• Carbon quantum dots (N-CQDs) significantly enhanced phosphorus uptake and utilization efficiency, and overall nutrient acquisition in potato. • N-CQDs application modulated root architecture, improved photosynthetic performance, and optimized key biochemical pathways. • The combination of medium P with 0.36 g L⁻¹ N-CQDs maximized PUpE, PUtE, and tuber yield. • N-QDs effectively mitigated P deficiency by enhancing ATP synthesis, protein accumulation, and starch biosynthesis. • Principal component and correlation analyses revealed strong positive associations among P uptake, photosynthetic activity, and yield-related traits. 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. Phosphorus and nitrogen doped carbon quantum dots (N CQDs) synergistically enhance potato PUE. The schematic model depicts how N CQDs facilitate soil phosphorus solubilization and uptake, thereby improving root system architecture, photosynthetic efficiency, biomass accumulation, and tuber yield under varied P regimes. This nano-agronomic interaction strengthens physiological and biochemical processes, enhancing nutrient utilization and sustainable potato productivity.
Shahzad et al. (Wed,) studied this question.