Cryopreservation of seeds and in vitro-cultured protocorms of Oncidium bifolium Sims. (Orchidaceae) by encapsulation-dehydration

FLACHSLAND, E.; TERADA, G; SCOCCHI, A; REY, HY; MROGINSKI, LA; ENGELMANN, F

CRYO-LETTERS

Año: 2006 vol. 27 p. 235 - 242

0143-2044

Encapsulation-dehydration was employed for cryopreserving seeds and in vitro-cultured protocorms of Oncidium bifolium. Freshly harvested seeds, 120 days after pollination, were encapsulated in beads containing ½ MS medium with 3% sucrose and 3% calcium alginate and subsequently pretreated in agitated (80 rpm) liquid medium supplemented with 0.15 M sucrose (24 h) followed by 0.25 M sucrose (48 h), 0.5 M sucrose (24 h) and 0.75 M sucrose (24 h). The beads with seeds were dehydrated with silica gel for 5 h to 19.2% moisture content and immersed in liquid nitrogen for 1 h, thawed at 30 ºC for 2 min, post-treated using the same series of liquid media [0.5 M sucrose (24 h), 0.25 M sucrose (48 h), 0.15 M sucrose (24 h)], and recultured on ½ MS medium with 0.1M sucrose and 0.7% agar. As much as 4.8% of the cryopreserved seeds produced complete plants. In-vitro cultured protocorms were successfully cryopreserved following the same procedure, allowing 11.3% of them to produce plants.