Comparative study of Zn-phytoextraction potential in guar (Cyamopsis tetragonoloba L.) and sesame (Sesamum indicum L.): tolerance and accumulation

Abstract

Phytoextraction is a plant-based technique for removing heavy metals from polluted soil. The experiment reported in this paper was undertaken to study the Zn phytoextraction potential of Cyamopsis tetragonoloba in comparison with Sesamum indicum in the framework of a pot experiment. Plants were subjected to six Zn concentrations (0, 50, 100, 200, 300, 400 mg kg−1 soil) for 90 days to investigate Zn tolerance and accumulation. Results demonstrated that, at higher Zn levels, root, shoot lengths, biomass and chlorophyll content were all significantly reduced (p < 0.05). A steady increase in Zn accumulation with increasing concentration in soil was observed for all treatments. Both plant species had relatively high Zn tolerance and accumulation capacity, with C. tetragonoloba being more tolerant and having higher Zn accumulation than S. indicum. At 400 mg Zn kg kg−1, accumulation of Zn in C. tetragonoloba was highest in the root (439.33 mg kg−1) followed by stem (436.00 mg kg−1), leaf (40.67 mg kg−1) and pod (11.33 mg kg−1). Considering the rapid growth, high biomass, tolerance, accumulation efficiency, bioconcentration factor (BCF), bioaccumulation coefficient (BAC) and translocation factor (TF) (all greater than 1) established C. tetragonoloba as a potential candidate plant for Zn phytoextraction.