The photosynthetic irradiance-response of Norway spruce exposed to a long-term elevation of CO2 concentration
1997
Marek, M.V. | Sprtova, M. | Kalina, J. (Akademie Ved, Brno (Czech Republic). Ustav Krajinne Ekologie)
During an open-top chamber experiment performed in a mountain stand of young Norway spruce (Picea abies), the trees were exposed to one of two CO2 concentrations (ambient CO2, AC, or AC + 350 micromol mol(-1) = elevated CO2, EC) continuously over three growing seasons. To evaluate the EC influence, measurements of the relations between the rate of net CO2 uptake (PN) and incidental photosynthetically active photon flux density (PPFD), as well as the content of photosynthetic pigments and chlorophyll (Chl) a fluorescence were taken in the third growing season. The short-term response to EC was evident mainly on ribulose-1,5-bisphosphate carboxylase/oxygenase kinetics without any significant change to the utilization of radiant energy. The long-term effect of EC was responsible for a decrease in PN, content of Chl a + b, Fv/Fm ratio, quantum yield of fluorescence, and photochemical quenching.
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