Influence of radiation on green-synthesized AgNPs and their role in enhancing fluoride stress tolerance in rice

Fluoride stress severely impairs the growth and productivity of economically important crops, including rice, resulting in significant yield losses and threatening agricultural sustainability. Enhancing crop resilience requires strategies that balance plant development and stress responses. In this study, we adopted a multi-step approach to mitigate fluoride toxicity in rice. First, soil properties—texture, organic matter, pH, and nutrient content—were analysed to guide crop recommendations and optimize yield. Second, silver nanoparticles (AgNPs) were synthesized using a green approach with Bryophyllum pinnatum plant extract and characterized by UV–Vis spectroscopy, FTIR, SEM, XRD and DLS, confirming their structural integrity and morphological changes. Third, the interaction of radiation with B. pinnatum plant extract and AgNPs was examined, revealing higher energy absorption in the extract compared to nanoparticles. Finally, plant responses under fluoride stress were evaluated by comparing AgNP priming with conventional foliar fertilizer. AgNP treatment significantly improved germination, root and shoot length, photosynthetic pigments (chlorophyll), and antioxidant enzyme activity, resulting in enhanced growth and yield. These findings demonstrate, for the first time, that AgNP priming effectively regulates fluoride-sensitive defense pathways, offering a promising strategy for developing fluoride-tolerant crops and improving agricultural productivity under stress conditions.