Journal of Bioscience and Biotechnology Discovery

Rice is the main staple food for one-third of people worldwide providing up to 80% of these individuals' daily calories. Drought is adverse, affecting crop plants' growth, yield, quality and nutritional value. Likewise, it causes social unrest and economic loss to the farmers and governments. The current study aimed to examine the impact of environmentally friendly silver nanoparticles (AgNPs) on the physiological, yield, and growth parameters of rice plants in response to drought. The most widely manufactured engineered nanomaterials at the moment, silver nanoparticles (AgNPs) are present in a large variety of commercial products. The aqueous leaf extract of Azadrachta indica was used to create the plant-based AgNPs. The leaves of Azadirachta indica were extracted aqueously to create the plant-based AgNPs. In order to determine the metabolites of drought stress, the AgNPs were characterised using X-ray diffraction (XRD), GC-MS, furrier transform infrared (FTIR), UV-visible spectrophotometry, and scanning electron microscopy (SEM). Brown colouration was observed during synthesis, and this was confirmed by UV-visible at an absorbance peak of 300 nm. An FTIR machine also confirmed the presence of amine, alcohol and carboxylic, alkene, nitrogenous molecule, and alkyl halide at five significant peaks, spherical and with a crystalline size of 32.8 nm. GC-MS was used to identify octadecanoid acid, a metabolite associated with drought stress. Rice plants treated with different doses of AgNP in field studies became more tolerant to drought stress. It was discovered that the AgNPs significantly affected physiological, growth, and yield parameters in addition to total biomass. It was discovered that AgNPs at a concentration of around 20 mg/L were efficient in inducing metabolic alterations that led to drought stress. Furthermore, roots treated with AgNPs under drought stress showed less root aerenchyma than roots treated with AgNPs under well-watered conditions, which showed a greater number of aerenchymas. Due to the surface plasmon vibration, excitation of bio-reduction, capping or stabilising agent, and neem leaves' presence of octadecanoic acid (ethyl ester), which is essential in reducing drought stress tolerance in plants, especially rice, neem leaves were suggested for the synthesis of silver nanoparticles.