Effects of high metal concentrations on antioxidative system in Phragmites australis grown in mine and flotation tailings ponds

Abstract

Aims: Phragmites australis grows as a pioneer plant species in several mine and flotation tailings ponds distinguished by extremely high concentrations of metals. The main goals of this study were to estimate the effects of the specific concentrations and combinations of accumulated metals on the efficiency of antioxidative enzymes and plant oxidative status. This study is relevant to our understanding of the common reed exceptional capacity to endure extreme edaphic conditions. Methods: Metal concentrations were determined in the sediment, roots and leaves. Antioxidative enzymes activities, amounts of pigments and phenolics, total antioxidative capacity (TAC), lipid peroxidation level (LP) were analysed in plant organs. Results: Effects of accumulated metals depended on their concentrations and their stoichiometry. Antioxidative enzymes and TAC in roots were significantly reduced, resulting in consequent increase in LP. Pb concentration in leaves did not significantly change enzymes activities, whereas toxic level of Cu impeded activity of catalaze and ascorbate peroxidase. Conclusions: The results indicate that in the conditions of high root metal contamination the mechanisms involved in their immobilization and detoxification cannot completely restrain their toxicity. Their effects on enzymes activities depend on the type of enzyme, metal concentrations, specific ratios and interactions.