Plant regeneration from cell suspension-derived protoplasts of Primula malacoides and Primula obconica

Protoplasts were isolated from cell suspension cultures of Primula malacoid es cv. 'Lovely Tokyo' and P. obconica cv. 'Aalsmeer Giant White'. P. obconi ca protoplasts were embedded in 0.1% (w/v) gellan gum-solidified discs comp rising MS medium supplemented with 3 mg/l of 2,4-D or picloram, 0.1 mg/l of zeatin, 0.2 M glucose and 0.2M mannitol, and surrounded by a liquid medium of the same composition except for the addition of 0.1% (w/v) activated ch arcoal. The protoplasts formed visible colonies, which were transferred to the regeneration medium containing 30 g/l of sucrose, 0.1 mg/l of picloram and 2 mg/l of zeatin for shoot induction. P. malacoides protoplasts formed visible colonies when cultured in disc culture using 0.1%, (w/v) gellan Sum -solidified MS medium containing 5 mg/l of 2,4-D, 1 mg/l of NAA, 0.1 mg/l o f zeatin and 0.4 M glucose. Small calli were transferred to MS medium suppl emented with 5 mg/l of zeatin for shoot regeneration. The shoots of both sp ecies readily rooted on plans growth regulator-free 1/2 MS medium and succe ssfully acclimatized to greenhouse conditions. The protoplast-derived plant s showed some alterations in morphological characteristics from those of th e in-vitro-germinated control plants. (C) 2001 Elsevier Science Ireland Ltd . All lights reserved.