Abstract
Elms are threatened by Dutch elm disease, and conservation methods are needed to protect their genetic diversity. Cryopreservation of dormant buds allows large numbers of genotypes to be conserved with small space requirements and minimal upkeep. Cryopreservation through slow controlled cooling was tested for both elm species native to Finland, Ulmus glabra and Ulmus laevis. Regeneration of the thawed buds by micropropagation was studied on different basal media and using different growth regulators. Multiple surface sterilisation methods were tried out for bud explants. The multiplication of U. glabra was investigated with Driver and Kuniyuki walnut medium with either 0.5 mg/L meta-topolin or 0.5 mg/L 6-benzylaminopurine. Rooting with short indole-6-butyric acid induction in liquid medium and direct transplantation of the shoots to peat ex vitro after induction were tested. For initiation, either Murashige and Skoog or Driver and Kuniyuki walnut medium with 0.02 mg/L gibberellic acid 4 + 7 and 0.5 mg/L 6-benzylaminopurine were found to best promote shoot formation. Surface sterilisation remains the most challenging step. No significant differences were found between the multiplication media in either shoot production or rooting success. Rooting by direct transplanting was achieved in both species, but further development is required before application on a larger scale. With further improvements to sterilisation success especially in U. glabra, the method can be applied to the conservation of genetic resources of both U. laevis and U. glabra, and knowledge of regeneration success can be used to design the cryoconservation plan and optimise the sampling.
Highlights
Elms are deciduous trees valued in silviculture and urban landscaping due to their unique appearance and adaptability to city conditions [1]
U. laevis both fresh and cryopreserved dormant buds. This is consistent with results from other from both fresh and cryopreserved dormant buds. This is consistent with results from deciduous trees, e.g., Betula pendula Roth [22] and hybrid aspen Populus tremula L.× Populus other deciduous trees, e.g., Betula pendula Roth [22] and hybrid aspen Populus tremula L.×
The micropropagation protocol works for both U. laevis and U. glabra, and the regeneration of most U. laevis genotypes from cryostorage is successful
Summary
Elms are deciduous trees valued in silviculture and urban landscaping due to their unique appearance and adaptability to city conditions [1]. The populations are mainly located in Southern Finland, separated from each other and too small to allow effective in situ conservation [4]. The genetic resources of the two species are being conserved in outdoor ex situ collections bringing together elms from multiple populations to produce seed with higher genetic diversity than natural populations. In addition to habitat loss due to agriculture, logging and water regulation [3,4], elms are globally threatened by Dutch elm disease (DED), which is considered one of the most devastating known plant diseases [5]. The first DED pandemic occurred around 1910 when the fungal pathogen Ophiostoma ulmi Buisman spread throughout Europe, and later with infested timber imports into
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
