The Effect of Plasma-Activated Water on Zea mays L. Landraces Under Abiotic Stress

A major challenge in the agricultural industry is finding innovative and sustainable methods that can lead to enhanced crop resistance to abiotic stress factors and increased productivity. Research in recent years has proven the potential of non-thermal plasma in various fields, including agriculture, with relevance in promoting plant growth and development, plant immune response to abiotic stress or pathogen resistance. In the present study, distilled water was activated using dielectric barrier discharge equipment; subsequently, plasma-activated water (PAW) was used to irrigate maize plants subjected to cold stress. Two different maize accessions were studied in this work, SVGB-11742 and SVGB-718, previously identified as highly and moderately resistant to cold stress, respectively. After plant exposure to cold and irrigation with plasma-activated water, morphological, morpho-agronomical and physiological parameters and molecular data were assessed. The two genotypes showed distinct, often opposing, responses to PAW treatment depending on the parameter assessed. Generally, the obtained data at the molecular level showed that treatment with PAW increased the expression of certain genes involved in growth and development of the SVGB-718 variant subjected to cold stress. Irrigation of plants exposed to low temperatures with PAW did not have the predicted effects at the morphological and even the physiological level regarding the concentration of assimilatory pigments and the cold test index. While morphological benefits were limited and genotype-specific, PAW induced significant molecular changes (upregulated stress-responsive genes in SVGB-718), suggesting a priming effect that may not have been captured in the short-term morphological assays. However, the results obtained represent an important background for future studies.