caa a22 4500 445890126 CHVBK 20180317145613.0 cr unu---uuuuu 170323e20110501xx s 000 0 eng 10.1007/s11120-011-9654-0 doi (NATIONALLICENCE)springer-10.1007/s11120-011-9654-0 A model for describing the light response of the nonphotochemical quenching of chlorophyll fluorescence [Elektronische Daten] [João Serôdio, Johann Lavaud] The operation of photosynthetic energy-dissipating processes is commonly characterized by measuring the light response of the nonphotochemical quenching (NPQ) of chlorophyll fluorescence, or NPQ versus E curves. This study proposes a mathematical model for the quantitative description of the generic NPQ versus E curve. The model is an adaptation of the Hill equation and is based on the close dependence of NPQ on the xanthophyll cycle (XC). The model was tested on NPQ versus E curves measured in the plant Arabidopsis thaliana and the diatom Nitzschia palea, representing the two main types of XC, the violaxanthin-antheraxanthin-zeaxanthin (VAZ) type and the diadinoxanthin-diatoxanthin (DD-DT) type, respectively. The model was also fitted to a large number of published light curves, covering the widest possible range of XC types, taxa, growth conditions, and experimental protocol of curve generation. The model provided a very good fit to experimental and published data, coping with the large variability in curve characteristics. The model was further used to quantitatively compare the light responses of NPQ and of PSII electron transport rate, ETR, through the use of indices combining parameters of the models describing the two types of light-response curves. Their application to experimental and published data showed a systematic large delay of the buildup of NPQ relatively to the saturation of photochemistry. It was found that when ETR reaches saturation, NPQ is on average still below one fifth of its maximum attainable level, which is only reached at irradiances about three times higher. It was also found that organisms having the DD-DT type of XC appeared to be able to start operating the XC at lower irradiances than those of the VAZ type. Springer Science+Business Media B.V., 2011 Chlorophyll fluorescence nationallicence Modelling nationallicence Nonphotochemical quenching nationallicence Photoacclimation nationallicence Photoprotection nationallicence Xanthophyll cycle nationallicence α : Initial slope of the ETR versus E curve nationallicence Ax : Antheraxanthin nationallicence DD : Diadinoxanthin nationallicence DT : Diatoxanthin nationallicence E : PAR irradiance (μmol m−2s−1) nationallicence E 50 : Irradiance level corresponding to 50% of NPQm in a NPQ versus E curve nationallicence E k : Light-saturation parameter of the ETR versus E curve nationallicence ETR : PSII relative electron transport rate nationallicence ETRm : Maximum ETR in a ETR versus E curve nationallicence F o, F m : Minimum and maximum fluorescence of a dark-adapted sample nationallicence F s, $$ F_{\text{m}}^{'} $$ : Steady state and maximum fluorescence of a light-adapted sample nationallicence NPQ : Nonphotochemical quenching nationallicence NPQm : Maximum NPQ value reached in a NPQ versus E curve nationallicence $$ {\text{NPQ}}_{{E_{\text{k}} }} $$ : Fraction of NPQm reached when E=E k nationallicence n : Sigmoidicity coefficient of the NPQ versus E curve nationallicence PSII : Photosystem II nationallicence RLC : Rapid light-response curve nationallicence VAZ : Vx-Ax-Zx XC nationallicence Vx : Violaxanthin nationallicence XC : Xanthophyll cycle nationallicence Zx : Zeaxanthin nationallicence Serôdio João Departamento de Biologia and CESAM—Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal aut Lavaud Johann UMR CNRS 6250 "LIENSs,” Institute for Coastal and Environmental Research (ILE), University of La Rochelle, 2 rue Olympe de Gouges, 17 000, La Rochelle, France aut Photosynthesis Research Springer Netherlands 108/1(2011-05-01), 61-76 0166-8595 108:1<61 2011 108 11120 https://doi.org/10.1007/s11120-011-9654-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-011-9654-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Serôdio João Departamento de Biologia and CESAM—Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal aut NATIONALLICENCE 700 1- Lavaud Johann UMR CNRS 6250 "LIENSs,” Institute for Coastal and Environmental Research (ILE), University of La Rochelle, 2 rue Olympe de Gouges, 17 000, La Rochelle, France aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 108/1(2011-05-01), 61-76 0166-8595 108:1<61 2011 108 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer