Figure 1.

Percentage relative pyranine fluorescence supernatant of inoculated cells as a measure of H₂O₂ production. Pyranine (10 μg mL⁻¹) was added to the supernatant of tobacco cells at the time of sampling the supernatant. Relative fluorescence of the supernatants of cv ‘North Carolina’ (NC) cells inoculated with Pn 9201 (compatible) or Pn 4974 (incompatible) zoospores was determined by dividing by the fluorescence observed in unchallenged control treatments at the same time point. Data represent means ± se of n = 6 from three experiments.