A safeguard measure of endemic and endangered plant species: cryostorage of Dianthus taxa

Abstract

The aim of the present study was to determine the optimum parameters for high regrowth following cryostorage (− 196 °C) of seven endemic and endangered Dianthus species. A cryopreservation approach based on a droplet-vitrification protocol was successfully applied using explants (shoot apices and axillary buds) from a collection of in vitro grown Dianthus species. The plants were micropropagated for two years prior using them as explant donors. Osmoprotection in different sucrose concentrations and various dehydration durations in the plant vitrification solution (PVS2) were tested to assess survival and regrowth following cryostorage. The regrowth rates after cryostorage ranged between 63% (D. glacialis ssp. gelidus) and 73% (D. nardiformis) and were achieved after osmoprotection in 0.5 M sucrose and 30 min dehydration in PVS2 for D. glacialis ssp. gelidus and osmoprotection in 0.25 M sucrose and 30 min dehydration in PVS2 for D. nardiformis. The morphogenetic response to liquid nitrogen storage was direct multiple shoot formation for both non-cryopreserved and cryopreserved explants for all species. This biotechnological approach can be efficiently applied for the ex situ conservation of endemic and endangered Dianthus species to ensure the long-term conservation of biodiversity.