Mechanisms Underlying the Synergistic Effects of Selenium Nanoparticles and Melatonin in Enhancing Arsenic Stress Tolerance in Bamboo

Abstract Aims : Arsenic (As) toxicity remains a critical challenge for plant growth and environmental health, necessitating innovative strategies to boost plant tolerance and alleviate its adverse effects. In search of effective countermeasures, this study emphasizes the synergistic role of selenium nanoparticles (SeNPs) and melatonin (ME) in mitigating As-induced stress in bamboo plants. Methods :150 mg/L SeNPs, and 150 mg/L ME were exposed to four concentrations of As (0, 80, 150, and 200 mg/L) individually and in combination in one bamboo species via Completely Random Design (CRD). Results : Arsenic exposure alone caused clear signs of toxicity by inducing cellular oxidation in plants, characterized by reduced biomass and photosynthetic pigments, alongside increased activity of oxidoreductase enzymes, lipoperoxidation, and membrane permeability. In contrast, SeNP and ME treated plants significantly enhanced bamboo adaptability by improving antioxidant defense mechanisms, nutrient uptake, water relations, and osmolytes while also modulating As uptake and translocation. The combined effects of SeNPs and ME outperformed those of either compound alone. Conclusions : Co-application promoted growth parameters, chlorophyll content, and overall plant health under As stress via an increase in plant enzyme capacity, nutrient availability, a decrease in As accumulation and translocation, and an improvement in osmolyte balance. This approach may support future efforts in phytoremediation and stress-resilient cultivation.