BIOELECTROCHEMICAL SIGNALS IN POTATO PLANTS

Action and resting potentials were measured in potato plants (Solanum tuberosum L.) under different physiological conditions. External stimu li (e.g., raising the temperature, mechanical wounding, exposing plant leaves or soil to certain chemical compounds) caused action potential generation and lead to shifting the resting potential from its origin al steady-state level. The amplitude, polarity, and propagation veloci ty of action potentials depended on the type of external stimulus or s tress. The kinetics and amplitude of resting potential changes also de pended on the nature of external stimuli. In plants invested with leaf -feeding larvae of the Colorado potato beetle (Leptinotarsa decemlinea ta), the insect-induced action potentials moved downward along the ste m with a velocity of about 0.05 cm/s. The action potentials propagated downwards from the damaged leaf to the roots. When the upper leaves o f potato plants were sprayed with 0.3 ml of 1 mM pentachlorophenol aqu eous solution, the effect was nearly identical to that induced by Colo rado potato beetles.