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Phosphatase activity does not limit the microbial use of low molecular weight organic-P substrates in soil

Fransson, Ann-Mari LU and Jones, David L (2007) In Soil Biology & Biochemistry 39(5). p.1213-1217
Abstract
Plant roots and soil microorganisms contain significant quantities of low molecular weight (MW) phosphorylated nucleosides and sugars. Consequently.. upon death these can represent a significant input of organic-P to the soil. Some of these organic-P substrates must first be dephosphorylated by phosphatases before being assimilated by the soil microbial community while others can be taken up directly from soil solution. To determine whether sorption or phosphatase activity was limiting the bioavailability of low MW organic-P in soil we compared the microbial uptake and C mineralization of a range of C-14-labeled organic-P substrates [glucose-6-phosphate, adenosine monophosphate (AMP), adenosine diphosphate (ADP) and adenosine triphosphate... (More)
Plant roots and soil microorganisms contain significant quantities of low molecular weight (MW) phosphorylated nucleosides and sugars. Consequently.. upon death these can represent a significant input of organic-P to the soil. Some of these organic-P substrates must first be dephosphorylated by phosphatases before being assimilated by the soil microbial community while others can be taken up directly from soil solution. To determine whether sorption or phosphatase activity was limiting the bioavailability of low MW organic-P in soil we compared the microbial uptake and C mineralization of a range of C-14-labeled organic-P substrates [glucose-6-phosphate, adenosine monophosphate (AMP), adenosine diphosphate (ADP) and adenosine triphosphate (ATP)] to that of the parent compounds (adenosine and glucose). In a fertile grassland soil we showed that at low organic-P substrate concentrations (< 0.5 mM) phosphatase activity did not limit microbial uptake or mineralization in comparison to their non-phosphorylated counterparts. However, at high substrate concentrations (1-10 mM) the mineralization of the organic-P compounds was significantly lower than that of the nonphosphorylated compounds suggesting that phosphatase activity or microbial transporter capacity limited bioavailability. Sorption to the solid phase followed the series glucose < adenosine < G-6-P < AMP < ADP=ATP. However, sorption of the organic-P compounds to the solid phase did not appear to greatly affect bioavailability. The high adenosine mineralization capacity of the microbial biomass suggests that nucleosides may represent a significant source of C and N to the soil microbial biomass. We conclude that at low organic-P substrate concentrations typical of those in soil, neither phosphatase activity nor sorption greatly limits their bioavailability. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
phosphatases, sorption, organic phosphorus, mineralization, cycling, nutrient, dissolved organic nitrogen, extracellular enzyme activity
in
Soil Biology & Biochemistry
volume
39
issue
5
pages
1213 - 1217
publisher
Elsevier
external identifiers
  • wos:000245415900026
  • scopus:33847614854
ISSN
0038-0717
DOI
10.1016/j.soilbio.2006.11.014
language
English
LU publication?
yes
id
60b0cf93-90a4-4e84-b5a4-6a2e422dce76 (old id 666638)
date added to LUP
2007-12-07 09:45:01
date last changed
2017-09-03 04:38:59
@article{60b0cf93-90a4-4e84-b5a4-6a2e422dce76,
  abstract     = {Plant roots and soil microorganisms contain significant quantities of low molecular weight (MW) phosphorylated nucleosides and sugars. Consequently.. upon death these can represent a significant input of organic-P to the soil. Some of these organic-P substrates must first be dephosphorylated by phosphatases before being assimilated by the soil microbial community while others can be taken up directly from soil solution. To determine whether sorption or phosphatase activity was limiting the bioavailability of low MW organic-P in soil we compared the microbial uptake and C mineralization of a range of C-14-labeled organic-P substrates [glucose-6-phosphate, adenosine monophosphate (AMP), adenosine diphosphate (ADP) and adenosine triphosphate (ATP)] to that of the parent compounds (adenosine and glucose). In a fertile grassland soil we showed that at low organic-P substrate concentrations (&lt; 0.5 mM) phosphatase activity did not limit microbial uptake or mineralization in comparison to their non-phosphorylated counterparts. However, at high substrate concentrations (1-10 mM) the mineralization of the organic-P compounds was significantly lower than that of the nonphosphorylated compounds suggesting that phosphatase activity or microbial transporter capacity limited bioavailability. Sorption to the solid phase followed the series glucose &lt; adenosine &lt; G-6-P &lt; AMP &lt; ADP=ATP. However, sorption of the organic-P compounds to the solid phase did not appear to greatly affect bioavailability. The high adenosine mineralization capacity of the microbial biomass suggests that nucleosides may represent a significant source of C and N to the soil microbial biomass. We conclude that at low organic-P substrate concentrations typical of those in soil, neither phosphatase activity nor sorption greatly limits their bioavailability.},
  author       = {Fransson, Ann-Mari and Jones, David L},
  issn         = {0038-0717},
  keyword      = {phosphatases,sorption,organic phosphorus,mineralization,cycling,nutrient,dissolved organic nitrogen,extracellular enzyme activity},
  language     = {eng},
  number       = {5},
  pages        = {1213--1217},
  publisher    = {Elsevier},
  series       = {Soil Biology & Biochemistry},
  title        = {Phosphatase activity does not limit the microbial use of low molecular weight organic-P substrates in soil},
  url          = {http://dx.doi.org/10.1016/j.soilbio.2006.11.014},
  volume       = {39},
  year         = {2007},
}