Germination, Growth, and Secondary Metabolite Contents of Radish Sprouts (Raphanus sativus L.) as Affected by Plasma Activated Water Process Time

This study was performed to investigate the effects of plasma-activated water on germination, growth, and functional properties of radish sprouts. The experimental design involved radish seeds cultivated in different concentrations of plasma-activated water for seven days, with plasma water generated by 10, 20, or 30 minutes of plasma discharge in water. The underwater plasma discharge produced nitrate ions and hydrogen peroxide(H2O2) and changed the pH and electrical conductivity. The plasma-activated water improved germination, and the longer the underwater plasma generation time, the better the effect. In terms of growth, plasma-activated water treatment oxidized the roots and negatively affected plants. Functional substance analysis showed that the levels of indolic and aliphatic glucosinolates increased, with 30 min of plasma treatment leading to the highest results. Similarly, the phenolic content increased with increasing plasma discharge time, with the 30 min treatment increasing phenolic content by 288.8% compared to the control. The results of this study suggest that plasma-activated water can increase the functional components of plants during hydroponic cultivation. However, more research is required to solve these growth disorders observed with plasma-activated water use.