Nowadays the environmental pollution caused by heavy metals is spreading all over the world, especially where the industry is developing rapidly, and soils are polluted very dramatically and hazardously at a high level. In this study, cocklebur-(Xanthium strumarium L.) plants were grown in nickel (Ni) contaminated soil (0, 50, 100, 200 and 400 mg Ni kg -1 ) under greenhouse conditions for 6 weeks to study the ability of Ni uptake and accumulation of the plants. The Ni treated plants were

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... d with the control (0 mg Ni kg -1 ) plant. As a result of that comparison, chlorophyll levels of old and young leaves, dry weights, reduced glutathione (GSH), macronutrient concentrations, such as nitrogen (N), phosphor (P), potassium (K), calcium (Ca) and magnesium (Mg)) and micronutrient concentrations, such as iron (Fe), zinc (Zn), and manganese (Mn) nutrient concentrations of the plants were decreased, whilst the concentrations of Ni and of copper (Cu) increased with increasing dose of Ni application. The results show that the studied plant (Xanthium strumarium L.) can be used for the cleaning up of Ni-contaminated soils and is suitable for phytoremediation.