Evaluation of Arsenate- and Vanadate-Associated Changes of Electrical Membrane Potential and Phosphate Transport in<i>Lemna gibba</i>G1

Ullrich-Eberius, C. I.; Sanz, Ana Gimeno; Novacký, A.

doi:10.1093/jxb/40.1.119

Cited by 282 publications

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“…In contrast, the higher value of V max for A. caroliniana was in accordance with its higher ability of As accumulation, indicating that A. caroliniana may have a higher density of transporters on the plasma membranes that can transport arsenate. It has been well documented that arsenate is taken up through the phosphate transporters (Ullrich-Eberius et al, 1989;Abedin et al, 2002;Esteban et al, 2003). The relationship between As and P in the two strains of Azolla (Fig.…”

Section: Discussionmentioning

confidence: 95%

Arsenic accumulation by the aquatic fern Azolla: Comparison of arsenate uptake, speciation and efflux by A. caroliniana and A. filiculoides

Zhang

Lin

Zhao

et al. 2008

Environmental Pollution

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Arsenic accumulation and efflux differ between strains of the aquatic fern Azolla. This study investigates As accumulation and tolerance of the aquatic fern Azolla. Fifty strains of Azolla showed a large variation in As accumulation. The highest-and lowest-accumulating ferns among the 50 strains were chosen for further investigations. Azolla caroliniana accumulated two times more As than Azolla filiculoides owing to a higher influx velocity for arsenate. A. filiculoides was more resistant to external arsenate due to a lower uptake. Both strains showed a similar degree of tolerance to internal As. Arsenate and arsenite were the dominant As species in both Azolla strains, with methlyated As species accounting for <5% of the total As. A. filiculoides had a higher proportion of arsenite than A. caroliniana. Both strains effluxed more arsenate than arsenite, and the amount of As efflux was proportional to the amount of As accumulation. The potential of growing Azolla in paddy fields to reduce As transfer from soil and water to rice should be further evaluated. a r t i c l e i n f o

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Section: Discussionmentioning

confidence: 95%

Arsenic accumulation by the aquatic fern Azolla: Comparison of arsenate uptake, speciation and efflux by A. caroliniana and A. filiculoides

Zhang

Lin

Zhao

et al. 2008

Environmental Pollution

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“…This explanation may also apply to the higher As(V)% in phloem sap than in leaves. Phosphate is known to inhibit As(V) uptake (Ullrich-Eberius et al, 1989;Abedin et al, 2002;Wang et al, 2002), and may also inhibit As(V) loading into xylem or phloem. However, this latter effect was not observed in our experiment (Fig.…”

Section: Discussionmentioning

confidence: 99%

Arsenic Speciation in Phloem and Xylem Exudates of Castor Bean

et al. 2010

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How arsenic (As) is transported in phloem remains unknown. To help answer this question, we quantified the chemical species of As in phloem and xylem exudates of castor bean (Ricinus communis) exposed to arsenate [As(V)], arsenite [As(III)], monomethylarsonic acid [MMA(V)], or dimethylarsinic acid. In the As(V)-and As(III)-exposed plants, As(V) was the main species in xylem exudate (55%-83%) whereas As(III) predominated in phloem exudate (70%-94%). The ratio of As concentrations in phloem to xylem exudate varied from 0.7 to 3.9. Analyses of phloem exudate using high-resolution inductively coupled plasma-mass spectrometry and accurate mass electrospray mass spectrometry coupled to high-performance liquid chromatography identified high concentrations of reduced and oxidized glutathione and some oxidized phytochelatin, but no As(III)-thiol complexes. It is thought that As(III)-thiol complexes would not be stable in the alkaline conditions of phloem sap. Small concentrations of oxidized glutathione and oxidized phytochelatin were found in xylem exudate, where there was also no evidence of As(III)-thiol complexes. MMA(V) was partially reduced to MMA(III) in roots, but only MMA(V) was found in xylem and phloem exudate. Despite the smallest uptake among the four As species supplied to plants, dimethylarsinic acid was most efficiently transported in both xylem and phloem, and its phloem concentration was 3.2 times that in xylem. Our results show that free inorganic As, mainly As(III), was transported in the phloem of castor bean exposed to either As(V) or As(III), and that methylated As species were more mobile than inorganic As in the phloem.Arsenic (As) is an environmental and food chain contaminant that has attracted much attention in recent years. Soil contamination with As may lead to phytotoxicity and reduced crop yield (Panaullah et al., 2009). Food crops are also an important source of inorganic As, a class-one carcinogen, in human dietary intake, and there is a need to decrease the exposure to this toxin (European Food Safety Authority, 2009). Paddy rice (Oryza sativa) is particularly efficient in As accumulation, which poses a potential risk to the population based on a rice diet Zhao et al., 2010a). Other terrestrial food crops generally do not accumulate as much As as paddy rice; however, where soils are contaminated, relatively high concentrations of As in wheat (Triticum aestivum) grain have been reported Zhao et al., 2010b). On the other hand, some fern species in the Pteridaceae family are able to tolerate and hyperaccumulate As in the aboveground part to .1,000 mg kg 21 dry weight (e.g. Ma et al., 2001;Zhao et al., 2002); these plants offer the possibility for remediation of Ascontaminated soil or water (Salido et al., 2003;Huang et al., 2004). A better understanding of As uptake and long-distance transport, metabolism, and detoxification is needed for developing strategies for mitigating As contamination, through either decreased As accumulation in food crops or enhanced As accumulation for phytoremedi...

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“…Arsenate, the oxidized inorganic form of As, is taken up and translocated via the phosphate transporter systems (Asher and Reay, 1979;Lee, 1982;Ullrich-Eberius et al, 1989;Meharg and Macnair, 1992). The competition of uptake and translocation between phosphate and arsenate was shown in lots of plants (Chen et al, 2004;Liu et al, 2004;Rosa et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Effect of external and internal phosphate status on arsenic toxicity and accumulation in rice seedlings

Wang

Duan

2009

Journal of Environmental Sciences

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Phosphorus (P) deficiency is thought to exacerbate the arsenic (As) phytotoxicity in paddy rice. The experiments were conducted to investigate the effects of external phosphate supply on As accumulation in rice and its toxicity under phosphate deficiency conditions. Rice seedlings pretreated with a phosphorus deficient nutrient solution (-P) for 14 d accumulated more As than those pretreated with a normal phosphorus supply nutrient solution (+P). Rice protreated with -P showed As toxicity symptoms after being exposed to 50 μmol/L arsenate for 4 h, while +P rice did not show any toxicity symptoms. Arsenic toxicity symptoms can be alleviated by increasing external P concentrations. The arsenate uptake rate and accumulation corresponded with the As toxicity in rice plants. Arsenic concentrations in rice roots decreased with increasing external phosphate concentrations. The lowest As accumulation and the highest P accumulation were found when the external P concentration reached 100 μmol/L. In short, P deficiency increased the sensitivity of rice to arsenate and increasing of external phosphate supply could alleviate As toxicity.

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Evaluation of Arsenate- and Vanadate-Associated Changes of Electrical Membrane Potential and Phosphate Transport inLemna gibbaG1

Cited by 282 publications

References 0 publications

Arsenic accumulation by the aquatic fern Azolla: Comparison of arsenate uptake, speciation and efflux by A. caroliniana and A. filiculoides

Arsenic accumulation by the aquatic fern Azolla: Comparison of arsenate uptake, speciation and efflux by A. caroliniana and A. filiculoides

Arsenic Speciation in Phloem and Xylem Exudates of Castor Bean

Effect of external and internal phosphate status on arsenic toxicity and accumulation in rice seedlings

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