Articles
Cryopreservation as a tool for long-term storage of Cohniella cepula (Orchidaceae) seeds
Article number
1297_16
Pages
113 – 120
Language
English
Abstract
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 behavior 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 -196°C 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°C showed high germinability (>90%) even 36 months after collection, revealing no significant differences with fresh seeds.
For seeds stored at -20°C, germination ability remained high (>65%) until 12 months, but it markedly decreased to ~20% after 18 months and fell to 0% after 24 months.
When they were stored at +27 and +4°C, 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.
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 behavior 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 -196°C 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°C showed high germinability (>90%) even 36 months after collection, revealing no significant differences with fresh seeds.
For seeds stored at -20°C, germination ability remained high (>65%) until 12 months, but it markedly decreased to ~20% after 18 months and fell to 0% after 24 months.
When they were stored at +27 and +4°C, 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.
Authors
N.R. Dolce, M.T. González-Arnao
Keywords
ex situ conservation, seed banks, moisture content, asymbiotic germination, orchids
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