2015. This article is published with open access at brb3.242 Springerlink.comAbstract Paper describes principles and dar.12119 application of a novel routine that enables the quantitative analysis on the photochemical O phase of the variable fluorescence Fv related with all the reversible photo-reduction in the secondary electron acceptor QA of photosystem II (PSII) in algae and intact leaves. The kinetic parameters that determine the variable fluorescence FPP(t) related together with the release of photochemical quenching are estimated from ten ls timeresolved light-on and light-off responses of Fv induced by two subsequent light pulses of 0.25 (default) and 1000 ms duration, respectively. Application of these pulses permits estimations of (i) the actual worth in the price constants kL and kAB from the light excitation (photoreduction of QA) and with the dark re-oxidation of photoreduced QA (Q?), respectively, (ii) A the actual maximal normalized variable fluorescence [nFv] associated with one hundred photoreduction of QA of open RCs, and (iii) the actual size b of RCs in which the re-oxidation of Q?is largely suppressed (QB-nonreducing RC with a kAB * 0). The rate constants from the dark reversion of Fv connected using the release of photo-electrochemical quenching FPE and photo-electric stimulation FCET inside the successive J and I parts on the thermal phase are inside the selection of (one hundred ms)-1 and (1 s)-1, respectively. The kineticsof fluorescence changes in the course of and soon after the I phase are offered specific interest in relation to the hypothesis around the involvement of a DlH?-dependent impact in the course of this phase and thereafter. Paper closes with author’s individual view around the demands that should be fulfilled for chlorophyll fluorescence solutions becoming a right and unchallenged signature of photosynthesis in algae and plants. Key phrases Chlorophyll fluorescence kinetics ?Quenching mechanisms ?Method analysis ?TSTM ?OJIP ?Views Abbreviations ?Fraction of Qb-nonreducing RCs DlH Transmembrane proton motive force DCMU 3(3,4-Dichlorophenyl)-1,1-dimethylurea dsq Donor side quenching FPE(t) Fluorescence emission at time t, relative to Fo, exclusively related with release of photoelectrochemical quenching FPP(t) Fluorescence emission at time t, relative to Fo, exclusively connected with release of photochemical quenching FCET(t) Fluorescence emission at time t, relative to Fo, exclusively related with photo-electric stimulation F0 Fluorescence level of dark-adapted program with 100 open RCs Fm Fluorescence degree of dark-adapted system with one hundred closed RCs following fluorescence saturating pulse excitation STF P?Fluorescence level just after excitation with STF or Fm SP, respectively of technique in dark-adapted state PP Fluorescence level with 100 semi-closed RCs Fm following release of photochemical quenchingThis publication marks the 50th anniversary of author’s Ph.D. and– thesis on 26 May possibly 1965 at the University of Leiden (the Netherlands). W. GSK0660 price vredenberg Department of Plant Physiology, Wageningen University and Analysis, Wageningen, The Netherlands W. Vredenberg ( ) Division of Plant Physiology, Wageningen University and Study, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands e-mail: [email protected] FssPhotosynth Res (2015) 124:87?FIA kAB k2ABkL kqbfk-qbfkIP k-IP nFvOEC Ph(e) PSII QA QB qdsq RC SP sSP STF TSTM YZSteady state value in the light from the variable fluorescence connected exclusively with key photochemical quenching Fluorescence induction algorithm Rate continuous of Q.