Salicylic acid induced amelioration in growth, biochemical metabolites and yield of mungbean (Vigna radiata L.) under salinity stress

The study was conducted in green house to determine whether exogenous application of salicylic acid (SA) through foliar spray could modulate the plant growth, biochemical attributes, mineral nutrition and yield in mungbean (Vigna radiata L.) under two levels of salinity. The chloride dominated (Cl: SO₄ ratio 7:3) salinity was maintained in earthen pots at 4 and 6 dS m⁻¹ levels after seed germination. At flower initiation, two concentration of salicylic acid viz 0.25 and 0.50 mM were applied as foliar spray on both control and salinity treated plants and observations were recorded at 2 and 6 days after spray of salicylic acid. Increasing salt stress reduced the dry matter accumulation in leaves, stem and roots alongwith leaf area. The salicylic acid application at 0.5 mM improved the growth parameters and the response was more at 6 days stage. Biochemical metabolites i.e. total soluble protein declined under salinity stress, however, free proline, total soluble carbohydrates, and free amino acids content showed sharp rise under salinity stress. Foliar SA application increased all the above biochemical metabolites under salinity. The leaf ionic composition of Na⁺, Cl⁻and SO₄ increased but that of K⁺ declined under salinity stress. Salicylic acid reversed the accumulation trend of ions under salt stressed condition. Significant reduction in seed yield and its attributes were recorded under both levels of salinity. Salicylic acid application protected against salinity induced decline in yield components. The recovery was more pronounced at 6 dS m⁻¹ salinity as compared to 4 dS m⁻¹ salinity level particularly with 0.5 mM salicylic acid.