Seed desiccation tolerance and dormancy of three endangered New Zealand species: Carmichaelia williamsii, Clianthus puniceus and Hibiscus diversifolius

At least one third of New Zealand's indigenous plant species are threatened with extinction and strategies for conserving endangered flora are urgently required. One strategy is to use ex situ seed storage as a complement to in situ conservation. Successful ex situ storage of seed requires knowledge of the seed storage behaviour, optimal storage conditions and germination requirements of the species being stored. For many threatened species, however, this information is either incomplete or unavailable. In this study, preliminary experiments were conducted with three threatened species, Carmichaelia williamsii, Clianthus puniceus and Hibiscus diversifolius, to determine their desiccation tolerance and dormancy status. Seeds were tested for germination following desiccation and dormancy-breaking treatment. Seeds of all three species could be dried to moisture contents of 2.9-3.7% without losing viability. All three species became predominantly hardseeded at approximately 10% moisture content. However, C. puniceus became permeable to water again at moisture contents below 6%. In all species, manual scarification of seeds improved germination to 96-100% compared with 5-20% in untreated seeds. Dormancy in these species is a function of the seed coat preventing water uptake by the dry seed. While seeds of these species are most likely desiccation tolerant and thus can potentially be stored for long periods under conventional conditions, the loss of dormancy of C. puniceus at very low moisture contents is of concern. More work is needed to confirm the long-term storage behaviour of these species. Keywords: ex situ conservation, seed storage behaviour, New Zealand flora

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High seed viability recorded in an endangered endemic species, 'Isoplexis isabelliana' (Scrophulariaceae), after more than 30 years of storage in a conservation seed bank

Mediterranean Botany ◽

10.5209/mbot.69341 ◽

2021 ◽

Vol 42 ◽

pp. e69341

Author(s):

Miguel Ángel González Pérez ◽

Nereida Cabrera-García ◽

Isabel Cayon-Fernández

Keyword(s):

Seed Bank ◽

Germination Rate ◽

Genetic Material ◽

Natural Populations ◽

Seed Viability ◽

Seed Storage ◽

Botanical Garden ◽

Storage Conditions ◽

Seed Banks ◽

Ex Situ

Conservation seed banks are essential for ex-situ conservation of genetic biodiversity. These institutions are especially relevant for threatened species and play a vital role in their conservation by preserving genetic material. However, samples deposited in the seed banks must germinate when necessary to use them (i.e., recovery plans, etc.). This study uses four accessions of the endemic endangered species from Gran Canaria Island (Canary Islands), Isoplexis isabelliana (Webb & Berthel.) Masf. (Scrophulariaceae). Germination tests were carried out to measure seed viability through time and the possible impact of seed storage on their viability. These accessions have been kept in the seed bank for four months to thirty years under different storage conditions. Germination results differed for seeds after 45 days of exposition using 16 hours light and 8 hours darkness at 17 °C. Accessions kept in the seed bank, independently of storage, showed a high germination percentage (89%). Whereas the accessions with rough storage conditions showed a 0% germination rate. The results highlighted the good state of conservation of the material deposited in the Seed Bank of the Botanical Garden "Viera y Clavijo" and the reliability of the temperature and humidity conditions in which the seeds of I. isabelliana have been stored. We consider these results as momentous since several natural populations of I. isabelliana has been affected by the last forest fire on the island.

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Optimal long-term seed storage conditions for the endangered seagrass Zostera japonica: implications for habitat conservation and restoration

Plant Methods ◽

10.1186/s13007-019-0541-6 ◽

2019 ◽

Vol 15 (1) ◽

Cited By ~ 1

Author(s):

Shidong Yue ◽

Yu Zhang ◽

Yi Zhou ◽

Shaochun Xu ◽

Shuai Xu ◽

...

Keyword(s):

Seed Storage ◽

Storage Conditions ◽

Seed Vigor ◽

Ex Situ ◽

Zostera Japonica ◽

Storage Method ◽

Seagrass Meadows ◽

Long Term Storage ◽

Term Storage

Abstract Background Seagrass meadows are recognized as critical and among the most vulnerable habitats on the planet. The alarming rates of decline in seagrass meadows have attracted the attention globally. There is an urgent need to develop techniques to restore and preserve these vital coastal ecosystems. So far little work has been done to develop effective long-term storage method for seagrass seeds. The seagrass Zostera japonica Asch. & Graebn is an endangered species in its native range. Here we utilized combinations of different storage times, salinities, and temperature to determine the most appropriate conditions for optimal seed storage. Results Zostera japonica seeds were strongly desiccation sensitive, with a complete loss of viability after 24 h of desiccation. Therefore, long periods of exposure to air should be avoided to minimize seed mortality. In addition, Z. japonica seeds could not endure freezing conditions such as – 5 °C. However, our results indicated that reduced storage temperature to 0 °C could effectively prolong the duration of dormancy of Z. japonica seeds. Seeds stored at 0 °C under a salinity of 40–60 psu showed relatively low seed loss, high seed vigor and fast seed germination, suggesting these to be optimal seed storage conditions. For example, after storage for 540 days (ca. 600 days since the seed collection from reproductive shoots in early October, 2016) at 0 °C under a salinity of 50 psu, seeds still had a considerable vigor, i.e. 57.8 ± 16.8%. Conclusion Our experiments demonstrated that seeds stored at 0 °C under a salinity of 40–60 psu could effectively prolong the duration of dormancy of Z. japonica seeds. The proposed technique is a simple and effective long-term storage method for Z. japonica seeds, which can then be used to aid future conservation, restoration and management of these sensitive and ecologically important habitat formers. The findings may also serve as useful reference for seed storage of other threatened seagrass species and facilitate their ex situ conservation and habitat restoration.

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What Do We Know About the Genetic Basis of Seed Desiccation Tolerance and Longevity?

International Journal of Molecular Sciences ◽

10.3390/ijms21103612 ◽

2020 ◽

Vol 21 (10) ◽

pp. 3612

Author(s):

Hanna Kijak ◽

Ewelina Ratajczak

Keyword(s):

Low Temperature ◽

Desiccation Tolerance ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Seed Storage ◽

Water Losses ◽

Economic Interests ◽

Seed Desiccation ◽

Orthodox Seeds ◽

The Right

Long-term seed storage is important for protecting both economic interests and biodiversity. The extraordinary properties of seeds allow us to store them in the right conditions for years. However, not all types of seeds are resilient, and some do not tolerate extreme desiccation or low temperature. Seeds can be divided into three categories: (1) orthodox seeds, which tolerate water losses of up to 7% of their water content and can be stored at low temperature; (2) recalcitrant seeds, which require a humidity of 27%; and (3) intermediate seeds, which lose their viability relatively quickly compared to orthodox seeds. In this article, we discuss the genetic bases for desiccation tolerance and longevity in seeds and the differences in gene expression profiles between the mentioned types of seeds.

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Conservation of threatened plant species in botanic garden reserves in Brazil

Oryx ◽

10.1017/s0030605316000776 ◽

2016 ◽

Vol 52 (1) ◽

pp. 108-115 ◽

Cited By ~ 2

Author(s):

Maria Lúcia M. N. da Costa ◽

Peter Wyse Jackson ◽

Ricardo Avancini Fernandes ◽

Ariane Luna Peixoto

Keyword(s):

Plant Species ◽

Threatened Species ◽

In Situ Conservation ◽

Integrated Approach ◽

Ex Situ ◽

Conservation Strategies ◽

Botanic Gardens ◽

Threatened Plant Species ◽

Integrated Conservation ◽

Scientific Value

AbstractOver the last few decades botanic gardens worldwide have been encouraged to adopt complementary measures for the conservation of plant species from their own regions, combining in situ conservation efforts with ex situ methods, both in cultivation and in storage. This integrated approach is particularly important for botanic gardens in the tropics, which face the challenge of conserving a highly diverse and often threatened flora. We gathered information on the occurrence of threatened species in the natural vegetation reserves of 21 Brazilian botanic gardens. The data were collected from herbarium records in the database of the National Centre for Flora Conservation, and from the available plant inventories of these reserves. The results indicate that 148 species from the List of Threatened Species of Brazilian Flora are recorded as having been collected in the reserves. Of these, 51 species were maintained in the living collections of 18 botanic gardens and 83 species were recorded in federally protected areas. The occurrence of threatened species in the reserves of botanic gardens highlights the scientific value of these areas, as well as their biological, social and cultural importance for conservation. The results may be used to inform the planning of integrated conservation strategies for threatened species.

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Primed Lettuce Seeds Exhibit Increased Sensitivity to Moisture Content During Controlled Deterioration

HortScience ◽

10.21273/hortsci.42.6.1436 ◽

2007 ◽

Vol 42 (6) ◽

pp. 1436-1439 ◽

Cited By ~ 12

Author(s):

H.J. Hill ◽

Jesse D. Cunningham ◽

Kent J. Bradford ◽

A.G. Taylor

Keyword(s):

Moisture Content ◽

Elevated Temperatures ◽

Seed Viability ◽

Seed Storage ◽

Seed Priming ◽

Storage Conditions ◽

Seed Moisture Content ◽

Moisture Contents ◽

Lettuce Seeds ◽

Rate Of Decline

The Ellis-Roberts seed viability equation is used to predict seed survival after storage at specified temperatures and moisture contents. Seed priming, which can break dormancy and accelerate germination, can also reduce seed storage life. Because primed seeds were not used in developing the Ellis-Roberts equation, the reciprocal nature of specific seed moisture content (MC, fresh weight basis) and temperatures that applies to nonprimed lettuce (Lactuca sativa L.) seeds may not apply to primed seeds. To determine how priming affects lettuce seeds in relation to the viability equation, an experiment was conducted using two cultivars, ‘Big Ben’ and ‘Parris Island Cos’. Seeds primed in polyethylene glycol 8000 (–1.45 MPa, 24 h at 15 °C) and nonprimed seeds were first adjusted to 6% and 9% moisture contents and then stored at 48 and 38 °C for up to 30 days, respectively. These storage conditions (6% MC and 48 °C; 9% MC and 38 °C) were predicted by the viability equation to result in equal longevities. Subsequent viability assays at 20 °C revealed that nonprimed seeds in both storage environments exhibited similar losses in viability over time, thus validating the Ellis-Roberts equation and the use of these conditions to apply different but equal aging stress. Primed seeds of both cultivars deteriorated faster than nonprimed seeds as expected. However, primed seeds did exhibit different rates of deterioration between the storage environments. Primed seeds stored at 9% MC and 38 °C deteriorated faster than primed seeds stored at 6% MC and 48 °C. The rate of decline in probit viability percentage was three times greater in primed ‘Big Ben’ seeds stored at 9% MC and 38 °C than for those stored at 6% MC and 48 °C (–1.34 versus –0.26 probits per day, respectively). ‘Parris Island Cos’ seeds stored at 9% MC and 38 °C had twice the rate of deterioration that those stored at 6% MC and 48 °C (–1.19 and –0.49 probits per day, respectively). The results indicate that primed lettuce seeds were more sensitive to the adverse effects of higher seed MC than were nonprimed seeds during storage at elevated temperatures.

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The Restoration of Erica verticillata

Sibbaldia: the International Journal of Botanic Garden Horticulture ◽

10.24823/sibbaldia.2017.222 ◽

2017 ◽

pp. 39-63 ◽

Cited By ~ 1

Author(s):

Anthony Hitchcock ◽

Anthony G. Rebelo

Keyword(s):

Threatened Species ◽

Vegetation Type ◽

In Situ Conservation ◽

Plant Conservation ◽

Global Strategy ◽

Ex Situ ◽

Suitable Habitat ◽

Natural Ecosystem ◽

Restoration Process

The Threatened Species Programme at the South African National Biodiversity Institute, Kirstenbosch National Botanical Garden, is integrated to include both ex situ and in situ conservation activities. Plant conservation is driven by South Africa’s Strategy for Plant Conservation which was developed in response to the Global Strategy for Plant Conservation. This case study examines the conservation of Erica verticillata (whorl heath), a flagship for threatened species at Kirstenbosch, and documents the integration of ex situ with in situ conservation at three areas on the Cape Flats. The whorl heath was thought to be extinct by 1950. Horticulturists have since rediscovered eight clones in botanic gardens worldwide, the Heather Society and commercial growers. Ex situ conservation in botanic garden collections and the Millennium Seed Bank has since allowed in situ conservation in the critically endangered Cape Flats Sand Fynbos vegetation type. The process of restoring the whorl heath presented many challenges. Initially attempts were hampered by limited available knowledge on suitable niche habitats. Pioneering work carried out at Rondevlei Nature Reserve identified the suitable habitat and this was applied in subsequent in situ work at Kenilworth Racecourse Conservation Area and at Tokai Park – the only natural areas remaining in or near this species’ historical distribution range. Successful re-establishment of this species depends upon its capacity to recruit after fire, which is an essential ecological process in the fynbos. Many clones have been in cultivation for a long time and are poor seed producers: seed production was first recorded at Rondevlei only after additional clones were planted together. Only one population (Rondevlei) to date has seen a fire and thus has recruited seedlings; however these are competing with vigorous companion plants. The study continues and is currently exploring the role of herbivory in the restoration process. The key lesson learnt to date is the need to include sustainable management of the entire ecosystem in the restoration process and not limit it to single species. Success in restoring a species depends upon a healthy stand of the vegetation type in place, along with pollinators and other key fauna and other natural ecosystem processes. It is recommended that successful re- establishment of a species in fynbos requires the reintroduced population to survive three fire cycles.

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Seed survival in Chilean Nothofagus in response to desiccation and storage

Seed Science Research ◽

10.1079/ssr2005204 ◽

2005 ◽

Vol 15 (2) ◽

pp. 113-123 ◽

Cited By ~ 4

Author(s):

Pedro León-Lobos ◽

Richard H. Ellis

Keyword(s):

Moisture Content ◽

Seed Quality ◽

Seed Viability ◽

Seed Storage ◽

Forest Tree ◽

Ex Situ ◽

Hermetic Storage ◽

Moisture Contents ◽

Tree Seeds ◽

Initial Seed

Nothofagus alpina,N. obliqua,N. glauca,N. leonii,N. dombeyiandN. pumilioseeds exhibited consistent, albeit slight, sensitivity to extreme desiccation, but nevertheless maintained viability at low moisture contents and cool temperatures (–10° to –20°C) over 2 years.Nothofagus alpina,N. obliqua,N. glauca,N. leoniiandN. dombeyiconformed to the seed viability equation of Ellis and Roberts; sensitivity of longevity to temperature was quantitatively similar to that of crop seeds, sensitivity to moisture was somewhat less, and a low-moisture-content limit to the equation was detected at 4.8% moisture content in hermetic storage at 65 °C, and possibly similar moisture contents at 30–40°C. These five species show orthodox seed storage behaviour. Therefore,ex-situconservation of theseNothofagusspecies in seed banks is possible, but the quality of seed lots collected requires attention. Seed storage behaviour was not defined inN. pumilio: initial seed quality was poor and loss of viability was detected over 2 years at 0°, –10° and –20°C at 2.7% moisture content, but not at 5.2%. The results confirm that the economy of nature in seed storage physiology extends to forest tree seeds, but the repeated observation of reduced sensitivity of longevity to moisture in forest tree seeds requires further investigation.

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Seed desiccation tolerance and germination of four Puya (Bromeliaceae) high-andean tropical species from Colombia

Caldasia ◽

10.15446/caldasia.v40n1.67740 ◽

2018 ◽

Vol 40 (1) ◽

pp. 177-187

Author(s):

Manuela Calderón-Hernández ◽

Laura Victoria Pérez-Martínez

Keyword(s):

Desiccation Tolerance ◽

Ex Situ ◽

Tropical Species ◽

Seed Desiccation

La conservación ex situ de semillas es una de las formas más efectivas de preservación de la biodiversidad y especialmente de la diversidad genética. En el marco del cambio climático su aplicación es una estrategia importante que se debe fortalecer e integrar con la conservación in situ. El objetivo del presente trabajo fue estudiar la tolerancia a la desecación y la germinación de cuatro especies del género Puya y proporcionar herramientas para su conservación ex situ. Estas especies están distribuidas en el páramo, un ecosistema amenazado a pesar de su valor como reservorio y proveedor de agua para la población urbana. En las semillas se realizó la toma de medidas morfológicas y del contenido de humedad (CH), se realizaron ensayos de germinación en tres contenidos de humedad (semillas frescas, 10–12 % y 3–5 %) y se evaluó el porcentaje de germinación y tiempo medio de germinación. Se registró una germinación superior al 80 % en las cuatro especies y no se encontraron diferencias significativas al disminuir el CH. El tiempo medio de germinación no varió entre especies y la viabilidad fue alta comparada con otras especies de páramo. Los resultados indican que son semillas ortodoxas y las variables morfológicas apoyan esta tendencia. Por tanto, este género presenta un gran potencial para ser conservado en bancos de germoplasma lo que contribuye a la conservación de su diversidad, con las cuales se pueden implementar protocolos de germinación para la propagación y reintroducción en programas de restauración.

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Drilling down hotspots of intraspecific diversity to bring them into on-ground conservation of threatened species

10.1101/419788 ◽

2018 ◽

Cited By ~ 1

Author(s):

Mauro Zampiglia ◽

Roberta Bisconti ◽

Luigi Maiorano ◽

Gaetano Aloise ◽

Antonino Siclari ◽

...

Keyword(s):

Genetic Diversity ◽

Threatened Species ◽

Management Practices ◽

In Situ Conservation ◽

Intraspecific Diversity ◽

Ex Situ ◽

Spatial And Temporal Variation ◽

Conservation Priorities ◽

Global Changes

AbstractUnprecedented rates of biodiversity loss rise the urgency for preserving species ability to cope with ongoing global changes. An approach in this direction is to target intra-specific hotspots of genetic diversity as conservation priorities. However, these hotspots are often identified by sampling at a spatial resolution too coarse to be useful in practical management of threatened species, hindering the long-appealed dialog between conservation stakeholders and conservation genetic researchers. Here, we investigated the spatial and temporal variation in species presence, genetic diversity, as well as potential risk factors, within a previously identified hotspot of genetic diversity for the endangered Apennine yellow bellied toad Bombina pachypus. Our results show that this hotspot is neither a geographically homogeneous nor a temporally stable unit. Over a time-window spanning 10-40 years since previous assessments, B. pachypus populations declined in large portions of its hotspot, and their genetic diversity levels decreased. Considering the demographic trend, genetic and epidemiological data, and models of current and future climatic suitability, populations at the extreme south of the hotspot area still qualify for urgent in-situ conservation actions, whereas northern populations would be better managed through a mix of in-situ and ex-situ actions. Our results emphasize that identifying hotspot of genetic diversity, albeit essential step, does not suffice to warrant on-ground conservation of threatened species. Hotspots should be analysed at finer geographic and temporal scales, to provide conservation stakeholders with key knowledge to best define conservation priorities, and to optimize resource allocation to alternative management practices.

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One-step fitting of seed viability constants for two Australian plant species, Eucalyptus erythrocorys (Myrtaceae) and Xanthorrhoea preissii (Xanthorrhoeacea)

Australian Journal of Botany ◽

10.1071/bt12171 ◽

2013 ◽

Vol 61 (1) ◽

pp. 1 ◽

Cited By ~ 1

Author(s):

A. D. Crawford ◽

F. R. Hay ◽

J. A. Plummer ◽

R. J. Probert ◽

K. J. Steadman

Keyword(s):

Survival Data ◽

Seed Viability ◽

Seed Storage ◽

Storage Conditions ◽

Gene Bank ◽

Seed Longevity ◽

Ex Situ ◽

Australian Species ◽

One Step

Long-term ex-situ seed storage under controlled conditions in gene banks has become an important tool for conserving threatened Australian plants; however, there is scant information about the seed longevity of most species. The aim of the present study was to determine whether the seed longevity of two contrasting Australian species could be modelled using the seed viability equation, and whether the universal temperature constants are applicable to these species. Seeds of Eucalyptus erythrocorys F.Muell. (Myrtaceae) and Xanthorrhoea preissii Endl. (Xanthorrhoeaceae) were aged at moisture contents ranging from 3.9 to 15.7% and temperatures between –20 and 60°C. Survival data were fitted to the seed viability equation in one step and the species constants for each species determined. Both E. erythrocorys and X. preissii seeds exhibited orthodox seed storage behaviour whose longevity could be modelled using the seed viability equation. The viability constants were KE = 8.81, CW = 4.97, CH = 0.0412 and CQ = 0.000379 for E. erythrocorys and KE = 8.77, CW = 5.29, CH = 0.0382 and CQ = 0.000473 for X. preissii. The universal temperature constants could not be used without a significant increase in error. The storage behaviour of these two Australian species is in keeping with that of orthodox species from around the world. Predictions are that E. erythrocorys will be long-lived under gene bank conditions, whereas X. preissii would be moderately long-lived. Current long-term gene bank storage conditions appear suitable for storage of these species; however, recommendations for short-term storage need to be re-evaluated.

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