Influence of PAW on the Lettuce Growth and Formation of the Secondary Metabolites in Different Growing Conditions

The aim of this paper was to find out if PAW (plasma-activated water) irrigation treatment might have a positive influence on morphological parameters (number of leaves, head mass, rosette height, rosette width, and dry matter), microelements and macroelements content, and the formation of secondary metabolites (phenols, phenolic acids, flavonoids, antioxidant activity, and proline). Watering in two treatments (PAW 1 (150 mL added per watering) and PAW 2 (300 mL added per watering)) were completed four times. The experiment was conducted in inside and outside growing conditions. As a result of the experiment, it was established that PAW treatment had a positive effect on morphological parameters, nitrogen content, and the content of phenols, phenolic acids, flavonoids, antioxidant activity, and proline. In addition, it was discovered that growing in inside conditions for PAW 1 treatment gave 61.43% better results in mass in relation to outside conditions. Regarding the PAW 2 treatment, the results showed that the mass in inside conditions was 66.30% higher than in outside conditions. Comparing PAW 1 and PAW 2 treatment, it was found that PAW 2 treatment gave 6% more mass than plants under PAW 1 treatment. It can be concluded that there was a positive effect of PAW treatment on morphological parameters in relation to the control, but there was no significant difference between the treatments.