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The science and economics of ex situ plant conservation
Abstract
Ex situ seed storage underpins global agriculture and food supplies and enables the conservation of thousands of wild species of plants within national and international facilities. As an insurance policy against extinction, ex situ seed conservation is estimated to cost as little as 1% of in situ conservation. The assumptions, costs, risks and scientific challenges associated with ex situ plant conservation depend on the species, the methods employed and the desired storage time. Recent, relatively widespread evidence of less than expected longevity at conventional seed bank temperatures, innovations in the cryopreservation of recalcitrant-seeded species and economic comparators provide compelling evidence that ultra-cold storage should be adopted for the long-term conservation of plants. Policy instruments, such as the Global Strategy for Plant Conservation (2011-2020), should respond to the evidence base and promote the implementation of cryopreservation for both tropical and temperate plants.
... Ex situ conservation strategies preserve plants or plant germplasm away from the site of natural occurrence (Given, 1994). The most widely employed technique, known as seed banking, is the storage of seeds that are dried and deep-frozen in 'conventional' conservation seed banks (Li and Pritchard, 2009). Seed banking allows the preservation of high levels of plant genetic diversity at relatively low cost, in minimal space and for comparatively long periods (Potter et al., 2017). ...
... Seed banking allows the preservation of high levels of plant genetic diversity at relatively low cost, in minimal space and for comparatively long periods (Potter et al., 2017). Seed collections safeguard against species extinction in the wild Li and Pritchard, 2009;Liu et al., 2020), and they provide an immense resource for researching biological and physiological processes crucial to understanding how plant communities and ecosystems function, now and in the future (Hay and Probert, 2013;Martyn Yenson et al., 2021). Conventional seed banking relies on the following sequential steps: ...
... Germination also enables collections to be used to regenerate plants for translocation and to replenish seed lots. Finally, germinable collections underpin seed-based research into optimising seed banking methods Li and Pritchard, 2009;Hay and Probert, 2013;Liu et al., 2020;Martyn Yenson et al., 2021), and understanding the seed biology and ecology of plant communities (e.g., Satyanti et al., 2018;Hodges et al., 2021). Several studies report challenges in germinating seeds of species from TM zones citing high seed predation, limited seed longevity and long lag times to germination (Holl et al., 2000;Wenny, 2000;Athugala et al., 2021;Baskin et al., 2020). ...
... MAPs can be conserved by botanic gardens through propagation and cultivation protocols, as well as breeding and domestication programs ( Maunder, Higgens, and Culham 2001). Genetic diversity of medicinal plants can be stored better ex situ in seed banks than in botanic gardens, and seed banks should be used to preserve biological diversity ( Schoen and Brown 2001;Li and Pritchard 2009). Royal Botanic Gardens in Britain is the most noteworthy seed bank ( Schoen and Brown 2001). ...
... Royal Botanic Gardens in Britain is the most noteworthy seed bank ( Schoen and Brown 2001). By allowing quick access to samples, seed banks help conserve the remaining natural populations by providing information about their properties ( Schoen and Brown 2001;Li and Pritchard 2009). To restore wild populations, seed banks must reintroduce plant species back into the wild and assist in their reintroduction ( Li and Pritchard 2009). ...
... By allowing quick access to samples, seed banks help conserve the remaining natural populations by providing information about their properties ( Schoen and Brown 2001;Li and Pritchard 2009). To restore wild populations, seed banks must reintroduce plant species back into the wild and assist in their reintroduction ( Li and Pritchard 2009). ...
... Ex situ plant conservation is the preservation of plants or germplasm outside of the areas and situations in which the species naturally occur. Techniques include the maintenance of cultivated collections in botanic gardens or arboreta; cryopreservation of seeds, embryos, or other tissues in liquid nitrogen; or storage of dried and deep-frozen seeds in seed banks (Li and Pritchard 2009;Mounce et al. 2017). Of these techniques, the storage of seeds in seed banks (also known as 'conventional seed banking') is the most used, due to the ease of preserving high levels of genetic diversity for relatively low cost, in minimal space, and for long time periods ). ...
... The process of seed conservation in a conventional seed bank involves the desiccation of seeds to the point that they are in equilibrium with 15% relative humidity air, before storage at −20°C (Li and Pritchard 2009). Most seed plant species (estimated at approximately 92%; Wyse and Dickie 2017) produce seeds that survive this drying and freezing process and are referred to as 'orthodox' (also known as 'desiccation-tolerant') species (Berjak and Pammenter 2008). ...
Context Globally, plant species are facing numerous threats; an issue particularly acute for island floras, which often exhibit high levels of endemism. Ex situ conservation in seed banks is an important tool for plant conservation. However not all species’ seeds can be stored in conventional seed banks. Data on seed storage behaviour are therefore vital for conservation decision making. Aims To review available seed storage information for the New Zealand (NZ) indigenous seed plant flora, 86% of which are endemic. Methods We compiled seed storage information for the NZ flora from databases and existing literature, and used boosted regression trees models to investigate predictors of seed storage behaviour for NZ woody plants. We used existing global models to predict the likely storage behaviour for the NZ woody flora where this was unknown, to examine the overall contribution that conventional seed banking could make towards NZ plant conservation. Key results Data were available for 412 of 1823 seed plants, of which 83% produced orthodox seeds that can be stored in a conventional seed bank. Of the woody flora, the incidence of non-orthodox seeds was positively correlated with seed mass, plant height, biotic dispersal, and habitat diurnal temperature range. Eighty-one percent of the woody flora are predicted to produce orthodox seeds. Conclusions and implications Conventional seed banking is likely to be suitable for a high proportion of the NZ flora. However, work is required to gain further seed storage behaviour data for NZ species, and to develop protocols for alternative ex situ conservation strategies for non-orthodox species, especially those facing in situ conservation threats.
... The conservation effort has mainly focused on dryland habitats as species adapted to hot, dry environments may have evolved longer lifespans in the dry state and are suitable for preservation in seed banks (Li and Pritchard 2009). As the conservation effort evolved, new collaborative projects emerged to deliver innovative solutions for not only conservation but also for agriculture, horticulture, forestry, and habitat restoration. ...
... When you add in six multipurpose species bear recalcitrant seeds, at least 288 identified UP species can be described as 'exceptional' plants that have seeds that either are desiccation sensitive or that store poorly when dry in a conventional seed bank. Not only is there a need for multiple and diverse approaches to the preservation of seeds, as conventional seed banking does not suit all species (Li and Pritchard 2009;Dickie 2018;Pence et al. 2020), but also a requirement to characterise the seed biology of a wide range of species, particularly from the tropics (Visscher et al. 2022). ...
A substantially rich diversity of the world’s recorded useful plants (UPs) is captured within the Millennium Seed Bank collection hosted by the Royal Botanic Gardens, Kew, at Wakehurst, UK with 13,598 species (34%) belonging to 3696 genera and 325 families. This constitutes just over half of the total accessions and one third of the species and covers all 9 continents, 8 realms, 14 biomes, 34 biodiversity hotspots and 175 countries. The most common beneficial use category within the captured diversity is medicinal, then species with environmental, material, and human food value. About 86% of conserved UP species have a ‘Least Concern’ conservation status but 8% are identified as globally threatened. The advantages of mutual, continued, and long-term partnership (e.g., Mexico) are showcased when conserving plants important for local communities and addressing conservation challenges beyond seed banking. However, the geographic coverage suffers from a lack of partnerships with some parts of the world. Also, a low number of accessions contributed from many countries means that insufficient native range is yet to be captured for many species. This is particularly the case for restricted or narrow distribution species from families or genera with a high incidence of recalcitrant or short-lived seeds. Future planning must tailor better to cover the spatial distribution patterns for individual species, thereby improving the number of accessions and geographical coverage for those captured. Moreover, seed biology research should characterise desiccation tolerance and develop complementary, novel conservation methods, such as cryopreservation, to strengthen conservation options for UP species.
... Here, the correct propagation and horticultural management of plants are indispensable (Rae, 2011;Cibrian-Jaramillo et al., 2013;Ensslin and Godefroid, 2019). However, this is a relatively costly option that requires high maintenance and a considerable amount of space, where minimal genetic diversity is preserved and is directly exposed to biotic (e.g., pests) and abiotic (e.g., climatic) threats (Li and Pritchard, 2009;Pence, 2011). In addition to field collections, other valuable resources for the ex situ conservation of RS species are in vitro collections. ...
... Ex situ conservation of RS species as field collections and the effects of climate change on their production and culture 2.1. Effects of climate change on RS species growth in field collections Plants propagated in botanical gardens, arboretums, field GeneBanks, or plant nurseries represent a valuable option for ex situ conservation of RS species (Li and Pritchard, 2009;Primack and Miller-Rushing, 2009;Breman et al., 2021;Primack et al., 2021). However, climate change projections introduce large uncertainties around the sustainable use of field collections due to the increase in the frequency of extreme climate events (flooding, late frosts, intensive summer droughts, heat waves, and amongst other events). ...
Recalcitrant seeds are characterized by desiccation and freezing sensitivity, and short storage longevity. These physiological attributes obviate their ex situ conservation in conventional seed banks, where seeds are stored dry at sub-zero temperatures (typically, 15% relative humidity and-20 • C) for extended periods of time. Propagation of plants for field collections (e.g., botanical gardens, nurseries, and arboretums) is a valuable ex situ conservation option. However, these collections are relatively costly, require high maintenance, preserve limited genetic diversity and/or are directly exposed to biotic (e.g., pests) and abiotic (e.g., climatic) threats. Therefore, recalcitrant-seeded (RS) species are dependent on cryopreservation for their safe and long-term ex situ conservation. Different explant sources such as whole seeds, zygotic embryos, dormant buds, shoot tips, and pollen, can be used for plant propagation of RS species in field collections as well as for their cryopreservation. The success of the propagation or the cryopreservation of these explants often depends on their developmental status, vigor, and/or tolerance to desiccation and chilling/freezing. These attributes are modulated by the environment where the donor plant grows and we hypothesize that climate change, by affecting these biological attributes, would impact the success of explant propagation and cryopreservation. To support this hypothesis, we have reviewed how temperature changes and drought, the two main climate change scenarios, affect the main biological attributes that are directly involved in the success of ex situ conservation of tropical and temperate RS species. In general, increases in temperature and drought will negatively affect plant development in field collections and the quality of the explants used in cryopreservation. Consequently, field collections of RS species may need to be moved to more suitable places (e.g., higher latitudes/altitudes). Additionally, we may find a reduction in the success of cryopreservation of RS species germplasm directly harvested from field collections. However, we cannot always generalize these effects for all species since they often depend on the origin of the species (e.g., tropical and temperate species tend to respond to climate change differently), the genotype, the adaptive genetic potential of each population, and the severity of the environmental change. On the other hand, the increase in temperatures and water stress in donor plants at high-latitude areas and also some tropical environments may favor the production of seeds and seedlings better adapted to drying, and hence, increase the success of plant propagation and zygotic embryo cryopreservation.
... Consequently, it is important to preserve desirable Castanea germplasm. However, Castanea species produce recalcitrant, desiccation sensitive seeds that cannot be preserved in conventional seed banks, and cryopreservation is considered to be the only viable method for the long-term ex situ conservation of these species [4,6,21,31,36]. ...
A cryopreservation protocol has been developed for embryogenic cultures (ECs) of Castanea mollissima, an important economic species of the Castanea genus in China. We achieved 100 % regrowth when ECs were treated with Plant Vitrification Solution 2 (PVS2) for 30, 60 and 90 min on ice. Optimal PVS2 treatment for cryopreservation was determined to be 30 min on ice based on the highest biomass regrowth after thawing. Fluorescein diacetate (FDA) staining could rapidly and reliably determine post-thaw cell viability and its use facilitated the optimization of the cryopreservation protocols. Although the proliferation rate of the re-established ECs remained largely unchanged compared to non-cryopreserved ECs, the capacity of the re-established ECs to differentiate (on two media) into somatic embryos nearly doubled to approximately 2200–2300 globular somatic embryos per 1 g of re-established ECs. Based on cell cluster size analysis, this enhanced growth is primarily attributed to the presence of significantly greater cell clusters with a diameter of 100–200 μm, which have the highest level of differentiation ability. In order to understand the increased embryogenic potential following cryopreservation, we analyzed the expression of key genes related to somatic embryogenesis. Genes CmWUS and CmABP1 were downregulated while CmLEC1, CmAGL15, CmGRF2, and CmFUS3 were upregulated in re-established ECs when compared to non-cryopreserved ECs.
... Despite the methodological limitations, our findings may provide useful information for threatened species conservation and invasive species mitigation strategies. Reintroducing threatened species to new areas is a classic conservation approach (Li & Pritchard, 2009). However, reintroduced populations may still be affected by their native threat factors if these threats are not removed (Rocha & Bergallo, 2012). ...
Article impact statement: A global picture of the conservation-invasion paradox would help threatened species' conservation and invasive species management. Abstract The conservation-invasion paradox (CIP) refers to a long-term phenomenon wherein species threatened in their native range can sustain viable populations when introduced to other regions. Understanding the drivers of CIP is helpful for conserving threatened species and managing invasive species, which is unfortunately still lacking. We compiled a global data set of 1071 introduction events, including 960 CIP events (successful establishment of threatened species outside its native range) and 111 non-CIP events (unsuccessful establishment of threatened species outside its native range after introduction), involving 174 terrestrial vertebrates. We then tested the relative importance of various predictors at the location, event, and species levels with generalized linear mixed models and model averaging. Successful CIP events occurred across taxonomic groups and biogeographic realms, especially for the mammal group in the Palearctic and Australia. Locations of successful CIP events had fewer native threat factors, especially less climate warming in invaded regions. The probability of a successful CIP event was highest when species introduction efforts were great and there were more local congeners and fewer natural enemies. These results can inform threatened species ex situ conservation and non-native invasive species mitigation.
... (a) Storage Conditions Maintenance: Maintaining optimal storage conditions, such as temperature and humidity, is crucial for preserving seeds. Technical challenges arise in creating and sustaining these conditions, especially in the face of unpredictable climate changes that may require continuous adjustments (Li and Pritchard 2009;Hay et al. 2021). (b) Periodic Viability Testing: Ensuring seed viability over time is essential. ...
The future of biodiversity maintenance and crop security faces significant threats due to climate instability. Ex situ seed banks can serve as refuges for major crop varieties and their wild relatives in catastrophic situations. However, managing these repositories requires regular quality control to ensure the viability of preserved samples for future regeneration. In this opinion, we have identified significant challenges in traditional seed bank management, including difficulties in scheduling seed viability tests for a diverse collection and the burden of replenishing depleted stored samples. We have also examined the advantages and disadvantages of different seed viability tests used in long-term seed repositories for ex situ biodiversity conservation. While the ultimate goal of seed conservation is to achieve non-destructive methods of viability estimation, the additional predictive potential of such tests can revolutionize traditional management practices. Timely replenishment of decaying seeds can ensure sustainable genomic storage and positively impact agricultural legacy and genetic diversity preservation. This opinion provides an open platform to review current management practices and explore alternative and efficient ways to secure the ‘ultimate repository’ of agricultural legacy and genetic diversity.
... In addition, it is also crucial to estimate genetic diversity at the species level, which can be associated with the potential of the species to adapt to new environmental conditions (Lustenhouwer et al., 2018;Foden et al., 2019). These studies will not only allow a more effective planning of the regional protected area network for "in-situ" conservation policies, but also the implementation of "ex situ" (outside natural habitat) conservation programs based on different techniques (such as long-term germplasm storage in seed banks, plant tissue culture, and ex situ cultivation, Li and Pritchard, 2009) to protect the most vulnerable species and lineages in the next years. ...
Climate change impact on species can be heterogeneous depending on their environments, exposure, and intrinsic characteristics. Likewise, global warming may have an uneven effect on lineages, depending on whether phylogenetic conservatism or divergence of ecological niches predominates during clade diversification, imposing a higher risk to species groups from certain regions, habitats and lineages. This study evaluates the impact of future climate change on Menonvillea, a genus with 24 species distributed along the Andes and contiguous regions of the Southern Cone. The impact on the main phylogenetic, ecological and biogeographic groups is evaluated, also analyzing the effect on its richness and phylogenetic diversity. Results show a strongly negative impact on most species of the genus. However, the greatest pressure seems to be recovered for high Andean species, mainly from the southern portion of the Southern Andes (between 34°S–53S°), and mostly included in Menonvillea sect. Cuneata. Richness appears to be more impacted in high Andean regions, and the loss of phylogenetic diversity is greater than expected at random. These results highlight the strong negative impact that climate change can induce on lineages distributed in the Andean-Patagonian region, and that show patterns of phylogenetic niche conservatism.
... Among the various ex situ conservation methods, seed storage in genebanks is the most convenient for long-term conservation of plant genetic resources. Genebanking is the most cost-effective ex situ conservation strategy (Li and Pritchard, 2009) and was developed for the storage of predominantly orthodox seeds to maintain (in perpetuity) the allelic integrity and identity of a sample (Frankel and Soulé, 1981). Thus, a genebank requires essential infrastructure for short-and long-term seed storage and the efficient management of germplasm from safety backup to regeneration and characterization, germplasm distribution, and data management (Engels and Visser, 2003). ...
Gene banking is the most cost-effective ex situ strategy for conserving plant genetic resources. It was developed for the storage of predominantly orthodox seeds. To maintain long-term seed survival and integrity of the conserved germplasm in the genebanks, seed viability testing and regeneration should be done occasionally. The seed viability tests inform which accessions need regeneration. In addition, adequate evaluation and characterization of the conserved germplasm enhances their wider utilization. The Genetic Resources Research Institute (GeRRI) in Kenya and Korea-Africa Food and Agriculture Cooperation Initiative (KAFACI) undertook a joint project entitled Improvement of Technology on Conservation of Genetic Resources from 2015 and 2018. Korea-Africa Food and Agriculture Cooperation Initiative was funding the project, while GeRRI was the implementing institution. One of the objectives was to carry out morphological characterization of sesame, millet and cowpea accessions conserved at GeRRI's genebank to promote their conservation and utilization. A total of 376 accessions of two crops (216 cowpeas and 160 sesame) were withdrawn from the conservation unit at GeRRI's genebank and characterized at KALRO's Perkerra field site during the 2018 long rains season. About 78 % of the cowpea accessions had reached 50 % flowering within 60 days after planting. Over 80 % of sesame accessions yielded ≤ 400kg of seeds per hectare. Multivariate analyses were performed to establish similarity patterns. Principal Component Analysis (PCA) showed that four components had eigenvalues >1, accounting for 61.23 % of the total variability among the cowpea accessions. The first four PCs accounted for 63.95 % of the total variability for the sesame accessions. In addition, all the quantitative characters considered were important in describing phenotypic variation in these sesame accessions. The study has shown that there is wide variability among cowpea, as well as sesame accessions, conserved at GeRRI's genebank. All the quantitative characters measured in this study were important in describing phenotypic variation among cowpea and sesame accessions.
... This interplay between dispersal limitations and phylogenetic niche conservatism can increase their vulnerability to climate change, as species have to disperse to areas that are becoming newly suitable under climate change, and if populations cannot disperse at the velocity of environmental shifts, they may only persist in remaining refuges (Wiens et al., 2010). Therefore, within Onuris, ESU3 appears to be the most threatened, highlighting the need to consider assisted migration or other ex-situ (outside the natural habitat) strategies (e.g., cultivation, long-term germplasm storage in seed banks, and plant tissue culture) for its conservation (Li and Pritchard, 2009). Size of climatic niche in the northern lineage was also found to be greater than in the southern lineage species. ...
Anthropogenic climate change has been identified as one of the main threats to current biodiversity, particularly for mountain species, which are especially sensitive to reductions of suitable habitat. Climate change impact assessments through correlative models have become a widely used tool for evaluating vulnerability of species to global warming. However, interpreting these results in an evolutionary context is essential to understand the phylogenetic structure of the predicted impact, as well as the potential evolutionary responses. The present study evaluates the impact of climate change on the Andean-Patagonian genus Onuris, interpreting the effect on its species and main phylogenetic groups. We first estimated a species phylogeny using both nuclear ribosomal and plastid data, which was then used to interpret the evolution of climatic niches and characterize the vulnerability of different species, evolutionary significant units (ESUs), and main lineages to climate change. Evaluations were conducted at the species level using species-specific metrics and at the genus level with emergent metrics such as richness, phylogenetic diversity, and shared response to local extirpation. Analyses showed that closely related species exhibit greater climatic niche similarity, suggesting a possible pattern of phylogenetic niche conservatism for divergence in the genus, with the greatest niche divergence recovered between lineages distributed in central-northern and southern Andean-Patagonian region. Species and ESUs of the lineage distributed in the southernmost portion of Patagonia (ca. 47°S–55°S) were most negatively affected under the different scenarios and models tested. The results also indicated a greater impact on richness than on phylogenetic diversity, mainly due to the establishment of the northern lineage in future projections over the range of the southern lineage. However, predictions show a pronounced negative effect of climate change for the entire genus. Likewise, results obtained suggest the high vulnerability of the current biota in the southern end of the Andean-Patagonian region
... via the creation of propagation and culture guidelines, as well as via the implementation of domestication and variety breeding programs, arboreta can play a further role in the conservation of medicinal plants [130]. However, seed banks are advised to help maintain the ecological species since they provide a superior means of storing the genetic diversity [131,132]. ...
On October 20 to 22, 1994, an interim annual meeting was hosted by the American Society of Pharmacognosy in San Jose, Costa Rica. During the symposium, subject experts from all over the nation shared their insights on issues adjoining intellectual property rights in kith and kin of drug development from naturally derived compounds, plant conservation, and international conventions on bioprospecting. To guarantee that the genomic assets of all nations will be developed for the benefit of human race and observant of recent current stratagems for the benefits, scientific collaboration will be warranted. The core issue of the conferences, the fair and justifiable sharing of the compensations of bioprospecting, was articulated from a variety of opposing standpoints, as can be seen from the summaries of presentations. These divergent belvederes are the consequence of various explanations. Different viewpoints to the larger society are formed by the multiplicity midst the world, particularly those in developing nations. Additionally, a lot of the discussion and negotiations around access to resources wherever they are discovered are clouded and perplexed by the excessive emphasis on the unearthing, expansion, and business of medications as the inimitable outcome of the exploitation of genetic resources. It should be underlined that academic and research institutions would fail, due to a successful outcome from bioprospecting product. Instead, it is critical to understand that other vital goals may also be achieved, particularly in the fields of technology transfer and capacity building. The symposiums help advance research on intellectual property rights (IPR), naturally occurring bioactive substances, and resource conservation for the moral use of conventional medicines, as well as for the development of a country’s economy and healthcare system. In light of the foregoing information, an effort has been made in this chapter to disseminate recent scientific advancement and to comprehend the interrelationship between IPR, bioactive of natural origin, and conservation of resources in order to establish a smooth avenue for traditional drugs and medicine thereof.
... By contrast, X. undulatum seeds lost 13% of their germination rate during the same interval [53]. Such varying results to conventional banking conditions have strengthened the requirement for research into the cryostorage behavior of orchid seeds and the seeds of other species [54]. According to Seaton and Hailes [7], silica gel reduces Cattleya aurantiaca seed moisture to a level that results in a rapid loss of viability. ...
... filled, viable and germinable) seeds and thereby persistence of the population. When quality seeds are available, ex situ conservation of seeds, in seedbanks, provides one of the most efficient and cost-effective ways of accessing genetic diversity for re-establishment of wild populations (Laliberté 1997;Offord et al. 2004;Cochrane et al. 2007;Li and Pritchard 2009). Use of stored seeds in re-establishment practices depends on successful germination. ...
Context Knowledge of seed biology is imperative for effective curation and utilisation of seeds. Aims We studied the seed biology and reproduction of Geijera parviflora, a species suitable for ecological restoration and ornamental horticulture that has largely been overlooked because of issues with unreliable germination and viability. Methods Germination in response to dormancy-breaking treatments and soil seed burial, and variation in germination at an inter-population level were assessed for G. parviflora. Seed storability in a conventional seedbank was tested. Floral phenology was assessed. Key results Germination of untreated and seed coat removed seeds were 0 ± 0.0% and 67 ± 5.5% respectively. Seed germination varied between 21.9 ± 1.8 and 66.6 ± 5.5% at an inter-population level. Seeds buried in soil for 6 months showed 11.7 ± 0.8% germination without any treatment. All seeds buried for 12 months were non-viable. Drying seeds from 11.4 ± 0.19% to 5.79 ± 0.17% moisture content resulted in 40% less germination. Visual observation of floral attributes confirmed the presence of orange-coloured pollen grains for 3.5 ± 0.48 days from floral opening. The stigmatic surface became shiny 3.5 ± 0.21 days after floral opening. Conclusion Seeds of G. parviflora demonstrate physiological dormancy; treatments that remove seed coat resistance against embryo growth enable germination. Local environmental conditions may explain the inter-population variation in germination. Seeds are short-lived in soil and ex situ seedbank conditions. In soil, seeds release dormancy at the end of first winter, so seeds are available to germinate the following spring/summer with high rainfall. Floral phenology assessment indicated protandrous sequential hermaphroditism, which may reduce the probability of self-pollination in G. parviflora. Implications This knowledge supports use of G. parviflora in ecological restoration and horticulture.
... However, long-term conservation of such a large volume of diverse germplasm remains a challenging mission, as genetic erosion can also occur within genebanks (Fu 2017). Genebanking represents the most costeffective ex situ conservation strategy (Li and Pritchard 2009) and was developed for the storage of predominantly orthodox seeds under low seed moisture content and temperature. However, even following FAO standards (FAO 2014) with seed viability tests and regeneration, seeds in long-term storage will lose their viability (Walters et al. 2005) and genetic changes will occur (Roberts 1973). ...
Conserving more than 7 million plant germplasm accessions in 1,750 genebanks worldwide raises the hope of securing the food supply for humanity for future generations. However, there is a genetic cost for such long-term germplasm conservation, which has been largely unaccounted for before. We investigated the extent and variation of deleterious and adaptive mutations in 490 individual plants representing barley, wheat, oat, soybean, maize, rapa, and sunflower collections in a seed genebank using RNA-Seq technology. These collections were found to have a range of deleterious mutations detected from 125 (maize) to 83,695 (oat) with a mean of 13,537 and of the averaged sample-wise mutation burden per deleterious locus from 0.069 to 0.357 with a mean of 0.200. Soybean and sunflower collections showed that accessions acquired earlier had increased mutation burdens. The germplasm with more years of storage in several collections carried more deleterious and fewer adaptive mutations. The samples with more cycles of germplasm regeneration revealed fewer deleterious and more adaptive mutations. These findings are significant for understanding mutational dynamics and genetic cost in conserved germplasm and have implications for long-term germplasm management and conservation.
... With increasing environmental pressures on many native plant ecosystems and the looming extinction crisis, ex situ collections of plant material are becoming increasingly valuable. Seed banking is one of the most cost-effective means of ex situ storage (Engels and Engelmann 1998;Li and Pritchard 2009) and apart from providing some level of longterm security, good quality seed collections have multiple applications, including plant propagation for restoration (León-Lobos et al. 2012) and conservation (O'Donnell and Sharrock 2017;Chapman et al. 2019;White et al. 2023), breeding programs (Byrne et al. 2018), horticulture (Li et al. 2016), and research (Sommerville et al. 2013;Everingham et al. 2021;Rauschkolb et al. 2022). Sourcing seed from wild populations can be time consuming and often require multiple visits to remote areas for each accession (Griffith et al. 2015). ...
Context Given the effort and resources that go into collecting and maintaining seed collections, it is crucial that we maximise their usefulness. Conservation, restoration and research rely heavily on good quality collections in order to establish new populations, create habitat, minimise extinction and address scientific questions. Aims Although seed viability, excellent metadata and genetic representativeness make for good quality collections, we provide 10 detailed reasons why the maintenance of separate maternal lines further increases the quality and usefulness of seed collections. Key results Maternal line seed collections can accommodate new information, this is especially important given the increasing longevity of seed collections. For example, maintaining separate maternal lines facilitates accommodation of taxonomic changes, minimises the impact of erroneous plant identifications, and facilitates separation of polyploid races, hybrids and inappropriate lineages. Separate maternal line collections also facilitate better estimates of the genetic diversity captured, and consequently better inform conservation translocations and the establishment of conservation gardens and seed orchards. Separate maternal line collections can also expedite breeding for specific traits, such as disease resistance or other selective challenges that impact on biodiversity conservation. New seed microbiome data show how only some maternal lines contain pathogenic fungi, reminding seed collectors and collections managers that contamination can be better contained by keeping each maternal line separate. Conclusions and implications Maintaining separate maternal lines is a simple and effective way to increase the value of seed collections for multiple applications.
... Many tropical tree species' seeds are recalcitrant, so cannot be dried and stored (Corlett 2009;Li & Pritchard 2009), and no known tropical peatland tree species display seed dormancy (Graham et al. 2017). Unless seed/wildlings can be sown or transplanted directly from nearby forest (e.g. ...
Reforestation is promoted to address the dual global climate and biodiversity crises. This is particularly relevant for carbon‐rich, biodiverse tropical peatlands, for which active reforestation typically involves two post‐germination stages: nursery rearing of seedlings, then outplanting. Yet, linkages between these stages and cumulative seedling performance are rarely quantified during tropical peatland reforestation. By monitoring tree seedling survival and growth, we investigate factors influencing seedling performance (species identity, seedling source, treatments, and climate), whether nursery performance predicts outplanting performance, and calculate cumulative survival (nursery plus outplanting) in Sebangau National Park, Indonesian Borneo. Standardized survival at 2 years was higher in the nursery (mean 67% across 40 species) than outplanting (44% across 24 species). For nursery and outplanting, species identity was the main source of variation in survival and height growth. Seedling source, treatments, site condition, and precipitation had no significant impact on survival but did influence growth in some cases. Nursery survival did not predict outplanting survival, but nursery height did predict outplanting height. Across species, around a quarter of seedlings survived from nursery to outplanting over 4 years. Cumulative survival represents a more realistic basis for assessing the genetic and other resource costs of tropical peatland reforestation. Our two‐phase approach identified outplanting as the greater bottleneck to cumulative seedling survivability. We argue that the nursery stage may be used to harden seedlings for degraded peatland conditions by selecting more relevant treatments (e.g. flooding) and screening for resilience to common disturbances (e.g. fire) to enhance outplanted, and thus cumulative, seedling survival.
... Environmental damage due to human activities and overcollection of the orchids trigger their extinction in their natural habitats. Plant conservations, both in situ conservation (in their natural habitats; Chen et al., 2009;Havens et al., 2014) and ex situ conservation (outside their natural habitats; Havens et al., 2006;Li and Pritchard, 2009;Mounce et al., 2017) need to be done to reduce the threat of extinction for these orchids. Conservation of plant genetic resources is an important factor in food security and biodiversity. ...
D. bicaudatum orchid has become threatened with extinction. Environmental damage due to human activities and overcollection of orchids has triggered the extinction of orchids in their natural habitat. In situ and ex situ conservation measures need to be taken to reduce the threat of extinction for orchids. This research aims to investigate the effect of paclobutrazol (PBZ) on culture mediums as a plant growth inhibitor, one of which is in vitro conservation measures, and was conducted experimentally using a completely randomized design. The independent variables were the concentrations of PBZ of 0, 1, 3, and 5 mg L-1, respectively, which were added to the growing medium in the form of solid MS medium. The medium-term conservation of D.bicaudatum orchids with the addition of paclobutrazol exhibited a very significant result. Inhibition of vegetative growth such as the number of leaves and root length was exhibited by 1-5 mg L-1 PBZ, while the stem diameter, as one of the dependent variables, increased more in all treatment groups than in the control group. Reduced number of roots occurred in the groups of treatments of 1 mg L-1 PBZ and 3 mg L-1 PBZ. Keywords: extinction, in Vitro culture, reduction
... In this regard, Li and Pritchard (2009) noted that seed longevity depends on plant species, storage management method, and storage period and that methods for extending seed longevity can make an important contribution to sustaining global agricultural, maintaining food supplies, and preserving thousands of plant species. Moreover, cryopreservation has been experimentally proven to enable the long-term preservation of seeds. ...
... Seed banking under dry (c. 3-7% moisture content) and cold (i.e., −18°C or in liquid N) conditions underpins ex situ plant conservation; it is cost effective and requires less space compared to in-situ methods (Li and Pritchard, 2009). To survive transfer to subzero temperature, seeds must be dried below the high moisture freezing limit (HMFL), which is related to seed oil content (SOC), being about 9% moisture content (MC) for a 50% SOC and just over 20% MC for very low SOC (Pritchard, 1995). ...
Introduction
Cryo treatment of dry seeds is known to attenuate the structure of fruit and seed coats, but little is known about the microstructural impacts of such treatment. The seeds of Tilia miqueliana are dispersed within a hard pericarp, the manual removal (hulling) of which is time-consuming and inefficient. Rapid hulling technology is urgently needed for sustainable production and convenience of edible nuts.
Methods
We explored the mechanistic basis of liquid nitrogen (N)-treatment weakening of the pericarp of T. miqueliana fruits using a range of microscopical, biophysical and chemical approaches.
Results
Liquid N treatment (40 s) resulted in lower pericarp contents of cellulose and hemicellulose, and increased amounts of lignin. Profound changes in cell structure and mechanical properties included the emergence of large holes and gaps between the mesocarp and endocarp cells. Also, the toughness of the pericarp decreased, whilst the hardness and brittleness increased, thereby changing the fracture type from ductile to brittle. Liquid N treatment of dry fruits followed by tapping with a hammer, reduced the number of damaged seeds three-fold and pericarp peeling time four-fold compared with manual hulling, whilst seed viability was not negatively affected.
Discussion
Comparable findings for the efficient and economical removal of hard covering structures from dispersal units of five more species from three other families following liquid N treatment indicates the potential application of our findings to large-scale production of seeds and seedlings for breeding, forestry and conservation/restoration purposes. Furthermore, it introduces a novel concept for postharvest treatment and pre-treatment of deep processing in nuts.
... In Sierra Leone, there is dearth of well-articulated information regarding the roles of botanical gardens that are needed for the development of integrative conservation approaches for plants, particularly those threatened plant species in the wild (Li and Pritchard, 2009). Understanding of key roles of botanical gardens of Sierra Leone would provide unique opportunities for plant biodiversity research, horticulture, and conservation biology in popular public places. ...
... All living tissue in trees can synthesize ethanol with limited oxygen supply (Kimmerer and MacDonald 1987;Kimmerer and Stringer 1988), but the quantities synthesized by a specific tissue vary considerably among species (Kimmerer and MacDonald 1987;MacDonald and Kimmerer 1993). The seeds viability is affected by genetic variations (Walters et al, 2005, Sasaki et al. 2015Nagel et al. 2016; the effects of the environment and (Ellis et al. (1982) or treatments with chemicals from degraded plants during sowing (Li & Pritchard 2009) and sprout length are the most common and visible features that are noticed after the ageing of the seeds. Ethanol degradation as an accelerated based chemical seed ageing indicator was tested for different cultivars of soybean (seed water content <10%). ...
Indonesia has a wide range of swampy lands that need to be recovered for safe agriculture. The swampy lands and vegetation are a source of soil contamination through root exudates that need serious improvement. The plant exudates in soil could disturb seed germination. This study aimed to determine the effect of ethanol vapor treatment on the decrease in the vigor of four soybean seed cultivars. This study used a randomized block design with two treatment factors, namely ethanol-based ageing treatments as the main factor and cultivars as subfactor. The observation variables consisted of the percentage of germination, growth rate, vigor index, sprout length and sprout dry weight. The results showed that there was an interaction effect between fast ageing time and ethanol treatments and soybean cultivars which caused a decrease in the seed vigor. The soybean seeds of the cv. Gema was able to maintain more vigor compared to the cv. Grobogan which experienced more decline in germination. The 5 minutes of ageing time induced fewer damages with the highest vigor while 20 minutes of ageing the seeds induced maximum damage with the lowest seed vigor.
... Data from (Davis et al. 2019). independent seed stores, can potentially encourage the identification and preservation of more resilient varieties (Li and Pritchard 2009). However, there are challenges in terms of the social impacts and financial capital required to operate seed banks effectively (Shapiro-Garza et al. 2020). ...
Climate change is adversely affecting coffee production, impact-ing both yields and quality. Coffee production is dominated by the cultivation of Arabica and Robusta coffee, species that represent 99% of production, but both will be affected by climate change. Sustainable management practices that can enhance the resilience of production and livelihoods to climate change are urgently needed as production supports the livelihoods of over 25 million people globally, the majority of whom are smallholder farmers located in the coffee belt spanning the tropics. These communities are already experiencing the impacts of climate change. We conducted a systematic review, identifying 80 studies that describe the direct and indirect impacts of climate change on coffee agroecosystems, or that identify agroecological practices with the potential to enhance climate resilience. Adverse environmental impacts include a reduction in area suitable for production, lower yields, increased intensity and frequency of extreme climate events, and greater incidence of pests and diseases. Potential environmental solutions include altitudinal shifts, new, resilient culti-vars, altering agrochemical inputs, and agroforestry. However, financial, environmental and technical constraints limit the availability of many of these approaches to farmers, particularly smallholder producers. There is therefore an urgent need to address these barriers through policy and market mechanisms, and stakeholder engagement to continue meeting the growing demand for coffee.
... Seed collections can often be placed in cold storage at secondary locations; however, many vegetatively propagated fruit, nut, and vegetable collections are maintained in field repositories, greenhouses, or tissue culture as the desired cultivars cannot be preserved through seed banking [1]. These actively growing collections are expensive to maintain at multiple locations and are at risk of contamination, plant pathogens, and pests [2,3]. Cryopreservation of shoot tips and dormant buds provides a safe, secure, and cost-effective method to back up vegetatively propagated genebank collections [1,4,5]. ...
Cryopreservation has emerged as a low-maintenance, cost-effective solution for the long-term preservation of vegetatively propagated crops. Shoot tip cryopreservation often makes use of vitrification methods that employ highly concentrated mixtures of cryoprotecting agents; however, little is understood as to how these cryoprotecting agents protect cells and tissues from freezing. In this study, we use coherent anti-Stokes Raman scattering microscopy to directly visualize where dimethyl sulfoxide (DMSO) localizes within Mentha × piperita shoot tips. We find that DMSO fully penetrates the shoot tip tissue within 10 min of exposure. Variations in signal intensities across images suggest that DMSO may interact with cellular components, leading to its accumulation in specific regions.
... In-situ, for example, by performing specific spatial conservation prioritizations using identified hotspots (provided in ESM4 in the Supplementary Material) as background area and specific algorithms such as those implemented in Marxan (Ball et al., 2009) or Zonation (Lehtomäki & Moilanen, 2013). Ex-situ (outside natural habitat) using the species lists associated with each hotspot (provided in ESM5, supplementary material) for the design of conservation programs based on different techniques such as ex situ cultivation, long-term germplasm storage in seed banks, and plant tissue culture -micropropagation (Li & Pritchard, 2009). ...
Given the accelerated rate of environmental degradation and climate change, there is an urgent need to protect biodiversity, especially endemic species with restricted ranges. However, which areas should be prioritized for protection remains a critical issue. A common approach to prioritizing conservation is to rank areas using species-level metrics. Nevertheless, biodiversity and threat patterns can become complex when the amounts of data increase. Here, we analyzed the distribution of 1570 Argentinean endemic plants using clustering of spatially associated species to disentangle distribution and threat patterns. We explored vulnerability levels in each cluster using mean values of species-level metrics of vulnerability, relating values obtained to the regions and environments they occupy. For each cluster we also identified its hotspots and evaluated the effectiveness of the current protected area network for their conservation. Results yielded nine main clusters, mostly differentiated by their geographic distribution and by the ecoregions they occupy. Metrics revealed disparity in vulnerability levels among clusters, with the highest values recorded for clusters related to the Central Puna in northwestern Argentina, to the Espinal, Humid Pampas, and Low Monte in the east of the country, and to the Patagonian steppe in the south. Likewise, coverage by protected areas was low for most hotspots, with the lowest values recorded for the Patagonian cluster. In particular, for hotspot of this cluster, located along the Patagonian steppe in southern Chubut and northeastern Santa Cruz provinces, analyses showed that it has both high levels of vulnerability and low levels of protection, giving it the highest conservation priority of the entire pool analyzed. Our findings identify gaps in the current protected area network and highlight key areas in need of conservation policies and strategies, both in situ and ex situ, to protect the endemic plants of Argentina.
... First, it could convince stakeholders about the national genebank investment as insurance for the country as a responsible action for the future (Gepts 2006;Perrings 1995). Second, these economic evaluations could help understand other cost-effective methodologies for long-germ conservation for certain PGRFA (i.e., cryopreservation instead of in-field conservation) (Pence et al. 2020;Li and Pritchard 2009). Finally, it would help place the ex situ conservation and national germplasm bank research as a fundamental investment in the bioeconomy grants currently promoted by the Science Ministry research goals (Marqueź et al. 2020;Hanley and Perrings 2019). ...
Unlabelled:
Germplasm banks are the most significant repository for plant genetic resources for food and agriculture (PGRFA) worldwide. Despite their strategic importance, national germplasm banks of tropical megadiverse developing countries such as Colombia have extremely limited funds. Therefore, making strategic decisions about research investment is essential. Here, we designed a data-driven approach to build an index that sorts Colombian PGRFA into three groups: high, medium, or low priority, based on four pillars of information from open-access databases and aligned with the sustainable goals of no poverty and zero hunger: Geographic origin, vulnerability status, economic benefits, and food security importance. We analyzed 345 PGRFA using the index, separating them into two groups, 275 already conserved in the Colombian germplasm bank (BGVCOL group) and 70 not currently conserved in the BGVCOL (NCB group). We used fuzzy logic to classify each PGRFA by each pillar and integrate it to obtain a priority index. Missing data for native crops were frequent in the BGVCOL group. Therefore we adopted an imputation strategy to fill the gaps and calculated the uncertainty. After applying the index, PGRFA with higher priority were 24 (8.72%) from the BGVCOL (i.e., 15 potatoes, three tomatoes, two tree tomatoes, pineapple, cocoa, papaya, and yacon) and one from NCB (i.e., coffee). We concluded that this methodology successfully prioritized PGRFA in Colombia and shows the big holes of knowledge for future research and alternatives to improve this index. The versatility of this methodology could be helpful in other genebanks with budget limitations for research investment.
Supplementary information:
The online version contains supplementary material available at 10.1007/s10531-023-02599-7.
... And so, implementing conservation action for such listed species (viz Kleinia venteri) is urgent. Li and Pritchard (2009) stated that storing seeds is one of the main means of ex-situ conservation for flowering and seeds. ...
The need to conduct a detailed biological and ecological study on Kleinia venteri was sparked by the drastic small population sizes of this endemic species in the Polokwane area of the Limpopo Province, and the perceived anthropogenic threat to it. The aim of the study was to investigate population numbers and anthropogenic impacts of three populations of K. venteri in Fauna Park and Sterpark, Polokwane. This was done in order to provide baseline data that ultimately could be used to develop an informed management and monitoring plan for the populations of this small endemic species. The study was carried out in three public parks situated in the suburban residential areas of Fauna Park (two populations) and Sterpark (one population). Due to the small size of these parks, each population was treated as one quadrat. The following parameters were documented via a field datasheet: population size (surface area), number of individuals per population and density, as well as the anthropogenic and/or abiotic threat. Results showed that there were 38 plants in the Fauna Park population and 52 in the Sterpark population. However, the exact number of individuals per population might be slightly higher as plants were difficult to detect without leaves, showing only very short stems and flower buds, which was a consequence of late seasonal rains in the area. The species occur in a relatively small area. The Fauna Park population occur over approximately 200 m 2 , while the Sterpark population area is found in a small area of roughly 150 m 2. Thus the overall density of the Fauna Park population was around five plants/m 2 , and at Sterpark approximately three plants/m 2. With regards to the anthropogenic threats in the study area, the study found that due to the fact that plants occur in recreational/public parks and next to main roads, they are subject to trampling and litter by visitors, decapitation by the municipality during grass cutting, and toxic vehicle exhaust fumes (exhaust fumes contain certain poisonous chemicals, including carbon monoxide, sulphur dioxide, nitrogen oxides, formaldehyde, benzene and soot), which can be detrimental to plant life. It is concluded that the species is under great stress in the areas where it occurs, and thus urgent adaptive conservation is necessary for this small endemic species. 2
... While seeds are the primary collection for herbaceous plants, woody perennial crops rely heavily on living collections because their longer life history cycles and different seed characteristics (e.g., larger, heavier, fleshier) preclude many of these cultivars from relying on seed-based genetic banks (Migicovsky et al. 2019). This is particularly true for tropical fruits whose fleshy fruits with high moisture content prevent seed storage and transport through conventional cold dry storage methods (Bonner 1990;Tweddle et al. 2003, Li and Pritchard 2009, Walters et al. 2013. Living collections of woody perennial crops although expensive to maintain, important opportunities to conduct biological research to support conservation and management of agricultural diversity (Migicovsky et al. 2019). ...
Germplasm in the form of living collections can make important contributions to the understanding of how processes that occur at the pollination stage influence reproduction and plant yields. Using artificial pollination experiments this study evaluated the degree of self-compatibility, dependence of their reproductive systems on flower visitors to set fruit and potential effect of pollen type (self vs cross vs open pollination) of four commercial cultivars ('Julie', 'Keitt', 'Kent' and 'Tommy Atkins') at the Juana Díaz Experimental Station (JDES) in Puerto Rico. Open natural pollinations tended to produce more fruit and yielded seeds with faster development times than artificial pollinations in three of the four cultivars ('Julie', 'Tommy Atkins' and 'Keitt'). Also resulted in faster seed germination in two cultivars ('Julie' and 'Tommy Atkins'). The combined results may suggest that not only animal mediated pollination is needed for these cultivars but that this mode of pollination also results in improved yields, fruit, and seed traits. The importance of studying the breeding system of all living germplasm and for M. indica, a fruit crop with variable breeding systems throughout its distribution results reiterate the importance of local pollinators and the need to evaluate the circumstances by which pollen donors may influence fruit characteristics in this crop.
... Anna Mikuła, Damian Makowski, Christina Walters, and Jan J. Rybczyński (Schulte and Reski 2004;) and cost-effective conservation (Li and Pritchard 2009) will require integration of in vitro techniques with cryopreservation practices (Engelmann 2004;Sarasan et al. 2006;Pence et al. 2007;Keller et al. 2008). Cryopreservation methods for gametophytes of mosses (Christianson 1998;Pence 1998;Burch and Wilkinson 2002;Burch 2003;Schulte and Reski 2004;Rowntree et al. 2007;Rowntree and Ramsay 2009) and liverworts (Pence 1998;Rowntree and Ramsay 2009) appear to be established, but successful cryopreservation of fern gametophytes is reported in only seven species: Davallia fejeensis, Drynaria quercifolia, Cibotium glaucum, Adiantum trapeziforme, Adiantum tenerum, Polypodium aureum (Pence 2000a), and Cyathea australis ). ...
... The Heavy metals uptake was examined in various parts of Himalayan Alder. The accumulation of metals in different part were previously observed by other scientists as [18][19][20]. The [21] recorded excellent accumulation of metals in roots of the Alnus nepalensis. ...
The excess amount of heavy metal in soil pose a serious risk for the life and food chain of living beings. The recommended and feasible procedure to combat heavy metal is plantation of trees with excellent capacity of accumulation. Alnus nitida is a plant species grown on the banks of rivers and streams in western Himalayas and Hindu Kush region of the Sino-Japanese belt. It plays a significant role in accumulation of heavy metals from water. In current study it was explored in the west from Bajaur to Kashmir in the east. For heavy metals analysis shoot, leaves Root and Bark of Alnus nitida were washed thoroughly under tap water and then placed in an 81 °C oven to dry it for about 5 minutes. After acid digestion plant material were put in falcon tube to raise the level of sample to 40 ml through distilled water. The accumulation of heavy metal in Himalayan alder was assessed via atomic absorption spectroscopy. The Heavy Metals analyses were carried out to find the bioaccumulation ability of Alder by using standard formulas of bio concentration factor (BCF), Translocation Factor (TF) and Biological Accumulation Coefficient (BAC). It was observed an efficient accumulator of all the heavy metals as revealed by the values of BCF in shoots, BCF in roots and also the TF. Himalayan Alder has greatly declined through out in its habitat as a result of drought, developmental projects, deforestation and other anthropogenic activities. Current study can provide a baseline for further comprehensive studies heavy metals studies of other such species.
... In the United States, the NCGRP (USDA-National Centre for Genetic Resource Preservation) conserves pollen of 13 pear cultivars and 24 Pyrus species [62]. In China, pollen of over 700 accessions of traditional Chinese flower species is conserved under cryopreservation [63]. ...
Cryopreservation is one of the most promising techniques applied for the long-term conservation of various plant genetic resources ex situ. Tremendous progress has been made in this field for the last 30–40 years. Cryobanks have been established in various parts of the world as a strategy to conserve difficult-to-conserve species. Currently, it is estimated that over 10,000 accessions of vegetatively propagated crops starting from in vitro cultures are safely conserved for the long term through cryopreservation. Pollen cryopreservation is considered to be a complementary conservation strategy for crop species, and tremendous progress has been made in this area in the last few years. Pollen conservation promotes improved efficiency in breeding programs and germplasm conservation and exchange in the case of clonally propagated crops. In this chapter, we try to chart out the history of plant cryopreservation and how it has evolved as a technique and how it is applied for pollen conservation.
The high incidence of oro-dental pathologies correlated with the significant increase in antibiotic resistance has led to the urgent need to develop alternative treatments, using as natural sources the active principles present in medicinal plants. Thus, at the border between traditional and modern, the use of therapeutic effects of various medicinal plants seems to be a way of preventing and treating oro-dental diseases. Along with this use of plant resources, there is therefore also an awareness of the need to conserve species affected, over time, by overharvesting or even mass extinctions. The sustainable use of these resources leads to maintaining the dynamic balance of ecosystems, maintaining and preserving ecosystem services vital to the development of life on Earth.
Plant cryobanks play a significant role in modern science and breeding. They contribute to the recovery of lost species, the emergence of new plant varieties, and help preserve and explore the diversity of the plant world. The IPPRAS Cryobank collection is constantly supplemented with new samples, while, at the same time, the stored samples are being monitored. In order to test seed germination, seeds of Allium and Veratrum species were thawed. Rare Allium species seeds, such as A. nutans, A. schoenoprasum, and A. victorialis were stored in liquid nitrogen for 17, 19, and 30 years, respectively. Long-term cryopreservation decreased germination rates for A. nutans from 96.55 to 50.00%, for A. schoenoprasum from 72.00 to 62.75%, and for A. victorialis from 90.00 to 83.05%. Seeds of a rare medicinal species, Veratrum lobelianum, were stored in liquid nitrogen for 18 years; the seed germination rate during this storage period has been significantly decreased from 75.00 to 14.81%. V. nigrum seeds were also collected and frozen in liquid nitrogen for 3 days. Short-term cryopreservation did not result in a statistically significant change in germination rates (from 79.71 to 82.69%). The seeds of an endangered ornamental species, Cypripedium calceolus, were collected and kept frozen for 3 days. After cryopreservation, the seeds were planted on three different media, as follows: ½ MS, MS with 10% coconut milk, and BM1. On ½ MS medium, 24.98% seeds formed protocorms, while on MS medium with 10% coconut milk, this number was 10.02%, and on BM1 medium, it was 15.02%, respectively; however, after 2.5 months, all of the protocorms died. Thus, it appears that the existing protocol for seed cryopreservation of C. calceolus needs further improvement. The size, weight, and free water content (WC) of six previously cryopreserved Stipa species and three Allium species were measured. For all the Allium and Stipa species studied, we found no correlation between seed size, WC, and cryotolerance. We also found no correlation between the life form, which reflects the water requirement of the species, and cryotolerance.
The main biodiversity crises of the new current millennium are extinction and species introduction. A species may be critically endangered and ultimately extinct when death rates exceed birth for a prolonged duration. The reasons may be either natural or anthropogenic. Nowadays, anthropogenic factors are prominent and cause the extinction of many species in the wild. To prevent the present problem conservation can be possible only through ex-situ methods. In the present study, six highly threatened species were selected for improving macro propagation techniques by using different seed germination methods. Seed germination response was best on by using mature soaked and scarified seeds. The preferable nutrient medium is a 1:1:1:1:1 ratio of red soil, black soil, cocopeat, sand and vermicompost. Through this study, we recorded good germination percentages with Boswellia ovalifoliolata 79%, Croton scabiosus 76%, Hildegardia populifolia 73%, Pterocarpus santalinus 71%, Shorea tumbuggaia 66%, Syzygium alternifolium 69%. These propagation methods are low cost and effectively worked and can be possible for restoration of species in their natural habitats through ex-situ conservation and to avoid the species extinction in the wild.
The vast pool of biodiversity and genetic variation among plant species and its indubitable role in selection and crop improvement have prompted a lot of attention towards various conservation approaches to preserve plant genetic resources (PGR). The key emphasis in such conservation strategies is identifying genetic diversity and devising suitable conservation measures for the benefit of present and future generations. The large-scale adoption of high-yielding varieties of crop plants gradually caused the depletion of genetic variability among wild varieties of plant species. A large reservoir of genetic resources can help in identifying the best gene pool for favourable characteristics like biotic and abiotic stress tolerance during crop improvement and genetic modifications. These factors demand the identification of proper conservation approaches for plant genetic resources. International efforts for conservation have been going on since the 1970s and now, the advent of new technologies and tools opened wider possibilities for the conservation of PGR. This chapter will discuss various efforts made in plant genetic resources conservation such as in situ and ex situ methods and the role of biotechnology in the conservation and management of PGR like cryopreservation and in vitro approaches.
Brazil is a continental dimension country that is the world’s fifth largest country by area and has a broadly diversified climate. For these reasons, Brazil is a megadiverse country and is extremely rich in plants, animals, and microorganisms, which provide conditions to cultivate a diversity of crops, from temperate to tropical climate species, that mainly originated from other countries. Thus, Brazil has a remarkable role in plant genetic resource (PGR) conservation, including both ex situ and in situ strategies. The efficient use of genetic resources allowed plant breeding programs to develop varieties adapted to country conditions, and in association with agronomic practices, this has led Brazil to build a competent tropical agricultural system that provides a significant proportion of the food consumed globally. Several institutions (universities, research centers), nongovernmental organizations (NGOs), farmers, indigenous peoples, and local communities conserve several crop species, their wild relatives, landraces, and other plant species with social and economic potential. In this chapter, we present a summary of the main activities conducted by different Brazilian institutions to ensure the conservation, evaluation, characterization, documentation, and use of plant genetic resources, as well as initiatives and policies aimed at respecting, preserving, and maintaining associated indigenous and local knowledge.
The use of indigenous medicinal plants is still prevalent as the most trusted form of health care, predominantly in developing countries. Overuse of medicinal plant resources, coupled with the negative impacts of unpredictable rainfall and rising temperatures, necessitated the development of local methods to conserve medicinal plants. These indigenous conservation methods have proved to be failing and aggravating threats to medicinal plants. This study aimed to review the alternative conservation and management methods to protect medicinal plants in South Africa. A review of the literature presents in situ, ex situ, natural reserves, wild nurseries, botanical gardens, and seed banks as alternative conservation methods proposed and used by scientists to conserve and manage medicinal plant species. These methods are Western practices introduced to the local communities in an effort to conserve and protect the indigenous medicinal plant species for future use and as a cultural heritage. From a qualitative standpoint, this study adopted the interpretivist research design to offer support to employ the systematic review method. Seminal studies on this subject were purposively collected using keywords extracted from the research topic. The collected data was analysed using the inductive Textual Content Analysis (TCA) method. The results of this study reveal that there are various conservation methods that are implemented as strategies to safeguard the existing medicinal plants, and this proves if these methods are implemented correctly these plants will still be available for future use. It is concluded and recommended that the demand for medicinal plants imposes huge threats to their anticipated availabilities, therefore, the relevant stakeholders need to take urgent corrective measures concerned parties should be consistently exposed to improved resources, advanced training and better education about the benefits and importance of these plants. Keywords: Medicinal plants, conservation method, In situ, natural resource
Medicinal plants are valuable resources for drugs, and the major population in developing countries depends on herbal drugs. Increasing demands on the use of medicinal plants as primary therapeutics put pressure on the conservation strategies of wild medicinal plants. The north-eastern region is considered a reservoir of many medicinal plants accounting for approximately half of the available medicinal plants in India. Many medicinal plant species are endemic to this region, and many growing in the wild are left unaware, so there is a need for identification and conservation. National policy needs to be framed and implemented to conserve the population of medicinal plant species. In this modern world, it is essential to adopt both ex situ and in situ methods as complementary techniques for the conservation of the medicinal plant population.KeywordsConservationMedicinal plantsNorth-eastern regionWildHerbal drugs
Plants are fundamental to directly or indirectly addressing most of humanity’s contemporary challenges such as food scarcity and insecurity, availability of shelter, energy, and industrial raw materials as well as human and environmental health issues and mitigating climate change. However, around 40% of documented plant species are threatened with extinction due to anthropogenic pressure, especially from exponential population growth, overexploitation and mismanagement, habitat loss, modification and fragmentation, introduced alien species, pollution, and novel diseases. Plant diversity and their sustainable conservation and utilization underpin globalization and sustainable development as well as greater options for human innovation and adaptation. Plant conservation approaches are mainly either in situ or ex situ and they may be complementary to each other. Other little-known plant conservation approaches are linked to or derived from in situ and ex situ plant conservation and includes inter situ, quasi in situ, and circa situm plant conservation approaches. This chapter focuses on ex situ plant conservation. Ex situ plant conservation wholly seeks to sustain options for human innovation and adaptation by preserving plant species and taxa outside their native and historic range through the utilization of different techniques and conservation approaches, such as seed and gene banking, cryopreservation, gardens, and arboreta. However, certain factors tend to hinder or disrupt ex situ conservation techniques, including disease outbreaks, unstable weather and climatic conditions required for a variety of plant species, limited genetic diversity, plant stress from reintroduction and poor ex situ infrastructure, and inefficient management systems. For instance, Zingiber species held in field gene banks are known to be affected by soil-borne diseases caused by the bacteria Ralstonia solacearum which can spread further by sticking to human hands. Other examples of disease outbreaks under ex situ plant conservation include Bogia coconut Syndrome’, cassava viral diseases, and Alomoa-bobone viral disease of taro (Colocasia esculenta). This chapter seeks to highlight the potential and actual impacts of disease outbreaks under ex situ conservation using some examples. This chapter outlines how some of these diseases among and within plant species maintained in ex situ conservation can be prevented and/or managed optimally through various effective management strategies as well as the roles of different stakeholders involved in plant germplasm management.KeywordsPlant disease managementDisease outbreakPlant conservationEx-situ conservationPlant diversityGermplasm management
Without knowledge of seed germination requirements, conservation seed bank collections cannot be utilised, nor their viability monitored over time. When germination is low, deciding whether to invest further seed, time and resources into investigating why can be difficult. We investigated the germinability of 37 grassy ecosystem seed bank collections, including germination response to fire-related cues. Where germination was < 75% we investigated seed viability using the tetrazolium chloride (TZ) staining test. Germination and TZ test results were then compared to determine next steps in collection management. Using 95% confidence intervals of the difference between germination and viability, the 37 collections were assigned to one of seven different data-informed management decisions. This approach provides a detailed decision support framework for conservation collection management, to strengthen current guidelines and ensure that time and resources are effectively allocated. Other seed banks could customise this approach depending on the number of seeds used in testing and what percentage of germination is considered sufficient.
The development of the viability equations from the 1960s onwards has underpinned the ex
situ conservation of plant genetic resources as seeds, i.e., seed banking.The equations include
constants that explain the empirical effects of both moisture content and temperature on
longevity.The temperature constants appear to be universal, over the range c. -13°C to 90°C,
whilst the moisture content-related terms are species-dependent. The generation of the full
viability constants requires considerable experimentation and germplasm, but there are short
cuts to a rapid estimation of longevity. Early studies focussed on crop species, however seed
viability constants are now available for at least 66 species from 26 families. Empirical data
reveal low-moisture-content limits to the response of seed longevity to hydration, generally at
moisture contents in equilibrium with c. 15% RH at 15°C. Below this level of hydration,
longevity may increase slightly, remain the same or decrease slightly, depending on the seed lot.
This point appears to be below the moisture content at which seeds are thought to enter the
‘glassy’ state, indicating that removal of water from the glass may not destabilise the seeds, at
least over shorter experiments. In addition, there is some evidence that this low moisture
content limit varies with both seed chemical composition and storage temperature. A similar
limitation applies to the effects of low temperatures; although there is little long-term data
available, the sub-zero temperature response appears not to fit the quadratic term appropriate
for higher temperatures.These qualifications to the seed viability equations have contributed
to the recent debate about the validity of predicting, by extrapolation, longevities in the region
of millennia for dry, cold-stored seeds. By comparison, practical evidence on buried seeds
supports the notion of seed germination after storage for centuries.
The science of reintroduction for conservation purposes is young, and there is still much to learn about the practice. As a means to achieving biological goals of successfully establishing new populations to enhance a species survival prospects, and project goals, such as learning how to go about establishing new populations, reintroduction projects are best done as well designed scientific experiments that test explicit hypotheses. Focusing on a range of factors common to any reintroduction, we review several empirical reintroduction projects with respect to hypotheses tested, experimental materials and methods employed, and evaluate their success in both biological and project terms.
Plant species that are vegetatively propagated, that have long life
cycles and/or produce nonorthodox seeds are traditionally
maintained in field collections. Maintaining plants in the field is
costly and carries high risks of loss; therefore, the strategies and
procedures employed to establish and maintain field collections
need to be practical, rational and economic, in addition to being
scientifically sound. Experience in cost-effective management of
field collections lies with individual curators and is not readily
available to guide others. Further, there are increasing opportunities
for using in vitro methods for the conservation of crops normally
conserved in the field, and there is a need to develop strategies and
procedures for managing in vitro collections as routine and integral
part of the overall conservation strategy of a crop genepool or
collection.
The International Plant Genetic Resources Institute (IPGRI), on
behalf of the System-wide Genetic Resources Programme (SGRP),
with the Food and Agriculture Organization of the United Nations
(FAO) and the International Centre of Tropical Agriculture (CIAT),
organized in 1996 a technical consultation meeting held at CIAT,
Cali, Colombia, to examine the role of field and in vitro germplasm
collections in strategies to conserve and use clonally propagated
crops, problems and constraints in their management, and the
complementarity of field and in vitro germplasm collections. One of
the recommendations of the meeting was to develop general
guidelines for the management of field and in vitro germplasm
collections, which should identify key issues and provide genebank
managers with decision criteria and options in establishing,
maintaining and using field and in vitro germplasm collections.
The first draft of these Guidelines has been produced by Dr Barbara
M. Reed, Plant Physiologist at the USDA/ARS National Clonal
Germplasm Repository, Corvallis, Oregon (USA). It has been further
developed and updated by a consultant, and several IPGRI staff
members have provided significant input to this document.
These Guidelines are divided into two main sections. The first
section presents general considerations for the establishment and
management of germplasm collections. The topics addressed
concern the establishment of the collection, the acquisition and
entry of plants into the collection, germplasm health issues, a
presentation of the various conservation methods available to
germplasm collections and collection management procedures.
The second section focuses on the procedures for the
establishment and maintenance of field and in vitro collections,which are dealt with in two subsections. The first subsection, which
concerns field collections, presents and discusses procedures for
establishing and maintaining vigorous and healthy plants, for
maintaining the security of the collections and for distributing plant
germplasm. Finally, research needs related to the management of
field collections are identified. The second subsection deals with in
vitro collections. The laboratory and storage facilities required for
the establishment and maintenance of in vitro collections are
presented and the need for the establishment of detailed standard
operational procedures is highlighted. In vitro culture and
conservation procedures are then presented and analyzed,
including the establishment of a tissue culture system, the
introduction of plant material in vitro, slow-growth storage,
cryopreservation and distribution of plant material. Finally, research
needs are identified aiming at improving in vitro conservation of
plant germplasm collections.
Boxes are included throughout the document to illustrate the
various points addressed in the text through concrete examples of
procedures developed by genebank curators, or to provide detailed
information on specific subjects. Similarly, 13 appendixes are
provided as examples of documents employed in the management
of field and in vitro collections (e.g. record-keeping systems for field
and in vitro collections) and of particular procedures (e.g. detection
of contaminants in in vitro cultures).
It is hoped that these Guidelines will contribute to improving the
conservation of vegetatively propagated crops through a more
rational, complementary and cost-effective use of field and in vitro
conservation techniques.
Taxus wallichiana var. mairei (Lemee & Leveille) L. K. Fu & Nan Li is a highly endangered conifer in China. It is dioecious and wind pollinated, with seed dispersal by animals. Extant natural populations on mainland China and Taiwan are highly scattered, largely as a result of habitat loss and overexploitation. Intersimple sequence repeat (ISSR) markers were employed to assess the genetic structure among 464 individuals from 17 populations across the variety's distribution range in the Sino-Japanese and Malesian floristic subkingdoms. ISSRs revealed a high genetic diversity (percentage of polymorphic loci = 98.4%, Nei's gene diversity = 0.3467, Shannon's information index = 0.5152) at the species level and high differentiation among populations (coefficient of gene differentiation = 0.4066; theta(B) = 0.4376). Gene flow among populations was found to be limited to the mainland populations. A UPGMA (unweighted pair group method with arithmetic mean) dendrogram suggests that the population in Taiwan is genetically the most isolated, while among the mainland populations a trend of an east-west split is suggested. This finding is supported by the analysis of molecular variance. The pattern of genetic variation suggests that the extant distribution of T. wallichiana var. mairei is the result of the fragmentation of a historically more continuous distribution. Conservation measures for this highly endangered plant are discussed, and an integrated approach to increase plant density and connectivity among the remaining populations is suggested.
Final germination percentages of 25 accessions of Brassicaceae from the UPM (Universidad Politécnica de Madrid) seed bank were evaluated after 38–40 years of storage. The seeds were preserved at temperatures between −5°C and −10°C in flame sealed vials
containing dehydrated (blue) silica gel. Seed moisture content ranged between 0.3 and 3% (f.w.b) after storage. Most accessions (ten out of twelve) with high initial (before storage) germination rate (low initial dormancy) maintained these high values almost intact after storage (91–100%
germination). In two accessions, seeds had developed a secondary dormancy, which was successfully overcome by scarification. A second set of 13 accessions had low initial germination rates (0–20%, i.e. high initial dormancy). In one accession, dormancy had been broken during storage
(92% germination) and in nine accessions germination was significantly enhanced by GA3 and or scarification. Seed dormancy most often decreases during storage but it may also increase or remain unchanged. The consideration of these dormancy variations is very important when evaluating
seed longevity in wild species. The preservation method based on silica gel and low temperature (−5°C and −10°C) has proved highly efficient at least for Brassicaceae. Vials with seeds of 12 additional accesssions had remained at room temperature during 34-39 years and
those seeds showed germination percentages that were similar to those preserved in the cold room. This result suggests that temperature might not be as important as expected – at least for medium-term preservation – and supports the possibility of using ultra-dry methods.
We used cross‐species and phylogenetic analyses to compare seed traits of 36 species with desiccation‐sensitive and 189 with desiccation‐tolerant seeds from a semi‐deciduous forest in Panamá.
When correcting for phylogenetic dependence between taxa, the desiccation‐sensitive seeds were significantly larger than desiccation‐tolerant seeds (3383 vs 283 mg) and typically shed during the wet (as opposed to dry) season. Both traits presumably reduce the rate of seed drying and hence the risk of desiccation‐induced mortality for the desiccation‐sensitive species.
Growing‐house germination trials in simulated understorey and canopy gap environments revealed that the desiccation‐sensitive species germinated most rapidly. Additionally, on a proportion basis, the desiccation‐sensitive seeds allocated significantly less resources to seed physical defences (endocarp and/or testa) which may partially facilitate rapid germination. Both relationships were significant when correcting for phylogenetic dependence and seed mass.
Our results suggest that, for large‐seeded species which will dry slowly, desiccation sensitivity may be advantageous. Rapid germination may reduce the duration of seed exposure to predation, and the low investment in physical defence means that, per unit mass, desiccation‐sensitive seeds are a more efficient use of resources in seed provisioning.
Populations of a threatened aquatic plant, Nymphoides peltata, have rapidly degenerated under the influence of recent artificial changes in Lake Kasumigaura of Japan. To estimate the potential of soil seed banks for genetic restoration of the species, we used 10 microsatellite markers to analyze the genetic variation in adults and in seedlings that emerged from soil seed banks. About 187 leaf samples from the cultured stocks that were collected in 17 adult subpopulations in 1995 and 2000 and from three subpopulations that were newly discovered in 2002 were analyzed. As a result, only 18 genets could be identified, suggesting that clonal diversity of the adult population had already become extremely low. Genetic tests were performed on 430 seedlings from seed banks at six locations of natural lakeshores and three of the restoration sites that were artificially constructed in an attempt to assign them to the remnant adult population; many of the seedlings showed genetic variation different from the adults. Furthermore, the seedlings preserved seven alleles that had been lost from remnant adults. However, they had lower average numbers of alleles and heterozygosity levels (NA = 1.5–3.1, H
E = 0.146–0.487) than the remnant adults (NA = 3.5, H
E = 0.539) and showed high inbreeding coefficients, suggesting that the seed banks were produced by inbreeding. Thus, although the seed banks had a certain potential to restore genetic diversity, the fitness reduction in seed banks caused by inbreeding could affect the success of restoration based on seed banks.
Cryopreservation of a core collection of 444 elm (Ulmus spp.) clones in liquid nitrogen was carried out by two laboratories participating in a European project of conservation of elm genetic resources. Plant material, collected in nine European countries, represented a large sample of the genetic diversity within three European elm species and their hybrids. The cryopreservation technique used in both laboratories involved the stepwise freezing of cryotubes containing dormant buds. Comparisons with fresh buds showed that the cryopreservation treatment had no negative effect on the viability and regrowth potential of frozen buds. Tests on a random sample of 26 clones showed that direct regrowth of cryopreserved buds (i.e., through propagation by microcuttings) of Ulmus minor and Ulmus laevis was possible; conversely, Ulmus glabra could only be regrown through micrografting. Most thawed explants from all 26 clones survived through the whole cultivation phase and were successfully transferred to the field. A calculation of costs indicates that cryopreservation of elm buds is economically competitive to field clonal archives.
We tested the effect of high temperature treatment (103 °C for 17 h) on seed survival for 26, 6 and 5 species in the Aizoaceae, Crassulaceae and Cactaceae, respectively. For both the Aizoaceae and Cactaceae species there was a significant positive correlation between the proportion of seeds surviving and the absolute maximum annual air temperature at the collection site. These results suggest that tolerance of extreme temperatures may have evolved as a mechanism to enable persistence in the soil in these predominantly desert species. Furthermore, these species may provide a useful model system for investigating the mechanism(s) of both desiccation- and thermo-tolerance in seeds.
Nine seedlots of the widely planted southern and central European native tree species Acer pseudoplatanus L. were collected along a north–south gradient spanning 21° of latitude in Europe. We investigated how the heat sum during seed development influences seed maturity as assessed by physical, physiological and biochemical traits. Using principal component analysis we found predictable and consistent patterns in all traits, which correlated with heat sum. For example, compared with fruits from their native range (Italy and France, heat sum >3000°C d), fruits from the coldest location (Scotland; heat sum of 1873°C d) were shorter (c. 30 v. 42 mm), germinated over a narrower temperature range (5–20 v. 5–35°C) and had smaller embryos (28 v. > 70 mg) with a higher water content (c. 63 v. 48%), less negative solute potentials (c. –2.4 v. –4.1 MPa) and were more desiccation sensitive (critical water potential of –20.2 v. –55.4 to –60.7 MPa). The observed level of desiccation-tolerance for the French and Italian seedlots is more consistent with the intermediate category than the previous classification of A. pseudoplatanus as recalcitrant. Our results demonstrate that a lower heat sum causes fruits from northern Europe to be dispersed before maximum potential seed quality is achieved.
In the tropics, species with recalcitrant or desiccation-sensitive, Type III seeds are largely restricted to regions with comparatively high rainfall, because desiccation-induced seed death will be minimal in these environments. However, species with recalcitrant seeds do occur in drylands, although little is known about ecological adaptations to minimize seed death in these environments. Here we present data for the seed desiccation tolerance of 10 African dryland species and examine the relationships between seed size, rainfall at the time of seed shed, and desiccation tolerance for these and a further 70 species from the scientific literature. The combined data set encompasses species from 33 families. Three species (Syzygium cumini, Trichilia emetica, and Vitellaria paradoxa) had desiccation-sensitive seeds, and the remaining seven species investigated were desiccation-tolerant. The desiccation-sensitive species had large (>0.5 g) seeds, germinated rapidly, and had comparatively small investments in seed physical defenses. Furthermore, seed was shed in months of high rainfall (>60 mm). In comparison, for species with desiccation-tolerant seeds, seed mass varied across five orders of magnitude, and seed was shed in wet and dry months. Although infrequent in dryland environments (approximately 11% of the species examined here), species with desiccation-sensitive seeds do occur; large size, rapid germination, and the timing of dispersal all reduce the likelihood of seed drying. Furthermore, desiccation-sensitivity may be advantageous for large-seeded species by increasing the efficiency of resource use in seed provisioning.
Rubber plantations are expanding rapidly throughout montane mainland Southeast Asia ( 1 – 3 ). More than 500,000 ha may have been converted already in the uplands of China, Laos, Thailand, Vietnam, Cambodia, and Myanmar (see the figure, panel A). By 2050, the area of land dedicated to rubber and other diversified farming systems could more than double or triple, largely by replacing lands now occupied by evergreen broadleaf trees and swidden-related secondary vegetation ( 2 ). What are the environmental consequences of this conversion of vast landscapes to rubber?
This multi-author book gives a comprehensive account of desiccation and plant survival, and of how plant cells deal with extreme water stress. There is a general introduction on desiccation, and then four sections dealing with: The technical background to desiccation studies; the frequency and levels of dehydration stress tolerance in biological systems; mechanisms of damage and tolerance; and a brief retrospect and prospect. Orthodox and recalcitrant seeds, pollen and spores, vegetative parts, and other plant tissues are covered in detail.
A 1,288 ± 271-yr-old (1,350 ± 220 yr BP, radiocarbon age) seed of Sacred Lotus (Nelumbo nucifera Gaertn.) from an ancient lake bed at Pulantien, Liaoning Province, China, has been germinated and subsequently radiocarbon dated. This is the oldest demonstrably viable and directly dated seed ever reported, the preserved relict of one of the early crops of lotus cultivated by Buddhists at Pulantien after introduction of the religion into the region prior to 372 A.D. A small portion of the dry pericarp of a second lotus fruit from the same locale has been dated as being 332 ± 135-yr-old (270 ± 60 yr BP, radiocarbon age) by accelerator mass spectroscopy at the Lawrence Livermore National Laboratory. This polycentenarian seed not only germinated but is still growing (since March, 1994). Of six old lotus fruits tested, two-thirds germinated, almost all in fewer than 4 d, as rapidly as fruits harvested from the progeny of Pulantien Sacred Lotus plants (under cultivation by the National Park Service in Washington, DC), and more rapidly than fresh fruits of Yellow Lotus [N. lutea (Willd.) Pers.]. Growth of the old lotus is robust: rhizome formation and leaf emergence at rhizome nodes are more rapid than those of the Pulantien progeny, although the leaf width is smaller. Activity of the protein-repair enzyme L-isoaspartyl methyltransferase in the old lotus seed is persistent during germination and is as robust as that in the progeny, and the degree of aspartyl racemization in proteins of the two groups of plants is minimal and essentially identical. The six dated ancient Sacred Lotus fruits range in age from 95 to 1,288 yr (with a mean age of 595 ± 380 yr), evidently reflecting their production, deposition, and preservation at varying times during the intervening millennium.
The challenge facing the world’s biological and conservation scientists is threefold: to classify the existing biological diversity; to halt the rate of ecosystem, habitat, species and genetic loss; and to feed the ever increasing human population. It is generally agreed that a catastrophic loss of plant genetic diversity is occurring at this moment: species, gene combinations and alleles are being lost for ever and this process of genetic erosion is likely to become even more grave in the future. The conservation of plant diversity is of critical importance, because of the direct benefits to humans that can arise from its exploitation in new agricultural and horticultural crops, the development of medicinal drugs and the pivotal role played by plants in the functioning of all natural ecosystems. The economic, political and social consequences that would result from a steady loss of plant diversity combined with rapid population growth is likely to be devastating if unchecked. The importance of these issues to humankind is underlined in Article 1 of the objectives of the Convention on Biological Diversity (UNCED, 1992):
The objectives of this convention ... are the conservation of biological diversity, the sustainable use of its components and the fair and equitable sharing of the benefits arising out of the utilisation of genetic resources ...
Worldwide, the number of genebanks and the amount of seed stored in them has increased substantially over the past few decades. Most attention is focused on the likely benefits of conservation, but conserving germplasm involves costs whose nature and magnitude are largely unknown. Moreover, these costs place a lower bound on the benefits deemed likely to justify the expense of conserving seed. In this study, we compile and use a set of cost data for wheat (Triticum aestivum L.) and maize (Zea mays L.), stored in the CIMMYT genebank to address a number of questions. The marginal costs of holding an existing accession for one more year are presented, along with the costs of conserving saved seed for the life of the genebank (taken here to be 40 yr), and in perpetuity. We also investigated the scale economies evident in the CIMMYT genebank operation as a basis for assessing the economics of consolidating several genebanks. For accessions known to satisfy viability requirements, it costs just $0.19 and $0.93 to carry over an existing accession of wheat and maize respectively, for one more year; $7.19$ and 30.24 to store an accession of each crop for the life of a genebank, and $10.26 and $58.85 to conserve accessions in perpetuity. Under baseline assumptions about interest rates, capital depreciation, and regeneration regimes, the present value of conserving the existing accessions in perpetuity at CIMMYT is $8.86 million - $3.87 million for storing the 123 000 wheat accessions and $4.99 million for the 17 000 maize samples. Maintaining the current level of effort to distribute accessions free-of-charge to those who request them would cost an additional $5.28 million in perpetuity.
Equations for predicting seed longevity in storage have been improved so that they now take into account variations within a species in initial seed quality-which is affected by genotype and pre-storage environment-and so that they are more accurate over a wider range of storage environments These improvements have been incorporated into a seed viability nomograph for barley (Hordeum distichum L.) which may be used to predict percentage viabihty of any seed lot after any time in any storage environment within the range -20 to 90 °C and 5-25 per cent moisture content. Applications of the improved equations to seed drying and to long-term seed storage for genetic conservation are discussed.
Seeds of six species of Meliaceae were tested for germination following desiccation and subsequent hermetic storage for up to 26 months in different environments. Seeds of both Aglaia clarkii and Sandoricum koetjape were very sensitive to desiccation; no seeds survived desiccation to 20% moisture content or below. In contrast, stones of Melia azedarach survived desiccation to 3.5% moisture content and viability was maintained during 26 months' subsequent hermetic storage in 14 of the 15 environments which combined factorially five stone moisture contents between 3.5 and 11.7% with three temperatures between -20 °C and 10 °C, the exception being that environment which provided the highest moisture content and temperature (i.e. 10 °C with 11.7% moisture content) in which loss in viability was considerable. Seeds of Azadirachta indica tolerated desiccation to moisture contents in equilibrium at 20 °C with 30-55% r.h. depending on seed lot, and a considerable proportion of seeds survived further desiccation to moisture contents in equilibrium with 6.5 to 30% r.h. Seeds of Swietenia macrophylla and Khaya senegalensis were more tolerant of desiccation than those of Azadirachta indica, but some loss in viability was detected on desiccation to moisture contents in equilibrium with 17% r.h. Moreover, the longevity of all three species in hermetic air-dry storage was shorter at cooler (-20 °C and 0 °C) than at warmer (10 °C) temperatures. We conclude that Aglaia clarkii and Sandoricum koetjape show recalcitrant seed storage behaviour, while Melia azedarach shows orthodox seed storage behaviour, but that Azadirachta indica, Khaya senegalensis and Swietenia macrophylla show intermediate seed storage behaviour. We illustrate how combining information on four criteria (seed weight, shape, moisture content at maturity, and plant ecology) may provide a guide to likely seed storage behaviour in Meliaceae.
Between about -350 and -14 MPa the rate of loss of viability in orthodox seeds is a positive function of water potential. The relative effect of water potential has been analysed in an oily seed (lettuce) and a non-oily seed (barley) and found to be more or less identical. The lower limit for the relation in various species coincides with a seed moisture content (wet basis) between about 2 and 6 %. Below this level there is little or no improvement in longevity with reduction in moisture content. The upper limit coincides with moisture contents of between 15 and 28%, depending on whether the seeds are oily or non-oily. A water potential of about -14 MPa is the threshold for respiration which increases more-or-less linearly with increase in water potential above this level. Above this threshold, and providing oxygen is available to sustain respiration, seed longevity increases with increase in water potential except that, unless the seeds are dormant, germination may be initiated at a water potential of about - 1.5 to -0.5 MPa. In the absence of oxygen there may be a slight further decline in longevity with increase in water potential above -14 MPa before longevity reaches a minimum value. Since they cannot be dried very much without immediate loss of viability, recalcitrant seeds survive longest in the presence of oxygen at maximum water potential commensurate with preventing germination. The threshold water potential for immediate loss of viability has not been determined for most species but it is probable that it is close to the water potential typical of the permanent wilting point in these plants, say -2 MPa.
Seed survival data for eight diverse species, namely the cereal barley (Hordeum vulgare L.), the grain legumes chickpea (Cicer arietinum L.), cowpea [Vigna unguiculata (L.) Walp.] and soya bean [Glycine max (L.) Merr.], the timber trees elm (Ulmus carpinifolia Gleditsch.), mahogany (Swietenia humilis Zucc.), and terb (Terminalia brassii Exell.), and the leaf vegetable lettuce (Lactuca saliva L.) were compared over a wide range of storage environments (temperatures from -13 °C to 90 °C, seed moisture contents from 1.8 to 25% f.wt) using a viability equation developed previously. In accordance with that equation, the effect of temperature on seed longevity was dependent upon the temperature range. The temperature coefficients of the viability equation did not differ significantly (P > 0.05) among the eight species despite their contrasting taxonomy. Thus the quantitative relation between seed longevity and temperature does not vary among diverse species. The same conclusion was obtained for the coefficients of a proposed alternative model of the relation between seed longevity and temperature. The implications of the two temperature models in the viability equation for extrapolations to low and very low temperatures are discussed.
A gene bank is an ex situ (or off site) collection of genetic material held for long-term security or for ease of access. The genetic material is usually in the form of live propagules or gametes though, increasingly, pure DNA is held. A bank can also be a collection of full-grown plants representing the diversity of certain species (a field gene bank) or a set of cultures (cell, tissue, embryo, or microorganism). The widest definition might also embrace collections of plants grown primarily for purposes of education and horticulture in botanic gardens and animals represented in zoological gardens or parks.
Though cryogenic storage is presumed to provide nearly infinite longevity to cells, the actual shelf life achieved under ultra-cold temperatures has not been addressed theoretically or empirically. Here, we report measurable changes in germination of dried seeds stored under liquid nitrogen conditions for >10 years. There was considerable variability in the extent of deterioration among species and accessions within a species. Aging time courses for lettuce seeds stored at temperatures between 50 and −196 °C were fit to a form of the Avrami equation to determine rate coefficients and predict half-life of accessions. A reduction in the temperature dependency on aging rate, determined as a break in the Arrhenius plot, occurred at about −15 °C, and this resulted in faster deterioration than anticipated from extrapolation of kinetics measured at higher temperatures. The break in Arrhenius behavior occurred at temperatures in between the glass transition temperature (28 °C) and the Kauzmann temperature (−42 °C) and also coincided with a major triacylglycerol phase change (−40 to −7 °C). In spite of the faster than anticipated deterioration, cryogenic storage clearly prolonged shelf life of lettuce seeds with half-lives projected as ∼500 and ∼3400 years for fresh lettuce seeds stored in the vapor and liquid phases of liquid nitrogen, respectively. The benefit of low temperature storage (−18 or −135 °C) on seed longevity was progressively lost if seeds were first stored at 5 °C. Collectively, these results demonstrate that lowering storage temperature progressively increases longevity of seeds. However, cryogenic temperatures were not sufficient to stop deterioration, especially if initial stages of aging were allowed to progress at higher storage temperatures. This work contributes to reliable assessments of the potential benefit and cost of different genebanking strategies.
Cryopreservation is the storage of viable cells, tissues, organs and organisms at ultra-low temperatures, usually in liquid nitrogen to a minimum temperature of -196°C. The term, phytodiversity describes an assemblage of plants, algae and cyanobacteria; it is used to encourage a more holistic approach to cryopreserving the photosynthetic primary producers. In anticipation that encouraging exchange of knowledge across the different phytodiversity sectors sharing many common goals will facilitate their overall cryobanking activities. The main objective of the review is to explore the boundary between cryobiology theory and cryobanking practice. Natural adaptations will be considered with respect to cryopreservation protocol development and this theme includes a brief examination of 'cold' omics research. In addressing the problem of cryostorage recalcitrance, the review compares and contrasts phytodiversity from the perspective of environmental adaptation. A substantial part of the content is dedicated to appraising risk and safety issues and the microbial and pathological aspects of cryobanking. The importance of best practices for safeguarding the security of phytodiversity held in cryobanks is also considered. The review concludes by prospecting the use of the medical translational research paradigm in cryobanking.
ABSTRACT Comprising a land area of ca. 90,000 km,, less than one twentieth (5%) the land area of the southern African subcontinent, the Cape Floristic Region (CFR) is, for its size, one of the world’s richest areas of plant species diversity. A new synoptic flora for the Region has made possible an accurate reassessment of the flora, which has an estimated 9030 vascular plant species (68.7% endemic), of which 8920 species are flowering plants (69.5% endemic). The number of species packed,into so small an area is remarkable,for the temperate,zone and compares,favorably with species richness for areas of similar size in the wet tropics. The Cape region consists of a mosaic,of sandstone,and shale substrata with local areas of limestone. It has a highly dissected, rugged topography, and a diversity of climates with rainfall mostly falling in the winter months and varying from 2000 mm,locally to less than 100 mm. Ecological gradients are steep as a result of abrupt differences in soil, altitude, aspect, and precipitation. These factors combine to form an unusually large number of local habitats for plants. Sandstone-derived soils have characteristically low nutrient status, and many plants present on such soils have low seed dispersal capabilities, a factor promoting localized distributions. An unusual family composition includes Iridaceae, Aizoaceae, Ericaceae, Scrophulariaceae, Proteaceae, Restionaceae, Rutaceae, and Orchidaceae among the 10 largest families in the flora, following Asteraceae and Fabaceae, as the most speciose families. Disproportionate radiation has resulted in over 59.2% species falling in the 10 largest families and 77.4% in the largest 20 families. Twelve genera have more than 100 species and the 20 largest genera contribute some 31% of the total species. Species richness of the Cape flora is hypothesized to be the result of geographic and parapatric radiation in an area with a mosaic of different habitats due to local soil, climate, and altitudinal differences that combine,to produce steep ecological gradients. Also contributing to the diversity has been a relatively stable geological history since the end of the Miocene that saw the establishment,of a semi-arid and extreme seasonal climate at the southwestern,part of southern Africa. Key words: floristics, Mediterranean-type climate, phytogeography, plant diversity, southern Africa, speciation. Situated at the southwestern tip of the African
A new 9,11-secosteroid, stellettasterol (1) was isolated from a Japanese marine sponge,Stelletta sp.; its structure was determined by spectroscopic analysis. All NMR signals of1 were unambiguously assigned by application of various 2D NMR techniques. Stellettasterol exhibited antifungal activity againstMortieralla ramannianus.
A 1,288 +/- 271-yr-old (1,350 +/- 220 yr BP, radiocarbon age) seed of Sacred Lotus (Nelumbo nucifera Gaertn.) from an ancient lake bed at Pulantien, Liaoning Province, China, has been germinated and subsequently radiocarbon dated. This is the oldest demonstrably viable and directly dated seed ever reported, the preserved relict of one of the early crops of lotus cultivated by Buddhists at Pulantien after introduction of the religion into the region prior to 372 A.D. A small portion of the dry pericarp of a second lotus fruit from the same locale has been dated as being 332 +/- 135-yr-old (270 +/- 60 yr BP, radiocarbon age) by accelerator mass spectroscopy at the Lawrence Livermore National Laboratory. This polycentenarian seed not only germinated but is still growing (since March, 1994). Of six old lotus fruits tested, two-thirds germinated, almost all in fewer than 4 d, as rapidly as fruits harvested from the progeny of Pulantien Sacred Lotus plants (under cultivation by the National Park Service in Washington, DC), and more rapidly than fresh fruits of Yellow Lotus [N. lutea (Willd.) Pers.]. Growth of the old lotus is robust: rhizome formation and leaf emergence at rhizome nodes are more rapid than those of the Pulantien progeny, although the leaf width is smaller. Activity of the protein-repair enzyme L-isoaspartyl methyltransferase in the old lotus seed is persistent during germination and is as robust as that in the progeny, and the degree of aspartyl racemization in proteins of the two groups of plants is minimal and essentially identical. The six dated ancient Sacred Lotus fruits range in age from 95 to 1,288 yr (with a mean age of 595 +/- 380 yr), evidently reflecting their production, deposition, and preservation at varying times during the intervening millennium.
Ex situ seed conservation aims to support species survival in the wild. This can be achieved by contributing genetic material for reintroduction. The goals of reintroduction are to increase both plant and population numbers, create self-sustaining populations and ultimately remove a species from its threatened listing. Quality seed collections with a broad genetic base are required to achieve this goal. Storage conditions that minimise deterioration of seeds will maximise the quality of seeds available for future use. Additionally, ex situ seed conservation provides long-term insurance against species or genotype loss until actual or potential threats can be removed. As threats to biodiversity escalate the most judicious conservation strategies will be ones that combine available resources to provide the highest possible degree of protection. Banked seeds are available irrespective of season and periods of low fecundity. Forward planning of reintroduction projects can be achieved with knowledge of the quantity and quality of banked seed. This paper discusses the challenges facing ex situ seed conservation while highlighting the benefits of integrating ex situ seed storage and plant reintroduction to help provide for better conservation outcomes.
THE International Board for Plant Genetic Resources (IBPGR) is encouraging the development of an international network of seed banks for the conservation of the genetic resources of the major crop species of the world and their wild relatives1. Most of the species in priority lists show ‘orthodox’ seed characteristics2, that is their longevity is prolonged in a defined manner by a reduction in moisture content (MC) (at least down to 5% MC, fresh weight basis) and temperature3. From a consideration of biological factors and the design and cost of seed storage facilities, IBPGR recommends that orthodox seeds are stored at −18 °C or less and at 5± 1% MC2. It is convenient to aim at −20 °C as the nominal temperature. Because of the accumulation of mutations associated with loss of viability4,5, IBPGR recommends regeneration of stocks (that is growing plants to provide new seeds from the old) when viability has fallen by 5% (ref. 2). To plan ancillary facilities and procedures, it is necessary to estimate regeneration intervals (time taken for viability to fall by 5%) for the major crop species. Such estimates pose three problems: there are genotypically controlled variations in longevity within a species; seed ‘quality’, determined by conditions before harvest and during processing, can affect subsequent longevity; and loss of viability at −20 °C is extremely slow, and so far it has been possible to predict regeneration interval only by questionable extrapolation from more favourable storage conditions5,6. We have examined these problems in barley (Hordeum distichum, L.) and have developed an approach which should make possible more accurate predictions from experiments lasting only 2 yr—even though fresh seed of most species shows no detectable loss of viability during this time.
The ability of orthodox seeds to survive long-term dry storage is a key prerequisite for ex situ seed conservation in genebanks. However, only a few credible observations of seed survival for ≥ 200 years have been reported. In this paper, seed survival is shown for three species under suboptimal storage conditions for a documented time of ≥ 203 years and carbon dated at 218–270 years. Two species that germinated are in the Fabaceae (Liparia sp. and Acacia sp.). A water-impermeable seed coat, and hence an inability to equilibrate with ambient relative humidity, may contribute to long-term survival of these species. The third species that germinated (Leucospermum sp.) does not have a water-impermeable seed coat, and long-term survival may be linked to an oxygen-impermeable barrier in the seed. These results for species from the Cape Floristic Region, South Africa, suggest adaptation for extreme longevity in seeds of species of seasonally dry, Mediterranean environments.
Seeds of different species are believed to have characteristic shelf lives, although data confirming this are scarce, and a mechanistic understanding of why this should be remains elusive. We have quantified storage performance of c. 42,000 seed accessions, representing 276 species, within the USDA National Plant Germplasm System (NPGS) collection, as well as a smaller experiment of 207 cultivars from 42 species. Accessions from the NPGS collection were harvested between 1934 and 1975, and had relatively high initial germination percentages that decreased at a variable rate during storage at both 5 and –18°C. Germination time courses, which represent the average performance of the species, were fitted to Avrami kinetics, to calculate the time at which germination characteristically declined to 50% (P50). These P50 values correlated with other longevity surveys reported in the literature for seeds stored under controlled conditions, but there was no correlation among these studies and seed persistence observed in the classic buried seed experiment by Duvel. Some plant families had characteristically short-lived (e.g. Apiaceae and Brassicaceae) or long-lived (e.g. Malvaceae and Chenopodiaceae) seeds. Also, seeds from species that originated from particular localities had characteristically short (e.g. Europe) or long (e.g. South Asia and Australia) shelf lives. However, there appeared to be no correlation between longevity and dry matter reserves, soluble carbohydrates and parameters relating to soil persistence or resource allocation. Although data from this survey support the hypothesis that some species tend to survive longer than others in a genebank environment, there is little information on the attributes of the seed that affect its storage performance.
The ever increasing demand for native plants and seed for use in restoration and revegetation has created a sizable industry. The large-scale production and planting of native plants have given rise to a suite of ecological concerns including collection impacts, genetic diversity, and provenance. This study examines the practices and beliefs of 12 restoration plant production companies in Colorado with regard to arising ecological issues and identifies where further research is needed. We found that native seed collection in Colorado was largely unregulated and unmonitored and impacts were unknown. Maintaining genetic diversity in restoration materials is costly and does not have universal support. The use of provenance material (or local ecotypes) was hotly contested with strong and sound arguments on both sides of the issue. Procurement of pure ecotypes was difficult because of the variety of institutions involved in production and complications such as artificial selection and cross-pollination.
Information on population genetics is fundamental to developing in situ or ex situ conservation strategies. Few researchers, however, have compared the genetic structure of restored and natural populations of threatened plant species. Metasequoia glyptostroboides Hu & Cheng (dawn redwood) (Taxodiaceae), a living fossil endemic to China, may be the most successfully recovered threatened species, with many more individuals and a much wider distribution than fossil records indicate. We used random amplification of polymorphic DNA markers to compare the genetic structure of artificial populations with that of wild ones and to determine whether the genetic structure of M. glyptostroboides has been recovered as has its distribution. The genetic variation of wild populations of M. glyptostroboides was lower than the average of gymnosperms, indicating the effects of glaciations and recent habitat loss and fragmentation. Genetic variation in artificial populations was less, but not substantially, compared with wild populations. The unweighted pair group method with arithmetic mean revealed that the wild and the artificial populations formed two distinct groups. Artificial populations were more similar to each other (mean Nei's genetic distance = 0.0924) than to wild populations (mean distance = 0.2054). This might be the result of biased seed collection, vegetative propagation, or a mixture of propagules from different populations and an ultimate propagule source. These results suggest that although the quantity and distribution range have been successfully restored, the genetic structure of M. glyptostroboides has not recovered appropriately, given the loss of genetic variation and biased genetic composition in artificial populations. Therefore, in addition to protecting the wild populations, additional ex situ genetic reserves should be established based on genetic knowledge and via appropriate approaches. We suggest that population genetic and demographic indices should be considered when downlisting or delisting threatened species.
Resumen: Es fundamental contar con información sobre genética poblacional para el desarrollo de estrategias de conservación in situ o ex situ. Sin embargo, pocos investigadores han comparado la estructura genética de poblaciones restauradas y naturales de especies de plantas amenazadas. Metasequoia glyptostroboides Hu & Cheng (Taxodiaceae), un fósil viviente endémico de China, puede ser la especie amenazada recuperada más exitosamente, con mucho más individuos y una distribución mucho mayor que la indicada por registros fósiles. Utilizamos amplificaciones aleatorias de marcadores de ADN polimórfico para comparar la estructura genética de poblaciones artificiales con la de poblaciones silvestres y para determinar si la estructura genética de M. glyptostroboides se ha recuperado como lo ha hecho su distribución. La variación genética de poblaciones silvestres de M. glyptostroboides fue menor que la del promedio de gimnospermas, lo que indica efectos de glaciaciones y pérdida y fragmentación reciente de hábitat. La variación genética en poblaciones artificiales fue menor, pero no sustancialmente, comparada con poblaciones silvestres. El método de grupos pareados con media aritmética reveló que las poblaciones artificiales y silvestres formaron dos grupos distintos. Las poblaciones artificiales fueron más similares entre si (distancia genética de Nei promedio = 0.0924) que con poblaciones silvestres (distancia promedio = 0.2054). Esto puede ser el resultado de la colecta sesgada de semillas, propagación vegetativa o mezcla de propágulos de diferentes poblaciones y una fuente terminal de propágulos. Estos resultados sugieren que aunque la cantidad y la distribución se han restaurado exitosamente, la estructura genética de M. glyptostroboides no se ha recuperado adecuadamente, dada la pérdida de variación genética y la composición genética sesgada de poblaciones artificiales. Por lo tanto, además de proteger a las poblaciones silvestres, se deben establecer reservas genéticas ex situ adicionales con base en conocimiento genético y por medio de métodos adecuados. Sugerimos que se deben considerar índices demográficos y de genética poblacional cuando se revise el estatus de especies amenazadas.
Summary • An analysis was made of seed traits along a north–south gradient spanning 19° of latitude in Europe using Aesculus hippocastanum, which originates from Greece and the Balkans and has been introduced throughout Europe. • Because summer temperatures decrease with increasing latitude in Europe, we tested the hypothesis that the heat sum during seed development influences physical, physiological and biochemical seed traits. • Seeds from Greece (within the natural range) had a fresh mass five times higher than those from Scotland (most northerly seed lot), and a lower axis moisture content and solute potential. In addition, Greek seeds germinated at cooler temperatures, and were more desiccation tolerant. Principal component analysis (PCA) showed that the observed patterns in seed characteristics were consistent and predictable: a single PCA axis explained 86.6% of the variation in the dataset. This axis correlated strongly with the heat sum accumulated by the seeds during development. • The results support the notion that seeds from further north were shed less developed as a consequence of cooler temperatures during development, and provide a quantitative explanation for intraspecies variability in recalcitrant seed traits for this and, possibly, other species.
The lack of realistic estimates of the costs of protected area establishment and effective management can hinder conservation planning and result in under-funded “paper parks” that fail to meet conservation goals. This study comprises the first comprehensive and systematic estimate of the costs of conserving a globally recognised biodiversity hotspot, the Cape Floristic Region. To our knowledge, it is also the first study to use specific relationships between protected area attributes and management costs to estimate the long-term costs of implementing a regional conservation plan. We derived a configuration for an expanded protected area system and two off-reserve mechanisms (contractual reserves and other incentive mechanisms) that achieve explicit conservation targets for biodiversity pattern and process identified in a systematic conservation planning process. Using a costing model, we then estimated the costs of establishing and maintaining this reserve system. Although the reserve system is one of many potential configurations that may achieve the designated conservation targets, the results indicate that the costs of conservation are substantial. An expenditure of $45.6 million per year, assuming a 20-year implementation horizon, is required to develop a representative reserve system, while the annual costs of maintaining this system are $24.4 million. Owing to the economies of scale, especially the marked increase in unit management costs when protected area size <600 ha, the predicted cost of managing the expanded system was only 1.2 times that of the existing system. Overall, the level of expenditure required to effectively conserve the region's biodiversity is low relative to its regional and global significance.
The ability of seeds to survive desiccation is an important functional trait and is an integral part of plant regeneration ecology. Despite this, the topic has received relatively little attention from ecologists. In this study, we examine the relationships between seed desiccation tolerance and two important aspects of plant regeneration ecology: habitat and dormancy. This is done by comparative analysis of a data set of 886 tree and shrub species from 93 families.
The proportion of species displaying desiccation sensitive seeds declines as the habitat becomes drier, and possibly also cooler, although the latter observation requires cautious interpretation. Desiccation sensitivity is most common in moist, relatively aseasonal vegetation zones, but is infrequent in, though not absent from arid and highly seasonal habitats.
The highest frequency of desiccation sensitivity occurs in non‐pioneer evergreen rain forest trees, although 48% of the species examined have desiccation tolerant seeds. In contrast, all pioneer taxa within the data set have drying tolerant seeds.
Desiccation sensitivity is more frequent in seeds that are non‐dormant on shedding ( c. 31%), than dormant ( c. 9%). Highest frequencies of drying tolerance occur in seeds with physical or combinational dormancy, at 99% and 100%, respectively.
Although there is an association between non‐dormancy and desiccation sensitivity in both tropical and temperate zones, the relationship does not appear to be causal.
Working from the hypothesis that seed desiccation sensitivity represents a derived state in extant species, we use the results to investigate and discuss possible ecological trade‐offs and associated fitness advantages. These may explain the hypothesized repeated loss of this trait. The frequent association between large seed size and desiccation sensitivity is also considered.
Seeds of four cultivars of arabica coffee (Coffea arabica L.) were tested for germination following hermetic storage for up to 12 months at several different combinations of temperatures
between −20 °C and 15 °C and moisture contents between 5% and 10% (wet basis). Most of the seeds from one cultivar withstood
desiccation to between 5% and 6% moisture content, a seed water potential of approximately −250 MPa, but those of the remaining
three cultivars were much more sensitive to desiccation damage. Moreover, in all four cultivars, seed longevity at cool and
sub-zero temperatures, and at low moisture contents did not conform with orthodox seed storage behaviour: viability was lost
more rapidly under these conditions than at either warmer temperatures or higher moisture contents. The results confirm that
coffee seeds fail to satisfy the definitions of either typical orthodox or recalcitrant seed storage behaviour. These results,
therefore, point to the possibility of a third category of storage behaviour intermediate between those of orthodox and recalcitrant
seeds. One of the main features of this category is that dry seeds are injured by low temperatures.
Seed banking has been the single most significant reaction of the research community to the alarming rates of plant genetic
erosion occurring in the wild. One enduring challenge for a wiser utilization of the resources enclosed in seed banks, however,
has been the estimation of their genetic potentials for agriculture's benefit. Key to detecting in landraces and/or wild relatives
of modern crops any allelic variant lost during domestication and crop improvement is the use of molecular information to
determine structure, evolution, and function of the genes harbouring these alleles. This paper reviews some of the theoretical
and statistical issues surrounding the use of molecular population genetics tools for the detection of agronomical valuable
alleles in seed banks. Emphasis is made on the technical limitations imposed by seed banking that may lessen the success of
integrated and multi-disciplinary molecular approaches. The influence that population stratification and linkage disequilibrium
exert on specific experimental designs for a better understanding of the evolutionary history of potential agronomic-related
genes is also examined.