In Vitro Propagation Protocol for Porlieria chilensis: Efficient Ex Vitro Rooting and Acclimatization

Porlieria chilensis Johnst. (guayacán), an endemic Chilean species native to the sclerophyllous forests, is experiencing a significant population decline. Typically growing as a shrub or small tree on sunny slopes and rocky soils, its populations have been severely impacted by overexploitation and habitat degradation, leading to its classification as Vulnerable (VU). Mature, well-developed individuals have become increasingly rare, now mostly replaced by shrubby regrowth. This study presents the first reported in vitro propagation method for P. chilensis, aimed at establishing a protocol for its mass propagation. A 92.0% survival rate was achieved for nodal segments cultured on Murashige and Skoog (MS) medium after surface disinfection with 1.5% sodium hypochlorite for 15 min. Shoot elongation was successfully stimulated by supplementing the medium with 8.88 μM of 6-benzylaminopurine (BAP), resulting in an average shoot length of 6.9 cm. For ex vitro rooting, plants were transferred to 200 mL containers filled with a 2:1 (v/v) peat/perlite substrate. High rooting rates were obtained (87.5% and 93.1%) when treated with 1968 μM and 1476 μM of indole-3-butyric acid (IBA), respectively. Moreover, 89.8% of the plants survived acclimatization under controlled conditions. These results highlight the strong potential of in vitro propagation as an effective strategy for the conservation and restoration of P. chilensis populations.