Comparative Seed Cryopreservation of Indonesian and New Zealand Epiphytic And Terrestrial Orchids.

The atypical seed storage behaviour reported in several orchid species justifies cryopreservation as a complementary conservation strategy to conventional seed banking. This study aimed to assess the seed cryopreservation potential of five orchid species; tropical epiphytic, Indonesian species (Dendrobium strebloceras, D. lineale), one temperate New Zealand species (D. cunninghamii) and two temperate terrestrial, New Zealand species banksii, Thelymitra nervosa). Seeds were cryopreserved direct immersion in liquid nitrogen (LN) and through the application of a cryoprotectant method. For the latter, seeds were exposed to Plant Vitrification Solution 2 (PVS2) for 0, 50, and 70 min, at either room temperature or on ice, prior to immersion in LN. Seeds all the studied species germinated well following direct cooling in LN. There was no difference in seedling development capability between cryopreserved and non-cryopreserved seeds of both epiphytic species and direct immersion in LN enhanced seed germination and shoot formation both temperate terrestrials. Through a range of analyses of germination and post-growth, our study shows the potential for cryopreserving epiphytic or terrestrial orchids tropical and temperate regions.