High viability of dormant Malus buds after 10 years of storage in liquid nitrogen vapour.

Three hundred and sixty two Malus accessions from the Canadian Clonal Genebank of Plant Gene Resources of Canada were cryopreserved as dormant buds at the USDA-ARS National Center for Genetic Resources Preservation in 1996. According to grafting data collected on 165 of these accessions in 1999, 80 percent of the accessions had at least 40 percent viability. A subsample of these accessions was processed for cryopreservation by either adjusting the moisture content of the budwood sections containing dormant buds to 32 or 37 percent moisture (fresh weight basis) or by not drying the budwood sections (46 percent moisture fresh weight basis) prior to cooling.

Cryopreservation of Arabidopsis thaliana shoot tips.

Development of a successful shoot tip cryopreservation method for Arabidopsis thaliana L. will enable researchers to use molecular tools to study processes important for successful cryopreservation in this model organism. We demonstrate that Arabidopsis can be successfully cryopreserved using either plant vitrification solution 2 (PVS2) or plant vitrification solution 3 (PVS3) as cryoprotectants prior to rapidly cooling shoot tips in liquid nitrogen (LN).

Cryopreservation of apple using non-desiccated sections from winter-collected scions.

Winter vegetative buds of Malus species are cryopreserved at USDA-ARS NCGRP to backup genetic resources maintained by field collections. The method uses desiccation of nodal sections prior to cooling but is time and labor intensive, and can damage materials if excessive. Here we tested cooling sections without prior desiccation to improve the efficiency of handling.

Cryopreservation of Malus germplasm using a winter vegetative bud method: results from 1915 accessions.

Cryopreservation using a winter vegetative bud method is being applied to the Malus collection maintained in the field at the USDA-ARS Plant Genetic Resources Unit, Geneva, New York. Winter hardy materials are sent to the USDA-ARS National Center for Genetic Resources Preservation, Fort Collins, CO, for processing. To date 1915 accessions, representing 30 species and 16 interspecific hybrids, have been tested.

Cryopreservation of Salix species using sections from winter vegetative scions.

Twigs of Salix species are candidates for cryopreservation procedures because they become tolerant of freezing temperatures during mid-winter. We examined several variables in developing a two-step cryopreservation procedure for sections from these twigs. Samples of Salix triandra cooled to -30 or -35 degree C and then transferred to the vapor phase over liquid nitrogen gave the greatest percent shoot formation.