Copper nanoparticles together with cold atmospheric plasma improves the growth and physiological indices of Dracocephalum moldavica in hydroponic system

Abstract

This experiment was conducted to investigate the effect of copper nanoparticles and cold atmospheric plasma on growth and physiological indices of Dracocephalum moldavica herbal plant under hydroponic culture conditions. The factors investigated in this experiment were copper nanoparticles at four levels of zero (control), 25, 50, and 75 ppm and cold atmospheric plas-ma at three times of zero (control), 20, and 30 seconds. The results showed that application of cold atmospheric plasma led to an increase in the shoot height, root length, shoot dry weight, root dry weight, leaf area, chlorophyll a, chlorophyll b, total chlorophyll, soluble leaf protein; it also decreased proline content. In addition, there was no significant difference between cold atmospheric plasma at the two durations of 20 and 30 seconds. Moreover, compared with the control and non-nanoparticle copper treatments, the use of copper nanoparticles improved the measured indices; accordingly, when making its greatest effect, the use of copper nanoparticles led to 27.77% increase in shoot height, 73.76% in root length, 67.98% in shoot dry weight, 87.67% in root dry weight, 22.83% in leaf area, 76.19% in soluble leaf protein in treatment with 25 ppm of copper and 39.42%, 50%, and 42.36% increase in chlorophyll a, chlorophyll b, total chlorophyll, respectively in treatment with 50 ppm of copper nanoparticles. Considering the obtained results, it can be concluded that the use of 25 ppm of copper nanoparticles (due to the application of nanoparticle instead of non-nanoparticle copper) within 20 seconds of cold atmospheric plasma improves the growth and physiological indices of D. moldavica herbal plant under hydroponic culture conditions.