AUTHOR=Fernández Ana , León-Lobos Pedro , Contreras Samuel , Ovalle Juan F. , Sershen  , van der Walt Karin , Ballesteros Daniel 

TITLE=The potential impacts of climate change on ex situ conservation options for recalcitrant-seeded species

JOURNAL=Frontiers in Forests and Global Change

VOLUME=Volume 6 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/forests-and-global-change/articles/10.3389/ffgc.2023.1110431

DOI=10.3389/ffgc.2023.1110431

ISSN=2624-893X

ABSTRACT=Recalcitrant seeds are characterized by desiccation and freezing sensitivity, and short storage longevity. These attributes obviate their ex situ conservation in conventional seed banks, where seeds are stored dry at sub-zero temperatures for the long-term. Propagation of plants for field collections (botanical gardens, nurseries, and arboretums) is a valuable ex situ conservation option. However, these collections are relatively costly, require high maintenance, preserve limited genetic diversity and/or are directly exposed to biotic (e.g., pests) and abiotic (e.g., climatic) threats. Therefore, recalcitrant-seeded (RS) species depend on cryopreservation for their safe and long-term ex situ conservation. Different explant sources (whole seeds, zygotic embryos, dormant buds, shoot tips and pollen) can be used for plant propagation of RS species in field collections as well as for their cryopreservation. The success of the propagation or cryopreservation of these explants often depends on their developmental status, vigor, and/or tolerance to desiccation and chilling/freezing. These attributes are modulated by the environment where the donor plant grows and we hypothesize that climate change, by affecting these biological attributes, would impact the success of explant propagation and cryopreservation. To support this hypothesis we have reviewed how temperature changes and drought, the two main climate change scenarios, affect the main biological attributes that are directly involved in the success of ex situ conservation of tropical and temperate RS species.  In general, increases in temperature and drought will negatively affect plant development in field collections and the quality of the explants used in cryopreservation. Consequently, field collections of RS species may need to be moved to more suitable places (higher latitudes/altitudes). Additionally, we may find reduced success in the cryopreservation of germplasm directly harvested from the field. However, we cannot generalize these effects for all species since they often depend on the origin of the species (e.g., tropical and temperate species tend to respond to climate change differently). Conversely, the increase in temperatures and water stress in donor plants at high-latitude areas and some tropical environments may favor the production of seeds/seedlings better adapted to drying, and hence increase the success of plant propagation and zygotic embryo cryopreservation.