The role of carbon dots in the life cycle of crops

The novel 0-dimensional quasi-spherical fluorescent carbon dots (diameter <10 nm) have the characteristics of small size, adjustable emission wavelength range, easy functional modification of surface groups, and good biocompatibility. Studies showed that it has great application potential in the entire life cycle of crops, including pre-harvest and post-harvest. Subsequently, crop waste can be used to prepare carbon dots and re-enter the crop life cycle. This review summarizes recent studies showing that carbon dots with specific chemical or optical properties can enhance crop yields in different ways. The small size and surface hydrophilic groups that can cross the plant cell barrier are beneficial to CDs to promote seed germination and absorb nutrients to promote growth. The high carbon content (>60%) endows it with potential as a nano-carbon fertilizer. CDs with positive surface charges or prepared by medium molecular weight PEI are the key to targeted delivery of fertilizers, pesticides, fungicides, DNA or RNA. The luminescence range of CDs covers the absorption range of plants and the electron donor and acceptor properties promote plant photosynthesis. The antioxidant properties of CDs are crucial for improving crop stress resistance. Photodynamic, photothermal, and UV absorption properties endow CDs with antibacterial and preservation applications. Finally, current challenges and future prospects are discussed.