A novel technique of nutrition for the growth of wheat by alkaline plasma-activated water (APAW)

Cold atmospheric plasma represents an emerging technology with promising applications in agriculture. Plasma-activated water (PAW), an environmentally friendly technology, typically exhibits acidic properties and has been widely reported to enhance plant germination and growth through the action of reactive species. However, the effects of plasma-activated water with alkaline characteristics remain completely unknown. This study investigated the effects of alkaline plasma-activated water (APAW), enriched with reactive species generated through plasma electrolysis, on soil pH optimization and the enhancement of wheat germination, growth, and spike birth. Germination was evaluated by soaking seeds in tap water (TW) and alkaline plasma-activated water (APAW). After 1 day of soaking, the average germination percentage, germination speed, and germination rate were significantly higher in samples treated with alkaline APAW compared to those TW. The average seed vigor index in the APAW group was higher than that in the TW group after 2 and 4 days of treatment. Compared to the hydrogen ion concentration, the influence percentage of hydrogen peroxide concentration and oxidation–reduction potential on root and shoot length was greater than that of nitrite and nitrate ion concentrations. Growth parameters, soil pH, and spike birth were evaluated across four samples: AC (seeds soaked and irrigated with tap water), AD (seeds soaked with tap water and irrigated with APAW), BE (seeds soaked with APAW and irrigated with tap water), and BF (seeds soaked and irrigated with APAW). Samples irrigated with APAW exhibited the highest growth rates and the greatest increase in soil pH. Notably, spike birth was observed exclusively in APAW-irrigated samples throughout the 100-day experimental period.