Characterization and Evaluation of Cold Atmospheric Plasma as Seedborne Fungal Disinfectant and Promoting Mediator for Physico-Chemical Characteristics of Moringa Oleifera Seedlings

Abstract

Large volume atmospheric pressure glow discharge plasma was developed and investigated to enhance the biological activities of M. oleifera seeds. The generated plasma was characterized optically, electrically, and spectroscopically. The large volume plasma size can reach 40 mm gape and 150 mm diameter. One hundred ns magnetic pulse compression high voltage system was used to generate the plasma where the current increases with increasing applied voltage at a constant frequency and discharge gap while the current decreases with increasing discharge gap at constant voltage and frequency. The plasma homogeneity was enhanced with higher applied voltage and frequency. Nitrogen second positive system bands dominated the plasma emission spectra, and its intensity increased with increasing applied voltage and frequency. There was a steady reduction in the total count of emerged seedborne fungi on the application of cold plasma with complete elimination of fungi at ≥ 13 A. The low doses of cold plasma (3.9 and 5.8 A) induced an increase in the seed germination, a significant increase in chlorophyll content (chl a and chl b) and antioxidant activities of the seedlings emerged from soaked or wet seeds rather than dry seeds. There was a steady reduction in the total count of emerged fungi reaching complete decontamination of seedborne fungi at higher plasma doses (≥ 13 A). The plasma was harmful when applied at higher doses (≥ 13 A) and more harmful to the wet seeds compared to the dry ones, where the chlorophyll a content of the seedling developed from 1% H2O2 soaked seeds.