Comparison of droplet-vitrification and D-cryoplate for cryopreservation of date palm (Phoenix dactylifera L.) polyembryonic masses

摘要

In this work we tested the efficiency of two techniques, droplet-vitrification (DV) and dehydration (D) cryo-plate, for cryopreservation of polyembryonic masses (PEMs) of two date palm varieties, Sokary and Sultany. With DV, recovery of non-precultured, cryopreserved PEMs was nil without treatment with the PVS2 vitrification solution, which contained 3.3 M glycerol + 2.4 M ethylene glycol + 0.4 M sucrose + 1.9 M dimethylsulfoxide. Following PVS2 treatments between 15 and 120 min, it was comprised between 90.9-98.6% and 85.6-88.0% for varieties Sokary and Sultany, respectively, Sucrose preculture (3 days, 0.5 M) led to 21.1% recovery of cryopreserved PEMs of variety Sokary only without PVS2 treatment, and slightly reduced recovery in all other experimental conditions with both varieties, compared with noncryopreserved PEMs. Regrowth intensity of cryopreserved PEMs was generally lower with variety Sultany compared to variety Sokary. With the D cryo-plate technique, no recovery of cryopreserved PEMs was achieved without sucrose preculture. Sucrose preculture (3 days, 0.5 M) had a positive effect on recovery of cryopreserved PEMs. For variety Sokary, the highest recovery (92.0-95.8%) was achieved for desiccation periods between 60 and 120 min. Recovery was between 67.0 and 74.6% after desiccation periods of 90-120 min for variety Sultany. With the D cryo-plate technique, regrowth intensity of cryopreserved PEMs was higher with variety Sokary compared to variety Sultany. (C) 2014 Elsevier B.V. All rights reserved.