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Effect of increasing ozone and carbon dioxide on photosynthetic and related biochemical properties of two silver birch clones during three years of exposure
2002
Riikonen, J. (Finnish Forest Research Institute, Suonenjoki (Finland). Suonenjoki Research Station) | Holopainen, T. | Oksanen, E. | Vapaavuori, E.
Under elevated CO2 photosynthesis was 15-50% higher than in chamber controls depending on the weather conditions of the growing seasons. When measured at 360 ppm CO2 both elevated CO2 and elevated CO2 + O3 treatments decreased net photosynthesis, stomatal conductance and also transpiration, indicating downregulation of photosynthesis at elevated CO2
Afficher plus [+] Moins [-]Moderation of CO2 induced gas exchange and growth responses by elevated tropospheric O3
2002
Karnosky, D. F. (Michigan Technological University, Houghton (USA). School of Forestry and Wood Products) | Sober, A. | Sharma, P. | Kubiske, M. | Isebrands, J.G.
Stimulation of photosynthesis by elevated CO2 has been consistently found for aspen but not for maple. Similar responses have been shown for growth. In contrast, O3 causes decreased levels of photosynthesis and growth in aspen but does not appear to impact sugar maple significantly. When the pollutants co-occur, CO2 induced enhancements in photosynthesis and growth are moderated so that trees in CO2 and O3 treatments respond similarly to those in control rings. In this presentation, we will provide a physiological interpretation of our results in modelling growth response under future atmospheric conditions
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