Trichoderma-mediated iron oxide nanoproduct improves drought tolerance and carbon sequestration in industrial woody plants

Climate change is a major driver of abiotic stress, with drought being one of the most critical factors limiting the performance and productivity of industrial plants. Drought impairs key morphological, physiological, and biochemical processes, ultimately reducing biomass yield and carbon sequestration potential. Nanotechnology offers a promising eco-compatible strategy to counteract such stress, particularly through the application of biogenic nanoparticles. While iron oxide nanoparticles (Fe₂O₃ NPs) are widely studied due to their biological relevance and environmental abundance, the use of mycosynthesized forms—especially those derived from beneficial fungi—remains underexplored. In this study, a novel Trichoderma-mediated iron oxide nanoproduct was developed and applied to Quercus glauca, a woody species with industrial significance, under drought conditions. The nanoproduct was foliar-sprayed four times at weekly intervals. Treated plants exhibited significant improvements in shoot length, leaf number, chlorophyll a and b, total chlorophyll content, and stomatal conductance under severe drought. Ultrastructural analysis confirmed preservation of stomatal and root integrity. Additionally, the nanoproduct enhanced physiological resilience by increasing relative water content and suppressing drought-induced ROS accumulation, verified via DAB and H₂DCFDA staining. Enhanced antioxidant enzyme activity (SOD, POD, APX, CAT) further indicated activation of the plant's defense mechanisms. This study demonstrates the effectiveness of a fungus-mediated nanoproduct in enhancing drought resilience and carbon sequestration potential in Quercus glauca. These findings support the use of mycosynthesis as a sustainable and innovative nanotechnology approach for improving the performance of industrially valuable woody plants under climate-induced stress conditions.