Cold storage and efficient conversion of somatic celery embryos into transplantable plants

A method for the long-term storage of somatic celery (Apium graveolens L.) embryos was devised. Embryos survived well if stored slightly moistened at 4°C. Plants regenerated from somatic embryos, which were cold stored for up to 24 weeks, developed well and were morphologically identical to those regenerated from non-stored embryos. A culture procedure for maximizing embryo conversion was developed. Plant establishment was best if embryos and small plantlets were first grown in suspension culture with half-strength regeneration medium (RM) and then transferred to liquid half-strength RM with paper bridges or to a semisolid medium of agar mixed with perlite. The perlite allowed better penetration and aeration of the roots than agar alone or paper bridges. This procedure resulted in a 100% conversion of globular somatic embryos to plantlets in vitro. Subsequently, 143 out of total of 160 (89%) of these plantlets were successfully hardened ex vitro in mist and grown under field conditions.