Germination, Physicochemical Properties, and Antioxidant Enzyme Activities in Kangkong (Ipomoea aquatica Forssk.) Seeds as Affected by Dielectric Barrier Discharge Plasma

Abstract

Dielectric barrier discharge (DBD) plasma has been utilized as a sustainable technology to enhance seed germination in various plant species. The objective of this research was to identify the mechanism of physicochemical properties and antioxidant enzyme activities to promote kangkong (Ipomoea aquatica Forssk.) seed germination using different durations of DBD plasma treatments. Seeds were exposed to atmospheric DBD plasma from 5 to 20 min, compared to non-treated seeds as the control. According to SEM images, the seed surface had cracks and grew wider as a result of the prolonged DBD plasma treatments. A longer DBD plasma treatment exhibited a lower water contact angle and increased water absorption. DBD plasma treatments strongly improved germination percentages and hydrogen peroxide (H2O2) contents. Seeds treated with DBD plasma for 20 min showed the highest malondialdehyde (MDA) content and the lowest field emergence. Catalase (CAT) activity increased under DBD plasma treatments for 5 and 10 min. Ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities were not statistically different among the treatments. This finding suggested that DBD plasma treatments stimulated the germination of kangkong seeds by modifying the seed surface, and upregulating H2O2 content and CAT activity. Five minutes was an appropriate time to treat DBD plasma.