FOLIAR-APPLICATION OF PROLINE MITIGATES SALINITY STRESS IN MAIZE (ZEA MAIZE L.): A COMPARATIVE STUDY ON GROWTH, PHYSIOLOGY, AND ION COMPOSITION

Salinity is a significant constraint for crop production globally, alongside other stresses such as drought. Salinity reduces the growth and yield of maize. A wide range of literature covers that proline, when exogenously applied, helps plants to mitigate the unfavorable impacts of abiotic stresses. While the role of exogenously applied proline in enhancing plant defense has been studied, its specific effects on maize under salinity stress require further exploration. A hydroponic study was conducted using two maize genotypes Monsanto-6525 and Pioneer-33H25, exposing to four treatments including control, salinity (75 mM NaCl), proline (30 mM), and proline (30 mM) + salinity (75 mM NaCl). Foliar application of proline (control, 30 mM) was done at 15 mL per plant after 20 days of transplantation. Proline showed positive results by influencing growth (shoot and root dry weights), physiological (total chlorophyll contents, relative water contents, membrane stability index) responses, proline and ionic compositions i.e. shoot and root sodium (Na) and potassium (K). The Na was reduced, and K was improved in both maize genotypes by foliar-applied proline, however, this improvement was more perceived in Monsanto-6525 cultivar when compared with Pioneer-33H25. Overall, the study suggests that foliar application of proline can be an effective strategy for improving maize tolerance to salinity stress, with cultivar-specific responses indicating the potential for targeted application.