Approaches for the Cryopreservation of Plantago Algarbiensis, a Rare Endemic Species of the Algarve

BACKGROUND: Plantago algarbiensis is an endangered endemic species from the Algarve, Portugal. OBJECTIVE: The main goal of this study was to investigate the viability of cryopreservation procedures in the conservation of seeds and nodal explants from this species. MATERIALS AND METHODS: Seeds were directly immersed in liquid nitrogen (LN) for 30 days. Two methods were tested for the cryopreservation of nodal explants, namely droplet-vitrification and encapsulation-dehydration. For both methods, nodal segments were precultured on Murashige and Skoog (MS) medium and recovered on MS supplemented with 0.2 mg l^-1 6-benzyladenine (BA), after freezing. RESULTS: After 30 days in LN, the germination capacity of seeds was not affected. The regrowth percentages of cryopreserved nodal segments were approximately 60%. With the droplet-vitrification method, a regrowth percentage of 60.0 ± 15.2% was obtained after 120 min exposure to PVS2 (plant vitrification solution 2) and with encapsulation-dehydration method the highest percentage, 63.3 ± 9.6%, was achieved after 3 h desiccation. CONCLUSION: Seed cryopreservation and cryopreservation of nodal segments by droplet-vitrification and encapsulation-dehydration are therefore effective approaches for the conservation of P. algarbiensis.