Climate change is increasing the frequency and intensity of overlapping abiotic stresses, making cross-tolerance a critical component of plant resilience. While single stress responses have been extensively characterized, plants in natural and agricultural environments frequently encounter simultaneous or sequential stresses such as drought–heat, light–drought, and drought–salinity, which trigger nonadditive and often unpredictable physiological outcomes that vary with stress intensity, timing, and species. This review synthesizes current understanding of the mechanisms underlying cross-tolerance, emphasizing how contradictory signals, stress timing, and physiological integration shape plant responses under combined stress. We highlight how stomatal regulation, leaf energy balance, hydraulic function, and photosynthetic processes, including PSII stability and Rubisco activase activity, interact to determine stress vulnerability. At the biochemical level, osmotic adjustment, redox buffering, and hormone-mediated signaling networks reprogram metabolism so that the plant allocates resources to protection and damage repair rather than to just growth. We further discuss how stress memory, priming, and shared signaling pathways such as reactive oxygen species, abscisic acid, and mitogen-activated protein kinase cascades contribute to enhanced tolerance across stress types. Finally, we examine the implications of cross-tolerance for crop improvement, including breeding strategies, genomic selection, genome editing, and emerging technologies such as nanopriming and high-throughput phenotyping. Bridging the gap between controlled environment studies and field performance remains a major challenge, underscoring the need for multi-stress field trials and integrative breeding pipelines. Together, these insights provide a framework for developing climate-resilient crops capable of withstanding the complex stress environments of future agriculture.
Olofintuyi et al. (Thu,) studied this question.