Redox State in Solanum Seedlings under Cadmium Stress Conditions
Cadmium content and distribution as well as its effects on growth and oxidative stress were investigated in 17-day-old tomato seedlings (Solanum). The content of Cd increased with external Cd concentrations, and was considerably higher in roots than in shoots. Excess Cd suppressed biomass production of both roots and shoots and reduced chlorophyll content in leaves. Further, substantial increases of H2O2 and ascorbate contents, malondialdehyde formation, and antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (GPX) were observed in Cd-stressed plants in comparison with controls. The results suggest that the phytotoxic effects of Cd in tomato seedlings may be achieved by an enhanced production of active oxygen species (AOS) and subsequent lipid peroxidation with ascorbate synthesis as singe of tomato tolerance.