Adventitious shoot regeneration from leaf and petiole explants of Campanula punctata lam. var. rubriflora makino

Abstract

A method has been developed for in vitro shoot regeneration from leaf and petiole explants of bellflower (Campanulapunctata) 'Jaju'. The influence of explant type, concentration of plant growth regulators and culture conditions on shoot regeneration were evaluated. Shoot bud formation occurred within three weeks either on the adaxial or on the abaxial surface without intermediate callus formation when explants cultured in MS medium with plant growth regulators. The highest frequency of shoot regeneration was achieved using petiole segments cultured on MS basal medium with 3.0 mg l(-1) BAP, 1.0 mg l(-1) IAA and 0.5 mg l(-1) NAA under a 16 h photoperiod, and photosynthetic photon flux at 30 mu mol m(-2) s(-1). Adventitious shoots were obtained from 56% of leaf explants and, significantly more efficiently, from 73% of petiole explants. Shoot elongation and rooting were enhanced in MS medium with activated charcoal (0.3%, w/v). Plantlets were successfully transferred to the greenhouse with 96% survival rate. This is the first report describing a detailed protocol for shoot induction through adventitious regeneration of leaf and petiole explants of Campanulapunctata var. rubriflora.