Author: Nivetha Arulkumar
Arulkumar, Nivetha, 2025 Cold Plasma and Plasma-Activated Water for Enhancing Growth and Abiotic Stress Resilience in Wheat, Flinders University, College of Medicine and Public Health
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Climate change poses a major threat to global food security, with drought and heat stress being among the most destructive challenges for cereal crops such as wheat (Triticum aestivum). Current mitigation strategies like selective breeding and agronomic management have shown limited success under increasing unpredictable climatic conditions. This study explores cold plasma (CP) and plasma-activated water (PAW) as sustainable, non-chemical technologies to enhance wheat growth and resilience against abiotic stress. Cold plasma is a non-thermal ionized gas with high concentrations of reactive oxygen and nitrogen species (RONS) able to modify seed surface properties, increase metabolism, and promote germination. PAW is a water exposed to plasma discharge with RONS used as bio-stimulants and signalling molecules. The main hypothesis of this study is that treating seed with CP, followed by spray with PAW, promotes germination, growth, tolerance to drought, and drought combined with high-temperature stresses.
The wheat seeds were treated with CP generated using compressed air and nitrogen with 80W and 5LPM flow rate for 10 and 20 minutes. Greenhouse experiments included twelve treatment combinations involving CP-treated and untreated seeds, with either PAW or distilled-water sprays under non-stress, drought, and combined drought + heat stress conditions. Physiological traits such as germination percentage, biomass, and head emergence were measured and analysed. Also, biochemical assays such as Thiobarbituric Acid Reactive Substances (TBARS), Gamma-aminobutyric acid (GABA), and alanine were analyzed to evaluate oxidative and metabolic stress responses.
Cold plasma treatment also brought significant increases in root and shoot growth, especially at 10 minutes of treatment, without any negative effect on germination percentage. Different concentrations of polyethylene glycol (PEG) solution such as 15% and 30% PEG was used to mimic drought stress in wheat seeds. Under combined drought & heat stress (30% PEG & 37ºC) conditions, plasma treatment significantly improved germination percentage in wheat seeds. In greenhouse conditions, PAW reduced growth under optimal conditions but enhanced root and shoot biomass under drought, suggesting an environmental stress dependent biostimulatory effect. The combined CP + PAW treatment increased head dry weight and maintained membrane integrity under combined stress. TBARS results showed reduced malondialdehyde accumulation, indicating lower oxidative damage, while GABA and alanine assays revealed improved redox regulation and nitrogen balance.
In conclusion, combined effect of CP and PAW enhanced wheat germination, growth, and stress tolerance through physiological and biochemical priming. Based on the obtained results we can conclude that their effects were dose and environmental stress dependent, with CP acting as an efficient seed-priming agent and PAW serving as a secondary stimulant during stress. These findings support the integration of plasma technologies into sustainable agricultural practices to improve crop performance under adverse climatic conditions.
Keywords: Cold plasma, Plasma-activated water, Wheat, abiotic stress, Seed coat modification, Compressed air plasma, Nitrogen plasma, Greenhouse experiment, Oxidative stress, GABA, Alanine, TBARS assay, climate resilience, Combined drought and heat stress
Subject: Biotechnology thesis
Thesis type: Masters
Completed: 2025
School: College of Medicine and Public Health
Supervisor: Sunita Ramesh