Three experiments were performed aimed to evaluate the effect of jasmonic acid (JA), ethephon (ET) and acibenzolar-S-methyl (Bion®) (ASM) sprayed at 0.1 mM, 0.5 mM and 0.3 g L-1, respectively, on the components of resistance of tomato plants (cv. Santa Clara) to bacterial speck caused by Pseudomonas syringae pv. tomato as well as on the activity of peroxidases (POX), polyphenoloxidases (PPO), β-1,3-glucanases (GLU) and lypoxigenases (LOX). Only for experiment 3, the incubation period significantly increased by one day for plants sprayed with ASM compared to plants sprayed with water (control). For all experiments, the number of lesions per plant was significantly reduced by JA, ET and ASM in comparison to the control. For some evaluation times, POX, PPO and GLU activities were higher for JA; PFO, GLU and LOX for ASM; and GLU and LOX for ET in comparison to the control. In conclusion, in the presence of AJ, ET and ASM, bacterial speck symptoms were reduced and the activity of the enzymes POX, PFO, GLU and LOX increased.
Pseudomonas syringae pv. tomato; Solanum lycopersicum; acibenzolar-S-methyl; ethephon; jasmonic acid
