Cryopreservation of embryogenic tissues of Pinus nigra Arn. by a slow freezing method.

Six different embryogenic cell lines of Pinus nigra Arn. have been cryopreserved in liquid nitrogen using cryoprotection with sucrose (18%) and DMSO (7.5%). Post-thaw growth and tissue proliferation have been observed in five cell lines. The survival levels after storage in liquid nitrogen reached values between 62.5 and 100%. Growth of recovered embryogenic cells as well as somatic embryos is similar to the non-frozen tissues maintained in long-term culture. Somatic embryo maturation and plantlet regeneration occurred in all selected cell lines.