The Plant-to-Plant Circular Strategy: Coupling Photodegradation and Phytoremediation With Plant-Based Nanomaterials for Plastic Degradation.

The environmental recalcitrance of widely used plastics, exemplified by polyethylene (PE), creates a core remediation trade-off between efficient yet ecologically risky synthetic catalysts and benign but slow phytoremediation. To bridge this gap, plant-based nanomaterials (PB-NMs) as dual-function catalysts are introduced for a sustainable "Plant-to-Plant" circular strategy with Alfalfa (Medicago sativa L.). Synthesized from biomass via a low-energy process, PB-NMs achieved 16.09% PE degradation in 28 days under UV-A and 11.35% in 90 days within soil alongside alfalfa, which is the highest efficiency compared to two other commercial carbon NMs. Systematic variation of plastic film placement reveals preliminary evidence of concentration effects, spatial and temporal differences, and the dependence of NM catalytic activity on plants during degradation. Microbial and functional gene analyses further suggest that, depending on spatial and temporal conditions, PB-NMs can activate distinct degradative bacterial communities and oxidative pathways. Collectively, our findings suggest a safe, closed-loop system where PB-NMs, UV light, and alfalfa synergistically degrade PE with no detectable trophic transfer under the evaluated conditions. This biocompatible synergy could potentially enable decentralized, household-level plastic remediation, offering a conceptual pathway to transform a centralized burden into a scalable, eco-positive practice for the circular bio-economy.