DORMANT BUD CRYOPRESERVATION: SECONDARY BUDS CAN AFFECT THE ESTIMATION OF POST-THAW SURVIVAL

Dormant, winter bud cryopreservation is an effective ex situ technique for genetic conservation that does not require resource-intensive in vitro facilities, opening opportunities for many field-based organisations.
A protocol for Malus (apple) developed in the continental climate of N. America was employed, with variable success in the maritime climate of Denmark.
During the initial, extended -4°C incubation, a single freezing event occurred within the buds, enabling cryodehydra¬tion.
Bulk tissue water loss also occurred.
During subsequent cooling to -30°C, and then -196°C (liquid nitrogen) no further freezing events or water losses were detected.
The cellular water loss and redistribution that occurs at -4°C is essential for post-thaw survival.
Intercellular and inter-tissue diffusion distances are likely to influence the critical process of cryodehydration, hence the relationship between bud volume and post-thaw survival was considered.
The observation that in some larger buds, the primary meristem did not survive cryopreservation and recovery was attributable to a secondary bud outgrowth, adding support for this line of enquiry.
Bud volumes were measured for three apple cultivars, exhibiting high, medium and low survival following cryopreservation.
The highest survival of primary bud meristems was associated with smaller bud volumes and for larger buds, secondary growth was responsible for almost two thirds of the recorded survival.
The proportion of unfrozen, grafted control material that displayed secondary bud outgrowth did not exceed a quarter.

XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): III International Symposium on Plant Genetic Resources

C. Vogiatzi, B.W.W. Grout, T.B. Toldam-Andersen , D. Wulfsohn

Malus ×domestica, cryopreservation, dormant bud, secondary bud, bud volume, viability

https://doi.org/10.17660/ActaHortic.2011.918.17