Cryopreservation of Ulmus glabra Hudson seeds

Wych elm (Ulmus glabra Hudson) is one of the forest species in Hyrcanian forests of Iran and considered as threatened species due to its narrow ecological range, over-exploitation, as well as Dutch elm disease. In order to evaluate the possibility of cryopreservation of Ulmus glabra seeds for long-term preservation, seeds were collected from natural habitats and three pre-treatment methods including PVS2, Desiccation, and 30% Glycerol were applied before incubating the seeds in liquid nitrogen (-196°C). The treated seeds were incubated in liquid nitrogen (LN) for periods of 0 week (without exposure to LN), 1 week, 1 month, and 1 year. After removing the cryopreserved seeds from LN, seed germination, seed vigor, and other attributes were evaluated under laboratory conditions. Furthermore, seedling establishment was assessed under greenhouse conditions. Desiccation had the best effects on survival rate and other attributes of the cryopreserved seeds. However, PVS2 and 30% Glycerol had negative effect on all the attributes. The seeds of Ulmus glabra are able to tolerate cryogenic conditions and cryopreserved seeds are able to grow into normal plants. Seeds of the species can be collected from different areas and preserved for long periods using desiccation pre-treatment method before incubation in LN.