Co-contamination of deltamethrin and cadmium induce oxidative stress in tomato plants (Solanum lycopersicum L.)

Pyrethroids (deltamethrin) are increasingly being used in modern agriculture. In addition, cadmium (Cd) has considerable use in a wide spectrum of industrial fields. Consequently, combined pollution with deltamethrin (DM) and Cd is a common phenomenon in soil. In this study, the toxic effects of DM and Cd were investigated alone and in combination. Plant tomatoes (Solanum lycopersicum L.) were treated with deltamethrin (25 µM) or Cd (100 µM) or with DM–Cd co-contamination for 7 days. Both DM and Cd were significantly affected growth rate and reduced the levels of photosynthetic pigments though Cd seemed to be more deleterious than DM. Furthermore, DM and Cd induced hydrogen peroxide accumulation, lipid peroxidation, upregulated of anti-oxidative enzyme activities (APX, CAT, POD and PAL) and non-enzymatic such as proline, and reduced glutathione. These results revealed that oxidative stress is involved in the toxicity of DM and Cd, and proved that under a co-exposing condition, DM and Cd had a synergistic effect on the growth and content of photosynthetic pigments and an antagonistic interaction on antioxidant defense. Further studies on mixture toxicities are needed to explore the detailed mechanism of synergetic interaction to improve the environmental risk assessment of chemicals by applying the OMIC approaches.