HPLC-DAD quantification of DIMBOA-glc, DIMBOA, and HDMBOA-glc in whole-tissue extracts (A) and apoplastic extracts (B) at 24 h after infiltration of leaf segments with 0.2% chitosan or mock buffer. Data represent means in μg g⁻¹ fresh weight (±sem) from three biologically replicated samples. Asterisks indicate statistically significant differences compared to mock-treated leaves (Student’s t test; α = 0.05). The experiment was repeated twice with similar results.