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Title: Phytotoxicity of air pollutants: evidence for the photodetoxification of SO/sub 2/ but not O/sub 3/

Journal Article · · Plant Physiol.; (United States)
OSTI ID:6848913

Pisum sativum L. cv Alsweet (garden pea) and Lycopersicon esculentum flacca Mill. (tomato) were used to evaluate the phytotoxicity of SO/sub 2/ and O/sub 3/ in the light and dark. Plants were grown in controlled environment chambers and exposed to SO/sub 2/ or O/sub 3/ in the light or dark at the same environmental conditions at which they were grown. The pea plants were treated with fusicoccin to ensure open stomata in the dark; the stomata of the tomato mutant remained open in the dark. Both species exhibited 64% to 80% less foliar necrosis following exposure to SO/sub 2/ (0.5 to 1.0 microliter per liter for 2 hours) in the light than in the dark. The decrease in SO/sub 2/ injury for light versus dark exposed plants was greater in fully expanded than expanding leaves. Both species exhibited 30% greater foliar necrosis following exposure to O/sub 3/ (0.2 microliter per liter for 2 hours) in the light than dark. The increase in O/sub 3/ injury in the light versus dark was similar for leaves at all stages of expansion. Leaf conductance to water vapor was 7% to 11% and 23% higher in the light than dark for fusicoccin-treated peas and tomato plants, respectively, indicating greater foliar uptake of both pollutants in the light than dark. Thus, the decrease SO/sub 2/ toxicity in the light was not associated with pollutant uptake, but rather the metabolism of SO/sub 2/. In contrast, the increased toxicity of O/sub 3/ in the light was at least in part associated with increased uptake or could not be separated from it.

Research Organization:
Univ. of California, Riverside
OSTI ID:
6848913
Journal Information:
Plant Physiol.; (United States), Vol. 74:4
Country of Publication:
United States
Language:
English