title: Gibberellin biosynthesis from gibberellin A12-aldehyde in a cell-free system from germinating barley (Hordeum vulgare L., cv. Himalaya) embryos.
abstract: Gibberellin (GA) metabolism from GA12-aldehyde was studied in cell-free systems from 2-d-old germinating embryos of barley. [(14)C]- or [17-(2)H2]Gibberellins were used as substrates and all products were identified by combined gas chromatography-mass spectrometry. Stepwise analysis demonstrated the conversion of GA12-aldehyde via the 13-deoxy pathway to GA51 and via the 13-hydroxylation pathway to GA29, GA1 and GA8. In addition, GA3 was formed from GA20 via GA5. We conclude that the embryo is capable of producing gibberellins that can induce α-amylase production in the aleurone layer. There was no evidence for 12β- or 18-hydroxylation and GA4 was neither synthesised nor metabolised by the system. All metabolically obtained GAs, with the exception of GA3, were also found as endogenous components of the cell-free system in spite of ammonium-sulfate precipitation and desalting steps.
authors.affiliation: Pflanzenphysiologisches Institut und Botanischer Garten der Universität, Untere Karspüle 2, W-3400, Göttingen, Federal Republic of Germany.
authors.forename: E
authors.initials: E
authors.lastname: Großelindemann
authors.forename: M J
authors.initials: MJ
authors.lastname: Lewis
authors.forename: P
authors.initials: P
authors.lastname: Hedden
authors.forename: J E
authors.initials: JE
authors.lastname: Graebe