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Delayed fluorescence emitted from light harvesting complex II and photosystem II of higher plants in the 100 ns–5 μs time domain
Author(s) -
Christen G.,
Steffen R.,
Renger G.
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01641-0
Subject(s) - p680 , quantum yield , thylakoid , photosystem ii , fluorescence , chemistry , excited state , analytical chemistry (journal) , phosphorescence , kinetics , chlorophyll fluorescence , photochemistry , biophysics , physics , atomic physics , photosystem i , photosynthesis , optics , chloroplast , biology , chromatography , biochemistry , quantum mechanics , gene
This study presents the first report on delayed fluorescence (DF) emitted from spinach thylakoids, D1/D2/Cyt b ‐559 preparations and solubilized light harvesting complex II (LHCII) in the ns time domain after excitation with saturating laser flashes. The use of a new commercially available multichannel plate with rapid gating permitted a sufficient suppression of detector distortions due to the strong prompt fluorescence. The following results were obtained: (a) in dark‐adapted thylakoids, the DF amplitudes at 100 ns and 5 μs after each flash of a train of saturating actinic pulses exhibit characteristic period four oscillations of opposite sign: the DF amplitudes at 100 ns oscillate in the same manner as the quantum yield of prompt fluorescence, whereas those at 5 μs resemble the oscillation of the μs kinetics of P680 + reduction in samples with an intact water oxidizing complex, (b) the quantum yield of total DF emission in the range up to a few μs is estimated to be <10 −4 for thylakoids, (c) the DF of D1/D2/Cyt b ‐559 exhibits a monophasic decay with τ ≈50 ns, (d) DF emission is also observed in isolated LHCII with biphasic decay kinetics characterized by τ values of 65 ns and about 800 ns, (e) in contrast to thylakoids, the amplitudes of DF in D1/D2/Cyt b ‐559 preparations and solubilized LHCII do not exhibit any oscillation pattern and (f) all spectra of DF from the different sample types are characteristic for emission from the lowest excited singlet state of chlorophyll a . The implications of these findings and problems to be addressed in future research are briefly discussed.