Chemistry of a colour test for abscisic acid
R. Mallaby, George Ryback · Journal of the Chemical Society Perkin Transactions 2 · 1972
Abscisic acid and its methyl ester are converted by acid-catalysed dehydration into neutral products, one of which has been identified as an unsaturated γ-lactone. It gives an intense violet-red colour with alkalis, which fades as the lactone is hydrolysed. This reaction is a useful qualitative test for abscisic acid.