Rice (Oryza sativa L.) Seed Sterilization and Germination Enhancement via Atmospheric Hybrid Nonthermal Discharge Plasma

Abstract

We designed a system to produce atmospheric hybrid cold-discharge plasma (HCP) based on microcorona discharge on a single dielectric barrier and applied it to inactivate microorganisms that commonly attach the rice seed husk. The cold-plasma treatment modified the surface of the rice seeds, resulting in accelerated germination and enhanced water imbibition. The treatment can operate under air-based ambient conditions without the need for a vacuum. The cold-plasma treatment completely inactivated pathogenic fungi and other microorganisms, enhancing the germination percentage and seedling quality. The final germination percentage of the treated rice seeds was ∼98%, whereas that of the nontreated seeds was ∼90%. Microcorona discharge on a single dielectric barrier provides a nonaggressive cold plasma that can be applied to organic materials without causing thermal and electrical damage. The hybrid nonthermal plasma is cost effective and consumes relatively little power, making it suitable for the surface sterilization and disinfection of organic and biological materials with large-scale compatibility.

Enhanced seed germination and plant growth by atmospheric pressure cold air plasma: combined effect of seed and water treatment

“…Plasma treatment can have a variety of effects on the morphology of seeds due to its complex interaction with organic materials and living cells. Another consequence of the plasma treatment is the modication of surface properties and sterilization of the seeds as reported by Khamsen et al 20 and Basaran and Akhan.…”

“…3,4,37,38 The improved germination by plasma discharge on the seed surface can be correlated to several factors such as increase in surface wettability, 14 killing of bacteria and pathogens on the seed surface. 20,21 In addition, the local heating probably opens up the seed coating and increases the water intake. The plasma discharge produced RONS such as O 3 , N 2 O and electrons have modied the water uptake rate and increased the germination metabolisms.…”

Cold plasma: a potential new method to manage postharvest diseases caused by fungal plant pathogens

“…Common gases used include air, modified air (Shi et al ., ) or noble gases such as argon (Khamsen et al ., ). The efficacy of CP is highly variable depending on the feed gas.…”

“…In general, pathogen inactivation efficacy increases with the increase in exposure to CP (Lu et al ., ; Herceg et al ., ). The distance of the produce or pathogen from the CP source also differs, ranging from 1 to 20 cm in in vivo experiments (Hayashi et al ., ; Khamsen et al ., ), and 0.5 to 1.5 cm in most in vitro studies (Panngom et al ., ; Herceg et al ., ; Table ). It is hypothesized that CP treatment duration and distance are correlated, as most reports (both in vivo and in vitro ) have demonstrated that longer distances required longer durations of CP treatment for effective pathogen inactivation (e.g.…”

“…In the postharvest pathology field, Khamsen et al . () used a hybrid plasma system to treat rice seed to completely inactivate seedborne fungi, although the fungal species controlled was not mentioned.…”