Copper nanoparticles alleviate cadmium stress in Solanum melongena through endogenous melatonin and regulation of some physiochemical attributes

Different chemicals and substances are often used to increase plant growth and production, and their efficacy is impacted by things like concentration and growth stage. This study aimed to investigate the impact of cadmium (Cd) stress on Solanum melongena L. and evaluate the potential alleviating effects of Cu-nanoparticles. The findings revealed that low concentrations of Cu-nanoparticles effectively protected S. melongena. from the adverse effects of heavy metal stress. Cu-nanoparticles exhibited a crucial role in plant physiology by stimulating enzyme activity and defense mechanisms. Furthermore, moderate concentrations of Cu-nanoparticles were observed to promote plant growth and increase chlorophyll content. Additionally, the treatments with low concentrations of Cu-nanoparticles resulted in reduced oxidative stress, as evidenced by decreased levels of hydrogen peroxide and malondialdehyde (MDA) content. Moreover, the application of Cu-nanoparticles positively influenced total soluble protein levels and relative water content. Furthermore, the Cu-nanoparticles treatment effectively alleviated Cd-induced oxidative stress and increased the concentration of melatonin. Antioxidant accumulation exhibited an increase under various treatments, with the moderate concentration of Cu-nanoparticles showing the most favorable impact. In conclusion, the moderate concentration of Cunanoparticles demonstrated promising effects in mitigating Cd-induced stress and optimizing the growth and physiology of S. melongena plants.