Comparative study of germination in tomato seeds: Plasma-activated water vs. conventional water

Abstract

The food sector must pay attention to environmental pollution, resistance to pathogens and climate change, so as to provide healthy feeds for animal and man. Using atmospheric pressure plasma jets (APPJs) is one possible solution. Plasma can enhance germination process, increase agricultural yield, and decontaminate surfaces of food products and seeds. This study is to determine the effects of the plasma-activated water (PAW) produced by plasma jet discharge (PJD) system on in vitro grown tomato seeds. A plasma jet system is developed with a sine wave of an AC voltage peaking 12 kVA peak to peak and ranging to zero, a power of 60 W, and a frequency of 20 kHz. This procedure involves the treatment of 20 cc of distilled water (DW) through Direct Plasma activation, argon gas is supplied at a flow rate of 02 litres per minute. This creates a different pH and levels of reactive oxygen and nitrogen species RONS. The exposure of DW to PJD is done for a duration of five, ten and fifteen minutes to produce PAW. Plasma-activated water (PAW) promotes agricultural sustainability due to its rich content of reactive oxygen and nitrogen species (RONS), making it environment-friendly.  This investigation aimed to assess the impact of PAW produced by an atmospheric pressure plasma jet discharge (PJD) system on the germination and early growth performance of tomato (Solanum lycopersicum) seeds. The plasma jet, powered by argon gas at 2 L/min, activated distilled water (DW) while running in a 0–12 kV peak-to-peak, 20 kHz, and 60 W range. PAW is produced by exposing DW to plasma for 5, 10, and 15 min, which affected their concentration of RONS and pH values. The 160 seeds are divided into four groups that consist of three treated groups and one control group. Seven days are observed for germination percentage, germination rate and seedling growth parameters. PAW is significantly positive in germination kinetics and seedling development compared to DW, which is statistically significant (P < 0.01). The aforementioned study results indicate that PAW is a sustainable plasma process that improves germination and early growth in tomato seeds.