Reversal of ABA-Induced Stomatal Closure by Phenolic Compounds

Vanillic acid, gallic acid, salicylic acid, cinnamic acid, p-coumaric acid, ferulic acid, coumarin, chlorogenic acid, rutin and morin antagonize the ABA-induced stomatal closure. This suggests the possibility of a regulatory role of phenolic compounds in the stomatal mechanism. Stomata respond variably to the individual phenolic compound. Some, such as vanillic acid, promote the stomatal opening while others, such as coumarin, inhibit the process.