Metals (Fe, Mn, Zn) in the root plaque of submerged aquatic plants collected in situ: Relations with metal concentrations in the adjacent sediments and in the root tissue

St-Cyr, Louise; Campbell, Peter G. C.

doi:10.1007/bf00000969

Cited by 78 publications

(44 citation statements)

References 44 publications

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“…In fact, high concentrations of trace metals in the roots of aquatic plants have been reported for other environments (e.g. Otte et al 1989;Otte 1991;St-Cyr and Campbell 1996;St-Cyr and Crowder 1990). Could it be that pioneer plants such as S. maritima not only have developed mechanisms for oxidizing anoxic sediments, thereby reducing the uptake of the reduced species of Fe, Mn, and S, but that they also have developed mechanisms for immobilizing and rendering harmless other toxic metals within their root tissue?…”

Section: Discussionmentioning

confidence: 91%

Metal‐rich concretions on the roots of salt marsh plants: Mechanism and rate of formation

Sundby

Vale

Caçador

et al. 1998

Limnology & Oceanography

130

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The roots of the vascular plant Spartina maritima, growing in the saltmarshes of the Tagus Estuary, Portugal, are surrounded by tubular concretions whose diameter can reach >0.2 cm. Concretions are also found scattered within the sediment matrix in and below the root zone. The concretions comprise 4% (DW) of the sediment and contain 11.7 2 1.6% iron compared to 4.9 -C 0.3% iron in the sediment in which they are found. They are formed by the precipitation of iron oxides in the pores between the sediment grains; this has filled about one-sixth of the originally available pore space. To produce the concretions, the plants have extracted 0.25% Fe from the anoxic bulk sediment and concentrated it into the oxidized microenvironment surrounding each root. A mass-balance model using cylindrical geometry shows that the observed concretion density can be produced by a network of roots with l-cm spacing. The space between the roots limits the amount of Fe that is available to a given root and thus determines the size of the individual concretion. Field observations and mathematical modeling show that plants can produce concretions on their roots in the space of a few weeks. The rhizoconcretions are 5-10 times enriched in Cd, Cu, Pb, and Zn with respect to the sediment surrounding them, and the smaller diameter concretions are more enriched than the larger ones. The preferential enrichment of the smaller diameter concretions, which was not observed for Fe and Mn, is independent of depth in the sediment for Cd and Cu; however, for Zn and Pb, the preferential enrichment is most pronounced within the upper trace metal-contaminated sediment layer. The rhizoconcretions have acquired their load of metals via diffusion from the surrounding sediment. In the case of Fe and Mn, the concentration gradient that drives the diffusion is maintained by the precipitation of insoluble oxides. In the case of Cd, Cu, Zn, and Pb, the mechanism that maintains a concentration gradient toward the surface of the root is not know, but our data show that S. maritima is capable of mobilizing trace metals dispersed in reducing anoxic estuarine sediment and concentrating them into the distinct oxidized microenvironments that surround the roots.

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Section: Discussionmentioning

confidence: 91%

Metal‐rich concretions on the roots of salt marsh plants: Mechanism and rate of formation

Sundby

Vale

Caçador

et al. 1998

Limnology & Oceanography

130

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“…As reduções, em ordem decrescente, foram nas raízes > caule > folhas. Resultados semelhantes foram relatados para P, Mn e Zn em arroz (SILVEIRA et al, 2007) e Mn, Zn e Cu em Phragmites australis (ST-CYR;CAMPBELL, 1996). O excesso de Fe pode induzir deficiências minerais de P, K, Ca, Mg e Zn, resultando em desordens nutricionais múltiplas (BENCKISER et al, 1984 (HOWELLER, 1973), inibindo a absorção, transporte e/ou utilização de vários minerais (FAGERIA et al, 2008).…”

Section: Resultsunclassified

“…Grande parte das alterações nutricionais está relacionada à formação da chamada "placa de ferro" na superfície radicular (CHEN et al, 2006;ST-CYR;CAMPBELL, 1996). Essas placas, constituídas de óxidos e hidróxidos de ferro, apresentam elevada capacidade para adsorver diferentes minerais (LIU et al, 2008;ZHANG;ZHANG;MAO, 1999), atuando como barreira à absorção de determinados nutrientes.…”

Section: Introductionunclassified

Excess iron on growth and mineral composition inEugenia unifloraL.

Jucoski

Cambraia

Ribeiro

et al. 2016

Revista Ciência Agronômica

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Excesso de ferro sobre o crescimento e a composição mineral emEugenia uniflora L. 1Excess iron on growth and mineral composition in Eugenia uniflora L. ABSTRACT -Iron, although an essential micronutrient, when present in excess can cause a reduction in the growth, and hence the productivity, of plants. The aim of this study was to evaluate the absorption, accumulation and distribution of Fe, and its consequences on growth and mineral composition in young plants of Eugenia uniflora L.. The plants were exposed to different concentrations of Fe, 0.045 (control), 1.0 and 2.0 mM, applied in the form of Fe-EDTA in Hoagland's pH 5.0 nutrient solution for 15, 30 and 45 days, when the number of leaves, shoot height, primary root length, dry mass of the roots, stems and leaves, and the levels of chlorophyll, total carotenoids and minerals were evaluated. Plants exposed to the treatments with 1.0 and 2.0 mM Fe showed an increase in levels of the element in the leaves, stem and roots, compared to the control plants, especially after 45 days of exposure. Under that condition, the plants exhibited typical symptoms of Fe toxicity, characterised by leaf bronzing, darkening of the roots, a reduction in the number of leaves, shoot height, length of the main root, dry matter production and the levels of chloroplast pigments. Excess Fe modified biomass partitioning and caused a reduction in the levels of P, Zn, Cu and Mn, especially in the roots. In addition to the direct effect of excess Fe, the resulting nutritional disorder may be associated with restrictive effects on initial vegetative growth in plants of Eugenia uniflora L..

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“…1c). This suggests that the precipitates are engulfed in the root epidermis (Cotter-Howells et al, 1999) and do not coat the root surface as iron and manganese plaques do (Otte et al, 1989;St-Cyr and Campbell, 1996). No differences were observed among precipitates from plants grown in the untreated and mineral amended sediments.…”

Section: Optical and Electron Microscopymentioning

confidence: 95%

Formation of Zn–Ca phyllomanganate nanoparticles in grass roots

Lanson

Marcus

Fakra

et al. 2008

Geochimica et Cosmochimica Acta

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International audienceIt is now well established that a number of terrestrial and aquatic microorganisms have the capacity to oxidize and precipitate Mn as phyllomanganate. However, this biomineralization has never been shown to occur in plant tissues, nor has the structure of a natural Mn(IV) biooxide been characterized in detail. We show that the graminaceous plant Festuca rubra (red fescue) produces a Zn-rich phyllomanganate with constant Zn:Mn and Ca:Mn atomic ratios (0.46 and 0.38, respectively) when grown on a contaminated sediment. This new phase is so far the Zn-richest manganate known to form in nature (chalcophanite has a Zn:Mn ratio of 0.33) and has no synthetic equivalent. Visual examination of root fragments under a microscope shows black precipitates about ten to several tens of microns in size, and their imaging with backscattered and secondary electrons demonstrates that they are located in the root epidermis. In situ measurements by Mn and Zn K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy and X-ray diffraction (XRD) with a micro-focused beam can be quantitatively described by a single-phase model consisting of Mn(IV) octahedral layers with 22% vacant sites capped with tetrahedral and octahedral Zn in proportions of 3:1. The layer charge deficit is also partly balanced by interlayer Mn and Ca. Diffracting crystallites have a domain radius of 33 Å in the ab plane and contain only 1.2 layers (not, vert, similar8.6 Å) on average. Since this biogenic Mn oxide consists mostly of isolated layers, basal 00l reflections are essentially absent despite its lamellar structure. Individual Mn layers are probably held together in the Mn–Zn precipitates by stabilizing organic molecules. Zinc biomineralization by plants likely is a defense mechanism against toxicity induced by excess concentrations of this metal in the rhizosphere

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Metals (Fe, Mn, Zn) in the root plaque of submerged aquatic plants collected in situ: Relations with metal concentrations in the adjacent sediments and in the root tissue

Cited by 78 publications

References 44 publications

Metal‐rich concretions on the roots of salt marsh plants: Mechanism and rate of formation

Metal‐rich concretions on the roots of salt marsh plants: Mechanism and rate of formation

Excess iron on growth and mineral composition inEugenia unifloraL.

Formation of Zn–Ca phyllomanganate nanoparticles in grass roots

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