In vitro propagation of Passiflora edulis through internodal segments as affected by medium composition

Abstract

The aim of the experiment was to evaluate the effect of the basal medium and the type and concentration of cytokinin on direct regeneration from internodal segments of passion flower (Passiflora edulis Sims). Internodal segment explants were cultured on the Murashige and Skoog (MS) and woody plant medium (WPM) without growth regulators or supplemented with 0.5–3.0 mg L-1 of 6-benzylaminopurine (BAP), thidiazuron (TDZ) or zeatin (ZEA). The cultivation of the internodal segment explants on media supplemented with cytokinins resulted in direct organogenesis without a callus phase. The shoot formation frequency and shoot number per explant were strongly influenced by the type and concentration of cytokinin. MS medium supplemented with BAP resulted in a shoot formation frequency that was higher in comparison with TDZ but significantly lower as compared to 0.5–2.5 mg L-1 ZEA. On the other hand, on WPM supplemented with BAP the shoot formation frequency was significantly lower in comparison with that for analogous ZEA and TDZ concentrations. The shoot formation frequency and shoot number per explant were strongly influenced by interactions of the basal medium and type and concentration of cytokinin. The MS medium supplemented with 2.0 mg L-1 ZEA resulted in the highest shoot formation frequency, while the highest shoot number per explant was obtained on WPM supplemented with 1.5 mg L-1 ZEA. The highest shoot formation frequency (98.1%) with the highest number of shoots per explant (9.53) was observed on the WPM supplemented with 1.5 mg L-1 ZEA. The formed shoots were rooted on MS medium containing 1⁄2 macro and micro salts supplemented with 2.0 mg L-1 IBA (indole-3-butyric acid); about 92% of them survived and grew normally with true-to-type morphology.