Atmospheric pressure double Dielectric Barrier Discharge treatment of water and seeds for stimulation of germination and plants growth
Résumé
Non-thermal plasma (NTP) has been proven as an efficient technology for pollutant degradation and organic decontamination, surface modification, disinfection and ozone generation, etc. More recently, it is demonstrated that the NTP could be used for agricultural applications. Indeed, the plasma-activated water (PAW) has shown significant impacts on plant growth and also reduced the amount of water usage. Additionally, NTP assisted pre-sowing seeds treatment was shown to be ecologically safe and effective method for the improvement of seed germination and their resistance to diseases.
In this study, we focus specifically on plasma treatment of seeds and water to improve the seeds germination and the plant growth. A double Dielectric Barrier Discharge (d-DBD) reactor driven by sub-microsecond high voltage pulses (> 25 kV) was used to produce the reactive species in gas phase and then bubbled through the deionized water (DIW).
The activated water was then applied to Radish (Raphanus sativus), tomato (Solanum lycopersicum), and sweet Spain pepper (capsicum annum).
The amounts of reactive species was controlled by the plasma input energy (<10 mJ/pulse) at constant air flow rate (1 L/min) and HV pulse frequency (400 Hz). The gas phase was analyzed and quantified online using FTIR spectrometer, multi-gas and ozone analyzers.
In addition, changes in water chemistry; i.e. the electric conductivity, pH, nitrate (NO3-) and nitrite (NO2-) ions, hydrogen peroxide (H2O2), and temperature; following the plasma treatment were analyzed. The total concentration of nitrate, nitrite, and hydrogen peroxide were measured using digital photometer and test strips.