Effects of plant growth regulators on survival and recovery growth following cryopreservation

Studies on the effects of plant growth regulators (PGRs) on survival, recov ery and post-recovery growth of shoot apices following cryopreservation are limited. In this study, the effects of plant growth regulators in both the culture phase and the recovery phase of cryostorage were examined for the rare plant species, Anigozanthos viridis ssp terraspectans Hopper. Survival of shoot apices was not correlated to cytokinin or auxin treatments admini stered in culture media prior to cryostorage. In recovery media, the plant growth regulators, kinetin, zeatin (cytokinins), IAA, (auxin) and GA(3) wer e examined for their effect following cryopreservation, It was found that t he application of a combination of cytokinin and 0.5 muM GA(3) from day zer o was the most appropriate for obtaining vigorously growing plantlets follo wing LN immersion. This combination proved to be more effective than basal medium, zeatin or kinetin treatments.