Chlorophyll fluorescence images demonstrate variable pathways in the effects of plasma membrane excitation on electron flow in chloroplasts of Chara cells

Abscisic acid (ABA) is an important hormone in plants that participates in their acclimation to the action of stressors. Treatment by exogenous ABA and its synthetic analogs are a potential way of controlling the tolerance of agricultural plants; however, the mechanisms of influence of the ABA treatment on photosynthetic processes require further investigations. The aim of our work was to investigate the participation of inactivation of the plasma membrane H+-ATP-ase on the influence of ABA treatment on photosynthetic processes and their regulation by electrical signals in peas. The ABA treatment of seedlings was performed by spraying them with aqueous solutions (10−5 M). The combination of a Dual-PAM-100 PAM fluorometer and GFS-3000 infrared gas analyzer was used for photosynthetic measurements; the patch clamp system on the basis of a SliceScope Pro 2000 microscope was used for measurements of electrical activity. It was shown that the ABA treatment stimulated the cyclic electron flow around photosystem I and decreased the photosynthetic CO2 assimilation, the amplitude of burning-induced electrical signals (variation potentials), and the magnitude of photosynthetic responses relating to these signals; in contrast, treatment with exogenous ABA increased the heat tolerance of photosynthesis. An investigation of the influence of ABA treatment on the metabolic component of the resting potential showed that this treatment decreased the activity of the H+-ATP-ase in the plasma membrane. Inhibitor analysis using sodium orthovanadate demonstrated that this decrease may be a mechanism of the ABA treatment-induced changes in photosynthetic processes, their heat tolerance, and regulation by electrical signals.

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Effect of Plasma Membrane Ion Currents on Chlorophyll Fluorescence and Excitation Quenching in Chara Chloroplasts

Biochemistry (Moscow) Supplement Series A Membrane and Cell Biology ◽

10.1134/s1990747820040042 ◽

2020 ◽

Vol 14 (4) ◽

pp. 310-318

Author(s):

A. A. Bulychev ◽

N. A. Krupenina ◽

A. A. Cherkashin

Keyword(s):

Plasma Membrane ◽

Chlorophyll Fluorescence ◽

Ion Currents

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Analysis of the control of photosynthesis in C 4 plants by changes in light and carbon dioxide

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1989.0015 ◽

1989 ◽

Vol 323 (1216) ◽

pp. 339-355 ◽

Cited By ~ 6

Keyword(s):

Chlorophyll Fluorescence ◽

Fluorescence Quenching ◽

Electron Flow ◽

Calvin Cycle ◽

Carbon Assimilation ◽

Photon Flux ◽

Low Light ◽

Chlorophyll Fluorescence Quenching ◽

Photosynthetic Carbon ◽

Photosynthetic Carbon Assimilation

Parallel measurements of contents of photosynthetic intermediates, activities of enzymes of photosynthetic carbon assimilation, gas-exchange rates and components of chlorophyll-fluorescence quenching in leaves of C 4 plants are considered in relation to changes in photon flux density (PFD) and CO 2 . The influence of varying light and CO 2 concentration upon changes in the amounts of phosphoenolpyruvate (PEP) in leaves of C 4 plants during steady-state photosynthesis are interpreted in terms of the regulatory properties of PEP carboxylase and in terms of feedback interactions between the Calvin cycle and the C 4 cycle. Relations between electron transport and carbon assimilation are discussed in terms of the regulation of the supply of ATP and NADPH and the demands of carbon assimilation. In low light these relations differ in C 3 and C 4 plants. The lag in photosynthetic carbon assimilation in maize that follows a decrease in PFD has been analysed. The changes that occur in enzyme activities, metabolites and components of chlorophyll-fluorescence quenching following the transition from high to low light indicate that diminished production of ATP and NADPH is responsible for the lag in photosynthetic carbon assimilation and may reflect a stimulation of cyclic electron flow to make up a deficit in ATP.

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Interchloroplast communications in Chara are suppressed under the alkaline bands and are relieved after the plasma membrane excitation

Bioelectrochemistry ◽

10.1016/j.bioelechem.2019.05.006 ◽

2019 ◽

Vol 129 ◽

pp. 62-69 ◽

Cited By ~ 3

Author(s):

Alexander A. Bulychev ◽

Natalia A. Krupenina

Keyword(s):

Plasma Membrane ◽

Membrane Excitation

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The Inhibition of Photosynthetic Light Reactions by Halogenated Naphthoquinones

Zeitschrift für Naturforschung C ◽

10.1515/znc-1981-7-824 ◽

1981 ◽

Vol 36 (7-8) ◽

pp. 645-655 ◽

Cited By ~ 23

Author(s):

Klaus Pfister ◽

Hartmut K. Lichtenthaler ◽

Günther Burger ◽

Hans Musso ◽

Manuel Zahn

Keyword(s):

Chlorophyll Fluorescence ◽

Electron Transport ◽

Binding Site ◽

Chlorophyll A ◽

Electron Flow ◽

Photosynthetic Electron Transport ◽

Ps Ii ◽

Photosynthetic Electron Flow ◽

A Site ◽

Fluorescence Transients

Abstract Halogenated naphthoquinones act as inhibitors of photosynthetic electron flow. I50 concentra tion for inhibition of methylviologen reduction were found to range between 2 × 10-5 m to 2 × 10-6 M. Comparing their effects on several partial reactions of electron flow, the inhibition site of the naphthoquinones was found to be at the reducing site of PS II. Studies of fluorescence transients in presence of halogenated naphthoquinones give further evidence for a site action similar to that of diuron and different to that of DBMIB. All naphthoquinones act as quenchers of chlorophyll fluorescence with pure chlorophyll a, and with much higher efficiency in green algae and chloroplasts. It is concluded, that the halogenated naphthoquinones act similar to PS II-inhibitors like diuron, but do not share a common binding site at the PS II-complex. Implications of a possible involvement of phylloquinone K 1 in photosynthetic electron transport are discussed. The synthesis of 2-chloro-as well as 2-bromo-3-isopropyl-1,4-naphthoquinone is described.

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Adaptation of a Chlamydomonas mutant with reduced rate of photorespiration to different concentrations of CO2

Canadian Journal of Botany ◽

10.1139/b05-068 ◽

2005 ◽

Vol 83 (7) ◽

pp. 834-841 ◽

Cited By ~ 1

Author(s):

Kensaku Suzuki ◽

Hidenori Onodera

Keyword(s):

Chlorophyll Fluorescence ◽

Chlamydomonas Reinhardtii ◽

Inorganic Carbon ◽

Electron Flow ◽

Effective Quantum Yield ◽

Wild Type ◽

Chlorophyll Fluorescence Parameters ◽

Phosphoglycolate Phosphatase ◽

Concentrating Mechanism ◽

Type Strains

It has been widely accepted that Chlamydomonas reinhardtii cells utilize inorganic carbon very efficiently for photosynthesis by operating a CO2-concentrating mechanism (CCM) under conditions of limited CO2. To help define the mechanism, 7FR2N, one of the suppressor double mutants of phosphoglycolate phosphatase-deficient (pgp1) mutants that have a reduced photorespiration rate (RPR) was crossed with wild-type strains to generate the strain N21 as a single RPR mutant. The comparison of photosynthetic characteristics with wild-type strains after the cells adapted to different concentrations of CO2 revealed that photosynthetic affinity for inorganic carbon was higher than that in wild-type strains after adaptation to concentrations between 50 µL·L1 CO2 and 5% CO2. Chlorophyll fluorescence parameters were also compared, and the biggest difference between N21 and the wild-type strains was observed in the photochemical quenching and effective quantum yield of photosystem II (ΔF/Fm′) at the CO2 compensation point. These values in N21 increased in a similar manner to the photosynthetic affinity for CO2, and increased significantly when the cells adapted to low-CO2 levels, whereas the values in the wild-type strains were apparently lower without any significant changes, regardless of the CO2 concentrations to which they were adapted. Although it was not clear if a nonphotochemical quenching parameter (NPQ) in N21 was higher than that in wild-type strains, NPQ increased coincidentally with the increase in photosynthetic affinity for inorganic carbon when the CO2 concentrations to which the strains were adapted decreased, in both the mutant and wild-type strain, suggesting that this form of NPQ reflects the operation of CCM in certain conditions. Possible candidates for the RPR mutation and the relationship between CCM and photosynthetic electron flow are discussed.Key words: Chlamydomonas reinhardtii, chlorophyll fluorescence, CO2-concentrating mechanism, low-CO2 responsive gene, phosphoglycolate phosphatase, photorespiration.

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