scholarly journals Change in H+ Transport across Thylakoid Membrane as Potential Mechanism of 14.3 Hz Magnetic Field Impact on Photosynthetic Light Reactions in Seedlings of Wheat (Triticum aestivum L.)

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2207
Author(s):  
Ekaterina Sukhova ◽  
Ekaterina Gromova ◽  
Lyubov Yudina ◽  
Anastasiia Kior ◽  
Yana Vetrova ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Photosystem Ii ◽  
Thylakoid Membrane ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Terrestrial Plants ◽  
Short Term ◽  
Low Frequencies ◽  
Resonance Frequencies ◽  
Non Photochemical Quenching

Natural and artificial extremely low-frequency magnetic fields (ELFMFs) are important factors influencing physiological processes in living organisms including terrestrial plants. Earlier, it was experimentally shown that short-term and long-term treatments by ELFMFs with Schumann resonance frequencies (7.8, 14.3, and 20.8 Hz) influenced parameters of photosynthetic light reactions in wheat leaves. The current work is devoted to an analysis of potential ways of this ELFMF influence on the light reactions. Only a short-term wheat treatment by 14.3 Hz ELFMF was used in the analysis. First, it was experimentally shown that ELFMF-induced changes (an increase in the effective quantum yield of photosystem II, a decrease in the non-photochemical quenching of chlorophyll fluorescence, a decrease in time of changes in these parameters, etc.) were observed under the action of ELFMF with widely ranging magnitudes (from 3 to 180 µT). In contrast, the potential quantum yield of photosystem II and time of relaxation of the energy-dependent component of the non-photochemical quenching were not significantly influenced by ELFMF. Second, it was shown that the ELFMF treatment decreased the proton gradient across the thylakoid membrane. In contrast, the H+ conductivity increased under this treatment. Third, an analysis of the simplest mathematical model of an H+ transport across the thylakoid membrane, which was developed in this work, showed that changes in H+ fluxes related to activities of the photosynthetic electron transport chain and the H+-ATP synthase were not likely a mechanism of the ELFMF influence. In contrast, changes induced by an increase in an additional H+ flux (probably, through the proton leakage and/or through the H+/Ca2+ antiporter activity in the thylakoid membrane) were in good accordance with experimental results. Thus, we hypothesized that this increase is the mechanism of the 14.3 Hz ELFMF influence (and, maybe, influences of other low frequencies) on photosynthetic light reactions in wheat.

scholarly journals Influence of Magnetic Field with Schumann Resonance Frequencies on Photosynthetic Light Reactions in Wheat and Pea

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 149
Author(s):  
Vladimir Sukhov ◽  
Ekaterina Sukhova ◽  
Yulia Sinitsyna ◽  
Ekaterina Gromova ◽  
Natalia Mshenskaya ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Chronic Treatment ◽  
Quantum Yields ◽  
Photochemical Quenching ◽  
Schumann Resonance ◽  
Short Term ◽  
Resonance Frequencies ◽  
Non Photochemical Quenching

Photosynthesis is an important target of action of numerous environmental factors; in particular, stressors can strongly affect photosynthetic light reactions. Considering relations of photosynthetic light reactions to electron and proton transport, it can be supposed that extremely low frequency magnetic field (ELFMF) may influence these reactions; however, this problem has been weakly investigated. In this paper, we experimentally tested a hypothesis about the potential influence of ELFMF of 18 µT intensity with Schumann resonance frequencies (7.8, 14.3, and 20.8 Hz) on photosynthetic light reactions in wheat and pea seedlings. It was shown that ELFMF decreased non-photochemical quenching in wheat and weakly influenced quantum yield of photosystem II at short-term treatment; in contrast, the changes in potential and effective quantum yields of photosystem II were observed mainly under chronic action of ELFMF. It is interesting that both short-term and chronic treatment decreased the time periods for 50% activation of quantum yield and non-photochemical quenching under illumination. Influence of ELFMF on pea was not observed at both short-term and chronic treatment. Thus, we showed that ELFMF with Schumann resonance frequencies could influence photosynthetic light processes; however, this effect depends on plant species (wheat or pea) and type of treatment (short-term or chronic).

scholarly journals Physiological characterization of grapevine rootstocks grown in soil with increasing zinc doses

2015 ◽  
Vol 19 (10) ◽  
pp. 973-980 ◽  
Author(s):  
Jovani Zalamena ◽  
George W. Melo ◽  
Henrique P. Santos ◽  
Leandro S. da Silva ◽  
Flavio B. Fialho ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Photosystem Ii ◽  
Fluorescence Analysis ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Physiological Characterization ◽  
Physiological Variables ◽  
Negative Effect ◽  
Soil Zn ◽  
Non Photochemical Quenching

ABSTRACTThis study aimed to evaluate the performance of grapevine rootstocks under increasing levels of Zn in the soil and to identify physiological variables that can be used as indicators of excess of Zn in the soil. The rootstocks SO4, Paulsen1103, IAC572, IAC313 and 420A were grown in pots containing soil, which received Zn doses of 0, 20, 40, 80 or 160 mg kg-1 of soil. Dry matter (DM), Zn content in shoots and roots, chlorophyll index, initial fluorescence (Fo), maximum fluorescence (Fm), maximum quantum yield of photosystem II (Fv/Fm), effective quantum yield of photosystem II (Y-II) and non-photochemical quenching (NPQ) were evaluated. The increase of Zn levels in the soil decreased DM in all rootstocks, and IAC572 was superior to the others. The variation in the indices of chlorophyll a and b had little expression in relation the soil Zn levels, but allowed identifying that the rootstocks Paulsen 1103, 420A and SO4 are sensitive to Zn toxicity and that IAC572 and IAC313 were not sensitive to the tested levels. Fluorescence analysis showed a negative effect of Zn contents on the variables Fo, Fm, Y-II and NPQ in all rootstocks, which proved to be good indicators of Zn phytotoxicity.

scholarly journals Changes in Photo-Protective Energy Dissipation of Photosystem II in Response to Beneficial Bacteria Consortium in Durum Wheat under Drought and Salinity Stresses

2020 ◽  
Vol 10 (15) ◽  
pp. 5031 ◽  
Author(s):  
Mohammad Yaghoubi Khanghahi ◽  
Sabrina Strafella ◽  
Carmine Crecchio
Keyword(s):  
Chlorophyll Fluorescence ◽  
Energy Dissipation ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Excitation Energy ◽  
Durum Wheat ◽  
Photochemical Quenching ◽  
Plant Growth Promoting Bacteria ◽  
Psii Photochemistry ◽  
Non Photochemical Quenching

The present research aimed at evaluating the harmless dissipation of excess excitation energy by durum wheat (Triticum durum Desf.) leaves in response to the application of a bacterial consortium consisting of four plant growth-promoting bacteria (PGPB). Three pot experiments were carried out under non-stress, drought (at 40% field capacity), and salinity (150 mM NaCl) conditions. The results showed that drought and salinity affected photo-protective energy dissipation of photosystem II (PSII) increasing the rate of non-photochemical chlorophyll fluorescence quenching (NPQ (non-photochemical quenching) and qCN (complete non-photochemical quenching)), as well as decreasing the total quenching of chlorophyll fluorescence (qTQ), total quenching of variable chlorophyll fluorescence (qTV) and the ratio of the quantum yield of actual PSII photochemistry, in light-adapted state to the quantum yield of the constitutive non-regulatory NPQ (PQ rate). Our results also indicated that the PGPB inoculants can mitigate the adverse impacts of stresses on leaves, especially the saline one, in comparison with the non-fertilized (control) treatment, by increasing the fraction of light absorbed by the PSII antenna, PQ ratio, qTQ, and qTV. In the light of findings, our beneficial bacterial strains showed the potential in reducing reliance on traditional chemical fertilizers, in particular in saline soil, by improving the grain yield and regulating the amount of excitation energy.

scholarly journals Acclimatization of photosynthetic apparatus and antioxidant metabolism to excess soil cadmium in Buddleja spp.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Weichang Gong ◽  
Bruce L. Dunn ◽  
Yaqing Chen ◽  
Yunmei Shen
Keyword(s):  
Quantum Yield ◽  
Photosynthetic Apparatus ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Antioxidant Metabolism ◽  
Cellular Reactive Oxygen Species ◽  
Soil Cadmium ◽  
Non Photochemical Quenching ◽  
Cd Translocation ◽  
Physiological And Biochemical

AbstractHeavy metal (HM) pollutants can cause serious phytotoxicity or oxidative stress in plants. Buddleja L., commonly known as “butterfly bushes”, are frequently found growing on HM-contaminated land. However, to date, few studies have focused on the physiological and biochemical responses of Buddleja species to HM stress. In this study, potted seedlings of B. asiatica Lour. and B. macrostachya Wall. ex Benth. were subjected to various cadmium (Cd) concentrations (0, 25, 50, 100, and 200 mg kg−1) for 90 days. Both studied Buddleja species showed restricted Cd translocation capacity. Exposure to Cd, non-significant differences (p > 0.05) were observed, including quantum yield of photosystem II (PSII), effective quantum yield of PSII, photochemical quenching and non-photochemical quenching in both species between all studied Cd concentrations. Moreover, levels of cellular reactive oxygen species (ROS) significantly declined (p < 0.05) with low malondialdehyde concentrations. In B. asiatica, high superoxide dismutase and significantly enhanced (p < 0.05) peroxidase (POD) activity contributed greatly to the detoxification of excess ROS, while markedly enhanced POD activity was observed in B. macrostachya. Additionally, B. macrostachya showed higher membership function values than did B. asiatica. These results suggested that both Buddleja species exhibited high Cd resistance and acclimatization.

scholarly journals Fibrillin 2 interacts with other proteins to protect photosystem II against abiotic stress in Arabidopsis thaliana

2020 ◽  
Author(s):  
Diego Torres-Romero ◽  
Ángeles Gómez-Zambrano ◽  
Antonio Jesús Serrato ◽  
Mariam Sahrawy ◽  
Ángel Mérida
Keyword(s):  
Abiotic Stress ◽  
Photosystem Ii ◽  
Higher Plants ◽  
Photochemical Quenching ◽  
Allene Oxide ◽  
Effective Quantum Yield ◽  
Metabolic Processes ◽  
Lower Maximum ◽  
Non Photochemical Quenching ◽  
Oxide Synthase

ABSTRACTFibrillins (FBNs) are plastidial proteins found in photosynthetic organisms, from cyanobacteria to higher plants. The function of most FBNs is largely unknown. We focused on the subgroup formed by FBN1a, −1b, and −;2, which has been proposed to be involved in the photoprotection of photosystem II (PSII), though their mechanism of action has not yet been characterized. We show that FBN2 interacts with FBN1a and with other FBN2 polypeptides, potentially forming a network around the plastoglobule surface. Both FBN2 and FBN1 interact with the allene oxide synthase, and the elimination of any of these FBNs results in a delay in jasmonate-mediated anthocyanin accumulation in response to a combination of moderate-high light and low temperature. FBN2 also interacts with other proteins involved in different metabolic processes. Mutants lacking FBN2 demonstrate less photoprotection of PSII, alterations that are not found in fbn1a-fbn1b mutants. We also show that FBN2 interacts with Acclimation of Photosynthesis to Environment 1 (APE1), and gene co-expression analysis suggests that both proteins are involved in the same metabolic process. The elimination of APE1 leads to lesions in PSII under abiotic stress similar to observations in fbn2 mutants, with lower maximum and effective quantum yield. However, a reduction in non-photochemical quenching is observed exclusively in fbn2 mutants, suggesting that other FBN2-interacting proteins are responsible for this alteration. We propose that FBN2 facilitates accurate positioning of different proteins involved in distinct metabolic processes, and its elimination leads to dysfunction in those proteins.One sentence summaryFibrillin 2 protects photosynthesis against abiotic stresses by facilitating the accurate positioning of different proteins involved in distinct processes, and its elimination leads to dysfunction in those proteins

scholarly journals Temperature-dependent chlorophyll accumulation and photosystem II assembly during etioplast to chloroplast transition in sunflower cotyledons

2017 ◽  
Vol 76 (1) ◽  
pp. 107-110
Author(s):  
Hrvoje Lepeduš ◽  
Mario Jakopec ◽  
Jasenka Antunović Dunić ◽  
Goran Krizmanić ◽  
Sanida Osmanović ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Photosystem Ii ◽  
Heat Dissipation ◽  
Higher Plants ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Chlorophyll Accumulation ◽  
Different Temperatures ◽  
The Impact ◽  
Quantum Yield Of Psii

Abstract Despite numerous data dealing with the biogenesis of photosynthetic membranes connected with specific functional alterations in higher plants this is still an insufficiently understood topic and is one of the most promising areas of research in plant biochemistry. The main goal of our study was to detect the impact of different temperatures on chlorophyll biosynthesis and the maximum quantum yield of PSII (Fv/Fm). Therefore, we investigated the greening processes in etiolated sunflower cotyledons (Helianthus annuus L.) grown at different temperatures (10, 20 and 30 °C) during 24 h. The dynamics of chlorophyll a and b (Chl a and Chl b) accumulation as well as photosystem II (PSII) effi ciency were observed. We also evaluated combined effects of different temperatures (20 and 30 °C) and short-term application of increased irradiation (800 μmol m-2 s-1) on effective quantum yield of PSII (ΔF/F’m) and non photochemical quenching (NPQ) in cotyledons with fully developed PSII. Our results showed reduced chlorophyll accumulation and the arrest of PSII assembly at 10 °C in comparison with 20 and 30 °C. Further, the increased irradiance induced equal down regulation of effective quantum yield of PSII at 20 and 30 °C, with significantly higher capability of heat dissipation at 30 °C.

scholarly journals Photoacclimation in three species of freshwater red algae

2007 ◽  
Vol 19 (1) ◽  
pp. 23-34 ◽  
Author(s):  
Anna I.N. Bautista ◽  
Orlando Necchi Jr.
Keyword(s):  
Quantum Yield ◽  
High Irradiance ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Low Light ◽  
Recovery Capacity ◽  
Long Time ◽  
Freshwater Red Algae ◽  
Non Photochemical Quenching ◽  
Short Time

Three freshwater Rhodophyta species (Audouinella eugenea, A. hermannii and Compsopogon coeruleus) were tested as to their responses (photosynthesis, growth and pigment concentration) to two irradiances (low light, LL, 65 µmol m-2 s-1 and high light, HL, 300 µmol m-2 s-1) and two periods (short time, ST, 4 d, and long time, LT, 28 d). Higher growth rates were consistently observed at LL but significant differences were observed only for A. hermannii. Higher values of photoinhibition at LL were found for the three species, which is consistent with the dynamic photoinhibition as a reversible photoprotective mechanism against high irradiance. Light-induced decreases of effective quantum yield (EQY) were observed in the three species consisting of pronounced decreases from LL to HL. Rapid increases of non-photochemical quenching (NPQ) were observed mainly at LL, indicating energy dissipation by reaction centers. Results revealed distinct photoacclimation strategies to deal with high irradiances: the two Audouinella species had only characteristics of shade-adapted algae: acclimation by changes of size of photosystem units (PSU) under LT and by PSU number under ST; higher values of the photoinhibition parameter (beta) and NPQ, and lower values of EQY at LL; higher recovery capacity of potential quantum yield (PQY) at LL and under ST; highly significant positive correlation of electron transport rate (ETR) with NPQ. In addition, C. coeruleus mixed some characteristics of sun-adapted algae: acclimation by changes of PSU number under LT and by PSU size under ST; higher recovery capacity of EQY than the other two species; weak or no correlation of ETR with NPQ. Thus, these characteristics indicate that C. coeruleus cope with high irradiances more efficiently than the Audouinella species.

scholarly journals Photosynthetic Potential and Productivity of Common Beans under Herbicide Effect

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
G.R. LIMA ◽  
D.C. MACEDO ◽  
R.L.N. BARROS ◽  
A.F.L. MACHADO ◽  
C. PIMENTEL
Keyword(s):  
Quantum Yield ◽  
Photosystem Ii ◽  
Common Bean ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Environmental Influence ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Herbicide Application ◽  
Fluorescence Parameters

ABSTRACT: The objective of this study was to evaluate the effects of the application of contact herbicides recommended for common bean crops, as for chlorophyll a fluorescence parameters, leaf soluble proteins content (LSPC) and productivity. The experiment was conducted on the field with five treatments, which were the application of the following herbicides: bentazon (720 g ha-1), fluazifop-p-butil (187.5 g ha-1), fomesafen (250 g ha-1) fluazifop-p-butil + fomesafen (187.5 + 250 g ha-1), and a manually weeded control treatment without herbicide application, in a randomized block design with four replications. Bentazon was the only herbicide causing significant reductions, but only until the first day after herbicide application (DAA), on the following chlorophyll a fluorescence parameters: maximum quantum yield of photosystem II (Fv/Fm), effective quantum yield of photosystem II (ϕPSII), photochemical quenching (qP); it also induced an increase in non-photochemical quenching (NPQ). Fv/Fm was the best parameter to indicate herbicide effect on the photosynthetic apparatus of plants in the field. Chlorophyll a fluorescence parameters obtained in light-adapted leaves underwent a high environmental influence, especially deriving from the variation in the photosynthetic photon flow density (PPFD) during measurements; they are not recommended to evaluate the effects of herbicides on the field. None of the applied herbicides evaluated caused reductions in grain yield; therefore, they are recommended for common bean crops.

Photosynthetic and antioxidant responses of the tropical intertidal seagrasses Halophila ovalis and Thalassia hemprichii to moderate and high irradiances

2018 ◽  
Vol 61 (3) ◽  
pp. 247-256 ◽  
Author(s):  
Surangkana Phandee ◽  
Pimchanok Buapet
Keyword(s):  
Oxidative Stress ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
High Irradiance ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Thalassia Hemprichii ◽  
Sod Activity ◽  
Halophila Ovalis ◽  
And Oxidative Stress

Abstract This study investigated photosynthetic and oxidative stress-related responses to moderate (500 μmol photons m−2 s−1) and high irradiances (1500 μmol photons m−2 s−1) in two tropical intertidal seagrasses, Halophila ovalis and Thalassia hemprichii. Exposure to high irradiance for 3 h resulted in a large decline in the maximum quantum yield of photosystem II (Fv/Fm) and in the effective quantum yield of photosystem II (ΦPSII) but induced non-photochemical quenching (NPQ) and chloroplast clumping in H. ovalis. Thalassia hemprichii, however, showed only a minor decrease in Fv/Fm and ΦPSII, and no change in either NPQ or the intracellular arrangement of chloroplasts. The irradiance did not affect reactive oxygen species (ROS) or superoxide dismutase (SOD) activity in either seagrass, whereas high irradiance enhanced ascorbate peroxidase (APX) activity in H. ovalis. The results from a subsequent experiment using an oxidative stress inducer, methyl viologen (MV), also showed a higher degree of Fv/Fm inhibition in H. ovalis. These results show that H. ovalis is much more physiologically responsive to high irradiances and oxidative stress than T. hemprichii and that its photoprotective mechanisms involve NPQ, APX and reduction of the amount of light absorbed through the clumping of its chloroplasts.

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