Determination of Time of Residency of Salicylic Acid Applied As Foliar Spray In Tomato Leaves (Solanum lycopersicum L.)

Some hormones, such as salicylic acid (SA) have been denominated elicitors or signaling compounds owing to its mediating action on the response of the plants to stress conditions. Salicylic acid has acquired great importance in the last decades due to its effects as diminishing stress compound, being with this, of importance, to determine the times of residency of SA into plants and the relationship with its profits on the plant growth. The present study was conducted to determinate the time of residency of salicylic acid in leaves of tomato (Solanum lycopersicum L.) when it was applied as a leaf spray under non-stress conditions. We analyzed the change in concentration of endogenous SA every two days after the foliar spray of 10^-4 molar of SA (138 ppm) and it was compared with a concentration of plants without application. In a first application, the endogenous SA in the spray plants presented higher concentration in comparison with the non-spray plants during eight days after application and it was found the highest level at the second day (being this value around 8 µg g^-1) to subsequently decreasing until obtain the same values of non-spray plants (around 4 µg g^-1). Interestingly, in a second application, the amount of endogenous SA in the spray plants only was higher than the non-spray plants during 4 days after application, having the highest level of SA at the first day after application (value around 8 µg g^-1) to subsequently decreasing until obtain the values under non-spray plants (around 2 µg g^-1). The increase in the concentration of SA when it was sprayed does not have an effect on weight fresh root and foliar area.