Optimizing in vitro large scale production of giant reed (Arundo donax L.) by liquid medium culture

Tissue culture methods offer the potential for large-scale propagation of giant reed (Arundo donax L.), a promising crop for energy biomass. In previous trials, giant reed resulted particularly suitable to invitro culture.In this paper, with the final goal of enhancing the efficiency of invitro production process and reducing costs, the influence of four different culture media (agar or gellan-gum solidified medium, liquid medium into a temporary immersion system-RITA®or in a stationary state) on invitro shoot proliferation of giant reed was evaluated.Giant reed exhibited a particular sensitivity to gelling agents during the phase of secondary shoot formation. Gellan gum, as compared to agar, improved the efficiency of invitro culture giving more shoots with higher mean fresh and dry weight. Moreover, the cultivation of this species into a liquid medium under temporary immersion conditions or in a stationary state, was comparatively as effective as and cheaper than that into a gellan gum medium. Increasing 6-benzylaminopurine (BA) up to 4mgl-1 also resulted in a further enhancement of secondary shoot proliferation.The good adaptability of this species to liquid medium and the high multiplication rates observed indicate the possibility to obtain from a single node at least 1200 plantlets every six multiplication cycles (about 6 months), a number 100 fold higher than that obtained yearly per plant by the conventional methods of vegetative multiplication. In open field, micropropagated plantlets guaranteed ahigher number of survived plants, secondary stems and above ground biomass as compared to rhizome ones.