Effect of Exposure to Nonthermal Atmospheric Pressure Plasma on Surface Modification of Cereal Seeds

The influence of nonthermal plasma on the surface properties of spring wheat seeds was studied. For plasma treatment of seeds a source of volumetric nonthermal argon plasma based on glow discharge at atmospheric pressure was used. The discharge was created in an electrode structure with a multipointed sectioned cathode and a flat metal anode. Two batches of seeds were prepared, each batch containing 100 seeds. Seeds from one batch were exposed to plasma, while seeds from the other batch were used as controls. Wettability measurements and surface modification analysis by electron scanning microscopy were performed to evaluate the plasma effects on the seed material. It was shown that as a result of plasma treatment the surface of seeds becomes hydrophilic, which is characterized by a decrease in the contact angle and an increase in the surface energy of seeds. It was established that plasma exposure of wheat seed coatings leads to modification of the seed surface, which consists in the manifestation of a fine mesh morphology on the seed surface with different cell size and rather sharply defined boundaries; the etching effects on the seed surface increase with increasing exposure duration or discharge power.