Long-Range Signals Built upon Plant Structural Continuity

Plants generate long-range signals via complex mechanisms that integrate electrical, calcium, and chemical signals. While animals employ synaptic/neural connections for cell-cell and organ-organ signal transduction, plants depend on specialized structures, such as plasmodesmata and vascular bundles. This review examines recent advances in elucidating these plant-specific long-range signal mechanisms, emphasizing the initiation, propagation, and integration of diverse signals throughout the plant body. We highlight how the combination of traditional electrical potential measurements and modern bioimaging techniques, particularly genetically encoded fluorescent indicators, has improved our understanding of long-range signals in various plant species, including Arabidopsis thaliana, Mimosa pudica, and Dionaea muscipula. These technological advancements have enabled the development of integrated models that encompass biological components (e.g., ion channel activities), chemical mechanisms (e.g., compound diffusion), and physical processes (e.g., hydraulic signals). This integration offers new insights into how plants coordinate systemic responses across spatially distant organs.