Cryopreservation as a tool for long-term storage of Cohniella cepula (Orchidaceae) seeds

GONZÁLEZ ARNAO, MARÍA T.; DOLCE, NATALIA R.

Estambul

Congreso; XXX International Horticultural Congress; 2018

International Society for Horticultural Science

Cohniella cepula (Orchidaceae) is a wild species of Argentina, Bolivia, Brazil, Paraguay, and Peru with great ornamental potential, which is threatened because of the extensive disturbance of their natural habitat and indiscriminate harvesting of naturally growing plants. Consequently, it is imperative to develop effective preservation strategies for this orchid species. Seed storage has particular application for germplasm conservation of wild endangered and rare species since it allows conservation of diverse genotypes, besides the small storage space requirements due to minute seed size. In this study, we examined the storage behaviour of C. cepula seeds at different temperatures. Green fruits containing mature seeds were collected at 85, 90 and 95 days after hand-pollination. Fruits were surface sterilized, opened in a laminar flow hood and then seed samples were removed and stored at +27, +4, -20, and -196ºC up to 36 months. Moisture content (MC) and in vitro germination were determined for fresh seeds from each fruits. Seeds from 85 to 95 day-old fruits (5-11% MC) stored at -196 ºC showed high germinability (>90 %) even 36 months after collection, revealing no significant differences with fresh seeds. For seeds stored at -20ºC, germinability remained high (>65%) after 12 months, but it markedly decreased to ~20% after 18 months and fell to 0% on 24 months after storage. When they were stored at +27 and +4ºC, seed germination rapidly decreased to 0% within 1-6 months storage. Thus, long-term storage of C. cepula seeds is feasible through cryopreservation by immersing seeds in liquid nitrogen without any previous treatment.