Investigating plasma activated water as a sustainable treatment for improving growth and nutrient uptake in maize and pea plant

Abstract

In this study, an atmospheric pressure air plasma jet (APAPJ) was employed to generate plasma-activated water (PAW), which was applied to treat maize (monocot) and pea (dicot) seeds for evaluating its influence. This research explored APAPJ diagnostics by varying the air feed rate as 1, 2, and 3 liter per minute (Lpm) through current-voltage characterization, optical emission spectroscopy, electron temperature and density, nitrogen metastable state density, and rotational and vibrational temperature of the plasma. Additionally, various reactive oxygen and nitrogen species (RONS) formed and physicochemical properties of PAW were analyzed by varying plasma treatment time from 0 to 8 min. Furthermore, the water uptake of maize (Zea mays) and pea (Pisum sativum) seeds were examined by the measurement of the contact angle. Results indicated that APAPJ has the capacity of fostering germination, growth, chlorophyll, phosphorus, nitrite, nitrate, ammonium ion and leaf area in plants significantly with an optimized 6 min treated PAW for maize and 2 min treated PAW for peas. Among various categories, seeds soaked in PAW and irrigated with PAW exhibited the most outstanding result in germination and plant growth. Non-thermal plasma showed promising green methods for enhancing plant growth and boosting nutrient content.

Keywords: Atmospheric pressure air plasma jet; Germination; Growth parameters; Nutrient analysis; Plasma-activated water; Reactive oxygen and nitrogen species.