Abstract
This study evaluated the efficacy of cold plasma (CP) and plasma-activated water (PAW) in mitigating salinity stress on sweet pepper. Seeds were exposed to CP for durations of 0, 60, and 180 seconds, then irrigated with saline solutions at 0, 4, and 8 dS/m NaCl, and sprayed with tap water, potassium nitrate, or PAW. Results showed that increased salinity significantly hindered plant growth and fruit yield. i.e. declines were observed in leaf area, shoot dry weight, and productivity, by 18.67%, 19.11%, and 17.56%, respectively, at an 8 dS/m salinity level compared to non-salinity conditions. CP treatment significantly alleviated these adverse effects, especially at 180 seconds of exposure, which exhibited the most pronounced growth improvements and increased fruit yield by 16.81%, chlorophyll content (15.45 %), and productivity (38.17 %) compared to P0. Foliar application of PAW further enhanced growth and stress resistance. Additionally, CP and PAW treatments significantly increased the activities of antioxidant enzymes, specifically CAT and SOD, particularly under severe salinity conditions. The combination of salinity, plasma exposure, and plasma water treatment (P2W2S2) resulted in the highest overall CAT and SOD activity (0.9557, 169.23 U/mL, respectively), indicating enhanced mitigation of oxidative stress. Moreover, higher accumulations of osmoprotectants such as proline, vitamin C, and phenolic compounds were reinforcing the plant's resilience against salinity-induced oxidative damage. Overall, integrating CP seed priming and PAW proved to be a highly effective strategy for improving sweet pepper growth and productivity under saline conditions, emphasizing the potential of cold plasma technology as a sustainable agricultural approach.