Diffusion of 14C-Flurprimidol in Various Carriers Through Excised Silver Maple Bark

Abstract

Bark banding is one alternative to trunk injection of tree growth regulators (TGRs). The objective of this study was to compare the penetrability of various oils as carriers for a TGR applied to the bark. Five p.l of 14C-flurprimidol (225,000 dpm) and unlabeled flurprimidol dissolved in isopropyl alcohol and selected oils (Androc Basal Oil, ArborChem Basal, Arborchem Clean Cut, CWC Hy-Grade I, Exxon Aromatic 200, Exxon Orchex 796, Leffingwell Carrier #9, and N.G. Gilbert Riteway Oil) were applied to bark excised from silver maple (Acer saccharinum ). Bark discs, 1.35 cm diameter, were sealed in a diffusion chamber and the rates and amounts of 14C-flurprimidol that moved through the bark were measured by liquid scintillation spectrometry. Rate of diffusion, measured as dpm/day for nine days, was similar for each oil. The pattern of penetration was an initial flux the first 24 hours followed by a diminished rate of penetration by the end of day two and a gradual increase during the next seven days.