REGENERATION OF PLANTS FROM PROTOPLASTS OF ARABIDOPSIS-THALIANA L CV COLUMBIA (C24), VIA DIRECT EMBRYOGENESIS

This report describes a protocol for the regeneration of fertile plant s from mesophyll protoplasts of Arabidopsis thaliana race Columbia (C2 4). Regeneration was rapid and reproducible. The protocol is especiall y novel in that a large proportion of regenerating protoplasts regener ated via direct somatic embryogenesis. Protoplasts isolated from in vi tro-grown plants entered sustained division after 3-5 d in culture med ium and over a period of several days 6-22% of protoplasts underwent a t least one cell division. Approximately 2-16% of these protoplasts co ntinued to divide and after 3 weeks in culture had formed macroscopic colonies, of which 70-80% were regular embryo-like structures. Four we eks after release from the alginate culture matrix and transfer to sol id medium in the light, 68-88% of these structures had produced well-d eveloped shoots. Shoots could be maintained in culture or established in peat blocks. The regenerated plants were fertile.