Effects of ozone impact on the gas exchange and chlorophyll fluorescence of juvenile birch stems (Betula pendula Roth.).
Effects of ozone impact on gas exchange and chlorophyll fluorescence of juvenile birch (Betula pendula) stems and leaves were investigated. Significant differences in the response of leaves and stems to ozone were found. In leaves, O3 exposure led to a significant decline in photosynthetic rates, whereas stems revealed an increased dark respiration and a concomitant increase in corticular photosynthesis. In contrast to birch leaves, corticular photosynthesis appeared to support the carbon balance of stems or even of the whole-tree under O3 stress. The differences in the ozone-response between leaves and stems were found to be related to ozone uptake rates, and thus to inherent differences in leaf and stem O3 conductance.
Wittmann
Christiane
C
Department of Applied Botany, University of Duisburg-Essen, Universitätsstr. 5, 45117 Essen, Germany.
Matyssek
Rainer
R
Pfanz
Hardy
H
Humar
Maja
M
D000393:Air Pollutants / Q000633:toxicity*; D029662:Betula / Q000254:growth & development / Q000378:metabolism*; D018533:Biomass; D002734:Chlorophyll / Q000378:metabolism*; D005453:Fluorescence; D010083:Oxidants, Photochemical / Q000633:toxicity*; D010126:Ozone / Q000633:toxicity*; D010788:Photosynthesis; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D018547:Plant Stems / Q000254:growth & development / Q000378:metabolism*; D018526:Plant Transpiration; D013472:Sunlight
D000393:Air Pollutants; D010083:Oxidants, Photochemical; D002734:Chlorophyll; D010126:Ozone