Cryopreservation of the embryonic axes of Phoenix reclinata, a representative of the intermediate seed category

The responses of the embryonic axes of Phoenix reclinata to some of the pivotal procedures employed for cryopreservation were investigated, the aim being to develop a cryopreservation protocol for germplasm of this species. This was undertaken by subjecting excised embryonic axes to flash drying to achieve partial dehydration, and thereafter to cryogenic storage temperatures by employing slow (1 degrees C min(-1), to -70 degrees C and subsequently rapidly cooled) and rapid (hundreds of degrees C s(-1)) cooling techniques, after which viability retention was monitored. The results showed that the embryonic axes of P. reclinata can withstand substantial dehydration in the short-term, allowing reductions in water content to as low as >= 0.05 +/- 0.03 g g(-1) (dry mass basis [dmb]) without any immediate detrimental effects on viability. Furthermore, these axes showed relatively good survival (>= 80%) using both slow and rapid cooling rates, when cooled at optimum water contents (between 0.21 +/- 0.12 and 0.25 +/- 0.06 g g(-1)). These findings indicate that cryopreservation offers a means for conservation of the germplasm of P. reclinata.