Heavy Metals and Photosynthesis: Recent Developments

Souri, Zahra; Cardoso, A. A.; da-Silva, Cristiane Jovelina; Oliveira, Luciana Magda de; Dari, Biswanath; Sihi, Debjani; Karimi, Naser

doi:10.1002/9781119501800.ch7

Cited by 47 publications

(27 citation statements)

References 156 publications

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“…It is quite evident that inhibition of light reactions during HM toxicity is because of the decreased efficiencies of PS I and PSII, which is a combined effect of reduced chlorophyll concentration and destabilized chloroplast and thylakoid membranes. On the other hand, inhibition of dark reactions is majorly because of the decreased activities of enzyme associated with the Calvin cycle [ 72 , 100 , 101 ].…”

Section: Hm Toxicity Negatively Influence the Photosynthesismentioning

confidence: 99%

A Comprehensive Review on the Heavy Metal Toxicity and Sequestration in Plants

et al. 2021

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Heavy metal (HM) toxicity has become a global concern in recent years and is imposing a severe threat to the environment and human health. In the case of plants, a higher concentration of HMs, above a threshold, adversely affects cellular metabolism because of the generation of reactive oxygen species (ROS) which target the key biological molecules. Moreover, some of the HMs such as mercury and arsenic, among others, can directly alter the protein/enzyme activities by targeting their –SH group to further impede the cellular metabolism. Particularly, inhibition of photosynthesis has been reported under HM toxicity because HMs trigger the degradation of chlorophyll molecules by enhancing the chlorophyllase activity and by replacing the central Mg ion in the porphyrin ring which affects overall plant growth and yield. Consequently, plants utilize various strategies to mitigate the negative impact of HM toxicity by limiting the uptake of these HMs and their sequestration into the vacuoles with the help of various molecules including proteins such as phytochelatins, metallothionein, compatible solutes, and secondary metabolites. In this comprehensive review, we provided insights towards a wider aspect of HM toxicity, ranging from their negative impact on plant growth to the mechanisms employed by the plants to alleviate the HM toxicity and presented the molecular mechanism of HMs toxicity and sequestration in plants.

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Section: Hm Toxicity Negatively Influence the Photosynthesismentioning

confidence: 99%

A Comprehensive Review on the Heavy Metal Toxicity and Sequestration in Plants

et al. 2021

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“…Plants facing environmental abiotic stress conditions stimulates the formation of reactive oxygen species (ROS) in chloroplast such as photorespiration, cyclic electron flows through either PSI or PSII consequences down-regulation of PSII quantum yield regulated by xanthophyll cycle and proton gradient across thylakoid membrane ( Gill et al., 2016 ). Photosystem II (PSII) is considered to be very sensitive and has great inhibitory effect under stress conditions ( Souri et al., 2019 ), by inhibiting the interaction between electron donor and acceptor end photosystem II (PSII) and induces some changes in I–P normalized bands which are linked with electric trans-thylakoids potential produced by protons pump regulated by cyclic electron transport in PSI during electron transfer from PQ or PQH 2 to PSI electron acceptor end i.e Fd and NADP.…”

Section: Introductionmentioning

confidence: 99%

Melatonin induced changes in photosynthetic efficiency as probed by OJIP associated with improved chromium stress tolerance in canola (Brassica napus L.)

Ayyaz

Amir

Umer

et al. 2020

Heliyon

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Chromium toxicity is considered as a major problem for agricultural soil that reduced crop productivity by affecting photosynthetic tissues. Exogenous application of melatonin can alleviate the adverse effects of chromium toxicity on plant growth. However, little is known about its effect on thylakoidal protein complexes responsible for conversion of solar energy to biochemical energy. Chlorophyll fluorescence a transients considered one of the best non-invasive and rapid method for the evaluation of photosynthetic (Photosystem II) efficiency of plants and plant health under environmental stress conditions. In the present study, three-week old plants of two canola cultivars AC-Excel and DGL were applied to melatonin (0, 1, 5, 10 μM) when grown under chromium stress (0, 50 and 100 μM) for further two weeks. Chromium stress reduced the growth (fresh and dry weights of shoots and roots) of both canola cultivars and exogenous application of 5 and 10 μM melatonin improved the growth of canola at 50 or 100 μM chromium stress. This improvement was greater in cv DGL than in AC-Excel. Increasing chromium decreased the photosynthetic pigments (chlorophyll a and chlorophyll b ). However, 5 and 10 μM melatonin application improved chlorophyll a at 50 μM chromium stress. Structural stability and efficiency of photosystem II (PSII) measured as performance index (PI ABS ) and ratios of fluorescence (Fv/Fm, Fv/Fo) Fv decreased due to chromium stress. JIP-test parameters showed that chromium stress increased the absorption and trapping fluxes with decrease in electron transport fluxes which caused the damage to reaction centers (RC), detachment of oxygen evolving complex (OEC) from RC or inefficiency of electron transfer from OEC to RC. Such adverse effects were greater in cv AC-Excel. However exogenous application of melatonin improved PI ABS , electron transport per reaction center (ET/RC), reduced variable fluorescence at J step (V J ) reflecting melatonin protected PSII from chromium stress induced damage by protecting OEC. Thus, OJIP fluorescence transients are quite helpful for understanding the intersystem electron transport beyond photosystem II in canola cultivars due to melatonin application under chromium stress. Findings Exogenous application of melatonin alleviated toxic effects of chromium on plant growth of canola by modulating photosynthesis, enhanced photosystem II efficiency and regulation of electron transport flux to protect photo-inhibition of PSII from oxidative damage.

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“…A similar accumulation in H 2 O 2 and MDA was reported in C3 (hordeum and wheat) and C4 (maize) plant species treated with different metal oxide NPs [ 17 , 44 , 48 ]. It is worth mentioned that heavy metals retard photosynthetic efficiency by diminishing NADPH and ATP utilization in the Calvin cycle, the thing that leads to the overproduction of ROS that severely damage the macromolecules of the cell [ 54 ].…”

Section: Discussionmentioning

confidence: 99%

Elevated CO2 Differentially Mitigated Oxidative Stress Induced by Indium Oxide Nanoparticles in Young and Old Leaves of C3 and C4 Crops

et al. 2022

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Soil contamination with indium (In) oxide nanoparticles (In2O3-NPs) threatens plant growth and development. However, their toxicity in plants under ambient (aCO2) and elevated (eCO2) conditions is scarcely studied. To this end, this study was conducted to investigate In2O3-NPs toxicity in the young and old leaves of C3 (barley) and C4 (maize) plants and to understand the mechanisms underlying the stress mitigating impact of eCO2. Treatment of C3 and C4 plants with In2O3-NPs significantly reduced growth and photosynthesis, induced oxidative damage (H2O2, lipid peroxidation), and impaired P and Fe homeostasis, particularly in the young leaves of C4 plants. On the other hand, this phytotoxic hazard was mitigated by eCO2 which improved both C3 and C4 growth, decreased In accumulation and increased phosphorus (P) and iron (Fe) uptake, particularly in the young leaves of C4 plants. Moreover, the improved photosynthesis by eCO2 accordingly enhanced carbon availability under the challenge of In2O3-NPs that were directed to the elevated production of metabolites involved in antioxidant and detoxification systems. Our physiological and biochemical analyses implicated the role of the antioxidant defenses, including superoxide dismutase (SOD) in stress mitigation under eCO2. This was validated by studying the effect of In2O3-stress on a transgenic maize line (TG) constitutively overexpressing the AtFeSOD gene and its wild type (WT). Although it did not alter In accumulation, the TG plants showed improved growth and photosynthesis and reduced oxidative damage. Overall, this work demonstrated that C3 was more sensitive to In2O3-NPs stress; however, C4 plants were more responsive to eCO2. Moreover, it demonstrated the role of SOD in determining the hazardous effect of In2O3-NPs.

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Heavy Metals and Photosynthesis: Recent Developments

Cited by 47 publications

References 156 publications

A Comprehensive Review on the Heavy Metal Toxicity and Sequestration in Plants

A Comprehensive Review on the Heavy Metal Toxicity and Sequestration in Plants

Melatonin induced changes in photosynthetic efficiency as probed by OJIP associated with improved chromium stress tolerance in canola (Brassica napus L.)

Elevated CO2 Differentially Mitigated Oxidative Stress Induced by Indium Oxide Nanoparticles in Young and Old Leaves of C3 and C4 Crops

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