern of a shift in fungal:bacterial growth with pH was, however, unaffected by substrate additions, indicating that lack of a suitable substrate was not the cause of the pH effect on the microbial community. In response to the bacterial growth inhibition by bronopol, there was stimulation of fungal growth up to pH 7, but not beyond, both for alfalfa and straw addition. However, the accumulation of ergosterol (an indicator of fungal biomass) during the incubation period after adding alfalfa increased at all pHs, indicating that fungal growth had been high at some time during the 5-day incubation following joint addition of alfalfa and bronopol. This was corroborated in a time-series experiment. In conclusion, the low fungal growth at high pH in an arable soil was caused to a large extent by bacterial competition, and not substrate limitation. (C) 2010 Elsevier Ltd. All rights reserved.},
  author       = {Rousk, Johannes and Brookes, Philip C. and Bååth, Erland},
  issn         = {0038-0717},
  keyword      = {Acetate incorporation into ergosterol,Decomposer interaction,Soil pH,Bacterial growth,Fungal-to-bacteria ratio,Fungal growth,Leucine,incorporation},
  language     = {eng},
  number       = {6},
  pages        = {926--934},
  publisher    = {Elsevier},
  series       = {Soil Biology & Biochemistry},
  title        = {Investigating the mechanisms for the opposing pH relationships of fungal and bacterial growth in soil},
  url          = {http://dx.doi.org/10.1016/j.soilbio.2010.02.009},
  volume       = {42},
  year         = {2010},
}