Enhancement of Germination and Seedling Growth of Wheat Seed Using Dielectric Barrier Discharge Plasma with Various Gas Sources

The influences of non-thermal discharge plasma treatment on wheat seed germination and seedling growth were investigated using a dielectric barrier discharge (DBD) plasma system at atmospheric pressure and room temperature. DBD plasma with various gas sources (oxygen, air, argon, and nitrogen) was employed in this study. Germination characteristics, seedling growth parameters, surface changes of the seed coat, permeability, and soluble protein of the seedlings were measured after the DBD plasma treatments. The experimental results showed that moderate-intensity DBD plasma had active impacts on wheat seed germination and seedling growth. Germination potential significantly increased by 24.0, 28.0, and 35.5% after 4 min of the air plasma, nitrogen plasma, and argon plasma treatments, respectively, compared with the control; and the shoot and root length also increased; however, no enhancement was observed after the oxygen plasma treatment. Scanning electron microscope analysis showed that etching effects on the seed coat occurred after the air plasma, nitrogen plasma, and argon plasma treatments, which affected the hygroscopicity and permeability of the wheat seed. In addition, moderate-intensity DBD plasma could also activate several physiological reactions in wheat seed, resulting in the increase of soluble protein production in wheat seedlings.