Effetto di derivati dell'urea sulla radicazione avventizia in vitro di microtalee micropropagate di corbezzolo

Riassunto La radicazione avventizia è un passaggio chiave della propagazione vegetativa di specie di interesse forestale, agricolo, orticolo e ornamentale. Questo processo può essere stimolato mediante l’applicazione esogena di auxina ma il solo trattamento con auxine non è sempre in grado di stimolare la formazione di un apparato radicale funzionale. In questo lavoro è stato indagato l’effetto di due derivati ureidici di sintesi, coadiuvanti la radicazione avventizia, N,N’-bis-(2,3-metilenediossifenil)urea e 1,3-di(benzo[d]ossazol-5-il)urea, in microtalee recalcitranti di Arbutus unedo L. Abstract Adventitious roots are post-embryonic roots which arise from non-pericycle tissue in stem and leaves. Adventitious rooting is a key step in vegetative propagation of plants, as it is a prerequisite for the successful production of viable clones. Many environmental and endogenous factors, such as temperature, light conditions, hormones and tissue maturity, may affect adventitious root formation. Auxin has been shown to be intimately involved in the process of adventitious rooting. In fact, exogenous auxin application may stimulate this process in those cuttings in which it doesn’t occur naturally. But, sometimes, auxin alone isn’t able to reduce the woody plant recalcitrance and to achieve a high quality root system. Many efforts have been made to enhance rooting, investigating the effect of other natural or synthetic molecules. Two urea derivatives, the N,N’-bis-(2,3-methylenedioxyphenyl)urea and the 1,3-di(benzo[d]oxazol-5-yl)urea, that do not show any biological activity per se, can act as adventitious rooting adjuvants in several rooting systems. Here we report the effect of these compounds in recalcitrant strawberry tree (Arbutus unedo L.) microcuttings. Our results confirm the activity of these two compounds as enhancers of in vitro adventitious rooting process, in the simultaneously presence of exogenous auxin.