The effect of ozone fumigation over one season on photosynthetic processes of Quercus robur seedlings

Autor: P. K. Farage
Rok vydání: 1996
Předmět:
Zdroj: New Phytologist. 134:279-285
ISSN: 1469-8137
0028-646X
DOI: 10.1111/j.1469-8137.1996.tb04632.x
Popis: summary Quercus robur saplings were exposed to elevated O3 (80 nmol mol-1) in hemispherical glasshouses for one growing season in order to assess the effects of this pollutant on photosynthesis. Measurements of chlorophyll fluorescence induction kinetics in mid-summer showed that plants exposed to both control O3 (20 nmol mol−1) and elevated O3 treatments experienced significant photoinhibition of photosynthesis. Elevated O3 increased photoinhibition. At the end of the summer, photosynthetic CO2 uptake, measured at either light saturation or under light-limiting conditions, was not significantly different between plants from the two O3 treatments. Although the maximum rate of carboxylation velocity, as estimated from the response of CO2 uptake to intercellular CO2 concentration, the maximum quantum efficiency and the maximum rate of electron transport measured in vivo were decreased by O3 exposure, the responses differed between plants and, overall, the decreases were not statistically significant. The results suggest that O3 levels that are at present reached for a few days during photochemical episodes in the summer are not sufficient to cause measurable lasting damage to photosynthetic CO2 uptake in oak saplings assessed over one growing season.
Databáze: OpenAIRE
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