Unraveling surface chemistry: Enhancing radish seed germination via plasma activation

• Non-thermal plasma treatment significantly enhances radish seed germination and growth. • Advanced surface analysis techniques (ToF-SIMS, MALDI-TOF, and XPS) were used to investigate chemical changes. • Plasma activation increased soluble sugars, reactive nitrogen species (RNS) , and proline , promoting germination. • Plasma treatment effectively reduced germination inhibitors such as saponins and abscisic acid . • Improved seed surface hydrophilicity and sterilization contributed to better water uptake and germination rates. • Findings provide a potential eco-friendly and cost-effective solution for sustainable agriculture. Non-thermal plasma holds great potentials as a pretreatment method for improving the seed germination and seedling growth. However, there is a wide spectrum of opinions on its mechanisms. In order to clarify the mechanism for plant growth enhancement by irradiating seeds with plasmas, we aim to investigate the chemical and molecular change on the seed surface. The radish seed was irradiated by the atmospheric pressure dielectric barrier discharge (DBD) plasma device and investigated by using time-of-flight secondary ion mass spectroscopy (ToF-SIMS), matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) and X-ray photoelectron spectroscopy (XPS). Relative to the control group set at 100%, plasma treatment increased normalized ToF-SIMS intensities for soluble sugars, proline by 71% and 69% and of the phenolic compounds umbelliferone and p-coumaric acid by 63% and 79%. In contrast, the normalized intensities of the germination inhibitors saponin and abscisic acid decreased by 19% and 34%, and surface hydrocarbon fragments [CH] − , [CH 3 ] − and [CH 4 ] − decreased by 33%, 36%, and 42%, respectively. The mass spectrum provides useful molecular information to confirm new species formed on the seed surface, which results in well-explained mechanism of the improved germination of the radish seeds.