CHEMICAL INDUCTION OF ADVENTITIOUS ROOT-FORMATION IN TAXUS-BACCATA CUTTINGS

The effect of some auxins (IBA and NAA), phenolic compounds (phloroglu cinol, gentisic acid and coumarin), a combination of auxins and phenol ics, and a systemic fungicide (Bavistin) have been examined for stimul atory effects on adventitious root formation in stem cuttings (current season's growth) of Taxus baccata L. In general lower concentration ( 0.25 mM) of both IBA and NAA was more effective in inducing rooting of cuttings taken from both male and female trees. The combined treatmen t of IBA + NAA (0.25 mM each) showed some success in cuttings from mal e trees only (55%, compared to 15% rooting in cuttings from female tre es). Generally, the callus formation was quite high (greater than or e qual to 70%) in all auxin treatments (alone or in combination). Among the phenolics, 40% rooting success was achieved with phloroglucinol on ly, while coumarin and gentisic acid were ineffective. The combined tr eatment of auxins and phenolics also failed to promote rooting. On the other hand, Bavistin was extremely effective for callusing (greater t han or equal to 90%) as well as rooting (80%). The effectiveness of va rious compounds rested for rooting of young stem cuttings declined in the order: 0.25 mM IBA > 0.05% Bavistin > 0.25 mM NAA > 1.25 mM IBA > 15 mM phloroglucinol > IBA + NAA (0.25 mM each). In addition to the au xins, IBA and NAA that are widely used for commercial propagation, the auxin-like properties of the fungicide Bavistin could be exploited fo r adventitious rooting in T. baccata, and in other plant species.