Plant electrical signals: From scattered observations to functional understanding.

Plants generate electrical signals in response to a wide range of biotic and abiotic stresses, and these signals are increasingly recognized as important mediators of stress perception, systemic communication, and defense activation. While slow wave potentials induced by mechanical wounding and herbivory are relatively well characterized, the mechanistic understanding of many other stress-induced electrical responses remains limited. Nevertheless, electrical signals often represent some of the earliest detectable physiological responses in plants, highlighting their potential for plant phenotyping and early stress detection in agriculture. This review summarizes the different classes of plant electrical signals reported under stress conditions, their signal characteristics, physiological relevance, and proposed molecular mechanisms. We discuss their relationship with other signaling pathways, and review current electrophysiological recording approaches and emerging bioelectronic technologies for plant electrophysiology. Finally, we highlight key conceptual and technological challenges that currently limit mechanistic understanding of plant electrical signaling and discuss future opportunities for advancing the field.