Organic amendments mitigate salinity induced toxic effects in maize by modulating antioxidant defense system, photosynthetic and ionic homeostasis

Salinity stress (SS) is a major and increasing abiotic stress adversely affecting plant growth and productivity across the globe. The application of organic amendments (OA) is considered to be an important practice to mitigate the adverse impacts of SS. Therefore, this study was performed to assess the impact of different OA on growth, physiology and anti-oxidant activities of maize plants grown under SS. The study was comprised of diverse SS levels; 0, 6 and 12 dS m', and different OA; control, cow manure (CM: 5%), sugarcane pressmud (SPM: 5%) and combination of CM (2.5%) + SPM (2.5%). The study was conducted in a completely randomized design with factorial arrangement having three replications. The results indicated that SS reduced the growth and biomass production, relative water contents (RWC), chlorophyll contents, free amino acids (FAA), total soluble proteins (TSP) and increased the electrolyte leakage (EL: 40.92%), hydrogen peroxide (H202: 68.49%), malondialdehyde (MDA: 42.13%), and catalase (CAT: 34.24%) and ascorbate peroxide (APX: 25.70%). The application of OA significantly improved the maize growth under SS. However, the application of SPM (5%) significantly increased growth and biomass production by decreasing EL, MDA and H2O2 accumulation and increasing RWC, chlorophyll, CAT, POD, and anthocyanin, TSP and FAA. These findings suggest that application of SPM improved the growth and biomass production of maize by improving anti-oxidant activities, photosynthetic pigments, TSP, FAA reducing lipid peroxidation and EL.