Photosynthesis, chloroplast pigments, and antioxidants in Pinus canariensis under free-air ozone fumigation.
High O3 levels, driving uptake and challenging defense, prevail on the Canary Islands, being associated with the hot and dry summers of the Mediterranean-type climate. Pinus canariensis is an endemic conifer species that forms forests across these islands. We investigated the effects of ozone on photosynthesis and biochemical parameters of P. canariensis seedlings exposed to free-air O3 fumigation at Kranzberg Forest, Germany, where ambient O3 levels were similar to those at forest sites in the Canary Islands. The twice-ambient O3 regime (2 x O3) neither caused visible injury-like chlorotic or necrotic spots in the needles nor significantly affected violaxanthin, antheraxanthin and zeaxanthin levels and the de-epoxidation state of the xanthophyll cycle. In parallel, stomatal conductance for water vapour, net photosynthesis, intercellular CO2 concentration, chlorophyll fluorescence parameters, as well as antioxidant levels were hardly affected. It is concluded that presently prevailing O3 levels do not impose severe stress on P. canariensis seedlings.
Then
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Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Unit of Alpine Timberline Ecophysiology, Rennweg 1, A-6020 Innsbruck, Austria.
Herbinger
K
K
Luis
V C
VC
Heerdt
C
C
Matyssek
R
R
Wieser
G
G
D000975:Antioxidants / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism*; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism; D005651:Fumigation; D018384:Oxidative Stress; D010126:Ozone / Q000494:pharmacology*; D010788:Photosynthesis / Q000187:drug effects*; D028223:Pinus / Q000187:drug effects* / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism
D000975:Antioxidants; D002734:Chlorophyll; D010126:Ozone