Regulation of Photosynthesis Under Metal Stress

Khan, Mumtaz; Nawaz, Neeha; Azam, Muhammad; Rizwan, Muhammad; Ahmad, Parvaiz; Ali, Shafaqat

doi:10.1002/9781119501800.ch6

Cited by 21 publications

(14 citation statements)

References 42 publications

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“…In response to the heavy metal stress, photosynthetic efficiency reduces due to multiple reasons such as stress induced inhibition of enzymes for pigment biosynthesis in leaves, metal induced alterations in photosynthetic enzymes, reduced PSI and PSII activities, metal induced changes in the ion homeostasis and plant water imbalance [ 50 – 52 ]. Reduced chlorophyll content and photosynthetic efficiency were registered in the case of A .…”

Section: Discussionmentioning

confidence: 99%

Physio-anatomical modifications and elemental allocation pattern in Acanthus ilicifolius L. subjected to zinc stress

Sarath

Manzil²,

Ali

et al. 2022

PLoS ONE

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Physio-anatomical modifications and elemental distribution pattern in Acanthus ilicifolius subjected to Zn stress were analysed in this study. Survival of A. ilicifolius plants under a high concentration of ZnSO4 was compensated by the reduction in the photosynthetic efficacy. Micro and macro-elemental distribution pattern in the root tissues was significantly influenced by heavy metal exposure. Tolerance towards the excess toxic metal ions in the tissue of A. ilicifolius was aided by the modified anatomical features. Moreover, the increased deposition of Zn around the central vasculature of the root confirms the complexation of Zn2+ in the xylem vessels. Metal induced molecular level changes of root and leaf samples indicate the presence of OH, NH2, and CH3 deformation as well as C-O-H and C-O-C stretch. A prominent band corresponding to CH3 deformation, pointing hemicellulose fortification, occurs in the cell walls of the xylem, aiding in Zn localization. The phytostabilisation potential of A. ilicifolius is dependent on the coordinated responses which endow with phenotypic plasticity necessary to cope with Zn toxicity.

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Section: Discussionmentioning

confidence: 99%

Physio-anatomical modifications and elemental allocation pattern in Acanthus ilicifolius L. subjected to zinc stress

Sarath

Manzil²,

Ali

et al. 2022

PLoS ONE

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“…Conformational changes in chloroplasts upon Pb exposure were observed in terminal and median leaves of upland cotton. It is well established that chloroplasts have the inbuilt capacity to generate ROS; however, it is fortified under stress conditions (Khan et al, 2019). In addition, chloroplast proteome possesses reactive cysteines which are required for the catalytic functions of proteins and work under the control of glutaredoxin and thioredoxin systems (Zaffagnini et al, 2012;Couturier et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Reduced Glutathione Protects Subcellular Compartments From Pb-Induced ROS Injury in Leaves and Roots of Upland Cotton (Gossypium hirsutum L.)

et al. 2020

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Heavy metals-based changes in the plants and their alleviation through eco-friendly agents including reduced glutathione (GSH) have been widely studied. In the present experiment, we tested the alleviatory role of reduced glutathione (GSH) in seedlings of upland cotton cultivar, TM-1 under lead (Pb) toxicity. Plants were grown in the Hoagland solution containing Pb (0 µM), Pb (500 µM), GSH (50 µM), and GSH + Pb (50 µM + 500 µM). Lead exposure exacerbated hydrogen peroxide (H 2 O 2 ) and hydroxyl radical (OH • ) levels, induced lipid peroxidation (MDA), and decreased the activities of catalase (CAT) and ascorbate peroxidase (APX) in the terminal and median leaves of 28-days old cotton seedlings stressed for 10 days. However, in the primary and secondary roots, CAT activity was increased but APX decreased. Similarly, peroxidase (POD) and superoxide dismutase (SOD) activities were enhanced in the median leaves but a declining trend was observed in the terminal leaves, primary roots and secondary roots. Glutathione reductase (GR) activity, ascorbic acid (AsA) contents and GSH concentrations were increased in all parts except AsA in the median leaves. Transmission electron micrographs of Pb-treated plants exhibited deformed cell wall and cell membrane, disfigured chloroplasts and irregularly shaped mitochondria in the terminal and median leaves. Further, cell membrane, mitochondria, nucleus and other cell organelles in root cells were severely affected by the Pb. Thus their identification was little bit difficult through ultramicroscopy. External GSH stabilized leaf and root ultramorphology by stabilizing cell membranes, stimulating formation of multivesicular body vesicles, and by maintaining structural integrity of other organelles. Evidently, GSH played major alleviatory role against Pb toxicity in upland cotton.

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“…Cyanobacteria have specific needs for metals, which frequently differ from those of other bacteria-Mn 2+ is required for chlorophyll biosynthesis and for water-splitting oxygen-evolving complex, Cu 2+ for plastocyanin and cytochrome oxidase, Zn 2+ for DNA and RNA polymerases as well as for the carboxysome-localized carbonic anhydrase (for carbon assimilation), Co 2+ for vitamin B 12 biosynthesis and Mo 2+ for nitrogenase in heterocysts [12][13][14]. Those metals are considered as essential elements and required in trace amounts, while non-essential metals (e.g., Cd 2+ , Pb 2+ , Cr 2+ and Hg 2+ ) are toxic to cyanobacteria [13,14]. In addition, the essential metals are more generally required to provide defense against oxidative stresses, transfer electrons in photosynthetic reaction centers and serve as cofactors for metalloproteins.…”

Section: Introductionmentioning

confidence: 99%

“…Mostly affected is the photosynthetic machinery with alterations in the photosynthetic electron transport chain, several photosynthetic enzymes, dark reactions, ATP synthesis and photosynthetic pigments, leading to photoinhibition. For example, Pb 2+ , Mn 2+ and Cd 2+ can inhibit chlorophyll a and b biosynthesis [13,14].…”

Section: Introductionmentioning

confidence: 99%

“…As heavy metals are ubiquitous in the cyanobacterial biosphere, a proper control of metal homeostasis is, therefore, essential for the photosynthetic lifestyle of cyanobacteria. While nitrogen remains the growth-limiting factor, other environmental factors, such as heavy metals, could be toxic to the vegetative cells owing to their interference with vital intracellular processes [13,14]. However, it is unclear how they affect the cyanobacteria when they are in the dormant chlorotic state.…”

Section: Introductionmentioning

confidence: 99%

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Heavy Metal Stress Alters the Response of the Unicellular Cyanobacterium Synechococcus elongatus PCC 7942 to Nitrogen Starvation

Selim

Häffner

2020

Life

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Non-diazotrophic cyanobacteria are unable to fix atmospheric nitrogen and rely on combined nitrogen for growth and development. In the absence of combined nitrogen sources, most non-diazotrophic cyanobacteria, e.g., Synechocystis sp. PCC 6803 or Synechococcus elongatus PCC 7942, enter a dormant stage called chlorosis. The chlorosis process involves switching off photosynthetic activities and downregulating protein biosynthesis. Addition of a combined nitrogen source induces the regeneration of chlorotic cells in a process called resuscitation. As heavy metals are ubiquitous in the cyanobacterial biosphere, their influence on the vegetative growth of cyanobacterial cells has been extensively studied. However, the effect of heavy metal stress on chlorotic cyanobacterial cells remains elusive. To simulate the natural conditions, we investigated the effects of long-term exposure of S. elongatus PCC 7942 cells to both heavy metal stress and nitrogen starvation. We were able to show that elevated heavy metal concentrations, especially for Ni2+, Cd2+, Cu2+ and Zn2+, are highly toxic to nitrogen starved cells. In particular, cells exposed to elevated concentrations of Cd2+ or Ni2+ were not able to properly enter chlorosis as they failed to degrade phycobiliproteins and chlorophyll a and remained greenish. In resuscitation assays, these cells were unable to recover from the simultaneous nitrogen starvation and Cd2+ or Ni2+ stress. The elevated toxicity of Cd2+ or Ni2+ presumably occurs due to their interference with the onset of chlorosis in nitrogen-starved cells, eventually leading to cell death.

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Regulation of Photosynthesis Under Metal Stress

Cited by 21 publications

References 42 publications

Physio-anatomical modifications and elemental allocation pattern in Acanthus ilicifolius L. subjected to zinc stress

Physio-anatomical modifications and elemental allocation pattern in Acanthus ilicifolius L. subjected to zinc stress

Reduced Glutathione Protects Subcellular Compartments From Pb-Induced ROS Injury in Leaves and Roots of Upland Cotton (Gossypium hirsutum L.)

Heavy Metal Stress Alters the Response of the Unicellular Cyanobacterium Synechococcus elongatus PCC 7942 to Nitrogen Starvation

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