Analysis of Possible Involvement of Local Bioelectric Responses in Chilling Perception by Higher Plants Exemplified by <Emphasis Type="Italic">Cucurbita pepo</Emphasis>

Macroelectrodes and electrophysiological setup were used in experiments with stems of 15-day-old pumpkin (Cucurbita pepo L.) seedlings for computer-assisted data recording. It is shown that local bioelectric responses induced by graded local chilling are similar to the receptor potentials of animals. These responses increase gradually with stimulus strength and trigger the action potential generation when a temperature threshold is attained. The excitation threshold of cells in seedling stems displays the phenomenon of accommodation. Parameters of local bioelectric responses induced by intermittent cooling can undergo changes similar to sensitization-habituation patterns. The results indicate that local electrical responses may be involved in early stages of cooling perception in cells of higher plants devoid of locomotive functions.