title: Opening of Iris flowers is regulated by endogenous auxins.
abstract: Flower opening in Iris (Iris×hollandica) requires elongation of the pedicel and ovary. This moves the floral bud upwards, thereby allowing the tepals to move laterally. Flower opening is requires with elongation of the pedicel and ovary. In cv. Blue Magic, we investigated the possible role of hormones other than ethylene in pedicel and ovary elongation and flower opening. Exogenous salicylic acid (SA) and the cytokinins benzyladenine (N6-benzyladenine, BA) and zeatin did not affect opening. Jasmonic acid (JA) and abscisic acid (ABA) were slightly inhibitory, but an inhibitor of ABA synthesis (norflurazon) was without effect. Flower opening was promoted by gibberellic acid (GA(3)), but two inhibitors of gibberellin synthesis (4-hydroxy-5-isopropyl-2-methylphenyltrimethyl ammonium chloride-1-piperidine carboxylate, AMO-1618; ancymidol) did not change opening. The auxins indoleacetic acid (IAA) and naphthaleneacetic acid (NAA) strongly promoted elongation and opening. An inhibitor of auxin transport (2,3,5-triodobenzoic acid, TIBA) and an inhibitor of auxin effects [α-(p-chlorophenoxy)-isobutyric acid; PCIB] inhibited elongation and opening. The data suggest that endogenous auxins are among the regulators of the pedicel and ovary elongation and thus of flower opening in Iris.
authors.affiliation: Wageningen University and Research Centre, Agrotechnology and Food Sciences Group (AFSG), P.O. Box 17, 6700 AA Wageningen, The Netherlands. wgvandoorn@ucdavis.edu
authors.forename: Wouter G
authors.initials: WG
authors.lastname: van Doorn
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dole
authors.forename: Fisun G
authors.initials: FG
authors.lastname: Celikel
authors.forename: Harmannus
authors.initials: H
authors.lastname: Harkema
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000613:Aminobutyrates / Q000494:pharmacology; D003517:Cyclopentanes / Q000494:pharmacology; D035264:Flowers / Q000254:growth & development*; D005875:Gibberellins / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D007210:Indoleacetic Acids / Q000378:metabolism*; D031323:Iris Plant / Q000187:drug effects / Q000254:growth & development*; D009280:Naphthaleneacetic Acids / Q000378:metabolism*; D054883:Oxylipins / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000378:metabolism* / Q000494:pharmacology; D020156:Salicylic Acid / Q000494:pharmacology; D015026:Zeatin / Q000494:pharmacology
chemical_list: D000613:Aminobutyrates; D003517:Cyclopentanes; D005875:Gibberellins; D007210:Indoleacetic Acids; D009280:Naphthaleneacetic Acids; D054883:Oxylipins; D010937:Plant Growth Regulators; C011006:jasmonic acid; C030737:indoleacetic acid; D000040:Abscisic Acid; C014328:2-amino-4-phenylbutyric acid; D015026:Zeatin; C007842:gibberellic acid; D020156:Salicylic Acid