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

Abstract

Background: The atypical seed storage behaviour reported in several orchid species justifies cryopreservation as a complementary conservation strategy to conventional seed banking. Objective 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). MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.