Exceptional Species

Dr. Valerie Pence, Cincinnati Zoo & Botanical Garden

Although there are published protocols for initiating shoot cultures for over 20 oak species, the cryopreservation of oak shoot tips has not been reported. We have applied the droplet vitrification protocol to four species of oaks, including the endangered Q. hinckleyi, in order to evaluate the feasibility of using shoot tip cryopreservation for oak ex situ conservation. Good survival through liquid nitrogen exposure was achieved for Q. virginiana, low survival for Q. hinckley and Q. suber, and no survival for Q. gambelii. Survival of Q. virginiana shoot tips was enhanced further by preculturing and recovering using an alternating temperature culture regime (25oC, 16 hr light/15oC, 8 hr dark). These results suggest that one procedure will not be ideal for all oak species, but that changes to the growth conditions can positively influence survival. Future studies will apply changes that were successful with Q. virginiana to oak species with lower levels of survival and other modifications will be made to work to improve survival for the other three species tested here, as well as for additional species in the CREW collection.

Contributing Author(s): 
Date Recorded: 
Friday, October 9, 2020

Zoe Diaz-Martin, Chicago Botanic Garden

As global biodiversity continues to decline, how can we ensure the long-term conservation of exceptional plant species? Our collaborative project is addressing this question by developing tools and resources that will position botanic gardens as key players in global plant conservation. In adopting the successful framework used in the zoological community, we will provide the digital infrastructure needed to cooperatively manage and breed exceptional plant species across botanic garden collections with the goal of maximizing the genetic diversity of these populations and enhancing their capacity for reintroduction efforts. More specifically, we are working with BGCI to update PlantSearch to host accession data and with Zoological experts to modify the software used to manage captive animal populations. This presentation will review the approach and tools we are developing and provide results from a pilot species, Brighamia insiginis, a Hawaiian endemic.

Date Recorded: 
Friday, October 9, 2020

Amy Byrne, The Morton Arboretum

A 2019 study by Griffith, et al. showed that gardens must collaborate to conserve genetic diversity, especially for exceptional species whose seeds cannot be conventionally seed banked. This process of capturing the genetic diversity of exceptional species in ex situ collections requires a tailored strategy for each species, emphasizing the need for a coordinated effort by botanic gardens. By working through networked consortia, botanic gardens can implement innovative solutions to safeguard these species in a changing world, in high conservation value “metacollections”. We highlight a new initiative to conserve genetic diversity of exceptional species through a coordinated effort of gardens, using the metacollection model: the Global Conservation Consortium for Oak (GCCO). We outline the challenges and provide solutions for conserving this iconic group of exceptional trees, and provide recommendations that can guide conservation efforts for other exceptional plant groups, especially large, long-lived trees. With our many CPC partners, we are working to grow a diverse, coordinated network of institutions and experts who will advance our goal in preventing the extinction of the world’s exceptional species.

Contributing Author(s): 
Date Recorded: 
Friday, October 9, 2020

Joyce Maschinski, Center for Plant Conservation

Joyce Maschinski interviews world famous plant cryo-biologists to learn about how cryopreservation is imperative for the future of food. Many food crops can't be preserved using traditional seed preservation methods. For some of these species cryopreservation is the only long term option. Plant researchers from across the globe are working to develop and perfect these cryo-technologies in order to conserve these exceptional species for future generations.

Contributing Author(s): 
Date Recorded: 
Wednesday, October 7, 2020

Christina Carrero, The Morton Arboretum, Emily Coffey, Atlanta Botanical Garden, Patrick Griffith, Montgomery Botanical Center

A 2019 study by Griffith, et al. showed that gardens must collaborate to conserve genetic diversity, especially for exceptional species whose seeds cannot be properly seed banked. This process of capturing the genetic diversity of exceptional species in ex situ collections requires a tailored strategy for each species, emphasizing the need for a coordinated effort by botanic gardens. By working through networked consortia, botanic gardens can implement innovative solutions to safeguard these species in a changing world. We highlight a new initiative to conserve genetic diversity of exceptional species through a coordinated effort of gardens, using oak, magnolia, maple, and cycad consortia as case-studies. We outline the challenges and opportunities of conserving exceptional species within these distinct plant groups, providing solutions and recommendations that can guide collection efforts for other groups.The audience will gain a better understanding of exceptional plant species, conservation challenges, and innovative solutions. Participants will be provided with the tools and framework to join or create a consortium as a way to contribute to the conservation efforts of threatened exceptional plants. Our hope is that these presentations will gain new consortium members, growing a diverse, coordinated network of institutions and experts who will advance our goal in preventing the extinction of the world’s exceptional species. Ultimately, by working through networked consortia, the sum of our efforts is greater than its parts.

Contributing Author(s): 
Date Recorded: 
Wednesday, March 4, 2020

Megan Philpott, Valerie PenceL*, Cincinnati Zoo & Botanical Garden, United States *Speaker

Threats to global plant biodiversity compel the need for ex situ collections of species worldwide. However, the subset of species known as exceptional plants are often overlooked. These species produce few or no seeds or produce recalcitrant seeds. The Center for Conservation and Research of Endangered Wildlife (CREW) at the Cincinnati Zoo & Botanical Garden maintains a liquid nitrogen bank of exceptional plant seeds and tissues known as the CryoBioBank®. CREW has partnered with the Lyon Arboretum in Honolulu to develop cryopreservation protocols for 21 endangered exceptional Hawaiian plant species and bank them in the CryoBioBank®. To date, micropropagation protocols to produce target tissues have been tested in 13 species, and cryopreservation protocols have been tested in 7 species. As an example, in Cyrtandra gracilis, micropropagation on medium containing 2mg/L of the auxin indole-3-acetic acid and 0.1mg/L of the cytokinin 6-benzylaminopurine induces shoot organogenesis on excised leaves. These leaves were dissected into leaf bud segments and compared with shoot tips for survival after liquid nitrogen storage. Cryopreservation of shoot tips using droplet vitrification (DV) with PVS2 yielded 0% survival, while leaf bud segments yielded 20% survival. DV using PVS3 increased survival in these leaf buds to 60%. Cryopreservation of leaf bud segments immediately after bud primordia formed yielded 25% survival compared to 50% survival if the buds were left to develop into shoots before cryopreservation. Shoot tips from another species, Melicope mucronulata, have been banked in the CryoBioBank® using the DV method following an experimental survival rate of 57% after 2 days of pre- culture on a 0.3M mannitol medium instead of one day on 0.3M mannitol and one day on 0.5M mannitol medium. This project will result in the long-term protection of many endangered exceptional Hawaiian species that would otherwise be unbankable using conventional methods. (Supported by IMLS grant #MG-30-17-0055-17).

Contributing Author(s): 
Date Recorded: 
Thursday, July 25, 2019

Jeremie Fant, Chicago Botanic Garden

This talk highlights the Chicago Botanic Garden’s work on adapting zoo conservation approaches for exceptional plant species. Challenges in ex situ conservation include genetic issues that arise from limited numbers of individuals and founders, and husbandry and hybridization issues encountered during the growing out of collections. A significant advantage in plant conservation is that seeds can be collected for a vast majority of plants. One example is the CBG's Dixon Tallgrass Prairie Seedbank, which has more than 1,700 species and 10,000 accessions. 

Although banking options are more restricted in animal conservation, other approaches used by the zoo community can be adapted to improve success rates in ex situ plant conservation programs. One such approach is pedigree analysis, which shifts focus from high numbers of individuals to equal numbers of founders. The CBG is testing pedigree analysis on several species, as illustrated by work done with Brighamia insignis. The steps include tracking founders by creating a pedigree of collections, calculating relatedness between all individuals, and making management decisions. This method enables researchers to identify genetically valuable individuals across collections, use life span of a species in collections to determine the sample size needed to maintain a collection, and identify crosses needed to increase diversity and improve collection robustness.

One of the next steps planned by the CBG is to identify collection plants less valuable for maintaining genetic diversity, and use them to test restoration techniques. The ultimate goal is to use ex situ collections for restoration of rare species in the field.

Contributing Author(s): 
Date Recorded: 
Thursday, May 2, 2019

What is the standard for determination of Exceptional Species status?

Is it only species that have seeds that exhibit no viability in both desiccation and cold? Or is it a lower bar of reduced viability in both, and if so, how reduced?

Question Category: 

Joyce Maschinski, Center for Plant Conservation and Valerie Pence, Cincinnati Zoo & Botanical Garden

Crotalaria avonensis is an endangered legume endemic to Florida that produces few seeds. In vitro shoot cultures of multiple genotypes have been grown at CREW to provide genetic diversity for restoration and for tissue cryopreservation. These cultures harbor a bacterium, identified as Paenibacillus sp., which may be a natural endophyte in the species. The bacterium grows slowly and does not appear to inhibit the in vitro propagation of the species, but its effect on the recovery of shoot tips after the stress of cryopreservation was investigated. Samples banked using encapsulation vitrification and representing 63 genotypes were evaluated after 4 - 15 years in liquid nitrogen. The rate of recovery growth of samples with visible bacteria was significantly less than samples without bacteria. Similarly, when newly banked shoot tips of 15 genotypes were cryopreserved using an improved technique, droplet vitrification, and were recovered, the presence of antibiotic in the medium significantly increased the percent of shoot tips showing recovery growth. Whereas C. avonensis shoots can be propagated, rooted, and acclimatized in the presence of this bacterium, recovery after the stress of cryopreservation is reduced when the bacteria are present. An increasing number of plant species are being shown to have endophytes in the wild and removing such endophytes may not be possible or desirable in culture. These results with C. avonensis demonstrate the potential for controlling the negative effects of such microorganisms in vitro. This is one example of the particular challenges that may be presented in working with wild species and conserving endangered exceptional plants. Supported in part by grants from the Institute of Museum and Library Services.

Contributing Author(s): 
Date Recorded: 
Friday, May 4, 2018

Although many rare plants have seeds that can be stored by conventional methods, not all species have seeds that can live after drying or freezing. Sometimes called "Exceptional plants, " these species have a wide range of variation. Some produce few or no seeds, thus they cannot be seed banked, others have seeds or spores that will die if dried or frozen, while others have seeds that can tolerate drying, but not freezing, and another group have seeds that live less than 10 years at freezing temperatures. Recent studies suggest that there are many rare plant species that need alternative storage for conservation. This video describes a procedure for  testing whether rare plants can be stored in liquid nitrogen successfully.

Date Recorded: 
Friday, March 1, 2019