Plasma-activated water (PAW) is a sustainable and innovative alternative for agriculture, especially in controlled environments like greenhouses. Tomato and pepper are key horticultural crops worldwide, with a considerable part of their production in greenhouses. This study examined the effects of PAW irrigation on seed germination, plant growth, and oxidative stress in tomato and bell pepper plants. PAW was activated for up to 15 min using a 1 L capacity plasma reactor based on a glow-type discharge in air with water-cathode. The concentration of nitrogen compounds and the energy efficiency of synthesis obtained with the reactor were moderately high (5.4 mM and 60 nmol/J, respectively). The most notable effects of PAW were observed in bell pepper. The germination percentage in bell pepper increased by up to 26%, while no significant effects were found in tomato seeds. PAW irrigation significantly promoted plant growth, with dry weight increasing by up to 61% in bell pepper and 42% in tomato. Lipid peroxidation results showed no oxidative damage in either crop. The biochemical analysis of antioxidant enzymes (catalase, superoxide dismutase, and guaiacol peroxidase) confirmed that plant defense systems responded adequately to PAW irrigation. These results highlight PAW’s potential as an innovative and eco-friendly alternative in agriculture.

In this study, plasma-activated water (PAW) was generated using a large-volume (5 L) plasma reactor with a quasi-stationary, water-cathode glow-type discharge in atmospheric pressure air. Tap water was activated up to 75 min. PAW exhibited high concentrations of long-lived reactive nitrogen species (RNSs), reaching 8 mM, which is between 4 and 26 times higher than those reported in previous studies. The reactor reached an RNS synthesis efficiency of 61 nmol/J and an RNS production rate of 526 μmol/min, both among the highest reported. PAW was evaluated on tomato and bell pepper. Seedling emergence was determined in a nutrient-free substrate. To assess plant growth, seedlings were transplanted into pots filled with either nitrogen-free or nutrient-rich substrate. PAW-irrigation significantly promoted seedling emergence and leaf expansion, especially in tomato plants. The plant growth-stimulating effects of PAW were more pronounced in nitrogen-free substrate: fresh weight of tomato and bell pepper increased up to 13.1-fold and 2.6-fold, respectively. In contrast, the effect on the nutrient-rich substrate was negligible. Tomato plants grown in the nitrogen-free substrate and irrigated with 75-min PAW reached a dry weight comparable to those grown in nutrient-rich substrate. PAW irrigation did not induce oxidative stress, as confirmed by malondialdehyde (MDA) levels and antioxidant enzyme activity.

Chickpea seed quality is highly susceptible to mechanical damage during handling and to rapid deterioration under postharvest storage. Atmospheric pressure Non-Thermal Plasma (NTP) has shown positive effects on seed quality in several species, but its long-term impact on chickpea remains poorly understood. This study evaluated the effect of NTP on the physiological germination process and postharvest deterioration of Cicer arietinum L. (Fabaceae) ’Felipe UNC-INTA’ seeds. Seeds were treated for three minutes with dielectric barrier discharge using O₂ and N₂ as carrier gases. Results showed that NTP optimized the triphasic germination response in embryo, especially in phases II and III, where radicle protrusion occurred earlier in treated (27 and 30 h) than in control (33 h) seeds, accompanied with a partition ratio < 1, indicating the roots’ preferential assimilate allocation. Fungal incidence decreased notably, e.g., Aspergillus decreased from 31% (control) to 11% (N₂) and 10% (O₂). O₂-treated seeds exhibited higher germination (94%) than the control (90%) and an 11% reduction in individual electrical conductivity, indicating enhanced membrane integrity. After six months of storage, both treatments delayed aging, maintaining higher vigor than untreated seeds. Overall, NTP emerges as a promising postharvest technology to enhance and preserve seed vigor and viability in C. arietinum.