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| Titel |
Contribution of different grass species to plant-atmosphere ammonia exchange in intensively managed grassland |
| VerfasserIn |
M. Mattsson, B. Herrmann, S. Jones, A. Neftel, M. A. Sutton, J. K. Schjoerring |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 1 ; Nr. 6, no. 1 (2009-01-09), S.59-66 |
| Datensatznummer |
250003315
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| Publikation (Nr.) |
 copernicus.org/bg-6-59-2009.pdf |
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| Zusammenfassung |
| Species diversity in grasslands usually declines with increasing input of
nitrogen from fertilizers or atmospheric deposition. Conversely,
species diversity may also impact the build-up of soil and plant nitrogen
pools. One important pool is NH3/NH4+ which also can be
exchanged between plant leaves and the atmosphere. Limited information is
available on how plant-atmosphere ammonia exchange is related to species
diversity in grasslands. We have here investigated grass species abundance
and different foliar nitrogen pools in 4-year-old intensively managed
grassland. Apoplastic pH and NH4+ concentrations of the 8 most
abundant species (Lolium perenne, Phleum pratense, Festuca pratensis,
Lolium multiflorum, Poa pratensis, Dactylis glomerata, Holcus lanatus, Bromus mollis)
were used to calculate stomatal NH3 compensation
points. Apoplastic NH4+ concentrations differed considerably among
the species, ranging from 13 to 117 μM, with highest values in Festuca pratensis. Also
apoplastic pH values varied, from pH 6.0 in Phleum pratense
to 6.9 in Dactylis glomerata. The observed
differences in apoplastic NH4+ and pH resulted in a large span of
predicted values for the stomatal NH3 compensation point which ranged
between 0.20 and 6.57 nmol mol−1. Three species (Lolium perenne,
Festuca pratensis and Dactylis glomerata) had
sufficiently high NH3 compensation point and abundance to contribute to
the bi-directional NH3 fluxes recorded over the whole field. The other
5 grass species had NH3 compensation points considerably below the
atmospheric NH3 concentration and were thus not likely to contribute to
NH3 emission but only to NH3 uptake from the atmosphere. Evaluated
across species, leaf bulk-tissue NH4+ concentrations correlated
well (r2=0.902) with stomatal NH3 compensation points calculated
on the basis of the apoplastic bioassay. This suggests that leaf tissue
NH4+ concentrations combined with data for the frequency
distribution of the corresponding species can be used for predicting the
NH3 exchange potential of a mixed grass sward. |
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