Synergistic effects of methyl jasmonate and salicylic acid enhances photosynthetic efficiency in drought-stressed French beans

Abstract

French bean, a vital member of the Fabaceae family, enjoys global popularity as both a vegetable and a pulse. However, its cultivation is increasingly challenged by drought, a consequence of dwindling water resources, climate change, and global warming. Applying phytohormones during early growth stages offers a promising strategy to mitigate drought stress. This study explored the individual and combined effects of methyl jasmonate (MJ) and salicylic acid (SA) on French bean plants subjected to drought conditions. The results demonstrated that drought significantly impaired various physiological and biochemical traits, including stomatal characteristics, photosynthetic performance, mesophyll pigment content, chlorophyll fluorescence, and biomass accumulation. Drought increased stomatal density but decreased stomatal size, leading to reduced gas exchange and photosynthetic rates. While MJ or SA alone partially alleviated the adverse effects of drought on the studied traits, their combined application proved significantly more effective. The combined treatment improved stomatal attributes, photosynthetic efficiency, and biomass production. Additionally, it enhanced leaf water content, reduced membrane permeability, and regulated proline and soluble sugar levels, contributing to improved plant resilience under drought conditions. A correlation analysis revealed strong correlations between biomass production and key physiological traits, further underscoring the synergistic potential of MJ and SA in enhancing drought tolerance in French beans. The findings of this study could contribute to the development of more effective management strategies for French bean cultivation in water-limited environments.