Phosphate and arsenate interactions in the rhizosphere of canola (Brassica napus).

Arsenate [As(V)] and phosphate [P(V)] compete for the same uptake systems in plant roots. For this reason, P(V) is often added to As-contaminated soils to reduce As(V) uptake and alleviate As toxicity. However, the addition of P(V) can result in an increase in As concentrations in plant tissues, which is often attributed to an increase in As(V) availability, although direct evidence for this explanation is lacking. Rhizosphere and batch desorption experiments were conducted to investigate (i) the effect of As(V) and P(V) additions, and plant phosphorus (P) status, on As(V) uptake by canola (Brassica napus L.) and (ii), P(V) and As(V) interactions at the surface of roots and specific soil particles (goethite and kaolinite). Results showed that P-deficient canola took up more As(V) from arsenated kaolinite, but transported less As from roots to shoots, than P-adequate canola. The addition of P(V) adsorbed on substrate increased As(V) uptake by canola but desorption experiments revealed that the addition of phosphated kaolinite to arsenated kaolinite was not likely to increase As(V) availability in the rhizosphere. It was concluded that plant P status together with P(V) and As(V) interactions at the surfaces of roots and soil particles need to be considered to properly asses P(V) and As(V) interactions in the plant-soil continuum.

[1]  A. Meharg,et al.  High-affinity phosphate/arsenate transport in white lupin (Lupinus albus) is relatively insensitive to phosphate status , 2003 .

[2]  Z. Rengel,et al.  Arsenic speciation in terrestrial plant material using microwave-assisted extraction, ion chromatography and inductively coupled plasma mass spectrometry , 2003 .

[3]  W. Wenzel,et al.  Arsenic transformations in the soil-rhizosphere-plant system: fundamentals and potential application to phytoremediation. , 2002, Journal of biotechnology.

[4]  A. Violante,et al.  Competitive Sorption of Arsenate and Phosphate on Different Clay Minerals and Soils , 2002 .

[5]  Sally Smith.  Too much too young? In Nepal more a case of too little, too young. , 2002, International journal of epidemiology.

[6]  G. Stingeder,et al.  Arsenic in field-collected soil solutions and extracts of contaminated soils and its implication to soil standards , 2002 .

[7]  R. Naidu,et al.  Chemistry of inorganic arsenic in soils: II. Effect of phosphorus, sodium, and calcium on arsenic sorption. , 2002, Journal of environmental quality.

[8]  K. Linge,et al.  Interference from arsenate when determining phosphate by the malachite green spectrophotometric method , 2001 .

[9]  S. Tokunaga,et al.  Extraction of arsenic in a synthetic arsenic-contaminated soil using phosphate. , 2001, Chemosphere.

[10]  P. Hinsinger.  Bioavailability of soil inorganic P in the rhizosphere as affected by root-induced chemical changes: a review , 2001, Plant and Soil.

[11]  Z. Rengel,et al.  COMPILATION OF SIMPLE SPECTROPHOTOMETRIC TECHNIQUES FOR THE DETERMINATION OF ELEMENTS IN NUTRIENT SOLUTIONS , 2001 .

[12]  J. Dunlop,et al.  Phosphate absorption by Arabidopsis thaliana: interactions between phosphorus status and inhibition by arsenate. , 2000 .

[13]  P. Hinsinger,et al.  Dynamics of phosphorus in the rhizosphere of maize and rape grown on synthetic, phosphated calcite and goethite , 1999, Plant and Soil.

[14]  R. Pongratz.  Arsenic speciation in environmental samples of contaminated soil , 1998 .

[15]  David L. Jones.  Organic acids in the rhizosphere – a critical review , 1998, Plant and Soil.

[16]  F. Peryea.  Phosphate Starter Fertilizer Temporarily Enhances Soil Arsenic Uptake by Apple Trees Grown under Field Conditions , 1998 .

[17]  R. H. Loeppert,et al.  Arsenite and Arsenate Adsorption on Ferrihydrite: Kinetics, Equilibrium, and Adsorption Envelopes , 1998 .

[18]  F. Zhang,et al.  Phosphorus deficiency enhances root exudation of low-molecular weight organic acids and utilization of sparingly soluble inorganic phosphates by radish (Raghanus satiuvs L.) and rape (Brassica napus L.) plants , 1997, Plant and Soil.

[19]  M. Cox,et al.  Differential tolerance of canola to arsenic when grown hydroponically or in soil , 1996 .

[20]  R. Mclaren,et al.  Kinetics of cadmium and cobalt desorption from iron and manganese oxides , 1995 .

[21]  F. J. Peryea,et al.  Phosphate fertilizer enhances arsenic uptake by apricot liners grown in lead-arsenate-enriched soil , 1994 .

[22]  P. Hinsinger,et al.  Release of non exchangeable potassium from different size fractions of two highly K-fertilized soils in the rhizosphere of rape (Brassica napus cv Drakkar) , 1993 .

[23]  W. H. Patrick,et al.  Soil redox-pH stability of arsenic species and its influence on arsenic uptake by rice , 1993, Plant and Soil.

[24]  E. Hoffland.  Quantitative evaluation of the role of organic acid exudation in the mobilization of rock phosphate by rape , 1992, Plant and Soil.

[25]  A. Meharg,et al.  The mechanisms of arsenate tolerance in Deschampsia cespitosa (L.) Beauv. and Agrostis capillaris L.: Adaptation of the arsenate uptake system. , 1991, The New phytologist.

[26]  F. J. Peryea,et al.  Phosphate-Induced Release of Arsenic from Soils Contaminated with Lead Arsenate , 1991 .

[27]  R. Delaune,et al.  Effect of redox potential and pH on arsenic speciation and solubility in a contaminated soil , 1991 .

[28]  J. Davenport,et al.  Phosphate fertilizers influence leaching of lead and arsenic in a soil contaminated with lead arsenate , 1991 .

[29]  M. Böttger,et al.  Contribution of organic acids to the acidification of the rhizosphere of maize seedlings , 1991, Plant and Soil.

[30]  U. Schwertmann,et al.  Iron Oxides in the Laboratory: Preparation and Characterization , 1991 .

[31]  A. Meharg,et al.  An altered phosphate uptake system in arsenate‐tolerant Holcus lanatus L. , 1990 .

[32]  G. Sposito,et al.  Phosphorus adsorption by kaolinite and montmorillonite: I. Effect of time, ionic strength, and pH , 1988 .

[33]  R. Merry,et al.  The effects of contamination of soil with copper, lead and arsenic on the growth and composition of plants , 1986, Plant and Soil.

[34]  P. C. Kearney,et al.  THE CHEMISTRY AND PHYTOTOXICITY OF ARSENIC IN SOILS. II. EFFCETS OF TIME AND PHOSPHORUS , 1973 .

[35]  J. Quirk,et al.  THE MECHANISM OF PHOSPHATE ADSORPTION BY KAOLINITE, GIBBSITE, AND PSEUDOBOEHMITE , 1966 .

[36]  E. Hoffland,et al.  Solubilization of rock phosphate by rape , 2005, Plant and Soil.

[37]  Donald L. Sparks,et al.  Residence time effects on arsenate adsorption/desorption mechanisms on goethite , 2001 .

[38]  Jb Robinson,et al.  Plant Analysis: An Interpretation Manual , 1997 .

[39]  F. J. Peryea,et al.  Phosphate-enhanced movement of arsenic out of lead arsenate-contaminated topsoil and through uncontaminated subsoil , 1997 .

[40]  D. Parker,et al.  Accumulation and Interactions of Arsenic, Selenium, Molybdenum and Phosphorus in Alfalfa , 1991 .

[41]  A. Novacky,et al.  Evaluation of arsenate- and vanadate-associated changes of electrical membrane potential and phosphate transport in Lemna gibba G1 , 1989 .

[42]  C. Asher,et al.  Arsenic Uptake by Barley Seedlings , 1979 .

[43]  J. Quirk,et al.  Competitive adsorption of negatively charged ligands on oxide surfaces , 1971 .

[44]  L. W. Jacobs,et al.  Arsenic ‐ phosphorus interactions on corn , 1970 .