Abscisic acid is a plant hormone. ABA functions in many plant developmental processes, including seed and bud dormancy, the control of organ size and stomatal closure. It is especially important for plants in the response to environmental stresses, including drought and salinity, by triggering stomatal closure, altering gene expression and metabolic fluxes, and coordinating osmoprotectant accumulation. At the biochemical level ABA is synthesized from carotenoid precursors via 9-cis-epoxycarotenoid cleavage by NCED enzymes, is perceived by PYR/PYL/RCAR receptor proteins that inhibit PP2C phosphatases and thereby allow activation of SnRK2 kinases, and is metabolized primarily by ABA 8-prime-hydroxylases (CYP707A family) to phaseic acid and downstream catabolites. Relevant physicochemical properties include formula C15H20O4, molecular weight 264.32 g mol minus 1, low aqueous solubility with good solubility in polar organic solvents, and stereochemical activity associated with the naturally occurring enantiomer.
Parent: Abiraterone
Parent: Abscisic Acid
Typical analytical specification for purified abscisic acid offered for research or technical use is purity greater than or equal to 98.0 percent by HPLC with total related compounds not exceeding 2.0 percent. Typical individual related compound limits are phaseic acid less than or equal to 0.5 percent, dihydrophaseic acid less than or equal to 0.3 percent, neoabscisic acid less than or equal to 0.2 percent, 8-prime-hydroxy-ABA less than or equal to 0.2 percent, and other isomeric or oxidative impurities combined less than or equal to 0.8 percent. Residual solvents are controlled to pharmacopeial or regulatory limits, moisture content is typically below 0.5 percent, and heavy metals are controlled to low ppm levels. Analytical methods used for these determinations include reversed phase HPLC with UV detection, LC MS for identity and trace impurity confirmation, and Karl Fischer titration for water.
Abscisic acid regulates developmental programs such as seed maturation and dormancy, modulates organ growth, and controls stomatal aperture to balance CO2 uptake and water loss; it also reprograms transcription and metabolism to enhance tolerance to abiotic stresses.
Not strictly; ABA can inhibit growth under certain conditions by restricting cell expansion and division, but it also coordinates adaptive development and maturation processes, so its effects depend on concentration, tissue context and interactions with other hormones.
It is called a stress hormone because its levels rise rapidly in response to abiotic stresses such as drought, high salinity and cold, and it activates physiological and transcriptional responses that increase plant survival under these stresses.
Another commonly used name is ABA; older literature sometimes refers to it as dormin, though ABA is the standard abbreviated name used in contemporary research.
