STOCK PLANT ETIOLATION AND STEM BANDING EFFECT ON THE AUXIN DOSE-RESPONSE OF ROOTING IN STEM CUTTINGS OF CARPINUS-BETULUS L FASTIGIATA

Experiments were undertaken to determine the effect of stock plant etiolation and stem banding, prior to cutting propagation, on the auxin dose-response of rooting in Carpinus betulus L. 'Fastigiata' stem cuttings. Stock plants were forced in a greenhouse, etiolated for 10 days and banded with black, light-tight Velcro(TM) for 8 weeks. Indole-3-butyric acid was applied to cuttings at concentrations ranging from 0 to 79 mM. Rooting percentages and numbers increased to a peak response at 20 mM in light-grown and 40 mM in etiolated shoots, followed by an inhibition at higher concentrations for all except etiolated and banded shoots. Cuttings prepared from shoots which had been etiolated or banded rooted better than controls at low and optimal IBA concentrations. Cuttings from shoots receiving both etiolation and banding also yielded higher rooting percentages and more roots per rooted cutting. Furthermore, etiolation and banding reduced the sensitivity of cuttings to supra-optimal auxin-induced inhibition of adventitious root initiation.