Differential response of Oryza sativa L. and Phragmites australis L. plants in trace elements contaminated soils under flooded and unflooded conditions.

Abstract

Drastic changes in the water regime of trace elements (TEs) contaminated soils under semiarid conditions, from completely dry to flooding situations, may alter the solubility of the contaminants and, therefore, their potential mobility and availability to plants. Certain macrophyte species have shown a promising suitability for their use in the phytoremediation of TEs contaminated soils under fluctuating flooded-unflooded conditions, as a consequence of their high resistance and tolerance to contamination. Similarly, different water conditions occur during rice (Oryza sativa) cultivation, a species often used as a model plant for TEs toxicity studies. The aim of this work was to study the tolerance and oxidative response to TEs of common reed (Phragmites australis) and rice grown in contaminated mining soils, when exposed to different water saturation conditions. Both species (common reed and rice) were cultivated in three different contaminated soils from the Sierra Minera of La Unión-Cartagena (SE-Spain) under contrasting water saturation conditions (flooded and unflooded) in a pot experiment. Soil EC and elevated metal (mainly Cd and Zn) soluble concentrations conditioned the survival of the plants. Whereas, As accumulation in the aerial part of both species influenced the most oxidative stress homeostasis. Common reed showed to be a good candidate for its use in the phytostabilization of TEs contaminated soils under both flooded and unflooded conditions.