| Popis: |
More than 50% of Agave species are endemic to Mexico. Among them, Agave peacockii is listed within the list of threatened species that require special protection. In this work, we aimed at developing new supplementary strategies to achieve micropropagation and perform cryopreservation of in vitro-grown shoot-tips of A. peacockii. For multiplication, the addition of two cytokinins, 6-benzylaminopurine (26.6 μM) and kinetin (27.84 μM) to MS semisolid medium significantly favoured the morphogenetic response and produced the highest shoot generation (87.00±17.18) after 60 d of culture. This interaction was more effective than using the same growth regulators separately. Propagated and rooted plantlets were successfully acclimated with 100% survival and a normal morphological development during greenhouse performance. For cryopreservation, an optimized protocol following droplet-vitrification approach allowed obtaining 98% and 96% regrowth before and after cryopreservation, respectively. Shoot-tips were excised of in vitro-propagated plants, subjected to preculture on MS semisolid medium with 0.3 M sucrose for 1d, loaded in solution with 0.4 M sucrose and 1.6 M glycerol for 20 min, exposed to vitrification solution PVS2 for 15 min, and then, immersed in liquid nitrogen in droplets of PVS2 placed on aluminium foil strips. The vegetative growth of cryo-derived plants and of the in vitro propagated plants was compared under greenhouse culture conditions. No significant differences were detected in most assessed characteristics after 120 d of acclimatization. The results presented here constitute new viable biotechnological approaches for the in vitro propagation and long-term conservation of endangered Agave germplasm. |
