Multidimensional role of selenium nanoparticles to promote growth and resilience dynamics of Phaseolus vulgaris against sodium fluoride stress.

High fluoride (F) concentrations negatively affect the seed germination, plant growth, development, and yield of crops. Phaseolus vulgaris L. is an F-sensitive crop frequently grown on marginal lands affected by F salts. Selenium (Se) is a vital elicitor of the antioxidative enzymes involved in scavenging free radicals to alleviate abiotic stress. Recent studies have demonstrated that engineered nanoparticles (NPs) have the potential to induce tolerance to abiotic stress in plants. Phytosynthesis of NPs is a novel and sustainable approach to mitigate abiotic stresses. The present study was intended to assess the role of green synthesized Se-nanoparticles (Se-NPs) in improving the physiochemical attributes, growth, and F stress tolerance of P. vulgaris growing in 200 ppm sodium fluoride (NaF) stress. NaF toxicity reduced Chl a, Chl b, and carotenoid content by 88.8%, 95.5%, and 96% compared to control with maximum improvement obtained through phyto-nano seed priming and foliar spray of 70 ppm Se-NPs. The joint treatment of NPs application through seed priming and foliar spray improved stomatal conductance (14.2%) and transpiration rate (11.7%) in plants subjected to NaF stress. The protein content (91.02%) and DPPH activity (33.72%) decreased under NaF stress, which was improved by phyto-nano seed priming and foliar spray (14.10%). Furthermore, the integrated application of Se-NPs seed priming and foliar spray increased nutritional content (P, K, Ca, Mg, and Zn), proline, ascorbic acid, and phenol yet reduced the level of NaF in plants. Se-NPs at 70 ppm were found to be more effective than 60 ppm in all modes of applications. Our results reveal a perception that Se-NPs increase P. vulgaris growth in NaF stress conditions, perhaps through a multipronged approach: improving photosynthetic content, nutrient uptake, and yield of P. vulgaris. Consequently, the findings of this study may be used for breeding and screening F-tolerant cultivars.