Salicylic acid synthesized
in cells can move freely in and out of the cells, tissues and organs
(Kawano et al., 2004) and this movement is finely regulated by ROS
and Ca
2+
(Chen and Kuc, 1999; Chen et al., 2001). Supplementation
of tobacco cell suspension culture with higher concentration of salicylic acid resulted in ade novoinduction of SA excretion across the
membrane which was mediated by the generation of ROS and activation of a cascade of Ca
2+
signaling and protein phosphorylation.