Desiccation, dormancy, and storage of Pterocarya fraxinifolia (Juglandaceae) seeds: application in Hyrcanian and Colchis forest conservation

Pterocarya fraxinifolia (Juglandaceae) is a model relict tree species native to South Caucasus and it is a typical element of threatened riparian forests. Intensive land transformations which is common in Transcaucasia, resulted in loss of natural habitat and population decline of the species. One of the method for ex situ conservation is seed banking. Cryopreservation in liquid nitrogen (LN; -196°C) is particularly of interest as it allows safe preservation of valuable plant genetic resources. However, the feasibility of seed cryopreservation is related to their desiccation tolerance and intrinsic composition. In this study, we examined the physiological P. fraxinifolia seed traits from which desiccation tolerance is unknown or controversial and their feasibility to cryopreservation,. Additionally, we tested stratification methods for dormancy assessment. Results showed that seeds survived desiccation to a 2.8% seed moisture content (MC) and germinated in 64% . Stratification at temperature 3°C for 8 weeks was proven to be both fast and effective. For cryopreservation, seed MC ranging between 2.8% and 18.1% was determined to be safe. There was no difference in seedling emergence in seeds stored for one year regardless of the storage temperature ( 3°, -18° or -196°C). Based on our results, P. fraxinifolia seeds can be classified as orthodox. This study demonstrates for the first time the feasibility of cryopreserving P. fraxinifolia seeds.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author