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Canopy uptake of 15NHU+2083 by four temperate tree species and the interaction with leaf properties

Tijdschriftbijdrage - Tijdschriftartikel

Ondertitel:Canopy uptake of 15NH3 by four temperate tree species and the interaction with leaf properties
Tree canopies are believed to act as a sink of atmospheric ammonia (NH3). However, few studies have compared the uptake efficiency of different tree species. This study assessed the uptake of 15N-labelled NH3 at 5, 20, 50 and 100 ppbv by leaves and twigs of potted silver birch, European beech, pedunculate oak and Scots pine saplings in June, August and September 2008. Additionally, foliar uptake of 13C-labelled carbon dioxide (13CO2) and leaf stomatal characteristics were determined per species and treatment date and the relation with 15NH3 uptake was assessed. Both 15NH3 and 13CO2 uptake were affected by tree species and treatment date, but only 15NH3 uptake was influenced by the applied NH3 concentration. Depending on the treatment date, 15NH3 uptake by leaves and twigs was highest at 5 (September), 20 (June) or 50 (August) ppb. Birch, beech and oak leaves showed the highest uptake in August, while for pine needles this was in June, and except at 5 ppb in June the 15NH3 uptake was always higher for the deciduous species than for pine. For all species except beech 13CO2 uptake was highest in August and on every treatment date the 13CO2 uptake by leaves of deciduous species was significantly higher than by pine needles. Leaf characteristics and 13CO2 uptake did not provide a strong explanation for the observed differences in 15NH3 uptake. This study shows that on the short term a high interspecific variability exists in NH3 uptake, which depends on the time in the growing season.
Tijdschrift: Water, Air & Soil Pollution
ISSN: 0049-6979
Issue: 9
Volume: 223
Pagina's: 5643 - 5657
Jaar van publicatie:2012