Electrical signals in plants caused by external stimuli are capable of inducing various physiological responses. The mechanisms of transformation of a long-distance electrical signal (ES) into a functional response remain largely unexplored and require additional research. In this work, we investigated the role of calcium ions in the development of ES-induced respiratory response. Gradual heating of the leaf causes the propagation of variation potential (VP) in the pea seedling. The propagation of VP leads to a transient activation of respiration in an unaffected leaf. During the VP generation, a transient increase in the intracellular calcium concentration takes place. A calcium channel blocker inhibits the respiratory response, and a calcium ionophore induces the activation of respiration. Inhibitory analysis has showed that the VP-induced increase in respiration activity is probably associated with calcium-mediated activation of rotenone-insensitive alternative NADPH dehydrogenases in mitochondria.
Keywords: Calcium ions; heat stress; respiration; variation potential.