Figure 5.

LOX activity in potato leaflets inoculated with P. infestans. Detached leaflets of cv Kennebec (resistance gene R-1) were inoculated with a sporangial suspension of P. infestans US940507 (US1, incompatible interaction resulting in resistance, ▴) or with ME93-2A (US8, compatible interaction resulting in susceptibility, ♦). Control cv Kennebec leaflets were inoculated with water (no interaction, ●). LOX activity (μmol O₂ s⁻¹ g⁻¹ protein) in leaves was determined by measuring oxygen consumption in protein extracts from pooled samples by using a Clark electrode for detection (Royo et al., 1996). Linolenic acid was added as a substrate and the pH of the reaction mix was 6.8. Each data point represents the mean of three measurements.