Impact of low-concentration atomic oxygen on germination characteristics of rice seeds

In seed treatment using atmospheric-pressure air plasmas, deconvoluting plasma-generated reactive species and elucidating seed response mechanisms for each species are crucial. We examined the roles of atomic oxygen and ozone in rice seed germination and found that irradiation with atomic oxygen (0.74 ppm) enhanced germination, whereas exposure to ozone (400 ppm) showed no effect. Protein carbonylation was altered under atomic oxygen irradiation but remained unchanged with ozone exposure. These results indicate that even at low concentrations, atomic oxygen exhibits high reactivity that triggers seed responses, highlighting its key role in germination enhancement.