Foliar Application of Selenium Nanoparticles on Celery Stimulates Several Nutrient Component Levels by Regulating the α-Linolenic Acid Pathway

Selenium nanoparticles (SeNPs) show potential tendency in improving the plant health and food quality. However, the mechanism underlying SeNPs’ capability to enhance the biosynthesis of more nutrient components such as flavonoids in crops remains unclear. In this study, it is found that foliar application of SeNPs on celery significantly enhanced the total antioxidant capacity, total flavonoids, total phenols, and vitamin C levels of celery leaves by 46.7, 50.0, 21.4, and 26.7%, respectively. The SeNP application enhanced the biosynthesis of flavonoids, such as apigenin (58.4%), rutin (66.2%), p-coumaric acid (80.4%), ferulic acid (68.2%), luteolin (87.0%), and kaempferol (105.7%). The levels of nutrients such as arginine, tryptophan, and β-carotenes also increased by 147.8, 91.5, and 61.4%, respectively. For other components, the α-linolenic acid (73.8%), 13(S)-hydroxy linolenic acid (65.0%), 12-oxophytodienoic acid (197.5%), and jasmonic acid (72.9%) levels increased in SeNP-treated celery leaves. In conclusion, it was proposed that the mechanism of SeNPs for stimulating nutrient component levels might enhance the antioxidant capacity by regulating the α-linolenic acid pathway, leading to greater biotransformations or accumulation of various nutrients in celery.