Functional nanoparticles enhance wheat resilience to nickel toxicity through morpho-physiological, antioxidant, and agronomic modulation

Abstract

Introduction Nickel (Ni) contamination poses a serious threat to crop productivity by inducing oxidative stress and disrupting physiological and metabolic processes. This study explores green nanotechnology as a sustainable strategy for mitigating heavy metal stress to support climate-resilient agriculture (SDG 13). Methods We evaluated the efficacy of Withania coagulans –mediated, green-synthesized silver (Ag), copper oxide (CuO), and CuO-Ag bimetallic nanoparticles (NPs) in alleviating Ni-induced stress in two wheat ( Triticum aestivum L.) cultivars: SKD-1 and Borlaug-16. NPs were applied at 250 ppm via seed priming and foliar spraying. Results NPs treatments significantly improved photosynthetic performance; total chlorophyll reached 36.9 µg/g FW in SKD-1 and 21.1 µg/g FW in Borlaug-16. Antioxidant defense was reinforced, with superoxide dismutase activities up to 37 U/g FW and catalase activities up to 0.8 U/g FW, while malondialdehyde (MDA) content reduced to 1.3 µmol/g FW. Ni translocation was restricted via root sequestration, limiting grain accumulation to 0.2 mg/kg. Agronomic performance improved, with spike lengths of 12.4 cm, biological yields of 2.4 g/plant, and grain yields of 1.0 g/plant. Furthermore, phytochemical enrichment was observed, with total phenolics at 51.4 mg GAE/g DW and total flavonoids at 448.8 mg QE/g DW. Discussion CuO-Ag bimetallic NPs were the most effective in enhancing wheat resilience by limiting Ni translocation and sustaining yield. Future research should prioritize optimizing delivery strategies, elucidating molecular mechanisms of NP-mediated gene expression, and evaluating the scalability of these materials in diverse field-scale environments.