The role of melatonin and nitric oxide in enhancing growth, phytochemical production, and gene expression in Datura innoxia

The research aimed to investigate the effectiveness of melatonin (Me) and nitric oxide (NO) in improving the physiological, phytochemical, and molecular responses of Datura innoxia in in vitro settings. To achieve this, a factorial experiment was performed with two factors to evaluate the effects of Me concentrations with three levels (0, 0.25, and 0.50 µM) and nitric oxide at four levels (0, 25, 50, and 100 µM) on various aspects of plant growth, physiological characteristics, phytochemical compounds, and molecular responses in Datura innoxia . The results demonstrate that a specific concentration of Me and NO significantly enhances plant growth, improves photosynthetic efficiency, and modifies biochemical components, along with associated changes in gene expression. An increase in the activity of antioxidant enzymes was noted. Additionally, the application of Me and NO led to elevated levels of essential phytochemicals, such as total phenols, flavonoids, Atropine, and Buscopan, which are crucial for the medicinal attributes of Datura innoxia . Molecular analysis revealed a significant increase in the expression of the H6H and PMT2 genes following exposure to Me and NO treatment. Consequently, it can be concluded that a specific concentration of Me and NO may enhance biomass production, photosynthesis, antioxidant enzyme activity, phytochemical synthesis, and the expression of genes related to the synthesis of phytochemical compounds. However, an excessive increase in these bio-stimulants can negatively impact plant growth and production.