Understanding the regulatory mechanisms of nanomaterials on carbon metabolism in plants.

Agricultural nanotechnology offers innovative strategies to enhance crop productivity by modulating fundamental physiological processes in plants. Despite growing evidence that nanomaterials (NMs) can significantly promote crop growth, a standardized theoretical framework explaining the underlying mechanisms remains elusive. This review proposes a systematic framework to elucidate how NMs positively regulate plant carbon assimilation and partitioning to ultimately enhance crop yield. We categorize internal carbon flow into three interconnected modules:(1) inorganic-organic carbon inter-conversion (photosynthesis and respiration), (2) organic carbon intra-conversion (sucrose and starch metabolism, alongside amino acid and fatty acid metabolism), and (3) supporting metabolic processes (nitrogen and secondary metabolism) that supply essential substrates and energy. To enhance carbon assimilation, NMs must be strategically selected to improve photosynthetic light conversion efficiency, electron transport, and enzyme activities, promote fatty acid metabolism, and bolster the glutamine synthetase-glutamate synthase (GS-GOGAT) cycle in nitrogen metabolism. Furthermore, NMs can modulate root exudates and reshape the structure and function of the rhizosphere microbiome, which in turn establishes a feedback loop that influences plant carbon assimilation and partitioning. This review also addresses the critical trade-offs between the economic potential and environmental risks of NMs, providing essential insights for their sustainable implementation in agriculture. Collectively, it provides a mechanistic framework for understanding NMs-plant interactions, paving the way for the rational design of nano-agricultural tools for sustainable yield improvement.