CREW’s Ex Situ Plant Collections

The CREW Plant Research Division maintains two ex-situ collections: the In Vitro Collection [I’d like to eventually link to a page on the IVC] and the Frozen Garden® in CREW’s CryoBioBank. The In Vitro Collection consists of plants being grown in vitro, or in plant tissue culture, while the Frozen Garden consists of seeds and tissues of plants in long-term storage in liquid nitrogen.  The In Vitro Collection is used for propagating plants for restoration projects and research, while the Frozen Garden’s purpose is to provide long-term storage of valuable, rare plant tissues as a back-up to threatened populations in the wild.  Such materials might be regrown into plants in order to restore lost populations in the future.

The CREW Plant Division focuses on Threatened Exceptional Plants (TEPs) or those threatened plant species for which seed banking is not an option for long-term ex situ conservation.  Ex-situ conservation is the conservation of plants away from their native habitats.  It includes growing plants in places like botanical gardens as living collections or conserving the species as seeds in a seed bank. Seed banking is a very effective and efficient method for preserving plant genetic diversity for long periods of time in a small space. However, not all species are adapted to the methods required for current conventional seed banking.

When seeds are banked, they first must be dried to a very low moisture level (something most seeds are adapted to doing in nature), and then the dried seeds are put into a freezer and kept at -20oC (-4oF), where they will last for many years.  An example of large seed banks of wild plant species is the Millennium Seed Bank Partnership in England, the European Native Seed Conservation Network (ENSCONET), the Center for Plant Conservation network in the United States, the National Seed Bank Partnership in Australia, and the Germplasm Bank of Wild Species in China.

Exceptional species, however, are plants that will not survive the conditions of seed banking, are short-lived in seed banks, or they have no seeds available to the bank.  Fortunately, there are other methods that can be used to preserve exceptional species, including cryobiotechnology, which combines the methods of cryopreservation with in vitro biotechnologies.  These methods are used in the CREW Plant Division to propagate TEPs and store them long term at -196oC (-321oF) in liquid nitrogen in CREW’s CryoBioBank.


To learn more about exceptional plants, see our Exceptional Plant Conservation Network page.

Crew Plant Lab

To learn more about some of the species the CREW Plant Lab is working, expand one of links below.

Autumn Buttercup (Ranunculus aestivalis)

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Methods for propagating Autumn Buttercup, known from only one area in Utah, have been developed, using tissue cultures started from seedlings.  Plants produced in this project have been used to augment a declining population of this species in Utah.

The autumn buttercup was put on the federal List of Endangered and Threatened species, and two public gardens, the Center for Conservation and Research of Endangered Wildlife (CREW) at the Cincinnati Zoo &  Botanical Garden and The Arboretum at Flagstaff; the US Fish & Wildlife Service; and Weber State University teamed up with The Nature Conservancy to restore the buttercup in its native habitat. Read more about CREW’s work with the Autumn Buttercup here.

Click here to read more about the 2017 Autumn Buttercup project via WCPO
Cumberland Sandwort  (Arenaria cumberlandensis)

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Cumberland Sandwort plants have been propagated using tissue culture, and these methods have been used to produce plants that have been outplanted in the Daniel Boone National Forest.  This experimental population has demonstrated that Cumberland Sandwort plants produced through tissue culture can be used to produce a viable population in the wild.  Tissues have also been banked in CREW’s Frozen Garden.

Northern Wild Monkshood  (Aconitum noveboracense)

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Shoot tips collected from wild plants in Akron, OH, were used to initiate plant tissue culture lines of Northern Wild Monkshood.  This population has been particularly vulnerable to salt run-off from a nearby road and an invasive species.  Tissue culture-propagated plants were produced in the Plant Research Division of CREW and were given to collaborators at Gorge Metro Parks to augment their population at risk.

Avon Park Harebells (Crotalaria avonensis)

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Avon Park harebells is a small legume (Fabaceae family) that is known from only three populations in south-central Florida.  It is specifically adapted to the sandy scrub habitat of the Lake Wales Ridge, an area that is home to a variety of unique plants and animals.  Because this land is desirable for development and agriculture, much of the original habitat has been lost. Of the three known populations of the Avon Park harebells, two are protected and one is not.

The unprotected population is in the city of Avon Park, in undeveloped housing lots.  CREW has collaborated with researchers at Archbold Biological Station (ABS), located near Lake Placid, FL, who has studied and monitored this species for a number of years.  CREW’s Plant Division has developed in vitro (tissue culture) propagation methods for this species and has used those methods to propagate plants from the unprotected population.  Young partially acclimatized plants were sent to collaborators at Bok Tower Gardens in Lake Wales, FL, for further acclimatization to the Florida climate.

In August 2012, 84 plants propagated by CREW and Bok Tower Gardens were planted by ABS researchers at a protected site.   All of the plants died back, but as of March 2013, a number of the plants were starting to regrow.

This is encouraging, indicating that the methods used for propagation, including in vitro methods, produced plants that are adapting to the new location, and that these methods could be used to produce further plants for restoration.  CREW researchers are also working to cryopreserve tissues of this species, for long-term storage in CREW’s CryoBioBank.

This collaboration in restoration, between the CREW Plant Division, Bok Tower Gardens, and Archbold Biological Station, with funding from the U.S. Fish & Wildlife Service, is helping to bring the unprotected genotypes of the Avon Park harebells into a secure future.

The original work in developing in vitro propagation and cryopreservation protocols for this species was supported in part by grants from the Institute of Museum and Library Services.

Avon Park harebells, flowering in Florida
Avon Park harebells, flowering in Florida
Avon Park harebells habitat in Florida
Avon Park harebells habitat in Florida
Tissue culture propagated shoot with roots, at CREW
Tissue culture propagated shoot with roots, at CREW
Tissue culture propagated plant acclimatized to soil at CREW
Tissue culture propagated plant acclimatized to soil at CREW
Outplanting propagated plants into a secure site.
Outplanting propagated plants into a secure site.
More about Florida Rare Species

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Roughly one-quarter of all the species targeted in the Threatened Plant Propagation Program are from Florida.  Collaborators at Historic Bok Sanctuary, Fairchild Tropical Botanical Garden, and the Marie Selby Botanical Garden work with CREW to identify species for which propagation at CREW could make a difference in the long-range conservation of the species.  Targeted species focus on threatened species from scrub and pine rockland/hardwood hammock habitats and include a variety of woody species,  perennials, orchids, and ferns.

To learn more about other areas of CREW’s plant research:
  • The Local Flora Project’s goal is to understand how changes in our region over the past 200 years have affected local flora.
  • CryoBioBank® is a cryostorage facility for long-term germplasm storage of seeds and tissues of threatened plants.
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