Fig. 1

Changes in phenotype and biochemical characteristics during infection. A Changes in symptoms in P. davidiana × P. bollena leaves after infection with A. alternata. Images show the disease blotches at 0, 2, 3, and 4 DPI, with enlarged views of portions of infected tissue in the inset. B Lesion areas after infection. C Percentage disease index at 2, 3, and 4 DPI. D-F Contents of SA (D), JA (E) and H₂O₂ (F) in P. davidiana × P. bollena during different stages of infection. G-K Activities of CAT, SOD, POD, PPO and PAL during infection. The error bar represents the standard deviation of triplicate assays. Asterisks show significant differences between the inoculated and noninoculated leaves (**P < 0.01 and *P < 0. 05)