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| Titel |
Improved sapflow methodology reveals considerable night-time ozone uptake by Mediterranean species |
| VerfasserIn |
S. Mereu, G. Gerosa, A. Finco, L. Fusaro, B. Muys, F. Manes |
| 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. 12 ; Nr. 6, no. 12 (2009-12-23), S.3151-3162 |
| Datensatznummer |
250004237
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| Publikation (Nr.) |
 copernicus.org/bg-6-3151-2009.pdf |
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| Zusammenfassung |
| Due to the evident tropospheric ozone impact on plant productivity, an
accurate ozone risk assessment for the vegetation has become an issue. There
is a growing evidence that ozone stomatal uptake may also take place at
night and that the night-time uptake may be more damaging than diurnal
uptake. Estimation of night-time uptake in the field is complicated because
of instrumental difficulties. Eddy covariance technology is not always
reliable because of the low turbulence at night. Leaf level porometry is
defective at relative humidity above 70% which often takes place at
night. Improved sap flow technology allows to estimate also slow flows that
usually take place at night and hence may be, at present, the most
trustworthy technology to measure night-time transpiration and hence to
derive canopy stomatal conductance and ozone uptake at night. Based on
micrometeorological data and the sap flow of three Mediterranean woody
species, the night-time ozone uptake of these species was evaluated during a
summer season as drought increased. Night-time ozone uptake was from 10%
to 18% of the total daily uptake when plants were exposed to a weak
drought, but increased up to 24% as the drought became more pronounced.
The percentage increase is due to a stronger reduction of diurnal stomatal
conductance than night-time stomatal conductance. |
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