Effects of phytostabilized Zinc Sulfide nanocomposites on growth and Arsenic accumulation in Wheat (Triticum aestivum L.) under Arsenic stress

• Biosynthesized ZnS – Orange peel improved growth and biomass of wheat. • Zinc sulfide nanocomposite decreased arsenic accumulation in wheat tissues. • Zinc sulfide – Orange peel reduced arsenic toxic effects in wheat. • Zinc sulfide nanocomposite enhanced the activities of several enzymatic and nonenzymatic antioxidants. This study employed phytostabilized zinc sulfide (ZnS) nanocomposites, a novel and environmentally friendly material (orange peels), to mitigate arsenic (As) toxicity and its accumulation in wheat ( Triticum aestivum L. cv. Pishgam). Wheat plants were exposed to sodium arsenate (via fertigation) at concentrations of 75 and 150 mg/L. These treatments caused significant reductions in shoots and roots biomass, chlorophyll contents; with concomitant higher tissue As levels, oxidative stress markers, along with enhanced antioxidant enzyme activity, compared to non-stressed controls. Supplementation with ZnS nanocomposites at concentrations of 75 and 150 mg/L significantly reduced As accumulation in both roots and shoots and alleviated the As toxicity. This was evidenced by increase of up to 29% in shoot fresh weight, 76% in root fresh weight, 27% in foliar chlorophyll contents, 38% in proline levels, and 21% in total soluble protein contents. There was notable increase in zinc concentration (up to 122%) and enzymatic activities (peroxidase (POD) increased by 98%, ascorbate peroxidase (APX) by 28%, and catalase (CAT) by 39%) in plants exposed to ZnS nanocomposites levels of 75 and 150 mg/L compared to As-stressed counterparts. Furthermore, ZnS nanocomposites reduced the As accumulation in roots by up to 41% and in shoots by up to 30%, while enhanced the hydrogen peroxide (H 2 O 2 ) level by 80% under As stress. These findings highlighted the potential of ZnS nanocomposites (especially at 75 mg/L) as a phytostabilizing, non-toxic, and environmentally friendly solution to ameliorate As toxicity in wheat plants. This study further helps to enhance identify critical avenues for focusing on the integrated application of nanoparticles in soil management to promote sustainable agricultural practices.