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Plant and microbial uptake and allocation of organic and inorganic nitrogen related to plant growth forms and soil conditions at two subarctic tundra types

Sørensen, P L; Clemmensen, K E; Michelsen, A; Jonasson, S and Ström, Lena LU (2008) In Arctic, Antarctic and Alpine Research 40(1). p.171-180
Abstract
In order to follow the uptake and allocation of N in different plant functional types and microbes in two tundra ecosystems differing in nutrient availability, we performed a 15N-labeling experiment with three N forms and followed the partitioning of 15N label among plants, microorganisms and soil organic matter. At both sites the deciduous dwarf shrub Betula nana and the evergreen Empetrum hermaphroditum absorbed added 15N at rates in the order: NH4+ > NO3− > glycine, in contrast to the graminoid Carex species which took up added 15N at rates in the order NO3− > NH4+ > glycine. Carex transported a high proportion of 15N to aboveground parts, whereas the dwarf shrubs allocated most 15N to underground storage. Enhanced 13C in... (More)
In order to follow the uptake and allocation of N in different plant functional types and microbes in two tundra ecosystems differing in nutrient availability, we performed a 15N-labeling experiment with three N forms and followed the partitioning of 15N label among plants, microorganisms and soil organic matter. At both sites the deciduous dwarf shrub Betula nana and the evergreen Empetrum hermaphroditum absorbed added 15N at rates in the order: NH4+ > NO3− > glycine, in contrast to the graminoid Carex species which took up added 15N at rates in the order NO3− > NH4+ > glycine. Carex transported a high proportion of 15N to aboveground parts, whereas the dwarf shrubs allocated most 15N to underground storage. Enhanced 13C in Betula nana roots represents the first field evidence of uptake of intact glycine by this important circumpolar plant. Plant and microbial uptake of label was complementary as plants took up more inorganic than organic N, while microbes preferred organic N. Microbes initially took up a large part of the added label, but over the following four weeks microbial 15N decreased by 50% and most 15N was recovered in soil organic matter, while a smaller but slowly increasing proportion was retained in plant biomass. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Arctic, Antarctic and Alpine Research
volume
40
issue
1
pages
171 - 180
publisher
Institute of Arctic and Alpine Research
external identifiers
  • wos:000252869000019
  • scopus:38949205905
ISSN
1938-4246
DOI
10.1657/1523-0430(06-114)[SORENSEN]2.0.CO;2
language
English
LU publication?
yes
id
108e9862-ee14-42cb-b6f4-2455fcb4a983 (old id 620277)
date added to LUP
2007-12-17 13:49:06
date last changed
2017-10-01 03:54:59
@article{108e9862-ee14-42cb-b6f4-2455fcb4a983,
  abstract     = {In order to follow the uptake and allocation of N in different plant functional types and microbes in two tundra ecosystems differing in nutrient availability, we performed a 15N-labeling experiment with three N forms and followed the partitioning of 15N label among plants, microorganisms and soil organic matter. At both sites the deciduous dwarf shrub Betula nana and the evergreen Empetrum hermaphroditum absorbed added 15N at rates in the order: NH4+ > NO3− > glycine, in contrast to the graminoid Carex species which took up added 15N at rates in the order NO3− > NH4+ > glycine. Carex transported a high proportion of 15N to aboveground parts, whereas the dwarf shrubs allocated most 15N to underground storage. Enhanced 13C in Betula nana roots represents the first field evidence of uptake of intact glycine by this important circumpolar plant. Plant and microbial uptake of label was complementary as plants took up more inorganic than organic N, while microbes preferred organic N. Microbes initially took up a large part of the added label, but over the following four weeks microbial 15N decreased by 50% and most 15N was recovered in soil organic matter, while a smaller but slowly increasing proportion was retained in plant biomass.},
  author       = {Sørensen, P L and Clemmensen, K E and Michelsen, A and Jonasson, S and Ström, Lena},
  issn         = {1938-4246},
  language     = {eng},
  number       = {1},
  pages        = {171--180},
  publisher    = {Institute of Arctic and Alpine Research},
  series       = {Arctic, Antarctic and Alpine Research},
  title        = {Plant and microbial uptake and allocation of organic and inorganic nitrogen related to plant growth forms and soil conditions at two subarctic tundra types},
  url          = {http://dx.doi.org/10.1657/1523-0430(06-114)[SORENSEN]2.0.CO;2},
  volume       = {40},
  year         = {2008},
}