Antioxidant and growth responses to nickel-induced stress and its amelioration studies using [S, S] ethylenediamine-N–N’-disuccinic acid in Solanum lycopersicum

The present study pertains to the evaluation of the effects of nickel on bioaccumulation, growth parameters, contents of protein, and antioxidant enzymes in root and shoots of Solanum lycopersicum as well as ameliorating effects of [S, S]-ethylenediamine-N–N’-disuccinic acid (EDDS). Nickel treatment at different concentrations (5, 10, 15, 20, 25, 30, 40, 50, 60, 100, and 250 µM) enhanced activities of all antioxidative enzymes in roots and shoots of S. lycopersicum when compared to the control. Dose-dependent increase was observed for dehydroascorbate (DHAR) and peroxidase (POD) up to 40 µM Ni while an increase was observed for ascorbate peroxidase (APX), catalase (CAT), and glutathione S-transferase (GST) up to 50 µM Ni. Activity of glutathione reductase (GR) was maximum at 5 µM Ni for roots and at 50 µM Ni for shoots. In the presence of EDDS, both roots and shoots have shown increased activity of POD at 40, 50, and 60 µM of Ni, and CAT at 60 µM of Ni whereas reduced activity of APX was shown at 40, 50, and 60 µM of Ni for shoots and at 40 and 50 µM of Ni for roots. GR exhibited increased activity in roots while reduced activity in shoots except at 60 µM of nickel treatment. No change was observed for translocation factor, protein, DHAR, and GST activities while bioaccumulation factor was enhanced at 50 and 60 µM of Ni in the presence of EDDS. Further, this present study clearly revealed that EDDS could combat nickel-induced stress in S. lycopersicum by enhancing activities of CAT, GR, and POD, resulting into ameliorated growth parameters.