Zygotic embryos rescue for ex situ conservation of the palm Butia noblickii.

APARICIO, GUSTAVO; HOPECHEK, LUCAS; QUESNEL KIEFL, SOL; PIZZINI, CECILIA; THALMAYR, PEGGY; GIOMBINI, MARIANO; GATTI, MARÍA GENOVEVA; NIELLA, FERNANDO; ROCHA, PATRICIA

Cincinnati - Virtual

Simposio; Virtual Global Symposium and Workshop, Conserving Exceptional Plants: Cryobiotechnology and the Model of Oaks; 2021

Butia noblickii, commonly known as Bonpland´s palm, is a species endemic to the southeast of the province of Corrientes (Argentina) and has been described very recently. Its spatial distribution is notably fragmented, with an increasing risk of population patches becoming isolated due to human transformation of the landscape. According to IUCN (2010) criteria, its current conservation status should be categorized as Endangered. Several basic aspects of its biology, which would contribute to its in situ and ex situ conservation, are still unknown. The pronounced dormancy that delays the germination of seeds of the genus Butia, which may require more than two years to germinate, represents a limitation for natural regeneration. In many cases, this dormancy is related to the difficulty of the embryo to overcome the growth restrictions imposed by adjacent tissues. To generate a methodology for in vitro germination of zygotic embryos for subsequent encapsulation in sodium alginate, dehydration, and cryopreservation, we performed in vitro embryo culture assays under controlled laboratory conditions. A random sample of 40 seeds of B. noblickii, obtained from mature fruits, was disinfected with ethanol and bleach, and their embryos were mechanically extracted under magnifying glass. The embryos were cultured in vitro, in Murashige and Skoog nutrient medium, in dark conditions and at an average temperature of 30±02º C. When the first evaluation was carried out after 15 days of culture, 45% of the embryos were germinated as inferred from thickening and elongation of their cotyledonary petioles. After 6 months, the seedlings continued their normal development, with the formation of leaf sheaths and roots. Therefore, the exposure of the embryo to in vitro culture conditions allowed to accelerate the germination of B. noblickii (45% of germination in less than 1 month) and the normal development of seedlings. These results constitute a first step for generating a long-term ex situ conservation protocol by encapsulation and cryopreservation of zygotic embryos.