Figure 2.

Airborne resistance induction in lima bean under in vivo conditions. Plants were either treated directly with 0.5 mm BTH (direct treatment) or exposed to the air coming from directly treated plants (indirect treatment). Control plants were sprayed with sterile distilled water (direct treatment) or exposed to these controls (indirect treatment). A, Disease symptoms caused by virulent P. syringae of directly and indirectly treated plants versus the controls. B, The quantitative evaluation of the respective disease severity (no. of bacterial spots per leaflet). C, The growth response of the plants to the different induction treatments as number of nodes that the plants had produced 10 d after pathogen challenge. D, The population of P. syringae of the respective leaf disc (diameter = 1 cm). Bars represent means ± se. Sample size was n = 5 plants per treatment, and different letters indicate significant differences among treatments (P < 0.05 according to lsd). The experiment was repeated five times with similar results. [See online article for color version of this figure.]