Plants were watered daily and fertilized weekly with a solution of 170 mg L-1 of soluble fertilizer (19N-19P-19K; Haifa Chemicals, Ltd.). After 18, 25 and 32 d the seedlings were sprayed with solutions of salicylic acid (Merck®)
prepared at three concentrations (1.0, 0.01 and 0.0001 µM).
Distilled water was applied as a control. Tween 20® was added to the solution as a surfactant.
A completely random experimental design was used with 10 replicates per treatment.
fertilized weekly