Phytoremediation Potential of Copper Contaminated Soils in <i>Calendula officinalis</i> and Effect of Salicylic Acid on the Growth and Copper Toxicity

Abstract

The present research was carried out to assess the effectiveness Calendula officinalis on removing the Cu from the contaminated soil and to examine the effects of salicylic acid (SA) on growth and some eco-physiological, biochemical characteristics in plants exposed to copper stress. This experiment was arranged as a factorial experiment based on completely randomized design with four replications in greenhouse conditions. The experimental treatment consisted of four levels of Cu (0, 100, 200, and 400 mg/kg in potted soil) and three levels of salicylic acid (0, 1, 2mM) as foliar spray and chelate into soil. Results showed that with increasing levels of copper, reductions in shoot and root growth, leaf area and leaves number were statistically significant at 1 percent level. Although the copper concentration in shoots of Calendula officinalis could not exceed 1,000 mg/kg dry weight, the results showed that copper accumulation was higher in the shoots than in the roots. The results of the concentration of copper showed that translocation (TF) and bio-concentration factor (BCF) was greater than 1. Thus, Calendula officinalis could be classified as a copper tolerant species. Application of SA was found to alleviate negative effects generated by heavy metals like copper in plants. SA significantly increased growth and resistance index in copper stressed plants. SA as chelate in concentration of 2mM had the greatest effect on studied parameters. Results showed that salicylic acid can increase the efficiency of phytoremediation successfully.