抄録
Global climate warming has increased the exposure of agricultural ecosystems to extreme heat events, severely constraining crop yield formation and the stability of field production. As a key component of green agricultural technologies, novel biostimulants and exogenous protectants have emerged as research hotspots due to their capacity to enhance crop stress tolerance, promote metabolic homeostasis, and strengthen environmental adaptability. This review systematically summarizes the physicochemical characteristics, crop response patterns, and application progress of various emerging biostimulants—including nanomaterials, plant-derived signaling molecules, natural active extracts, and functional microorganisms—and highlights their roles in core physiological pathways such as hormone-mediated coordinated regulation, maintenance of reactive oxygen species homeostasis, osmotic adjustment and metabolic reprogramming, induction of heat-shock proteins and chaperone systems, and protection of photosynthetic structures and energy conversion processes. On this basis, key bottlenecks in current research are further identified and analyzed, including the complexity of biostimulant compositions and action targets, insufficient systematic understanding of mechanisms across cellular and population levels, and the incomplete evaluation of safety and field adaptability. The review also outlines future research directions, such as the integrated application of multi-omics and spatiotemporal dynamic monitoring technologies for mechanism elucidation, the design of smart delivery and precision slow-release systems, and the construction of coordinated “microbe–biostimulant–crop” response frameworks. Overall, this work aims to provide theoretical support and methodological references for the development of novel biostimulants, the regulation of crop thermotolerance, and the advancement of sustainable agricultural systems under increasing heat stress.
