Figure 1.

Schematic outlining the separation of ABA, ABA-GE and Adducts I & II from xylem sap, and their release as ABA ex Adduct I, ABA ex Adduct II, ABA ex ABA-GE and free ABA, prior to subsequent derivatisation to pentafluoro-benzyl esters (PFB-ABA) (not shown but see text) for quantification by GC-MS. Horizontally paired rectangles represent key phase separations and are denoted as aqueous or organic accordingly. Abbreviations used: ABA, abscisic acid; ABA-GE, abscisic acid-glucose ester; D₄ABA, tetra-deuteratedabscisic acid; CTMABr, cetyltrimethylammonium bromide; DCM, dichloromethane; IPA, iso-propanol.