Sigmoidal reduction kinetics of the photosystem II acceptor side in intact photosynthetic materials during fluorescence induction

2009 ◽  
Vol 8 (2) ◽  
pp. 167-173 ◽  
Author(s):  
David Joly ◽  
Robert Carpentier
Keyword(s):  
Photosystem Ii ◽  
Fluorescence Induction ◽  
Reduction Kinetics ◽  
Acceptor Side ◽  
Kinetics Of

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.

Variable Fluorescence and Fluorescence Spectra of Algae after Herbicide-Induced Pigment Bleaching

1983 ◽  
Vol 38 (7-8) ◽  
pp. 556-562 ◽  
Author(s):  
Navassard V. Karapetyan ◽  
Reto Strasser ◽  
Peter Boger
Keyword(s):  
Photosystem Ii ◽  
Fluorescence Spectra ◽  
Chlorophyll Biosynthesis ◽  
Fluorescence Induction ◽  
Reaction Centers ◽  
The State ◽  
Variable Fluorescence ◽  
Acceptor Side ◽  
Slow Decay ◽  
Chlorophyll Bleaching

Herbicides like norflurazon, oxadiazon, or oxyfluorfen affect the pigment apparatus of green algae. Their influence on variable (FmaK - F0) and initial fluorescence (F0) as well as on the state of chlorophylls were investigated. Two main modes of action of these herbicides on the photo­synthetic apparatus during growth have been found:First: Scenedesmus cells grown with norflurazon. a carotene-biosynthesis inhibitor, show chlorophyll bleaching concurrently with decrease or inactivation of photosystem-II reaction centers, with small changes in fluorescence spectra. Further, electron transport is blocked at the acceptor side of photosystem II. Disappearance or inactivation of photosystem-II reaction centers after a 50% loss of chlorophyll is accompanied by a sharp increase of the F0 yield, with small changes in the chlorophyll state. The slow-decay phase in fluorescence induction of these cells, enhanced by dithionite, is ascribed to a reversible photobleaching of chlorophyll during the measurement.Second: Oxadiazon and oxyfluorfen alter substantially the state of chlorophylls and cause strong bleaching, but reaction centers of photosystem II, although less than in control cells, are active even after an 80% disappearance of chlorophyll. The yields of F0 and (Fmax - F0) in treated cells are independent of the extent of chlorophyll bleaching. In contrast to norflurazon, the latter two herbicides do not inhibit carotenogenesis. Decrease of photosystem-II reaction centers may be due to non-specific pigment destruction (oxyfluorfen) or interference w'ith chlorophyll biosynthesis.

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.

Fluorometric Detection of Photosystem II Herbicide Penetration and Detoxification in Whole Leaves

Weed Science ◽  
1984 ◽  
Vol 32 (5) ◽  
pp. 675-680 ◽  
Author(s):  
Manfred Voss ◽  
Gernot Renger ◽  
Clemens Kötter ◽  
Peter Gräber
Keyword(s):  
Photosystem Ii ◽  
Foliar Application ◽  
Fluorescence Induction ◽  
Fluorometric Detection ◽  
Variable Fluorescence ◽  
Ps Ii ◽  
Fluorescence Measurements ◽  
Detoxification Mechanism ◽  
Herbicide Effects ◽  
Kinetics Of

The applicability of fluorescence measurements for the detection of herbicide effects in whole leaves was analyzed. Based on the results known for isolated chloroplasts, normalized variable fluorescence of the initial rise was shown to be an appropriate tool for monitoring effects of photosystem II (PS II) herbicides. Equipment is described for monitoring the degree of inhibition by fluorescence induction measurements and microcomputer data analysis. The method is used to study the effect of pyrazon [5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone], BAY DRW 1139 [4-amino-3-methyl-6-phenyl-1,2,4-triazin-5(4H)-one], and phenmedipham {3-[(methoxycarbonyl)amino] phenyl (3-methyl-phenyl)carbamate} after foliar application to different species. A rapid decrease of normalized variable fluorescence indicates penetration into leaf cells of all species tested. During a 5- to 7-day experiment, the apparent variable fluorescence decreased continuously in herbicide-susceptible plants, while it recovered in resistant plants due to an internal detoxification mechanism. The described method provides a rapid, simple, and nondestructive tool for analyzing the kinetics of penetration and detoxification of PS II herbicides in whole leaves.

scholarly journals OJIP chlorophyll fluorescence induction profiles and plastoquinone binding affinity of the Photosystem II assembly intermediate PSII-I from Thermosynechococcus elongatus

2021 ◽  
Author(s):  
Jure Zabret ◽  
Marc M Nowaczyk
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Binding Affinity ◽  
Conformational Changes ◽  
Charge Recombination ◽  
Fluorescence Induction ◽  
Chlorophyll Fluorescence Induction ◽  
Acceptor Side ◽  
Assembly Intermediate

Binding of Psb28 to the photosystem II assembly intermediate PSII-I induces conformational changes to the PSII acceptor side that impact charge recombination and reduce the in situ production of singlet oxygen (Zabret et al. 2021, Nat. Plants 7, 524-538). A detailed fluorometric analysis of the PSII-I assembly intermediate compared with OEC-disrupted and Mn-depleted PSII complexes showed differences between their variable (OJIP) chlorophyll fluorescence induction profiles. These revealed a distinct destabilisation of the QA- state in the PSII-I assembly intermediate and inactivated PSII samples related to an increased rate of direct and safe charge recombination. Furthermore, inactivation or removal of the OEC increases the binding affinity for plastoquinone analogues like DCBQ to the different PSII complexes. These results might indicate a mechanism that further contributes to the protection of PSII during biogenesis or repair.

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