Abstract
Chlorophyll a fluorescence induction (FI) is widely used as a probe for studying photosynthesis. On illumination, fluorescence emission rises from an initial level O to a maximum P through transient steps, termed J and I. FI kinetics reflect the overall performance of photosystem II (PSII). Although FI kinetics are commonly and easily measured, there is a lack of consensus as to what controls the characteristic series of transients, partially because most of the current models of FI focus on subsets of reactions of PSII, but not the whole. Here we present a model of fluorescence induction, which includes all discrete energy and electron transfer steps in and around PSII, avoiding any assumptions about what is critical to obtaining O J I P kinetics. This model successfully simulates the observed kinetics of fluorescence induction including O J I P transients. The fluorescence emission in this model was calculated directly from the amount of excited singlet-state chlorophyll in the core and peripheral antennae of PSII. Electron and energy transfer were simulated by a series of linked differential equations. A variable step numerical integration procedure (ode15s) from MATLAB provided a computationally efficient method of solving these linked equations. This in silico representation of the complete molecular system provides an experimental workbench for testing hypotheses as to the underlying mechanism controlling the O J I P kinetics and fluorescence emission at these points. Simulations based on this model showed that J corresponds to the peak concentrations of Q −A QB (QA and QB are the first and second quinone electron acceptor of PSII respectively) and Q −A Q −B and I to the first shoulder in the increase in concentration of Q −A Q 2−B . The P peak coincides with maximum concentrations of both Q −A Q 2−B and PQH2. In addition, simulations using this model suggest that different ratios of the peripheral antenna and core antenna lead to differences in fluorescence emission at O without affecting fluorescence emission at J, I and P. An increase in the concentration of QB-nonreducing PSII centers leads to higher fluorescence emission at O and correspondingly decreases the variable to maximum fluorescence ratio (F v/F m).
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References
Baake E, Schloder JP (1992) Modeling the fast fluorescence rise of photosynthesis. Bull Math Biol 54:999–1021
Baker NR, Oxborough K (2004) Chlorophyll fluorescence as a probe of photosynthetic productivity. In: Papageorgiou GC, Govindjee (eds) Chlorophyll a fluorescence: a signature of photosynthesis. Springer, Dordrecht, pp 65–82
Baker NR, East TM, Long SP (1983) Chilling damage to photosynthesis in young Zea mays. J Exp Bot 34:189–197
Ben-Shem A, Frolow F, Nelson N (2003) Crystal structure of plant photosystem I. Nature 426:630–635
Bolhár-Nordenkampf HR, Long SP, Baker NR, Qquist G, Schreiber U, Lechner EG (1989) Chlorophyll fluorescence as a probe of the photosynthetic competence of leaves in the field—a review of current instrumentation. Funct Ecol 3:497–514
Bouges Bocquet B (1977) Cytochrome f and plastocyanin kinetics in C pyrenoidosa. Biochim Biophys Acta 462:362–370
Bowes J, Crofts AR (1980) Binary oscillations in the rate of reoxidation of the primary acceptor of photosystem II. Biochim Biophys Acta 590:373–384
Bowes J, Crofts AR, Arntzen CJ (1980) Redox reactions on the reducing side of photosystem-II in chloroplasts with altered herbicide binding-properties. Arch Biochem Biophys 200:303–308
Brettel K, Schlodder E, Witt HT (1984) Nanosecond reduction kinetics of photooxidized chlorophyll aII (P-680) in single flashes as a probe for the electron pathway, H+-release and charge accumulation in the O2-evolving complex. Biochim Biophys Acta 766:403–415
Brody SS (2002) Fluorescence lifetime, yield, energy transfer and spectrum in photosynthesis, 1950–1960. Photosynth Res 73:127–132
Butler WL (1972) On the primary nature of fluorescence yield changes associated with photosynthesis. P Natl Acad Sci USA 69:3420–3422
Chitnis PR (2001) Photosystem I: function and physiology. Annu Rev Plant Physiol Plant Mol Biol 52:593–636
Chylla RA, Whitmarsh J (1990) Light saturation response of inactive photosystem-II reaction centers in spinach. Photosynth Res 25:39–48
Crofts AR, Robinson HH, Snozzi M (1984) Reactions of quinones at catalytic sites: a diffusional role in H+ transfer. In Sybesma C (ed) Advances in photosynthesis research. volume 1. Martinus Nijhoff/Dr W Junk Publishers, The Hague, Netherlands, pp 461–468
Crofts AR, Baroli I, Kramer D, Taoka S (1993) Kinetics of electron-transfer between QA and QB in wild-type and herbicide-resistant mutants of Chlamydomonas reinhardtii. Z Naturforschung C-a J Biosci 48:259–266
Dau H (1994) Molecular mechanisms and quantitative models of variable photosystem II fluorescence. Photochem Photobiol 60:1–23
Dekker JP, Plijter JJ, Ouwehand L, van Gorkom HJ (1984) Kinetics of maganses redox transitions in the oxygen evolving complex of photosystem II. Biochim Biophys Acta 767:176–179
Delosme R (1967) Etude de l’induction de fluorescence des algues vertes et des chloroplasts au debut d’une illumination intense. Biochim Biophys Acta 143:108–128
Delosme R (1971) New results about chlorophyll fluorescence in vivo. In: Forti G, Avron M, Melandri A (eds) Proceedings of the 11th international congress on photosynthesis research. volume 1. Martinus Nijhoff/Dr W Junk, The Hague, Netherlands, pp 187–95
Deprez J, Paillotin G, Dobek A, Leibl W, Trissl HW, Breton J (1990) Competition between energy trapping and exciton annihilation in the lake model of the photosynthetic membrane of purple bacteria. Biochim Biophys Acta 1015:295–303
Diner BA (1977) Dependence of deactivation reactions of photosystem II on the redox state of the plastoquinone pool A, varied under anaerobic conditions. Equilibria on the acceptor side of photosystem II. Biochim Biophys Acta 460:247–258
Ferreira KN, Iverson TM, Maghlaoui K, Barber J, Iwata S (2004) Architecture of the photosynthetic oxygen-evolving center. Science 303:1831–1838
Forbush B, Kok B, McGloin MP (1971) Cooperation of charges in photosynthetic O2 evolution. II. Damping of flash yield oscillation and deactivation. Photochem Photobiol 14:307–321
Golbeck JH, Kok B (1979) Redox titration of electron acceptor Q and the plastoquinone pool in photosystem II. Biochim Biophys Acta 547:347–360
Govindjee (1995) Sixty -three years since Kautsky: chlorophyll a fluorescence. Aust J Plant Physiol 22:131–160
Govindjee (2004) Chlorophyll fluorescence: a bit of basics and history. In: Papageorgiou GC, Govindjee (eds) Chlorophyll a fluorescence: a signature of photosynthesis. Springer, Dordrecht, pp 1–42
van Grondelle R, Gobets B (2004) Transfer and trapping of excitation in plant photosystems. In: Papageorgiou C, Govindjee (eds) Chlorophyll fluorescence: a signature of photosynthesis. Springer, Dordrecht, pp 107–132
Guenther JE, Melis A (1990) The physiological significance of photosystem-Ii heterogeneity in chloroplasts. Photosynth Res 23:105–109
Haehnel W (1976) The reduction kinetics of chlorophyll a1 as indicator for proton uptake between light reactions in chloroplasts. Biochim Biophys Acta 440:506–521
Hankamer B, Barber J, Boekema EJ (1997) Structure and membrane organization of photosystem II in green plants. Annu Rev Plant Physiol Plant Mol Biol 48:641–671
Haumann M, Junge W (1994) Extent and rate of proton release by photosynthetic water oxidation in thylakoids: electrostatic relaxation versus chemical production. Biochemistry 33:864–872
Haumann M, Junge W (1994) The rates of proton uptake and electron-transfer at the reducing side of photosystem-II in thylakoids. FEBS Lett 347:45–50
Horton P, Ruban AV, Walters RG (1996) Regulation of light harvesting in green plants. Annu Rev Plant Physiol Plant Mol Biol 47:655–684
Joliot A, Joliot P (1964) Etude cinétique de la réaction photochimique libérant l’oxygène au cours de la photosynthèse. Comput Rend Acad Sci Paris 258:4622–4625
Joliot P, Joliot A (2003) Excitation transfer between photosynthetic units: the 1964 experiment. Photosynth Res 76:241–245
Joliot P, Lavergne J, Beal D (1992) Plastoquinone compartmentation in chloroplasts. 1 Evidence for domains with different rates of photo-reduction. Biochim Biophys Acta 1101:1–12
Kok B, Forbush B, McGloin MP (1970) Cooperation of charges in photosynthetic O2 evolution I A linear four step mechanism. Photochem Photobiol 11:457–475
Kramer DM, Dimarco G, Loreto F (1995) Contribution of plastoquinone quenching to saturation pulse-induced rise of chlorophyll fluorescence in leaves. In Mathis P (ed) Photosynthesis from light to the biospere. volume 1. Kluwer, Dordrecht, pp 147–150
Krause GH, Weis E (1991) Chlorophyll fluorescence and photosynthesis-the basics. Annu Rev Plant Physiol Plant Mol Biol 42:313–349
Laible P, Zipfel W, Owens T (1994) Excited state dynamics in chlorophyll based antennae: the rate of transfer equlibrium. Biophys J 66:844–860
Lavergne J, Briantais JM (1996) Photosystem-II heterogeneity. In: Ort DR, Yocum CF (eds) Oxygen photosynthesis: the light reactions. Kluwer, Dordrecht, pp 265–287
Lavergne J, Trissl HW (1995) Theory of fluorescence induction in photosystem II - derivation of analytical expressions in a model including exciton-radical- pair equilibrium and restricted energy transfer between photosynthetic units. Biophys J 68:2474–2492
Lazar D (1999) Chlorophyll a fluorescence induction. Biochim Biophys Acta 1412:1–28
Lazar D (2003) Chlorophyll a fluorescence rise induced by high light illumination of dark-adapted plant tissue studied by means of a model of photosystem II and considering photosystem II heterogeneity. J Theor Biol 220:469–503
Lazar D, Pospisil P (1999) Mathematical simulation of chlorophyll a fluorescence rise measured with 3-(3′, 4′-dichlorophenyl)-1,1-dimethylure barley leaves at room and high temperatures. Eur Biophys J 28:468–477
Lazar D, Naus J, Matouskova M, Flasarova M (1997) Mathematical modeling of changes in chlorophyll fluorescence induction caused by herbicides. Pestic Biochem Physiol 57:200–210
Lazar D, Brokes M, Naus J, Dvorak L (1998) Mathematical modelling of 3-(3′, 4′-dichlorophenyl)-1,1-dimethylurea action in plant leaves. J Theor Biol 191:79–86
Lebedeva GV, Belyaeva NE, Demin OV, Riznichenko GY, Rubin AB (2002) Kinetic model of primary photosynthetic processes in chloroplasts description of the fast phase of chlorophyll fluorescence induction under different light intensities. Biophysics 47:968–980
Liu ZF, Yan HC, Wang KB, Kuang TY, Zhang JP, Gui LL, An XM, Chang WR (2004) Crystal structure of spinach major light-harvesting complex at 2.72 angstrom resolution. Nature 428:287–292
Long SP, Postl WF, Bolhár-Nordenkampf HR (1993) Quantum yields for uptake of carbon dioxide in C3 vascular plants of contrasting habitats and taxonomic groupings. Planta 189:226–234
Long SP, Humphries SW, Falkowski PG (1994) Photoinhibition of photosynthesis in nature. Ann Rev Plant Physiol Mol Biol 45:633–662
Melis A (1991) Dynamics of photosynthetic membrane-composition and function. Biochim Biophys Acta 1058:87–106
Messinger J, Renger G (1993) Generation, oxidation by the oxidized form of the tyrosine of polypeptide D2, and possible electronic configuration of the redox states S0, S1 and S2 of the water oxidase in isolated spinach thylakoids. Biochemistry 32:9379–9386
Meunier PC (1993) Oxygen evolution by photosystem II - the contribution of backward transitions to the anomalous behavior of double-hits revealed by a new analysis method. Photosynth Res 36:111–118
Meunier PC, Burnap RL, Sherman LA (1996) Improved 5-step modeling of the Photosystem II S-state mechanism in cyanobacteria. Photosynth Res 47:61–76
Meyer B, Schlodder E, Dekker JP, Witt HT (1989) O2 evolution and Chl a II+ (P +680 ) nanosecond reduction kinetics in single flashes as a function of pH. Biochim Biophys Acta 974:36–43
Mitchell R, Spillmann A, Haehnel W (1990) Plastoquinol diffusion in linear photosynthetic electron-transport. Biophys J 58:1011–1024
Neubauer C, Schreiber U (1987) The polyphasic rise of chlorophyll fluorescence upon onset of strong continous illumination: I Saturation charactristics and partial control by photosystem II acceptor side. Zeitschrift für Naturforschung 42c:1426–1254
Niyogi KK (1999) Photoprotection revisited: genetic and molecular approaches. Ann Plant Physiol Plant Mol Biol 50:333–359
Packham NK, Hodges M, Etienne AL, Briantais JM (1988) Changes in the flash-induced oxygen yield pattern by thylakoid membrane phosphorylation. Photosynth Res 15:221–232
Peter GF, Thornber JP (1991) Biochemical composition and organization of higher plant photosystem II light harvesting pigment proteins. J Biol Chem 266:16745–16754
Quigg A, Beardall J, Wydrzynski T (2003) Photoacclimation involves modulation of the photosynthetic oxygen-evolving reactions in Dunaliella tertiolecta and Phaeodactylum tricornutum. Funct Plant Biol 30:301–308
Robinson HH, Crofts AR (1983) Kinetics of the oxidation-reduction reactions of the photosystem II quinone acceptor complex, and teh pathway for deactivation. FEBS Lett 153:221–226
Roelofs TA, Lee CH, Holzwarth AR (1992) Global target analysis of picosecond chlorophyll fluorescence kinetics from pea chloroplasts-a new approach to the characterization of the primary processes in photosystem II α units and β units. Biophys J 61:1147–1163
Rohacek K, Bartak M (1999) Technique of the modulated chlorophyll fluorescence: basic concepts, useful parameters, and some applications. Photosynthetica 37:339–363
Rutherford W, Govindjee, Inoue Y (1984) Charge accumulation and photochemistry in leaves studied by thermoluminescence and delayed light emission. P Natl Acad Sci USA 81:1107–1111
Sayed OH (2003) Chlorophyll fluorescence as a tool in cereal crop research. Photosynthetica 41:321–330
Schatz GH, Brock H, Holzwarth AR (1987) Picosecond kinetics of fluorescence and absorbency changes in photosystem II particles excited at low photon density. P Natl Acad Sci USA 84:8414–8418
Schatz GH, Brock H, Holzwarth AR (1988) Kinetics and energetic model for the primary processes in photosystem II. Biophys J 54:397–405
Schreiber U, Krieger A (1996) Two fundermentally different types of variable chlorophyll fluorescence in vivo. FEBS Lett 397:131–135
Shampine LF, Reichelt MW (1997) The MATLAB ODE suite. SIAM J Sci Comp 18:1–22
Shinkarev VP (2005) Flash-induced oxygen evolution in photosynthesis: simple solution for the extended S-state model that includes misses, double-hits, inactivation, and backward-transitions. Biophys J 88:412–421
Sonneveld A, Rademaker H, Duysens LNM (1979) Chlorophyll a fluorescence as a monitor of nanosecond reduction of the photooxidized primary donor P +680 of photosystem II. Biochim Biophys Acta 548:536–551
Stirbet A, Strasser RJ (2001) The possible role of pheophytine in the fast fluorescence risk OKJIP. In: Proceedings of the 12th international congress on photosynthesis (CD-ROM), S11–027, CSIRO Publishing, Collingwood
Stirbet A, Govindjee, Strasser BJ, Strasser R (1998) Chlorophyll a fluorescence induction in higher plants: modelling and numerical simulation. J Theor Biol 193:131–151
Strasser RJ, Srivastava A, Govindjee (1995) Polyphasic chlorophyll a fluorescence transient in plants and cyanobacteria. Photochem Photobiol 61:32–42
Strasser RJ, Tsimilli-Michael M, Srivastava A (2004) Analysis of chlorophyll a fluorescence transient. In: Papageorgiou GC, Govindjee (eds) Chlorophyll a fluorescence: a signature of photosynthesis. Springer, Dordrecht, pp 321–362
Trissl HW, Lavergne J (1995) Fluorescence induction from photosystem II - analytical equations for the yields of photochemistry and fluorescence derived from analysis of a model including exciton-radical pair equilibrium and restricted energy-transfer between photosynthetic units. Aust J Plant Physiol 22:183–193
Trissl HW, Gao Y, Wulf K (1993) Theoretical fluorescence induction curves derived from coupled differential equations describing the primary photochemistry of photosystem II by an exciton radical pair equilibrium. Biophys J 64:974–988
Vavilin DV, Tyystjarvi E, Aro EM (1998) Model for the fluorescence induction curve of photoinhibited thylakoids. Biophys J 75:503–512
Vermeglio A (1977) Secondary electron transfer in reaction centers of Rhodopseudomonas sphaeroides: out-of-phase periodicity of two for the formation of ubisemiquinone and fully reduced ubiquinone. Biochim Biophys Acta 459:516–524
Vernotte C, Etienne AL, Briantais JM (1979) Quenching of the system II chlorophyll fluorescence by the plastoquinone pool. Biochim Biophys Acta 545:519–527
Vredenberg WJ (2000) A three-state model for energy trapping and chlorophyll fluorescence in photosystem II incorporating radical pair recombination. Biophys J 79:26–38
Vredenberg WJ (2004) System analysis of photoeletrochemical control of chlorophyll fluorescence in terms of trapping models of Photosystem II: a challenging view. In: Papageorgiou GC, Govindjee (eds) Chlorophyll a fluorescence: a signature of photosynthesis. Springer, Dordrecht, pp 133–172
Whitmarsh J, Bowyer JR, Crofts AR (1982) Modification of the apparent redox reaction between cytochrome-F and the rieske iron-sulfur protein. Biochim Biophys Acta 682:404–412
Wraight CA (1977) Electron acceptors of photosynthetic bacterial reaction centers Direct observation of oscillatory behavior suggesting two closely equivalent ubiquinones. Biochim Biophys Acta 459:525–531
Zhu X-G (2004) Computational approaches to guiding biotechnological improvement of crop photosynthetic efficiency. Ph D thesis, the University of Illinois. Urbana, IL
Zhu X-G, Ort DR, Whitmarsh J, Long SP (2004) The slow reversibility of photosystem II thermal energy dissipation on transfer from high to low light may cause large losses in carbon gain by crop canopies A theoretical analysis. J Exp Bot 55:1167–1175
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This work was co-supported by the National Center for Supercomputing Applications, and the U. S. National Science Foundation IBN 04-17126.
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Appendices
Appendix 1
The ordinary differential equations representing the model of fluorescence induction (Fig. 1). This set of equations only includes the differential equations representing the change of concentrations of components associated with QB-reducing PSII reaction centers. Same set of different equations were used to describe the concentration changes of components associated with QB-nonreducing PSII reaction centers. The QB-nonreducing and QB-reducing reaction centers were assumed to share the same plastoquinol pool. The differential equation for [PQH2] in the full model combines the contributions from reactions associated with both QB-reducing and QB-nonreducing reaction centers. The rate equation for each velocity variable is listed in Appendix 2. The abbreviations of reaction velocities used in the system of differential equations are defined in Appendix 3.
Appendix 2
The rate equations describing the reactions associated with QB-reducing reaction centers used in the model of fluorescence induction. The set of equations for the reactions associated with the QB-nonreducing reaction centers were similar to this set and not listed. See Appendix 3 for definition of abbreviations. The details for derivation of each rate equations are in the main text. The detailed description for each abbreviation is listed in Appendix 3 except that the rate constants are listed in Table 1.
Appendix 3
Definitions of all abbreviations except rate constants used in the model
Abbrev. | Description | Unit |
---|---|---|
[Ap] | Concentration of excitation energy on peripheral antenna of photosystem II | μmol m−2 |
[P *680 Pheo] | The concentration of excited P680 associated with Pheo | μmol m−2 |
[P +680 Pheo] | The concentration of P +680 associated with Pheo | μmol m−2 |
[P +680 Pheo−] | The concentration of P +680 associated with Pheo− | μmol m−2 |
[P680Pheo] | The concentration of P680 associated with Pheo | μmol m−2 |
[P680Pheo−] | The concentration of P680 associated with Pheo− | μmol m−2 |
[P680PheoT] | The total concentration of P680Pheo, P +680 Pheo, P680Pheo− and P +680 Pheo− . | μmol m−2 |
[PQ] | The concentration of plastoquinone | μmol m−2 |
[PQ] | The concentration of oxidized plastoquinone | μmol m−2 |
[PQH2] | The concentration of fully reduced plastoquinone | μmol m−2 |
[PQT] | The total concentration of plastoquinone and plastoquinol in thylakoid membrane | μmol m−2 |
[QA] | The concentration of oxidized QA | μmol m−2 |
[Q −A ] | The concentration of reduced QA | μmol m−2 |
[QAQB] | The concentration of oxidized QA associated with oxidized QB | μmol m−2 |
[Q −A QB] | The concentration of reduced QA associated with oxidized QB | μmol m−2 |
[Q −A QB] | The concentration of reduced QA associated with Q −B | μmol m−2 |
[Q −A QB] | The concentration of reduced QA associated with Q 2−B | μmol m−2 |
[QAQ −B ] | The concentration of oxidized QA associated with Q −B | μmol m−2 |
[QAQ 2−B ] | The concentration of oxidized QA associated with Q 2−B | μmol m−2 |
[S n] | The concentration of oxygen evolving complex at S n state | μmol m−2 |
[S nT ] | The concentration of oxygen evolving complex at S n state before donating electron to tyrosine (Y z) | μmol m−2 |
[S nTp ] | The concentration of oxygen evolving complex at S n state after donating electron to tyrosine (Y z) | μmol m−2 |
[U] | Concentration of excitation energy on core antenna of QB-reducing photosystem II | μmol m−2 |
[Ui] | Concentration of excitation energy on core antenna of QB-nonreducing photosystem II | μmol m−2 |
[Uifc] | The concentration of excitation energy on chlorophylls detached from core antenna of QB-nonreducing photosystem II | μmol m−2 |
[Y Z] | The concentration of primary electron donor for reaction center of PSII (P680) | μmol m−2 |
Ai | Incident photon flux density on peripheral antenna of QB-nonreducing photosystem II | μmol m−2 s−1 |
AiP | The concentration of excitation energy on peripheral antenna of QB-nonreducing photosystem II | μmol m−2 |
I a | The incident photon flux density on peripheral PSII antenna | μmol m−2 s−1 |
I c | The incident photon flux density on core antenna of QB-reducing reaction center | μmol m−2 s−1 |
I in | The total incident photon flux density | μmol m−2 s−1 |
n | The ratio of PSI to PSII | NA |
P680 | The reaction center chlorophyll of PSII. It can exist in native state (P680), excited state (P *680 ), or oxidized state (P +680 ). | NA |
Pheo | Pheophytin, the first electron acceptor of primary charge separation in PSII. It can exist in either native state (Pheo) or reduced state (Pheo−). | NA |
q | The proportion of oxidized QA | NA |
QA | The first quinine electron acceptor of PSII | NA |
QB | The second quinine electron acceptor of PSII | NA |
Uif | Incident photon flux density on chlorophylls detached from core antenna of QB-nonreducing photosystem II | μmol m−2 s−1 |
v_pq_ox | The rate of PQH2 oxidation by Cyt b6f | μmol m−2 s−1 |
v_r3 | The rate of the exchange of PQH2 with QB associated with QA | μmol m−2 s−1 |
v_r3_n | The rate of exchange of PQH2 with QB associated with Q −A | μmol m−2 s−1 |
v 1 | The rate of charge separation in the QB-reducing PSII reaction center | μmol m−2 s−1 |
v −1 | The rate of charge recombination in the QB-reducing PSII reaction center | μmol m−2 s−1 |
v2_0m_n | The rate of reactions relating to electron transfer from Pheo− to QA where m represents the redox state of QB with 0 for QB, 1 for Q −B and 2 for Q 2−B , and n represents the redox state of P680 with 1 for P +680 and 2 for P680, e.g. v2_00_1: the rate of reduction of QAQB by P +680 Pheo− | μmol m−2 s−1 |
v 2_1 | The rate of QAreduction by P +680 Pheo− | μmol m−2 s−1 |
v 2_2 | The rate of QAreduction by P680Pheo− | μmol m−2 s−1 |
v3 | The rate of exchange of PQ with Q 2−B associated with QA | μmol m−2 s−1 |
v3_n | The rate of exchange of PQ with Q 2−B associated with Q −A | μmol m−2 s−1 |
vAB1 | The rate of electron transfer from Q −A to QB | μmol m−2 s−1 |
vAB2 | The rate of electron transfer from Q −A to Q −B | μmol m−2 s−1 |
v Ad | The rate of heat dissipation from the peripheral antenna | μmol m−2 s−1 |
v Af | The rate of fluorescence emission from the peripheral antenna | μmol m−2 s−1 |
v AU | The rate of excitation energy transfer from peripheral to core antenna | μmol m−2 s−1 |
vBA1 | The rate of electron transfer from Q −B to QA | μmol m−2 s−1 |
vBA2 | The rate of electron transfer from Q −2B to QA | μmol m−2 s−1 |
v nz | The rate of oxidation of Sn state of oxygen evolution complex | μmol m−2 s−1 |
v nz_1 | The rate of electron transfer from oxygen evolution complex at Sn state to P +680 associated with Pheo− via Yz | μmol m−2 s−1 |
v nz_2 | The rate of electron transfer from oxygen evolution complex at Sn state to P +680 associated with Pheo via Yz | μmol m−2 s−1 |
v P680qA | The rate of quenching of excitation energy in the peripheral antenna by P +680 | μmol m−2 s−1 |
v P680qU | The rate of quenching of excitation energy in the core antenna by P +680 | μmol m−2 s−1 |
v PQqA | The rate of quenching of excitation energy in the peripheral antenna by oxidized plastoquinone | μmol m−2 s−1 |
v PQqU | The rate of quenching of excitation energy in the core antenna by oxidized plastoquinone | μmol m−2 s−1 |
vr2_0m_n | The back reaction of v2_0m_n, see v2_0m_n for details | μmol m−2 s−1 |
v r2_1 | The rate of Q −A oxidation by P +680 Pheo | μmol m−2 s−1 |
v r2_2 | The rate of Q −A oxidation by P680Pheo | μmol m−2 s−1 |
vsm_sn | The rate of transition from S m state to S n state of oxygen evolution complex | μmol m−2 s−1 |
v UA | The rate of excitation energy transfer from core antenna to peripheral antenna | μmol m−2 s−1 |
v Ud | The rate of heat dissipation of excitation energy from the core antenna of QB-reducing PSII reaction center | μmol m−2 s−1 |
v Uf | The rate of fluorescence emission from the core antenna of QB-reducing reaction center | μmol m−2 s−1 |
v z_1 | The rate of P +680 Pheo− reduction | μmol m−2 s−1 |
v z_2 | The rate of P +680 Pheo reduction | μmol m−2 s−1 |
x | The ratio of the concentration of QB-nonreducing PSII reaction center to that of QB-reducing reaction center | NA |
Φf | Fluorescence yield | μmol m−2 s−1 |
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Zhu, XG., Govindjee, ., Baker, N.R. et al. Chlorophyll a fluorescence induction kinetics in leaves predicted from a model describing each discrete step of excitation energy and electron transfer associated with Photosystem II. Planta 223, 114–133 (2005). https://doi.org/10.1007/s00425-005-0064-4
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DOI: https://doi.org/10.1007/s00425-005-0064-4