Cryopreservation of Ammodendron persicum (Bunge ex Boiss.) Seeds and Evaluation of the Cryogenic Seeds under Various Conditions

Ammodendron persicum (Bunge & Boiss.)is a desert shrub specie which grows on some sand dunes and sandy areas of South Khorasan and Sistan-va-Baluchestan provinces in east of Iran. Low distribution and narrow ecological range have put this species under threat. In order to evaluate the possibility of long-term preservation of A. persicum seeds in cryogenic conditions (-196°C), the seeds of species were collected from its natural habitats and three pre-cryopreservation treatments including PVS2, Desiccation, and 30% Glycerol as well as non-treated (Control) were applied before transferring the seeds into Liquid Nitrogen (LN) or at -196°C. The treated seeds were incubated in LN for a period of 1 week. Subsequently, the cryopreserved seeds were removed from the LN and subjected to post-cryopreservation treatment. Seed germination and establishment were evaluated under laboratory, greenhouse and natural conditions. The laboratory results showed that seeds of the A. persicum species can tolerate cryogenic conditions. The effects of the pre-cryopreservation treatments including Desiccation, 30% Glycerol, and PVS2, and non-treated (Control) one on germination of cryopreserved seeds were significantly different. The non-treated (Control) and Desiccation, respectively showed the best effects on the survival rate (51%) and other attributes of the cryopreserved seeds. The results revealed that the cryopreserved seeds were also able to germinate and establish under greenhouse and desert conditions. In this study, the appropriate seeding depth, the seed sowing time and factors affecting the seed germination as well as establishments under natural conditions were evaluated. The results revealed that cryopreservation approach is the most promising method for long-term preservation of the A. persicum seeds. Long-term seed preservation via cryopreservation is an important approach to prevent this species from loss of genetic diversity and risk of extinction