Root architecture-informed nano-remediation strategy for nanoplastics toxicity in maize and soybean.

The pervasive accumulation of nano-plastics (NPs) in agroecosystems poses critical threats to crop productivity and food security. However, effective and targeted remediation strategies remain limited, particularly those that account for crop-specific traits such as root architecture, which may critically influence both nano-plastic uptake and the efficacy of nano-remedies. This study establishes a root architecture-informed nano-remediation strategy using manganese ferrite nanomaterials (MnFe2O4 NMs) to mitigate nano-plastics toxicity in maize and soybean. Through factorial experiments integrating foliar and soil NM delivery, we demonstrate that nano-plastics reduce biomass by 7.9-14.7 % via oxidative damage, photosynthetic inhibition, and metabolic disruption, with maize exhibiting greater susceptibility due to its shallow taproot system. Crucially, iron-based NMs reversed NPs-induced stress by 8.5-23.3 %, where soil-applied NMs optimized maize recovery (17.3 % shoot biomass increase) through direct root interaction and antioxidant activation, while foliar NMs maximized soybean resilience (23.9 % POD enhancement) via leaf antioxidant coordination. Metabolomic and physiological analyses revealed species-specific mechanisms: maize depended on NMs-mediated restoration of nitrogen assimilation and TCA cycle intermediates, whereas soybean leveraged architectural buffering and flavonoid-based stress mitigation. Structural equation modeling identified antioxidant capacity, photosynthetic efficiency, and root morphology as primary biomass regulators (path coefficients: 0.7-0.9). We further link these responses to rhizosphere metabolic reprogramming, where NMs upregulated nitrogen metabolism by 16-24 %, countering NPs-induced suppression of nutrient cycling. Our findings advance precision nano-agriculture by tailoring NM delivery to root architecture-soil application for fibrous-dominant crops and foliar strategies for tap-root species-providing a mechanistic framework for sustainable crop protection in contaminated soils.