Abscisic Acid
ab-SIZ-ik🔬 Anatomy●●● Advanced
Also known as: ABA
Abscisic acid (ABA) is the plant hormone responsible for stress responses. During drought, ABA signals stomata to close, reducing water loss. It also promotes seed dormancy and bud dormancy in autumn. In arboriculture, the growth regulator paclobutrazol increases ABA concentration, which helps trees tolerate drought and urban stress while slowing canopy growth near power lines.