Mitigation of Water Deficit Stress by Exogenous Application of Salicylic Acid in Rice

Abstract

Water deficit is a major environmental stressor that negatively affects plant growth and yield. This study investigated the role of salicylic acid (SA) to mitigate the adverse effects of extended irrigation intervals (12 days between two consecutive irrigations) in rice (Oryza sativa L.), specifically the Giza 183 variety, under Egyptian conditions. Foliar application of SA at 0.5 and 1 mM alleviated the adverse effects of extended irrigation intervals, improving growth and yield attributes. SA treatments enhanced plant height, leaf area, dry weight, and the tillers number under both normal and extended irrigation intervals during the 2023 and 2024 growing seasons. Additionally, SA application increased chlorophyll content (Chl a, Chl b, and total Chl), proline levels, relative water content, and total leaf phenols. The treatments also reduced sterility percentage and improved yield-related parameters, i.e. panicle length and weight, grain yield, and 100 grain weight. Among the treatments, foliar of SA at 0.5 mM consistently achieved the highest values across most traits in both seasons. These findings highlight the beneficial effects of SA, particularly at 0.5 mM, in mitigating the detrimental impacts of extended irrigation intervals on rice plants variety Giza 183 under Egyptian conditions.