Effect of chitosan on antioxidant enzyme activity, proline, and malondialdehyde content in Triticum aestivum L. and Zea maize L. under salt stress condition

Triticum aestivum L. and Zea maize L. are both sensitive to salinity stress which is a major problem faced by farmers today. In the present study, the effect of chitosan, a biologic elicitor under salinity stress was examined on growth parameters and biochemical markers in maize and wheat seedlings. Seeds of wheat and maize plants were coated with chitosan 25%, 50%, and 75% solutions before they were planted and subjected to 0, 50, 100, 150, and 200 mM salinity stress under a 11/8 h photoperiod and at 25±2 °C temperature condition during 7 days. Then, the growth parameters including germination percentage, root and shoot growth as well as seedling weight were recorded. The biochemical markers including catalase and peroxidase activity and malondialdehyde, proline, and protein contents were measured at day seven of the experiment. Significant difference in relation with growth parameters was observed at high concentrations of chitosan in comparison with the control plants under salt stress. Catalase and peroxidase activity and protein content increased under salinity stress and chitosan at high concentration reduced catalase and peroxidase activity. Salinity stress induced lipid peroxidation and malondialdehyde accumulation while chitosan reduced malondialdehyde content of the plants under salinity stress. The synthesis of protein was significantly increased with increasing the chitosan concentration. Generally, the growth parameters of both seedlings were improved and unfavorable effects of salinity were reduced when the seeds were coated with chitosan. Application of chitosan at low concentrations increased antioxidant enzyme activity and proline content and decreased MDA accumulation. In conclusion, chitosan at an appropriate dose improved growth performance and biochemical marker fluctuation under salinity stress.