Indole-acyl esters improve the effect of nitrogen and phosphorous fertilization by mitigating the phytotoxicity and concentrations of cadmium and lead in Jatropha curcas L. in contaminated soils

The effects of indole-acyl esters (ID), NH4NO3 (N), and KH2PO4 (P), on the mitigation of the toxic effects of Cd and Pb and their concentration in Jatropha curcas L. from contaminated soils was investigated. The concentrations of ID, N, and P were optimized (0.1 mL?L-1, 7 mM, and 2.5 mM, respectively) and they were applied in various combinations to the contaminated soils of potted plants of J. curcas. The results showed that ID together with the N and P fertilizers, increased plant biomass and improved the mitigating effects of the N-P treatments on Cd and Pb toxicity. Plants growing under ID-N-IP treatments had high whole plant biomasses, high concentrations of P, N, Pb and Cd in whole plants, as well as enhanced activities of superoxide dismutase (SOD) and peroxidase (POD). These results point to the phytoremediation ability of J. curcas. We propose a new methodology that can be utilized to study the effects and interactions of multiple factors on plant growth.