Large-scale in vitro propagation of giant reed (Arundo donax L.), a promising biomass species

Giant reed (Arundo donax L.), a promising energy crop, is vegetatively-propagated from fragments of stems andrhizomes. This may limit large-scale cultivation, since it is time-consuming and involves considerable cost and effort.Tissue culture is an alternative to conventional methods of vegetative propagation and may represent a useful tool forlarge-scale propagation of plants for biomass production programmes. This report describes a protocol for the largescalein vitro propagation of giant reed by adventitious bud formation. Stem nodes with dormant buds proved to bethe most effective to initiate in vitro cultures giving the highest percentage of differentiated shoots (77%) comparedto the other plant fractions tested. A sterilisation procedure using 5 g l-1 HgCl2 enabled the production of sterileexplants. Moreover, early results indicated that late Autumn excision dates not only gave a higher percentage of welldevelopedshoots ( > 80%), but also a lower level of bacterial contamination (15 - 20%). 6-Benzylaminopurine (BAP)at 3.0 mg l-1 was most effective in promoting shoot multiplication when added to a basal medium containingMurashige and Skoog (MS) macro- and micro-nutrients, Morel's vitamins, 30 g l-1 sucrose, and 7.0 g l-1 bacteriologicalagar supplemented with 1.0 mg l-1 indole-3-acetic acid (IAA) and 0.05 mg l-1 gibberellic acid (GA3). Rooting wassuccessfully induced on the same basal medium used for proliferation, modified by halving the MS macro-nutrientsand replacing BAP and the other growth regulators with 2.0 mg l-1 1-naphthaleneacetic acid (NAA). Successfulacclimatisation (> 95% survival) of plantlets was carried out, even in late Winter, in a cold greenhouse or undersimpler facilities such as shade nets.