Using Plasma-Activated Water Generated by an Air Gliding Arc as a Nitrogen Source for Rice Seed Germination

This research aimed to understand the use of air gliding arc (GA) plasma to generate plasma-activated water (PAW) for fixing nitrogen in water and the chemical properties of PAW on the germination of rice seeds. The N2, NO, and OH molecules in GA plasma led to NO3-, NO2-, and H2O2 formation in the PAW. The NO3-, NO2-, and H2O2 contents in PAW rapidly decreased after 5 days of storage. The experiment was arranged in a completely randomised design using GA plasma discharged above the surface of deionised (DI) water with different airflow rates (2, 3, 4, 5, and 6 L/min) compared to the control (DI water). The NO3- and NO2- contents increased, resulting in an increase in total nitrogen (N) and gibberellic acid (GA3) accumulation in rice seeds. The PAW at an airflow rate of 5 L/min was optimal for enhancing radicle emergence at 48 and 72 h, germination, germination index, shoot length, fresh weight, and dry weight of seedlings. Therefore, air GA plasma to generate PAW is an efficient method for producing nitrogen in a soluble form, which can support the germination processes and early growth of rice seedlings.