HABITUATION FORMATION INDUCED BY REPEATED COLD STIMULATION IN <EM>MIMOSA PUDICA</EM>

Memory formation, such as habituation and long-term potentiation, has traditionally been considered a phenomenon restricted to the nervous systems of animals. However, despite this prevailing view, ongoing debate exists regarding the possibility that memory may also be formed in non-neuronal systems. We investigated memory formation using Mimosa pudica, a touch-responsive plant model. We recorded electrical and behavioral responses to repeated cold-water stimulation by integrating electrophysiological recordings with quantitative behavioral measurements. Localized application of cold water reliably induced action potentials and leaflet folding; however, when cold stimulation was repeatedly applied to the same site, both action potential amplitude and behavioral response magnitude progressively decreased. By approximately the tenth stimulus, neither electrical nor behavioral responses were detectable. Mechanical stimulation applied at the subsequent trial restored both action potential generation and folding behavior, indicating that the observed loss of responsiveness was attributable to neither fatigue nor irreversible tissue damage. In addition to these short-term effects, plant regions subjected to repeated stimulation exhibited a sustained reduction in responsiveness to cold, which in some cases persisted for more than one week despite rest periods. Furthermore, pharmacological inhibition of ion conductance pathways showed that response attenuation was mediated through calcium influx, suggesting a contribution of ion conductance mechanisms. Together, these findings demonstrate that cold-evoked responses in Mimosa pudica are dynamically influenced by prior stimulation history. This study provides an integrated description of habituation in an excitable plant system and memory formation in non-neuronal systems.
This work was supported by NRF grant funded by MSIT RS-2025-00555096