Designing Ex Situ Conservation Strategies for <i>Butia capitata</i> [Mart. (Becc.) Arecaceae], a Threatened Palm Tree from Brazilian Savannah Biome, through Zygotic Embryo Cryopreservation

Jelly palm (Butia capitata) is a species of palm tree endemic to the Brazilian Savannah (Cerrado) Biome, which stands out for its use as food, which has resulted in a predatory exploitation of its natural populations. This study aimed to characterize fruits and diaspores of natural populations of jelly palm (‘Arinos’, ‘Mirabela’ and ‘Serranópolis’), in addition to developing ex situ conservation strategies of the species, through the storage of zygotic embryos at ultra-low temperatures of liquid nitrogen (LN). Initially, fruits, seeds and embryos were evaluated for their morphological characteristics. For conservation, hydrated zygotic embryos were desiccated for up to 12 h in a laminar-flow chamber and immersed directly in LN with different moisture contents. As a result, we observed morphological differences among the studied populations. The population ‘Arinos’ showed more expressive results for most of the evaluated characteristics, such as length, width of fruits and seeds. The cryopreservation of zygotic embryos proved to be efficient for the conservation of the species reaching germination rates between 70 and 86%, when the moisture content of the embryos immersed in LN were between 10 and 14%. The plants that reached the stage of the greenhouse had a rate of more than 80% survival. The variability in the characteristics of fruits and diaspores of the analyzed populations allow for establishing divergent groups for the definition of conservation strategies or genetic improvement. The developed cryopreservation protocol can be considered simple and efficient for the conservation of the genetic variability of the species