Cryopreservation of embryogenic callus of Arundo donax L.

Currently Arundo donax, a non-food perennial grass also known as giant reed, is getting increased attention due to its use in biofuel production and phytoremediation. The plant is traditionally propagated by rhizomes, stem nodes or embryo rescue, and none of these can fulfil today the increasing demand for its cultivation. Hence, establishment of embryogenic callus cultures has potential to speed up the propagation of selected genotypes. However, embryogenic callus requires periodic subculturing, which in turn may lead to gradual reduction of embryogenic potential. Cryopreservation offers a unique solution to this problem, as at the temperature of liquid nitrogen all the biochemical reactions are hampered, and thus the decay of cultures is avoided. Present study, therefore, aimed at developing an efficient cryopreservation protocol for Arundo donax embryogenic callus by comparing two different techniques, i.e., slow cooling and PVS2 vitrification. PVS2 vitrification proved to be the most efficient, with best post-thaw recovery of callus samples achieved when PVS2 was applied for 60 or 90 min at 0°C, prior to direct immersion in liquid nitrogen. The cryopreserved callus continued to grow normally in post-cryopreservation.