Biomass-derived carbon dots with light conversion and nutrient provisioning capabilities facilitate plant photosynthesis

Carbon dots (CDs)-enabled agriculture has been developing rapidly, but small-scale synthesis and high costs hinder the agricultural application of CDs. Herein, biomass-derived carbon dots (B-CDs) were prepared on a gram-level with low cost, and these B-CDs significantly improved crop photosynthesis. The B-CDs, exhibiting small size and blue fluorescence, were absorbed by crops and enhanced photosynthesis via light-harvesting. Foliar application of B-CDs (10 mg·kg−1) could promote chlorophyll synthesis (30–100 %), Ferredoxin (Fd, 40–80 %), Rubisco enzyme (20–110 %) and upregulated gene expression (20–70 %), resulting in higher net photosynthetic rates (130–300 %), dry biomass (160–300 %) and fresh biomass (80–150 %). Further, the B-CDs could increase crop photosynthesis under nutrient deficient conditions, which was attributed to the release of nutrients from B-CDs. Therefore, the B-CDs enhanced the photosynthesis via enhancing light conversion and nutrient supply. This study provides a promising material capable of enhancing photosynthesis for sustainable agriculture production.