Low-frequency glow discharge (LFGD) plasma treatment enhances maize (Zea mays L.) seed germination, agronomic traits, enzymatic activities, and nutritional properties

Background: Plasma technology is an emerging sector in agriculture. The effect of low-frequency glow discharge (LFGD) plasma at medium pressure (10 torr) on maize morpho-physiological and agronomical behavior was investigated in the current studies. The LFGD plasma act as a secondary messenger to improve maize production. This cutting-edge plasma technology can be used in agriculture to boost agronomic possibilities. Materials and methods: Maize seeds were treated with LFGD Ar + Air gas plasma for 30 s, 60 s, 90 s, and 120 s. The gas ratio of Ar + Air was 1:99. Plasma was produced with a high voltage (1-6 kV) and low (3-5 kHz) frequency power supply across the electrodes. The internal pressure was maintained at similar to 10 torrs with a vacuum pump in the plasma chamber. Inside the plasma production chamber, the gas flow rate was maintained at 1 L/min. Results: Effect of LFGD Ar + Air plasma on seed germination, and growth parameters including, shoot length, root length, fresh weight, dry weight, plant height, stem diameter, and chlorophyll were measured and in comparison with the control the parameter scores increased by 4.89%, 3.18%, 1.77%, 5.53%, 1.90%, 5.16%, 1.90%, 1.98%, respectively. The SEM image of the seeds surface demonstrated remarkable changes caused by plasma treatment. In roots, APX and SOD activities improved by only 0.022% and 0.64%, whereas, in shoots their activities showed a 0.014% and 0.25% increment compared to control. Further, H2O2, soluble protein, and sugar content increased by 0.12%, 0.33%, 2.50% and 1.15%, 1.41%, 2.99%, 1.16% in shoots and roots, respectively, while NO showed no significant changes in plants. Interestingly, notable improvement were found in nutritional properties (protein 0.32%, fat 0.96%, fiber 0.22%, ash 0.31%, grain iron 1.77%, shoots iron 7.61%, and manganese 6.25%), while the moisture content was reduced by 0.93% which might be useful in prolonged seed storage and the long life viability of the seeds. However, zinc (Zn) content in maize seedlings from plasma-treated seeds showed no significant change. Conclusion: The present study revealed that LFGD Ar + Air gas plasma is associated with the elevation of ROS in leaves and roots, which in turn improves the seed germination rate, agronomic traits, growth, enzymatic activity, and nutritional supplement in maize.