Acclimation of Photosystem 2 Function of Norway Spruce Induced during First Season under Elevated CO2 in Lamellar Domes

摘要: Since July 28th, 1997 the two experimental mini-stands of young Norway spruce [Picea abies (L.) Karst.] have been grown in lamellar domes at ambient (AC) and elevated concentrations CO2 [EC, i.e., + 350 µmol(CO2) mol−1]. Before start exposure to EC (June 1997) dependencies photosystem 2 (PS2) quantum yield (Y) on irradiance, estimating efficiency PPFD utilisation PS2 photochemistry, were same for AC shoots. After one month simulation (August 1997), Y values higher needles as compared with ones (by 1–42 %), whereas months later (October an opposite effect was observed (decrease by from 1 33 %). By chlorophyll a (Chl a) fluorescence induction effects function further characterised. During first moderate improvement estimated slightly potential photochemistry (FV/FM, %) reduced amount inactive reaction centres (relative Fp1 level, 15 However, prolonged led firstly slight but significant decrease FV/FM 3 secondly reduction half time rise (t1/2, 14 finally pronounced accumulation 41 From gradual response individual Chl parameters we suggest probable sequence events determining stimulation subsequent depression during season under EC.