Effects of multifunctional cerium-doped carbon dots on photosynthetic capacity and nutritional quality of lettuce

Abstract

As biocompatible water-soluble nanomaterials, carbon dots (CDs) have attracted the interest of researchers in agricultural production. In this work, cerium-doped carbon dots (Ce-CDs) have been prepared as a water-soluble carbon nano-fertilizer using a one-pot hydrothermal method. The effects on lettuce yield and quality are investigated. The application of lower concentrations of Ce-CDs (50–150 mg L⁻¹) all contributes to lettuce yield and quality enhancement. 100 mg L⁻¹ of Ce-CDs demonstrates the most significant effect, increasing biomass by about 83.3% and promoting the accumulation of soluble sugars (87.5%) and soluble proteins (52.3%). Further investigation reveals that Ce-CDs can promote the electron transfer rate (33.35%), photosynthetic activity (30.28%), photoconversion efficiency (37.90%) and Rubisco activity (37.38%), and have a promoting effect on glutamine synthetase (GS, 3.10%) and glutamate synthase (GOGAT, 10.09%) activities. Regarding the net photosynthetic rate (54.99%), Ce-CDs elevate and induce stomatal opening and promote nutrient accumulation. This work not only evaluates the effects of rare earth-doped CDs as nano-fertilizers on plants but also provides strong technical support for the application of nano-fertilizers in practical production and life sciences.