IN VITRO PROPAGATION OF CALLISTEMON CITRINUS

Callistemon citrinus is a shrub with high ornamental value. It is highly recommended for use in the Urban Landscape as it is a pollution tolerant plant. Commercially it is propagated by shoot tip cuttings. Target of present work was the development a micropropagation protocol. In vitro cultures were initiated at higher percentages from one-node explants excised from the basal part of young softwood shoots of mature plants end of May, which were cultured on solid (8 g L^-1 agar) Woody Plant Medium (WPM) salts, with 100 mg L^-1 myo-inositol, 1 mg L^-1 thiamine, 0.5 mg L^-1 pyridoxine, 0.5 mg L^-1 nicotinic acid and 30 g L^-1 sucrose, supplemented with 1 mg L^-1 BA or 1 mg L^-1 NAA and 0.25 mg L^-1 BA. High in vitro shoot proliferation was taken when one-node explants excised from microshoots were subcultured in media with 0.25 mg L^-1 BA or with 0.5 mg L^-1 BA and 0.25 mg L^-1 NAA. One-node explants subcultured in media with only NAA gave one shoot and many roots. All microshoots rooted when transferred in a medium with 0.5 mg L^-1 NAA, while 0.5 mg L^-1 IBA induced lower rooting percentage (63%); the number of roots produced was also less in the IBA-medium. All plantlets were successfully acclimatized ex vitro in peat:perlite (1:1 v/v).