Inhibition of the Chloroplast Photochemical Reactions by Treatment of Wheat Seedlings with Low Concentrations of Cadmium: Analysis of Electron Transport Activities and Changes in Fluorescence Yield

Atal, Neelima; Saradhi, P. Pardha; Mohanty, Prasanna

doi:10.1093/oxfordjournals.pcp.a078181

Cited by 136 publications

(89 citation statements)

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“…However, in agreement with our finding, although not discussed in the article, their in vivo fluorescence measurements of the green alga Chlamydomonas reinhardtii appear to show an acceleration of reconstitution of PSII activity with the addition of Cd 2C , even though maximum activity is decreased. Other published studies have reported IC 50 values in the low micromolar range for Cd 2C inhibition of O 2 evolution in a few plants, algae and cyanobacteria (Stobart et al 1985;Ata et al 1991;Schafer et al 1994;Nagel & Voigt 1995;Okamoto et al 1996). Although these measurements did not distinguish between PSII inhibition during photoactivation or functional PSII, it is likely that Cd 2C binding during photoactivation played a more important role than Cd 2C binding to functional PSII.…”

Section: Discussionmentioning

confidence: 76%

Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn ₄ Ca core

Bartlett

Baranov

Ananyev

et al. 2007

Phil. Trans. R. Soc. B

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Perturbation of the catalytic inorganic core (Mn 4 Ca 1 O x Cl y ) of the photosystem II-water-oxidizing complex (PSII-WOC) isolated from spinach is examined by substitution of Ca 2C with cadmium(II ) during core assembly. Cd 2C inhibits the yield of reconstitution of O 2 -evolution activity, called photoactivation, starting from the free inorganic cofactors and the cofactor-depleted apo-WOC-PSII complex. Ca 2C affinity increases following photooxidation of the first Mn 2C to Mn 3C bound to the 'high-affinity' site. Ca 2C binding occurs in the dark and is the slowest overall step of photoactivation (IM 1 /IM 1 Ã step). Cd 2C competitively blocks the binding of Ca 2C to its functional site with 10-to 30-fold higher affinity, but does not influence the binding of Mn 2C to its high-affinity site. By contrast, even 10-fold higher concentrations of Cd 2C have no effect on O 2 -evolution activity in intact PSII-WOC. Paradoxically, Cd 2C both inhibits photoactivation yield, while accelerating the rate of photoassembly of active centres 10-fold relative to Ca 2C

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Section: Discussionmentioning

confidence: 76%

Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn ₄ Ca core

Bartlett

Baranov

Ananyev

et al. 2007

Phil. Trans. R. Soc. B

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“…The reaction mixture for assaying PSII activity consisted of 50 mM HEPES buffer (pH 7.5) containing 400 mM sucrose, 5 mM MgCl 2 , and 10 mM NaCl in a final volume of 1 mL. The activity was measured as oxygen evolution with water as electron donor and 500 µM phenyl p-benzoquinone (pBQ) as the electron acceptor (Atal et al, 1991). For measurement of PSI-mediated electron transport, the reaction mixture consisted of assay buffer along with 5 µM DCMU, 100 µM dichlorophenol indophenol (DCPIP), 1 mM ascorbate, 500 µM methyl viologen and 1 mM sodium azide (Atal et al, 1991).…”

Section: Photosynthetsis In Salvinia Exposed To Chromium and Zinc Ricmentioning

confidence: 99%

“…The activity was measured as oxygen evolution with water as electron donor and 500 µM phenyl p-benzoquinone (pBQ) as the electron acceptor (Atal et al, 1991). For measurement of PSI-mediated electron transport, the reaction mixture consisted of assay buffer along with 5 µM DCMU, 100 µM dichlorophenol indophenol (DCPIP), 1 mM ascorbate, 500 µM methyl viologen and 1 mM sodium azide (Atal et al, 1991). The chlorophyll content in thylakoids was estimated according to Arnon (1949).…”

Section: Photosynthetsis In Salvinia Exposed To Chromium and Zinc Ricmentioning

confidence: 99%

Photosynthetic performance of Salvinia natans exposed to chromium and zinc rich wastewater

Dhir

Sharmila

Saradhi

2008

Braz. J. Plant Physiol.

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Investigations were carried out to evaluate alterations in photosynthetic performance of Salvinia natans (L.) exposed to chromium (Cr) and zinc (Zn) rich wastewater. Accumulation of high levels of Cr and Zn in plants affected photosynthetic electron transport. Photosystem-(PS) II-mediated electron transport was enhanced in plants exposed to Cr rich wastewater while a decline was observed in Zn-exposed plants. Photosystem-I-mediated electron transport increased in plants exposed to Cr and Zn rich wastewater. Efficiency of photosystem II (F v /F m ) measured by fluorescence did not show any significant change in Cr-exposed plants but a decrease was observed in Zn-exposed plants as compared to the control. The enhancement in PS I-induced cyclic electron transport in Cr and Zn exposed plants led to a build up of the transthylakoidal proton gradient (∆pH) which subsequently helped in maintaining the photophosphorylation potential to meet the additional requirement of ATP under stress. The carbon assimilation potential was adversely affected as evident from the decrease in Rubisco (EC 4.1.1.39) activity. The alterations in photosynthetic electron transport affected stromal redox status and induced variations in the level of stromal components such as pyridine nucleotides in plants exposed to Cr and Zn rich wastewater. The present investigations revealed that alteration in the photosynthetic efficiency of Salvinia exposed to Cr could primarily be the result of a decline in carbon assimilation efficiency relative to light-mediated photosynthetic electron transport, though in the case of Zn-exposed plants both these factors were affected equally. Key words: carbon assimilation, electron transport, heavy metals, photophosphorylation, redox status Desempenho fotossintético de plantas de Salvinia natans expostas a água de esgoto rica em cromo e zinco: Avaliou-se o desempenho fotossintético de plantas de Salvinia natans L. expostas a água de esgoto rica em cromo (Cr) e zinco (Zn). O acúmulo de Cr e Zn em altos níveis afetou o transporte fotossintético de elétrons. O transporte de elétrons mediado pelo fotossistema (FS) II aumentou nas plantas expostas ao esgoto rico em Cr, observando-se o oposto nas plantas expostas ao esgoto rico em Zn. O transporte de elétrons mediado pelo FS I aumentou nas plantas expostas ao esgoto rico tanto em Cr como em Zn. A eficiência do FS II (F v /F m ) avaliada por fluorescência não variou significativamente em resposta ao Cr, porém reduziu-se nas plantas expostas ao esgoto rico em Zn, em comparação com as plantas-controle. O aumento do transporte cíclico de elétrons associado ao FS I acarretou em aumento do gradiente transtilacoidal de prótons (∆pH) que, por seu turno, esteve associado com o potencial de fotofosforilação para suportar as necessidades adicionais de ATP sob condições de estresse. O potencial de assimilação do carbono foi decrescido, conforme se deduz da menor atividade da Rubisco (EC 4.1.1.39). As alterações no transporte fotossintético de elétrons afetaram o status redox do estro...

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“…Human activities have drastically altered the biochemical and geochemical cycles and balance of some heavy metals. In the early seventeenth, several researchers carried out series of investigations to enhance the quality of water using natural means (2)(3)(4)(5). Since then extensive research is being proceeded worldwide by numerous investigators to study the performance of many species of aquatic plants in removal of nutrients and metals in different aquatic water bodies (Dana Ahmed 2014) among different varieties of plant, the concept of using aquatic plant are experimentally acknowledged to mitigate a considerable amount of pollutants time, organic contaminants, metals from aquatic environment through absorption, and / or adsorption to incorporate then directly into their plant tissues.…”

Section: Issn: 2320-5407mentioning

confidence: 99%

An Assessment of Heavy Metal Accumulation Capacity of Five Aquatic Macrophytes and Biochemical Response.

KS¹,

Mathew²,

RameshBabuM³

2017

IJAR

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The phytoextraction capacity of five aquatic macrophytes (Eichhorniacrassipes,Hydrillaverticellata Pistia stratioties, Salviniamolesta and Lagenandra toxicaria) with respect to heavy metals like Ni, As, Zn, Cr and Fe were studied. It was done to study the plants capacity comparatively using monometallic system. Inorder to assess the biochemical response of the studied plants to heavy metal stress, metabolites like total carbohydrates, total soluble protein, tannin, total carotenoids, alkaloids, flavanoids, terpenoids, saponin and phenol were quantitatively estimated before and after treatment. With regard to Ni, As and Fe sample II showed maximum absorption and least by sample V. Zn absorption is greatest in plant sample II and least in sample I. As with Cr plant sample IV showed maximum absorption and least by sample I. The most significant biochemical change observed is the substantial increase in quantity of total carbohydrate, total soluble protein, total carotenoids, saponin and phenol content of the treated plants. Similarly there is a substantial reduction in metabolites like tannin, alkaloids, flavanoids and terpenoids after treatment. The studied macrophytes proved to the useful in the uptake of heavy metals in the monometallic system and showed great of potential for further applications in the industrial and waste water treatments.Copy Right, IJAR, 2017,. All rights reserved. …………………………………………………………………………………………………….... Introduction:-General contamination of heavy metals in the environment is a major global concern, which has provoked the emergence of phytpremediation technologies for cleaning aquatic environment. Heavy metals are released into the environment from a wide range of natural and anthropogenic sources. Aquatic systems often act as final receptacles to these metals whose concentration in interstitial water might increase several thousand folds by effluents from water (Bastian and Hammer 1993). Heavy metals are strong environmental pollutants and many of them are toxic, even at very low concentrations. Contrary to organic materials, they cannot be degraded and therefore they accumulate in water, bottom sediment and living organisms.Heavy metals are the stable metals or metalloids whose density is greater than 5g/cm3, namely mercury, cadmium, cobalt, lead, molybdenum, nickel, copper, zinc etc(Nies 1999). Heavy metals are natural constituents of the Earth's

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Inhibition of the Chloroplast Photochemical Reactions by Treatment of Wheat Seedlings with Low Concentrations of Cadmium: Analysis of Electron Transport Activities and Changes in Fluorescence Yield

Cited by 136 publications

References 30 publications

Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn ₄ Ca core

Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn ₄ Ca core

Photosynthetic performance of Salvinia natans exposed to chromium and zinc rich wastewater

An Assessment of Heavy Metal Accumulation Capacity of Five Aquatic Macrophytes and Biochemical Response.

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Inhibition of the Chloroplast Photochemical Reactions by Treatment of Wheat Seedlings with Low Concentrations of Cadmium: Analysis of Electron Transport Activities and Changes in Fluorescence Yield

Cited by 136 publications

References 30 publications

Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn 4 Ca core

Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn 4 Ca core

Photosynthetic performance of Salvinia natans exposed to chromium and zinc rich wastewater

An Assessment of Heavy Metal Accumulation Capacity of Five Aquatic Macrophytes and Biochemical Response.

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Product

Resources

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Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn ₄ Ca core

Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn ₄ Ca core