Plasma-based treatments regulate seed germination in Cannabis sativa via oxidative status modulation and transcriptional changes

Cannabis sativa (hemp) is an industrial crop with expanding applications in the agrifood, textile, and pharmaceutical sectors. Despite its economic potential, seed germination and quality, essential for plant development and crop establishment, are suboptimal. In this context, plasma-induced seed priming represents a novel approach to improve germination efficiency. Although these treatments are rapid, their efficacy depends on the careful optimization of several operational parameters. Here, we aimed at developing optimized plasma priming treatments for hemp seeds by evaluating the influence of gas composition, operating pressure, and treatment duration. Two seed lots of a commercial hemp variety with distinct seed quality levels were used. The physiological effects on seed germination were determined by measuring several parameters (germination percentage, rate, and speed) while additional analyses included the levels of water uptake, surface hydrophilicity, chemical modifications, oxidative status, and selected gene expression profiles. Integrative data analysis revealed that oxygen-based plasma applied at high power intensity and short exposure time resulted in enhanced germination performance, likely due to increased hydrophilicity and subsequent water uptake. This treatment likely acted as a priming agent, stimulating pre-germinative metabolism, as evidenced by the transcriptional profiles of target genes. However, prolonged exposure resulted in detrimental effects possibly attributed to an excessive water uptake and ROS over-production. Overall, these findings suggest that properly calibrated plasma treatments can stimulate beneficial physiological responses and enhance germination, whereas excessive exposure disrupts cellular homeostasis and compromises seed performance.