Desiccation and freezing studies of dormant buds from selected horticultural woody plant species

Authors: Jenderek, Maria; Postman, Joseph; Stover, Eddie; Ellis, David

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/16/2009
Publication Date: 4/20/2009
Citation: Jenderek, M.M., J.D. Postman, E.W. Stover and D.D. Ellis. 2009. Desiccation and freezing studies of dormant buds from selected horticultural woody plant species. I International Symposium on Cryopreservation in Horticultural Species, April 5-8, 2009. Leuven, Belgium. pp. 91. Meeting abstract.

Interpretive Summary: Several reports have demonstrated the advantages of backing up field maintained collections in liquid nitrogen; however the application of cryopreservation protocols to a wide range of genetic diversity found in germplasm collections has only been reported in a few instances. Long-term preservation of dormant buds is less expensive than cryopreservation of shoot or meristem cultures; hence it presents an option for a back up of woody plant species. Dormant bud cryopreservation procedures can be species dependent but in general they require an ability of the buds to survive desiccation to <30% MC and slow-cooling (1oC/hour) to -35oC prior to liquid nitrogen. Therefore, we looked at survival after desiccation and slow cooling, to assess pre-liquid nitrogen survival of dormant buds from a number of species. Dormant branches were collected from field-grown trees, cut into 35 mm sections containing one dormant bud per section and desiccated to 25-30% MC with or without slow-cooling to -35oC. Bud sections were then rehydrated in moist peat moss and survival was evaluated by grafting. Data indicated that 65-100% of almond and apricot, >80% of sweet cherry, >21% of walnut and >12% of blueberry dormant buds survived desiccation and slow-cooling. In contrast, pomegranate dormant buds did not survive desiccation suggesting other preservation methods may be more applicable for this species. Dormant buds present a difficult experimental system due to many sources of variation which can confound results including the level of dormancy of the buds and the grafting step where success can depend on the personnel doing the grafting as well as the source and variety of the rootstock. Development of dependable cryopreservation protocols would increase the number of woody plant accessions being backed up at the National Center in a considerable shorter time than preserving the accessions via tissue culture material.

Technical Abstract: Several reports have demonstrated the advantages of backing up field maintained collections in liquid nitrogen; however the application of cryopreservation protocols to a wide range of genetic diversity found in germplasm collections has only been reported in a few instances. Long-term preservation of dormant buds is less expensive than cryopreservation of shoot or meristem cultures; hence it presents an option for a back up of woody plant species. Dormant bud cryopreservation procedures can be species dependent but in general they require an ability of the buds to survive desiccation to <30% MC and slow-cooling (1oC/hour) to -35oC prior to liquid nitrogen. Therefore, we looked at survival after desiccation and slow cooling, to assess pre-liquid nitrogen survival of dormant buds from a number of species. Dormant branches were collected from field-grown trees, cut into 35 mm sections containing one dormant bud per section and desiccated to 25-30% MC with or without slow-cooling to -35oC. Bud sections were then rehydrated in moist peat moss and survival was evaluated by grafting. Data indicated that 65-100% of almond and apricot, >80% of sweet cherry, >21% of walnut and >12% of blueberry dormant buds survived desiccation and slow-cooling. In contrast, pomegranate dormant buds did not survive desiccation suggesting other preservation methods may be more applicable for this species. Dormant buds present a difficult experimental system due to many sources of variation which can confound results including the level of dormancy of the buds and the grafting step where success can depend on the personnel doing the grafting as well as the source and variety of the rootstock. Development of dependable cryopreservation protocols would increase the number of woody plant accessions being backed up at the National Center in a considerable shorter time than preserving the accessions via tissue culture material.