Impact of elevated CO2 concentration on dynamics of leaf photosynthesis in Fagus sylvatica is modulated by sky conditions

0440777 - ÚVGZ 2015 RIV GB eng J - Journal Article
Urban, Otmar - Klem, Karel - Holišová, Petra - Šigut, Ladislav - Šprtová, Miroslava - Teslová-Navrátilová, P. - Zitová, Martina - Špunda, Vladimír - Marek, Michal V. - Grace, J.
Impact of elevated CO2 concentration on dynamics of leaf photosynthesis in Fagus sylvatica is modulated by sky conditions.
Environmental Pollution. Roč. 185, FEB 2014 (2014), s. 271-280. ISSN 0269-7491. E-ISSN 1873-6424
R&D Projects: GA MŠMT(CZ) LM2010007; GA ČR(CZ) GAP501/10/0340
Institutional support: RVO:67179843
Keywords : diurnal dynamics * DEPS * european beech * fluorescence * photorespiration * stomatal conductance * xanthophylls
Subject RIV: GK - Forestry
Impact factor: 4.143, year: 2014

It has been suggested that atmospheric CO2 concentration and frequency of cloud cover will increase in future. It remains unclear, however, how elevated CO2 influences photosynthesis under complex clear versus cloudy sky conditions. Accordingly, diurnal changes in photosynthetic responses among beech trees grown at ambient (AC) and doubled (EC) CO2 concentrations were studied under contrasting sky conditions. EC stimulated the daily sum of fixed CO2 and light use efficiency under clear sky. Meanwhile, both these parameters were reduced under cloudy sky as compared with AC treatment. Reduction in photosynthesis rate under cloudy sky was particularly associated with EC-stimulated, xanthophyll-dependent thermal dissipation of absorbed light energy. Under clear sky, a pronounced afternoon depression of CO2 assimilation rate was found in sun-adapted leaves under EC compared with AC conditions. This was caused in particular by stomata closure mediated by vapour pressure deficit.
Permanent Link: http://hdl.handle.net/11104/0243901