Abstract
In this study, we investigated the effects of plasma activated water (PAW), melatonin and nano-zinc on the secondary metabolites production in Cannabis sativa. We treated C. sativa plants cultivated in greenhouse with PAW, melatonin and zinc oxide nanoparticles (nZnO), either individually or in combination. After the simultaneous treatment of zinc oxide and melatonin, PAW was used as irrigation water on the plants under greenhouse conditions and the content and composition of secondary metabolites in the plant leaves were analyzed. After two weeks and harvesting the plants tissues, the secondary metabolites of the seedlings were measured in leaves. We found that the combined treatments of PAW, melatonin and nZnO resulted in the highest increase of secondary metabolites including flavonoids, total phenolic compounds, alkaloids and terpenoids (CBD and THC). The enhancement of secondary metabolites was associated with higher relative leaf water content, membrane stability index, total chlorophyll content and nitrogenous compounds. Moreover, the combined treatment increased the and growth parameters of Cannabis sativa such as shoots and roots length, shoots and roots fresh and dry weight, indicating a higher potential for pharmacological and agricultural applications. Our results suggest that PAW, melatonin and nZnO can act synergistically to enhance the production of secondary metabolites in Cannabis sativa, by modulating the plant's physiological and biochemical mechanisms. The results of this research provide a new understanding of the regulation and optimization of the secondary metabolism pathway of Cannabis sativa by these factors, it also has several implications for optimizing the cultivation and production of cannabis.