Changes in P-700 Oxidation during the Early Stages of the Induction of Photosynthesis

Harbinson, Jeremy; Hedley, C. L.

doi:10.1104/pp.103.2.649

Cited by 85 publications

(71 citation statements)

References 40 publications

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“…4) suggesting only a small down-regulation of electron transport in response to the inhibition of photorespiration. Measurements of F PSI provide similar information to F PSII, but with additional information about the redox state of the PSI acceptor pool and the kinetics of the electron transfer between the photosystems (Harbinson and Hedley 1993). Similar to what was observed for F PSII660nm , F PSI decreased with increasing irradiance (Fig.…”

Section: Plant Growthsupporting

confidence: 72%

Influence of the acetolactate synthase inhibitor metsulfuron-methyl on the operation, regulation and organisation of photosynthesis in Solanum nigrum

et al. 2006

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The influence of the acetolactate synthase inhibitor metsulfuron-methyl on the operation of the photosynthetic apparatus was examined on 4-weeksold climate chamber-grown Solanum nigrum plant. To have an indication on the relative performance of the photosynthetic apparatus of ALS-treated plants, the level of carbon dioxide (CO 2 ) fixation, the relative quantum efficiency of photosystem I (F PSI ) or photosystem II (F PSII ) electron transport and leaf chlorophyll content were assessed for both control and treated plants at 2, 4 and 7 days after application of the herbicide. Results indicated a progressive inhibition of the level of CO 2 fixation, the relative quantum efficiency of photosystem I (F PSI ) and II (F PSII ) electron transport and the leaf chlorophyll content already 2 days after application of the herbicide. The linear relationship between the photosystem I and II was unaltered by herbicidal treatment and was sustained under conditions where large changes in pigment composition of the leaves occurred. It appears that the stressinduced loss of leaf chlorophyll is not a catastrophic process but rather is the consequence of a well-organised breakdown of components. Under photorespiratory and non-photorespiratory conditions, the relationship between the index of electron transport flow through photosystem I and II and the rate of CO 2 fixation is altered so that electron transport becomes less efficient at driving CO 2 fixation.Keywords Herbicide AE Photosystem I AE Photosystem II AE Quantum efficiency AE Sulfonylurea AE CO 2 fixation AE Chlorophyll AE Chlorophyll fluorescence Abbreviations ALS acetolactate synthase DAT days after treatment HRAC herbicide resistance action committee F PSI relative quantum efficiency of photosystem I F PSII relative quantum efficiency of photosystem II

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Section: Plant Growthsupporting

confidence: 72%

Influence of the acetolactate synthase inhibitor metsulfuron-methyl on the operation, regulation and organisation of photosynthesis in Solanum nigrum

et al. 2006

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“…In the absence of the protonophore, ΔA 810 signal com prised two waves of P700 oxidation. It has been pro posed that the second wave of P700 photooxidation in leaves irradiated with WL after WL preillumination is associated with FNR activation [10,20,21]. The pro tonophore FCCP was found to eliminate the second wave of P700 photooxidation.…”

Section: Formal Description Of the P700 Oxidation Kinetics In Frmentioning

confidence: 97%

“…One approach to study CET in plant leaves consists in analysis of absorbance changes attributed to redox state of the reaction center chlorophyll of PSI, P700 [3,10,11]. The P700 redox state can be monitored from differential absorbance changes at 810 nm with respect to 870 nm (ΔA 810 ) [11].…”

Section: Introductionmentioning

confidence: 99%

Induction kinetics of photosystem I-activated P700 oxidation in plant leaves and their dependence on pre-energization

Булычев

Vredenberg

2010

Russ J Plant Physiol

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Abstract-Absorbance changes ΔA 810 were measured in pea (Pisum sativum L., cv. Premium) leaves to track redox transients of chlorophyll P700 during and after irradiation with far red (FR) light under various preil lumination conditions in the absence and presence of inhibitors and protonophorous uncoupler of photosyn thetic electron transport. It was shown that cyclic electron transport (CET) in chloroplasts of pea leaves oper ates at its highest rate after preillumination of leaves with white light and is strongly suppressed after preillu mination with FR light. The FR light induced suppression was partly released during prolonged dark adaptation. Upon FR illumination of dark adapted leaves, the induction of CET was observed, during which CET activity increased to the peak from the low level and then decreased gradually. The kinetics of P700 oxi dation induced by FR light of various intensities in leaves preilluminated with white light were fit to empirical sigmoid curves containing two variables. In leaves treated with a protonophore FCCP, the amplitude of FR light induced changes ΔA 810 was strongly suppressed, indicating that the rate of CET is controlled by the pH gradient across the thylakoid membrane.

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“…For complete reduction of Q A , leaves were exposed to pulses of saturating light (1 s; flux density 6000 mol quanta m Ϫ2 s Ϫ1 ). The redox state of the PSI reaction center chlorophyll P700 was monitored by following the changes in absorbance of dark-adapted leaves from wild-type and mutant plants at a 830-nm wavelength (19,20). Absorbance measurements were performed using the pulsed amplitude modulation fluorimeter with a modified emitter/ detector unit.…”

Section: Plant Materials and Growth Conditions-sterile Tobacco Plants mentioning

confidence: 99%

“…Absorption changes at 830 nm correlate with the redox state of the PSI reaction center chlorophyll, P700. In the dark, P700 is present in its reduced form (19). Illumination of dark-adapted leaves with far red light selectively excites PSI, thereby converting P700 in its oxidized form (Fig.…”

Section: Figmentioning

confidence: 99%

Lack of the Small Plastid-encoded PsbJ Polypeptide Results in a Defective Water-splitting Apparatus of Photosystem II, Reduced Photosystem I Levels, and Hypersensitivity to Light

Hager

Hermann

Biehler

et al. 2002

Journal of Biological Chemistry

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Photosystem II is a large pigment-protein complex catalyzing water oxidation and initiating electron transfer processes across the thylakoid membrane. In addition to large protein subunits, many of which bind redox cofactors, photosystem II particles contain a number of low molecular weight polypeptides whose function is only poorly defined. Here we have investigated the function of one of the smallest polypeptides in photosystem II, PsbJ. Using a reverse genetics approach, we have inactivated the psbJ gene in the tobacco chloroplast genome. We show that, although the PsbJ polypeptide is not principally required for functional photosynthetic electron transport, plants lacking PsbJ are unable to grow photoautotrophically. We provide evidence that this is due to the accumulation of incompletely assembled water-splitting complexes, which in turn causes drastically reduced photosynthetic performance and extreme hypersensitivity to light. Our results suggest a role of PsbJ for the stable assembly of the water-splitting complex of photosystem II and, in addition, support a control of photosystem I accumulation through photosystem II activity. Photosystem II (PSII)1 is a large cofactor-protein complex consisting of at least 17 protein subunits (Ref. 1; for review, see e.g. Ref. 2). The PSII reaction center is formed by a heterodimer of two pigment-binding proteins, D1 and D2, which, in photosynthetic eukaryotes, are encoded by the chloroplast psbA and psbD genes, respectively. The photochemical reaction carried out by the reaction center converts the energy of a photon into a separation of charge and, in this way, initiates electron flow. Around the reaction center, the outer parts of PSII are assembled, the inner and outer antennae funneling absorbed light energy to the catalytic core and the oxygen-evolving complex splitting water into protons, electrons, and dioxygen (reviewed in Refs. 3 and 4).In addition to the well-studied large protein subunits, purified PSII particles contain a number of low molecular weight polypeptides, many of which are encoded by the plastid genome of photosynthetically active eukaryotes (5). Most of these small subunits do not bind redox cofactors and, hence, are unlikely to participate directly in electron transfer reactions. It is generally assumed that they rather function as photosystem-assembling or stabilizing factors. However, in many cases, molecular evidence supporting such a structural role is largely lacking. The successful development of transformation technologies for Chlamydomonas (6) and tobacco chloroplasts (7) has paved the way to functional characterizations of plastid genome-encoded genes by reverse genetics. Linked to a selectable marker gene, mutant alleles can be introduced into plastids by chloroplast transformation, where they replace the endogenous wildtype allele by homologous recombination. During the past decade, reverse genetics has become a powerful tool in plastid functional genomics (reviewed in Ref. 8).Here, we have taken a reverse genetics approach to def...

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Changes in P-700 Oxidation during the Early Stages of the Induction of Photosynthesis

Cited by 85 publications

References 40 publications

Influence of the acetolactate synthase inhibitor metsulfuron-methyl on the operation, regulation and organisation of photosynthesis in Solanum nigrum

Influence of the acetolactate synthase inhibitor metsulfuron-methyl on the operation, regulation and organisation of photosynthesis in Solanum nigrum

Induction kinetics of photosystem I-activated P700 oxidation in plant leaves and their dependence on pre-energization

Lack of the Small Plastid-encoded PsbJ Polypeptide Results in a Defective Water-splitting Apparatus of Photosystem II, Reduced Photosystem I Levels, and Hypersensitivity to Light

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