Figure 1.

Average magnitudes of the metabolic component of the resting potential of cells of leaves in pea seedlings under control conditions and after preliminary treatment with fusicoccin (FC) and sodium orthovanadate (OV) (n = 6–10). The magnitude of the metabolic component, which showed H⁺-ATPase activity in the plasma membrane, was estimated on the basis of short-term changes in membrane potential after the action of the high OV concentration (see Section 4.2 and Figure S4 for details). The second mature leaves in seedlings were preliminarily treated with OV (0.5 mM) and FC (1 µM) treatments by incubation of the leaf (2 h) in solutions of these chemical agents; after that, these leaves were dried by filter paper and used for intracellular measurement of electrical activity. OV and FC were dissolved in standard solution (1 mM KCl, 0.5 mM CaCl₂, and 0.1 mM NaCl). Similar incubation in the standard solution was used as the control. *, difference between experiment and control plants was significant (p < 0.05).