Novel insight at the Effect of Cold Atmospheric Pressure Plasma on the Activity of Enzymes Essential for the Germination of Pea (Pisum sativum L. cv. Prophet) Seeds

Great attention is currently being paid to the application of non-thermal plasma in agriculture. Seed germination is the first and critical time in the life cycle of each plant. Cold atmospheric pressure plasma (CAPP) generated by Diffuse Coplanar Surface Barrier Discharge, working at atmospheric pressure in ambient air, oxygen or nitrogen atmosphere in different time applications (60, 180, 300 s) was used to investigate its influence on early stages of germination processes in pea ( Pisum sativum L. cv. Prophet). For evaluation of physiological parameters germination, the imbibition rate, percentage of germination, germination potential, germination index, seeds and seedlings vitality index, and seedlings length index were determined. In this work, also CAPP influence on dehydrogenases and lytic enzymes (amylase, glucanase and protease) as well as genotoxic effects were studied. Infrared spectra of pea seeds surface demonstrate that reactive oxygen and nitrogen species as well as UV radiation produced in plasma cause oxidation of lipids and polysaccharides on the surface of samples and lead to increase of wettability related to increased imbibition which can accelerate germination. A significant positive effect had mainly CAPP generated in air and nitrogen atmosphere at treatment time of 60 s on the studied germination and growth parameters and overall activation of lytic enzymes in pea seeds compared to untreated control. Increased concentrations of radicals in young 3-day old seedlings and activation of antioxidant enzymes suggest that low plasma doses act as low stress, which paradoxically has a stimulating effect on germination, growth and development of seedlings.