Encapsulamento e conservação via congelamento a -80ºc de embriões maduros de Butia capitata (Mart.) Becc

Abstract

The Arecaceae family is distributed in several South American countries. Within this family is the species Butia capitata (Mart.) Becc., Which is currently threatened by deforestation and predatory extraction, which eventually limits the establishment of banks. seeds. In order to solve problems arising from the difficulty of germination and the unevenness of seedlings formed in situ, in vitro propagation via embryo culture is a very important tool for Butia species. . The cryopreservation process is theoretically applicable to any regenerative tissue and has been successfully applied to various plant species using callus, apex, somatic and zygotic embryos and suspen- sive cells. In the case of cryopreservation, the use of synthetic seed technology, a biotechnological tool of easy production and manipulation of propagules, stands out, opening promising perspectives in areas such as germplasm exchange. Concurrent with the development of the synthetic seed technique other different ways of cryopreservation were developed, including encapsulation-dehydration and encapsulation-vitrification. The objective of the present study was to evaluate the use of encapsulation-dehydration and encapsulation-vitrification techniques, aiming at freezing preservation of the species Butia capitata and to evaluate the use of encapsulation in its germination. Ripe fruits of Butia capitata were collected from matrices located in São Gabriel / RS. The mesocarp and endocarp of the fruit were removed to obtain the almonds, excised with the help of a scalpel to rescue the embryos, which suffered a disinfestation using 0.25% sodium hypochlorite for 10 minutes and washed in water. sterile distilled for 10 minutes. For embryo encapsulation, 2.5% sodium alginate diluted in ½ MS medium was used and 0.1 M calcium chloride was used for its complexation. At T0, the embryos were inoculated with culture medium ½ MS. At T1 the embryos were encapsulated and germinated, T2 the embryos were encapsulated and exposed to -80 ° C, T3 the embryos were encapsulated, subjected to laminar flow silica gel dehydration for 4 hours and exposed to -80 ° C. ° C. At T4 the embryos were encapsulated, dehydrated to 0.3 M, and 0.6 M sucrose and then soaked in PVS3 solution. The treatments T3 and T4 were also subjected to a temperature of -80ºC for 4 hours and then thawed at 60ºC for 90 seconds. The germination percentages obtained were 91.7% and 70.8% for T0 and T1, respectively. The embryos of treatments T2, T3 and T4 did not germinate. We concluded that it was possible to obtain embryo germination only when there was no freezing, thus suggesting further studies for the cryopreservation of the species.