Vitrification of shoot tips, nodal segments and embryogenic tissue of olive (Olea europaea L.) for germplasm cryopreservation

The study explores the possibility of olive (Olea europaea L.) germplasm cryopreservation, using both the vitrification and the encapsulation-dehydration procedures, followed by one-step freezing in liquid nitrogen. When shoot tips of olive (cv Frantoio) were incubated at 0°C in the PVS2 vitrification solution for 60 min, a 15% survival was recorded after direct immersion in liquid nitrogen and thawing at 40°C. More than 90% of encapsulated shoot tips and nodal segments survived after a 2-day preculture in 0.5 M-sucrose OM medium and a 4-hour exposure to silica gel, but the treatment was not effective in the protection of explants during ultra-freezing. Best results were obtained with olive embryogenic tissue (cv Canino), as 38% of samples survived to cryopreservation and showed enhanced morphogenicity.