Kinetics of luminescence and of electron transport in photosystem II. When electron transport on acceptor side of this system is blocked

1977 ◽  
Vol 9 (2) ◽  
pp. 117-139
Author(s):  
E. M. Sorokin
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Acceptor Side ◽  
Kinetics Of

Studies about the Mechanism of Herbicidal Interaction with Photosystem II in Isolated Chloroplasts

1979 ◽  
Vol 34 (11) ◽  
pp. 1010-1014 ◽  
Author(s):  
Gernot Renger
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Excitation Energy ◽  
Electron Acceptor ◽  
Functional Organization ◽  
Regulatory Element ◽  
Release Kinetics ◽  
Acceptor Side ◽  
Receptor Sites ◽  
Isolated Chloroplasts

Abstract Based on the functional organization scheme of system-II-electron transport and its modification by different procedures a proteinaceous component enwrapping the redox components (plastoquinone molecules) of the acceptor side (thereby acting as regulatory element) is inferred to be the unique target for herbicidal interaction with system II. This proteinaceous component, which is attacked by trypsin, provides the receptor sites for the herbicides. Studies of the release kinetics in trypsinated chloroplasts of the inhibition of oxygen evolution with K3 [Fe (CN)6] as electron acceptor indicates, that there exists a binding area with different specific subreceptor sites rather than a unique binding site for the various types of inhibitors. Furthermore, trypsination of the proteinaceous component enhances the efficiency of the plastoquinone pool to act as a non-photochemical quencher for excitation energy.

The correlation between the induction kinetics of the photoacoustic signal and chlorophyll fluorescence in barley leaves is governed by changes in the redox state of the photosystem II acceptor side. A study under atmospheric and high CO2 concentrations

1997 ◽  
Vol 75 (9) ◽  
pp. 1399-1406 ◽  
Author(s):  
Nikolai G. Bukhov ◽  
Nathalie Boucher ◽  
Robert Carpentier
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Photoacoustic Signal ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Acceptor Side ◽  
Actinic Light ◽  
Induction Kinetics ◽  
Barley Leaves ◽  
Kinetics Of

The induction kinetics of chlorophyll fluorescence were measured in dark-adapted barley leaves simultaneously with O2 evolution and thermal dissipation using photoacoustic spectroscopy. Significant correlations were revealed between these parameters at low and high (about 5%) CO2 concentrations and different irradiances. In general, four phases were resolved in the induction curves of chlorophyll fluorescence or PA signals modulated at 35 Hz (O2-dependent component) or 400 Hz (thermal dissipation). During the first 10–15 s after onset of actinic light, a high level of reduction of the primary quinone acceptor of photosystem II (QA), a low magnitude of the O2-dependent photoacoustic signal, and a high level of heat production measured as the photoacoustic signal at 400 Hz were maintained. Further illumination led to a partial QA− reoxidation, an increased rate of O2 evolution, and a decline in heat production owing to an increased energy storage at the level of the plastoquinone pool. At low CO2 concentration, the steady-state level of all the above parameters was attained at the end of the first minute of illumination and remained unmodified after prolonged leaf irradiation. In contrast, the development of an additional slow peak followed by its dissipation was found for all parameters examined under high CO2 concentration and strong irradiance. The position of the slow peak in the kinetics of the O2-dependent photoacoustic signal preceded the corresponding peak of chlorophyll fluorescence measured under actinic light but coincided with the position of the peak in the kinetics of photochemical quenching. The position of the slow peak in the kinetics of thermal dissipation strictly corresponded to the one of chlorophyll fluorescence. A linear correlation was found between the magnitudes of the O2-dependent component of the photoacoustic signal and the extent of photochemical quenching. The results indicate that correlations in the kinetics and magnitudes of chlorophyll fluorescence, O2 evolution, and thermal dissipation are due at least in part to the dependence of the above parameters on the redox state of the acceptor side of photosystem II. Key words: photosynthesis, chlorophyll fluorescence, thermal dissipation, CO2, O2 evolution, plastoquinone, photoacoustic.

Picrate Salt of a Cyclic Polyether, 18-Crown-6 (Ca-picrate-18-crown-6), Inhibits the Photosynthetic Electron Transport at the Acceptor Side of Photosystem II

1998 ◽  
Vol 53 (3-4) ◽  
pp. 159-162
Author(s):  
Manoj K. Joshi ◽  
T. S. Desai ◽  
Prasanna Mohanty
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Photosynthetic Electron Transport ◽  
Acceptor Side ◽  
Site Of Action ◽  
Fast Chlorophyll A Fluorescence

Abstract It has been demonstrated that cyclic polyether, K -picrate-18-crown-6 inhibited photosyn­ thetic electron transport (Sabat et al., 1991, Z. Naturforsch. 46c , 87-92) . We further analyzed the alterations induced in the fast chlorophyll a fluorescence and thermoluminescence pattern of pea thylakoids by calcium-18-crown-6 (crown-picrate). The results indicate that the site of action of calcium crown-picrate is at the acceptor side of photosystem II.

scholarly journals Respiration Interacts With Photosynthesis Through the Acceptor Side of Photosystem I, Reflected in the Dark-to-Light Induction Kinetics of Chlorophyll Fluorescence in the Cyanobacterium Synechocystis sp. PCC 6803

2021 ◽  
Vol 12 ◽  
Author(s):  
Takako Ogawa ◽  
Kenta Suzuki ◽  
Kintake Sonoike
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Photosystem I ◽  
Fluorescence Induction ◽  
Chlorophyll Fluorescence Induction ◽  
Light Induction ◽  
Acceptor Side ◽  
Induction Kinetics ◽  
Electron Transport Chains ◽  
Kinetics Of

In cyanobacteria, the photosynthetic prokaryotes, direct interaction between photosynthesis and respiration exists at plastoquinone (PQ) pool, which is shared by the two electron transport chains. Another possible point of intersection of the two electron transport chains is NADPH, which is the major electron donor to the respiratory chain as well as the final product of the photosynthetic chain. Here, we showed that the redox state of NADPH in the dark affected chlorophyll fluorescence induction in the cyanobacterium Synechocystis sp. PCC 6803 in a quantitative manner. Accumulation of the reduced NADPH in the dark due to the defect in type 1 NAD(P)H dehydrogenase complex in the respiratory chain resulted in the faster rise to the peak in the dark-to-light induction of chlorophyll fluorescence, while depletion of NADPH due to the defect in pentose phosphate pathway resulted in the delayed appearance of the initial peak in the induction kinetics. There was a strong correlation between the dark level of NADPH determined by its fluorescence and the peak position of the induction kinetics of chlorophyll fluorescence. These results indicate that photosynthesis interacts with respiration through NADPH, which enable us to monitor the redox condition of the acceptor side of photosystem I by simple measurements of chlorophyll fluorescence induction in cyanobacteria.

Stimulatory Effects of an Ammonium Salt Biocide on Photosynthetic Electron Transport Reactions

1994 ◽  
Vol 49 (1-2) ◽  
pp. 87-94 ◽  
Author(s):  
Klaus P. Bader ◽  
Susanne Höper
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Ammonium Salt ◽  
Photosystem I ◽  
Reaction Rates ◽  
Filamentous Cyanobacterium ◽  
Relaxation Kinetics ◽  
Photosynthetic Membranes ◽  
Oscillatoria Chalybea ◽  
Kinetics Of

Alkylbenzyldimethylammonium chloride (ABDAC, zephirol) has been shown to improve the functioning of the photosynthetic apparatus of the filamentous cyanobacterium Oscillatoria chalybea (Bader, K. P. (1989) Biochim. Biophys. Acta 975, 399-402). This biocide exerts stimulatory effects on various electron transport reactions in Oscillatoria chalybea and chloroplasts from higher plants. By means of oxygen evolution measurements and of repetitive flash-induced absorption spectroscopy we were able to demonstrate an impact of the drug on the major complexes of photosynthetic membranes, i.e. the water splitting complex, photosystem II and photosystem I. Both, P820- and X320-absorption change signals were enhanced by the addition of ABDAC. Along with the quantitative analysis we investigated the relaxation kinetics of the signals and observed a substantial stabilization of the oxidized states of the respective redox components in the presence of the ammonium salt. Under appropriate conditions the relaxation kinetics of the absorption signals were significantly slowed down. ABDAC also affects photosystem I in Oscillatoria chalybea, but only under conditions, where a donor/acceptor system i.e. an isolated photosystem I reaction with photosystem II being disconnected was measured. Electron transport through the whole chain i.e. with water as the electron donor yielded no effect of the quaternary ammonium salt. It is suggested that this is due to an extremely bad linkage between the two photosystem, each of which, however, shows good reaction rates, when separately measured. The described interactions of the biocide with photosynthetic membranes are not restricted to Oscillatoria chalybea but are also observed with higher plant chloroplasts. In these systems, ABDAC enhances X320- and P700-signals to a comparable extent. In this case the P700-signal is stimulated in assays with electrons which are furnished from water which hints at good coupling between the two photosystems in our tobacco chloroplast preparations.

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