XVI International Botanical Congess

Photosynthesis is sensitive to leaf physiology, it has become useful in quantifying plant responses to many environmental and anthropogenic variables. Chlorophyll a fluorescence spectroscopy is a sensitive method for assessing the state of primary events in photosynthesis. Recent advances in the acquisition and interpretation of fluorescence data makes intensive ecological screening of plants possible. The purpose of this investigation is to compare the effects of O3 and CO2 concentrations and open-top chamber environments on the fluorescence JIP-test parameters from five European tree species. In response to O3, CO2 significant reductions in energy fluxes and quantum efficiencies were recorded per leaf cross section, due to a decrease in the number of reaction centres per cross section. An increase was recorded in all energy fluxes and quantum efficiencies per reaction centre which partially compensated for the reductions per leaf cross section.