Calcium ion secretion into the incubation medium from both apical and basal zones of vertically oriented maize (Zea mays L.) coleoptile segments was detected using a Ca²⁺-sensitive electrode. The apical zones of the coleoptiles were found to release considerably more calcium ions than the basal zones. This finding argues in favor of the existence of polar acropetal fluxes of this cation in shoot axial organs. The secretion of hydrogen ions was 5-10 times lower than that of calcium ions. The Ca²⁺ secretion manifested an oscillating mode with a period of about 60 min. Verapamil (0.06 mM), erythrosin B (0.1 mM) and LaCl₃ (1 mM) inhibited acropetal calcium transport to a greater extent than basal calcium transport. These results allow us to conclude that the transport systems located in the cellular membranes participate in the formation and retention of polar calcium fluxes in maize coleoptiles. The possible involvement of oscillating polar calcium fluxes in the spatiotemporal regulation of physiological processes in plants is discussed.