Integration of Light, Temperature, and Hormonal Signaling in Plant Development Under Variable Environments.

Plant growth and development occur under environmental conditions in which light and temperature fluctuate across temporal and spatial scales, yet developmental outcomes remain stable and coordinated. Although light, temperature, and phytohormone signaling pathways have been extensively characterized, less attention has been given to how these signals are coordinated and integrated to regulate development under variable and often conflicting environmental conditions. While previous studies have primarily emphasized pathway-level interactions, this review focuses on how environmental signals are integrated to regulate developmental outcomes under variable conditions. We synthesize current understanding of light-temperature-hormone interactions and propose an integrative perspective in which environmental cues are coordinated over time and translated into regulated developmental outcomes rather than immediate, proportional responses. We suggest that developmental progression reflects transitions among permissive, restrained, and committed states differing in responsiveness, buffering capacity, and reversibility. Hormonal feedback networks and chromatin-based environmental memory further shape these states by integrating current environmental information with prior exposure. This conceptual view explains how plants filter transient fluctuations, delay development under unfavorable or conflicting cues, and stabilize developmental transitions once regulatory thresholds are crossed. By examining germination, elongation growth, branching, flowering, seed development, and stress-adaptive responses, we identify common principles underlying hormone-mediated developmental regulation. This integrative perspective provides a unifying view of how environmental signals shape developmental plasticity while maintaining stability, with implications for crop improvement and predicting plant responses under changing environments.