Rhizotoxic effects of silver in cowpea seedlings

Blamey, F. P. C.; Kopittke, Peter M.; Wehr, Bernhard; Kinraide, Thomas B.; Menzies, Neal W.

doi:10.1002/etc.236

Cited by 17 publications

(24 citation statements)

References 27 publications

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“…Using this experimental system, dose-response curves were determined from studies of 11 metals published from work in this laboratory for Ag(I) [6], Al(III), Cu(II), and La(III) [5], Pb(II) (P.M. Kopittke, University of Queensland, St Lucia, Queensland, Australia, unpublished data), and Ga(III), Gd(III), Hg(II), In(III), Ru(III), and Sc(III) [7]. Additional experiments using the same system were conducted for Ba(II), Ca(II), Cd(II), Cs(I), Co(II), H(I), K(I), Li(I), Mg(II), Mn(II), Na(I), Ni(II), Sr(II), Tl(I), and Zn(II).…”

Section: Methodsmentioning

confidence: 99%

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Toxicity of metals to roots of cowpea in relation to their binding strength

Kopittke

Blamey

McKenna

et al. 2011

Enviro Toxic and Chemistry

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Metal phytotoxicity is important in both environmental and agricultural systems. A solution culture study examined the toxicity of 26 metals to roots of cowpea (Vigna unguiculata (L.) Walp.); new data were collected for 15 metals and published data for 11 metals. Metal toxicity, calculated as causing a 50% reduction in root elongation rate, was determined based on either the measured concentration in the bulk solution (EC50(b)) or the calculated activity at the outer surface of the plasma membrane (EA50(0)°). The EC50(b) values ranged from 0.007 µM for Tl to 98,000 µM for K, with the order of rhizotoxicity to cowpea, from most to least toxic, being Tl = Ag > Cu > Hg = Ni = Ga = Ru = In > Sc = Cd = Gd = La = Co = Cs = Pb > Zn = Al = H > Mn > Ba = Sr > Li > Mg > Ca = Na > K. The EA50(0)° values suggest that the binding of metals to hard ligands is an important, general, nonspecific mechanism of toxicity, a hypothesis supported by the similar toxicity symptoms to roots of cowpea by many metals. However, additional mechanisms, such as strong binding to soft ligands, substantially increase rhizotoxicity of some metals, especially Tl, Ag, and Cs. Besides direct toxic effects, osmotic effects or reduced activity of Ca(2+) at the outer surface of the root plasma membrane (and resultant Ca deficiency) may decrease short-term root growth.

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Section: Methodsmentioning

confidence: 99%

“…Each point is the mean of two replicates. Data are from the current and previous studies [5][6][7]. The values and 95% confidence intervals for all coefficients are reported in the Supplemental Data, Table S2.…”

Section: Root Growth and Metal Toxicitymentioning

confidence: 98%

Toxicity of metals to roots of cowpea in relation to their binding strength

Kopittke

Blamey

McKenna

et al. 2011

Enviro Toxic and Chemistry

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“…3 and 4). These ruptures have been reported previously for a range of plant species, including for toxicities of Ag, Al, Cu, La, Ga, Gd, Hg, In, Ru, and Sc (Blamey et al 2010;Kopittke et al 2009;Matsumoto and Motoda 2012;Osawa et al 2011;Sheldon and Menzies 2005). For Al, this rupturing is associated with an inhibition of wall loosening for the outer cells of the root cylinder in which the Al binds strongly to the cell wall (Kopittke et al 2015).…”

Section: Changes In Root Morphologymentioning

confidence: 92%

“…Although some metals are better understood than others, much remains unknown regarding the kinetics (speed) with which various metals reduce growth, the nature of this growth reduction, and the changes in root morphology (symptoms) associated with short-term exposure. For example, considering changes in root morphology, a range of metals have been found to cause the rupturing (tearing) of the outer tissues of the root cylinder in a variety of plant species, including Ag, Al, Cu, La, Ga, Gd, Hg, In, Ru, and Sc (Blamey et al 2010;Kopittke et al 2009;Matsumoto and Motoda 2012;Osawa et al 2011). In addition, Al toxicity has been reported cause swelling of epidermal cells in wheat (Triticum aestivum) (Kinraide 1988).…”

Section: Introductionmentioning

confidence: 99%

Kinetics of metal toxicity in plant roots and its effects on root morphology

Kopittke

Wang

2017

Plant Soil

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Aims Elevated levels of metals reduce plant growth, including contaminated, acid, and saline soils, but much remains unknown regarding their mechanisms of toxicity. In this regard, it is important to understand the kinetics of changes in root elongation rate (RER) and root morphology. Methods Seedlings of soybean (Glycine max) were grown in solutions containing toxic levels of one of seven metals that differed markedly in their properties (Ag, Al, Ca, Cu, Hg, Na, and Sr), with mannitol and 'mixed salts' treatments also included. Results Despite their widely differing properties, all treatments caused similar symptoms, with roots swelling radially within the elongation zone, possibly associated with ethylene or auxin. In addition, Ag, Al, Cu, and Hg caused a rupturing of the outer root tissues likely associated with inhibition of wall loosening. Finally, using kinematic analyses to examine the effects of Hg in 5 min intervals, it was found that RER decreased by 50% after only 40 min, primarily associated with a decrease in the rate at which individual cells were elongating. Conclusions The information provided here will assist in understanding the mechanisms by which toxic levels of metals reduce root elongation.

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“…The presence of Ag in the environment is of concern because of its potential toxicity to a range of organisms such as plants, invertebrates, microbes and bacteria living in the soil. [12][13][14][15][16] In comparison to aquatic environments, there has been limited research undertaken on the fate and behaviour of Ag in soil. The predicted increase in Ag concentrations (e.g.…”

Section: Introductionmentioning

confidence: 99%

A method to determine silver partitioning and lability in soils

et al. 2014

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Environmental context. Soils contaminated with silver can have detrimental environmental effects because of silver's toxicity to a range of soil-dwelling organisms. The total concentration of silver in soil, however, is often not a good indicator of potential toxicity as it does not account for variations in bioavailability. We report a method for soil analysis that measures the amount of silver available for uptake by soil-dwelling organisms, and hence could provide data that better reflect potential toxicity.Abstract. There is increasing potential for pollution of soils by silver because of an increased use of this metal in consumer and industrial products. Silver may undergo reactions with soil components that mitigate its availability and potential toxicity, so that the total concentration of this metal in soil is not a useful indicator of potential risk. We developed an isotopic dilution method to simultaneously measure the partitioning (K d -value) and lability (E-value) of Ag in soils, using the 110m Ag isotope. An equilibration solution containing 10 mM Ca(NO 3 ) 2 was used along with a cation exchange resin to correct for possible interferences from non-isotopically exchangeable Ag associated with soil colloids in suspension (E r -value). The quantification limits for K d and E r will depend on the amounts of radioisotope spiked and daily detection limits of inductively coupled plasma-mass spectrometry instrumentation but are typically .4000 L kg À1 and ,0.92 mg kg À1 . Measurement of K d values for Ag in a range of soils indicated strong partitioning to the solid phase is positively associated with soil cation-exchange capacity or total organic carbon and pH. The concentrations of labile Ag in soils geogenically enriched in Ag were not detectable indicating occlusion of the Ag within poorly soluble solid phases. Measurement of labile Ag in soils spiked with a soluble Ag salt and aged for 2 weeks indicated rapid conversion of soluble Ag into non-isotopically exchangeable forms, either irreversibly adsorbed or precipitated in the soil. These results indicate that measurement of labile Ag will be important to estimate toxicity risks to soil organisms or to predict bioaccumulation through the food chain.

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Rhizotoxic effects of silver in cowpea seedlings

Cited by 17 publications

References 27 publications

Toxicity of metals to roots of cowpea in relation to their binding strength

Toxicity of metals to roots of cowpea in relation to their binding strength

Kinetics of metal toxicity in plant roots and its effects on root morphology

A method to determine silver partitioning and lability in soils

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