Effects of Heavy Metal-Polluted Soil (Pb, Zn, and Cd) on Seed Emergence, Seedling Growth, and Antioxidant Activity in Four Fabaceae Species

Mine tailings can contaminate large areas of neighboring agricultural lands due to the dispersion of heavy metals, which may lead to reduction in soil fertility and toxicity in crops. The use of Fabaceae species as green manure to amend the soil and enhance the removal of heavy metals is a promising research approach. As part of a phytoremediation project for abandoned mining sites combining woody species and agricultural crops, this study aims to identify the most suitable species to be used. Thus, four Fabaceae species (Vicia faba, Cicer arietinum, Lens culinaris, and Medicago arborea) were subjected to muti-metal-contaminated soil containing high concentrations of Pb, Zn, and Cd and to control soil for 15 days. Then, the emergence rate, growth parameters, lipid peroxidation, proline and hydrogen peroxide (H2O2) concentrations, antioxidant enzyme activities (catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GPX)), and heavy metals accumulation were evaluated. Results showed that V. faba was the most tolerant. A relative sensitivity at the germination stage was recorded for all species with the exception of V. faba. Metallic stress had no significant effect on thiobarbituric acid reactive susbtances (TBARS) and electrolyte leakage rates for both C. arietinum and V. faba. The latter also showed the highest proline concentration and relatively low antioxidant enzyme activities. All species showed high Pb, Zn, and Cd root contents. V. faba had the lowest translocation factors of Pb and Zn and the lowest bioaccumulation factors of Zn and Cd, which underline its phytostabilizing potential and support its use as green manure for heavy metals contaminated soils amendement and rehabilitation.