Regulation Mechanisms of Carbon Dots in the Development of Lettuce and Tomato

Abstract

The regulation of plant growth and developmental processes by carbon dots (CDs) has been frequently reported. However, little is known about how CDs are related to the yield and nutritional quality. In this study, carbon dots, obtained by the hydrothermal method with l-cysteine and glucose, were systematically characterized and applied to lettuces and tomatoes in a hydroponic nutrient solution to comprehensively investigate the mechanism of regulation of plant development by CDs. We found that CDs could accelerate seed germination, promote root and hypocotyl elongation of seedlings by activating the expression of genes encoding aquaporin proteins, and enhance the yield and nutritional qualities of mature plants by promoting the absorption of mineral elements together with the enhancement of photosynthesis. These results provide systematic insights into the mechanisms by which CDs regulate plant development.

Nitrogen and Sulfur Co-doped Carbon Dots Enhance Drought Resistance in Tomato and Mung Beans

“…The O 1s spectrum of CDs (Figure 2L) and oxidized CDs (Figure 2P) fit with ∼531.3 and ∼532.4 eV peaks that are attributed to C−O and C−OH, respectively. 31 The relative level and chemical bonds of C, N, and S elements changed when CDs are oxidized, especially S changed more obviously than the other elements (Figure 2I−P). Chemical groups, such as thiol in cysteine, thioether in methionine, phenolic hydroxyl in tyrosine, and indole in tryptophan and imidazolyl, contribute to the antioxidant activity of amino acids.…”

The role of fluorescent carbon dots in crops: Mechanism and applications

“…In addition, the easy functional modification of the surface of CDs endows them with more application possibilities. In the preharvest process of crops, CDs with hydrophilic groups on the surface have been reported to promote seed germination, 37 regulate the synthesis of aquaporin in roots, 49 and promote the absorption of water and nutrients. CDs prepared with PEI as a precursor have been reported to deliver targeted disease resistance genes or biomolecules in crops 97,104 .…”

“…While studying the effects of CDs on crop growth, the cytotoxicity of CDs was explored, and the results showed low or no toxicity. 49,51,[97][98][99][100] Studies have shown that CDs can be degraded into plant hormone analogs after they were applied to plants, thus promoting plant growth. 36,37,101 However, the potential effects have been considered to be concentration-dependent, that is, low dose has a promoting effect and high dose has an inhibiting effect.…”

“…In the light reaction, the enhancement of light harvesting accelerates the electron transfer rate, which also promotes the process of carbon reaction. For CDs with high graphitization and weak luminescence intensity, they can also improve plant photosynthesis and yield by other ways, such as enhancing plant nutrient assimilation ability, 49 increasing plant chlorophyll content, increasing CO 2 assimilation and Rubisco enzyme activity in carbon reaction process 50,51 . Even the degradation products (plant hormone analogs and CO 2 ) of these CDs in plants can promote plant growth 37 …”

“…The phytotoxicity of CDs has not been fully and definitively described. While studying the effects of CDs on crop growth, the cytotoxicity of CDs was explored, and the results showed low or no toxicity 49,51,97–100 . Studies have shown that CDs can be degraded into plant hormone analogs after they were applied to plants, thus promoting plant growth 36,37,101 .…”