Deciphering phosphorus acquisition and partitioning in potato: Root architecture, physio-biochemical adaptations, and tuber quality modulated by carbon quantum dots

Phosphorus (P) fertilization is essential for sustaining global food security, yet its excessive use leads to economic losses and environmental concerns, necessitating alternative strategies to improve phosphorus-use efficiency (PUE). We hypothesized that nitrogen doped carbon quantum dots (N CQDs) act as a nanoscale facilitator to mitigate P deficiency and enhance P utilization, thereby maintaining metabolic stability in potato ( Solanum tuberosum L.). Plants were grown under low, medium, and high P regimes combined with N CQDs concentrations (0, 0.18, 0.36, 0.54, and 0.72 g l -1 ). Under medium P, N CQDs application significantly improved growth, photosynthesis, and biochemical dynamics. Biomass accumulation in leaves, stems and roots increased by 16–29%, while root length, surface area, diameter, and volume were enhanced by 9–21%. Photosynthetic rate, stomatal conductance, and transpiration improved by 33%, 12%, and 14%, respectively, alongside a 10% decline in intercellular CO 2 . Chlorophyll fluorescence and SPAD values were enhanced by 6–20% and 8%. Biochemical analysis revealed similar gains; tuber starch, ATP, and protein content increased by 17–38%, whereas proline and phenolics/flavonoids decreased by 18–23%. Consequently, nutrient partitioning analysis revealed that medium P with 0.36 g l -1 N CQDs achieved the highest leaf P concentration (31–56%) and P uptake efficiency (22%) over the low P control. Correlation and PCA analyses confirmed strong associations among P acquisition, root architecture, photosynthesis, and yield. Overall, N CQDs demonstrated a sustainable nano-enabled approach to boost crop productivity under limited phosphorus conditions. Future multi-omics studies will elucidate the molecular networks and regulatory genes involved in P metabolism, providing novel insights for root architecture and PUE.