Thylakoid membrane model of the Chl a fluorescence transient and P700 induction kinetics in plant leaves

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• 作者：N. E. Belyaeva ; A. A. Bulychev ; G. Yu Riznichenko ; A. B. Rubin
• 关键词：Chlorophyll a fluorescence yield ; Cytochrome b6f complex ; Dissipative energy losses ; Electron transfer ; Model simulation ; Photosynthetic induction ; Photosystems I and II ; Proton transfer ; Transmembrane charge fluxes
• 刊名：Photosynthesis Research
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：130
• 期：1-3
• 页码：491-515
• 全文大小：2,728 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Plant Physiology
  
• 出版者：Springer Netherlands
• ISSN：1573-5079
• 卷排序：130

文摘

A new Thylakoid model is presented, which describes in detail the electron/proton transfer reactions between membrane protein complexes including photosystems II and I (PSII, PSI), cytochrome (Cyt) b₆f, mobile plastoquinone PQ pool in the thylakoid membrane, plastocyanin in lumen and ferredoxin in stroma, reduction of NADP via FNR and cyclic electron transfer. The Thylakoid model parameters were fitted both to Chl fluorescence induction data (FI) and oxido-reductions of P700 (ΔA₈₁₀) measured from 20 μs up to 20 s in pea leaves. The two-wave kinetics of FI and ΔA₈₁₀ (O(JI)PSM and OABCDE) were described quantitatively, provided that the values of membrane electrochemical potential components ΔΨ(t), pH_L(t)/pH_S(t) are in physiologically relevant ranges. The time courses on the time scale from nanoseconds to tens of seconds of oxido-reduction changes of ET components as well as concentrations of proton/ions (K+, Cl−) were calculated. We assume a low constant FNR activity over this period. Charge movements across the thylakoid membrane by passive leakage and active ATPase transport and proton buffer reactions are simulated. The dynamics of charge fluxes during photosynthetic induction under low light (PFD 200 μmol photons m−2 s−1) were analyzed. The initial wave of P700 oxidation within 20 ms during independent operation of PSI and PSII was followed after 50 ms by PSI donor-side reduction from reduced PQ pool via Cyt b₆f site. The Cyt b₆f reactions contribute to the stabilization of fluxes in the time range 1 s < t < 10 s. The detailed analysis of Chl a fluorescence at the PSM stage (t > 10 s) would need the investigation of FNR activation effect in order to explain the transitions between cyclic and linear electron transport.