Plasma-activated water processing and storage time impacts pea microgreens yield and quality

Plasma-activated water (PAW) is emerging as a sustainable input capable of enhancing crop yield and quality while reducing dependence on synthetic fertilizers. However, how PAW chemistry evolves during storage and how these dynamics translate into crop growth and quality remain poorly understood. This study evaluated the effects of plasma activation time (30, 60, 90, and 120 min) and application timing (immediately after generation versus after 72-h storage) on the physicochemical properties of PAW and yield, mineral composition, and phytochemical profile of pea (Pisum sativum L.) microgreens.

PAW generated with an air gliding-arc discharge exhibited characteristic shifts in reactive species: freshly generated PAW contained higher reactive oxygen and nitrogen species (RONS) and lower pH; however, storage promoted nitrate accumulation and the decay of short-lived oxidants. These chemical transitions strongly influenced plant responses. When applied immediately, moderate activation (30-90 min) increased fresh yield and dry biomass by 5-13%, whereas PAW activated for 120 min reduced yield while increasing water use efficiency (WUE), likely reflecting reduced water uptake rather than improved plant growth efficiency. In contrast, all 72-h stored PAW treatments improved yield relative to tap water, with PAW activated for 60 min producing the highest biomass (+19.7%) and the greatest improvement in WUE (+21.5%). Stored PAW also enhanced calcium and magnesium accumulation and increased carotenoids, phenolics, and flavonoids.

These results demonstrate that PAW functionality is strongly determined by the balance between reactive oxygen species (ROS)-driven stress and reactive nitrogen species (RNS)-derived nutrition, both of which depend on activation and storage time. Optimizing these parameters can simultaneously improve productivity, resource-use efficiency, and nutritional quality in microgreen production systems. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.