Cryopreservation of coriander (Coriandrum sativum L.) somatic embryos using sucrose preculture and air desiccation

An efficient protocol for cryopreservation of somatic embryos of Coriandrum sativum, an important spice and medicinal herb, was developed. The successful cryopreservation procedure utilized embryo clumps (ECs) comprised of 3–4 somatic embryos at the globular or heart-shape stage. These ECs were precultured for 3 days on medium supplemented with 100 g/L sucrose, desiccated under the current of sterile air for 100 min, then sealed in cryovials and plunged directly into liquid nitrogen. Preliminary incubation on sucrose-enriched medium (100 g/L) improved both desiccation- and cryo-tolerance of ECs compared to medium with normal sucrose content (30 g/L) and enhanced embryo formation after cryopreservation. The regrowth after cryopreservation and average number of new embryos developed from cryopreserved ECs were retained at the level of the untreated control (98% and 13 embryos per clump, respectively). Both normal and abnormal plants were produced from control and cryopreserved cultures, indicating that appearance of abnormalities was not related to cryopreservation. The regenerants with normal phenotype showed the same peaks of relative DNA content regardless of cryopreservation. The results suggest that simple desiccation method is effective for cryopreservation of coriander somatic embryos with subsequent regeneration.