ENHANCEMENT OF SPROUTING AND ROOTING OF QUERCUS PUBESCENS BY BENZYLAMINOPURINE AND INDOLE-BUTYRIC ACID IN MICROPROPAGATION

Micropropagation has the advantage of genetic homogeneity and reduces difficulties related to ob-taining pathogen-free plant material. However, some plant species present challenging problems when used for in vitro culture. This research work dealt with the micropropagation of Quercus pubescens Willd. with the aim of enhancing the percentage pro-liferation and rooting from micro-cuttings. Micro-cuttings, containing apical or axillary buds, were taken from two year-old branches using a clone of Q. pubescens grown at the Forest Nursery of Sant’An-gelo in Vado, Pesaro-Urbino, Marche, Italy. A pre-liminary screening of the proliferation was per-formed using increasing concentration of benzyla-minopurine (BA) in the culture medium (0.25; 0.5; 0.75; 1 mg/l) in order to select the best hormones to use in the experiment. From the results it was possi-ble to deduce that BA plays a key role in influencing shoot proliferation, leading to the formation of a cal-lus and to the production of new shoots. Moreover, we observed that, especially higher BA concentra-tions promoted the production of a larger number of shorter shoots compared to low concentrations, that produced the small number of longer shoots. Fur-thermore, these trials have shown that, in order to have a large number of seedlings with an optimal shoot length, it is necessary to divide the process of propagation in two phases. The first phase involves a high concentration of BA, with the aim of increas-ing the number of new micro-cuttings; the second phase, with lower levels of BA, to increase the length of the shoots. With regards to root induction, the hor-mone selected was indole-butyric acid (IBA). Re-sults showed that micro-cutting exposed for 24h to higher hormone concentration gave the best results for root induction and root length. The study devel-oped an efficient method for the micropropagation of Q. pubescens for the selection of genotypes in in vitro and sterile (e.g., free microorganisms and in-sects) conditions. It is envisaged that the develop-ment of this protocol paves the way for further utili-sation of micro-propagated Q. pubescens in new ar-eas of research, such as in vitro mycorrhization.