THE EFFECT OF PREFREEZING TREATMENT AND CRYOPROTECTANTS ON THE SURVIVAL OF CRYOPRESERVED SOMATIC EMBRYOS AND PLANT REGENERATION IN KOREAN NATIVE CITRUS SPECIES.

The highest rate of direct somatic embryos were induced on MT medium supplemented with 0.01 or 1.0 mg/l zeatin from the micropylar portion of ovule in Citrus junos, C. grandis and C. platymamma. Pretreatment with MS medium containing 10% dimethylsulfoxide (DMSO) and 1.0 M sucrose for 48 h, in liquid nitrogen (LN), yields the highest survival rate (92%) for preserving Citrus platymamma somatic embryo’s.

The most effective vitrification solution for cryoprotectant was a mixture of 10% glycerol, 10% ethylene glycol and 5% DMSO added, in MS medium containing 1.0 M sucrose.
In prefreezing treatment before plunging in LN, the gradual step freezing method, 0 &rarrow; -16 &rarrow; -32 °C, was effective for survival of preserved somatic embryos.
The direct immersion in LN showed less than 10% survival and few plant regenerated from the damaged cells of survived somatic embryos.
After preservation, healthy somatic embryos were observed, 80% plant regeneration, with the exception of low survival rate of somatic embryos in some treatments.

III International Symposium on In Vitro Culture and Horticultural Breeding

S. Oh

Citrus junos, Citrus grandis, Citrus platymamma, cryopreservation, cryoprotectant, prefreezing treatment, somatic embryos

https://doi.org/10.17660/ActaHortic.1997.447.100