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Evaluation of an electrostatic toxicity model for predicting Ni 2+ toxicity to barley root elongation in hydroponic cultures and in soils
Author(s) -
Wang Peng,
Kopittke Peter M.,
De Schamphelaere Karel A. C.,
Zhao FangJie,
Zhou DongMei,
Lock Koen,
Ma YiBing,
Peijnenburg Willie J. G. M.,
McGrath Steve P.
Publication year - 2011
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2011.03806.x
Subject(s) - toxicity , elongation , soil water , phytotoxicity , botany , chemistry , biology , agronomy , ecology , materials science , metallurgy , organic chemistry , ultimate tensile strength
Summary• Assessing environmental risks of metal contamination in soils is a complex task because the biologically effective concentrations of metals in soils vary widely with soil properties. • The factors influencing the toxic effect of nickel (Ni) on root growth of barley ( Hordeum vulgare ) were re‐evaluated using published data from both soil and hydroponic cultures. The electrical potential ( ψ 0 o ) and ion activities ({ I z } 0 o ) at the outer surfaces of root‐cell plasma membranes (PMs) were computed as the basis of the re‐evaluation. • The reanalyses demonstrated that root growth was related to: the Ni 2+ activity at the PM surface, ({Ni 2+ } 0 o ); calcium (Ca) deficiency (related to {Ca 2+ } 0 o ); osmotic effects; and modification of intrinsic Ni 2+ toxicity by magnesium (Mg 2+ ; this appeared to exert an intrinsic (specific) ameliorating effect on intrinsic Ni 2+ toxicity). Electrostatic toxicity models (ETM) were developed to relate root growth to these factors ( R 2 > 0.751). • Based on the ETM developed in soil culture and a Ni 2+ solid–solution partitioning model, critical metal concentrations in soils linked to a biological effect were well predicted for 16 European soils with a wide range of properties, indicating the potential utility of ETM in risk assessment of metals in terrestrial ecosystems.