Ascorbate promotes emission of mercury vapour from plants

Battke, Florian; Ernst, D.; Halbach, Stefan

doi:10.1111/j.1365-3040.2005.01385.x

Cited by 30 publications

(17 citation statements)

References 31 publications

(63 reference statements)

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“…Reduction of Hg(II) to Hg(0) in the leaves with transpiration of Hg(0) as a consequence was also observed . Ionic Hg(II) is carried by the transpiration flow from roots to leaves and then reduced to Hg(0) in the apoplastic spaces of the spongy mesophyll by ascorbic acid . Although the putative reduction with ascorbic acid has been described in barley, authors suggested that reduction of Hg(II) to Hg(0) occurs in macrophytes .…”

Section: Effects Of Shootsmentioning

confidence: 97%

“…On the contrary, in I. aquatica , an exposure to HgCl 2 ‐spiked nutrient medium for a period of 4 d, followed by 4 d without any addition of external Hg, resulted in a 3‐fold increase of MeHg concentrations in the shoots as compared with levels directly after the Hg exposure, suggesting methylation of Hg in planta . Reduction of Hg(II) to Hg(0) in the leaves with transpiration of Hg(0) as a consequence was also observed . Ionic Hg(II) is carried by the transpiration flow from roots to leaves and then reduced to Hg(0) in the apoplastic spaces of the spongy mesophyll by ascorbic acid .…”

Section: Effects Of Shootsmentioning

confidence: 98%

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Effects of macrophytes on the fate of mercury in aquatic systems

Cosio

Flück

Regier

et al. 2014

Enviro Toxic and Chemistry

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Vegetated and shallow areas such as wetlands and salt marshes, as well as freshwater lakes and rivers, have been identified as hotspots for Hg methylation. The presence of aquatic macrophytes, the predominant primary producers in shallow waters, plays an important but still poorly understood role in the fate of Hg in these environments. The present review focuses on the influences of macrophytes on Hg speciation and distribution in sediments, the rhizosphere, and the water column; on Hg transformation; and on Hg release to the environment, including transfer to the trophic web. Future research will require an improved understanding of the mechanisms and the factors controlling these aspects as well as a broader general view. Thus, the main gaps in knowledge are also discussed.

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Section: Effects Of Shootsmentioning

confidence: 97%

Section: Effects Of Shootsmentioning

confidence: 98%

Effects of macrophytes on the fate of mercury in aquatic systems

Cosio

Flück

Regier

et al. 2014

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

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“…Laboratory evidence has shown that plants (53)(54)(55), fungi (23,56,57), bacteria (58), and algae (59) can transform other more easily reducible metals, including Au, Ag, Se (as H2SeO3), Hg, and Te, to their elemental states both intraand extracellularly. When mechanisms have been proposed, they typically have involved enzymes; however, ascorbic acid was implicated when Hg 2+ was transformed to Hg 0 (g) in barley leaves (60). Theoretically all of these metal cations could be transformed by a reducing agent weaker than ascorbic acid (Table S1 in Supporting Information).…”

Section: Mechanism Of Cumentioning

confidence: 99%

Formation of Metallic Copper Nanoparticles at the Soil−Root Interface

Manceau

Nagy

Marcus

et al. 2008

Environ. Sci. Technol.

222

117

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Copper is an essential element in the cellular electron-transport chain, but as a free ion it can catalyze production of damaging radicals. Thus, all life forms attempt to prevent copper toxicity. Plants diminish excess copper in two structural regions: rare hyperaccumulators bind cationic copper to organic ligands in subaerial tissues, whereas widespread metal-tolerant plants segregate copper dominantly in roots by mechanisms thought to be analogous. Here we show using synchrotron microanalyses that common wetlands plants Phragmites australis and Iris pseudoacorus can transform copper into metallic nanoparticles in and near roots with evidence of assistance by endomycorrhizal fungi when grown in contaminated soil in the natural environment. Biomolecular responses to oxidative stress, similar to reactions used to abiotically synthesize Cu0 nanostructures of controlled size and shape, likely cause the transformation. This newly identified mode of copper biomineralization by plant roots under copper stress may be common in oxygenated environments.

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“…st is an empirical input value and suggested as 5-25 ng m −3 depending on the specific land use. Battke et al (2005Battke et al ( , 2008 and Heaton et al (2005) reported that plants have the ability to reduce the Hg II to Hg 0 in foliar cells through reducing ligands (e.g., NADPH). To propose a more physically robust modeling scheme, the redox processes in foliage and the role of ligands on Hg uptake need to be better understood.…”

Section: Modeling Of Air-surface Hg 0 Exchange Fluxmentioning

confidence: 99%

Global observations and modeling of atmosphere–surface exchange of elemental mercury: a critical review

et al. 2016

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Abstract. Reliable quantification of air-surface fluxes of elemental Hg vapor (Hg 0 ) is crucial for understanding mercury (Hg) global biogeochemical cycles. There have been extensive measurements and modeling efforts devoted to estimating the exchange fluxes between the atmosphere and various surfaces (e.g., soil, canopies, water, snow, etc.) in the past three decades. However, large uncertainties remain due to the complexity of Hg 0 bidirectional exchange, limitations of flux quantification techniques and challenges in model parameterization. In this study, we provide a critical review on the state of science in the atmosphere-surface exchange of Hg 0 . Specifically, the advancement of flux quantification techniques, mechanisms in driving the air-surface Hg exchange and modeling efforts are presented. Due to the semi-volatile nature of Hg 0 and redox transformation of Hg in environmental media, Hg deposition and evasion are influenced by multiple environmental variables including seasonality, vegetative coverage and its life cycle, temperature, light, moisture, atmospheric turbulence and the presence of reactants (e.g., O 3 , radicals, etc.). However, the effects of these processes on flux have not been fundamentally and quantitatively determined, which limits the accuracy of flux modeling.We compile an up-to-date global observational flux database and discuss the implication of flux data on the global Hg budget. Mean Hg 0 fluxes obtained by micrometeorological measurements do not appear to be significantly greater than the fluxes measured by dynamic flux chamber methods over unpolluted surfaces (p = 0.16, one-tailed, Mann-Whitney U test). The spatiotemporal coverage of existing Hg 0 flux measurements is highly heterogeneous with large data gaps existing in multiple continents (Africa, South Asia, Middle East, South America and Australia). The magnitude of the evasion flux is strongly enhanced by human activities, particularly at contaminated sites. Hg 0 flux observations in East Asia are comparatively larger in magnitude than the rest of the world, suggesting substantial re-emission of previously deposited mercury from anthropogenic sources. The Hg 0 exchange over pristine surfaces (e.g., background soil and water) and vegetation needs better constraints for global analyses of the atmospheric Hg budget. The existing knowledge gap and the associated research needs for future measurements and modeling efforts for the air-surface exchange of Hg 0 are discussed.

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Ascorbate promotes emission of mercury vapour from plants

Abstract: ABSTRACT

Cited by 30 publications

References 31 publications

Effects of macrophytes on the fate of mercury in aquatic systems

Effects of macrophytes on the fate of mercury in aquatic systems

Formation of Metallic Copper Nanoparticles at the Soil−Root Interface

Global observations and modeling of atmosphere–surface exchange of elemental mercury: a critical review

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