Graduate Candidate North Carolina State University Raleigh, North Carolina
Body of Abstract: Nitrogen (N) is an essential plant nutrient in plants. Plants assimilate nitrogen in the form of nitrate (NO3-) or ammonium (NH4+) by specific membrane-protein transporters. Synthetic fertilizers containing NO3-, mainly produced by the Haber-Bosch process, require large amounts of energy. Non thermal plasmas represent new and sustainable technologies of producing nitrogen fertilizer. Plasma forms by ionization of a gas when applying a high electric field. Nonthermal plasmas are formed at room temperature and can be used to fix NO3- into water by ionization of N2 gas from ambient air. The resulting plasma-activated water (PAW) also contains varying concentrations of reactive oxygen and nitrogen species such as H2O2 which may be relevant to plant health. PAW represents an untapped potential for new sustainable fertilizers. In the field of plasma agriculture, studies have found certain chemistries of PAW can benefit plant growth, but there is no unified standard. Moreover, little is known about underlying plant molecular and physiological responses to PAW.
Our team is investigating whether plants respond differently to PAW when compared to other nitrogen fertilizers. Using a new protocol for PAW treatment, we identified an optimal chemistry when generating PAW from a VHF plasma source. Treatment of 3-day old seedlings with PAW results in 6% increase primary root elongation compared to plants grown under similar levels of NO3-, but this effect was diminished when PAW contained 0.1 - 0.5 mM of H2O2. This effect was not observed in plants grown in soil for 5 weeks with weekly PAW watering regime. Nonetheless, similar dry biomass and rosette area were observed in PAW-treated plants and plants grown under similar levels of NO3-, reinforcing PAW as a potential substitute to existing NO3- fertilizers. Results from current studies addressing the effect of PAW treatment on the root microbiome and plant hormones will be presented.