Survival of four accessions of Anigozanthos manglesii (haemodoraceae) seeds following exposure to liquid nitrogen.

This study investigated the survival of seeds from the prominent endemic Western Australian species Anigozanthos manglesii following exposure to liquid nitrogen (cryostorage). Seeds from four different accessions (collected in 1987, 1990, 1993 and 1998) adjusted to different water contents were tested for survival following cryostorage. Water content was a significant determining factor with survival of cryostored seeds declining rapidly at water contents above c. 18%. These water contents were deemed as critical water contents and were supported by DSC scans showing high endothermic peaks indicating ice crystallisation. In some instances, survival of cryostored seeds also declined at low water contents. Seeds from 1990 had a lower than expected survival compared to the other accessions. This may have resulted from the higher lipid content of seeds from this accession, or the reduced germination and vigour of these seeds prior to cryostorage.

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

Studies on the effects of plant growth regulators (PGRs) on survival, recovery 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 administered in culture media prior to cryostorage. In recovery media, the plant growth regulators, kinetin, zeatin (cytokinins), IAA, (auxin) and GA3 were examined for their effect following cryopreservation. It was found that the application of a combination of cytokinin and 0.5 microM GA3 from day zero was the most appropriate for obtaining vigorously growing plantlets following LN immersion. This combination proved to be more effective than basal medium, zeatin or kinetin treatments.

Cryopreservation of the australian species Macropidia fuliginosa (Haemodoraceae) by vitrification.

Somatic embryos were used to develop a cryopreservation protocol for Macropidia fuliginosa, a commercially-important species endemic to the south-west of Western Australia. Somatic embryos were allowed to develop from embryogenic callus for three weeks on an kinetin medium prior to processing. These were transferred and cultured on a agar solidified basal medium supplemented with 0 to 0.6 M sorbitol for 2 d prior to incubation in Plant Vitrification Solution Two (PVS2). Following this, embryos were then washed in 1 M sucrose solution (treated controls) or cooled in liquid nitrogen (LN). Cooled embryos were then warmed and washed in sucrose solution. Highest survival for cooled treatments (67.3%) was achieved by preculture with 0.4 M sorbitol, then incubation in PVS2. Further experimentation varying pre-culture duration (2 or 3 d) and incubation on either glycerol (0.8 M) or sorbitol (0.4 M) indicated that very high survival (90.6%) of embryos was achievable by adopting a 2 d preculture period on 0.8 M glycerol. The phenotype and growth rates of plants obtained using this protocol were similar to those of parent plants. This optimised procedure was then applied to tissue culture-derived shoot apices of the same clone also resulting in a high survival rate (84.4%).