Effect of Salinity and Cadmium on Chlorophyll Content, Antioxidant Activity and Weight of Kochia Plant (Kochia indica)

In order to investigate the effect of salinity and cadmium (Cd) on yield, chlorophyll content and antioxidant activity of Kochia plant, a factorial experiment in a completely randomized design with three replications was conducted under greenhouse conditions. The experimental treatments included five Cd levels (0, 5, 30, 60 and 90 mg Cd kg-1 soil as cadmium sulphate) and three salinity levels (0, 2.5 and 5 g kg-1 soil as NaCl equal to electrical conductivity (EC) 0.65, 9.4, and 18 dS m-1, respectively). The results showed that mean shoot fresh and dry weight, root weight, and plant height at 5 g NaCl Kg-1, decreased significantly by 22, 24, 23, and 15 %; and at 90 mg Cd Kg-1 soil decreased by 52, 67, 45, and 41%, respectively. The greatest reduction in shoot fresh and dry weight, root dry weight and plant height observed at 5 g NaCl Kg-1 + 90 mg Cd Kg-1 levels. The highest total chlorophyll content observed at control (with no salinity and Cd) and 5 g kg-1 salinity + 5 mg Cd kg-1. With addition of NaCl, the harmful effect of Cd on chlorophyll content of the plant decreased. Salinity and Cd levels had a different effects on antioxidant activity of Koshia plant. However, at higher Cd levels (60 and 90 mg Cd kg-1), with increasing of salinity levels, no significant differences was observed in peroxidase and superoxide dismutase activity. In general, the change in the activity pattern of the plant antioxidant system, especially catalase and superoxide dismutase enzymes under high stress conditions showed that Kochia plant can withstand stress conditions via activating its antioxidant system.