Physiological mechanisms of triggering and occurrence of a short-distance systemic (sub-systemic) oxidative burst (OXB) caused by induction of local OXB induced by the elicitor were investigated using potato tuber tissues. The sub-systemic OXB was detected as luminol-mediated chemiluminescence (CL) on the non-treated side of tissue slices following a transient appearance of local OXB on the other side directly treated with an elicitor. The sub-systemic OXB was not induced when the elicitor was applied in the presence of a radical scavenger. H2O2-catabolising enzyme, or inhibitors of activation of local OXB and NADPH oxidase (diphenyleneiodonium: DPI), Ca(2+) chelator and Ca(2+) channel blockers). Treatment with H2O2 solution rapidly caused the sub-systemic OXB, which was inhibited by the presence of the above inhibitors either during the treatment with H2O2 or detection of CL. These results suggested that the elicitor-stimulated sub-systemic OXB may be dependent on O2(-) generating NADPH oxidase activated by an unknown systemic signal stimulated by H2O2 generated via local activation of the NADPH oxidase