Figure 4.

Effects of SHAM and DPI on SA-elicited O₂⁻ production in guard cell-enriched epidermal peels of Arabidopsis wild-type (WT) plants. A, Typical traces of the CLA chemiluminescence reflecting the production of O₂⁻ in the presence and absence of 2 mm SHAM (a peroxidase inhibitor) or 20 μm DPI (an NADPH oxidase inhibitor). SA at 0.5 mm was added at the time shown by the arrow. B, Total CLA chemiluminescence reflecting the production of O₂⁻ as recorded in A. Total RLU (relative luminescence units) is the sum of luminescence between 1 and 15 min. Each data point reflects the mean (n = 3). Error bars represent se. Values indicated by the same letter do not differ significantly at the 5% level, as determined by Tukey’s test.