Evaluation of antioxidant and morphophysiological alterations in polyethylene glycol primed Raphanus sativus L. under sodium fluoride stress.

Among the abiotic stresses that adversely affect plants, sodium fluoride (NaF) interferes with physicochemical parameters, reducing growth, yield, and biomass accumulation in various plants, particularly radish (Raphanus sativus L.). Sodium fluoride negatively interacts with several pathways related to photosynthesis, protein synthesis, and antioxidant activity. This study was designed to discover the potential of polyethylene glycol (PEG) seed priming in alleviating NaF stress in R. sativus. During this study, seeds of R. sativus were divided into two groups: primed seeds and nonprimed seeds. Polyethylene glycol was used at four different concentrations (PEG-10%, PEG-20%, PEG-30%, and PEG-40%) for seed priming, and PEG-30% proved to be the most effective against the adverse effects of NaF. Compared with nonprimed plants, plants primed with PEG-30% showed increase in various growth parameters, including shoot length (51.13%), root length (46.06%), shoot fresh weight (58.18%), shoot dry weight (86.62%), root fresh weight (74.62%) and root dry weight (66.66%) under NaF stress. A similar trend was observed for photosynthetic pigments and total soluble proteins under stress. This is the first research showing the stress ameliorating and growth-improving role of PEG priming in R. sativus under NaF stress.