ABSTRACT
High salt concentrations and high pH occur simultaneously in nature, however, presently most of the studies have mainly focused on only salinity, the research on salt-alkali combined stress are comparatively very limited. Hydrogen peroxide is an important signaling molecule. However, the role of exogenously applied hydrogen peroxide (H2O2) under saline–alkaline stress is not known. The main objectives of present study was to assess role of exogenously applied H2O2 as seed priming in mitigating the harmful effect of saline–alkaline stress on differentially tolerant mungbean genotypes (TMB-37 and MH-1314). Saline-alkaline stress significantly decreased the chlorophyll content, leaf relative water content (RWC) and yield while enhanced malondialdehyde (MDA), proline and antioxidant enzyme activity in root and leaf samples of both mungbean cultivars. Seeds priming were done with 0.01% H2O2 and distilled water. Seed priming with 0.01% H2O2 significantly improved the yield and yield attributes along with increment in leaf chlorophyll content, RWC as well as accumulation of osmolytes. The activities of antioxidant enzymes, viz., SOD, CAT and POX were also significantly increased in both mungbean genotypes and especially the CAT activity both in root and leaf tissue. However, relatively higher improvement was observed in genotype TMB-37. In conclusion, exogenously applied 0.01% H2O2 improved the saline–alkaline tolerance, which was reflected in terms of enhanced photosynthetic pigments, RWC, proline accumulation, and antioxidant enzyme activity of root as well shoot tissues and yield.