Gibberellins play a role in the interaction between imidazole fungicides and cytokinins in Araceae

Imidazole fungicides such as imazalil, prochloraz, and triflurnizole and the triazole growth retardant paclobutrazol promote the shoot-inducing effect of exogenous cytokinins in Araceae, such as Spathiphyllum floribundum Schott and Anthurium andreanum Schott. The mechanism of their action could partially be based on the inhibition of gibberellic acid (GA) biosynthesis, because administration of GA₃ inhibits the phenomenon completely in S. floribundum. Not only is the suppression of GA biosynthesis involved, but also the metabolism of endogenous cytokinins is significantly altered. Although the balance between isopentenyladenine, zeatin, dihydrozeatin, and their derivatives was shifted to distinguished directions by administration of BA and/or imazalil and/or GA₃, no correlation between these changes in metabolic pathways and the number of shoots could be found. The metabolism of BA was not significantly altered by adding imazalil to the micropropagation medium of S. floribundum.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - 9R-5P]DHZ 9--d-ribofuranosyl-dihydrozeatin-monophosphate - 9R-5P]iP 6-isopentenyl-9--d-ribofuranosyladenine-monophosphate - 9R-5P]Z 9--d-ribofuranosyl-zeatin-monophosphate - 9G]BA 6-benzyl-9--d-glucopyranosyladenine - 9G]DHZ 9--d-glucopyranosyl-dihydrozeatin - 9G]iP 6-isopentenyl-9--d-glucopyranosyladenine - 9G]Z 9--d-glucopyranosyl-zeatin - 9R]BA 6-benzyl-9--d-ribofuranosyladenine - 9R]DHZ 9--d-ribofuranosyl-dihydrozeatin - 9R]iP 6-isopentenyl-9--d-ribofuranosyladenine - 9R]Z 9--d-ribofuranosyl-zeatin - BA 6-benzyladenine - DHZ dihydrozeatin - ES⁺ LC-MS/MS HPLC coupled Electrospray Tandem Mass Spectrometry - f.m. fresh mass - mT 6-(3-hydroxybenzyl)adenine - IMA imazalil - iP isopentenyladenine - NAA 1-naphthalene acetic acid - NFT Nutrient Film Technique - (OG)9R]DHZ O--glucopyranosyl-9--d-ribofuranosyl-dihydrozeatin - (OG)9R]Z O--d-glucopyranosyl-9--d-ribofuranosyl-zeatin - (OG)DHZ O--d-glucopyranosyl-dihydrozeatin - (OG)Z O--d-glucopyranosyl-zeatin - PAR Photosynthetic Active Radiation - PBZ paclobutrazol - PRO prochloraz - TDZ thidiazuron - TRI triflurnizole - Z zeatin