TiO2 nanoparticles mitigate arsenic stress in maize: Impact on physiology, oxidative stress regulation, ionome, and yield resilience across varieties

Arsenic (As) contamination in agriculture poses a significant threat to crop productivity and food safety. This study examines the impact of arsenic and titanium dioxide nanoparticles (NPs) on maize growth, physiological responses, ionomic changes, and yield in two maize varieties, GD562 and GD911, at the V8 and VT stages. At both stages, NPs mitigated the negative effects of arsenic, especially in GD562. Growth parameters, such as plant height, leaf area, and biomass, improved in GD562 with NPs, whereas GD911 showed reductions under arsenic stress but exhibited some recovery with NPs. Photosynthesis and chlorophyll content in GD562 increased by 18 % at V8 and 17 % at VT for Pn, and by 18 % and 23 %, respectively, for Chl. Antioxidant enzymes (SOD, POD, CAT) were upregulated in GD562, with SOD increasing by 62 % at V8 and 40 % at VT. Reactive oxygen species (ROS) decreased, with H 2 O 2 reduced by 20 % at V8 and 11 % at VT in GD562. Ionomic profiling revealed a 35 % reduction in root arsenic and 50 % in grain arsenic in GD562 under NPs. Key ions, such as N, P, K, Ca, Mg, Fe, and Zn, accumulated more, particularly Ca, which increased by 35 % at V8 and 28 % at VT. TEM analysis showed a robust response in GD562, especially under NPs and combined (NPs + As) treatments. In GD562, yield increased by 23 % under NPS and 13 % under combined treatment. In contrast, GD911 experienced a 50 % yield reduction under arsenic stress but showed a 20 % recovery with NPs treatment. These results highlights the potential of NPs in enhancing maize resilience in arsenic-contaminated soils. • This study examines the impact of arsenic and titanium dioxide nanoparticles (NPs) on maize growth at V8 and VT stages. • NPs effects on maize physiology were assessed by evaluating growth, photosynthesis, and antioxidant enzymes. • Ionomic profiling measured arsenic uptake and nutrient accumulation under NPs treatment. • Transmission electron microscopy (TEM) analysed cellular responses to arsenic and NPs treatments. • The findings demonstrate NPs potential for enhancing maize resilience in arsenic-contaminated environments.