In vivo analysis of chlorophyll a fluorescence induction.
Quantitative characteristics of photosynthetic electron transport were evaluated in vivo on the basis of the multi-exponential analysis of OJIP fluorescence transients induced by saturating actinic light. The OJIP fluorescence curve F(t), measured in Chlamydomonas reinhardtii cells, was transformed into the (1 - F(O)/F(t)) x (F(V)/F(M))(-1) transient, which is shown to relate to PS 2 closure. We assumed that kinetics of PS 2 closure during OJIP rise reflects time-separated processes related to the establishment of redox equilibrium at the PS 2 acceptor side (OJ), PQ pool (JI), and beyond Cyt b/f (IP). Three-exponential fitting was applied to (1 - F(O)/F(t)) x (F(V)/F(M))(-1) transient to obtain lifetimes and amplitudes of the OJ, JI, and IP components of PS 2 closure, which were used to calculate overall rates of reduction and re-oxidation of the PS 2 acceptor side, PQ pool, and intermediates beyond Cyt b/f complex. The results, obtained in the presence of inhibitors, oxidative reagents, and under different stress conditions prove the suggested model and characterize the introduced parameters as useful indicators of photosynthetic function.
Antal
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T
Biological Faculty, Moscow State University, Vorobyovi Gory, 119992 Moscow, Russia. taras@biophys.msu.ru
Rubin
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A
D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000502:physiology*; D002734:Chlorophyll / Q000378:metabolism*; D000077194:Chlorophyll A; D004579:Electron Transport / Q000502:physiology*; D005453:Fluorescence; D007700:Kinetics; D008027:Light; D008954:Models, Biological; D010788:Photosynthesis / Q000502:physiology*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism
D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D013455:Sulfur; D000077194:Chlorophyll A