Climate change is increasing pressure on crop production, yield stability, and food quality. In this context, nanomaterials have been explored as tools to enhance plant stress tolerance. Among them, carbon quantum dots (CQDs) are widely studied because of their biocompatibility and tunable physicochemical properties. However, their role in plants remains insufficiently defined. This Opinion proposes that CQDs should not be regarded simply as nano-enabled growth promoters, but as tunable nanoscale interfaces capable of modulating plant-environment interactions under stress. Current evidence indicates that their effects can be organized into three interconnected dimensions: regulation of soil and rhizosphere processes, adjustment of light utilization and photosynthetic performance, and stabilization of cellular redox homeostasis. These processes are mechanistically linked and converge at shared redox and signaling nodes. At present, available studies remain fragmented and largely confined to controlled conditions. Long-term environmental fate, ecological safety, and field-level reproducibility require further validation. Future research should focus on structure-function relationships, predictive design, standardized evaluation, and scalable green synthesis routes. Under this framework, CQDs are better viewed as research platforms for dissecting and modulating plant stress adaptation rather than as ready agronomic inputs. • Carbon quantum dots are increasingly recognized as modulators at the plant–environment interface under climate change. • CQDs influence soil properties and rhizosphere processes in addition to their direct interactions with plants. • Optical properties of CQDs are associated with improved photosynthetic performance under suboptimal conditions. • CQDs are involved in the regulation of redox balance and stress-related metabolic responses in plants. • Reported biological effects of CQDs are highly context dependent, highlighting the need for cautious evaluation.
Huang et al. (Sun,) studied this question.