Quercus canariensis is a rare tree on the Iberian Peninsula whose distribution in Portugal is restricted to the Monchique mountains and the surrounding area. It is currently with the status of Critically Endangered (CR) according to the Red List of the Flora of Portugal and it is estimated that only 250 adult individuals are concentrated in that area. Considering the potential of in vitro systems to propagate and preserve plant material, a micropropagation protocol and a slow growth conservation experiment were developed. The establishment was done from seedlings, collected in Monchique mountains (37.317406 -8.543396). Following the establishment for shoot multiplication experiments, basal WPM medium was used, supplemented with different concentrations of benzylaminopurine. In these experiments, shoot tips and axillary buds were tested as explants. At this stage, the best results for both types of explants, were obtained using 1 mg/L BAP, with 2.3 as an average number of new shoots, with an average length of 23.9 mm for the shoot tips, and 2.6 as an average number of shoots with an average length of 22.0 mm for the nodal buds. Rooting was tested under both in vitro and ex vitro conditions, with the best results being obtained in vitro, using 3 mg/L IBA for 7 days, yielding a 92% rooting rate, 4.3 roots per shoot, with an average root length of 49.4 mm. The acclimatisation took place, initially, in polystyrene boxes, filled with peat, under controlled temperature, humidity and light conditions, and subsequently in an acclimatisation tunnel to an final ambient humidity of 50–60% during six weeks, with 85% of survival. In the slow growth conservation trials, different treatment times were tested, and viable explants were obtained after one year of cold storage.

As far as we know, this is the first protocol for the in vitro micropropagation and conservation of Q. canariensis, and we believe it could make an important contribution to the conservation of this endangered species