Atmospheric Corona Discharge Plasma for Rice (Oryza sativa L.) Seed Surface Modification, Fungi Decontamination, and Shelf Life Extension

Abstract

We demonstrate atmospheric corona plasma can modify rice (Oryza sativa L.) seed surface wettability and eliminate attached microorganisms at ambient temperatures, which can enhance germination and extend shelf life. High electric field strength up to 10 5 V/cm at the electrode tips is the critical factor for generating corona discharge plasma and, consequently, providing reactive oxygen and nitrogen species (RONS) via electron-induced impact ionization. We show that the reactive species and ions are primarily responsible for enhanced seed surface wettability via water imbibition (WI) and apparent contact angle (ACA) measurement. A scanning electron microscope was employed to confirm that the cold corona plasma treatment can decontaminate seedborne pathogenic fungi. Sterilized seeds with better surface wettability are more likely to germinate and yield higher quality seedlings. In addition, we demonstrate the potential use of the corona plasma process for seed storage extension and quality retention through accelerated aging germination and decreased moisture content. Germination of treated seed after passing accelerated aging process is approximately 90%, similar to that of unaged and untreated seeds.

Nonthermal Plasma Effects on Fungi: Applications, Fungal Responses, and Future Perspectives

“…Corona discharges can be operated in direct current or pulsed mode, where the pointed electrode has a negative or positive potential [ 9 ]. Corona discharges are used in various industrial applications [ 16 , 17 , 18 , 19 , 20 , 21 ].…”