Seed Bank Research Articles

Effects of Prescribed Fire and Thinning on the Spatial Heterogeneity of the Seed Bank in a Mixed Oak Forest

Abstract Prescribed fire and thinning are commonly employed management practices in mixed-oak forests of the central Appalachians. The effects of these practices on the soil seed bank are important to consider in order to evaluate the full impact of these treatments on plant community dynamics in the understory. Species composition of the soil seed bank was examined under three treatments: thin, burn, and thin followed by burning, and an untreated control. Thinning was conducted in Fall 2000, and burns were conducted in Spring 2001. Soil samples were collected in March 2004, three years following treatment. Species composition was assessed by seedling emergence. Seventy total species were found in the seed bank. Ruderal species such as Erechtites hieraciifolia, Carex spp., and Rubus spp. were the most commonly occurring species across all treatments. No significant difference in species composition or proportion of functional groups was found between any of the treatment groups. However, as found in previ...

Seeds: time capsules of life

Pollen was recognised as a benchmark for art and science collaboration amongst botanists at Kew and laid the ground for further publications. Seeds, produced together with Dr. Wolfgang Stuppy a seed morphologist from the Millennium Seed Bank, Wakehurst Place, is a response to this opportunity for artistic research to make a unique contribution to the understanding and appreciation of an organism vital to the preservation of bio-diversity. Alongside a scientific text by Stuppy, tracing the evolution of seeds and the many morphological characteristics they have evolved to ensure efficient dispersal I developed an extensive collection of macro and micro coloured photographic images to reveal the seeds as powerful phytomorphic motifs. Focussing particularly on small seeds (below 4mm) the use of a new digital scanning electron micrography enabled the production of extremely high-resolution images, which reveal complex and diverse surface structures. Extending the canon of botanical representation I examine the contrasting representational modes for depicting plants that distinguish the individual approach of artists, scientists and illustrators and challenge the orthodoxies of conventional representation. Employing artistic modes of visualisation in this pioneering way I was able to reveal forms and functions of the seed structures which pushes forward the impact that the work has on both scientific and art and design communities. In a further essay on the way in which plant structures have long provided an example and template for architectural form, from Vitruvius to Nicholas Grimshaw’s Eden Project, I extend this principal further through the comparison of contemporary architectural form with seed structures. In 2006 I was elected as a fellow of the Linnaean Society for my contribution in the field and in 2007 the book was awarded a gold medal at the Independent Publishers Awards in New York, for the most innovative concept of the year.

A review of similarity between seed bank and standing vegetation across ecosystems

A review of similarity between seed bank and standing vegetation across ecosystems

Post-dispersal embryo growth and acquisition of desiccation tolerance inAnemone nemorosaL. seeds

AbstractA UK seed conservation collection ofAnemone nemorosaL. seeds held at the Millennium Seed Bank (MSB) showed low viability in its first post-storage test. Because achenes ofA. nemorosaare naturally dispersed when they are green, we tested the hypothesis that seeds may not be fully desiccation tolerant and storable at the time of natural dispersal, and that a post-harvest treatment could increase the proportion of desiccation-tolerant seeds. Achenes harvested at the point of natural dispersal in late May in 2003 and 2004 were either placed immediately on 1% water agar at 20°C (‘laboratory’ treatment), or placed in nylon sachets and buried in leaf litter among plants growing in the wild (‘field’ treatment). Samples were withdrawn at intervals over a period of 168 d and tested for desiccation tolerance (drying to 0.059 g H2O (g DW)− 1) and longevity (controlled ageing at 60% relative humidity and 45°C). An initial increase, followed by a decline, in the proportion of seeds surviving desiccation and in the longevity of both laboratory- and field-treated samples coincided with the development of embryos from globular to heart- and then torpedo-shaped. Developmental arrest was not required for the acquisition of desiccation tolerance, and continued growth and development of the embryo resulted in a loss of desiccation tolerance, similar to that seen in orthodox seeds upon radicle emergence. Furthermore, whileA. nemorosaseeds, like many from theRanunculaceaefamily, might be described as having morphological or morphophysiological dormancy, this lack of developmental arrest does not fit with the usual concept of dormancy. The implications of these results for the classification systems of seed-storage behaviour and dormancy, and for the long-term conservation of seeds ofA. nemorosa, are discussed.

Saving Seeds, Saving Culture: A Case Study of a Heritage Seed Bank

This article examines a heritage seed saving organization, the Seed Savers Exchange (SSE), a nonprofit seed bank in northeastern Iowa. To begin, I focus on how SSE conceives of seeds and nature more broadly. From here, the analysis moves to understand how these “ideas” of nature shape the materiality that is ultimately conserved. Next, the value statements of conservation are analyzed. All conservation policies and practices rest upon normative assumptions about what type of nature ought to be conserved. The final section sets out to detail what some of those value statements are as they relate to SSE, and how they are used to instill within people similar commitments to conservation overall and seed saving in particular. When taken together, these three components—(1) conceptions of nature, (2) the materiality being conserved, and (3) the values embedded in all conservation practices—signify what I call the “trialectic of conservation.”

Conservation of African Leafy Vegetables in South Africa

The nutritional and cultural importance of African Leafy Vegetables has become very important in South Africa in the past few years. Recent research has also confirmed these issues, leading to the incorporation of African Vegetables into the core business of the ARC. ARC -Roodepl aat wants to improve the distribution and conservation status of African Leafy Vegetables. Geographical collection data on Amarant, Cleome gynandra, Corchorus olitorius and Vigna inguiculata was obtained from the National Botanical Institute and the data w as analyzed with DIVA and Flora map. Ecogeographical distribution maps were drawn to predict the possible distribution of the species. Germplasm of African Leafy Vegetables was collected during routine visits and the conservation status was discussed with participants in the study areas of Arthurstone in Bushbuckridge, Watershed near Ladysmith and Mars/Glenroy near Polokwane. Germplasm of various species were also collected in collaboration with the Plant Genetic Resource Centre (NPGRC) of the Department of Agriculture in Arthurstone and Watershed. The NPGRC included leafy vegetables in their mandate since this trip. Seed flow diagrams were used to discuss the Watershed com munity’s seed exchange systems. It was clear when discussing African leafy vegetable s in communities that their conservation and utilization are declining. Also looking at the trendlines of African Vegetables availability and utilization it is clear that the use and availability of African Leafy vegetables are declining due to various rea sons. Two major reasons are the negative image of the African Leafy Vegetables and the increased use of “exotic” vegetables like spinach and carrots. The active promotion, use and conservation of African Leafy Vegetables are important if we want to increase the production potential and potential contribution towards food security in South Africa. This will ensure that the status of these crops is enhanced, specifically their contributing towards sustainable nutrition as well as sustainable production. Resul ts from promotion activities in the project (reported in another paper) indicated that the negative image of African Leafy Vegetables could be reversed and also had an affect on the roll -out of the project to other areas of research such as plant protection, nutritional analysis and food safety, crop science and indigenous knowledge systems.

Fungal effects on seed bank persistence and potential applications in weed biocontrol: A review

Summary Seed bank formation plays an important role in plant population dynamics. However, buried seeds face several mortality factors, including the decay caused by microbial activity. Recent seed burial studies involving both fungicide-treated seeds and untreated seeds provide evidence for the importance of saprophytic soil fungi as a seed mortality factor. In this review, we summarize the available evidence. We discuss the influence of abiotic and biotic environmental factors, the specificity of plant-fungal associations at the seed level and mechanisms of resistance to seed decay. Finally, we discuss implications for plant communities and for the biocontrol of agricultural weeds.

Relationship between the soil seed bank and vegetation of tall grassland of Spartina argentinensis.

Tall grass communities of Spartina argentinensis Parodi are the most widespread plant communities in a large saline depression in Santa Fe, Argentina. The vegetation and soil seed bank of these communities have been studied. However, there is no information about the relationship between them. We worked with previous data obtained from the Federico Wildermuth Reserve, Colonia Bel Grano, Departamento San Martin, Santa Fe, Argentina (31°57’ S; 61°23’ W) and used the cover-abundance of the plant species and density of the soil seed bank for 1998 and 1999. The relationship between plant types C3 and C4 (C3/C4) and annual/perennial functional groups were determined. At the same time, the similarity index and the relationship between coverabundance and density of the shared species was determined. According to results obtained, plant species of type C3 were more frequent in the soil seed bank, while plant species of type C4 were more abundant in the vegetation. There was no signifi cant correlation between coverabundance in the vegetation and soil seed bank density of the common species. The similarity index was very low due to the fact that the number of species common to vegetation and seed bank was very low. In conclusion, there was a low relationship between species of the soil seed bank and vegetation with plant species type C3 and C4 as predominant species, respectively. Los pajonales de Spartina argentinensis Parodi ocupan grandes extensiones en bajos salinos de la provincia de Santa Fe, Argentina. La vegetacion y el banco de semillas del suelo de estas comunidades han sido analizados pero se desconoce la relacion entre ambos compartimentos de la comunidad. Se trabajo con datos obtenidos previamente de la Reserva Federico Wildermuth Colonia Bel Grano, Departamento San Martin, Santa Fe, Argentina (31°57’ S; 61°23’ W). Con este proposito se empleo informacion sobre abundancia-cobertura de la comunidad aerea y densidad del banco, discriminada por especies, obtenidos durante 1998 y 1999. Se calcularon: proporciones de grupos funcionales de especies vegetales C3 y C4 y anuales/perennes, se determino el indice de similitud y la relacion entre abundancia-cobertura y densidad del banco de semillas, para las especies comunes. Las especies tipo C3 predominaron en el banco y las tipo C4 en la vegetacion. Las especies comunes a ambos compartimentos no presentaron correlacion entre la abundancia-cobertura del suelo y la densidad en el banco. El numero de especies comunes fue muy bajo, por lo cual los indices de similitud fueron tambien bajos. En conclusion, los resultados obtenidos en este estudio demostraron la existencia de una escasa relacion entre el banco de semillas del suelo y la vegetacion en pie, en los cuales predominan plantas C3 y C4, respectivamente.

Seed Morphology, Germination Phenology, and Capacity to Form a Seed Bank in Six Herbaceous Layer Apiaceae Species of the Eastern Deciduous Forest

We compared seed mass, seed morphology, and long-term germination phenology of three monocarpic (M) and three polycarpic (P) Apiaceae species of the herbaceous layer of the Eastern Deciduous Forest. Seeds (mericarps) of the six species differed considerably in mass, shape, and ornamentation. Mean seed masses were ranked Cryptotaenia canadensis (M) , Thaspium barbinode (P) , Sanicula canadensis (M) , S. gregaria (P) , Osmorhiza claytonii (P) , S. trifoliata (M). Germination peaks occurred in the first or second spring following sowing. Germination of a few seeds was delayed until the sixth year. Regardless of seed mass or morphology, each species has the potential to form a (modified) Type III or (modified) Type IV persistent soil seed bank. Occurrence of a germination peak in the first or in the second year following seed maturity was related to time of dispersal in autumn and to type of seed dormancy.

Seed size, shape and persistence in the soil in an Iranian flora

Previous studies on several floras have shown that species with small, rounded seeds tend to accumulate persistent seed banks in the soil, while species with larger, less compact seeds do not. The suggested underlying mechanism is predation. Small seeds experience less predation and are more likely to become buried, which itself offers significant protection from predation by vertebrates. The relationship between seed size and shape and persistence in the soil was examined for the flora of the Arasbaran Protected Area in northwest Iran. Seed size was related to persistence in the soil in Iran in the same way as in most other floras examined, but seed shape was not. It is suggested that predation prevents persistence of large seeds in most floras. Where large-seeded persistent species predominate, for example in Australia and (to a lesser extent) in New Zealand, other factors may interfere with the relationship between seed size and predation.

Norway unveils design of 'doomsday' seed bank

Norway unveils design of 'doomsday' seed bank

Telomeres and seed banks

We have found that a progressive loss of telomeric sequences occurs from high molecular weight DNA with an increasing appearance at low molecular weight as the periods of storage in the dry state were extended in time to provide seed germination loss from 98 to 0%. Telomere distribution would appear to follow the general pattern of DNA random fragmentation that occurs in the embryos of seeds stored in the dry state, but there are also indications of an overall telomere loss from DNA as a consequence of storage. There is a need for a convenient "equality marker" for the seeds that can be monitored over time. Reviewing the implications of our results very carefully we believe that there is considerable potential in the use of telomere sequences to mark embryo ageing of seeds held in Seed Banks.

Distinguishing between persistence and dormancy in soil seed banks of three shrub species from fire-prone southeastern Australia

Question: Is primary dormancy required for seed bank persistence of Leucopogon species? How does the distinction between dormancy and persistence affect our understanding of seed bank dynamics in fire-prone regions? Location: Sclerophyllous plant communities, Sydney region, southeastern Australia. Methods: Seed bank longevity of three morphophysiologically dormant species was ascertained using seed burial trials. Seeds of each species were buried in situ in replicate mesh bags and retrieved annually over three years. Laboratory germination trials and embryo growth measurements over time were used to establish in which order each component of dormancy was overcome, and whether seed banks persisted after the loss of primary dormancy. Results: All species had long-term persistent seed banks, with estimated half-lives between 3.5 and 5.5 years. Physiological dormancy was broken by stratification prior to embryo growth, during the first year of burial. Seeds were able to germinate after retrieval, in light and...

Herbicide Impacts on Soil Seed Bank in a Sugarbeet Rotation

Herbicide Impacts on Soil Seed Bank in a Sugarbeet Rotation

Handbook of seed science and technology

Handbook of seed science and technology

Stochastic stable population growth in integral projection models: theory and application

Stochastic matrix projection models are widely used to model age- or stage-structured populations with vital rates that fluctuate randomly over time. Practical applications of these models rest on qualitative properties such as the existence of a long term population growth rate, asymptotic log-normality of total population size, and weak ergodicity of population structure. We show here that these properties are shared by a general stochastic integral projection model, by using results in (Eveson in D. Phil. Thesis, University of Sussex, 1991, Eveson in Proc. Lond. Math. Soc. 70, 411-440, 1993) to extend the approach in (Lange and Holmes in J. Appl. Prob. 18, 325-344, 1981). Integral projection models allow individuals to be cross-classified by multiple attributes, either discrete or continuous, and allow the classification to change during the life cycle. These features are present in plant populations with size and age as important predictors of individual fate, populations with a persistent bank of dormant seeds or eggs, and animal species with complex life cycles. We also present a case-study based on a 6-year field study of the Illyrian thistle, Onopordum illyricum, to demonstrate how easily a stochastic integral model can be parameterized from field data and then applied using familiar matrix software and methods. Thistle demography is affected by multiple traits (size, age and a latent "quality" variable), which would be difficult to accommodate in a classical matrix model. We use the model to explore the evolution of size- and age-dependent flowering using an evolutionarily stable strategy (ESS) approach. We find close agreement between the observed flowering behavior and the predicted ESS from the stochastic model, whereas the ESS predicted from a deterministic version of the model is very different from observed flowering behavior. These results strongly suggest that the flowering strategy in O. illyricum is an adaptation to random between-year variation in vital rates.

Development of novel methods for the initiation of in vitro bryophyte cultures for conservation

The value of ex situ plant collections for conservation is increasingly recognised. The Royal Botanic Gardens, Kew (RGB, Kew) has been pioneering methods for the development of such collections with the establishment of the Millennium Seed Bank and a project for the ex situ conservation of threatened UK bryophytes (mosses, liverworts, hornworts). A broad range of bryophytes are currently held in a tissue culture collection at RBG, Kew on sucrose-free ¼ or ½ Murashige & Skoog or Knops minimal medium. The efficacy of the novel sterilising agent Sodium dichloroisocyanurate (NaDCC) was tested on a range of taxa, utilising a variety of bryophytic initiation material. Concentrations of 1% (w/v) for 3 min and 0.5% (w/v) for 2 min, without the addition of detergent, were found to be successful in initiating cultures from sporophytes and leafy gametophores respectively. Initiation of cultures from wild-collected sporophytes was more successful than from wild-collected gametophores. However, pre-culturing of gametophore material was found to enhance success rate of procedures. Transferring visibly clean material away from contamination post-initiation was also determined to increase protocol success rate. The ability of the biocide Plant Preservative MixtureTM (PPMTM) to control fungal and bacterial contamination in bryophyte protonemal cultures was also tested, but not found to be suitable. However, results obtained indicated that contamination may confer resistance on the moss against the phytotoxic effects of the biocide. Methods developed have wider applicability for the establishment of in vitro collections of other threatened plants.

Agro-morpho-logical and sensory characterization of cocoyam (<i>Xanthosoma sagittifolium</i> (L) (Schott) germplasm in Ghana

Seventy-eight accessions of cocoyam (Xanthosoma sagittifolium (L.) Schott) were collected from seven regions of Ghana to gather the available germplasm for conservation and use. The materials were planted at the Plant Genetic Resources Centre (PGRC), Bunso and characterized agro-morphologically using the International Plant Genetic Resources Institute's (IPGRI) descriptors for Xanthosoma. Twenty-one qualitative and 10 quantitative characters were studied. Two main groups were identified based on characters of the pseudo-stem and colouration of the apical portions of cormels. However, three groups were identified based on cooked cormel qualities. The qualitative character which recorded the highest polymorphism was the cooking quality of cormels with a diversity index of 0.540. A cluster analysis using the 31 characters showed eight distinct groupings. A further characterization using molecular methods is recommended to indicate more variability or otherwise in the germplasm. Ghana Journal of Agricultural Science Vol. 37 2004: 23-31

Wet-season Dormancy Release in Seed Banks of a Tropical Leguminous Shrub is Determined by Wet Heat

Hard-seeded (physical) dormancy is common among plants, yet mechanisms for dormancy release are poorly understood, especially in the tropics. The following questions are asked: (a) whether dormancy release in seed banks of the tropical shrub Parkinsonia aculeata (Caesalpiniaceae) is determined by wet heat (incubation under wet, warm to hot, conditions); and (b) whether its effect is modified by microclimate. A seed burial trial was conducted in the wet-dry tropics (northern Australia) to compare dormancy release across different habitats (open, artificial cover, ground cover and canopy cover), burial depths (0, 3 and 20 cm) and burial durations (2, 6 and 14 weeks). Results were compared with predictions using a laboratory-derived relationship between wet heat and dormancy release, and microclimate data collected during the trial. Wet heat (defined as the soil temperature above which seeds were exposed to field capacity or higher for a cumulative total of 24 h) was 43.6 degrees C in the 0 cm open treatment, and decreased with increasing shade and depth to 29.5 degrees C at 20 cm under canopy cover. The dormancy release model showed that wet heat was a good predictor of the proportion of seeds remaining dormant. Furthermore, dormancy release was particularly sensitive to wet heat across the temperature range encountered across treatments. This resulted in a 16-fold difference in dormancy levels between open (<5 % of seeds still dormant) and covered (82 %) microhabitats. These results demonstrate that wet heat is the principal dormancy release mechanism for P. aculeata when conditions are hot and wet. They also highlight the potential importance of microclimate in driving the population dynamics of such species.

News from Australian Partners - Millennium Seed Bank Coordinator

News from Australian Partners - Millennium Seed Bank Coordinator