Figure 6.

NADPH oxidase-mediated spermidine (Spd)-induced accumulation of H₂O₂ in cucumber. (A) H₂O₂ content in leaves. (B) DCF-DA staining of H₂O₂ accumulation in stems. Bars: 300 μm. (C) Relative intensity of H₂O₂ fluorescence in (B). (D) H₂O₂ content in roots. (E) DCF-DA staining of H₂O₂ accumulation in roots. Bars: 300 μm. (F) Relative intensity of H₂O₂ fluorescence in (E). Cucumber plants were pretreated with 5 mM DMTU or 0.1 mM DPI for 3 h, then exposed to 75 mM NaCl with 1 mM Spd or 10 mM H₂O₂. After the treatment for 12 h, the leaves, stems, and roots were collected for the detection of H₂O₂ content. Results are presented as the means of 3 biological replicates (± SE). Means with the same letter did not significantly differ at P < 0.05, according to Tukey’s test. Three independent experiments were performed with similar results