Unraveling the Distribution, Metabolization, and Catabolism of Foliar Sprayed Carbon Dots in Maize and Effect on Soil Environment

The enormous potential of carbon dots (CDs) in agriculture has been widely reported, whereas their accurate distribution, transformation, and metabolic fate and potential soil health effects are not clearly understood. Herein, 13 C-labeled CDs ( 13 C-CDs) were sprayed on maize leaf, accumulated in all tissues, and promoted photosynthesis. Specifically, 13 C-CDs were internalized to participate in the synthesis of glucose, sucrose, citric acid, glyoxylate, and chlorogenic acid, promoting tricarboxylic acid cycle (TCA) and phenylalanine metabolism. Additionally, the catabolism of 13 C-CDs in vivo was mainly mediated by O 2 •– produced by oxidative stress. 13 C-CDs did not have an obvious impact on the soil environment at the overall level. The detection of 13 C signals in soil fauna suggested 13 C-CDs in soil food chain transmission. This study systematically described the exact fate of CDs in plants and potential soil ecological risks and provided a more comprehensive analysis and support for the potential advantages of CDs in agricultural application.