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Dynamics of phosphorus translocation in intact ectomycorrhizal systems: Non-destructive monitoring using a beta-scanner

Timonen, Sari ; Finlay, Roger D. ; Olsson, Stefan and Söderström, Bengt LU (1996) In FEMS Microbiology Ecology 19(3). p.171-180
Abstract
Phosphorus uptake and translocation through intact mycelial systems of Paxillus involutus and Suillus variegatus infecting Pinus contorta seedlings was monitored non-destructively using a beta-scanner. Mycorrhizal plants were grown in flat perspex chambers (20 x 6 cm(2)) and root growth was restricted to the upper portion of each chamber enabling mycelial translocation to be studied over distances of up to 15 cm. P-32 was supplied, either directly to distal parts of the extending mycelium, or to single, cut mycelial strands in feeding dishes. Two-dimensional patterns of activity were accumulated as scans with a lateral resolution of 5 mm and a longitudinal resolution of 3-4 mm. No distinct translocation front could be detected but patterns... (More)
Phosphorus uptake and translocation through intact mycelial systems of Paxillus involutus and Suillus variegatus infecting Pinus contorta seedlings was monitored non-destructively using a beta-scanner. Mycorrhizal plants were grown in flat perspex chambers (20 x 6 cm(2)) and root growth was restricted to the upper portion of each chamber enabling mycelial translocation to be studied over distances of up to 15 cm. P-32 was supplied, either directly to distal parts of the extending mycelium, or to single, cut mycelial strands in feeding dishes. Two-dimensional patterns of activity were accumulated as scans with a lateral resolution of 5 mm and a longitudinal resolution of 3-4 mm. No distinct translocation front could be detected but patterns of accumulation of label in the mycorrhizal roots were not consistent with movement by simple diffusion. Activity in translocating hyphae became visible only after the activity in mycorrhizal root lips had been visible for a few days. In all cases there was a lag period of 20-50 hours before P-32 could be detected in mycorrhizal root tips. Pre-feeding with unlabelled phosphate had no effect on this lag period. This implies continuous translocation of phosphate at low concentrations and a lag period due to the time needed for detectable levels of phosphate to accumulate in mycorrhizal roots. Thus the minimum velocity of phosphate movement in the hyphae would be 7.5 mm/h, if the first molecules of P-32 arriving at the roots could be detected and the transport distance is 15 cm. Accumulation of phosphate to the roots was fairly constant, but not linear. The phosphorus uptake rate by intact mycelial margins was nearly four orders of magnitude higher than the uptake rate of cut mycorrhizal strands. The results indicate that the fine, foraging hyphae are better suited for nutrient uptake than mycelial strands and that phosphorus translocation in the hyphae occurs by active translocation of small amounts rather than by mass flow. (Less)
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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Ectomycorrhiza, Mycelium, Nutrient uptake, Phosphorus translocation, Pinus contorta
in
FEMS Microbiology Ecology
volume
19
issue
3
pages
171 - 180
publisher
Oxford University Press
ISSN
1574-6941
DOI
10.1111/j.1574-6941.1996.tb00210.x
language
English
LU publication?
yes
id
6c4ef805-8096-41fe-b65d-1ade7b24bbd4 (old id 2226278)
date added to LUP
2016-04-01 12:30:27
date last changed
2020-09-23 15:14:36
@article{6c4ef805-8096-41fe-b65d-1ade7b24bbd4,
  abstract     = {{Phosphorus uptake and translocation through intact mycelial systems of Paxillus involutus and Suillus variegatus infecting Pinus contorta seedlings was monitored non-destructively using a beta-scanner. Mycorrhizal plants were grown in flat perspex chambers (20 x 6 cm(2)) and root growth was restricted to the upper portion of each chamber enabling mycelial translocation to be studied over distances of up to 15 cm. P-32 was supplied, either directly to distal parts of the extending mycelium, or to single, cut mycelial strands in feeding dishes. Two-dimensional patterns of activity were accumulated as scans with a lateral resolution of 5 mm and a longitudinal resolution of 3-4 mm. No distinct translocation front could be detected but patterns of accumulation of label in the mycorrhizal roots were not consistent with movement by simple diffusion. Activity in translocating hyphae became visible only after the activity in mycorrhizal root lips had been visible for a few days. In all cases there was a lag period of 20-50 hours before P-32 could be detected in mycorrhizal root tips. Pre-feeding with unlabelled phosphate had no effect on this lag period. This implies continuous translocation of phosphate at low concentrations and a lag period due to the time needed for detectable levels of phosphate to accumulate in mycorrhizal roots. Thus the minimum velocity of phosphate movement in the hyphae would be 7.5 mm/h, if the first molecules of P-32 arriving at the roots could be detected and the transport distance is 15 cm. Accumulation of phosphate to the roots was fairly constant, but not linear. The phosphorus uptake rate by intact mycelial margins was nearly four orders of magnitude higher than the uptake rate of cut mycorrhizal strands. The results indicate that the fine, foraging hyphae are better suited for nutrient uptake than mycelial strands and that phosphorus translocation in the hyphae occurs by active translocation of small amounts rather than by mass flow.}},
  author       = {{Timonen, Sari and Finlay, Roger D. and Olsson, Stefan and Söderström, Bengt}},
  issn         = {{1574-6941}},
  keywords     = {{Ectomycorrhiza; Mycelium; Nutrient uptake; Phosphorus translocation; Pinus contorta}},
  language     = {{eng}},
  number       = {{3}},
  pages        = {{171--180}},
  publisher    = {{Oxford University Press}},
  series       = {{FEMS Microbiology Ecology}},
  title        = {{Dynamics of phosphorus translocation in intact ectomycorrhizal systems: Non-destructive monitoring using a beta-scanner}},
  url          = {{http://dx.doi.org/10.1111/j.1574-6941.1996.tb00210.x}},
  doi          = {{10.1111/j.1574-6941.1996.tb00210.x}},
  volume       = {{19}},
  year         = {{1996}},
}