Seed cryopreservation of Cedrela odorata L.: germination and early nursery establishment

Abstract

Seed cryopreservation represents an alternative for the long-term conservation of forest germplasm, especially of intermediate or recalcitrant tropical species, whose viability declines rapidly under standard storage conditions. The impact of rapid freezing of Spanish cedar seeds in liquid nitrogen (L2N), on sensu stricto germination, and on the early stages of seedling development was evaluated. To this end, both dehydrated and non-dehydrated seeds were subjected to encapsulation/desiccation pre-treatments in the presence of various anti-vitrifying agents (LS, PSV2, and PSV3), prior to freezing. After thawing at room temperature, germination speed and capacity were compared, as were plantlet establishment, growth and survival after transplanting to the nursery. Results show that Spanish cedar seeds have the potential to survive fast freezing, although, in general, this had a damaging effect during the germination and early stages of plantlet establishment, being less severe in seeds that had not been encapsulated. However, the pretreatments favored plantlet survival in the nursery. The roots were the most affected organ, which led to a high shoot root dry weight ratio (S:R). It is concluded that Cedrela odorata seeds subject to rapid freezing have the potential to survive, germinate and produce plantlets that can be transferred to nurseries, although further fine tuning of the protocol is required to optimize response.