Measurement of plant hormones by liquid chromatography-mass spectrometry.

Abscisic acid (ABA) plays a number of key roles in the growth, development, and stress response of plants. For example, it is vital to a plant's response to drought stress, and is the signalling molecule responsible for closure of the stomata in order to promote water conservation. The hormone is rapidly turned over in plant tissue, mainly by oxidation or conjugation. Accurate and sensitive quantification of ABA and its metabolites has made a significant contribution to the knowledge of the role of this hormone, and also of its relationship to the induction of numerous ABA-induced genes in plants. High-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) has become an essential technique for the analysis and quantification of these compounds.