Rooting and acclimatization of micropropagated Hypericum perforatum L. native to Sicily

Hypericum perforatum L. is traditionally used as a medicinal plant because of its different bioactive compounds with documented antidepressant and anti-inflammatory activities. Plantlets' mass production with high content of these secondary metabolites has been enhanced through in vitro culture but the process has often been stopped at the multiplication phase. A study was conducted in order to set up an efficient in vitro rooting and acclimatization protocol of a H. perforatum Sicilian genotype well-adapted to south Mediterranean conditions. Aseptic nodal segments were cultured onto a Murashige and Skoog ( MS) basal medium supplemented with 4.44 mu M 6-benzyladenine for multiplication. Microshoots were then transferred onto specific culture media for in vitro rooting in order to evaluate the nutrients concentration and different auxins effect: full and half-strength hormone-free MS or supplemented with 5.7 mu M indole-3-acetic acid (IAA) or 4.9 mu M indole-3-butyric acid (IBA). Highest rooting rate was achieved on full-strength MS with IAA 5.7 mu M and on all half-strength MS media; higher number of roots was recorded on half-strength MS with IAA and full-strength MS with IBA 4.9 mu M; longest roots were measured on full-strength MS with IAA 5.7 mu M. Rooted plantlets were ex vitro acclimatized by transferring them into greenhouse in plastic pots filled with peat: perlite and sand: perlite mixtures (1:1, v/v) under mist: acclimatization rate was higher for rooted plantlets grown in sand: perlite substrate.