PS II model-based simulations of single turnover flash-induced transients of fluorescence yield monitored within the time domain of 100 ns–10 s on dark-adapted Chlorella pyrenoidosa cells

Abstract

The set up described in Steffen et al. (Biochemistry 40:173-180, 2001) was used to monitor in the time domain from 100 ns to 10 s single turnover flash-induced transients of the normalized fluorescence yield (SFITFY) on dark-adapted cells of the thermophilic algae Chlorella pyrenoidosa Chick. Perfect data fit was achieved within the framework of a previously proposed model for the PS II reaction pattern (Lebedeva et al., Biophysics 47:968-980, 2002; Belyaeva et al., Biophysics 51:860-872, 2006) after its modification by taking into account nonradiative decay processes including nonphotochemical quenching due to time-dependent populations of P680(+*) and (3)Car. On the basis of data reported in the literature, a consistent set of rate constants was obtained for electron transfer at the donor and acceptor sides of PS II, pH in lumen and stroma, the initial redox state of plastoquinone pool and the rate of plastoquinone oxidation. The evaluation of the rate constant values of dissipative processes due to quenching by carotenoid triplets in antennae and P680(+*)Q(A)(-*) recombination as well as the initial state populations after excitation with a single laser flash are close to that outlined in (Steffen et al., Biochemistry 44:3123-3133, 2005a). The simulations based on the model of the PS II reaction pattern provide information on the time courses of population probabilities of different PS II states. We analyzed the maximum (F(m)(STF)) and minimum (F(0)) of the normalized FL yield dependence on the rate of the recombination processes (radiative and dissipative nonradiative) and of P680(+*) reduction. The developed PS II model provides a basis for theoretical comparative analyses of time-dependent fluorescence signals, observed at different photosynthetic samples under various conditions (e.g. presence of herbicides, other stress conditions, excitation with actinic pulses of different intensity, and duration).

A kinetic model of rapidly reversible nonphotochemical quenching

“…Although there are numerous models of chlorophyll fluorescence kinetics (24)(25)(26), the lumen (27), entire thylakoids (28), and zeaxanthin-dependent NPQ (29), we are not aware of any models simulate the kinetics of the appearance and disappearance of qE at low and high light intensities. Simulating qE in both low and high light intensities is necessary for quantifying the benefit that qE confers to plants in fluctuating light conditions.…”

In Silico Analysis of the Regulation of the Photosynthetic Electron Transport Chain in C3 Plants

“…The equilibrium coefficients of the redox reactions within PSII are adjusted by DC, using the electrogenicities from Belyaeva et al (Belyaeva et al, 2008). The model takes into account the spectral composition of the light source by including the leaf absorptance spectrum as well as the relative efficiency of different wavelengths in driving photosynthesis (McCree, 1972).…”

Dynamic photosynthesis under a fluctuating environment: a modelling-based analysis

“…Several models of PSII kinetics have been published in recent years (Lebedeva et al, 2002;Lazár, 2003;Zhu et al, 2005;Belyaeva et al, 2008;Laisk et al, 2009b;Zaks et al, 2012;Loriaux et al, 2013;Xin et al, 2013;Zhu et al, 2013). These models differ in their degree of detail, with the most comprehensive description achieved by the model by Xin et al (2013), who use a Monte Carlo kinetic approach to integrate the master equation.…”

“…Because charge separation results in the transport of a charge orthogonal to the thylakoid membrane surface, the free energy of this reaction is affected by the existence of an electrical field (Δ{) across the thylakoid membrane (Lebedeva et al, 2002). The effect is calculated based on the electrogenicity of the reaction using coefficients calculated by Belyaeva et al (2008). Pheo reduces QA in a reversible reaction which is also affected by the electrical field across the thylakoid membrane.…”

“…The intermediate state (Q « , ) is bound very tightly to the site (Crofts and Wraight, 1983), such that only Q « and Q « +, are exchanged with the free pool of PQ and PQH2. The reductions of QB and Q « , are reversible and also affected by the existence of an electrical field across the thylakoid membrane (Belyaeva et al, 2008). The rate constants of QB and Q « , reduction were set to 5.0×10 3 s −1 and 2.0×10 3 s −1 , based on measurements by de Wijn and van Gorkom (2001), and are within the range of values reported in the literature for these parameters (2.5×10 3 -5.0×10 3 s −1 and 1.2×10 3 -3.3×10 3 s −1 , respectively (Lazár, 1999)).…”