Plasma Seed Priming Can Improve the Early Seedling Establishment and Antioxidant Activity of Water Convolvulus Microgreens

Water convolvulus (<i>Ipomoea aquatica</i> Forssk.) is a fast-growing leafy vegetable valued for its nutritional and antioxidant properties; however, suboptimal seed physiology can hinder its germination and early growth. Non-thermal plasma (NTP) treatment is an eco-friendly seed-priming method that enhances seed performance and crop quality without the use of chemical inputs. This study evaluated the effects of NTP exposure (0, 5, 10, and 20 min) using a dielectric barrier discharge (DBD) plasma with an air gas flow rate of 1.5 lpm on the germination, seedling growth, pigment and protein content, nitrogen assimilation, and antioxidant capacity of water convolvulus. Plasma treatment of seeds increased germination in a time-dependent manner. The surface hydrophilicity improved with increasing treatment time. Seedlings grown from seeds treated for 10 min exhibited longer shoots (+10.1%) and roots (+17.8%). The shoot nitrate content increased by 66.3%. At 10 min, the total phenolics and flavonoids increased by 26.5% and 37.2%, respectively, with an accompanying increase in antioxidant activity, as measured by DPPH, ABTS, and FRAP assays. These findings demonstrate that a 10 min NTP treatment of seeds improves germination, growth, nutrient assimilation, phytochemical accumulation, and antioxidant activity in water convolvulus seedlings, highlighting its potential as a sustainable and chemical-free seed-priming technology with considerable potential to enhance the productivity and nutritional quality of plant microgreens in modern agriculture.