Fig. 3.

Melatonin-induced H₂O₂ generation is impaired by DPI or DMTU. Three-day-old alfalfa seedlings were treated with or without 10 μm melatonin (Mel), 1 μm DPI or 0.5 mm DMTU, or a combination of Mel with DPI or DMTU. (A, B) After treatment for 36 h, root tissues were loaded with 20 μm H₂DCFDA and regions of root mature zone were detected by LSCM. Scale bar (A) = 100 μm. Fluorescence is shown relative to control samples (Con). RU, relative units. Six individual samples were randomly selected and measured per treatment. (C) H₂O₂ content was determined by spectrophotography. Means and standard errors were calculated from at least three independent experiments with at least three replicates for each. In (B) and (C) bars with different letters denote significant differences (one-way ANOVA followed by Tukey’s multiple range test, P < 0 .05).