Low-temperature plasma modulates seed germination through reactive oxygen species in dose-dependent manner.

Atmospheric pressure low-temperature plasma treatment has been shown to enhance seed germination in various plant species. However, whether plasma treatment modulates seed dormancy status or affects the seed germination process remains unclear. Additionally, most studies have primarily focused on the positive effects of plasma on germination and growth, without addressing dose-dependent responses or underlying molecular mechanisms. To elucidate the effects of plasma treatment on seed germination at a molecular level, we analyzed the germination phenotype of fully ripened Arabidopsis thaliana seeds under germination-inhibitory conditions following plasma treatment. We observed that plasma treatment enhanced germination potential up to a critical threshold, beyond which prolonged treatment diminished the enhanced effect. Chemical staining assays identified that plasma treatment induced the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) at different time points. Machine-learning aided modeling revealed that ROS, rather than RNS, plays a key role in plasma-mediated germination induction. Furthermore, transcriptome analyses suggested candidate genes likely modulated by plasma treatment during seed germination, including glutathione and L-phenylalanine metabolism, abscisic acid signaling, and the tricarboxylic acid cycle. Our study provides the first molecular-level insights into how atmospheric pressure low-temperature plasma modulates seed germination.