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

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: 1st PAW generation from vapor and injection into the water, 2nd PAW generation using electrical discharge on the water surface and 3rd 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.