Seed Treatment with Cold Plasma Induces Changes in Physiological and Biochemical Parameters of Lettuce Cultivated<i> </i>in an Aeroponic System

Aeroponic plant cultivation is a novel technology explored for its potential in indoor farming. In this study we evaluated the effects of seed treatments with cold plasma on growth, physiological processes and biochemical parameters in two lettuce cultivars - green variety &#039;Perl Gem&#039; and red variety &#039;Cervanek&#039; cultivated in an aeroponic system for 45 days. Seeds were treated with low-pressure air plasma for 3 min (further denoted as LCP3) or atmospheric dielectric barrier discharge (DBD plasma) for 3 and 5 min (reffered to as DBD3 and DBD5 groups). We estimated the effects of seed treatments on parameters of seedling growth, photosynthetic efficiency, amounts of photosynthetic pigments, anthocyanins, total phenolic compounds (TPC), and antioxidant activity in leaves. Despite the observed effects on germination and early growth, seed treatments did not affect biomass gain or head/root ratio in both lettuce cultivars. Seed treatments increased the photosynthetic performance index and amounts of photosynthetic pigments in ‘Pearl Gem’ but not &#039;Cervanek&#039; leaves. Seed treatments enhanced the content of protective phenolic compounds and antioxidant activity in ‘Pearl Gem’, and anthocyanin content in &#039;Cervanek&#039; leaves, indicating potential to improve the nutritional value of the edible part of lettuce cultivated in an aeroponic system.