The effects of three plasma-activated water generation systems on lettuce seed germination

Abstract

Irrigation water treatment using plasma technology is a new approach to improve productivity. In this study the generation of plasma-activated water (PAW) as a novel subject in agriculture is investigated. Three water treatment systems were designed and evaluated: 1^st PAW generation from vapor and injection into the water, 2^nd PAW generation using electrical discharge on the water surface and 3^rd PAW generation in the aeration path into the water. The lettuce seeds were irrigated with PAW. The germination rate and mean germination time were measured after 6 days. The seedlings weight and the number of seedlings with a length of more than 3 cm were also recorded after 8 days. The results showed that PAW had a significant effect on the germination rate and length of seedlings. Electrical discharge on the water surface had the best results. Germination rate and the number of seedlings with a length of more than 3 cm increased by 11 and 36% respectively. While injection of plasma-treated air into the water significantly reduced the number of seedlings longer than 3 cm, compared to the control. In conclusion, the PAW application can improve some attributes of lettuce germination depending on the PAW system.