caa a22 4500 445890010 CHVBK 20180317145613.0 cr unu---uuuuu 170323e20111201xx s 000 0 eng 10.1007/s11120-011-9709-2 doi (NATIONALLICENCE)springer-10.1007/s11120-011-9709-2 Photoacclimation in Dunaliella tertiolecta reveals a unique NPQ pattern upon exposure to irradiance [Elektronische Daten] [Sven Ihnken, Jacco Kromkamp, John Beardall] Highly time-resolved photoacclimation patterns of the chlorophyte microalga Dunaliella tertiolecta during exposure to an off-on-off (block) light pattern of saturating photon flux, and to a regime of consecutive increasing light intensities are presented. Non-photochemical quenching (NPQ) mechanisms unexpectedly responded with an initial decrease during dark-light transitions. NPQ values started to rise after light exposure of approximately 4min. State-transitions, measured as a change of PSII:PSI fluorescence emission at 77K, did not contribute to early NPQ oscillations. Addition of the uncoupler CCCP, however, caused a rapid increase in fluorescence and showed the significance of qE for NPQ. Partitioning of the quantum efficiencies showed that constitutive NPQ was (a) higher than qE-driven NPQ and (b) responded to light treatment within seconds, suggesting an active role of constitutive NPQ in variable energy dissipation, although it is thought to contribute statically to NPQ. The PSII connectivity parameter p correlated well with F′, F m ′ and NPQ during the early phase of the dark-light transients in sub-saturating light, suggesting a plastic energy distribution pattern within energetically connected PSII centres. In consecutive increasing photon flux experiments, correlations were weaker during the second light increment. Changes in connectivity can present an early photoresponse that are reflected in fluorescence signals and NPQ and might be responsive to the short-term acclimation state, and/or to the actinic photon flux. The Author(s), 2011 Connectivity nationallicence Constitutive NPQ nationallicence FRRF nationallicence Light acclimation nationallicence NPQ nationallicence qE nationallicence Photosynthesis nationallicence Chlorophyll a fluorescence nationallicence CCCP : Carbonyl cyanide 3-chlorophenylhydrazone nationallicence DCMU : 3-(3,4-Dichlorophenyl)-1,1-dimethyl urea nationallicence NPQ : Non-photochemical quenching ((F m −F m ′)/F m ′) nationallicence qE : Energy-dependent fluorescence quenching nationallicence qI : Photoinhibitory-induced fluorescence quenching nationallicence qP : Photochemical fluorescence quenching nationallicence qT : State-transition-caused fluorescence quenching nationallicence PF : Photon flux nationallicence σPSII : Functional absorption cross section of PSII in the dark nationallicence σPSII′ : Functional absorption cross section of PSII in actinic light nationallicence PSII : Photosystem II nationallicence ΔpH gradient : Trans-thylakoid pH gradient nationallicence Ihnken Sven School of Biological Sciences, Monash University, 3800, Clayton, VIC, Australia aut Kromkamp Jacco Netherlands Institute of Ecology, Centre for Estuarine and Marine Ecology (NIOO-CEME), P.O. Box 140, 4400 AC, Yerseke, The Netherlands aut Beardall John School of Biological Sciences, Monash University, 3800, Clayton, VIC, Australia aut Photosynthesis Research Springer Netherlands 110/2(2011-12-01), 123-137 0166-8595 110:2<123 2011 110 11120 https://doi.org/10.1007/s11120-011-9709-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-011-9709-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ihnken Sven School of Biological Sciences, Monash University, 3800, Clayton, VIC, Australia aut NATIONALLICENCE 700 1- Kromkamp Jacco Netherlands Institute of Ecology, Centre for Estuarine and Marine Ecology (NIOO-CEME), P.O. Box 140, 4400 AC, Yerseke, The Netherlands aut NATIONALLICENCE 700 1- Beardall John School of Biological Sciences, Monash University, 3800, Clayton, VIC, Australia aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 110/2(2011-12-01), 123-137 0166-8595 110:2<123 2011 110 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer