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Sample records for macrophyte seed bank

  1. Diaspore bank of aquatic macrophytes maintaining species diversity in a Neotropical pond

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    Fernando Alves Ferreira

    2016-12-01

    Full Text Available The diaspore bank is an important component of biological diversity acting mainly as storage and source of diaspores, which also indicate dynamics and patterns of maintenance of plant diversity. We tested the hypothesis that the diaspore bank would be the responsible factor for the maintenance of the aquatic plant species, used two techniques to evaluate the diaspore bank: seedling emergence and direct counting of field samples. Density and richness of the diaspore bank were correlated with plant cover of the aquatic macrophyte communities and also with the euphotic zone radiation in different phases of the hydrological cycle. The diaspore bank is a key factor in maintenance of aquatic macrophyte assemblages in this pond. Nymphaea amazonum was one of the dominant species in the pond and presented temporally peaks of plant cover. Furthermore, depth allowed induction of germination of stored diaspores. Therefore, the diaspore bank may predict which species colonizes a site when environmental characteristics are favorable and allows inferring which processes are linked to changes in structure of aquatic macrophyte assemblages. These mechanisms are the means for recovery of macrophyte species under natural disturbances, represented by water level oscillations in floodplains.

  2. Microscale Insight into Microbial Seed Banks

    Science.gov (United States)

    Locey, Kenneth J.; Fisk, Melany C.; Lennon, J. T.

    2017-01-01

    Microbial dormancy leads to the emergence of seed banks in environmental, engineered, and host-associated ecosystems. These seed banks act as reservoirs of diversity that allow microbes to persist under adverse conditions, including extreme limitation of resources. While microbial seed banks may be influenced by macroscale factors, such as the supply of resources, the importance of microscale encounters between organisms and resource particles is often overlooked. We hypothesized that dimensions of spatial, trophic, and resource complexity determine rates of encounter, which in turn, drive the abundance, productivity, and size of seed banks. We tested this using >10,000 stochastic individual based models (IBMs) that simulated energetic, physiological, and ecological processes across combinations of resource, spatial, and trophic complexity. These IBMs allowed realistic dynamics and the emergence of seed banks from ecological selection on random variation in species traits. Macroscale factors like the supply and concentration of resources had little effect on resource encounter rates. In contrast, encounter rates were strongly influenced by interactions between dispersal mode and spatial structure, and also by the recalcitrance of resources. In turn, encounter rates drove abundance, productivity, and seed bank dynamics. Time series revealed that energetically costly traits can lead to large seed banks and that recalcitrant resources can lead to greater stability through the formation of seed banks and the slow consumption of resources. Our findings suggest that microbial seed banks emerge from microscale dimensions of ecological complexity and their influence on resource limitation and energetic costs. PMID:28119666

  3. Methodological bias in the seed bank flora holds significant implications for understanding seed bank community functions.

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    Plue, J; Colas, F; Auffret, A G; Cousins, S A O

    2017-03-01

    Persistent seed banks are a key plant regeneration strategy, buffering environmental variation to allow population and species persistence. Understanding seed bank functioning within herb layer dynamics is therefore important. However, rather than assessing emergence from the seed bank in herb layer gaps, most studies evaluate the seed bank functioning via a greenhouse census. We hypothesise that greenhouse data may not reflect seed bank-driven emergence in disturbance gaps due to methodological differences. Failure in detecting (specialist) species may then introduce methodological bias into the ecological interpretation of seed bank functions using greenhouse data. The persistent seed bank was surveyed in 40 semi-natural grassland plots across a fragmented landscape, quantifying seedling emergence in both the greenhouse and in disturbance gaps. Given the suspected interpretational bias, we tested whether each census uncovers similar seed bank responses to fragmentation. Seed bank characteristics were similar between censuses. Census type affected seed bank composition, with >25% of species retrieved better by either census type, dependent on functional traits including seed longevity, production and size. Habitat specialists emerged more in disturbance gaps than in the greenhouse, while the opposite was true for ruderal species. Both censuses uncovered fragmentation-induced seed bank patterns. Low surface area sampling, larger depth of sampling and germination conditions cause underrepresentation of the habitat-specialised part of the persistent seed bank flora during greenhouse censuses. Methodological bias introduced in the recorded seed bank data may consequently have significant implications for the ecological interpretation of seed bank community functions based on greenhouse data. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  4. Maximizing the phylogenetic diversity of seed banks.

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    Griffiths, Kate E; Balding, Sharon T; Dickie, John B; Lewis, Gwilym P; Pearce, Tim R; Grenyer, Richard

    2015-04-01

    Ex situ conservation efforts such as those of zoos, botanical gardens, and seed banks will form a vital complement to in situ conservation actions over the coming decades. It is therefore necessary to pay the same attention to the biological diversity represented in ex situ conservation facilities as is often paid to protected-area networks. Building the phylogenetic diversity of ex situ collections will strengthen our capacity to respond to biodiversity loss. Since 2000, the Millennium Seed Bank Partnership has banked seed from 14% of the world's plant species. We assessed the taxonomic, geographic, and phylogenetic diversity of the Millennium Seed Bank collection of legumes (Leguminosae). We compared the collection with all known legume genera, their known geographic range (at country and regional levels), and a genus-level phylogeny of the legume family constructed for this study. Over half the phylogenetic diversity of legumes at the genus level was represented in the Millennium Seed Bank. However, pragmatic prioritization of species of economic importance and endangerment has led to the banking of a less-than-optimal phylogenetic diversity and prioritization of range-restricted species risks an underdispersed collection. The current state of the phylogenetic diversity of legumes in the Millennium Seed Bank could be substantially improved through the strategic banking of relatively few additional taxa. Our method draws on tools that are widely applied to in situ conservation planning, and it can be used to evaluate and improve the phylogenetic diversity of ex situ collections. © 2014 Society for Conservation Biology.

  5. SEED BANKS FOR MAGNETIC FLUX COMPRESSION GENERATORS

    Energy Technology Data Exchange (ETDEWEB)

    Fulkerson, E S

    2008-05-14

    In recent years the Lawrence Livermore National Laboratory (LLNL) has been conducting experiments that require pulsed high currents to be delivered into inductive loads. The loads fall into two categories (1) pulsed high field magnets and (2) the input stage of Magnetic Flux Compression Generators (MFCG). Three capacitor banks of increasing energy storage and controls sophistication have been designed and constructed to drive these loads. One bank was developed for the magnet driving application (20kV {approx} 30kJ maximum stored energy.) Two banks where constructed as MFCG seed banks (12kV {approx} 43kJ and 26kV {approx} 450kJ). This paper will describe the design of each bank including switching, controls, circuit protection and safety.

  6. Soil seed bank dynamics in hayfield succession

    NARCIS (Netherlands)

    Bekker, RM; Bakker, JP; Fresco, LFM; Verweij, G.L.

    2000-01-01

    1 Changes in the species composition of the soil seed bank were determined in a dry and a more species-rich wet chronosequence. Each sequence represented a 25-year hayfield succession following cessation of fertilizer application in the Drentse A Nature Reserve (NL). where the vegetation has been st

  7. The impact of groundwater level on soil seed bank survival

    NARCIS (Netherlands)

    Bekker, RM; Oomes, MJM; Bakker, JP

    Seed longevity of plant species is an important topic in restoration management, and little is known about the effects of environmental conditions on seed survival and longevity under natural conditions. Therefore, the effect of groundwater level on the survival of seeds in the soil seed bank of a

  8. Using Soil Seed Banks for Ecological Education in Primary School

    Science.gov (United States)

    Ju, Eun Jeong; Kim, Jae Geun

    2011-01-01

    In this study, we developed an educational programme using soil seed banks to promote ecological literacy among primary school-aged children. The programme consisted of seven student activities, including sampling and setting soil seed banks around the school, watering, identifying seedlings, and making observations about the plants and their…

  9. Using Soil Seed Banks for Ecological Education in Primary School

    Science.gov (United States)

    Ju, Eun Jeong; Kim, Jae Geun

    2011-01-01

    In this study, we developed an educational programme using soil seed banks to promote ecological literacy among primary school-aged children. The programme consisted of seven student activities, including sampling and setting soil seed banks around the school, watering, identifying seedlings, and making observations about the plants and their…

  10. 沉水植物菹草的人工种子技术%STUDY OF ARTIFICIAL SEEDS OF SUBMERGED MACROPHYTE POTAMOGETON CRISPUS L.

    Institute of Scientific and Technical Information of China (English)

    安彦杰; 张彦辉; 杨劭

    2009-01-01

    Restoration of submerged vegetation is the key step of restoration of aquatic ecosystem in eutrophic lakes. The seed bank was strongly destroyed in many eutrophic lakes of China, it is necessary to get plenty of seedlings for restoration of submerged vegetation because of the difficulty of getting enough macrophyte seeds. Usually, seedlings of submerged macrophytes have to be obtained from other water bodies. Transplantation may destroy the source vegetation and encounter shortage of seedlings in case of lack of vegetation in nearby water bodies. The technique of artificial seeds is a promising method to provide a large number of seedlings in a short time without limitation of season, long distant transportation and harm to the natural macrophyte community.In order to establish the method for the preparation of artificial seeds of submerged macrophytes, a common submerged macrophte Potamogeton crispus L. was selected as experimental material. In this study, the artificial seed of P. crispus was obtained by using node segments as explant, buds were induced in induction medium. The node segments with buds of P. crispus were encapsulated with sodium alginate and calcium chloride to form artificial seeds. The effects of hormone types and concentration in capsule, temperature, light intensity, concentration of nitrogen and phosphorus, sediment types on the germination and conversion of artificial seeds of P. crispus were investigated. An experiment of germination and conversion of the artificial seeds in lake was also conducted. The hormones supplemented in the capsules could promote the germination of artificial seeds. The result showed that the germination and conversion rates of artificial seeds, which embedded in IBA 1.0 mg/L and 6-BA 0. 5 mg/L, were 80% and 20% respectively in autoclaved tap water. No significant effect of temperature was found on the germination and conversion in range of 15-25℃. Similarly nitrogen and phosphorus caused no significant change on

  11. Diversity in soil seed bank of Sinai and implications for conservation ...

    African Journals Online (AJOL)

    Administrator

    Key words: Sinai, soil seed bank, arid environments, diversity indices, conservation, restoration. INTRODUCTION .... germination for the last season was completed and seed dispersal ...... heterogeneity which is common for desert seed banks.

  12. Monkey and dung beetle activities influence soil seed bank structure

    OpenAIRE

    Feer, François; Ponge, Jean-François; Jouard, Sylvie; Gomez, Doris

    2013-01-01

    International audience; In Neotropical forests, dung beetles act as efficient secondary dispersers of seeds that are dispersed primarily by red howler monkeys. Here, we investigated the origins of soil seed bank variability in relation to monkey and dung beetle activity, to assess the impact of dung beetles on seed fate, and their adaptability to resource availability. This question is important to better understand the process of tree regeneration, and is especially timely in the current con...

  13. Study of Soil Seed Banks in Antaibao Opencast Mine

    Institute of Scientific and Technical Information of China (English)

    HAN Li-jun; BAI Zhong-ke; LI Jin-chuan

    2006-01-01

    A seed germinating method was used to study soil seed banks in dump sites of the Antaibao opencast mine for soil reclamation and ecological rehabilitation. Based on a richness index, a diversity index and an evenness index, the diversity of species of soil seed banks was studied. As well, the progress of vegetation succession in this thoroughly destroyed ecosystem is discussed and the self-renewal ability of the soil seed banks is analyzed. The results indicate that 1) there are 17 plant species belonging to five families with annuals as the dominant species; 2) the soil seed banks at the dump site show great temporal and spatial heterogeneity and 3) the model of Robinia pseudoacacia × Pinus tabulaeformis × Caragana korshinskii in the anaphase is the best among several reclamation models studied. Therefore, with the extension of reclamation time, the correct choice of a reclamation model is quite helpful for the improvement of the self-renewal ability of soil seed banks and for the stability of the ecosystem, which is very important for land reclamation and ecological rehabilitation of the dump sites of the ATB opencast coal mine.

  14. Ecological longevity of Polaskia chende (Cactaceae) seeds in the soil seed bank, seedling emergence and survival.

    Science.gov (United States)

    Ordoñez-Salanueva, C A; Orozco-Segovia, A; Canales-Martínez, M; Seal, C E; Pritchard, H W; Flores-Ortiz, C M

    2017-08-08

    Soil seed banks are essential elements of plant population dynamics, enabling species to maintain genetic variability, withstand periods of adversity and persist over time, including for cactus species. However knowledge of the soil seed bank in cacti is scanty. In this study, over a 5-year period we studied the seed bank dynamics, seedling emergence and nurse plant facilitation of Polaskia chende, an endemic columnar cactus of central Mexico. P. chende seeds were collected for a wild population in Puebla, Mexico. Freshly collected seeds were sown at 25 °C and 12-h photoperiod under white light, far-red light and darkness. The collected seeds were divided in two lots, the first was stored in the laboratory and the second was use to bury seeds in open areas and beneath a shrub canopy. Seeds were exhumed periodically over 5 years. At the same time seeds were sown in open areas and beneath shrub canopies; seedling emergence and survival were recorded over different periods of time for 5 years. The species forms long-term persistent soil seed banks. The timing of seedling emergence via germination in the field was regulated by interaction between light, temperature and soil moisture. Seeds entered secondary dormancy at specific times according to the expression of environmental factors, demonstrating irregular dormancy cycling. Seedling survival of P. chende was improved under Acacia constricta nurse plants. Finally, plant facilitation affected the soil seed bank dynamics as it promoted the formation of a soil seed bank, but not its persistence. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  15. Seed bank characteristics of Dutch plant communities

    NARCIS (Netherlands)

    Bekker, RM; Schaminee, JHJ; Bakker, JP; Thompson, K

    With the recent appearances of a new and well-documented classification of the Dutch plant communities (Schaminee et al 1995a,b; 1996) and a database on the seed longevity of plant species of North West Europe (Thompson ct al. 1997a) it was possible to investigate patterns of seed longevity in Dutch

  16. Seed bank characteristics of Dutch plant communities

    NARCIS (Netherlands)

    Bekker, RM; Schaminee, JHJ; Bakker, JP; Thompson, K

    1998-01-01

    With the recent appearances of a new and well-documented classification of the Dutch plant communities (Schaminee et al 1995a,b; 1996) and a database on the seed longevity of plant species of North West Europe (Thompson ct al. 1997a) it was possible to investigate patterns of seed longevity in Dutch

  17. Seed rain and seed bank reveal that seed limitation strongly influences plant community assembly in grasslands.

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    Bryndís Marteinsdóttir

    Full Text Available Dispersal is an important factor in plant community assembly, but assembly studies seldom include information on actual dispersal into communities, i.e. the local propagule pool. The aim of this study was to determine which factors influence plant community assembly by focusing on two phases of the assembly process: the dispersal phase and the establishment phase. At 12 study sites in grazed ex-arable fields in Sweden the local plant community was determined and in a 100-m radius around the centre of each site, the regional species pool was measured. The local seed bank and the seed rain was explored to estimate the local propagule pool. Trait-based models were then applied to investigate if species traits (height, seed mass, clonal abilities, specific leaf area and dispersal method and regional abundance influenced which species from the regional species pool, dispersed to the local community (dispersal phase and which established (establishment phase. Filtering of species during the dispersal phase indicates the effect of seed limitation while filtering during the establishment phase indicates microsite limitation. On average 36% of the regional species pool dispersed to the local sites and of those 78% did establish. Species with enhanced dispersal abilities, e.g. higher regional abundance, smaller seeds and dispersed by cattle, were more likely to disperse to the sites than other species. At half the sites, dispersal was influenced by species height. Species establishment was however mainly unlinked to the traits included in this study. This study underlines the importance of seed limitation in local plant community assembly. It also suggests that without information on species dispersal into a site, it is difficult to distinguish between the influence of dispersal and establishment abilities, and thus seed and microsite limitation, as both can be linked to the same trait.

  18. Grazing impact on desert plants and soil seed banks: Implications for seed-eating animals

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    Pol, Rodrigo G.; Sagario, M. Cecilia; Marone, Luis

    2014-02-01

    We assess whether the knowledge of livestock diet helps to link grazing effects with changes in plant cover and soil seed bank size, aiming at inferring the consequences of grazing on seed-eating animals. Specifically, we test whether continuous and heavy grazing reduce the cover, number of reproductive structures and seed reserves of the same grass species whose seeds are selected and preferred by granivorous animals in the central Monte desert, Argentina. Grass cover and the number of grass spikes usually diminished under grazing conditions in the two localities studied (Telteca and Ñacuñán), and soil seed bank was consistently reduced in all three years evaluated owing to a decline of perennial grass and forb seeds. In particular, the abundance of those seeds selected and preferred by birds and ants (in all cases grass species) declined 70-92% in Ñacuñán, and 52-72% in Telteca. Reduction of perennial grass cover and spike number in grazed sites reinforced the causal link between livestock grazing and the decline of grass soil seed reserves throughout failed plant reproduction. Grass seed bank depletion suggests that grazing may trigger a "cascade" of mechanisms that affect the abundance and persistence of valuable fodder species as well as the availability of seed resources for granivorous animals.

  19. ECOPHYSIOLOGICAL ANALYSIS OF GENIPA AMERICANA L. SEEDS IN AN INDUCED SOIL SEED BANK

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    Francesca Salla

    2016-03-01

    Full Text Available This work studied the behavior of G. americana L. (Rubiaceae seeds in an induced soil seed bank. This study was conducted in Lavras-MG in a seasonal semideciduous forest of the Federal University of Lavras. Seeds collected in the area were cleaned and analyzed (water content, viability and desiccation tolerance. Soil banks were installed in two distinct areas (top of hill and riparian forest located in the understory of the forest. Seeds were placed in nylon nets and covered with a thin litter layer that was previously removed for this purpose. Monthly assessment of germination, seedling emergence, seed and soil water content, and the characterization of the initial seedling growth was performed. It was observed that G. americana seeds forms a transitory seed bank, with maintenance of its viability until the fourth month after disposal in natural environment. In general, the seed bank located in the riparian forest area showed the best potential for seedling establishment in a natural environment, which supports the ecological behavior of this species.

  20. DORMANCY RELEASING MECHANISMS IN SOIL SEED BANKS OF Desmanthus GENOTYPES

    OpenAIRE

    JOSÉ HENRIQUE DE ALBUQUERQUE RANGEL; CHRISTOPHER PETER GARDINER; ROBERT LEWIS BURT

    2015-01-01

    Desmanthus is a genus of forage legumes with potential to improve pastures and livestock produc-tion on clay soils of dry tropical and subtropical regions such as the existing in Brazil and Australia. Despite this patterns of natural or enforced after-ripening of Desmanthus seeds have not been well established. Four year old seed banks of nine Desmanthus genotypes at James Cook University were accessed for their patterns of seed softe-ning in response to a range of temperatures. Persistent se...

  1. Striga hermonthica seed bank dynamics: process quantification and modelling

    NARCIS (Netherlands)

    Mourik, van T.A.

    2007-01-01

    Key words:    Weed control, integrated management, parasitic weed, population, sorghum, millet.   This thesis presents a study on the quantification of seed bank dynamics of the parasitic weed Striga hermonthica. The main objectives were to quantify transition rates between different stages of the

  2. Bancos de semillas en el suelo Soil seed banks

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    M. De Souza Maia

    2006-06-01

    Full Text Available En las comunidades vegetales, el banco de semillas en el suelo (BSS constituye el potencial regenerativo. La reposición de los individuos a partir del BSS puede tener un efecto marcado en la composición y en los patrones de vegetación de la comunidad. Numerosas investigaciones se han llevado a cabo en bancos de semillas en hábitats agrícolas o en comunidades naturales. Esta revisión tiene como objetivo analizar los conceptos relacionados a BSS, los procesos de formación de éstos, las implicancias agrícolas y cómo esta información puede ser usada para la conservación de los sistemas productivos.In plant communities, the soil seed bank (SSB represents their regenerative potential. The replacement of individuals from the seed bank may have profound effects on the composition and patterns of the vegetation within the community. Many investigations about seed banks have been made within agricultural habitats or in natural communities. The attempt of this review about the seed banks in the soil is to analyze the concepts related to SSBs, their formation, the agricultural implications and how this information might be used for the conservation of the productive systems.

  3. Seed bank response to prescribed fire in the central Appalachians.

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    Thomas M. Schuler; Melissa Thomas Van-Gundy; Mary B. Adams; W. Mark. Ford

    2010-01-01

    Pre- and post-treatment seed-bank characteristics of woody species were compared after two prescribed fires in a mesic mixed-oak forest in the central Appalachians. Nineteen woody species were identified from soil samples. Mean species richness declined but evenness did not after prescribed burning. The...

  4. New evidence for persistent or transient seed banks in three Sonoran Desert cacti

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    Bowers, Janice E.

    2005-01-01

    Seedlings of Ferocactus wislizeni and Mammillaria grahamii, 2 common cactus species in the northern Sonoran Desert, emerged under protective cages that had been left in place for 6 years after an initial sowing of numerous Carnegiea gigantea and F. wislizeni seeds. Because no seeds were sown in the interim, Mammillaria and Ferocactus seedlings must have emerged from persistent seed banks. Mammillaria seeds evidently survived in or on the soil as long as 6 years, forming a long-term persistent seed bank, and Ferocactus seeds apparently survived up to 3 years, forming a short-term persistent seed bank. No Carnegiea seedlings emerged, confirming that this species has a transient seed bank This is the first evidence for a between-year seed bank in M. grahamii and the first confirmation of a between-year seed bank in F. wislizeni.

  5. Big sagebrush seed bank densities following wildfires

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    Big sagebrush (Artemisia spp.) is a critical shrub to many wildlife species including sage grouse (Centrocercus urophasianus), mule deer (Odocoileus hemionus), and pygmy rabbit (Brachylagus idahoensis). Big sagebrush is killed by wildfires and big sagebrush seed is generally short-lived and do not s...

  6. Timing of seed dispersal generates a bimodal seed bank depth distribution

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    Espinar, J.L.; Thompson, K.; Garcia, L.V.

    2005-01-01

    The density of soil seed banks is normally highest at the soil surface and declines monotonically with depth. Sometimes, for a variety of reasons, peak density occurs below the surface but, except in severely disturbed soils, it is generally true that deeper seeds are older. In seasonally dry habitats that develop deep soil cracks during the dry season, it is possible that some seeds fall down cracks and rapidly become deeply buried. We investigated this possibility for three dominant clonal perennials (Scirpus maritimus, S. litoralis, and Juncus subulatus) in the Don??ana salt marsh, a nontidal marsh with a Mediterranean climate located in southwest Spain. Two species, which shed most of their seed during the dry season and have seeds with low buoyancy, had bimodal viable seed depth distributions, with peak densities at the surface and at 16-20 cm. A third species, which shed most seeds after soil cracks had closed and had seeds with high buoyancy, had viable seeds only in surface soil. Bimodal seed bank depth distributions may be relatively common in seasonally dry habitats with fine-textured soils, but their ecological significance has not been investigated.

  7. A seed bank pathogen causes seedborne disease: Pyrenophora semeniperda on undispersed grass seeds in western North America

    Science.gov (United States)

    Susan E. Meyer; Julie Beckstead; Phil S. Allen; Duane C. Smith

    2008-01-01

    The generalist pathogen Pyrenophora semeniperda is abundant in seed banks of the exotic winter annual grass Bromus tectorum in semiarid western North America and is also found in the seed banks of co-occurring native grasses. In this study, we examined natural incidence of disease caused by this pathogen on undispersed host seeds,...

  8. Similarity between seed bank and herb layer in a natural deciduous temperate lowland forest

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    Maciej Wódkiewicz

    2011-01-01

    Full Text Available Forest seed banks mostly studied in managed forests proved to be small, species poor and not reflecting aboveground species composition. Yet studies conducted in undisturbed communities indicate a different seed bank characteristic. Therefore we aimed at describing soil seed bank in an undisturbed forest in a remnant of European lowland temperate forests, the Białowieża Forest. We compared similarity between the herb layer and seed bank, similarity of seed bank between different patches, and dominance structure of species in the herb layer and in the seed bank of two related oak-hornbeam communities. We report relatively high values of Sorensen species similarity index between herb layer and seed bank of both patches. This suggests higher species similarity of the herb layer and soil seed bank in natural, unmanaged forests represented by both plots than in fragmented communities influenced by man. Although there was a set of core seed bank species present at both plots, yielding high Sorensen species similarity index values, considerable differences between plots in seed bank size and dominance structure of species were found, indicating spatial variability of studied seed bank generated by edaphic conditions. Dominance structure of species in the herb layer was not reflected in the underlying seed bank. This stresses, that natural forest regeneration cannot rely only on the seed bank, although some forest species are capable of forming soil seed banks. While forest seed banks may not reflect vegetation composition of past successional stages, they may inform on history and land use of a specific plot.

  9. Comparison of germination and seed bank dynamics of dimorphic seeds of the cold desert halophyte Suaeda corniculata subsp. mongolica.

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    Cao, Dechang; Baskin, Carol C; Baskin, Jerry M; Yang, Fan; Huang, Zhenying

    2012-12-01

    Differences in dormancy and germination requirements have been documented in heteromorphic seeds of many species, but it is unknown how this difference contributes to maintenance and regeneration of populations. The primary aim of this study was to compare the seed bank dynamics, including dormancy cycling, of the two seed morphs (black and brown) of the cold desert halophyte Suaeda corniculata and, if differences were found, to determine their influence on regeneration of the species. Seeds of the two seed morphs were buried, exhumed and tested monthly for 24 months over a range of temperatures and salinities, and germination recovery and viability were determined after exposure to salinity and water stress. Seedling emergence and dynamics of the soil seed bank were also investigated for the two morphs. Black seeds had an annual dormancy/non-dormancy cycle, while brown seeds, which were non-dormant at maturity, remained non-dormant. Black seeds also exhibited an annual cycle in sensitivity of germination to salinity. Seedlings derived from black seeds emerged in July and August and those from brown seeds in May. Seedlings were recruited from 2·6 % of the black seeds and from 2·8 % of the brown seeds in the soil, and only 0·5 % and 0·4 % of the total number of black and brown seeds in the soil, respectively, gave rise to seedlings that survived to produce seeds. Salinity and water stress induced dormancy in black seeds and decreased viability of brown seeds. Brown seeds formed only a transient soil seed bank and black seeds a persistent seed bank. The presence of a dormancy cycle in black but not in brown seeds of S. corniculata and differences in germination requirements of the two morphs cause them to differ in their germination dynamics. The study contributes to our limited knowledge of dormancy cycling and seed bank formation in species producing heteromorphic seeds.

  10. Comparison of germination and seed bank dynamics of dimorphic seeds of the cold desert halophyte Suaeda corniculata subsp. mongolica

    Science.gov (United States)

    Cao, Dechang; Baskin, Carol C.; Baskin, Jerry M.; Yang, Fan; Huang, Zhenying

    2012-01-01

    Background and Aims Differences in dormancy and germination requirements have been documented in heteromorphic seeds of many species, but it is unknown how this difference contributes to maintenance and regeneration of populations. The primary aim of this study was to compare the seed bank dynamics, including dormancy cycling, of the two seed morphs (black and brown) of the cold desert halophyte Suaeda corniculata and, if differences were found, to determine their influence on regeneration of the species. Method Seeds of the two seed morphs were buried, exhumed and tested monthly for 24 months over a range of temperatures and salinities, and germination recovery and viability were determined after exposure to salinity and water stress. Seedling emergence and dynamics of the soil seed bank were also investigated for the two morphs. Key Results Black seeds had an annual dormancy/non-dormancy cycle, while brown seeds, which were non-dormant at maturity, remained non-dormant. Black seeds also exhibited an annual cycle in sensitivity of germination to salinity. Seedlings derived from black seeds emerged in July and August and those from brown seeds in May. Seedlings were recruited from 2·6 % of the black seeds and from 2·8 % of the brown seeds in the soil, and only 0·5 % and 0·4 % of the total number of black and brown seeds in the soil, respectively, gave rise to seedlings that survived to produce seeds. Salinity and water stress induced dormancy in black seeds and decreased viability of brown seeds. Brown seeds formed only a transient soil seed bank and black seeds a persistent seed bank. Conclusions The presence of a dormancy cycle in black but not in brown seeds of S. corniculata and differences in germination requirements of the two morphs cause them to differ in their germination dynamics. The study contributes to our limited knowledge of dormancy cycling and seed bank formation in species producing heteromorphic seeds. PMID:22975287

  11. Supplementing seed banks to rehabilitate disturbed Mojave Desert shrublands: where do all the seeds go?

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    DeFalco, Lesley A.; Esque, Todd C.; Nicklas, Melissa B.; Kane, Jeffrey M.

    2012-01-01

    Revegetation of degraded arid lands often involves supplementing impoverished seed banks and improving the seedbed, yet these approaches frequently fail. To understand these failures, we tracked the fates of seeds for six shrub species that were broadcast across two contrasting surface disturbances common to the Mojave Desert—sites compacted by concentrated vehicle use and trenched sites where topsoil and subsurface soils were mixed. We evaluated seedbed treatments that enhance soil-seed contact (tackifier) and create surface roughness while reducing soil bulk density (harrowing). We also explored whether seed harvesting by granivores and seedling suppression by non-native annuals influence the success of broadcast seeding in revegetating degraded shrublands. Ten weeks after treatments, seeds readily moved off of experimental plots in untreated compacted sites, but seed movements were reduced 32% by tackifier and 55% through harrowing. Harrowing promoted seedling emergence in compacted sites, particularly for the early-colonizing species Encelia farinosa, but tackifier was largely ineffective. The inherent surface roughness of trenched sites retained three times the number of seeds than compacted sites, but soil mixing during trench development likely altered the suitability of the seedbed thus resulting in poor seedling emergence. Non-native annuals had little influence on seed fates during our study. In contrast, the prevalence of harvester ants increased seed removal on compacted sites, whereas rodent activity influenced removal on trenched sites. Future success of broadcast seeding in arid lands depends on evaluating disturbance characteristics prior to seeding and selecting appropriate species and seasons for application.

  12. Banking on the Future. Seed Bank Investigations Teach Biodiversity and Biocomplexity

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2013-01-01

    People depend on plants to fulfill many of their basic needs, such as food, clothing, and shelter. Although plants are all around us, people are often afflicted with "plant blindness," paying more attention to animals (Wandersee and Clary 2006; Wandersee and Schussler 2001). Studying seed banks and building one in the classroom can…

  13. Banking on the Future. Seed Bank Investigations Teach Biodiversity and Biocomplexity

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2013-01-01

    People depend on plants to fulfill many of their basic needs, such as food, clothing, and shelter. Although plants are all around us, people are often afflicted with "plant blindness," paying more attention to animals (Wandersee and Clary 2006; Wandersee and Schussler 2001). Studying seed banks and building one in the classroom can…

  14. Tillage and residue burning affects weed populations and seed banks.

    Science.gov (United States)

    Narwal, S; Sindel, B M; Jessop, R S

    2006-01-01

    An integrated weed management approach requires alternative management practices to herbicide use such as tillage, crop rotations and cultural controls to reduce soil weed seed banks. The objective of this study was to examine the value of different tillage practices and stubble burning to exhaust the seed bank of common weeds from the northern grain region of Australia. Five tillage and burning treatments were incorporated in a field experiment, at Armidale (30 degrees 30'S, 151 degrees 40'E), New South Wales, Australia in July 2004 in a randomized block design replicated four times. The trial was continued and treatments repeated in July 2005 with all the mature plants from the first year being allowed to shed seed in their respective treatment plots. The treatments were (i) no tillage (NT), (ii) chisel ploughing (CP), (iii) mould board ploughing (MBP), (iv) wheat straw burning with no tillage (SBNT) and (v) wheat straw burning with chisel ploughing (SBC). Soil samples were collected before applying treatments and before the weeds flowered to establish the seed bank status of the various weeds in the soil. Wheat was sown after the tillage treatments. Burning treatments were only initiated in the second year, one month prior to tillage treatments. The major weeds present in the seed bank before initiating the trial were Polygonum aviculare, Sonchus oleraceus and Avena fatua. Tillage promoted the germination of other weeds like Hibiscus trionum, Medicago sativa, Vicia sp. and Phalaris paradoxa later in the season in 2004 and Convolvulus erubescens emerged as a new weed in 2005. The MBP treatment in 2004 reduced the weed biomass to a significantly lower level of 55 g/m2 than the other treatments of CP (118 g/m2) and NT plots (196 g/m2) (P < 0.05). However, in 2005 SBC and MBP treatments were similar in reducing the weed biomass. In 2004, the grain yield trend of wheat was significantly different between CP and NT, and MBP and NT (P < 0.05) with maximum yield of 5898

  15. Characteristics of soil seed bank in plantation forest in the rocky mountain region of Beijing, China

    Institute of Scientific and Technical Information of China (English)

    HU Zeng-hui; YANG Yang; LENG Ping-sheng; DOU De-quan; ZHANG Bo; HOU Bing-fei

    2013-01-01

    We investigated characteristics (scales and composition) of soil seed banks at eight study sites in the rocky mountain region of Beijing by seed identification and germination monitoring.We also surveyed the vegetation communities at the eight study sites to explore the role of soil seed banks in vegetation restoration.The storage capacity of soil seed banks at the eight sites ranked from 766.26 to 2461.92 seedsm-2.A total of 23 plant species were found in soil seed banks,of which 63-80%of seeds were herbs in various soil layers and 60% of seeds were located in the soil layer at 0-5 cm depth.Biodiversity indices indicated clear differences in species diversity of soil seed banks among different plant communities.The species composition of aboveground vegetation showed low similarity with that based on soil seed banks.In the aboveground plant community,the afforestation tree species showed high importance values.The plant species originating from soil seed banks represented natural regeneration,which also showed relatively high importance values.This study suggests that in the rocky mountain region of Beijing the soil seed banks played a key role in the transformation from pure plantation forest to near-natural forest,promoting natural ecological processes,and the role of the seed banks in vegetation restoration was important to the improvement of ecological restoration methods.

  16. The ancestral process of long term seed bank models

    CERN Document Server

    Blath, Jochen; Kurt, Noemi; Spanò, Dario

    2012-01-01

    We present a new model for the evolution of genetic types in the presence of so-called seed banks, i.e., where individuals may obtain their genetic type from ancestors which have lived in the near as well as the very far past. The classical Wright-Fisher model, as well as a seed bank model with bounded age distribution considered by Kaj, Krone and Lascoux (2001) are special cases of our model. We discern three parameter regimes of the seed bank age distribution, which lead to substantially different behaviour in terms of genetic variability, in particular with respect to fixation of types and time to the most recent common ancestor. We prove that for age distributions with finite mean, the rescaled ancestral process converges to a time-changed Kingman coalescent, while in the case of infinite mean, ancestral lineages might not merge at all with positive probability. Further, we present a construction of the forward in time process in equilibrium. The mathematical methods are based on renewal theory, the urn p...

  17. The seed bank of a gallery forest in Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Maria Tereza Grombone-Guaratini

    2004-09-01

    Full Text Available The soil seed bank was studied in a gallery forest in Southeastern Brazil. Samples were collected from edge to edge along transects perpendicular to the river during the wet (December, 1990 and dry (August, 1991 seasons. The number of seeds found in the seed bank samples was greater in the dry season than in the wet season indicating that there was important variation in the seed stocks in these two periods. The similarity values between the seed bank and the community composition were low. The high density of weed species might be reflecting forest fragmentation and indicating a degree of perturbation.O banco de sementes do solo foi estudado em uma floresta de galeria. As amostras de banco de sementes foram coletadas ao longo de transectos abertos perpendicularmente à área do rio durante as estações chuvosa (dezembro/1990 e seca (agosto/1991. O número de sementes encontrado nas amostras de banco de sementes proveniente da estação seca foi significativamente maior do que o número de sementes encontrado nas amostras provenientes da estação chuvosa. Os resultados obtidos evidenciaram uma variação significativa entre o estoque de sementes encontrados nos dois períodos amostrados. A similaridade entre o estoque de sementes no solo e a flora local foi baixa. A alta densidade de espécies invasoras pode refletir a fragmentação e indicar o grau de perturbação da floresta.

  18. Response of drought and fertilization in Erica andevalensis seed banks: significance for conservation management.

    Science.gov (United States)

    Rossini Oliva, S; Mingorance, M D

    2012-11-30

    The present study attempts to investigate the size, composition and seedling dynamics of the seed bank of a metalliferous and vulnerable species, Erica andevalensis. Samples were taken during spring and autumn from two different sites. We also studied the effects of nutrient solution, irrigation from the river Tinto and irrigation deficit on seeding establishment and survival. Only E. andevalensis and Poaceae species emerged from the seed banks, although the former was dominant (98%). Germination and seedling establishment was totally inhibited by the waters of the river Tinto. Seed density was high in the soils of both seed banks irrigated with water and nutrient solution. We found no seasonal differences in the seed bank and number of germinated seeds and mortality rate and density were similar. From the standpoint of restoration management, the results indicate that the seed bank is a very important factor for successful species establishment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Disturbance frequency and vertical distribution of seeds affect long-term population dynamics: a mechanistic seed bank model.

    Science.gov (United States)

    Eager, Eric Alan; Haridas, Chirakkal V; Pilson, Diana; Rebarber, Richard; Tenhumberg, Brigitte

    2013-08-01

    Seed banks are critically important for disturbance specialist plants because seeds of these species germinate only in disturbed soil. Disturbance and seed depth affect the survival and germination probability of seeds in the seed bank, which in turn affect population dynamics. We develop a density-dependent stochastic integral projection model to evaluate the effect of stochastic soil disturbances on plant population dynamics with an emphasis on mimicking how disturbances vertically redistribute seeds within the seed bank. We perform a simulation analysis of the effect of the frequency and mean depth of disturbances on the population's quasi-extinction probability, as well as the long-term mean and variance of the total density of seeds in the seed bank. We show that increasing the frequency of disturbances increases the long-term viability of the population, but the relationship between the mean depth of disturbance and the long-term viability of the population are not necessarily monotonic for all parameter combinations. Specifically, an increase in the probability of disturbance increases the long-term viability of the total seed bank population. However, if the probability of disturbance is too low, a shallower mean depth of disturbance can increase long-term viability, a relationship that switches as the probability of disturbance increases. However, a shallow disturbance depth is beneficial only in scenarios with low survival in the seed bank.

  20. Soil seed banks Banco de sementes do solo

    Directory of Open Access Journals (Sweden)

    P.J. Christoffoleti

    1998-01-01

    Full Text Available The goal of this literature review is to discuss some of the major aspects of the soil seed bank, from its characteristics down to methodological aspects of its determination. Soil seed bank is the reservoir of viable seeds or of vegetative propagules that are present in the soil and that are able to recompose a natural vegetation. In the agroecossystems the soil seed bank is related to weeds, and the knowledge of its size and composition in terms of species can be used in the prediction of future infestations, to built simulation models of population establishment through time and also the definition of soil and cultural management programs, in order to have a rational use of herbicides.O objetivo desta revisão é discorrer sobre alguns pontos importantes no estudo do banco de sementes no solo, desde as sua características até aspectos metodológicos para sua determinação. Denomina-se de banco de sementes a reserva destas ou de propágulos vegetativos viáveis presentes no solo e que são capazes de recompor uma vegetação. Nos sistemas agrícolas o banco está relacionado com o estudo das plantas daninhas; o conhecimento do seu tamanho e das espécies que o compõem poderá ser utilizado na previsão de infestações futuras, na construção de modelos de estabelecimentos populacionais no tempo e consequentemente na definição de programas de manejo de solo e culturais, visando racionalizar a utilização de herbicidas.

  1. [Soil seed bank research of China mining areas: necessity and challenges].

    Science.gov (United States)

    Chang, Qing; Zhang, Da-Wei; Li, Xue; Peng, Jian; Guan, Ai-Nong; Liu, Xiao-Si

    2011-05-01

    Soil seed bank consists of all living seeds existed in soil and its surface litter, especially in topsoil, and can reflect the characteristics of regional biodiversity. As the base of vegetation restoration and potential greening material, topsoil and its seed bank are the limited and non-renewable resources in mining areas. The study of soil seed bank has become one of the hotspots in the research field of vegetation restoration and land reclamation in China mining areas. Owing to the special characteristics of mining industry, the soil seed bank study of mining areas should not only concern with the seed species, quantities, and their relations with ground surface vegetation, but also make use of the research results on the soil seed bank of other fragile habitats. Besides, a breakthrough should be sought in the thinking ways and research approach. This paper analyzed the particularity of mining area's soil seek bank research, summarized the research progress in the soil seed bank of mining areas and other fragile habitats, and put forward the challenges we are facing with. It was expected that this paper could help to reinforce the soil seed bank research of China mining areas, and provide scientific guidelines for taking great advantage of the significant roles of soil seed bank in land reclamation and vegetation restoration in the future.

  2. Supplementing seed banks to rehabilitate disturbed Mojave Desert shrublands: Where do all the seeds go?

    Science.gov (United States)

    DeFalco, L.A.; Esque, T.C.; Nicklas, M.B.; Kane, J.M.

    2012-01-01

    Revegetation of degraded arid lands often involves supplementing impoverished seed banks and improving the seedbed, yet these approaches frequently fail. To understand these failures, we tracked the fates of seeds for six shrub species that were broadcast across two contrasting surface disturbances common to the Mojave Desert-sites compacted by concentrated vehicle use and trenched sites where topsoil and subsurface soils were mixed. We evaluated seedbed treatments that enhance soil-seed contact (tackifier) and create surface roughness while reducing soil bulk density (harrowing). We also explored whether seed harvesting by granivores and seedling suppression by non-native annuals influence the success of broadcast seeding in revegetating degraded shrublands. Ten weeks after treatments, seeds readily moved off of experimental plots in untreated compacted sites, but seed movements were reduced 32% by tackifier and 55% through harrowing. Harrowing promoted seedling emergence in compacted sites, particularly for the early-colonizing species Encelia farinosa, but tackifier was largely ineffective. The inherent surface roughness of trenched sites retained three times the number of seeds than compacted sites, but soil mixing during trench development likely altered the suitability of the seedbed thus resulting in poor seedling emergence. Non-native annuals had little influence on seed fates during our study. In contrast, the prevalence of harvester ants increased seed removal on compacted sites, whereas rodent activity influenced removal on trenched sites. Future success of broadcast seeding in arid lands depends on evaluating disturbance characteristics prior to seeding and selecting appropriate species and seasons for application. ?? 2010 Society for Ecological Restoration International.

  3. The influence of substrates rates on the germination characteristic of a soil seed bank

    Science.gov (United States)

    Zhao, N.; He, M. X.; Li, H. Y.; Meng, W. Q.

    2016-08-01

    Soil seed bank (SSB) is considered as an important way of vegetation restoration, it can fleetly achieved vegetation diversification and the course of succession when the topsoil mixed with planting substrates. In this paper, a greenhouse germination method was used to explore the effect on germination characteristic of soil seed bank by adding different inorganic substrates, such as activated carbon, perlite and vermiculite. The results showed that perlite and vermiculite can effectively promote the germination of soil seed bank, but also significantly promote Shannon-Wiener diversity index. When vermiculite mixed with the topsoil in 40%, the germination effect of soil seed bank was more obviously than other groups; at this time, the density of soil seed bank reached 6 X 105 plants/m2 , Shannon Wiener diversity index reached 1.4354. Therefore, it was more conducive to improve the soil seed bank density and species diversity by adding 40% vermiculite in the topsoil.

  4. Of what value is the soil seed bank for minesite rehabilitation in Queensland?

    Energy Technology Data Exchange (ETDEWEB)

    Bellairs, S.M. [University of Queensland, St Lucia, Qld. (Australia). Dept. of Agriculture and Centre for Mined Land Rehabilitation

    1997-06-01

    This paper provides an overview of research carried out on soil seed banks in relation to minesite rehabilitation in Queensland. Quantitative studies of the soil bank have been carried out at several sites including: prior to mineral sand mining on North Stradbroke Island, the Blair Athol, Curragh and Newlands open-cut coal mines in central Queensland, and the Tarong Coal mine in southeast Queensland. The size of the germinable seed bank in the surface few centimetres of topsoil ranged considerably, from less than 20 to greater than 2,000 seeds per square metre. There was as much variation between different vegetation types at the same minesite as between sites. Where the seed bank was large, it tended to consist of grasses or other monocotyledons, and fewer seeds were present in communities with more substantial tree and shrub strata. The contribution of the soil seed bank relative to the broadcast seed mix is also discussed. 22 refs., 3 tabs.

  5. Soil seed banks confer resilience to savanna grass-layer plants during seasonal disturbance

    Science.gov (United States)

    Scott, Kenneth; Setterfield, Samantha; Douglas, Michael; Andersen, Alan

    2010-03-01

    An understanding of soil seed bank processes is crucial for understanding vegetation dynamics, particularly in ecosystems experiencing frequent disturbance. This paper examines seed bank dynamics in a tropical savanna in northern Australia, an environment characterised by frequent fire and highly seasonal rainfall. In particular, we examine the contribution of seed bank processes to the high level of resilience shown by grass-layer vegetation in relation to fire. We assess the spatial congruence between seed bank composition and extant vegetation, document temporal variation in the germinable seed bank over the annual dry season, test the effects of laboratory-applied heat and smoke treatments on seed germinability, and determine the effect of experimental fires on seed bank composition. Although dominant species were shared, the composition of the germinable seed bank was significantly different to that of extant vegetation, with approximately half the extant species not being detected in the seed bank. The density and species richness of germinable seeds was significantly greater in the late dry season than the early dry season, with annual grasses showing particularly high levels of seed dormancy in the early dry season. The density and species richness of germinable seeds in the seed bank was significantly enhanced by laboratory-applied treatments of smoke and especially heat, driven by the response of legumes. However, fire had no significant effect on the density or species richness of germinable seeds in the field, indicating soil temperatures during fire were too low to overcome physical dormancy, or burial was too deep to experience adequate heating or smoke exposure. Our results provide a mechanistic understanding of the persistence of annual grasses and forbs in an environment subject to frequent fire and highly seasonal rainfall, and, together with the sprouting capacity of perennial grasses, explain the high resilience of savanna grass-layer plants in

  6. Rapid and High Seed Germination and Large Soil Seed Bank of Senecio aquaticus in Managed Grassland

    Directory of Open Access Journals (Sweden)

    Matthias Suter

    2012-01-01

    Full Text Available Senecio aquaticus, regionally a Red List species in Europe, has become increasingly abundant in agricultural grassland of medium to high management intensity in Switzerland, Southern Germany, and Austria in recent years, where it is a threat for animal and human health due to its toxicity. In this study, we investigated the seed ecology of S. aquaticus to help protection of the species in relic populations while improving its control when abundant in managed grassland. Germination percentages of fresh ripe seeds of S. aquaticus were on average 68% in 2008, but only 45% in 2010, indicating yearly variation. Germination was generally fast: ten days after the onset of the tests, often more than 45% of all seeds had germinated. When covered with a soil layer of 5 mm, germination was only 16% compared to 63% in full light. Seeds buried in the soil for one and two years showed a germination of 78%, significantly higher than that of fresh ripe seeds, thus suggesting a stimulating effect of cold-wet stratification on germination and long seed survival in the soil. In grasslands with established populations of S. aquaticus, the number of germinable seeds of the species ranged from 361 to 1875 m-2 in topsoil (0–10 cm with an average of 1139 m-2. The large seed bank and the rapid and high germination of S. aquaticus suggest that allowing seed formation is important for its preservation in relic populations. With respect to agricultural grassland, strategies to control the species should initially target hindering seed production and dispersal.

  7. Adventitious presence of other varieties in oilseed rape (¤Brassica napus¤) from seed banks and certified seed

    DEFF Research Database (Denmark)

    Jørgensen, T.; Hauser, Thure Pavlo; Bagger Jørgensen, Rikke

    2007-01-01

    To obtain information on possible sources of contamination of the seed harvest of oilseed rape (Brassica napus L., spp. napus) by other varieties (adventitious presence), we investigated the purity of certified seed lots; the abundance and origin of volunteers; and longevity and origin of seeds...... in the soil seed-bank. This information was acquired through DNA analysis of volunteers collected in the field and seedlings derived from the soil seed-bank. DNA profiles of the volunteers and seedlings were obtained using Inter Simple Sequence Repeat (ISSR) markers, and the profiles were compared with ISSR...... profiles from an assortment of 14 of the most commonly cultivated oilseed rape varieties from 1985 to 2004. This comparison was performed using the assignment program, AFLPOP. The age of the seed bank germinating to become volunteers was assumed from information on previously cultivated oilseed rape...

  8. Aerial and soil seed banks enable populations of an annual species to cope with an unpredictable dune ecosystem

    Science.gov (United States)

    Gao, Ruiru; Yang, Xuejun; Yang, Fan; Wei, Lingling; Huang, Zhenying; Walck, Jeffrey L.

    2014-01-01

    Background and Aims Simultaneous formation of aerial and soil seed banks by a species provides a mechanism for population maintenance in unpredictable environments. Eolian activity greatly affects growth and regeneration of plants in a sand dune system, but we know little about the difference in the contributions of these two seed banks to population dynamics in sand dunes. Methods Seed release, germination, seedling emergence and survival of a desert annual, Agriophyllum squarrosum (Chenopodiaceae), inhabiting the Ordos Sandland in China, were determined in order to explore the different functions of the aerial and soil seed banks. Key Results The size of the aerial seed bank was higher than that of the soil seed bank throughout the growing season. Seed release was positively related to wind velocity. Compared with the soil seed bank, seed germination from the aerial seed bank was lower at low temperature (5/15 °C night/day) but higher in the light. Seedling emergence from the soil seed bank was earlier than that from the aerial seed bank. Early-emerged (15 April–15 May) seedlings died due to frost, but seedlings that emerged during the following months survived to reproduce successfully. Conclusions The timing of seed release and different germination behaviour resulted in a temporal heterogeneity of seedling emergence and establishment between the two seed banks. The study suggests that a bet-hedging strategy for the two seed banks enables A. squarrosum populations to cope successfully with the unpredictable desert environment. PMID:24918206

  9. Impact of land use type on soil seed bank flora in Chilimo Forest ...

    African Journals Online (AJOL)

    Impact of land use type on soil seed bank flora in Chilimo Forest, Ethiopia: Implications ... Ethiopian Journal of Biological Sciences ... in ten habitat types (10 plots in each) for the collection of data on the soil seed bank and standing vegetation.

  10. Analysis of plant soil seed banks and seed dispersal vectors: Its potential and limits for forensic investigations.

    Science.gov (United States)

    Šumberová, Kateřina; Ducháček, Michal

    2017-01-01

    Plant seeds exhibit many species-specific traits, thus potentially being especially helpful for forensic investigations. Seeds of a broad range of plant species occur in soil seed banks of various habitats and may become attached in large quantities to moving objects. Although plant seeds are now routinely used as trace evidence in forensic practice, only scant information has been published on this topic in the scientific literature. Thus, the standard methods remain unknown to specialists in such botanical subjects as plant ecology and plant geography. These specialists, if made aware of the forensic uses of seeds, could help in development of new, more sophisticated approaches. We aim to bridge the gap between forensic analysts and botanists. Therefore, we explore the available literature and compare it with our own experiences to reveal both the potential and limits of soil seed bank and seed dispersal analysis in forensic investigations. We demonstrate that habitat-specific and thus relatively rare species are of the greatest forensic value. Overall species composition, in terms of species presence/absence and relative abundance can also provide important information. In particular, the ecological profiles of seeds found on any moving object can help us identify the types of environments through which the object had travelled. We discuss the applicability of this approach to various European environments, with the ability to compare seed samples with georeferenced vegetation databases being particularly promising for forensic investigations. We also explore the forensic limitations of soil seed bank and seed dispersal vector analyses.

  11. Behind the Public Face of Kew: Education and Conservation in the Millennium Seed Bank

    Science.gov (United States)

    McFarlane, Angela

    2010-01-01

    At its Wakehurst Place garden in West Sussex, the Royal Botanic Gardens, Kew, has established the UK home of one of the world's largest conservation projects, the Millennium Seed Bank (MSB) partnership, a global project to conserve biodiversity by collecting and preserving seeds. This article describes what the MSB partnership does, how seeds are…

  12. Behind the Public Face of Kew: Education and Conservation in the Millennium Seed Bank

    Science.gov (United States)

    McFarlane, Angela

    2010-01-01

    At its Wakehurst Place garden in West Sussex, the Royal Botanic Gardens, Kew, has established the UK home of one of the world's largest conservation projects, the Millennium Seed Bank (MSB) partnership, a global project to conserve biodiversity by collecting and preserving seeds. This article describes what the MSB partnership does, how seeds are…

  13. Seed Dynamics in Relation to Gaps in a Tropical Montane Rainforest of Hainan Island, South China: (Ⅱ) Seed Bank

    Institute of Scientific and Technical Information of China (English)

    Run-Guo Zang; Yi Ding; Wei-Yin Zhang

    2008-01-01

    Spatial and temporal patterns of seed bank dynamics In relation to gaps in an old growth tropical montane rainforast of Hainan Island, South China, were studied over two consecutive years. From June 2001 to June 2003, soil seed bank sampling blocks were taken near each of the four sides of each seed trap and immediately put into a nursery for observation of seedling emergence dynamics in four seasons (each experiment in each season). The abundances of seedlings that emerged from seed banks showed the trend of vine functional group (VFG) > shrub functional group (SFG) > tree functional group (TFG) > herb functional group (HFG), but the trend in species richness of seedlings that emerged from the soil seed banks was TFG > VFG > SFG > HFG. The abundances of seedlings that emerged from seed banks in the three gap zones showed no significant differences, but significant differences did exist for the species richness. The time of sampling or seasons of experiments had significant influences on both the species richness and seedling abundances. The seedling emergence processes of each experiment all revealed the unimodal patterns. Few emergences occurred 1 year after each experiment. Compared with those under closed canopies, the recruitment rates from seed to seedlings and from seedlings to saplings in gaps were higher, but the mortality rates from saplings to big trees were also higher in the gaps.

  14. Seed bank and big sagebrush plant community composition in a range margin for big sagebrush

    Science.gov (United States)

    Martyn, Trace E.; Bradford, John B.; Schlaepfer, Daniel R.; Burke, Ingrid C.; Laurenroth, William K.

    2016-01-01

    The potential influence of seed bank composition on range shifts of species due to climate change is unclear. Seed banks can provide a means of both species persistence in an area and local range expansion in the case of increasing habitat suitability, as may occur under future climate change. However, a mismatch between the seed bank and the established plant community may represent an obstacle to persistence and expansion. In big sagebrush (Artemisia tridentata) plant communities in Montana, USA, we compared the seed bank to the established plant community. There was less than a 20% similarity in the relative abundance of species between the established plant community and the seed bank. This difference was primarily driven by an overrepresentation of native annual forbs and an underrepresentation of big sagebrush in the seed bank compared to the established plant community. Even though we expect an increase in habitat suitability for big sagebrush under future climate conditions at our sites, the current mismatch between the plant community and the seed bank could impede big sagebrush range expansion into increasingly suitable habitat in the future.

  15. Seed rain, soil seed bank, seed loss and regeneration of Castanopsis fargesii (Fagaceae) in a subtropical evergreen broad-leaved forest

    Science.gov (United States)

    Du, X.; Guo, Q.; Gao, X.; Ma, K.

    2007-01-01

    Understanding the seed rain and seed loss dynamics in the natural condition has important significance for revealing the natural regeneration mechanisms. We conducted a 3-year field observation on seed rain, seed loss and natural regeneration of Castanopsis fargesii Franch., a dominant tree species in evergreen broad-leaved forests in Dujiangyan, southwestern China. The results showed that: (1) there were marked differences in (mature) seed production between mast (733,700 seeds in 2001) and regular (51,200 and 195,600 seeds in 2002 and 2003, respectively) years for C. fargesii. (2) Most seeds were dispersed in leaf litter, humus and 0-2 cm depth soil in seed bank. (3) Frequency distributions of both DBH and height indicated that C. fargesii had a relatively stable population. (4) Seed rain, seed ground density, seed loss, and leaf fall were highly dynamic and certain quantity of seeds were preserved on the ground for a prolonged time due to predator satiation in both the mast and regular years so that the continuous presence of seed bank and seedling recruitments in situ became possible. Both longer time observations and manipulative experiments should be carried out to better understand the roles of seed dispersal and regeneration process in the ecosystem performance. ?? 2006 Elsevier B.V. All rights reserved.

  16. Resilience of invaded riparian landscapes: the potential role of soil-stored seed banks.

    Science.gov (United States)

    Tererai, Farai; Gaertner, Mirijam; Jacobs, Shayne M; Richardson, David M

    2015-01-01

    We investigated the potential role of soil-stored seed banks in driving vegetation recovery under varying intensities of invasion by the alien tree Eucalyptus camaldulensis along the Berg River in South Africa's Western Cape Province. We asked: How do richness, diversity, and composition of soil-stored seed banks vary with invasion intensity? What is the difference between the seed banks and above-ground vegetation with respect to species richness, diversity, composition, and structure? To what extent do soil-stored seed banks provide reliable sources for restoring native plant communities? Through a seedling-emergence approach, we compared seedling density, richness, and diversity in plots under varying Eucalyptus cover. Seed bank characteristics were also compared with those of the above-ground vegetation. Except in terms of diversity and density, the richness and composition of native species varied significantly among invasion conditions. Despite the paucity of native tree and shrub species in the seed bank, it was more diverse than extant vegetation. Some species occurred exclusively either in the seed bank or in the above-ground vegetation. Although this ecosystem has been degraded by several agents, including Eucalyptus invasion, soil-stored seed banks still offer modest potential for driving regeneration of native plant communities, but secondary invasions need to be managed carefully. Remnant populations of native plants in the above-ground vegetation remaining after E. camaldulensis clearing provide a more promising propagule source for rapid regeneration. Further work is needed to elucidate possible effects of invasion on successional pathways following E. camaldulensis removal and the effects of hydrochory on seed bank dynamics.

  17. Soil seed-bank germination patterns in natural pastures under different mineral fertilizer treatments

    Directory of Open Access Journals (Sweden)

    Anna Iannucci

    2014-11-01

    Full Text Available Degraded native grasslands in Mediterranean areas can be improved by encouraging seedling regeneration from soil seed banks using chemical fertilization. The effect of mineral fertilizers on soil seed banks was studied in natural pastures at two locations in southern Italy: Carpino and Rignano Garganico. The aim was to determine if nitrogen (N, phosphorus (P and combined nitrogen and phosphorus (NP fertilization can promote increased soil seed density. The seed-bank size and composition were analysed over two growth cycles (2004-2006 at two periods of the year: at the early summer and at the early autumn. The plant species were classified into three functional groups: grasses, legumes and other species (all other dicots. A two-pool model (ephemeral and base pools derived from the germination patterns was developed to quantify the dynamics of the germinated seed populations. The mean total seed number in the seed bank ranged from 2,915 to 4,782 seed m-2 with higher values in early summer than in early autumn. Mineral fertilizer applications increased the seed-bank size (by 27%, 23% and 46%, for N, P and NP, respectively and modified the composition in both localities. The three plant functional groups showed different potentials for ephemeral and persistent seed-bank production; however, within each plant group, the proportion between the ephemeral and base pool fractions did not change with fertilizer application. These data show that mineral fertilization can have positive effects on the seed-bank size of ungrazed natural pastures, and can be used to improve degraded Mediterranean pastures.

  18. El Niño effects on soil seed bank dynamics in north-central Chile.

    Science.gov (United States)

    Gutiérrez, Julio R; Meserve, Peter L

    2003-03-01

    The soil seed bank was monitored in four 75x75 m plots over 6 years (1990-1995) in an arid thorn scrub community in north-central Chile. Sixty-six species were identified. Total seed densities ranged from 2,000 to 42,000/m(2). Average mass of shrub seeds was significantly greater than that of other growth-forms. Between 70 and 90% of the seeds were less than 1 mg, with those in the 0.51-1.00 mg size class being most numerous. Seed densities were highly variable between years as well as within years, but were also closely associated with plant cover patterns and rainfall regime. Higher seed densities were found in wet years, and in samples taken in early summer and early autumn (i.e., after seed set); the lowest seed densities were in late winter (i.e., after annual plant germination). The annual plant species with the highest cover were also the most abundant in the soil seed bank and exhibited the largest seed density fluctuations. In general, seed densities were 5- to 10-fold higher during the 1991-1992 El Niño/southern oscillation (ENSO) years than non-ENSO years, showing the importance of this phenomenon for seed bank replenishment in the arid region of Chile.

  19. Spatial variation of seed rain and seed banks in gaps of karst forest in the Maolan Nature Reserve, Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    Cuiling LONG; Shixiao YU

    2008-01-01

    Based on an investigation on gaps and non-gap stands of the Maolan National Karst Forest Nature Reserve, Guizhou Province, quantitative characteristics and dynamic changes of seed rain and seed banks in gaps were analyzed. The results show that the total amount of seed rain was 117.4 ± 32.6 seeds/m2 during the period of observation. The number of immature seeds was 56.3 ± 10.3 seeds/m2, that of mature damaged seeds was 15.7 ± 4.7 seeds/m2, and the number of mature germinated seeds was 45.4 ± 8.2 seeds/m2 It is suggested that the seed number is rich for gap regeneration. Seed rain in gaps has spatial and temporal heterogeneities which deeply affect regeneration patterns of gap plants. Along a gradient from the gap center to a non-gap stand, seed density in the litter layer, the number of species, and the Shannon-Wiener diversity index were gradually reduced, but these indices increased in the soil. The seed density in the gap center was 2415 ± 639 seeds/m2, near the gap center was 2218 ± 421 seeds/m2 and at the gap border area 1815 ± 311 seeds/m2. This shows that plants in gaps have good latent regenera-tion potential. In both gaps and non-gap stands, the Jaccard similarity index of seed in litter layer was the lar-gest, second largest at 5-10 cm soil depth, and the least at the 0-5 cm soil layer the index. The Jaccard index between the soil seed bank and the present plant community was large in the litter layer, but decreased with soil depth both in gaps and non-gap stands. The results show that soil seed banks are the main source of gap regeneration in the karst forests of Maolan and contribute significantly to gap regeneration.

  20. Seed Bank Variation under Contrasting Site Quality Conditions in Mixed Oak Forests of Southeastern Ohio, USA

    Directory of Open Access Journals (Sweden)

    Christine J. Small

    2010-01-01

    Full Text Available Seed bank composition was sampled in 192–2.5 m2 quadrats, established in six regenerating clearcut (∼7 years and six second-growth (∼125 years mixed-oak forest stands in southeastern Ohio. Seed bank and aboveground composition diverged markedly (Sørensen's coefficient <10%, emphasizing the importance of fast-growing, early-successional germinants to early ecosystem recovery. Seed richness was significantly (P<.01 higher in clearcut stands, suggesting declining richness with stand age. Richness estimations 28%–60% higher than observed values demonstrated high seed bank heterogeneity, emphasizing the need for intensive sampling to assess temperate forest seed bank variation. Site quality (topographic aspect strongly influenced seed bank composition, with greater importance of early-successional trees, thicket-forming shrubs, and nonnative species on mesic sites. Thus, forest seed banks are likely to play an important, site-dependent role in shaping competitive environments for commercially important timber species after harvesting and soil disturbance and have the potential for marked influence on postharvest forest development.

  1. Soil Seed Bank and Plant Community Development in Passive Restoration of Degraded Sandy Grasslands

    Directory of Open Access Journals (Sweden)

    Renhui Miao

    2016-06-01

    Full Text Available To evaluate the efficacy of passive restoration on soil seed bank and vegetation recovery, we measured the species composition and density of the soil seed bank, as well as the species composition, density, coverage, and height of the extant vegetation in sites passively restored for 0, 4, 7, and 12 years (S0, S4, S7, and S12 in a degraded grassland in desert land. Compared with S0, three more species in the soil seed bank at depths of 0–30 cm and one more plant species in the community was detected in S12. Seed density within the topsoil (0–5 cm was five times higher in S12 than that in S0. Plant densities in S7 and S12 were triple and quadruple than that in S0. Plant coverage was increased by 1.5 times (S4, double (S7, and triple (S12 compared with S0. Sørensen’s index of similarity in species composition between the soil seed bank and the plant community were high (0.43–0.63, but it was lower in short-term restoration sites (S4 and S7 than that in no and long-term restoration sites (S0 and S12. The soil seed bank recovered more slowly than the plant community under passive restoration. Passive restoration is a useful method to recover the soil seed bank and vegetation in degraded grasslands.

  2. The accumulation of genetic diversity within a canopy-stored seed bank.

    Science.gov (United States)

    Ayre, David; O'Brien, Eleanor; Ottewell, Kym; Whelan, Rob

    2010-07-01

    Many plants regenerate after fire from a canopy-stored seed bank, in which seed are housed in fire resistant confructescences (cones) that remain on maternal plants. This strategy would be favoured if plants accumulate a sufficiently large and genetically diverse seed bank during interfire intervals. We use a 16-year demographic study and surveys of microsatellite variation to quantify and explain the rate of accumulation of genetic diversity within the canopy seed bank of the shrub Banksia spinulosa. Flowering and fruit set were highly variable. An initial sample in 1991 of 354 reproductively mature plants generated 426 cones over 16 years, of which only 55 cones from 40 maternal plants persisted until 2005. By genotyping seed from these 55 cones we demonstrated that genetic diversity accumulated rapidly within the seed bank. Resampling revealed that diversity was determined by the number, not the age, of cones. Cones were widely distributed among plants, outcrossing rates were high (mean t(m) = 1.00 +/- 0.04) and biparental inbreeding low. Adults displayed little evidence of isolation by distance and the genotypic diversity of seed cohorts was independent of the density of neighbouring potential sires. We therefore estimate that within at least 13 individual years the number of cones produced per year (14-63) would have contained 100% of the adult genetic diversity. We conclude that a highly outcrossed mating system and relatively widespread pollen dispersal ensure the rapid development of a genetically diverse and spatially and temporally homogeneous seed bank.

  3. The effect of seed morphology on the potential dispersal of aquatic macrophytes by the common carp (Cyprinus carpio)

    NARCIS (Netherlands)

    Pollux, B.J.A.; de Jong, M.D.E.; Steegh, A.; Ouborg, N.J.; Van Groenendael, J.M.; Klaassen, M.R.J.

    2006-01-01

    1. The potential for seed dispersal by fish (ichthyochory) will vary among aquatic plants because of differences in seed size and morphology. 2. To examine how seed morphology influences the probability of dispersal by the common carp (Cyprinus carpio), we studied seed ingestion, retention time and

  4. Characteristics and dynamics of the soil seed bank at the north edge of Taklimakan Desert

    Institute of Scientific and Technical Information of China (English)

    LI Ning; FENG Gu; TIAN ChangYan

    2007-01-01

    In order to understand the potential of revegetation of halophytic community at the north edge of Taklimakan Desert, the species structure, storage capacity, the vertical distribution pattern and seasonal dynamics of soil seed bank and their interrelationship with community structure of above-ground plants were investigated. The results show that (i) 9 species were identified from seed bank in different seasons indicating that plant composition in this area was simple. (ii) The seed density in soil was 222±10.79 grain/m2 on average, and showed a seasonal variation range from 132±8.16 grain/m2 in summer to 303±12.70 grain/m2 in autumn. (iii) The similarity coefficient between soil seed bank and above-ground vegetation was 0.778. (iv) Vertically, seed densities declined with soil depth. 82.4% of total seeds were found in the top 3 cm of soil profile. No active seeds were found in soil profile below 6 cm. It is concluded that the seed bank at the north edge of Taklimakan Desert contains active seeds of all plant species observed on above ground, and is able to supply potential contribution to reconstruction of vegetation.

  5. A comparison of seed banks across a sand dune successional gradient at Lake Michigan dunes (Indiana, USA)

    Science.gov (United States)

    Leicht-Young, S. A.; Pavlovic, N.B.; Grundel, R.; Frohnapple, K.J.

    2009-01-01

    In habitats where disturbance is frequent, seed banks are important for the regeneration of vegetation. Sand dune systems are dynamic habitats in which sand movement provides intermittent disturbance. As succession proceeds from bare sand to forest, the disturbance decreases. At Indiana Dunes National Lakeshore, we examined the seed banks of three habitat types across a successional gradient: foredunes, secondary dunes, and oak savanna. There were differences among the types of species that germinated from each of the habitats. The mean seed bank density increased across the successional gradient by habitat, from 376 to 433 to 968 seeds m-2, but with foredune and secondary dune seed bank densities being significantly lower than the savanna seed bank density. The number of seeds germinated was significantly correlated with soil organic carbon, demonstrating for this primary successional sequence that seed density increases with stage and age. The seed bank had much lower species richness than that of the aboveground vegetation across all habitats. Among sites within a habitat type, the similarity of species germinated from the seed banks was very low, illustrating the variability of the seed bank even in similar habitat types. These results suggest that restoration of these habitats cannot rely on seed banks alone. ?? 2008 Springer Science+Business Media B.V.

  6. Weed seed bank response to 12 years of different fertilization systems.

    Science.gov (United States)

    De Cauwer, B; Van den Berge, K; Cougnon, M; Bulcke, R; Reheul, D

    2010-01-01

    Fertilizer amendments can impact weed populations in a variety of ways. This study evaluated the effects of 12 year-long applications of different fertilization systems on size and composition of the weed seed bank in a conventionally managed maize monoculture field. Fertilization systems included all factorial combinations of two dairy cattle slurry rates, three vegetable, fruit and garden waste (VFG) compost rates, and three synthetic N fertilizer rates. Soil samples were taken in each subplot in May 2008 after sowing and prior to herbicide application. Residues recovered from soil samples were tested for weed seedling emergence to characterize soil seed banks. Total weed seed bank density was affected by mineral N fertilization but not by compost or animal slurry application. Weed seed bank composition was related to compost amendment and mineral N fertilization. Annual compost amendments reduced seed bank density of some persistent species (e.g., Chenopodium album and Solanum nigrum) irrespective of mineral N fertilization. Compost is a promising tool for incorporation into integrated weed control strategies aimed at reducing weed seed bank persistence.

  7. Repeated drought alters resistance of seed bank regeneration in baldcypress swamps of North America

    Science.gov (United States)

    Lei, Ting; Middleton, Beth A.

    2017-01-01

    Recurring drying and wetting events are likely to increase in frequency and intensity in predicted future droughts in the central USA and alter the regeneration potential of species. We explored the resistance of seed banks to successive droughts in 53 sites across the nine locations in baldcypress swamps in the southeastern USA. Along the Mississippi River Alluvial Valley and northern Gulf of Mexico, we investigated the capacity of seed banks to retain viable seeds after successive periods of drying and wetting in a greenhouse study. Mean differences in species richness and seed density were compared to examine the interactions of successive droughts, geographical location and water regime. The results showed that both species richness and total density of germinating seedlings decreased over repeated drought trials. These responses were more pronounced in geographical areas with higher annual mean temperature. In seed banks across the southeastern swamp region, most species were exhausted after Trial 2 or 3, except for semiaquatic species in Illinois and Tennessee, and aquatic species in Texas. Distinct geographical trends in seed bank resistance to drought demonstrate that climate-induced drying of baldcypress swamps could influence the regeneration of species differently across their ranges. Despite the health of adult individuals, lack of regeneration may push ecosystems into a relict status. Seed bank depletion by germination without replenishment may be a major conservation threat in a future with recurring droughts far less severe than megadrought. Nevertheless, the protection of moist refugia might aid conservation.

  8. Effect of pre-planting irrigation, maize planting pattern and nitrogen on weed seed bank population.

    Science.gov (United States)

    Hemmati, E; Vazan, S; Oveisi, M

    2011-01-01

    Pre-planting irrigation and planting patterns are important factors in weed management that effect on seed bank. Additionally, the nitrogen is the most important factor in plant growth that affects weed-crop competition and ultimately, seed rain into the soil. A field experiment was conducted to study the effect of nitrogen application rates, pre-planting irrigation and maize planting patterns on weed seed bank population. Experimental factors were nitrogen rates at 4 levels (200, 300, 400 and 500 kg per hectare) as main plot; and pre-planting irrigation at 2 levels (irrigation before planting plus weeding emerged seedlings and, irrigation after sowing), and maize planting patterns (one-row and two-row planting of maize with same density per square of row length) that were assigned in a factorial arrangement to the sub plots. Soil samples were taken at the beginning of the season (before planting of maize) and at the end of the season (after harvest) at depth of 0-5 cm in the fixed quadrates (60 cm x 60 cm). The weed seeds were extracted from the soil samples and were identified using standard methods. The majority of weed seed bank populations included 6 weed species: Portulaca oleracea, Chenopodium album, Amaranthus retroflexus, Sorghum halepense, Daturea stramonium, Xanthium strumarium. Results showed that population of weed seed bank increased significantly with increasing nitrogen rate. The increasing rate was different between one-row and two-row planting patterns. The parameters indicated that seed bank population was much higher in a one row planting pattern of maize. With two-row planting, seed bank was decreased by 34, 26, 20 and 5% at 200, 300, 400 and 500 kg N/ha, respectively. Pre-planting irrigation was also found an effective implement to reduce the weed seed bank. When pre-planting irrigation was applied, seed bank was decreased by 57, 43, 34 and 9% at 200, 300, 400 and 500 kg N/ha. Increasing nitrogen because of weed's better growth and higher seed

  9. Does Ferocactus wislizeni (Cactaceae) have a between-year seed bank?

    Science.gov (United States)

    Bowers, Janice E.

    2000-01-01

    Field and laboratory experiments at Tumamoc Hill, Tucson, Arizona, U.S.A., demonstrated that Ferocactus wislizeni, a common perennial cactus in the northern Sonoran Desert, has a between-year seed bank. In laboratory studies, F. wislizeni seeds lost dormancy during storage at room temperature and had a light requirement for germination. Field experiments suggested that as much as 2% of the annual seed crop might escape post-dispersal predation even when unprotected; where suitable safe sites exist, a higher percentage might escape. Germination of seed recovered monthly from above- and below-ground components of an artificial seed bank showed that seeds can survive at least 18 months in and on the soil. Seed banks enable F. wislizeni to take advantage of favorable rains and temperatures throughout the growing season, thus increasing the number of opportunities for germination. Moreover, seed banks enable F. wislizeni to respond hugely when the climate seems especially favorable, thus producing the large cohorts necessary to compensate for high seedling mortality. (C) 2000 Academic Press.

  10. Soil seed bank characteristics in relation to rangeland degradation in communal areas of the Eastern Cape, South Africa

    CSIR Research Space (South Africa)

    Lesoli, MS

    2010-07-01

    Full Text Available A soil seed bank is defined as seeds at or beneath the soil surface that are capable of germinating. Soil seed banks are important in ecosystems where grasses account for a large part of the vegetation. This has implications on the future vegetation...

  11. Riparian soil seed banks and the potential for passive restoration of giant reed infested areas in Webb County, Texas

    Science.gov (United States)

    Habitat restoration projects can use seed bank information as early warning systems of patterns or degrees of habitat degradation; as changes in above ground vegetation directly impact below ground seed distribution. In multiple strategy restoration efforts, seed bank quality can be used as a decidi...

  12. Seed banks in a degraded desert shrubland: Influence of soil surface condition and harvester ant activity on seed abundance

    Science.gov (United States)

    DeFalco, L.A.; Esque, T.C.; Kane, J.M.; Nicklas, M.B.

    2009-01-01

    We compared seed banks between two contrasting anthropogenic surface disturbances (compacted, trenched) and adjacent undisturbed controls to determine whether site condition influences viable seed densities of perennial and annual Mojave Desert species. Viable seeds of perennials were rare in undisturbed areas (3-4 seeds/m2) and declined to harvester ant explained annual seed densities better than any other surface characteristics that were examined. Surface disturbances can have a varied impact on the condition of the soil surface in arid lands. Nevertheless, the consistently positive relationship between ground cover of litter and viable seed density emphasizes the importance of litter as an indicator of site degradation and recovery potential in arid lands.

  13. Dynamics and species diversity of soil seed bank of weeds in resource-saving technologies

    OpenAIRE

    SELYUCK M.P.; TOROPOVA E.Y.; STETSOV G.Y.; ZAHAROV A.F.

    2016-01-01

    The soil seed bank of weeds in No-till technology southern forest-steppe Novosibirsk region dominated by Panicum miliaceum, Setaria glauca, Amaranthus retroflexus, Polygonum linicola. The highest soil infestation with weed seeds was marked after peas and wheat monoculture. The main factor determining the species diversity and abundance of weed seeds the weather conditions were, the impact of crop rotation was 2 times lower.

  14. Soil warming increases plant species richness but decreases germination from the alpine soil seed bank.

    Science.gov (United States)

    Hoyle, Gemma L; Venn, Susanna E; Steadman, Kathryn J; Good, Roger B; McAuliffe, Edward J; Williams, Emlyn R; Nicotra, Adrienne B

    2013-05-01

    Global warming is occurring more rapidly above the treeline than at lower elevations and alpine areas are predicted to experience above average warming in the future. Temperature is a primary factor in stimulating seed germination and regulating changes in seed dormancy status. Thus, plant regeneration from seed will be crucial to the persistence, migration and post disturbance recruitment of alpine plants in future climates. Here, we present the first assessment of the impact of soil warming on germination from the persistent alpine soil seed bank. Contrary to expectations, soil warming lead to reduced overall germination from the soil seed bank. However, germination response to soil temperature was species specific such that total species richness actually increased by nine with soil warming. We further explored the system by assessing the prevalence of seed dormancy and germination response to soil disturbance, the frequency of which is predicted to increase under climate change. Seeds of a significant proportion of species demonstrated physiological dormancy mechanisms and germination of several species appeared to be intrinsically linked to soil disturbance. In addition, we found no evidence of subalpine species and little evidence of exotic weed species in the soil, suggesting that the soil seed bank will not facilitate their invasion of the alpine zone. In conclusion, changes in recruitment via the alpine soil seed bank can be expected under climate change, as a result of altered dormancy alleviation and germination cues. Furthermore, the alpine soil seed bank, and the species richness therein, has the potential to help maintain local species diversity, support species range shift and moderate species dominance. Implications for alpine management and areas for further study are also discussed.

  15. Modeling Size-number Distributions of Seeds for Use in Soil Bank Studies

    Institute of Scientific and Technical Information of China (English)

    Hugo Casco; Alexandra Soveral Dias; Luís Silva Dias

    2008-01-01

    Knowledge of soil seed banks is essential to understand the dynamics of plant populations and communities and would greatly benefit from the integration of existing knowledge on ecological correlations of seed size and shape. The present study aims to establish a feasible and meaningful method to describe size-number distributions of seeds in multi-species situations. For that purpose, size-number distributions of seeds with known length, width and thickness were determined by sequential sieving. The most appropriate combination of sieves and seeds dimensions was established, and the adequacy of the power function and the Weibull model to describe size-number distributions of spherical, non.spherical, and all seeds was investigated. We found that the geometric mean of seed length, width and thickness was the most adequate size estimator, providing shape-independent measures of seeds volume directly related to sieves mesh side, and that both the power function and the Weibuli model provide high quality descriptions of size-number distributions of spherical,non-spherical, and all seeds. We also found that, in spite of its slightly lower accuracy, the power function is, at this stage, a more trustworthy model to characterize size-number distributions of seeds in soil banks because in some Weibull equations the estimates of the scale parameter were not acceptable.

  16. Longevity of Juniperus procera seed lots under different storage conditions: implications for ex situ conservation in seed banks

    Institute of Scientific and Technical Information of China (English)

    Negash Mamo; Diriba Nigusie; Mulualem Tigabu; Demel Teketay; Miftah Fekadu

    2011-01-01

    Juniperus procera Endl. Is economically important timberspecies, but its populations are extremely small and fragmented in itsnatural habitat, thus, calling for immediate ex situ conservation. Here weexamined the effects of seed sources and storage temperature on thelongevity of Juniperus procera seed lots through collection and preserva-tion of seeds in seed banks. Seeds were collected from nine sites acrossthe species natural distribution in Ethiopia and stored in four warehouses:modern cold room (5℃), mud house (15℃), concrete block house (17℃)or corrugated iron house (20℃) for 42 months. Every three months, arandom sample of stored seeds were drawn and tested for germination. Ahighly significant variation (p 0.80; p<0.01). Cold storage also resulted in enhancement ofgermination through its stratification effect that terminated the non-deepphysiological dormancy of juniper seeds. In conclusion, seed lots withgood initial germination can be effectively stored in cold room (5℃) upto four years. In the absence of modern cold stores, mud houses can beused as a good altemative to store seeds at local level.

  17. Seed bank estimation and regeneration studies of Calophyllum apetalum Willd., from Western Ghats of Karnataka

    Directory of Open Access Journals (Sweden)

    C. N. Prasanna Kumar

    2015-09-01

    Full Text Available Studies on the seed production, modes of dispersal and regeneration patterns of threatened tree species are crucial for the management of their genetic diversity. The seed bank estimation of Calophyllum apetalum was assessed from three different locations of Western Ghats of Karnataka, using two factorial completely randomized design. The results revealed the seeds are dispersed by hydrochory and mammalochory. The post seed dispersal, seed bank estimation studies yielded a high seed density near the base of tree trunks, but it was varied between the distances and locations. The results revealed seed densities are insignificant among the forest ranges and significant with the distances. The in-situ regeneration studies revealed an insignificant relationship between the mean regeneration among the forest ranges and the distances. Also, the ex-situ regeneration studies resulted an insignificant relationship among forest ranges and the distances from which the seeds were collected. The highest seed germination through ex-situ regeneration suggested it, as a best suitable method of conservation of this species.

  18. Depth distribution and composition of seed banks under different tree layers in a managed temperate forest ecosystem

    Science.gov (United States)

    Godefroid, Sandrine; Phartyal, Shyam S.; Koedam, Nico

    2006-05-01

    In the present work we examined the composition and distribution across three soil layers of the buried soil seed bank under three different overstory types ( Fagus sylvatica, Quercus robur, Pinus sylvestris) and in logging areas in a 4383-ha forest in central Belgium. The objectives were: (1) to investigate whether species composition and species richness of soil seed banks are affected by different forest stands; (2) to examine how abundant are habitat-specific forest species in seed banks under different planted tree layers. The study was carried out in stands which are replicated, managed in the same way (even-aged high forest), and growing on the same soil type with the same land-use history. In the investigated area, the seed bank did show significant differences under oak, beech, pine and in logging areas, respectively in terms of size, composition and depth occurrence. All species and layers taken together, the seed bank size ranked as follows: oakwood > beechwood > logging area > pinewood. The same pattern was found for forest species. Seed numbers of Betula pendula, Calluna vulgaris, Dryopteris dilatata and Rubus fruticosus were significantly higher under the beech canopy. Carex remota, Impatiens parviflora and Lotus sp. showed a significantly denser seed bank in logging areas, while Digitalis purpurea seeds were significantly more abundant in soils under the oak canopy. The fact that the seed bank of an originally homogeneous forest varies under different planted stands highlights that a long period of canopy conversion can affect the composition and depth of buried seeds.

  19. Long-term persistence of pioneer species in tropical forest soil seed banks

    Energy Technology Data Exchange (ETDEWEB)

    Dalling, J W; Brown, T A

    2008-10-05

    In tropical forests, pioneer species regenerate from seeds dispersed directly into canopy gaps, and from seeds that persisted in soil seed banks before gap formation. However, life-history models suggest that selection for long-term persistence of seeds in soil should be weak, as persistence incurs a fitness cost resulting from prolonged generation time. We use a carbon dating technique to provide the first direct measurements of seed persistence in undisturbed tropical forest seed banks. We show that seeds germinate successfully from surface soil microsites up to 38 years after dispersal. Decades-long persistence may be common in pioneers with relatively large mass, and appears to be unrelated to specific regeneration requirements. In Croton billbergianus, a sub-canopy tree that recruits in abundant small gaps, long-term persistence is associated with short-distance ballistic seed dispersal. In Trema micrantha, a canopy tree with widespread dispersal, persistence is associated with a requirement for large gaps that form infrequently in old-growth forest.

  20. Consumers limit the abundance and dynamics of a perennial shrub with a seed bank

    Science.gov (United States)

    Kauffman, M.J.; Maron, J.L.

    2006-01-01

    For nearly 30 years, ecologists have argued that predators of seeds and seedlings seldom have population-level effects on plants with persistent seed banks and density-dependent seedling survival. We parameterized stage-based population models that incorporated density dependence and seed dormancy with data from a 5.5-year experiment that quantified how granivorous mice and herbivorous voles influence bush lupine (Lupinus arboreus) demography. We asked how seed dormancy and density-dependent seedling survival mediate the impacts of these consumers in dune and grassland habitats. In dune habitat, mice reduced analytical ?? (the intrinsic rate of population growth) by 39%, the equilibrium number of above-ground plants by 90%, and the seed bank by 98%; voles had minimal effects. In adjacent grasslands, mice had minimal effects, but seedling herbivory by voles reduced analytical ?? by 15% and reduced both the equilibrium number of aboveground plants and dormant seeds by 63%. A bootstrap analysis demonstrated that these consumer effects were robust to parameter uncertainty. Our results demonstrate that the quantitative strengths of seed dormancy and density-dependent seedling survival-not their mere existence-critically mediate consumer effects. This study suggests that plant population dynamics and distribution may be more strongly influenced by consumers of seeds and seedlings than is currently recognized. ?? 2006 by The University of Chicago.

  1. Soil seed bank, factors controlling germination and establishment of a Mediterranean shrub: Pistacia lentiscus L.

    Science.gov (United States)

    García-Fayos, Patricio; Verdú, Miguel

    1998-08-01

    The recruitment strategy of Pistacia lentiscus, an evergreen sclerophyllous shrub inhabiting the Mediterranean region, was studied in order to identify the key factors controlling seedling establishment and survival. The capacity to develop a seed bank, the loss of seed viability with time, the presence of dormancy mechanisms, the conditions to promote seed germination and the seedling dynamics were investigated. The results show that P. lentiscus has a transient seed bank with rapid seed germination occurring within the year. Dormancy was not present as seeds germinated successfully without light or temperature pretreatments. Only pulp removal and a long and abundant rain event (≥ 7 days; ≥ 100 L·m -2) appeared to be necessary for germination. Seed viability decreased drastically after 1 year. More seedlings emerged under shrub canopy than in open sites, as expected by the seed dispersal pattern and canopy effects on plant establishment. The high mortality observed in the few weeks after establishment indicates that seedling survival is a bottleneck in the recruitment process of P. lentiscus in dense shrublands. Some seedlings survived in a latent mode for at least 4 years.

  2. Soil seed banks and growth rates of an invasive species, Piper aduncum, in the lowlands of Papua New Guinea

    NARCIS (Netherlands)

    Rogers, H.R.; Hartemink, A.E.

    2000-01-01

    Secondary fallow vegetation in parts of the Papua New Guinea lowlands is dominated by the shrub Piper aduncum L. that originates from South America. Here we report on its seed bank, growth rate and biomass accumulation. P. aduncum accounted for 69 % (408 m[minus sign]2) of the seed bank in the

  3. Composition and abundance of fishes in the interface between open water and macrophyte banks, and the dynamics of this interface during morning and evening twilight, in lake Catalão, Amazonas, Brazil

    Directory of Open Access Journals (Sweden)

    Igor David da Costa

    2011-06-01

    Full Text Available This work studied the composition and abundance of the fishes that move between macrophyte banks and open water during the morning twilight (CM and afternoon twilight (CV. The collections were made using gillnets, along banks of Paspalum repens, at Catalão lake, in Amazonas, Brazil. A total of 222 individuals and 37 species were collected. Of these, 130 individuals were collected during the CM and 92 during the CV; 80 individuals were leaving during the CM and 40 individuals were leaving during the CV. Auchenipterus nuchalis, Pellona castelnaeana, Triportheus angulatus and T. albus were the most common and concentrated species collected in the CM and Pimelodus blochii was the most common species collected in the CV.

  4. An improved method for seed-bank analysis : Seedling emergence after removing the soil by sieving

    NARCIS (Netherlands)

    ter Heerdt, G.N.J.; Bekker, R.M.; Bakker, J.P.; Verweij, G.L.

    1. The seedling emergence method for assessing the size of the seed bank is improved by washing soil samples on a fine sieve and spreading the thus concentrated samples in a 3-5 mm thick layer on sterilized potting compost. 2. The method largely increases the number of seedlings that emerge as

  5. An improved method for seed-bank analysis : Seedling emergence after removing the soil by sieving

    NARCIS (Netherlands)

    ter Heerdt, G.N.J.; Bekker, R.M.; Bakker, J.P.; Verweij, G.L.

    1996-01-01

    1. The seedling emergence method for assessing the size of the seed bank is improved by washing soil samples on a fine sieve and spreading the thus concentrated samples in a 3-5 mm thick layer on sterilized potting compost. 2. The method largely increases the number of seedlings that emerge as compa

  6. Changes in vegetation and soil seed bank of meadow after waterlogging caused by Castor fiber

    Directory of Open Access Journals (Sweden)

    Magdalena Franczak

    2015-07-01

    Full Text Available Soil waterlogging is among abiotic stresses that influence species composition and productivity in numerous plant communities. The aim of the study was to find answer to the question of how waterlogging caused by beavers’ activity induces quantitative and qualitative changes of vegetation and soil seed bank levels of variable-moist meadows. An immediate effect of the waterlogging at the level of vegetation was the decline in species richness and a decrease in the values of the biodiversity index. Water stress inhibited growth and development of plants already present and, primarily, impeded recruitment of new individuals of species characteristic of variable-moist meadows, e.g. Cirsium rivulare, Filipendula ulmaria and Lythrum salicaria, which were replaced by Carex acutiformis. Prolonged waterlogging did not induce equally substantial changes in the soil seed bank as in the vegetation. Both in the waterlogged and control patches, slightly decreased species richness and biodiversity index were recorded. After waterlogging withdrawal, the reserves of the soil seed bank were slightly higher than the initial values. The differences were not statistically significant. In the waterlogged patch, the qualitative floristic similarity between taxa identified in the soil seed bank and vegetation cover declined, which was evidenced by the value of Jaccard’s index decreasing from 0.46 to 0.36. A reverse relationship was found in control patch, where the value of the similarity index slightly increased from 0.41 to 0.48.

  7. Spatio-temporal variation in a seed bank of a semi-arid region in northeastern Brazil

    Science.gov (United States)

    da Silva, Kleber A.; dos Santos, Danielle M.; dos Santos, Josiene M. F. F.; de Albuquerque, Ulysses P.; Ferraz, Elba M. N.; Araújo, Elcida de L.

    2013-01-01

    This study aimed to evaluate variations in the seed bank within a 3-year temporal series in order to answer the following questions: 1) Does the seed bank's species richness and seed density differ among climatic seasons and between years? 2) Are there differences in the richness and density of seed banks between the litter and mineral soil? 3) Can the seed bank's species richness and seed density be explained by characteristics such as the previous year's precipitation and soil depth (litter or mineral soil)? The samples were collected from litter and mineral soil (0-5 cm), in 210 sub-plots, during the dry and rainy seasons of each year (August 2005 through February 2008). Overall, 79 species were recorded. On average, 1 168, 304 and 302 seeds.m-2 were recorded in the seed bank during years I, II and III, respectively. This study showed that the Caatinga's seed bank is rich in herbaceous species, yet species' density and richness are low in the litter. Furthermore, about 43% of the variation in species richness and density was explained by soil depth (litter and mineral soil) and previous years' rainfall.

  8. Self-Affinity, Self-Similarity and Disturbance of Soil Seed Banks by Tillage.

    Science.gov (United States)

    Dias, Luís S

    2013-07-05

    Soil seed banks were sampled in undisturbed soil and after soil had been disturbed by tillage (tine, harrow or plough). Seeds were sorted by size and shape, and counted. Size-number distributions were fitted by power law equations that allowed the identification of self-similarity and self-affinity. Self-affinity and thus non-random size-number distribution prevailed in undisturbed soil. Self-similarity and thus randomness of size-number distribution prevailed after tillage regardless of the intensity of disturbance imposed by cultivation. The values of fractal dimensions before and after tillage were low, suggesting that short-term, short-range factors govern size-number distribution of soil seed banks.

  9. The long-term persistence of phytoplankton resting stages in aquatic "seed banks"

    DEFF Research Database (Denmark)

    Ellegaard, Marianne; Ribeiro, Sofia

    2017-01-01

    to terrestrial seed beds of vascular plants, but are much less studied. It is therefore timely to review the phenomenon of long-term persistence of aquatic resting stages in sediment seed banks. Herein we compare function, morphology and physiology of phytoplankton resting stages to factors central......In the past decade, research on long-term persistence of phytoplankton resting stages has intensified. Simultaneously, insight into life-cycle variability in the diverse groups of phytoplankton has also increased. Aquatic 'seed banks' have tremendous significance and show many interesting parallels...... such as pigments, cyanophycin or unidentified granular materials. They are reported to play central roles in evolutionary resilience and survival of catastrophic events. Promising areas for future research include the role of hormones in mediating dormancy, elucidating the mechanisms behind metabolic shut...

  10. Seed banks in desert grasslands and implications for management with an application to education and outreach

    Science.gov (United States)

    Ortiz-Barney, Elena

    Large areas of desert grasslands in the southwestern United States have been converted to shrublands through mismanagement. Land managers are interested in the potential for restoring these areas to grasslands. One possible source of new individuals of desirable grasses is the soil seed bank. This study was designed to investigate the quantity and spatial distribution of seeds in the soil seed bank and to estimate the possible effects of fire on the seed bank. To investigate the seed bank, soil samples were collected from sites with different vegetative cover representing a range of grassland conditions. At each site samples were collected from 3 microsites (under grasses, under shrubs, and interspaces) and separated into 3 depths (litter, 0--2 cm and 2--5 cm). Samples were grown in a growth chamber and plants were identified after emergence and flowering. To investigate the effects of prescribed burns on the seed bank, soil and surface temperatures during burns were measured at each microsite. Also, the heat tolerance of seeds of 8 species of perennial grasses was assessed by quantifying germination rates across a temperature gradient. Eleven species of perennial grasses germinated from soil and litter samples. Only 5 were abundant: the exotics Eragrostis curvula and E. Lehmanniana, and the natives E. intermedia, Lycurus setosus and Sporobolus cryptandrus. Most seed, as well as highest species richness, occurred in the litter layer and under shrubs. Temperatures during prescribed burns were highest in these same microsites, reaching averages between 100° and 250° Celsius (C). None of the species tolerated temperatures above 100°C. The implication of these results is that most grass seed reserves are stored in microsites that are likely to experience temperatures above their heat tolerance. Land managers should take this into account as a possible risk associated with using prescribed burns as part of their restoration efforts. As an application of this work to

  11. Soil Seed Bank Responses to Postfire Herbicide and Native Seeding Treatments Designed to Control Bromus tectorum in a Pinyon–Juniper Woodland at Zion National Park, USA

    Science.gov (United States)

    Brooks, Matthew L.; Hondo Brisbin, graduate student; Andrea Thode, Associate Professor; Karen Weber, graduate student

    2013-01-01

    The continued threat of an invasive, annual brome (Bromus) species in the western United States has created the need for integrated approaches to postfire restoration. Additionally, the high germination rate, high seed production, and seed bank carryover of annual bromes points to the need to assay soil seed banks as part of monitoring programs. We sampled the soil seed bank to help assess the effectiveness of treatments utilizing the herbicide Plateau® (imazapic) and a perennial native seed mix to control annual Bromus species and enhance perennial native plant establishment following a wildfire in Zion National Park, Utah. This study is one of few that have monitored the effects of imazapic and native seeding on a soil seed bank community and the only one that we know of that has done so in a pinyon–juniper woodland. The study made use of untreated, replicated controls, which is not common for seed bank studies. One year posttreatment, Bromus was significantly reduced in plots sprayed with herbicide. By the second year posttreatment, the effects of imazapic were less evident and convergence with the controls was evident. Emergence of seeded species was low for the duration of the study. Dry conditions and possible interactions with imazapic probably contributed to the lack of emergence of seeded native species. The perennial grass sand dropseed outperformed the other species included in the seed mix. We also examined how the treatments affected the soil seed bank community as a whole. We found evidence that the herbicide was reducing several native annual forbs and one nonnative annual forb. However, overall effects on the community were not significant. The results of our study were similar to what others have found in that imazapic is effective in providing a short-term reduction in Bromus density, although it can impact emergence of nontarget species.

  12. Persistence of seed bank under thick volcanic deposits twenty years after eruptions of Mount Usu, Hokkaido Island, Japan.

    Science.gov (United States)

    Tsuyuzaki, S; Goto, M

    2001-10-01

    The topsoil that contained the seed bank became buried under thick tephra after the eruptions of Mount Usu during 1977 and 1978. To determine the seed bank potential of the topsoil 20 yr after the eruptions, i.e., in 1998, 408 100-cm(3) samples were excavated under 115-185 cm of volcanic deposits. The topsoil was collected at 10-cm intervals along the horizontal scale and was divided into a 0-5 cm deep upper layer and a 5-10 cm deep lower layer. The seed bank was estimated by both the germination (GM) and flotation (FM) methods. In total, 23 species with an average seed density of 1317 seeds/m(2) were identified by GM, and 30 species with a density of 2986 seeds/m(2) were extracted by FM. The dominant species was Rumex obtusifolius, and perennial herbs, such as Carex oxyandra, Viola grypoceras, and Poa pratensis, were common. For nine species this study provided the first records for field seed longevity >20 yr. The seed density in the upper layer was double that in the lower layer, and the horizontal distribution was heterogeneous even at 10-cm intervals. We concluded that the seed bank has retained the original structure of the seed bank under the tephra and will persist longer with soil water content between 20 and 40%, no light, and low temperature fluctuations (±0.17°C of standard deviation in a day).

  13. Can soil seed banks serve as genetic memory? A study of three species with contrasting life history strategies.

    Directory of Open Access Journals (Sweden)

    Bohumil Mandák

    Full Text Available We attempted to confirm that seed banks can be viewed as an important genetic reservoir by testing the hypothesis that standing (aboveground plants represent a nonrandom sample of the seed bank. We sampled multilocus allozyme genotypes from three species with different life history strategies: Amaranthus retroflexus, Carduus acanthoides, Pastinaca sativa. In four populations of each species we analysed the extent to which allele and genotype frequencies vary in consecutive life history stages including the summer seed bank, which has been overlooked up to now. We compared the winter seed bank (i.e., seeds collected before the spring germination peak, seedlings, rosettes, the summer seed bank (i.e., seeds collected after the spring germination peak and fruiting plants. We found that: (1 All three species partitioned most of their genetic diversity within life history stages and less among stages within populations and among populations. (2 All genetic diversity parameters, except for allele frequencies, were similar among all life history stages across all populations in different species. (3 There were differences in allele frequencies among life history stages at all localities in Amaranthus retroflexus and at three localities in both Carduus acanthoides and Pastinaca sativa. (4 Allele frequencies did not differ between the winter and summer seed bank in most Carduus acanthoides and Pastinaca sativa populations, but there was a marked difference in Amaranthus retroflexus. In conclusion, we have shown that the summer seed bank is not genetically depleted by spring germination and that a majority of genetic diversity remains in the soil through summer. We suggest that seed banks in the species investigated play an important role by maintaining genetic diversity sufficient for recovery rather than by accumulating new genetic diversity at each locality.

  14. Seed Bank Contribution to Vascular Plant Richness on Temporary Floating Islands

    Science.gov (United States)

    Cherry, J. A.

    2005-05-01

    Fluctuating water levels create opportunities for recruitment of new individuals from wetland seed banks. In this study, floating island formation functioned similarly to drawdowns in water level by creating patches of sediment that were less inundated than the surrounding, undisturbed deep-water marsh. To examine if and how seed banks contributed to temporary formation of distinct plant assemblages on these islands, field surveys of plant percent cover on and off of islands were conducted over two years, along with a controlled greenhouse experiment in which inundation was manipulated. Plant assemblages differed significantly on and off of floating islands. Floating-leaved perennials dominated undisturbed deep-water marsh, while emergent species dominated floating islands. Moreover, species richness was greater on islands than in the undisturbed deep-water marsh. Plant assemblages in the greenhouse experiment also differed among inundation treatments in a manner consistent with differences observed in field surveys. These results demonstrate that floating island formation temporarily altered levels of inundation favoring the germination of a more species-rich, emergent plant assemblage. Because these islands persisted long enough for several species to set seed, their formation may contribute to the maintenance of the seed bank and help maintain populations of otherwise rare species within the deep-water marsh.

  15. Pharmacognostical Studies of the Seed of Lagonychium farctum (Banks and Sol. Bobr. Growing in Egypt

    Directory of Open Access Journals (Sweden)

    Samia M. El-Sayyad

    2013-03-01

    Full Text Available Lagonychium farctum (Banks & Sol. Bobr.is a wild plant growing in the deserts of Upper Egypt as a prickly perennial shrub with monopodial branches. It belongs to family Leguminosae. The plant is usually branching from the base and attains up to 2.5 m in height. It is used in traditional system of medicine as an astringent as well as antidysenteric. The present study investigates various standardized parameters such as macroscopic and microscopic characters which could be helpful in authentication of the seed of Lagonychium farctum. (Banks & Sol. Bobr.

  16. Seasonal variation in soil seed bank size and species composition of selected habitat types in Maputaland, South Africa

    Directory of Open Access Journals (Sweden)

    M. J. S. Kellerman

    2007-12-01

    Full Text Available Seasonal variation in seed bank size and species composition of five selected habitat types within the Tembe Elephant Park. South Africa, was investigated. At three-month intervals, soil samples were randomly collected from five different habitat types: a, Licuati forest; b, Licuati thicket; c, a bare or sparsely vegetated zone surrounding the forest edge, referred to as the forest/grassland ecotone; d, grassland; and e, open woodland. Most species in the seed bank flora were either grasses, sedges, or forbs, with hardly any evidence of woody species. The Licuati forest and thicket soils produced the lowest seed densities in all seasons.  Licuati forest and grassland seed banks showed a two-fold seasonal variation in size, those of the Licuati thicket and woodland a three-fold variation in size, whereas the forest/grassland ecotone maintained a relatively large seed bank all year round. The woodland seed bank had the highest species richness, whereas the Licuati forest and thicket soils were poor in species. Generally, it was found that the greatest correspondence in species composition was between the Licuati forest and thicket, as well as the forest/grassland ecotone and grassland seed bank floras.

  17. Relationship between seed bank expression, adult longevity and aridity in species of Chaetanthera (Asteraceae) in central Chile.

    Science.gov (United States)

    Arroyo, M T K; Chacon, P; Cavieres, L A

    2006-09-01

    Broad surveys have detected inverse relationships between seed and adult longevity and between seed size and adult longevity. However, low and unpredictable precipitation is also associated with seed bank (SB) expression in semi-arid and arid areas. The relationship between adult longevity, SB formation, seed mass and aridity is examined in annual and perennial herbs of Chaetanthera (Asteraceae) from the Chilean Mediterranean-type climate and winter-rainfall desert areas over a precipitation range of one order of magnitude. Seeds of 18 species and subtaxa (32 populations) were buried in field locations, and exhumed after two successive germination periods. Seeds not germinating in the field were tested in a growth chamber, and remnant intact seed tested for viability. Seed banks were classed as transient or persistent. The effect of life form, species, population and burial time on persistent SB size was assessed with factorial ANOVA. Persistent seed bank size was compared with the Martonne aridity index (shown to be a surrogate for inter-annual variation in precipitation) and seed size using linear regression. ANCOVA assessed the effect of life-form on SB size with aridity as covariate. Three species had a transient SB and 15 a persistent SB. ANOVA revealed a significant effect of life-form on SB size with annuals having larger SB size and greater capacity to form a persistent SB than perennials. Significant inter-population variation in SB size was found in 64% of cases. Seed mass was negatively correlated with persistent SB size. Persistent seed bank size was significantly correlated with the Martonne aridity index in the perennial and annual species, with species from more arid areas having larger persistent SBs. However, when aridity was considered as a covariate, ANCOVA revealed no significant differences between the annual and perennial herbs. Persistent seed bank size in Chaetanthera appears to reflect environmental selection rather than any trade-off with

  18. Long-term, large scale banking of citrus species embryos: comparisons between cryopreservation and other seed banking temperatures.

    Science.gov (United States)

    Malik, S K; Chaudhury, R; Pritchard, H W

    2012-01-01

    The long-term, large scale application of embryo cryopreservation has been assessed rarely and comparisons of viability loss for partially dried material with conventional seed bank storage conditions infrequently made. Five citrus species were cryopreserved following air drying of embryos (seed minus the testa) and embryonic axes: rough lemon (Citrus jambhiri), pommelo (C. grandis), mandarin (C. reticulata), citron (C. medica) and kagzi lime (C. aurantifolia). Although drying rates to c. 10 percent moisture content (MC) were approximately 10-times faster for isolated axes compared to embryos, the optimum MCs for cryopreservation were generally similar within a species, varying from c. 10 percent (C. jambhiri) to c. 20 percent (C. medica). Nonetheless, the hydration window for cryopreservation of the axis was usually wider than for the embryo. For all species, embryo or axis survival after cryopreservation ranged from 65 to 96 percent (C. medica axes), producing normal healthy seedlings from embryos and plantlets from axes without intervening callus growth in vitro. Whilst partially dried embryos of all five species survived fully liquid nitrogen vapour storage for 120 days, viability loss was rapid at -20 degree C, 5 degree C and ambient temperature, with a maximum interpolated half-life across these temperatures of c. 80 days for C. grandis at 5 degree C. The developed cryopreservation protocols were applied routinely to cryobank 377 accessions of Citrus germplasm from field genebanks, farmer's orchards, semi-wild and wild sources. After an average of 6.3 to 8.4 years cryo-storage, between 69 and 81 percent of accessions per species retained > 70 percent of the viability after desiccation. The results provide irrevocable evidence for the importance of cryopreservation for the banking of seeds of higher plants.

  19. Impact of municipal wastewater effluent on seed bank response and soils excavated from a wetland impoundment

    Science.gov (United States)

    Finocchiaro, R.G.; Kremer, R.J.; Fredrickson, L.H.

    2009-01-01

    Intensive management of wetlands to improve wildlife habitat typically includes the manipulation of water depth, duration, and timing to promote desired vegetation communities. Increased societal, industrial, and agricultural demands for water may encourage the use of alternative sources such as wastewater effluents in managed wetlands. However, water quality is commonly overlooked as an influence on wetland soil seed banks and soils. In four separate greenhouse trials conducted over a 2-yr period, we examined the effects of municipal wastewater effluent (WWE) on vegetation of wetland seed banks and soils excavated from a wildlife management area in Missouri, USA. We used microcosms filled with one of two soil materials and irrigated with WWE, Missouri River water, or deionized water to simulate moist-soil conditions. Vegetation that germinated from the soil seed bank was allowed to grow in microcosms for approximately 100 d. Vegetative taxa richness, plant density, and biomass were significantly reduced in WWE-irrigated soil materials compared with other water sources. Salinity and sodicity rapidly increased in WWE-irrigated microcosms and probably was responsible for inhibiting germination or interfering with seedling development. Our results indicate that irrigation with WWE promoted saline-sodic soil conditions, which alters the vegetation community by inhibiting germination or seedling development. ?? 2009, The Society of Wetland Scientists.

  20. Timing of fire relative to seed development may enable non-serotinous species to recolonize from the aerial seed banks of fire-killed trees

    Directory of Open Access Journals (Sweden)

    S. T. Michaletz

    2013-07-01

    Full Text Available The existence of non-serotinous, non-sprouting species in fire regimes where serotiny confers an adaptive advantage is puzzling, particularly when these species recruit poorly from soil seed banks or from burn edges. In this paper, white spruce (Picea glauca (Moench Voss was used to show how the timing of fire relative to seed development may permit non-serotinous species to recolonize burned areas from the aerial seed banks of fire-killed trees. To estimate survival of seeds within closed cones during crown fires, cone heating was simulated using a one-dimensional conduction model implemented in a three-dimensional computational fluid dynamics fire behavior model. To quantify the area burned when germinable seed would be contained within closed cones during a mast year, empirical fire occurrence and seed development (germinability and cone opening data were compared for multiple locations across the white spruce range. Approximately 12% of cones contained viable seed following crown fire simulations (0.072 m s−1 mean spread rate; 9147 kW m−1 mean intensity, and roughly half of the historical area burned resulted from fires that occurred when closed cones would contain germinable seed. Together, these results suggest that non-serotinous species may recolonize burned areas from in situ aerial seed banks, and that this may be an important cause of their existence in fire regimes to which they otherwise seem poorly suited.

  1. Seed dormancy, seedling establishment and dynamics of the soil seed bank of Stipa bungeana (Poaceae on the Loess Plateau of northwestern China.

    Directory of Open Access Journals (Sweden)

    Xiao Wen Hu

    Full Text Available Studying seed dormancy and its consequent effect can provide important information for vegetation restoration and management. The present study investigated seed dormancy, seedling emergence and seed survival in the soil seed bank of Stipa bungeana, a grass species used in restoration of degraded land on the Loess Plateau in northwest China. Dormancy of fresh seeds was determined by incubation of seeds over a range of temperatures in both light and dark. Seed germination was evaluated after mechanical removal of palea and lemma (hulls, chemical scarification and dry storage. Fresh and one-year-stored seeds were sown in the field, and seedling emergence was monitored weekly for 8 weeks. Furthermore, seeds were buried at different soil depths, and then retrieved every 1 or 2 months to determine seed dormancy and seed viability in the laboratory. Fresh seeds (caryopses enclosed by palea and lemma had non-deep physiological dormancy. Removal of palea and lemma, chemical scarification, dry storage (afterripening, gibberellin (GA3 and potassium nitrate (KNO3 significantly improved germination. Dormancy was completely released by removal of the hulls, but seeds on which hulls were put back to their original position germinated to only 46%. Pretreatment of seeds with a 30% NaOH solution for 60 min increased germination from 25% to 82%. Speed of seedling emergence from fresh seeds was significantly lower than that of seeds stored for 1 year. However, final percentage of seedling emergence did not differ significantly for seeds sown at depths of 0 and 1 cm. Most fresh seeds of S. bungeana buried in the field in early July either had germinated or lost viability by September. All seeds buried at a depth of 5 cm had lost viability after 5 months, whereas 12% and 4% seeds of those sown on the soil surface were viable after 5 and 12 months, respectively.

  2. Seed dormancy, seedling establishment and dynamics of the soil seed bank of Stipa bungeana (Poaceae) on the Loess Plateau of northwestern China.

    Science.gov (United States)

    Hu, Xiao Wen; Wu, Yan Pei; Ding, Xing Yu; Zhang, Rui; Wang, Yan Rong; Baskin, Jerry M; Baskin, Carol C

    2014-01-01

    Studying seed dormancy and its consequent effect can provide important information for vegetation restoration and management. The present study investigated seed dormancy, seedling emergence and seed survival in the soil seed bank of Stipa bungeana, a grass species used in restoration of degraded land on the Loess Plateau in northwest China. Dormancy of fresh seeds was determined by incubation of seeds over a range of temperatures in both light and dark. Seed germination was evaluated after mechanical removal of palea and lemma (hulls), chemical scarification and dry storage. Fresh and one-year-stored seeds were sown in the field, and seedling emergence was monitored weekly for 8 weeks. Furthermore, seeds were buried at different soil depths, and then retrieved every 1 or 2 months to determine seed dormancy and seed viability in the laboratory. Fresh seeds (caryopses enclosed by palea and lemma) had non-deep physiological dormancy. Removal of palea and lemma, chemical scarification, dry storage (afterripening), gibberellin (GA3) and potassium nitrate (KNO3) significantly improved germination. Dormancy was completely released by removal of the hulls, but seeds on which hulls were put back to their original position germinated to only 46%. Pretreatment of seeds with a 30% NaOH solution for 60 min increased germination from 25% to 82%. Speed of seedling emergence from fresh seeds was significantly lower than that of seeds stored for 1 year. However, final percentage of seedling emergence did not differ significantly for seeds sown at depths of 0 and 1 cm. Most fresh seeds of S. bungeana buried in the field in early July either had germinated or lost viability by September. All seeds buried at a depth of 5 cm had lost viability after 5 months, whereas 12% and 4% seeds of those sown on the soil surface were viable after 5 and 12 months, respectively.

  3. Spatial relationships between seed bank and seedling populations of Hordeum spontaneum and Cardaria draba in saffron (Crocus sativus L. fields

    Directory of Open Access Journals (Sweden)

    hasan makariyan

    2009-06-01

    Full Text Available Geostatistical techniques were used to characterize the spatial relationship between Hordeum spontaneum and Cardaria draba seedling and seed bank over the course of one growing season (2004-2005 in three saffron fields, located in Southern Khorasan, Iran. The density and spatial distribution of weeds varied widely with fields. The emergence percentage was higher for Cardaria draba than for H. spontaneum in all fields. Semivariograms showed spatial autocorrelation in seed bank and seedling populations of H. spontaneum and C. draba in all fields. Cross-semivariograms showed moderate to strong (63.3 to 94.7% and strong spatial continuity (78.4 to 95.4 %. between seed bank and seedling population densities of H. spontaneum and C. draba, respectively. Grey-scale field maps of C. draba seed banks corresponded visually to maps of seedling populations and could have been used to target control efforts, but visual correspondence between H. spontaneum seed bank and seedling maps was poor. Seed bank and seedling mapping may be useful for site-specific management, but additional information is needed to understand variation in the relationships between these two populations over time and space.

  4. Saving the gene pool for the future: Seed banks as archives.

    Science.gov (United States)

    Peres, Sara

    2016-02-01

    Ensuring the salvage of future sources is a challenge for plant geneticists and breeders, as well as historians and archivists. Here, this suggestion is illustrated with an account of the emergence, in the mid-20th century, of seed banks. These repositories are intended to enable the conservation of the world's crop genetic diversity against the 'genetic erosion' of crops, an unintended consequence of the global uptake of new high-yielding Green Revolution agricultural varieties. Plant breeders and scientists advocated a strategy of freezing and long-term storage of seed which enabled the salvage of genetic diversity for future users without requiring the continual cultivation of old varieties: seed banking could preserve valuable genetic material and enable agricultural modernisation to proceed. This account of crop genetic conservation therefore shows how breeders and geneticists sought to create their own seed archives from whence the evolutionary history of crops could be made accessible in ways that are useful for the future. This analysis suggests that conservation practices are informed by ideas about the future use of material, indicating that there is value in exploring concurrently the archival and historiographical issues relating to the biomolecular big biosciences.

  5. Potencial for natural forest regeneration from seed bank in an upper Paraná river floodplain, Brazil

    Directory of Open Access Journals (Sweden)

    Campos João Batista

    2003-01-01

    Full Text Available The historical process of deforestation was analyzed to evaluate the regeneration potential of forests from soil seed bank of Porto Rico island (53° 15'W and 22° 45'S in the upper Paraná river floodplain. Remnant forest fragments were identified and measured and the structure of arboreous vegetation and the composition of the seed bank of the forests and grassland of the island were evaluated. Results showed a fast process of deforestation with critical levels of forest: the remaining twice fragments represented only 5.98% of the total surface of the island. Disturbance by cattle raised on the island continuously degraded the fragments (backward succession, while expansion of areas with pasture favored severe impoverishment of the seed banks flora. The latter factor, soil compaction, and characteristics of seeds of existing arboreous species in the bank suggested that the immediate reestablishment of vegetation was more conditioned to introduction processes of seeds (by rain and ''flood seed'' than by stock of seeds in the bank.

  6. Effects of mowing date on the opportunities of seed dispersal of ditch bank plant species under different management regimes

    NARCIS (Netherlands)

    Leng, X.; Musters, C.J.M.; Snoo, de G.R.

    2011-01-01

    Mowing and plant removal is a traditional practice in low-intensity farming and likely to lead to high plant species richness. Even today, scientific knowledge on the impact of mowing on seed availability is still very limited. We studied whether the seed availability of ditch bank plant species was

  7. Checklist of the Aquatic Macrophytes

    African Journals Online (AJOL)

    The emergent macrophytes formed 93.3% of the total macrophyte .... accounted for 2.2% while emergent species with. 93.30% of ... proliferation of floating aquatic macrophytes like ..... Geoelectric Evalution of the Groundwater Potential of Parts.

  8. Ultraweak Photon Emission from the Seed Coat in Response to Temperature and Humidity-A Potential Mechanism for Environmental Signal Transduction in the Soil Seed Bank.

    Science.gov (United States)

    Footitt, Steven; Palleschi, Simonetta; Fazio, Eugenio; Palomba, Raffaele; Finch-Savage, William E; Silvestroni, Leopoldo

    2016-09-01

    Seeds beneath the soil sense the changing environment to time germination and seedling emergence with the optimum time of year for survival. Environmental signals first impact with the seed at the seed coat. To investigate whether seed coats have a role in environmental sensing we investigated their ultraweak photon emission (UPE) under the variable temperature, relative humidity and oxygen conditions they could experience in the soil seed bank. Using a custom-built luminometer we measured UPE intensity and spectra (300-700 nm) from Phaseolus vulgaris seeds, seed coats and cotyledons. UPE was greatest from the internal surface of the seed coat. Seed coat UPE increased concomitantly with both increasing temperature and decreasing relative humidity. Emission was oxygen dependent and it was abolished by treatment with dinitrophenylhydrazine, demonstrating the key role of seed coat carbonyls in the phenomenon. We hypothesize that beneath the soil surface the attenuation of light (virtual darkness: low background noise) enables seeds to exploit UPE for transducing key environmental variables in the soil (temperature, humidity and oxygen) to inform them of seasonal and local temperature patterns. Overall, seed coats were found to have potential as effective transducers of key fluctuating environmental variables in the soil.

  9. [Soil seed bank and its correlations with aboveground vegetation and environmental factors in water level fluctuating zone of Danjiangkou Reservoir, Central China].

    Science.gov (United States)

    Liu, Rui-Xue; Zhan, Juan; Shi, Zhi-Hua; Chen, Long-qing

    2013-03-01

    Taking the water level fluctuating zone of the Danjiangkou Reservoir as a case, and by the method of hierarchical cluster analysis, the soil seed banks at 37 sampling plots within the areas of 140-145 m elevation were divided into 6 groups, and the species composition, density, and diversity of the soil seed banks among the groups were compared. The differences between the soil seed banks and the aboveground vegetations were analyzed by S0rensen similarity coefficient, and the correlations among the soil seed banks, aboveground vegetations, and environmental factors were explored by principal component analysis (PCA) and multivariable regression analysis. At the same altitudes of the water level fluctuating zone, the species composition of the soil seed banks had obvious heterogeneity, and the density and diversity indices of the soil seed banks among different groups were great. The similarity coefficient between the soil seed banks and aboveground vegetations was low, and the species number in the soil seed banks was obviously lesser than that in the aboveground vegetations. The density of the soil seed banks was highly positively correlated with the aboveground vegetations coverage and species number and the soil texture, but highly negatively correlated with the soil water-holding capacity and soil porosity.

  10. 濒危植物蒙古扁桃种子雨和土壤种子库特征%The Seed Rain and Soil Seed Bank of Endangered Amygdalus mongolica

    Institute of Scientific and Technical Information of China (English)

    红雨; 邹林林; 朱清芳

    2012-01-01

    This experiment was conducted to study densities and spatial distribution of seed rain and soil seed bank of endangered plant Amygdalus mongolica at different altitudes between 2008 and 2009 in Baotou, Inner Mongolia. Self-renewal abilities and effect of changes in the micro-habitats on A. mongolica populations were analyzed. The purpose is to provide reference information for protection and reconstruction of A. mongolica populations. The results showed that the seed rain density changed obviously, while the soil seed bank density did not change significantly in the inter-annual. Seed rain mainly distributed around the shrub crown within 2 m, and the horizontal distribution was relatively narrow. The soil seed bank mainly distributed in the litter layer of 1. 50 m circumference section around the parent tree, in which it was not conducive to seed germination. There existed more significant differences in the seed rain and soil seed bank at different altitude zone ( P < 0. 05 ) , which showed a decreasing trend with the elevation increased. The correlation analysis showed that, seed rain densities had a significant negative correlation ( P < 0. 05 ) and soil seed bank densities had even a more significant negative correlation ( P < 0. 01) with altitude gradient. Therefore, altitude would be the most important factor that determines the seed rain and soil seed banks.

  11. Landscape pattern of seed banks and anthropogenic impacts in forested wetlands of the northern Mississippi River Alluvial Valley

    Science.gov (United States)

    Middleton, B.; Wu, X.B.

    2008-01-01

    Agricultural development on floodplains contributes to hydrologic alteration and forest fragmentation, which may alter landscape-level processes. These changes may be related to shifts in the seed bank composition of floodplain wetlands. We examined the patterns of seed bank composition across a floodplain watershed by looking at the number of seeds germinating per m2 by species in 60 farmed and intact forested wetlands along the Cache River watershed in Illinois. The seed bank composition was compared above and below a water diversion (position), which artificially subdivides the watershed. Position of these wetlands represented the most variability of Axis I in a Nonmetric Multidimensional Scaling (NMS) analysis of site environmental variables and their relationship to seed bank composition (coefficient of determination for Axis 1: r2 = 0.376; Pearson correlation of position to Axis 1: r = 0.223). The 3 primary axes were also represented by other site environmental variables, including farming status (farmed or unfarmed), distance from the mouth of the river, latitude, and longitude. Spatial analysis based on Mantel correlograms showed that both water-dispersed and wind/water-dispersed seed assemblages had strong spatial structure in the upper Cache (above the water diversion), bur the spatial structure of water-dispersed seed assemblage was diminished in the lower Cache (below the water diversion), which lost floodpulsing. Bearing analysis also Suggested that water-dispersal process had a stronger influence on the overall spatial pattern of seed assemblage in the upper Cache, while wind/water-dispersal process had a stronger influence in the lower Cache. An analysis of the landscapes along the river showed that the mid-lower Cache (below the water diversion) had undergone greater land cover changes associated with agriculture than did the upper Cache watershed. Thus, the combination of forest fragmentation and hydrologic changes in the surrounding landscape may

  12. Seed bank and established vegetation in the last remnants of the Mexican Central Plateau wetlands: the Lerma marshes

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    Carmen Zepeda G.

    2014-08-01

    Full Text Available Banco de semillas y vegetación establecida en los últimos remanentes de los humedales de la Meseta Central Mexicana: las ciénagas de Lerma. Seed banks play a central role in vegetation dynamics of many wetlands. Therefore, knowledge of seed reservoirs in the soils of aquatic communities should provide useful tools for conservation and restoration efforts. This study was conducted in the Lerma marshes, one of the last remnants of the vast wetlands that were once in the Mexican Central Plateau. The main objective was to determine the composition and abundance of seed bank and its relationship with established vegetation of the three Lerma marshes. In each marsh, we systematically selected 18 to 40 sampling sites. In each site, the composition of vascular plant vegetation was evaluated in two 10m lines perpendicular to the shore. Every 0.5m, we determined the coverage of species by measuring the intercepted length for each plant or group of plants. At each sampling site where we had evaluated the established vegetation, we collected a sample of the top 10cm of sediment; the soil cores were divided into an upper layer (0-5cm and a lower layer (5-10cm. These samples were used to evaluate the seed bank by the seedling emergence method. All samples were placed in a greenhouse at 20-25ºC and remained flooded for 15 weeks. Fortynine species were recorded in the vegetation. Chiconahuapan had the richest and most diverse flora and the greatest number of perennial species. A life-forms analysis showed that perennial herbs, especially rooted-emergent hydrophytes, dominated in the three wetlands. Sixty-one species were identified in the total seed bank; Chimaliapan had the most diverse total seed bank, whereas the mean seedling density was higher in Chignahuapan. Only two species of the total seed bank of each marsh had a density greater than 10% of the total, and more than half were uncommon. The upper layer of sediment (0-5cm contained two times more

  13. Seed bank and established vegetation in the last remnants of the Mexican Central Plateau wetlands: the Lerma marshes.

    Science.gov (United States)

    Zepeda, Carmen; Lot, Antonio; Nemiga, Xanat Antonio; Manjarrez, Javier

    2014-06-01

    Seed banks play a central role in vegetation dynamics of many wetlands. Therefore, knowledge of seed reservoirs in the soils of aquatic communities should provide useful tools for conservation and restoration efforts. This study was conducted in the Lerma marshes, one of the last remnants of the vast wetlands that were once in the Mexican Central Plateau. The main objective was to determine the composition and abundance of seed bank and its relationship with established vegetation of the three Lerma marshes. In each marsh, we systematically selected 18 to 40 sampling sites. In each site, the composition of vascular plant vegetation was evaluated in two 10m lines perpendicular to the shore. Every 0.5m, we determined the coverage of species by measuring the intercepted length for each plant or group of plants. At each sampling site where we had evaluated the established vegetation, we collected a sample of the top 10cm of sediment; the soil cores were divided into an upper layer (0-5cm) and a lower layer (5-10cm). These samples were used to evaluate the seed bank by the seedling emergence method. All samples were placed in a greenhouse at 20-25 degrees C and remained flooded for 15 weeks. Forty-nine species were recorded in the vegetation. Chiconahuapan had the richest and most diverse flora and the greatest number of perennial species. A life-forms analysis showed that perennial herbs, especially rooted-emergent hydrophytes, dominated in the three wetlands. Sixty-one species were identified in the total seed bank; Chimaliapan had the most diverse total seed bank, whereas the mean seedling density was higher in Chignahuapan. Only two species of the total seed bank of each marsh had a density greater than 10% of the total, and more than half were uncommon. The upper layer of sediment (0-5cm) contained two times more seeds/m2 and species per sample than the lower layer (5-10cm), and there was a significant decrease of seed density with depth. The detrended

  14. Analysis of the seed bank and soil fertility as tools for recovery of disturbed areas

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    Juliana Rosa Silva

    2012-03-01

    Full Text Available The perpetuation of plant species in forests depends on the viability of the seed bank and soil fertility. The goal of this study was to verify the species present in the seed bank, and the soil conditions that are available for use during recovery, of a disturbed area in Parque Municipal do Mocambo de Patos de Minas, MG. The site was divided into three areas and each area was further divided into nine random parcels that were 10x30m (300m2. Within each parcel, soil samples were collected in three places and three depths. Half of the samples were kept in the light and the other half in the dark. A soil sample from each area was collected to determine soil fertility. Herbaceous pioneer species emerged the most and the soil depth between 0-10cm had the highest emergency index. The soil tested was deficient in potassium and phosphorus; however, the values for other nutrients were good. This work found that the area studied can regenerate naturally, but it would be possible to speed up that process by introducing native plant species and native dispersers into area.

  15. Diverse seed banks favour adaptation of microalgal populations to future climate conditions.

    Science.gov (United States)

    Kremp, Anke; Oja, Johanna; LeTortorec, Anniina H; Hakanen, Päivi; Tahvanainen, Pia; Tuimala, Jarno; Suikkanen, Sanna

    2016-02-01

    Selection of suitable genotypes from diverse seed banks may help phytoplankton populations to cope with environmental changes. This study examines whether the high genotypic diversity found in the Baltic cyst pool of the toxic dinoflagellate Alexandrium ostenfeldii is coupled to phenotypic variability that could aid short-term adaptation. Growth rates, cellular toxicities and bioluminescence of 34 genetically different clones isolated from cyst beds of four Baltic bloom sites were determined in batch culture experiments along temperature and salinity gradients covering present and future conditions in the Baltic Sea. For all parameters a significant effect of genotype on the response to temperature and salinity changes was identified. General or site-specific effects of the two factors remained minor. Clones thriving at future conditions were different from the best performing at present conditions, suggesting that genotypic shifts may be expected in the future. Increased proportions of highly potent saxitoxin were observed as a plastic response to temperature increase, indicating a potential for higher toxicity of future blooms. The observed standing variation in Baltic seed banks of A. ostenfeldii suggests that the population is likely to persist under environmental change.

  16. Seasonal dynamics of the plant community and soil seed bank along a successional gradient in a subalpine meadow on the Tibetan Plateau.

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    Miaojun Ma

    Full Text Available BACKGROUND: Knowledge about how change the importance of soil seed bank and relationship between seed mass and abundance during vegetation succession is crucial for understanding vegetation dynamics. Many studies have been conducted, but their ecological mechanisms of community assembly are not fully understood. METHODOLOGY: We examined the seasonal dynamics of the vegetation and soil seed bank as well as seed size distribution along a successional gradient. We also explored the potential role of the soil seed bank in plant community regeneration, the relationship between seed mass and species abundance, and the relative importance of deterministic and stochastic processes along a successional gradient. PRINCIPAL FINDINGS: Species richness of seed bank increased (shallow layer and the total and seed density decreased (each layer and the total significantly with succession. Species richness and seed density differed significantly between different seasons and among soil depths. Seed mass showed a significant negative relationship with relative abundance in the earliest successional stage, but the relationships were not significant in later stages. Seed mass showed no relationship with relative abundance in the whole successional series in seed bank. Results were similar for both July 2005 and April 2006. CONCLUSIONS: The seed mass and abundance relationship was determined by a complex interaction between small and larger seeded species and environmental factors. Both stochastic processes and deterministic processes were important determinants of the structure of the earliest stage. The importance of seed bank decreased with succession. The restoration of abandoned farmed and grazed meadows to the species-rich subalpine meadow in Tibetan Plateau can be successfully achieved from the soil seed bank. However, at least 20 years are required to fully restore an abandoned agricultural meadow to a natural mature subalpine meadow.

  17. Soil seed bank and the effect of needle litter layer on seedling emergence in a tropical pine plantation.

    Science.gov (United States)

    Bueno, Andrea; Baruch, Zdravko

    2011-09-01

    The soil seed bank is the basis for community establishment and permanence and plays a primary role in natural restoration of degraded or altered ecosystems. As part of a restoration project, this study aimed to quantify the soil seed bank and to evaluate the effect of the needle litter layer on seedling emergence. Soil samples from a pine plantation were collected at random in the field and set to germinate in a greenhouse. Half of them were covered by a 6cm layer of dead pine needles simulating field conditions. In the field, 20 x 20cm plots were established, half were left intact and half were cleaned from the litter needles. All four treatments had 15 replicates and seedling emergence was recorded during six months. Soil seed bank density was 1 222/m2 from 17 morphotypes. In the field, the number of morphotypes and seedlings was only 9% and 6% respectively, of those emerged in the greenhouse, possibly due to watering and lack of predation in the latter. In both cases, herbs and graminoids were the dominant emerging seedlings, making up to 70-90% of the total. The needle layer didn't prevent seeds from reaching the soil but strongly reduced (> 50%) seedling emergence, although high variability within treatments resulted in no statistically significant differences. These results show that the needle layer hinders germination and/or emergence of seedlings from the seed bank. Its removal may be a recommended technique to accelerate natural restoration in pine plantations.

  18. 土壤种子库研究综述%A Review of Reseach on Soil Seed Bank

    Institute of Scientific and Technical Information of China (English)

    韩彦军

    2011-01-01

    The sum of all active seeds on the surface and in the soil is called soil seed bank,which is one of important research fieldes in the vegetation ecology. In this paper,the reseach progresses of soil seed bank are reviewed in terms of types, size, reseach mehtod, and the relation between soil seed bank and ground vegetation. Besides,the key issues to be solved in future research on soil seed bank are also hightlighted.%指出了土壤种子库是存在于土壤中和土壤表面所有具有活力种子的总和,是植被生态学中的重要研究领域之一。总结土壤种子库的研究方法、种子库分类和大小、种子库与地面植被的关系的主要内容,并在此基础上探讨了土壤种子库未来研究方向和急需解决的问题。

  19. Psychotria hoffmansegiana (Willd ex Roem. & Schult. Mull. Arg. and Palicourea marcagravii st. Hil. (Rubiaceae: potential for forming soil seed banks in a brazilian Cerrado

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    CG. Araújo

    Full Text Available The germinability of artificially buried Psychotria hoffmansegiana and Palicourea marcagravii seeds in Cerrado soil was tested, with the aim of evaluating whether dispersed seeds may be able to form a soil seed bank. The assays were carried out at a Cerrado Reserve in São Paulo State, Brazil. Seed samples were placed in nylon bags and buried at two different depths and in two different sites. Samples were periodically exhumed and germination tests were performed with both exhumed and dry stored seeds. In general, soil storage favoured seed survival and germination when compared to dry stored seeds. The seed germination was little affected by soil depth and by burial environment. Seeds of both species remained viable for at least 13 months, considering the time lapse between the collection and the end of the germination tests. It was suggested that both species can potentially form a persistent soil seed bank in Cerrado.

  20. Assessment of regeneration potential in the clonal macrophyte Miscanthus sacchariflorus (Poaceae) after burial disturbance based on bud bank size and sprouting capacity.

    Science.gov (United States)

    Chen, Xinsheng; Cao, Chenshu; Deng, Zhengmiao; Xie, Yonghong; Li, Feng; Hou, Zhiyong; Li, Xu

    2015-01-01

    The demography of the bud bank and its sprouting capacity are important for understanding the population dynamics of clonal plants and their potential responses to disturbances. To this end, we investigated the size and composition of the bud bank of Miscanthus sacchariflorus (Maxim.) Hack. immediately after flooding (November), in winter (January), in spring (March), and before flooding (May) in the wetlands of Dongting Lake. We then examined the sprouting capacity of axillary buds after sediment burial at 0, 5, 10, 15, and 20 cm. Total bud density of M. sacchariflorus ranged from 2524 buds m(-2) in November to 4293 buds m(-2) in March. Rhizome segments with inactive axillary buds, which represented the majority of the bud population (88.7% in November, 93.3% in May), did not sprout during the 140 days of the experiment (n = 250). The sprouting ratio was the highest for active axillary buds buried at 0 cm (64%) and decreased when buried at 10-20 cm (34%-40%). Due to the large number of active axillary buds in the bud bank (211-277 buds m(-2) from November to the following March), M. sacchariflorus could completely replace its aboveground shoot population, except in May (142 buds m(-2)). Increasing burial depth delayed bud emergence and reduced the growth period of shoots; however, burial depth did not affect the resulting plant height and only reduced the accumulated biomass at 20 cm. Therefore, the belowground bud bank and its strong sprouting capacity are important factors in the maintenance of local populations and colonization of new habitats for M. sacchariflorus after burial disturbances. The present methodology, which combined measurements of bud bank demography and sprouting capacity, may reflect the regeneration potential of clonal plants after burial disturbances.

  1. Effects of prescribed fire on the buried seed bank in mixed-hardwood forests of the southern Appalachian Mountains

    Science.gov (United States)

    Tara L. Keyser; Tracy L. Roof; Jacquelyne L. Adams; Dean Simon; Gordon Warburton

    2012-01-01

    This study characterizes the seed bank prior to and immediately following dormant-season prescribed fire in mature, mixed-Quercus spp. (oak) forests in the southern Appalachian Mountains. Thirty samples from the litter/duff (LD) and the top 5 cm of the mineral soil (MS) were collected from five 5-ha burn units (6 plots per experimental unit) before...

  2. Applying the seedling-emergence method under waterlogged conditions to detect the seed bank of aquatic plants in submerged sediments

    NARCIS (Netherlands)

    Boedeltje, G; ter Heerdt, GNJ; Bakker, JP

    2002-01-01

    Seed bank studies focused on submerged aquatic plants are generally performed under submerged conditions, using the seedling-emergence method. However, if a study targets at both submerged species and helophytes, submerged conditions are generally not suitable. We tested the emergence of seedlings f

  3. Restoration of the Cirsio dissecti-Molinietum in The Netherlands : Can we rely on soil seed banks?

    NARCIS (Netherlands)

    Matus, G; Verhagen, R; Bekker, RM; Grootjans, AP; Bruelheide, H.

    2003-01-01

    Vegetation and soil seed banks of a threatened Atlantic fen meadow community were studied using recent phytosociological records and seedling emergence from soil samples. Similarly managed but differently degraded stands that suffered different levels of species impoverishment were compared. The act

  4. Endemic hydrothermal vent species identified in the open ocean seed bank.

    Science.gov (United States)

    Gonnella, Giorgio; Böhnke, Stefanie; Indenbirken, Daniela; Garbe-Schönberg, Dieter; Seifert, Richard; Mertens, Christian; Kurtz, Stefan; Perner, Mirjam

    2016-06-13

    Hydrothermal vent systems host microbial communities among which several microorganisms have been considered endemic to this type of habitat. It is still unclear how these organisms colonize geographically distant hydrothermal environments. Based on 16S rRNA gene sequences, we compare the bacterial communities of sixteen Atlantic hydrothermal vent samples with our own and publicly available global open ocean samples. Analysing sequences obtained from 63 million 16S rRNA genes, the genera we could identify in the open ocean waters contained 99.9% of the vent reads. This suggests that previously observed vent exclusiveness is, in most cases, probably an artefact of lower sequencing depth. These findings are a further step towards elucidating the role of the open ocean as a seed bank. They can explain the predicament of how species expected to be endemic to vent systems are able to colonize geographically distant hydrothermal habitats and contribute to our understanding of whether 'everything is really everywhere'.

  5. Impacts of Mastication: Soil Seed Bank Responses to a Forest Thinning Treatment in Three Colorado (USA Conifer Forest Types

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    Akasha M. Faist

    2015-08-01

    Full Text Available Mastication is a forest fuel thinning treatment that involves chipping or shredding small trees and shrubs and depositing the material across the forest floor. By decreasing forest density mastication has been shown to lessen crown fire hazard, yet other impacts have only recently started to be studied. Our study evaluates how mastication treatments alter the density and composition of soil seed banks in three Colorado conifer forest types. The three forest types were (1 lodgepole pine, (2 ponderosa pine and (3 pinyon pine-juniper. Results showed that masticated sites contained higher seed bank densities than untreated sites: a pattern primarily driven by treatment effects in ponderosa pine forests. The seed bank was dominated by forbs regardless of forest type or treatment. This pattern of forb dominance was not observed in the aboveground vegetation cover as it demonstrated more even proportions of the functional groups. Graminoids showed a higher seed density in treated sites than untreated and, similarly, the identified non-native species only occurred in the treated ponderosa pine sites suggesting a potential belowground invasion for this forest type. These results suggest that presence of masticated material might not be creating a physical barrier hindering the transfer of seeds as predicted.

  6. Soil seed-bank structure and seed-germination dynamics contribute to pulsed shrub encroachment in a grassland-shrubland Chihuahuan ecotone

    Science.gov (United States)

    Moreno de las Heras, Mariano; Turnbull, Laura; Wainwright, John

    2015-04-01

    Shrub encroachment is pervasive in many arid and semi-arid landscapes worldwide. Large areas of desert grasslands in southwestern USA have shifted to sparse shrublands dominated by woody species over the last 150 years, accompanied by accelerated soil erosion. A complex range of mechanisms has been suggested to explain the occurrence of this phenomenon, including land-use change, climate variations, and soil erosion feedbacks of vegetation change. An important step to understand patterns in species dominance at desert grassland-shrubland transitions is the understanding of limitations on plant establishment imposed by the shrub-encroachment process. We analyze the structure of soil seed banks and the environmental limitations for seed germination (i.e. soil-water availability and temperature) of dominant species (black grama and creosotebush) across a Chihuahuan grassland-shrubland ecotone (Sevilleta National Wildlife Refuge, New Mexico). Seed density in soils across the ecotone is generally low (200-400 seeds m-2), although is largely concentrated in vegetation clumps (reaching peaks up to 800-1200 seeds m-2 in grass and shrub patches). Species composition in the soil seed-bank is strongly affected by shrub encroachment, with seed densities of grass species (and particularly for black grama) sharply decreasing in shrub-dominated areas. Optimal temperature for seed germination of both black grama and creosotebush (20-25°C) suggests synchronization of plant establishment with the summer monsoonal period. Water-level limitations for seed germination are similar for the two species (about 8-10% soil moisture), although creosotebush seeds need a longer time under optimal water-availability conditions for germination (about 12 days) than black grama seeds (about 7 days). Analysis of temporal series of field-based and simulated soil-moisture levels suggests that creosotebush requires very strong monsoonal precipitation for plant establishment, and therefore shrub

  7. Seed germination, seedling traits, and seed bank of the tree Moringa peregrina (Moringaceae) in a hyper-arid environment.

    Science.gov (United States)

    Gomaa, Nasr H; Picó, F Xavier

    2011-06-01

    Water-limited hot environments are good examples of hyper-aridity. Trees are scarce in these environments but some manage to survive, such as the tree Moringa peregrina. Understanding how trees maintain viable populations in extremely arid environments may provide insight into the adaptive mechanisms by which trees cope with extremely arid weather conditions. This understanding is relevant to the current increasing aridity in several regions of the world. Seed germination experiments were conducted to assess variation in seed mass, seed germination, and seedling traits of Moringa peregrina plants and the correlations among these traits. A seed burial experiment was also designed to study the fate of M. peregrina seeds buried at two depths in the soil for two time periods. On average, seeds germinated in three days and seedling shoots grew 0.7 cm per day over three weeks. Larger seeds decreased germination time and increased seedling growth rates relative to smaller seeds. Seeds remained quiescent in the soil and germination was very high at both depths and burial times. The after-ripening time of Moringa peregrina seeds is short and seeds germinate quickly after imbibition. Plants of M. peregrina may increase in hyper-arid environments from seeds with larger mass, shorter germination times, and faster seedling growth rates. The results also illustrate the adjustment in allocation to seed biomass and correlations among seed and seedling traits that allows M. peregrina to be successful in coping with aridity in its environment.

  8. Different Effects of Shrubs and Trees on Seed Bank Richness and Diversity in the Understory Soil (Case Study: Kerman Province, Sharbabak

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    2014-03-01

    Full Text Available This study aimed to investigate the effect of canopy trees and shrubs: Pistacia atlantica, Amygdalus scoparia, Amygdalus eburnean on the species diversity and richness of soil seed bank. Ten individuals of each species were selected and one quadrate was established in and outside of crown canopy of each species. In each plot, soil samples were collected from 0-5 and 5-10 cm depths. GLM was applied to assess the effect of woody species, canopy cover, and depth of sampling on the characteristics of soil seed bank. The paired t-test was used to compare the diversity and richness of soil seed banks beneath and outside the canopy. The results showed that the highest species richness of soil seed bank was related to Pistacia atlantica, 0.24, which was significantly higher than the average species richness of soil seed banks in other species Amygdalus scoparia, Amygdalus eburnea with 0.10 and 0.14, respectively. Pistacia atlantica had the highest species diversity with 0.65 compared to the two other species Amygdalus scoparia and Amygdalus eburnean with 0.48, 0.53, respectively. Paired t-test results showed that canopy of woody species significantly increased soil seed bank diversity and richness beneath their canopy. Our results indicated that canopy of tree and shrub species in arid region affected positively on soil seed bank preservation.

  9. Long-term effects of conversation to organic farming on the weed seed bank (Investigations on the Ökohof Seeben, 1994-2011

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    Wittmann, Christian

    2014-02-01

    Full Text Available Long term adaptation of weed flora to extensive land use (organic farming was analysed. 350 acres were equally managed by Ökohof Seeben in central German dry region. At permanent observation points seed banks were investigated in 1994, 1996 and 1998 as well as in 2004 and 2011 after a two-year transition period. The determination of seed banks was carried out by using greenhouse emergence assay for 20 observation points, each with 4 subplots. Size, composition and structure of the observed seed banks showed distinct timedependent changes for each site. Seed bank density rose from 17,420 to 33,200 seeds qm-2 during the 18 year observation period. From 1994 to 2011 seeds of approximately 80 species were detected. As organic farming continued site-typical weed species (e.g. Consolida regalis increased in number. However, two-thirds of the total seed bank consisted of eight ubiquitous species. Their proportion changed to varying degrees. The resulting dominance relationships showed only minor changes over time. In 1994 and 2011 the evenness value was at 0.70 and 0.73, respectively. By use of mass community coefficients distinctly differences between the seed banks of the different plots were found. The variation between the observation points is substantially greater than the time-dependent changes. In the examined area – of which soils show consistently good yield capacity – the location differentiation of weed flora that existed before introduction of organic farming is maintained.

  10. Germination and soil seed bank traits of Podocarpus angustifolius (Podocarpaceae: an endemic tree species from Cuban rain forests

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    Pablo Ferrandis

    2011-09-01

    Full Text Available Podocarpus angustifolius is an endangered recalcitrant-seeded small tree, endemic to mountain rain forests in the central and Pinar del Río regions in Cuba. In this study, the germination patterns of P. angustifolius seeds were evaluated and the nature of the soil seed bank was determined. Using a weighted two-factor design, we analyzed the combined germination response to seed source (i.e. freshly matured seeds directly collected from trees versus seeds extracted from soil samples and pretreatment (i.e. seed water-immersion for 48h at room temperature. Germination was delayed for four weeks (≈30 days in all cases, regardless of both factors analyzed. Moreover, nine additional days were necessary to achieve high germination values (in the case of fresh, pretreated seeds. These results overall may indicate the existence of a non-deep simple morphophysiological dormancy in P. angustifolius seeds. The water-immersion significantly enhanced seed germination, probably as a result of the hydration of recalcitrant seeds. Although germination of seeds extracted from soil samples was low, probably due to aging and pathogen effects throughout the time of burial, the study revealed the existence of a persistent soil seed bank (at least short-termed of ≈42 viable seeds per m² in the upper 10cm of soil. Such a record is noteworthy since references to persistent soil seed banks in recalcitrant-seeded species are scarce in the literature. The population consequences derived from the formation of persistent soil seed banks in this endangered species are discussed. Rev. Biol. Trop. 59 (3: 1061-1069. Epub 2011 September 01.Podocarpus angustifolius es un árbol endémico de los bosques lluviosos de la región de Pinar del Río y la parte central de Cuba, que se encuentra en peligro de extinción. En este estudio se evaluó la germinación de sus semillas y la naturaleza del banco de semillas del suelo. Específicamente, se analizó la respuesta germinativa

  11. The Longevity of Crop Seeds Stored Under Long-term Condition in the National Gene Bank of Bulgaria

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    Desheva Gergana

    2016-10-01

    Full Text Available Seed accessions from 7 plant families and 28 species stored for above 20 years in the National gene bank of Bulgaria were evaluated. All seed accessions were maintained as base collection under long-term storage conditions with low moisture contents (5±2% in hermetically closed containers at −18°C. On the basis of experimental data, the seed storage characters σ (standard deviation of seed death in storage, P50% (the time for viability to fall to 50% and P10% (the time for viability reduction of 10% were determined allowing the prediction of seed storage life and the regeneration needs. The results showed significant differences in loss of seed viability among species and within the species. After 20–24 years of storage, eleven crops showed minimal viability decline under 5% as compared to the initial viability (oats, barley, maize, bread wheat, durum wheat, smooth brome grass, faba bean, chickpea, sunflower, cucumber and pepper. For the same storage time, another group of crops (sorghum, triticale, orchard grass, tall fescue, common vetch, grass pea, lentil, common bean, rapeseed, tobacco, flax, cabbage and tomatoes presented 5–10% reduction of seed viability. More significant changes in seed viability – above 10% – were detected for peanuts, lettuce, soybean and rye. The σ values varied from 20.41 years (Arachis hypogaea L. to 500 years (for Avena sativa L. and Triticum aestivum L. There was wide variation across species, both in time taken for the viability to fall to 50% and in time taken for the seed viability reduction of 10%. The study illustrates the positive effect of both seed storability early monitoring and prediction of regeneration needs as a tool for limiting undesired losses.

  12. Variation on the amount of winter cover crops residues on weeds incidence and soil seed bank during an agricultural year

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    Márcia Maria Mauli

    2011-08-01

    Full Text Available This study analyzed possible interferences associated to the amount of crop residues produced by the black oats and the consortium of black oats, common vetch and forage turnip on weeds incidence and soil seed bank. It was a field trial with seven treatments and five replications. The cover crop was sown at throwing, cut at 100 days and residues were put on each respective plot, using a proportion of normal amount of produced straw, either its half and double. The heaviest weights were obtained from cover crop consortium and their application decreased weeds incidence in such area. The seeds bank and other analyzed parameters did not show statistical differences. According to these results, it was concluded that winter cover crop could be used in crops rotation with soybean.

  13. Modeling and analysis of a density-dependent stochastic integral projection model for a disturbance specialist plant and its seed bank.

    Science.gov (United States)

    Eager, Eric Alan; Rebarber, Richard; Tenhumberg, Brigitte

    2014-07-01

    In many plant species dormant seeds can persist in the soil for one to several years. The formation of these seed banks is especially important for disturbance specialist plants, as seeds of these species germinate only in disturbed soil. Seed movement caused by disturbances affects the survival and germination probability of seeds in the seed bank, which subsequently affect population dynamics. In this paper, we develop a stochastic integral projection model for a general disturbance specialist plant-seed bank population that takes into account both the frequency and intensity of random disturbances, as well as vertical seed movement and density-dependent seedling establishment. We show that the probability measures associated with the plant-seed bank population converge weakly to a unique measure, independent of initial population. We also show that the population either persists with probability one or goes extinct with probability one, and provides a sharp criteria for this dichotomy. We apply our results to an example motivated by wild sunflower (Helianthus annuus) populations, and explore how the presence or absence of a "storage effect" impacts how a population responds to different disturbance scenarios.

  14. Soil Seed Bank Dynamics in Tithonia diversifolia Dominated Fallowland Vegetation in Ile-Ife Area of Southwestern Nigeria

    Directory of Open Access Journals (Sweden)

    Samson Olajide OKE

    2009-12-01

    Full Text Available The soil seedbank of Tithonia diversifolia, an invasive species which dominates open waste fallowland vegetation was studied. Two different roadside sites which vary in extent of open waste land were selected.The species composition of the established vegetation was assessed in the two diferent sites. Twenty top soil samples were collected at five different distances (15 cm, 30 cm, 45 cm, 60 cm, and 75 cm inwards away from each main road in dry and rainy seasons and the seed bank composition was determined by greenhouse germination over a 6 month period. The similarity between the composition of the seed bank flora and that of the established vegetation was low. The least and the highest emerged seedlings density was recorded in the 15 metres and 75 metres respectively inwards away from the main road in both seasons. The results of the seedlings emergence is a reflection of the extent of open waste land dominated by the invasive species due to human disturbance (road construction on both sites. Overall results suggest that the emergence of the species from the soil seed bank may be due to the impact of the invasive species Tithonia diversifolia on other plant species in the study environment.

  15. Effects of simulated acid rain on germination, seedling growth and oxidative metabolism of recalcitrant-seeded Trichilia dregeana grown in its natural seed bank.

    Science.gov (United States)

    Ramlall, Chandika; Varghese, Boby; Ramdhani, Syd; Pammenter, Norman W; Bhatt, Arvind; Berjak, Patricia; Sershen

    2015-01-01

    Increased air pollution in a number of developing African countries, together with the reports of vegetation damage typically associated with acid precipitation in commercial forests in South Africa, has raised concerns over the potential impacts of acid rain on natural vegetation in these countries. Recalcitrant (i.e. desiccation sensitive) seeds of many indigenous African species, e.g. must germinate shortly after shedding and hence, may not be able to avoid exposure to acid rain in polluted areas. This study investigated the effects of simulated acid rain (rainwater with pH adjusted to pH 3.0 and 4.5 with 70:30, H2 SO4 :HNO3 ) on germination, seedling growth and oxidative metabolism in a recalcitrant-seeded African tree species Trichilia dregeana Sond., growing in its natural seed bank. The results suggest that acid rain did not compromise T. dregeana seed germination and seedling establishment significantly, relative to the control (non-acidified rainwater). However, pH 3.0 treated seedlings exhibited signs of stress typically associated with acid rain: leaf tip necrosis, abnormal bilobed leaf tips, leaf necrotic spots and chlorosis, reduced leaf chlorophyll concentration, increased stomatal density and indications of oxidative stress. This may explain why total and root biomass of pH 3.0 treated seedlings were significantly lower than the control. Acid rain also induced changes in the species composition and relative abundance of the different life forms emerging from T. dregeana's natural seed bank and in this way could indirectly impact on T. dregeana seedling establishment success.

  16. Influence of long-term different fertilization on soil weed seed bank diversity of a paddy soil under rice/rape rotation

    Institute of Scientific and Technical Information of China (English)

    Wei FENG; Genxing PAN; Sheng QIANG; Ruhai LI; Jiguang WEI

    2008-01-01

    A long-term fertilized paddy field under rice/ rape rotation in the Taihu Lake Region was selected to investigate the dynamics of soil weed seed diversity.Four fertilizer treatments were performed,including non-fert-ilizer (NF),chemical fertilizer only (CF),chemical fert-ilizer combined with pig manure (CMF) and chemical fertilizer plus crop stalk (CSF).We recorded the seed numbers and crop yields,estimated the weed seed bank density and identified the kinds of weed seeds in the top-soil (0-15 cm) in the study area using a stereomicroscope.Based on the records,we analyzed the effect of long-term fertilization on soil weed seed bank diversity and the rela-tionship between weed seed diversity and crop yields.Comparing the four treatments,it was found that in the cultivating seasons of both rice and rape,the density of soil weed seed bank was the lowest with the treatment of chemical fertilizer plus crop stalk.Whereas,the total num-ber of species and the weed seed bank diversity was the highest.Furthermore,the crop yields were at maximum and kept constant with this treatment.There was a def-inite correlation between fertilizer treatment and soil weed seed bank diversity and crop yields.It was concluded that balancing the fertilizer management was helpful in main-taining soil weed seed bank diversity,increasing crop yields and alleviating crop yield fluctuation.Therefore,among the four fertilizer treatments,chemical fertilizer plus rice crop stalk treatment was the best one to stimulate the productivity of agricultural ecosystems and simulta-neously protect biodiversity.

  17. banks

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2017-01-01

    The thaw period was a kind of bank from which our country set sail towards unexplored horizons. The series on the Moscow Palace of Young Pioneers is continued by the article by Felix Novikov (144-151, who writes about the history of the design of this wonderful building, today’s monument of architecture of Soviet modernism.

  18. Large sample area and size are needed for forest soil seed bank studies to ensure low discrepancy with standing vegetation.

    Directory of Open Access Journals (Sweden)

    You-xin Shen

    Full Text Available A large number of small-sized samples invariably shows that woody species are absent from forest soil seed banks, leading to a large discrepancy with the seedling bank on the forest floor. We ask: 1 Does this conventional sampling strategy limit the detection of seeds of woody species? 2 Are large sample areas and sample sizes needed for higher recovery of seeds of woody species? We collected 100 samples that were 10 cm (length × 10 cm (width × 10 cm (depth, referred to as larger number of small-sized samples (LNSS in a 1 ha forest plot, and placed them to germinate in a greenhouse, and collected 30 samples that were 1 m × 1 m × 10 cm, referred to as small number of large-sized samples (SNLS and placed them (10 each in a nearby secondary forest, shrub land and grass land. Only 15.7% of woody plant species of the forest stand were detected by the 100 LNSS, contrasting with 22.9%, 37.3% and 20.5% woody plant species being detected by SNLS in the secondary forest, shrub land and grassland, respectively. The increased number of species vs. sampled areas confirmed power-law relationships for forest stand, the LNSS and SNLS at all three recipient sites. Our results, although based on one forest, indicate that conventional LNSS did not yield a high percentage of detection for woody species, but SNLS strategy yielded a higher percentage of detection for woody species in the seed bank if samples were exposed to a better field germination environment. A 4 m2 minimum sample area derived from power equations is larger than the sampled area in most studies in the literature. Increased sample size also is needed to obtain an increased sample area if the number of samples is to remain relatively low.

  19. Effects of flooding on the spatial distribution of soil seed and spore banks of native grasslands of the Pantanal wetland

    Directory of Open Access Journals (Sweden)

    Patricia Carla de Oliveira

    2015-09-01

    Full Text Available ABSTRACTTo better understand the role that flooding plays in shaping plant communities of native floodable grasslands of the Pantanal and to characterize the spatial distribution of plants, we present the results of a survey of soil seed and spore banks using the seedling emergence method. We hypothesized that terrain subjected to the deepest and longest flooding should have higher propagule abundance and richness. The species composition and distribution of seeds and spores in the soil were assessed at five sites using three sampling positions at each according to inundation intensity. In each sample position 2cm-thick soil samples were collected in quadrats to a depth of 10cm. Litter was also collected as an independent layer. Sample monitoring in the greenhouse resulted in the emergence of 5489 seedlings, or 6353 propagules.m-2. Both the litter layer and the deepest soil layer had low abundances. A total of forty-four morphospecies (16 families were recorded. Both seedling abundance and species richness were concentrated in the more floodable center sections. Isoetes pedersenii, Eleocharis minima, Sagittaria guayanensis, Rotala mexicana, Eleocharis plicarhachis, and Panicum laxum were the most abundant species. The species composition and spatial distribution of the propagule bank suggests that flooding plays a crucial role in seasonal vegetation dynamics in Pantanal wetlands, mediated by the ability of the soil to host seeds and spores during dry season.

  20. Soil seed banks and their germination responses to cadmium and salinity stresses in coastal wetlands affected by reclamation and urbanization based on indoor and outdoor experiments

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Junhong, E-mail: junhongbai@163.com; Huang, Laibin, E-mail: seahuanglaibin@gmail.com; Gao, Zhaoqin; Lu, Qiongqiong; Wang, Junjing; Zhao, Qingqing

    2014-09-15

    Highlights: • A higher germination rate of soil seed bank was observed in the indoor experiment. • The outdoor experiment showed larger number and destiny of germinated seedlings. • Urbanization had greater impacts on soil seed banks than wetland reclamation. • Soil seed banks for wetland restoration were more suitable in the reclaimed region. • Suitable salt or Cd levels could activate seedling emergence in the soil seed bank. - Abstract: Indoor and outdoor seedling emergence experiments were conducted to thoroughly investigate germination patterns as affected by reclamation and urbanization, the ecological characteristics of soil seed banks, and their relationships with environmental factors in both urbanized and reclaimed regions of the Pearl River Delta in coastal wetlands. The germination rate of the soil seed bank was higher in the indoor experiment compared with that in the outdoor experiment, whereas the number and destiny of the germinated seedlings were greater in the outdoor experiment. The species diversity and number, as well as the richness and evenness indices, were higher in the urbanized region compared with the reclaimed region. However, the dominance and Sørensen similarity indices were greater in the reclaimed region compared with those indices in the urbanized region. Higher salinity and Cadmium (Cd) levels could inhibit seed germination; however, their suitable ranges (i.e. [0–2000 mg kg{sup −1}] for salinity and [0–4.0 mg kg{sup −1}] for available Cd) can activate seedling emergence, and more seedlings germinated under the intersectional levels at 0.34 mg kg{sup −1} available Cd and 778.6 mg kg{sup −1} salinity. Seawater intrusion caused by the sea level rise will possibly result in the salt-tolerant community in this area due to increasing salinity.

  1. Monitoring viability of seeds in gene banks: developing software tools to increase efficiency

    Science.gov (United States)

    Monitoring the decline of seed viability is essential for effective long term seed storage in ex situ collections. Recent FAO Genebank Standards recommend monitoring intervals at one-third the time predicted for viability to fall to 85% of initial viability. This poster outlines the development of ...

  2. Seed bank composition in a secondary forest in the Lower Delta of the Paraná River (Argentina

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    Fábio Kalesnik

    2013-03-01

    Full Text Available The native forests once occupying the coastal levees of the Lower Delta islands of the Paraná River (in Argentina have been replaced by commercial forests. Many of those forests have been abandoned, resulting in secondary forest formation that is subject to numerous invasive exotic species. A priori observations suggest that successional trends do not lead to recovery of the original forest. The aim of the present study was to analyze the role of invasive exotic species in these environments and the likelihood of recovery of the original forest cover. Therefore, we examined the composition of the seed bank and of the standing vegetation, as well as the population structure of tree species. Secondary forests are described as being in an intermediate successional stage, with few exotic species (mainly trees but with a high abundance of standing vegetation and seed banks. These exotic species will likely continue to successfully predominate in different forest strata over the next stages. Because of the low density of native tree species, it is difficult to predict their future persistence. In conclusion, ecological restoration strategies will be needed in order to increase native tree species richness and biodiversity of the forests in the Lower Delta of the Paraná River.

  3. Seed bank survival of an invasive species, but not of two native species, declines with invasion.

    Science.gov (United States)

    Orrock, John L; Christopher, Cory C; Dutra, Humberto P

    2012-04-01

    Soil-borne seed pathogens may play an important role in either hindering or facilitating the spread of invasive exotic plants. We examined whether the invasive shrub Lonicera maackii (Caprifoliaceae) affected fungi-mediated mortality of conspecific and native shrub seeds in a deciduous forest in eastern Missouri. Using a combination of L. maackii removal and fungicide treatments, we found no effect of L. maackii invasion on seed viability of the native Symphoricarpos orbiculatus (Caprifoliaceae) or Cornus drummondii (Cornaceae). In contrast, fungi were significant agents of L. maackii seed mortality in invaded habitats. Losses of L. maackii to soil fungi were also significant in invaded habitats where L. maackii had been removed, although the magnitude of the effect of fungi was lower, suggesting that changes in soil chemistry or microhabitat caused by L. maackii were responsible for affecting fungal seed pathogens. Our work suggests that apparent competition via soil pathogens is not an important factor contributing to impacts of L. maackii on native shrubs. Rather, we found that fungal seed pathogens have density-dependent effects on L. maackii seed survival. Therefore, while fungal pathogens may provide little biotic resistance to early invasion by L. maackii, our study illustrates that more work is needed to understand how changes in fungal pathogens during the course of an invasion contribute to the potential for restoration of invaded systems. More generally, our study suggests that increased rates of fungal pathogen attack may be realized by invasive plants, such as L. maackii, that change the chemical or physical environment of the habitats they invade.

  4. Fluoride remediation using floating macrophytes

    Directory of Open Access Journals (Sweden)

    Naba Kumar Mondal

    2014-04-01

    Full Text Available Six aquatic macrophytes, such as Pistia stratiotes, Ceratophyllum demersum, Nymphoides indica, Lemna major, Azolla pinnata,and Eichhornia crassipes were considered for remove fluoride from aqueous solution. Five different concentrations (10, 30, 50, and 100 ppm of fluoride solution were taken in 1 L plastic container. Fixed weight (20 g of macrophytes along with 500 ml fluoride solution was taken in each plastic container for 72 hours observation. Results demonstrated all the macrophytes show highest fluoride removal during 24 h to 48 h, but after 72 h their efficiency reduced drastically. The species N. indica showed better removal efficiency than other experimental macrophytes. In general, pigment measurement data indicated higher concentration at 72 h. However, Pistia sp. showed higher concentration of pigmentation at intermediate time interval (48 h. Higher level of dry weight to fresh weight ratio was recorded for L. major and A. pinnata at all concentrations, excepting at 10 ppm. In addition, all macrophytes showed lower RGR at higher concentration. Isotherm study indicated that macrophyte C. demersum is a good fitted with Freundlich and Langmuir isotherm whereas L. major with Langmuir isotherm during 24 hours.

  5. Seed bank dynamics of blowout penstemon in relation to local patterns of sand movement on the Ferris Dunes, south-central Wyoming

    Science.gov (United States)

    Kassie L. Tilini; Susan E. Meyer; Phil S. Allen

    2017-01-01

    Plants restricted to active sand dunes possess traits that enable both survival in a harsh environment and local migration in response to a shifting habitat mosaic. We examined seed bank dynamics of Penstemon haydenii S. Watson (blowout penstemon) in relation to local sand movement. We measured within-year sand movement along a 400 m transect and examined plant density...

  6. Dynamics of Weeds in the Soil Seed Bank: A Hidden Markov Model to Estimate Life History Traits from Standing Plant Time Series.

    Science.gov (United States)

    Borgy, Benjamin; Reboud, Xavier; Peyrard, Nathalie; Sabbadin, Régis; Gaba, Sabrina

    2015-01-01

    Predicting the population dynamics of annual plants is a challenge due to their hidden seed banks in the field. However, such predictions are highly valuable for determining management strategies, specifically in agricultural landscapes. In agroecosystems, most weed seeds survive during unfavourable seasons and persist for several years in the seed bank. This causes difficulties in making accurate predictions of weed population dynamics and life history traits (LHT). Consequently, it is very difficult to identify management strategies that limit both weed populations and species diversity. In this article, we present a method of assessing weed population dynamics from both standing plant time series data and an unknown seed bank. We use a Hidden Markov Model (HMM) to obtain estimates of over 3,080 botanical records for three major LHT: seed survival in the soil, plant establishment (including post-emergence mortality), and seed production of 18 common weed species. Maximum likelihood and Bayesian approaches were complementarily used to estimate LHT values. The results showed that the LHT provided by the HMM enabled fairly accurate estimates of weed populations in different crops. There was a positive correlation between estimated germination rates and an index of the specialisation to the crop type (IndVal). The relationships between estimated LHTs and that between the estimated LHTs and the ecological characteristics of weeds provided insights into weed strategies. For example, a common strategy to cope with agricultural practices in several weeds was to produce less seeds and increase germination rates. This knowledge, especially of LHT for each type of crop, should provide valuable information for developing sustainable weed management strategies.

  7. Seed bank modelling of volunteer oil seed rape: from seeds fate in the soil to seedling emergence Modelagem do banco de sementes de canola: do destino das sementes no solo à emergência das plântulas

    Directory of Open Access Journals (Sweden)

    E. Soltani

    2013-06-01

    Full Text Available Studies were conducted to estimate parameters and relationships associated with sub-processes in soil seed banks of oilseed rape in Gorgan, Iran. After one month of burial, seed viability decreased to 39%, with a slope of 2.03% per day, and subsequently decreased with a lower slope of 0.01 until 365 days following burial in the soil. Germinability remained at its highest value in autumn and winter and decreased from spring to the last month of summer. Non-dormant seeds of volunteer oilseed rape did not germinate at temperatures lower than 3.8 ºC and a water potential of -1.4 MPa ºd. The hydrothermal values were 36.2 and 42.9 MPa ºd for sub- and supra-optimal temperatures, respectively. Quantification of seed emergence as influenced by burial depth was performed satisfactorily (R² = 0.98 and RMSE = 5.03. The parameters and relationships estimated here can be used for modelling soil seed bank dynamics or establishing a new model for the environment.Estudos foram realizados para estimar os parâmetros e as relações ligados a subprocessos em bancos de sementes de canola no solo, em Gorgan, Iran. Após um mês de enterrio, a viabilidade das sementes diminuiu para 39%, com inclinação de 2,03% ao dia; posteriormente, diminuiu com menor inclinação: de 0,01 até 365 dias após o enterrio no solo. A germinação manteve-se em seu maior valor no outono e inverno, reduzindo da primavera ao último mês do verão. Sementes de canola não dormentes não germinaram em temperaturas abaixo de 3,8 °C e potencial hídrico abaixo de -1,4 Mpaºd. Os valores hidrotermais foram de 36,2 e 42,9 Mpaºd para temperaturas sub e supraótima, respectivamente. A quantificação da emergência das sementes sob influência da profundidade de enterrio foi delineada de forma satisfatória (R²= 0,98 e RMSE = 5,03. Os parâmetros e as relações estimadas neste estudo podem ser utilizados em modelagens do banco de sementes do solo ou para estabelecer um novo modelo para

  8. 桉树人工林土壤种子库研究%The Study on the Soil Seed Bank of Eucalyptus Plantation

    Institute of Scientific and Technical Information of China (English)

    唐庆兰; 朱宇林; 张照远; 刘建

    2012-01-01

    为了了解桉树人工林土壤种子库的物种组成、密度、垂直分布等特征,以2年生桉树人工林为研究对象,相邻的大叶栎人工林作对照,取其土壤,通过室内种子萌发的方法,研究桉树人工林土壤种子库分布特征.结果表明:(1)各土壤层种子萌发的规律基本一致,大约从第7天开始进入种子萌发高峰期,第19天萌发高峰期基本结束,随后进入缓慢萌发期,至最后停止萌发;(2)桉树人工林土壤种子库储量较大,种子密度为9804粒/m2(对照为3614粒/m2),共计物种15种,分属于9科,其中禾本科的弓果黍为优势种,种子密度为8849粒/m2,占土壤种子库总量90.26%;(3)种子库垂直分布格局显示,80%以上的种子储存在枯枝落叶层和0~5 cm的土壤中.2年生桉树人工林土壤种子库的种子密度大于大叶栎人工林,其组成以草本为主,灌木次之,种子多集中在枯枝落叶层和浅层土壤中.%In order to investigate the species composition, density and vertical distribution characteristics of the soil seed bank of Eucalyptus plantation, the growth of 2-year-old Eucalyptus plantation was researched in comparison with the nearby miscellaneous wood. Through the method of the interior of seed germination and taking their forest soil, the distribution characteristics of Eucalyptus plantation soil seed bank were studied. The results showed that: (1) the rate of seed germination was about the same rule from 7 days beginning to enter seed germination peak, 19 days to an end, then germination peak into the slow development to finally stop germination; (2) Eucalyptus plantation' s soil seed banks and seed density largely reserved for 9804 grain/m2 (control for 3614 grain/m2), a total of 15 species, belonging to 9 families, of which the Gramineae cyrtococcum as the dominant species with an seed density of 8849 grain/m2, accounting for 90.26% of total soil seed bank; (3) Seed bank vertical distribution pattern showed

  9. Soil seed bank during succession at an abandoned pasture in the upper Paraná river-floodplain, Brazil - doi: 10.4025/actascibiolsci.v33i1.6391 Soil seed bank during succession at an abandoned pasture in the upper Paraná river-floodplain, Brazil - doi: 10.4025/actascibiolsci.v33i1.6391

    Directory of Open Access Journals (Sweden)

    João Batista Campos

    2011-02-01

    Full Text Available We evaluated density and species composition of the soil seed bank in active pasture and in secondary forest on a 10 year-old abandoned pasture to identify changes in density, richness, diversity and species composition during secondary succession of abandoned pastures. The implications of those changes for the forest recovery process were also considered. Soil samples were collected at Porto Rico island, state of Paraná, in 2007. The seedling emergence method was used. Data on active pasture collected in 1996, published by Campos and Souza (2003 were used for comparative analysis. No evidence was found of a pattern of changes in density of the soil seed bank during succession of abandoned pastures. We observed increases in richness and diversity, in the contribution of tree and shrub species and dominance of herb species for the seed bank during the first 10 years of abandonment of pastures in riparian forests. At the end of succession, the soil used as pasture can result in systems that are different from the original environment, due to seed bank impoverishment and presence of exotic species.We evaluated density and species composition of the soil seed bank in active pasture and in secondary forest on a 10 year-old abandoned pasture to identify changes in density, richness, diversity and species composition during secondary succession of abandoned pastures. The implications of those changes for the forest recovery process were also considered. Soil samples were collected at Porto Rico island, state of Paraná, in 2007. The seedling emergence method was used. Data on active pasture collected in 1996, published by Campos and Souza (2003 were used for comparative analysis. No evidence was found of a pattern of changes in density of the soil seed bank during succession of abandoned pastures. We observed increases in richness and diversity, in the contribution of tree and shrub species and dominance of herb species for the seed bank during the

  10. Effects of water treatments on the activation of soil seed banks - A case study on the lower reaches of the Tarim River

    Institute of Scientific and Technical Information of China (English)

    Zengru Wang; Hailiang Xu; Linke Yin; Jimei Li; Zhanjiang Zhang; Yuan Li

    2009-01-01

    Evaluation of seedling emergence is a common method used to investigate the vegetation restoration potential of soil seed banks. Previous studies have primarily been conducted in the laboratory using a single water treatment. However, when this method is used, it is difficult to optimize the water conditions for the needs of the individual species of seeds. Additionally, the germination conditions for seedlings in the laboratory are different from those in nature. To avoid these issues, we conducted experiments to activate soil seed banks in the field using different water treatments. The results revealed that: (1) generally, the number of species and quantity of seedlings decrease gradually as the water supply decreases, but that for several species most seedlings did not appear when they were provided with the greatest amount of water, and (2) different species present different germination characteristics. According to the rate of seedling emergence, the species were classified into two germination types: fast and slow. In addition, each species also had a unique climax period of emergence, which was delayed with a decrease in water supply. Therefore, the amount of water provided is vital to seedling emergence, and various water treatments should be evaluated when studying the characteristics of different species in soil seed banks. For the lower reaches of the Tarim River, the optimal soil moisture for seedling emergence ranged from 23% to 28%, and seedling conservation should be strengthened during the climax period of emergence (9-15 days from the day when water became available). These results highlight the importance of the use of an optimal water treatment and demonstrate the danger of using a single treatment method. Our results also emphasize the need for a preliminary study prior to conducting studies to evaluate seed banks.

  11. Crude oil as a microbial seed bank with unexpected functional potentials

    Science.gov (United States)

    Cai, Man; Nie, Yong; Chi, Chang-Qiao; Tang, Yue-Qin; Li, Yan; Wang, Xing-Biao; Liu, Ze-Shen; Yang, Yunfeng; Zhou, Jizhong; Wu, Xiao-Lei

    2015-11-01

    It was widely believed that oil is a harsh habitat for microbes because of its high toxicity and hydrophobicity. However, accumulating evidence has revealed the presence of live microbes in crude oil. Therefore, it’s of value to conduct an in-depth investigation on microbial communities in crude oil. To this end, microorganisms in oil and water phases were collected from four oil-well production mixtures in Qinghai Oilfield, China, and analyzed for their taxonomic and functional compositions via pyrosequencing and GeoChip, respectively. Hierarchical clustering of 16S rRNA gene sequences and functional genes clearly separated crude oil and water phases, suggestive of distinct taxonomic and functional gene compositions between crude oil and water phases. Unexpectedly, Pseudomonas dominated oil phase where diverse functional gene groups were identified, which significantly differed from those in the corresponding water phases. Meanwhile, most functional genes were significantly more abundant in oil phase, which was consistent with their important roles in facilitating survival of their host organisms in crude oil. These findings provide strong evidence that crude oil could be a “seed bank” of functional microorganisms with rich functional potentials. This offers novel insights for industrial applications of microbial-enhanced oil recovery and bioremediation of petroleum-polluted environments.

  12. 铁路沿线沙区段植冠种子库对土壤种子库的补充及其种子活性变化%Supplement for the soil Seed Bank and Seed Viability of Canopy Seed Bank Along with the Railway Line of Sand Dune Areas

    Institute of Scientific and Technical Information of China (English)

    张晓妮; 马君玲; 韩蕾; 于慧; 王连峰

    2015-01-01

    通过野外监测和模拟试验,研究了铁路沿线沙区段3种沙生植物未埋藏直立植株个体的植冠种子库种子的季节脱落动态、植冠种子库对土壤种子库的补充动态及植冠储藏种子的活力和萌发特性。结果表明,(1)在风季即将结束生长季即将开始的时候,铁路沿线沙生植物差巴嘎蒿(Artemisia halodendron)的植冠种子库存留着最多的瘦果与头状花序,表现出将种子的脱落延迟到风季结束及雨季来临时的特点。推迟脱落传播体的时间表现为差巴嘎蒿大于冷蒿(A. frigida)和万年蒿(A. gmelinii),即随着沙丘流动性的增强,植冠种子库推迟脱落种子的程度逐渐增强。(2)植冠种子库对植株周围的土壤种子库起到补充作用,且差巴嘎蒿植冠种子库对土壤种子库的最大补充出现在风季结束雨季开始时期(种子成熟翌年5月)。(3)在风季即将结束雨季即将开始时,差巴嘎蒿植冠储藏种子80%以上具有活力,而冷蒿、万年蒿植冠储藏种子中有活力的种子占比不足20%。铁路沿线沙区段沙生植物的植冠种子库使种子的脱落及对土壤种子库的补充避开风季、迎合雨季,减少了由风季风蚀和沙埋所造成的种子损失,实现了种子的持续供应,同时以这种方式将保持活力的种子延迟至条件适宜时脱落并快速萌发,在一定程度上分摊了种群生存的风险,使种群得以持续繁衍。铁路沿线沙区段沙生植物独特的繁殖对策所反映出的生态功能对铁路沿线沙区段的土壤植被恢复研究具有重要的科学指导意义。%Seed (achene and capitulum) persistence on the parent plants, the supplement for the soil seed bank, and the maintenance of seed viability of 3 psammophyte were studied by means of field investigations and simulation experiments in sand dune areas along with the railway line. The results showed that: 1

  13. Production in aquatic macrophyte communities

    DEFF Research Database (Denmark)

    Binzer, Thomas; Sand-Jensen, Kaj

    2002-01-01

    Many terrestrial plant canopies regulate spatial patterns in leaf density and leaf inclination to distribute light evenly between the photosynthetic tissue and to optimize light utilization efficiency. Sessile aquatic macrophytes, however, cannot maintain the same well-defined three......-dimensional structure because of the strong drag and shear forces of moving water. This difference in canopy structure has been suggested to account for the three- to fivefold higher gross production rates in terrestrial than aquatic communities. To evaluate the effect of community structure in aquatic habitats, we...... was markedly enhanced by a vertical orientation of thalli when absorptance and community density were both high. This result implies that aquatic macrophytes of high thallus absorptance and community density exposed to high light are limited in attaining high gross production rates because of their inability...

  14. Production in aquatic macrophyte communities

    DEFF Research Database (Denmark)

    Binzer, Thomas; Sand-Jensen, Kaj

    2002-01-01

    -dimensional structure because of the strong drag and shear forces of moving water. This difference in canopy structure has been suggested to account for the three- to fivefold higher gross production rates in terrestrial than aquatic communities. To evaluate the effect of community structure in aquatic habitats, we...... to distribute photons evenly between the photosynthetic tissues. As scattering and attenuation in the water column increase, the effect of thallus structure on production declines and thin transparent macrophytes are more efficient at utilizing light than thick opaque macrophytes. The results confirm...... combined a simple mechanistic model and empirical measurements on artificially structured macroalgal communities (Ulva lactuca) with varying thallus absorptance and community density. Predicted and measured values corresponded closely and revealed that gross production in high-light environments...

  15. Characteristics of the Seed Banks and Seedling Banks of Mikania micrantha-Invaded Soils Different in Type of Habitat%不同生境薇甘菊土壤种子库与幼苗库的特征

    Institute of Scientific and Technical Information of China (English)

    申时才; 徐高峰; 张付斗; 李天林; 金桂梅; 张玉华

    2013-01-01

    通过野外定点取样与萌发试验相结合的方法,研究云南德宏州陇川县不同生境薇甘菊入侵地区的土壤种子库与幼苗库的特征.结果表明,根据土壤种子库萌发后的植物鉴定结果,橡胶林、林地、灌丛、草地和河岸边这5种生境共统计到40种植物,隶属18科.不同生境薇甘菊入侵群落的物种组成、种子萌发特性与空间分布及其幼苗库存在明显差异,橡胶林、林地、灌丛、草地和河岸边的薇甘菊种子密度分别为75、109、165、124和53粒·m-2,且各生境间差异显著(P<0.05).室内萌发试验表明,薇甘菊土壤种子库萌发时间持续8周,其中第3~5周的萌发速度最快;土壤垂直方向上,0~2、>2~5、>5~10 cm深度土层薇甘菊种子分别占0~10 cm土层种子总数的81%、17%和2%.野外薇甘菊土壤幼苗库萌发时间持续6个月(5-10月),其中6-8月萌发速度较快.%Characteristics were studied of the seed banks and seedling banks of the five places that are different in habitats but all invaded by M.micrantha in Longchuan County,Dehong Prefecture of Yunnan Province,China,using the method of field sampling and germination test in laboratory.Results show that seeds in the soil samples germinated and were identified to be of 40 plant species belonging to 18 families.They differed in species composition,characteristics and spatial distribution of seed germination and seedling bank between habitats.The M.micrantha seed density of rubber forest,woodlot,bushland,grassland,and river bank,the five different habitats,was 75,109,165,124,and 53 seed · m-2,respectively,showing significant difference between them (P<0.05).The in-laboratory germination experiment shows that germination of M.micrantha seeds may last for 8 weeks,and concentrated during the period from the 3rd to the 5th weeks.Vertically,its seeds were concentrated mainly in the 0-2 cm soil layer,and then in the >2-5 cm layer,and the >5-10 cm

  16. URJC GB dataset: Community-based seed bank of Mediterranean high-mountain and semi-arid plant species at Universidad Rey Juan Carlos (Spain).

    Science.gov (United States)

    Alonso, Patricia; Iriondo, José María

    2014-01-01

    The Germplasm Bank of Universidad Rey Juan Carlos was created in 2008 and currently holds 235 accessions and 96 species. This bank focuses on the conservation of wild-plant communities and aims to conserve ex situ a representative sample of the plant biodiversity present in a habitat, emphasizing priority ecosystems identified by the Habitats Directive. It is also used to store plant material for research and teaching purposes. The collection consists of three subcollections, two representative of typical habitats in the center of the Iberian Peninsula: high-mountain pastures (psicroxerophylous pastures) and semi-arid habitats (gypsophylic steppes), and a third representative of the genus Lupinus. The high-mountain subcollection currently holds 153 accessions (63 species), the semi-arid subcollection has 76 accessions (29 species,) and the Lupinus subcollection has 6 accessions (4 species). All accessions are stored in a freezer at -18 °C in Kilner jars with silica gel. The Germplasm Bank of Universidad Rey Juan Carlos follows a quality control protocol which describes the workflow performed with seeds from seed collection to storage. All collectors are members of research groups with great experience in species identification. Herbarium specimens associated with seed accessions are preserved and 63% of the records have been georreferenced with GPS and radio points. The dataset provides unique information concerning the location of populations of plant species that form part of the psicroxerophylous pastures and gypsophylic steppes of Central Spain as well as populations of genus Lupinus in the Iberian Peninsula. It also provides relevant information concerning mean seed weight and seed germination values under specific incubation conditions. This dataset has already been used by researchers of the Area of Biodiversity and Conservation of URJC as a source of information for the design and implementation of experimental designs in these plant communities. Since

  17. Seed rain, soil seed bank, and natural regeneration of natural Toona ciliata var.pubescens forest%毛红椿天然林种子雨、种子库与天然更新

    Institute of Scientific and Technical Information of China (English)

    黄红兰; 张露; 廖承开

    2012-01-01

    2008-2011年,调查江西九连山国家级自然保护区毛红椿天然林的种子雨、种子库及林下幼苗数量.结果表明:在毛红椿天然林,种子雨散布时间为10月下旬至12月下旬.2010年不同样地的种子雨强度为虾公塘气象观测站(320.3±23.5粒·m-2)>虾公塘保护站(284.7±24.2粒·m-2)>大丘田保护站(251.6±24.7粒·m-2),分别以222.0、34.3和22.6粒·m-2完好种子供土壤萌发更新;毛红椿种子储量取决于结实量、鸟类取食和种子活力等因素,鸟类取食是其种子储量大幅下降的首要因素;由于种子不耐储藏以及大量腐烂,种子有效贮藏期不足1个月.12月天然林种子库平均萌发数≤2株·m-2,次年1月土壤种子库种子量最少,为6.7~11.8粒·m-2,平均仅萌发0.4~0.6株·m-2,与林下实生幼苗分布极少相吻合.毛红椿种子雨储备、种子库种子活力保存及幼苗建成等因素影响其天然更新.%Taking the natural Toona ciliata var. pubescens forest in the Jiujiangshan National Nature Reserve in Jiangxi Province of China as test object, an investigation was conducted on the seed rain, soil seed bank, and seedlings number in 2008-2011. The seed rain of the forest was dispersed from late October to the end of December. In 2010, the seed rain intensity in different sampling plots was in the order of Xiagongtang observatory (320. 3+23. 5 seeds · m-2) > Xiagongtang protection station (284.7±24. 2 seeds · m-2) > Daqiutian protection station (251. 6±24. 7 seeds · m-2) , and the quantity of the intact seeds in soil supplied for seed germination and regeneration was 222. 0, 34. 3 , and 22.6 seeds · m-2 , respectively. The seed bank reserves was affected by the seed production amount, bird feeding, and seed viability, etc. , of which, bird feeding was the prime factor for the substantial drop of the seed bank reserves. Due to the low resistance against storage and a large number of rot during storage, the seeds in soil

  18. Macrophytes: Freshwater Forests of Lakes and Rivers.

    Science.gov (United States)

    McDermid, Karla J.; Naiman, Robert J.

    1983-01-01

    Physical, chemical, and biological effects on macrophytes (aquatic plants) on the freshwater ecosystem are discussed. Research questions and issues related to these organisms are also discussed, including adaptations for survival in a wet environment, ecological consequences of large-scale macrophyte eradication, seasonal changes in plant…

  19. Banco de sementes de aveia preta no solo sob dois sistemas de manejo Soil seed bank of black oat in two management systems

    Directory of Open Access Journals (Sweden)

    Marcos Paulo Ludwig

    2011-01-01

    Full Text Available As sementes de aveia preta (Avena strigosa Schreb. possuem a capacidade de permanecer viáveis no solo de um ano de cultivo para outro. Dessa forma, o objetivo do trabalho foi avaliar o número de sementes de aveia preta resultantes de dois sistemas de manejo (colheita e ressemeadura natural, que poderão formar o banco de sementes do solo. Os ensaios foram realizados no município de Jari - RS, em uma área cultivada sob o sistema de "plantio direto". Foram coletadas 50 amostras em cada sistema de manejo, com um espaçamento de 10x20m, utilizando um amostrador de diâmetro de 0,05m e uma profundidade de 0,1m. O levantamento do número de sementes e da emergência das plântulas foi realizado no Laboratório Didático da Faculdade de Agronomia Eliseu Maciel (UFPel. Constatou-se que a colheita e a ressemeadura natural possibilitam a presença de sementes no solo por área, em quantidades superiores à indicada para a semeadura. Com a colheita, a área fica heterogênea em número de sementes no solo e em plântulas emergidas. A ressemeadura natural resulta em uma grande quantidade de sementes no solo e formação de plântulas.The black oat (Avena strigosa Schreb. seeds are able to remain alive in soil from a culture to another. The objective of this study was to evaluate the number of black oat seeds resulting from two management, harvesting, and natural reseeding, which could form the seed bank of soil. The experiments were conducted in Jari-RS, Brazil, the cultivation system is "No Tillage". Were collected 50 samples in each management, at a spacing of 10mx20m, using a sampler diameter of 0.05m and depth of 0.1m. The evaluation of the number of seeds and seedling emergence was accomplish at the Laboratory of Seeds Analysis of the Faculdade de Agronomia "Eliseu Maciel" (UFPEL. It was found that both as the crop as the natural seeding allow large quantities of seeds in the soil for the upper area suitable for planting. The harvest area is

  20. Determination of Algae and Macrophyte Species Distribution in Three Wastewater Stabilization Ponds Using Metagenomics Analysis

    Directory of Open Access Journals (Sweden)

    Jack Wallace

    2015-06-01

    Full Text Available This study involved the evaluation of algae and macrophyte species distributions in three wastewater stabilization ponds (WSPs at a wastewater treatment plant in Ontario, Canada, which has experienced high pH levels at the final effluent and excessive algae growth during the summer since 2003. From samples collected from the system, the relative abundances of specific algae and aquatic plant (macrophyte taxa were assessed and correlated to water chemistry data. A strong shift from the dominance of green algae, chlorophyceae, in WSP#2, to the dominance of aquatic macrophytes, embryophyta, in WSP#4, was observed and corresponded to field observations. Correlation of the abundances to nutrient parameters suggested that the macronutrient rich conditions in WSP#2 allowed floating green algae to proliferate against macrophytes. In WSP#1 and WSP#4, macrophytes competed against algae and thrived, due to their adaptability to lower nutrient conditions. The pH increases occurred primarily in WSP#2 and were not buffered or reduced in WSP#1 and WSP#4. Two alternatives strategies for pH control were recommended for the system: decreasing algae growth in WSP#2 through duckweed seeding or macronutrient loading reduction; or designing and implementing a constructed wetland (CW in WSP#4 with soil and vegetation to buffer pH prior to release.

  1. BANCO DE SEMILLAS EN UN BOSQUE DE ROBLE DE LA CORDILLERA CENTRAL COLOMBIANA SOIL SEED BANK IN AN OAK FOREST FROM THE COLOMBIAN CENTRAL CORDILLERA

    Directory of Open Access Journals (Sweden)

    Luz Bibiana Moscoso Marín

    2005-12-01

    Full Text Available El banco de semillas del suelo es importante para el funcionamiento del ecosistema, pues se constituye en un reservorio de especies listas a germinar cuando se presenta una perturbación o cuando las condiciones ambientales cambian para iniciar el proceso de sucesión. El objetivo principal de esta investigación fue evaluar la variación espacial del banco de semillas y su relación con la vegetación actual en un fragmento de bosque altoandino dominado por roble de tierra fría (Quercus humbodtii Bonpl. a 2.290 m.s.n.m. en la cuenca de la Quebrada Piedras Blancas, en el departamento de Antioquia, Colombia. Allí se estableció una parcela de 6.400 m², donde se eligieron 57 puntos de muestreo. En cada uno de ellos se colectó una muestra de hojarasca y una de suelo. Además se marcaron cinco subparcelas de 160 m²para hacer el muestreo de la vegetación. La determinación del banco de semillas se hizo por el método de germinación directa, evaluando la emergencia de plántulas. En total, se censaron 204 individuos pertenecientes a 25 familias y 41 géneros. Las especies con mayor representación fueron Alfaroa cf. colombiana, Myrcia popayanensis Rich. y Quercus humboldtii Bonpl. En el ensayo de germinación se obtuvieron 428 individuos en las muestras de suelo y 113 en las de hojarasca, pertenecientes a 20 morfoespecies. La composición de especies del banco de semillas de este fragmento de robledal, no reflejó la composición actual de la vegetación del bosque. El banco de semillas esta constituido principalmente por especies herbáceas y en menor proporción por arbustos. La hojarasca contiene poca cantidad de semillas (198 semillas m-2 y en los primeros 10 cm del suelo se acumula una gran cantidad de semillas viables (4.330 semillas m-2. Se presenta una variación espacial significativa en la densidad de semillas del suelo a través del bosque a escala de unos pocos metros.Soil seed banks are important for ecosystem functioning because

  2. The correlation between Prorocentrum donghaiense blooms and the Taiwan warm current in the East China Sea - evidence for the "Pelagic Seed Bank" hypothesis.

    Directory of Open Access Journals (Sweden)

    Xinfeng Dai

    Full Text Available During the last two decades, large-scale high biomass algal blooms of the dinoflagellate Prorocentrum donghaiense Lu have occurred frequently in the East China Sea (ECS. The role of increasing nutrient concentrations in driving those blooms is well-established, but the source population that initiates them is poorly understood. We hypothesized that the front of Taiwan Warm Current (TWC may serve as a 'seed bank' that initiates P. donghaiense blooms in the ECS, as the physiochemical conditions in the TWC are suitable for the growth of P. donghaiense. In order to test this hypothesis, two surveys at different spatio-temporal scales were conducted in 2010 and 2011. We found a strong correlation in space and time between the abundance of P. donghaiense and the TWC. The spatial extent of the P. donghaiense bloom coincided with the TWC front in both 2010 and 2011. During the early development of the blooms, P. donghaiense concentration was highest at the TWC front, and then the bloom mass shifted inshore over the course of our 2011 survey. The TWC also moved inshore, albeit after the appearance of P. donghaiense. Overall, these results support our hypothesis that P. donghaiense blooms develop from the population at the TWC front in the ECS, suggesting the role of the ocean current front as a seed bank to dinoflagellate blooms.

  3. A macrophyte submodel for aquatic ecosystems

    Science.gov (United States)

    Collins, Carol Desormeau; Wlosinski, Joseph H.

    1989-01-01

    A macrophyte submodel has been incorporated and tested in CE-QUAL-R1, a one-dimensional, vertically averaged model of reservoir water quality. A quasi two-dimensional scheme was necessary to represent the spatial relationship of macrophytes in reservoirs adequately. The macrophyte processes modeled were photosynthesis, dark respiration, excretion and nonpredatory mortality. Process equations for photosynthesis as a function of light and temperature, and dark respiration as a function of temperature were tested using data from laboratory studies. The submodel was field tested, along with other components of CE-QUAL-R1, using data collected at Eau Galle Reservoir, WI, U.S.A.

  4. Windows of opportunity for germination of riparian species after restoring water level fluctuations: a field experiment with controlled seed banks

    NARCIS (Netherlands)

    Sarneel, J.M.; Janssen, R.H.; Rip, W.J.; Bender, I.; Bakker, E.S.

    2014-01-01

    Restoration activities aiming at increasing vegetation diversity often try to stimulate both dispersal and germination. In wetlands, dispersal and germination are coupled as water and water level fluctuations (WLF) simultaneously influence seed transport and germination conditions (soil moisture). W

  5. Windows of opportunity for germination of riparian species after restoring water level fluctuations : a field experiment with controlled seed banks

    NARCIS (Netherlands)

    Sarneel, Judith M.; Janssen, Roel H.; Rip, Winnie J.; Bender, Irene M. A.; Bakker, Elisabeth S.

    2014-01-01

    1. Restoration activities aiming at increasing vegetation diversity often try to stimulate both dispersal and germination. In wetlands, dispersal and germination are coupled as water and water level fluctuations (WLF) simultaneously influence seed transport and germination conditions (soil moisture)

  6. Community photosynthesis of aquatic macrophytes

    DEFF Research Database (Denmark)

    Binzer, T.; Sand-Jensen, K.; Middelboe, A. L.

    2006-01-01

    We compared 190 photosynthesis-irradiance (P-E) experiments with single- and multispecies communities of macroalgae and vascular plants from freshwater and marine habitats. We found a typical hyperbolic P-E relation in all communities and no sign of photosaturation or photoinhibition of photosynt......We compared 190 photosynthesis-irradiance (P-E) experiments with single- and multispecies communities of macroalgae and vascular plants from freshwater and marine habitats. We found a typical hyperbolic P-E relation in all communities and no sign of photosaturation or photoinhibition...... of photosynthesis at the highest irradiances of about 2,000 mmol m22 s21. Macrophyte communities displayed much higher maximum gross production (GPmax), respiration, and light compensation point than separate phytoelements because of the multilayered structure and extensive self-shading in the communities, whereas...

  7. Community photosynthesis of aquatic macrophytes

    DEFF Research Database (Denmark)

    Binzer, T.; Sand-Jensen, K.; Middelboe, A. L.

    2006-01-01

    We compared 190 photosynthesis-irradiance (P-E) experiments with single- and multispecies communities of macroalgae and vascular plants from freshwater and marine habitats. We found a typical hyperbolic P-E relation in all communities and no sign of photosaturation or photoinhibition of photosynt......We compared 190 photosynthesis-irradiance (P-E) experiments with single- and multispecies communities of macroalgae and vascular plants from freshwater and marine habitats. We found a typical hyperbolic P-E relation in all communities and no sign of photosaturation or photoinhibition...... of photosynthesis at the highest irradiances of about 2,000 mmol m22 s21. Macrophyte communities displayed much higher maximum gross production (GPmax), respiration, and light compensation point than separate phytoelements because of the multilayered structure and extensive self-shading in the communities, whereas...

  8. Studies on Characteristics of Soil Seed Bank of Pedicularis verticilata Community%轮叶马先蒿群落土壤种子库特征研究

    Institute of Scientific and Technical Information of China (English)

    柳妍妍; 胡玉昆; 王鑫; 公延明; 李凯辉

    2011-01-01

    Pedicularis verticilata has already become an intrusion species on Bayanbulak grassland with the biological characteristics of small and excessive seed. In order to control its expansion effectively, the distribution characteristics and the relation with habitats of P. verticilata were studied by field vegetable investigation and laboratory testing analysis. We studied the characteristics of horizontal distribution on soil moisture gradient and the characteristics of vertical distribution under the conditions of different soil types by counting method. Constant temperature and varying temperature treatment methods were used from laboratory germination, P. verticilata' s seed germination response to temperature was analyzed. Correlation analysis was used to analyze the relationship between P. verticilata' s seed bank and plant diversity and other soil factors. The result shows that: 1 ) Soil water content is the main influencing factor for P. verticilata seed' s horizontal distribution. The order of vertical distribution of the seed is litter layer > humus layer > subsoil layer, the amount of seed difference was remarkable between each layer. 2) The amount of seed has a significant positive correlation with P. verticilata' s density and coverage, but has little correlation with other plants. 3) Regarding reproduction and growth, soil water content is the limiting factor. The number of inflorescence and the amount of seed reached maximum when soil water content is 0. 25, and no seed will be reproduced seed when soil water content exceeded P. verticilata' s tolerance limitation. Varying temperature is propitious to seed germination, the last ten-day of May and the first ten-day of June were the optimum period of germination, the germination rate reached to 76. 9% and 72.4%. 4) Soil organic matter is another main influencing factor for the growth and reproduction of P. verticilata, the correlation coefficient is 0. 970 (p <0. 01 ).%轮叶马先蒿种子小,

  9. Establishment and stability of seed bank of recombinant hepatitis E vaccine%重组戊型肝炎疫苗菌种库的建立及其稳定性

    Institute of Scientific and Technical Information of China (English)

    曹玉锋; 王伟善; 徐军; 时成波; 孟多佳; 迟春萍; 王玉梅; 贾媛; 张剑锋; 常东英

    2012-01-01

    Objective To establish three-tier seed bank of recombinant hepatitis E vaccine and study its stability. Methods Recombinant E. coli HEV179/BL21 (DE3) was resuscitated, activated and subjected to overall control tests, and the qualified ones were lyophilized as primary seed bank. The seeds from primary seed bank were subcultured, propagated and subjected to overall control tests, while the qualified ones were lyophilized as master seed bank. The seeds from master seed bank were subcultured, propagated and subjected to overall tests, while the qualified ones were cryopreserved in glycerol and served as working seed bank. The three-tier seed bank was subjected to overall control tests, and the recombinant strain was evaluated for stabilities after lyophilization and cryopreservation in glycerol as well as the genetic stability. Results The established three-tier seed bank was qualified in overall control tests, of which the stabilities after lyophilization and cryopreservation in glycerol as well as the genetic stability met the relevant requirements. The growth characteristics as well as genetic and expression stabilities of recombinant strain showed no significant change. Conclusion Three-tier seed bank of HEV179 / BL2l(DE3) was successfully established, and the seeds showed high stability and was suitable for industrial production of recombinant hepatitis E vaccine.%目的 建立重组戊型肝炎疫苗工程菌三级种子库,并分析其稳定性.方法 将工程菌株HEV179/BL21 (DE3)复苏活化,经全面检测合格后冻干保存即为原始种子库;原始种子库传代扩增,经全面检定合格后,冻干保存即为主种子库;主种子库经传代扩增和全面检定合格后,甘油冻存即为工作种子库.对三级种子库进行全面检定,并对工程菌进行冻干及甘油冻存稳定性、甘油冻存时间稳定性及质粒稳定性检测.结果 建立的三级种子库经全面检定合格;菌种冻干稳定性、甘油冻存稳定

  10. Macrophytes: ecosystem engineers in UK urban rivers

    Science.gov (United States)

    Gibbs, H.; Gurnell, A.; Heppell, K.; Spencer, K.

    2012-04-01

    Macrophytes act as ecosystem engineers within river channels in that they have the ability to cause geomorphological and ecological change. They induce reductions in flow velocity and associated sediment accumulation, and their system of underground roots and rhizomes also reinforces the accumulated sediment reducing sediment erosion and resuspension and creating habitats. As sediments, particularly finer-grained, store contaminants including metals, this engineering means that in the specific context of urban rivers where sediments are more likely to be contaminated, macrophytes trap and hold contaminated sediments creating a potentially important sink of metals. However, depending on the ability for the macrophyte to reinforce the sediment and reduce erosion and resuspension, there is the potential for the sink to turn in to a source and metals to be released in to the overlying water. This research therefore looks at the ecosystem engineering ability of common macrophytes in UK urban rivers by looking at: (i) the effect upon flow velocity and sediment accumulation of Sparganium erectum (branched bur-reed); (ii) the sediment reinforcement ability of both S. erectum, Typha latifolia (bulrush) and Phalaris arundinacea (reed canary grass); and, (iii) the storage of metals within the sediment, overlying water and the macrophytes. Research was undertaken on the River Blackwater, an urban river in Surrey, UK which has extensive macrophyte growth. Flow velocity measurements and fine sediment depths were recorded both within and outside of dense stands of S. erectum. The uprooting resistance (as an indicator of sediment reinforcement) was measured for three species: S. erectum, T. latifolia and P. arundinacea. Additionally, some preliminary sampling was undertaken of the sediment, overlying water and the macrophytes to determine metal storage. Lower flow velocities and greater volumes of fine sediment were recorded within the stands of S. erectum as opposed to the

  11. Seed falling and seed bank research on natural Pinus sylvestris var.mongolica individual plant in the Hulun Buir sandy land%呼伦贝尔沙地樟子松落种与种子库特征

    Institute of Scientific and Technical Information of China (English)

    王妍; 卢琦; 王玉华; 敖文明; 乔殿学

    2012-01-01

    Pinus sylvestris var. mongolica is adaptive to cold, drought and barren environment, with prominent regeneration ability to wind erosion control and shifting sand fixed. The natural regeneration process of Pinus sylvestris var. mongolica in the sandy land is important to vegetation rehabilitation, degraded ecosystems reconstruction, sustainable sandy ecosystem benefit development, as well as the establishment of green ecological barriers in north of China. In order to explore seed bank and seed falling of Pinus sylvestris var. mongolica, inoculators (specification: 1.0 m × 1.0 m × 0.1 m) were installed at 4, 8, 12 m in easi/south/west/ north direction from the mature tree and grids (specification; 1 m × 1 m) were arranged around the mature tree, and with the vectoring technology get the spatial distribution graph which X axle is north direction axle is east direction. The results showed that Pinus sylvestris var. mongolica seeds disperse mainly in the litter layer with an average seed density of 614 seeds·m-2 and in the 0-5 cm horizon with an average seed density of 469 seeds·m-2. The amount of seeds in different direction respectively is 6.67 (east)>6.07 (north) >5.53(west)> 4.63 (north). The primary dispersal concentration was up to about 3 m from the mature tree. Temperate and spatial characteristics of seed falling showed that most seeds were in a region near the mature tree, especially in the 0-8 m range. Conclusions were drawn that the seeds of Pinus sylvestris var. mongolica dispersal density near the observed tree was fan-shaped and composed by winds from the south and west. The horizontal distribution characteristics of seed bank from a nature tree shaped a ring region where seed density was largest from the north to the east with seed density decreasing as the distance increased from the mature tree. [ Ch, 4 fig. 1 tab. 18 ref.]%采用生态学方法对呼伦贝尔沙地樟子松Pinus sylvestris var.mongolica土壤种子库和落种情况进行调

  12. DNA barcoding for conservation, seed banking and ecological restoration of Acacia in the Midwest of Western Australia.

    Science.gov (United States)

    Nevill, Paul G; Wallace, Mark J; Miller, Joseph T; Krauss, Siegfried L

    2013-11-01

    We used DNA barcoding to address an important conservation issue in the Midwest of Western Australia, working on Australia's largest genus of flowering plant. We tested whether or not currently recommended plant DNA barcoding regions (matK and rbcL) were able to discriminate Acacia taxa of varying phylogenetic distances, and ultimately identify an ambiguously labelled seed collection from a mine-site restoration project. Although matK successfully identified the unknown seed as the rare and conservation priority listed A. karina, and was able to resolve six of the eleven study species, this region was difficult to amplify and sequence. In contrast, rbcL was straightforward to recover and align, but could not determine the origin of the seed and only resolved 3 of the 11 species. Other chloroplast regions (rpl32-trnL, psbA-trnH, trnL-F and trnK) had mixed success resolving the studied taxa. In general, species were better resolved in multilocus data sets compared to single-locus data sets. We recommend using the formal barcoding regions supplemented with data from other plastid regions, particularly rpl32-trnL, for barcoding in Acacia. Our study demonstrates the novel use of DNA barcoding for seed identification and illustrates the practical potential of DNA barcoding for the growing discipline of restoration ecology.

  13. 植物遗传资源的种子基因库保存%Ex Situ Conservation of Plant Genetic Resources through Seed-Gene Bank

    Institute of Scientific and Technical Information of China (English)

    唐安军; 宋松泉; 龙春林

    2007-01-01

    behavior,it is necessary to consider three principal factors:storage environment,storage duration and plant species which will affect seed survival under good genebanking conditions.The present review is an attempt to discuss the importance of the aforementioned aspects of seeds in detail in order to conserve plant germplasms (especially wild rare and endangered plants) for ex situ conservation through seed-gene bank.

  14. Floristic diversity of the soil weed seed bank in a rice-growing area of Brazil: in situ and ex situ evaluation

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    Mário Luiz Ribeiro Mesquita

    2013-09-01

    Full Text Available The objective of this study was to compare the ex situ and in situ floristic diversity of the soil weed seed bank of a rice field in northeastern Brazil. In a rice field in the county of Bacabal, located in the state of Maranhão, thirty 25-m² plots were laid out. From 15 plots, soil samples (6/plot; n = 90 were taken with a soil probe (25 × 16 × 3 cm and placed in aluminum trays in the greenhouse. From the remaining 15 plots, weed samples (6/plot; n = 90 were taken with the same soil probe. The number of seeds was estimated by germination. We evaluated the numbers of species and individuals, as well as the density, frequency, abundance and importance value (IV for each species. Diversity was computed by the Shannon index (H'. We recorded 13,892 individuals (among 20 families, 40 genera and 60 species, of which 11,530 (among 50 species germinated ex situ and 2,362 (among 34 species germinated in situ. The family Cyperaceae had the highest number of species (16, followed by Poaceae (10. The dominant species, in situ and ex situ, were Schoenoplectus juncoides (IV=47.4% and Ludwigia octovalvis (IV=34.8%, respectively. Floristic diversity was higher ex situ (H'=2.66. The information obtained here could help determine the infestation potential of these species, which could lead to improved management strategies.

  15. Effects of woody species encroachment and fire on the soil seed bank of Transylvanian dry basiphilous grasslands - perspectives for their restoration

    Science.gov (United States)

    Görzen, Eugen; Borisova, Karina; Ruprecht, Eszter; Fenesi, Annamária; Lukács, Katalin; Bertram, Anna; Donath, Tobias W.

    2017-04-01

    Background: Semi-natural dry basiphilous grasslands in the Transylvanian Basin of Romania are among the most species-rich grasslands worldwide and protected according to the Habitats Directive of the European Union. They evolved in response to human impact over millennia (grazing and cutting) and to prevailing environmental conditions. Currently, they are under threat due to land use changes: abandonment and intensification of sheep farming. As soon as the management of the grassland ceases, litter accumulation begins, followed by the invasion and establishment of native and non-native shrubs and trees. In order to halt secondary succession, the deliberate burning of shrub-encroached grasslands has progressively been applied. Questions: The establishment of woody species in grassland as well as the application of fire management to prevent the further spread of shrubs has recently increased in Transylvania. Still, little is known about the underlying mechanisms and the specific effects of encroachment by native and non-native woody species as well as fire on plant species and functional diversity of these grasslands. Likewise, there is a lack in efficient measures in Transylvania to restore grassland already invaded by woody plants. Consequently, we ask: (i) In which ways does woody species encroachment affect plant species and functional diversity, (ii) do native and non-native woody species differ with respect to their impact on grassland species composition and structure, (iii) is controlled burning a useful management tool to control shrub encroachment and to preserve biodiversity of these grasslands, and (iv) can soil seed banks contribute to the restoration of dry basiphilous grasslands in Transylvania? Methods: We collected data on plant species richness, composition and structure, topsoil conditions and soil seed bank composition in 16 shrub encroached grassland sites in the Transylvanian Basin, Romania, from June to August 2016. We compared uninvaded

  16. The soil seed bank in abandoned tropical pastures: source of regeneration or invasion? El banco de semillas en pastizales tropicales abandonados: fuente de regeneración o de invasión?

    Directory of Open Access Journals (Sweden)

    Leonel López-Toledo

    2011-06-01

    Full Text Available We assessed the availability of both pioneer and non-native species in the soil seed bank of old-growth forest and recently abandoned pasture, to evaluate whether the soil seed bank in these pastures represents a source of regeneration of species from adjacent old-growth forest or of invasion by non-native species. Our study was conducted at Selva Lacandona, Chiapas, Mexico. Soil samples were randomly collected from 6 sites in old-growth forest, and 6 sites in abandoned pastures. Seedlings from soil samples were identified and classified into pioneer, non-native (weeds/graminoids, and other forest species. Pioneer species seeds were virtually absent in pastures, but represented ~30% of seeds in the forest. Non-native species comprised ~99% of the soil seed bank in pastures. In the forest, soil seed bank density of weeds and graminoids decreased with increasing distance (up to 4 km from agricultural fields, and comprised up to 25% (Mean ± 1SE= 16 ± 7 of the seed bank. Our results show a near total elimination of pioneer species from the soil seed bank in pastures, and considerable invasion of the borders of the Montes Azules reserve by seeds of non-native species. Thus, in the region studied, the soil seed bank in abandoned pastures represents a source of invasion by non-native species into old-growth forest rather than a potential source of forest regeneration.Para evaluar si el banco de semillas en pastizales abandonados representa una fuente de regeneracion o de invasión por especies no-nativas para el bosque maduro se evaluó la presencia de especies pioneras y no-nativas en el banco de semillas de bosque maduro y pastizales recien abandonados en la selva lacandona, Chiapas, México. Se recolectaron muestras de suelo en 6 sitios de bosque maduro y de pastizales abandonados. Las semillas germinadas fueron identificadas y clasificadas en especies pioneras, no-nativas (malezas/graminoides y otras especies de bosque. Las especies pioneras

  17. BANCO DE SEMENTES DE PLANTAS DANINHAS EM SOLO CULTIVADO COM ADUBOS VERDES WEED SEED BANK IN GREEN-MANURE-CULTIVATED FIELDS

    Directory of Open Access Journals (Sweden)

    FRANCISCO JOSÉ SEVERINO

    2001-01-01

    Full Text Available Com o objetivo de estudar a composição de banco de sementes de plantas daninhas em solo cultivado com adubos verdes, desenvolveu-se um experimento em casa de vegetação do Departamento de Produção Vegetal da Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ/USP, Piracicaba (SP, entre dezembro de 1999 e fevereiro de 2000. As parcelas experimentais, compostas de 1 kg de solo amostrado por um trado de 4,3 cm de diâmetro, a partir da experimentação em campo, foram instaladas em bandejas de 30 x 20 x 5 cm. O delineamento experimental adotado foi o de blocos ao acaso com quatro repetições constando dos fatores: a adubos verdes - amendoim-forrageiro (Arachis pintoi Krapov. & W.C. Gregory, crotalária (Crotalaria juncea L., guandu-anão [Cajanus cajan (L. Millsp.] e testemunha sem capina; b plantas daninhas - capim-braquiária (Brachiaria decumbens Stapf., capim-colonião (Panicum maximum Jacq., picão-preto (Bidens pilosa L., além da vegetação espontânea. Avaliou-se o número de plantas daninhas emergidas aos 30 e 60 dias após a instalação do experimento. Os resultados permitem concluir que o banco de sementes de plantas daninhas foi significativamente reduzido com a utilização dos adubos verdes, constituindo em prática agrícola relevante para o manejo integrado de plantas daninhas.In order to evaluate the composition of a weed seed bank in a soil cultivated with green manure, an experiment was carried out from December, 1999, to February, 2000, in a greenhouse of the Plant Production Department, ESALQ/University of São Paulo, Piracicaba, Brazil. The experimental units were made of 30 x 20 x 5 cm trays, filled with 1.0 kg of soil. The soil was collected by a 4.3 cm core sampler from the experimental field where the green manure and weeds were grown. The experiment had a completely randomized block design with four replicates, green manure (Arachis pintoi Krapov. & W.C. Gregory, Crotalaria juncea L. and Cajanus cajan L

  18. Banco de sementes e estabelecimento de plantas daninhas em agroecossistemas Seed bank in the soil and the establishment of weeds in agro-ecosystems

    Directory of Open Access Journals (Sweden)

    Ricardo Carmona

    1995-01-01

    Full Text Available Em novembro/92 o banco de sementes no solo foi estimado, a 0-10 cm de profundidade, em alguns agroecossistemas: área de rotação de culturas, várzea, pomar de cítrus e pastagem de Brachiaria brizantha, no Distrito Federal, Brasil. Esta estimativa foi realizada através da observação da emergência de plântulas em amostras de solo incubadas, com e sem lavagem através de peneira e presença ou ausência de nitrato de potássio. A lavagem do solo para redução de volume, seguida de utilização de nitrato de potássio, mostrou-se desvantajosa para a determinação dos bancos de sementes viáveis detectadas nas amostras. A quantidade média de sementes por metro quadrado foi de 22313 na várzea, 6768 na área de rotação, 3595 nas coroas do pomar e 529 na pastagem. Verificou-se que as plantas infestantes estabelecidas em maio/93 nos agroecossistemas, representavam, em relação á quantidade inicial de sementes: 0,34% na pastagem, 0,71% na várzea, 1,48% nas coroas do pomar e 1,56% na área de rotação de culturas. Estas plantas seriam aquelas que supostamente mais contribuíram para a manutenção dos bancos de sementes no solo. Houve uma correlação direta do banco de sementes com o número de espécies e indivíduos presentes nos agroecossistemas. As espécies predominantes nas áreas anualmente perturbadas foram Ageratum conyzoides, Bidens pilosa, Cenchrus echinatus, Commelina benghalensis, Emilia sonchifolia, Euphorbia heterophylla e Richardia brasiliensis. Brachiaria spp predominou nas entrelinhas do pomar, enquanto na pastagem as poucas plantas daninhas presentes eram espécies de cerrado. A similaridade entre agroecossistemas, com relação às plantas daninhas foi maior entre as áreas mais perturbadas, como áreas de rotação de culturas, várzea e coroas do pomar.The seed bank in the soil was estimated in November/92 at 0-10 cm depth in some agro-ecosystems: arable land, meadow land, citrus orchard and a Brachiaria brizantha

  19. Seed predation in a Mediterranean pasture: can ants modify the floristic composition of soil seed banks? Depredación de semillas en un pastizal mediterráneo: ¿pueden las hormigas modificar la composición florística de los bancos de semillas?

    Directory of Open Access Journals (Sweden)

    TÍSCAR ESPIGARES

    2005-12-01

    Full Text Available Ants may play an important role on vegetation dynamics, especially in arid and semiarid environments, where they can consume a high proportion of the produced seeds. Although some works have analysed the influence of seed predation by ants on the density of vegetation in Mediterranean pastures, there are no studies on the influence of ant activity upon the floristic composition of the vegetation and the soil seed banks in this kind of ecosystem. We have studied the effect of ant exclusion on the floristic composition of the vegetation and the soil seed bank in a Mediterranean pasture of central Spain. We sampled the floristic composition of the pasture during 2002 and 2003 springs and also we collected soil seed bank samples in autumn 2002. Floristic composition of soil seed banks was estimated by means of greenhouse germination. Cerastium semidecandrum seeds were almost four times more abundant in the plots subjected to ant exclusion than in those with ant activity. Due to the high spatial heterogeneity shown by soil seed banks, we have corrected the differences found between the autumn soil seed banks subjected to different ant treatments by using the floristic composition of the pasture community in the previous spring, as it was the primary source of the seeds collected in autumn. We found significant differences between the floristic composition of the soil seed banks subjected to ant exclusion and control treatments. However, no effects where found when the same procedure was used to detect ant effects on the spring adult community, highlighting the necessity of longer time spans for these pastures to manifest changes taking place at the soil seed bank stageLa mirmecofauna juega un papel fundamental sobre la dinámica de la vegetación, especialmente en zonas de carácter árido o semiárido, donde puede llegar a consumir una elevada proporción de las semillas producidas, condicionando la composición florística de la vegetación. Aunque

  20. Soil weed seed bank in situ and ex situ at a smallholder field in Maranhão State, northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Mário Luiz Ribeiro Mesquita

    2014-11-01

    Full Text Available The objective of this research was to assess the density, floristic composition,  phytosociology and diversity of a soil weed seed bank ex situ by germination in a greenhouse and in situ by weed sampling on a smallholder corn field located in Lago Verde County, Maranhão State. Fifteen pairs of 25 m2 plots were designated. In half of these plots, 90 soil samples were collected with an open metal template measuring 25 x 16 x 3 cm and placed in a greenhouse to germinate. In the other half, 90 weed samples were collected using the same metal template. We recorded a total of 1,998 individuals from 40 species, 31 genera and 16 families, from which 659 individuals germinated in situ and 1,339 exsitu. Density was higher ex situ, with 372 plants m-2. The Cyperaceae family had the highest floristic richness with nine species, followed by the Poaceae with six. The dominant species based on the Importance Value Index were Lindernia crustacea (IVI 27.7% in situ and Scleria lithosperma (IVI 37.0% ex situ. Floristic diversity was higher ex situ, with H’ = 2.66 nats ind-1. These results could help predict infestation potential and could lead to improved weed management strategies in corn-growing areas on smallholdings in Maranhão State, northeastern Brazil.

  1. AMEG: the new SETAC advisory group on aquatic macrophyte ecotoxicology.

    Science.gov (United States)

    Arts, Gertie; Davies, Jo; Dobbs, Michael; Ebke, Peter; Hanson, Mark; Hommen, Udo; Knauer, Katja; Loutseti, Stefania; Maltby, Lorraine; Mohr, Silvia; Poovey, Angela; Poulsen, Véronique

    2010-05-01

    Primary producers play critical structural and functional roles in aquatic ecosystems; therefore, it is imperative that the potential risks of toxicants to aquatic plants are adequately assessed in the risk assessment of chemicals. The standard required macrophyte test species is the floating (non-sediment-rooted) duckweed Lemna spp. This macrophyte species might not be representative of all floating, rooted, emergent, and submerged macrophyte species because of differences in the duration and mode of exposure; sensitivity to the specific toxic mode of action of the chemical; and species-specific traits (e.g., duckweed's very short generation time). These topics were addressed during the workshop entitled "Aquatic Macrophyte Risk Assessment for Pesticides" (AMRAP) where a risk assessment scheme for aquatic macrophytes was proposed. Four working groups evolved from this workshop and were charged with the task of developing Tier 1 and higher-tier aquatic macrophyte risk assessment procedures. Subsequently, a SETAC Advisory Group, the Macrophyte Ecotoxicology Group (AMEG) was formed as an umbrella organization for various macrophyte working groups. The purpose of AMEG is to provide scientifically based guidance in all aspects of aquatic macrophyte testing in the laboratory and field, including prospective as well as retrospective risk assessments for chemicals. As AMEG expands, it will begin to address new topics including bioremediation and sustainable management of aquatic macrophytes in the context of ecosystem services.

  2. Can elevated CO2 modify regeneration from seed banks of floating freshwater marshes subjected to rising sea-level?

    Science.gov (United States)

    Middleton, Beth A.; McKee, Karen L.

    2012-01-01

    Higher atmospheric concentrations of CO2 can offset the negative effects of flooding or salinity on plant species, but previous studies have focused on mature, rather than regenerating vegetation. This study examined how interacting environments of CO2, water regime, and salinity affect seed germination and seedling biomass of floating freshwater marshes in the Mississippi River Delta, which are dominated by C3 grasses, sedges, and forbs. Germination density and seedling growth of the dominant species depended on multifactor interactions of CO2 (385 and 720 μl l-1) with flooding (drained, +8-cm depth, +8-cm depth-gradual) and salinity (0, 6% seawater) levels. Of the three factors tested, salinity was the most important determinant of seedling response patterns. Species richness (total = 19) was insensitive to CO2. Our findings suggest that for freshwater marsh communities, seedling response to CO2 is species-specific and secondary to salinity and flooding effects. Elevated CO2 did not ameliorate flooding or salinity stress. Consequently, climate-related changes in sea level or human-caused alterations in hydrology may override atmospheric CO2 concentrations in driving shifts in this plant community. The results of this study suggest caution in making extrapolations from species-specific responses to community-level predictions without detailed attention to the nuances of multifactor responses.

  3. Latencia y banco de semillas en plantas de la región mediterránea de Chile central Seed bank and dormancy in plants of the Mediterranean region of central Chile

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    JAVIER A. FIGUEROA

    2004-03-01

    un modelo estructural y funcional del banco de semillas para el matorral de Chile central, que debería ser enriquecido con futuras investigacionesSeed banks on Mediterranean regions display characteristics that distinguish them from the seed banks of other regions. A seed bank is the concentration of viable propagules buried in the soil for variable periods of time. Seed banks in the Chilean matorral are chiefly transient and functionally similar to seed banks in other Mediterranean ecosystems not disturbed by fire, except for those of Australia. A transient seed bank is that composed of seeds that cannot survive in the upper levels of the soil for more than 1 year. The density of herb seeds in the Chilean matorral soil is one of the highest among Mediterranean ecosystems anywhere in the world, and a large proportion of these seeds is made up of seeds without dormancy that germinate easily, particularly annual grasses. With respect to the dormancy mechanisms that may be responsible for the behavior of these seeds stored in the transient bank, our analysis revealed the following germination syndromes: (1 species whose seeds must be stratified in cold due to the presence of physiological dormancy (particularly introduced herbs, (2 species whose seeds must be scarified with acids or mechanical means due to the presence of physical dormancy (mainly native woody species and, (3 species that present physiological dormancy and need heat stratification to activate germination (both native and introduced species. These syndromes determine that the timing of germination in central Chile has an autumn and an early spring phase. Besides, there is absence of sporadic germination syndromes for the components of a persistent seed bank. We propose a structural and functional model of the seed bank for the matorral of central Chile that should be enriched with future research

  4. Banco de semillas en ambientes de las sierras de Azul (Buenos Aires, Argentina con distinta intensidad de disturbios Seed bank in environments of the Azul sierras (Buenos Aires, Argentina with different disturbance intensities

    Directory of Open Access Journals (Sweden)

    F. Gianaccini

    2009-12-01

    Full Text Available A fin de evaluar el impacto de la agricultura sobre la flora potencial de pastizales serranos en el Partido de Azul (Buenos Aires, Argentina, se comparó el banco de semillas en los 20 cm superficiales del suelo entre dos sectores adyacentes en las primeras estribaciones serranas. Uno de ellos está sometido a agricultura permanente y el otro conserva un pastizal natural bajo pastoreo y quemas no programados. Este último sector presentó en promedio una densidad de 70.000 sem m-2 contra 36.720 sem m-2 en el primero. La representación de semillas de especies nativas se redujo notablemente en el ambiente agrícola. Stipa caudata con 31360 sem m-2 resultó la especie más abundante en el pastizal. En el ambiente de cultivo, su densidad se redujo a 9940 sem m-2 y fue superada por Chenopodium album con 10560 sem m-2. La similitud en la composición del banco fue de 55% en términos cualitativos y 27% en términos cuantitativos. Estos resultados evidencian que, en el área de estudio, el reemplazo del pastizal natural por agricultura reduce notoriamente las reservas de semillas y modifica la composición cualitativa y cuantitativa del banco con una elevada pérdida en la proporción de especies nativas.In order to evaluate the impact of agriculture on the potential flora of grasslands of the sierras of Azul (Buenos Aires Province, Argentina, the soil seed bank in the top 20 cm from two adjacent areas on the first foothill spurs were compared. One is submitted to continuous agriculture. The other area has grasslands under grazing and non programmed burning. The latter showed a mean density of 70.000 seeds m-2 against a mean density of 36.720 seeds m-2 in the first area. The proportional representation of native species seeds decreased strongly in the agricultural environment. The most abundant species in the grasslands was Stipa caudata (31.360 seeds m-2. In the agricultural environment, its density decreased to 9940 seeds m-2. It was surpassed by

  5. 尾巨桉萌芽林土壤种子库特征分析%Studies on the Characteristics of Soil Seed Banks of Eucalyptus urophylla × E.grandis Sprout Forest

    Institute of Scientific and Technical Information of China (English)

    朱宇林; 唐庆兰; 陆绍锋; 张照远; 刘建

    2012-01-01

    The soil seed bank of Eucalyptus urophyllaxE. Grandis sprout forest and Castanopsis fissa mixed forest were investigated and the characteristics of soil seed bank were studied using the method of seed germination. The results showed that the rule of seed germination was the same in different soil layers. The seeds entered germination peak period from the 7th day, then to slow period followed by end period from the 19th day. The seed density of soil seed banks in E. Urophylla x E. Grandis sprout forest was 7 356 grain/m2, significantly higher than that of control (3 614 grain/m2). A total of 8 species, belonging to 7 families, among which Microstegium ciliatum was the dominant species (accounted for 95.8% of total soil seed bank) was identified. More than 80% of the seeds were stored in the litter layer and 0~5 cm soil layer. The ecological dominance index of soil seed banks in E. Urophylla x E. Grandis sprout forest was obviously higher than that of C. Fissa mixed forest, but the Margalef richness index (R), Shannon-Wiener index (H'), Pielou evenness index (E), Simpson index (D) were lower than that of C. Fissa mixed forest.%对尾巨桉萌芽林和大叶栎杂木林土壤种子库进行了取样调查,采用种子萌发试验研究了不同森林类型的土壤种子库特征.结果表明,各土壤层种子萌发的规律基本一致,大约从第7天开始进入种子萌发高峰期,第19天后进入缓慢萌发期,至最后停止萌发;土壤种子库种子密度尾巨桉萌芽林(7 356粒/m2)显著高于对照大叶栎杂木林(3 614粒/m2).尾巨桉萌芽林土壤种子库共计物种8种,分属于7科,其中以禾本科的刚莠竹为优势种,占土壤种子库总量的95.8%;种子库垂直分布格局显示,80%以上的种子储存在枯枝落叶层和0~5 cm的土壤中.尾巨桉萌芽林土壤种子库具有较高的生态优势度指数,但Margalef丰富度指数、Shannon-Wiener多样性指数、Simpson多样性指数、Pielou均匀度指数及

  6. AMEG: the new SETAC advisory group on aquatic macrophyte ecotoxicology

    OpenAIRE

    Arts, G.; Davies, J.; Dobbs, M.; Ebke, P.; Hanson, M.; Hommen, U.; Knauer, K.; Loutseti, S.; Maltby, L; Mohr, S; Poovey, A.; Poulsen, V.

    2010-01-01

    \\ud Introduction and background\\ud \\ud Primary producers play critical structural and functional roles in aquatic ecosystems; therefore, it is imperative that the potential risks of toxicants to aquatic plants are adequately assessed in the risk assessment of chemicals. The standard required macrophyte test species is the floating (non-sediment-rooted) duckweed Lemna spp. This macrophyte species might not be representative of all floating, rooted, emergent, and submerged macrophyte species be...

  7. AMEG: the new SETAC advisory group on auqatic macrophyte ecotoxicology

    OpenAIRE

    Arts, G.H.P.; Davies, J.; Dobbs, M.; Ebke, P.; Hanson, M.A.

    2010-01-01

    ntroduction and background Primary producers play critical structural and functional roles in aquatic ecosystems; therefore, it is imperative that the potential risks of toxicants to aquatic plants are adequately assessed in the risk assessment of chemicals. The standard required macrophyte test species is the floating (non-sediment-rooted) duckweed Lemna spp. This macrophyte species might not be representative of all floating, rooted, emergent, and submerged macrophyte species because of dif...

  8. AMEG: the new SETAC advisory group on aquatic macrophyte ecotoxicology

    OpenAIRE

    Arts, G.; Davies, J.; Dobbs, M.; Ebke, P.; Hanson, M; Hommen, U.; Knauer, K; Loutseti, S.; Maltby, L.; Mohr, S.; Poovey, A.; Poulsen, V.

    2010-01-01

    \\ud Introduction and background\\ud \\ud Primary producers play critical structural and functional roles in aquatic ecosystems; therefore, it is imperative that the potential risks of toxicants to aquatic plants are adequately assessed in the risk assessment of chemicals. The standard required macrophyte test species is the floating (non-sediment-rooted) duckweed Lemna spp. This macrophyte species might not be representative of all floating, rooted, emergent, and submerged macrophyte species be...

  9. Dissolved organic carbon release by marine macrophytes

    Directory of Open Access Journals (Sweden)

    C. Barrón

    2012-02-01

    Full Text Available Estimates of dissolved organic carbon (DOC release by marine macrophyte communities (seagrass meadows and macroalgal beds were obtained experimentally using in situ benthic chambers. The effect of light availability on DOC release by macrophyte communities was examined in two communities both by comparing net DOC release under light and dark, and by examining the response of net DOC release to longer-term (days experimental shading of the communities. All most 85% of the seagrass communities and almost all of macroalgal communities examined acted as net sources of DOC. There was a weak tendency for higher DOC fluxes under light than under dark conditions in seagrass meadow. There is no relationship between net DOC fluxes and gross primary production (GPP and net community production (NCP, however, this relationship is positive between net DOC fluxes and community respiration. Net DOC fluxes were not affected by shading of a T. testudinum community in Florida for 5 days, however, shading of a mixed seagrass meadow in the Philippines led to a significant reduction on the net DOC release when shading was maintained for 6 days compared to only 2 days of shading. Based on published and unpublished results we also estimate the global net DOC production by marine macrophytes. The estimated global net DOC flux, and hence export, from marine macrophyte is about 0.197 ± 0.015 Pg C yr−1 or 0.212 ± 0.016 Pg C yr−1 depending if net DOC flux by seagrass meadows was estimated by taking into account the low or high global seagrass area, respectively.

  10. Seed dormancy and seed longevity: from genetic variation to gene identification

    NARCIS (Netherlands)

    Nguyen, T.P.

    2014-01-01

    Seed dormancy and seed longevity are the most important survival traits in the soil seed bank. Both traits are induced during seed maturation and evolved to assure seed survival during environmental conditions that cannot support the regular course of life. Seed dormancy is related to the timing of

  11. COMPOSTING AQUATIC MACROPHYTES: SALVINIA AURICULATA AND EICHHORNIA

    Directory of Open Access Journals (Sweden)

    Ana Kleiber Pessoa Borges

    2011-07-01

    Full Text Available High population growth and densities in urban areas and the consumerism present in modern societies have pronounced effect on the generation of organic waste, which may become an environmental problem. Aerobic composting is one of the best known alternatives to treating these wastes. This study aimed to evaluate the applicability of composting as an alternative to the disposal of organic wastes from aquatic macrophytes Eichhornia crassipes and Salvinia auriculata collected in the reservoir UHE Luis Eduardo Magalhães, Tocantins, Brazil and also produce an organic compound from different combinations of macrophytes, prunning residues and organic waste generated by the Campus of Palmas of UFT, TO. The study was conducted in an area of 80m² in unprotected environment at the experimental station of the Campus of Palmas. The experiments were done as three replications in the dry season (from 18.09.2008 to 11.21.2008 and rainy season (from 03.09.2009 to 05.04.2009 and the parameters temperature, pH, total nitrogen and carbon, and organic matter were monitored along with counts of microorganisms. It was possible to produce compost from the combinations of organic wastes within 65 days of composting during the dry season and 55 days in the rainy season. The aquatic macrophytes resulted in a good raw material for composting, since there is not a destination for the excess plant materials removed by the cleaning process of the reservoir.

  12. Review of alien marine macrophytes in Tunisia

    Directory of Open Access Journals (Sweden)

    Y. R. SGHAIER

    2014-06-01

    Full Text Available In the present study, the list of alien marine macrophytes introduced into Tunisia was updated in the light of available data and new observations. A total of 27 alien marine macrophytes have been recorded so far from Tunisia: 18 Rhodophyta, 3 Ochrophyta, 5 Chlorophyta and 1 Magnoliophyta. For each species, the locality (-ies, the year (or period and the source of the first observation in Tunisia are given. The distribution and the status (casual, cryptogenic, established or questionable of species in Tunisia were evaluated and, where appropriate, discussed. Among them, Hypnea cornuta is reported for the first time from Tunisia. Fourteen alien marine macrophytes are established, whereas seven cryptogenic and two casual species require further investigation. Eleven species are considered as invasive or potentially invasive in the Mediterranean Sea: Acrothamnion preissii, Asparagopsis armata, A. taxiformis Indo-Pacific lineage, Hypnea cornuta, Lophocladia lallemandii, Womersleyella setacea, Caulerpa chemnitzia, C. cylindracea, C. taxifolia, Codium fragile subsp. fragile and Halophila stipulacea. Finally, the case of four questionable species is also discussed.

  13. 凉风坳亚热带次生常绿阔叶林土壤种子库和种子雨的特征研究%Primary research on the soil seed bank and seed rain of semi-tropical evergreen-broadleaf forests in LiangFengao of Sichuan

    Institute of Scientific and Technical Information of China (English)

    张丹桔; 宫渊波; 张健

    2012-01-01

    The soil seed banks, seed rain and natural germination are the main constructive parts of the forestry eco-system, which make an indispensable contribution to the vegetation regeneration, succession and diffusion. However, there are little information available for this. In the present study, semi-tropical evergreen-broad leaf forests in Muchuan of Sichuan basin in China were studied on the soil seed bank, seed rain and the germination of the seeds in the soil seed bank under natural conditions before and after the seed' s falling. Furthermore, the factors influencing the soil seed bank were evaluated. The density of the seed banks including 22 leading species arranges 643. 2 ~ 889. 2 ind · m -2 along with time. The soil seed banks in all sample sites were dominated by perennial herbaceous species in terms of species richness and density. Shannon-Wiener index decreased with time, Simpson index showed the reverse trend compared with the Shannon-Wiener index. Pielou index decreased in December, 2004 and then increased in May, 2005. The density of soil seed banks decreased with the depth of the soil layer. It was found that seeds at the litter layers were shorter than that in the superficial soil layer (0-10 cm) , however,most seeds of the arbor trees existed at the litter layers. The species richness and density of soil seed bank in the control plantations were significantly lower than that in studied forests. The seed input each year in the studies forests were 142. 3 ind · m-2 , the output of the valid seeds each year were 268. 9 ind · m-2 . Preying were the main factors resulting in the seed loss. The species similarity between the seed bank and the above ground vegetation were low but that in control plantations were high.%选择四川省沐川县凉风坳亚热带次生常绿阔叶林为研究对象,在2004年5月、2004年12月和2005年5月对其林下土壤种子库、种子雨以及种子天然萌发状况等方面进行系统调查及

  14. 不同封育年限宁夏荒漠草原土壤种子库研究%A Study on soil Seed Bank in Desert Steppe of Different Enclosing Years in Ningxia

    Institute of Scientific and Technical Information of China (English)

    刘华; 蒋齐; 王占军; 潘占兵

    2011-01-01

    针对宁夏天然草原实施禁牧封育的现状,采用种子萌发法对不同封育年限的荒漠草原土壤种子库进行了研究。结果表明:种子萌发主要集中在0-5cm土层中,6-10cm土层种子萌发较少,0-5cm土层中,随封育年限的增加,一年生草本植物逐渐减少,多年生草本植物增加,半灌木或灌木逐渐增加;在垂直分布上,随土层深度的增加单位面积的种子数量减少;土壤种子库的密度随封育时间的增加而增加;在0-5cm土层中,封育使土壤种子库的物种多样性和丰富度明显增加;在0-5cm土层和6-10cm土层中,土壤种子库和地上植被的相似性都较低,在0-5cm土层,随封育年限的增加土壤种子库与地上植被的相似性程度逐渐增加。%According to the present situation of Ningxia natural grassland enclosure,the method of seed germination was used to study soil seed bank in desert steppe of different enclosing years.The result shows: seed germination mainly occurred in 0-5 cm soil,seed germination in 6-10 cm soil was less.In 0-5 cm soil,annual herbs gradually reduce,the perennial herbs increase,half shrubs or shrubs increase gradually with the increase of the enclosing year.In vertical distribution,along with the increase of soil depth,the seeds decreased in the number of unit area.The density of the soil seed bank increased with increase of enclosing year.In 0-5 cm soil,enclosing made the species diversity of the soil seed bank and abundant degree increase.In 0-5 cm and 6-10 cm soil,the soil seed bank and the similarity of above-ground vegetation are low.In 0-5 cm soil layer,with the increasing of enclosing year,soil seed banks and the similarity degree of above-ground vegetation increase gradually.

  15. Advances in seed conservation of wild plant species: a review of recent research

    National Research Council Canada - National Science Library

    Hay, Fiona R; Probert, Robin J

    2013-01-01

    .... Seed banking is now widely used for the ex situ conservation of wild plant species. Many seed banks that conserve wild species broadly follow international genebank guidelines for seed collection, processing, storage, and management...

  16. 内蒙古大兴安岭兴安落叶松土壤种子库研究%Research on Soil Seeds Bank of Larix gmelini Community in Daxing'anling Mountain

    Institute of Scientific and Technical Information of China (English)

    郭鑫; 周海峰; 卢立娜; 贺晓辉; 李维向; 杨宏伟; 王利兵

    2015-01-01

    对内蒙古大兴安岭成熟兴安落叶松纯林的3种不同采伐林分类型(原始林、渐伐林、皆伐林)的土壤种子库储量、质量及其垂直分布(枯枝落叶层、土层0~5cm 和5~10cm)进行了研究,结果表明:不同的采伐林分生长状况,决定了不同的土壤种子储量,渐伐林种子储量最多,皆伐林种子储量最小;从种子库活力程度看,种子整体质量非常差,完整种子中大部分为空粒种子,各林分均为70%左右;土壤种子库中种子集中分布在枯枝落叶层中;各林分林下均有幼苗,表明兴安落叶松纯林土壤种子库种子具有一定的萌发能力。%The density,quality and vertical distribution(litter layer,soil layer 0 ~5 cm and 5 ~10 cm)of soil seed bank of 3 different cutting types(virgin forest、successive cutting forest,clear-cutting forests)on maturation of Larix gmelini pure forest in Daxing'anling Mountains were investigated.The results showed that 1)growth status of cutting forests determines soil seed densities and the successive cutting forest had the largest seed reserves and clear-cutting forest was the minimum,2)the seed qualities were low and al-most 70% seeds were empty in each stand,3)soil seeds intensively distribute in litter layer,4)each stand had understory seedings which indicated that the soil seed bank of Larix gmelini pure forest had cer-tain potential of germination.

  17. Classifying aquatic macrophytes as indicators of eutrophication in European lakes

    NARCIS (Netherlands)

    Penning, W.E.; Mjelde, M.; Dudley, B.; Hellsten, S.; Hanganu, J.; Kolada, A.; van den Berg, Marcel S.; Poikane, S.; Phillips, G.; Willby, N.; Ecke, F.

    2008-01-01

    Aquatic macrophytes are one of the biological quality elements in the Water Framework Directive (WFD) for which status assessments must be defined. We tested two methods to classify macrophyte species and their response to eutrophication pressure: one based on percentiles of occurrence along a phosp

  18. FRACTIONAL BANKING

    OpenAIRE

    Maria Klimikova

    2010-01-01

    Understanding the reasons of the present financial problems lies In understanding the substance of fractional reserve banking. The substance of fractional banking is in lending more money than the bankers have. Banking of partial reserves is an alternative form which links deposit banking and credit banking. Fractional banking is causing many unfavorable economic impacts in the worldwide system, specifically an inflation.

  19. FRACTIONAL BANKING

    OpenAIRE

    Maria Klimikova

    2010-01-01

    Understanding the reasons of the present financial problems lies In understanding the substance of fractional reserve banking. The substance of fractional banking is in lending more money than the bankers have. Banking of partial reserves is an alternative form which links deposit banking and credit banking. Fractional banking is causing many unfavorable economic impacts in the worldwide system, specifically an inflation.

  20. Study on soil seed bank of different alpine degraded grasslands in Nakchu area of Tibet%西藏那曲不同高寒退化草地土壤种子库研究

    Institute of Scientific and Technical Information of China (English)

    王宏辉; 孙磊; 赵玉红; 赵改红; 李龙; 魏学红

    2012-01-01

    【Objective】In order to provide some background knowledge for vegetation restoration,productivity and ecological protection of degraded grasslands in Nakchu area of Tibet,soil feed bank,the number of fermentable seeds,and the ecological characteristics in different degraded grasslands of Nakchu were systematically investigated.【Method】Based on vegetation coverage,plots of four different degradation levels (light degradation,medium degradation,heavy degradation and extremely severe degration)were selected.In four plots which were selected using line transect method,soils with volume of 10 cm×10 cm×10 cm (including litters) were taken as seed bank sample on the first day of each month .The soil was immersed,dissolved and sifted to separate seeds,and the separated seeds were appraised and counted.Then the amount of germinative seeds of soil seed bank was mensured by germination test in the lab.The influence of different mass fractions of GA3(0.10%,0.05% and 0.02%),KNO3(0.20%),H2SO4(60%,70%,80% and 90%)treatment of seed bank on seed germination was analyzed.The importance value of soil bank was calculated through its relative coverage,relative frequency,relative density and relative biomass.The composition and characteristics of plant community of soil bank was also analyzed.【Result】The results showed that the largest number of seeds (530±80.00)grains/m^2 was obtained in the medium degraded meadow in Nakchu,followed by heavy and extremely severe degradation grasslands (250±44.72)grains/m^2,while medium degraded grassland’s seed stock was the least (216±21.34)grains/m^2.Most species in the seed banks were the Rosaceae,Compositae,Gramineae,and so on.Under laboratory conditions,the number of seeds that could germinate was the least in the seed bank of medium degraded grassland(100±0.00)grains/m^2,followed by heavily and extremely severe degraded grasslands,and the largest number of seeds that could germinate was obtained in the medium degraded

  1. Biomass production by freshwater and marine macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    North, W.J.; Gerard, V.A.; Kuwabara, J.S.

    1981-01-01

    Research on aquatic macrophytes as producers of biomass has been undertaken at Woods Hole Oceanographic Institution (WHOI) on the east coast and on the west coast by a group of collaborators in a joint effort known as the Marine Biomass Project. Studies at WHOI have focused on estuarine and coastal situations with some attention recently to freshwater plants. The Marine Farm Project has primarily been concerned with oceanic biomass production. A group at WHOI has undertaken a wide variety of studies concerning aquatic macrophytes including nutrient uptake, growth, yields, and environmental factors affecting yields. Aquatic biomass production systems have been surveyed on a worldwide basis and currently the role of carbon as a potential limiting nutrient in biomass culturing is being examined. The Marine Farm Project is presently attempting to grow giant kelp in offshore waters off southern California. Other work related to aquatic biomass production includes an investigation at the University of California, Berkeley, of microalgae in ponds. This paper will emphasize discussion of the kelp production phases of the Marine Farm Project. Activities by the WHOI are briefly summarized.

  2. Composicion y variabilidad espacialdel banco de semillas de malezas en un area agricolade azul (Argentina Composition and spatial variation of a weed seed bank on an agricultural area in Azul, Argentina

    Directory of Open Access Journals (Sweden)

    Eduardo Requesens

    1999-08-01

    characterize the weed seed bank of such area in a global way. The whole rank of seed density and the relative abundance distribution and spatial design of species were analyzed. The basic information was obtained applying the germination technique to soil samples corresponding to 20 sites on a regional transect of 14 km. The seed density rank for the study area was 1173-44000 seeds/m2, and 33 species were recorded. Digitaria sanguinalis is the predominant species with 43 % of the seed bank, followed by Polygonum aviculare with 15 %. Both species together with Anagallis arvensis and Setaria viridis constitute the 70 % of the seed bank. The spatial distribution of species along the transect showed a variable aggregation degree, recording a significant positive correlation between the contribution to seed bank and the variance/mean ratio. This correlation demostrates that the most abundant species show a greater spatial variation, although different distribution patterns were observed.

  3. Banco de sementes de plantas daninhas em solo cultivado com pastagens de Brachiaria brizantha e Brachiaria humidicola de diferentes idades Weed seed bank in soil cultivated with pasture of Brachiaria brizantha and Brachiaria humidicola of different ages

    Directory of Open Access Journals (Sweden)

    D.S.M. Silva

    2001-08-01

    Full Text Available Estudou-se o banco de sementes do solo de uma pastagem de Brachiaria brizantha com 4 anos de idade e de pastagens de Brachiaria humidicola com 4, 15 e 20 anos de idade, localizadas no nordeste do Estado do Pará. Objetivou-se avaliar a influência da espécie forrageira e da idade da pastagem no tamanho e na composição do banco de sementes de plantas daninhas do solo. Cada pastagem foi dividida em cinco áreas de aproximadamente 500 m², sendo retiradas, de cada área, 10 subamostras de solo na profundidade de 0-10 cm. Cada amostra composta das 10 subamostras de solo foi homogeneizada, identificada, distribuída em bandeja de plástico e levada para germinar em casa de vegetação durante um período de 15 meses. O banco de sementes do solo da pastagem de B. brizantha foi em torno de 10 vezes menor que o da pastagem de B. humidicola de mesma idade. Com relação ao efeito da idade da pastagem, entre as pastagens de B. humidicola, o banco de sementes foi menor naquela de 20 anos de idade (1.247 sementes m-2, não tendo sido detectada diferença significativa entre as pastagens de 15 (11.602 sementes m-2 e 4 (9.486 sementes m-2 anos de idade. As famílias botânicas Cyperaceae, Rubiaceae e Labiateae foram as de maior predominância entre as plantas daninhas infestantes da área, em todos os tratamentos estudados.The objective of this work was to study the soil seed bank of a four-year-old Brachiaria brizantha pasture soil, and in pasture soils of four, 15 and 20 year-old Brachiaria humidicola, in northeastern Pará, Brazil, to evaluate the influence of the forage species and pasture age on weed seed bank size and composition. Each pasture area was divided into five plots of about 500 m², from which 10 soil sub-samples were collected at a depth of 0-10 cm. The soil from each plot was mixed, identified, placed in plastic trays, and put to germinate in a greenhouse during a 15-month period. The seed bank of the four-year-old B. brizantha pasture

  4. An optimisation approach for shallow lake restoration through macrophyte management

    Science.gov (United States)

    Xu, Z. H.; Yin, X. A.; Yang, Z. F.

    2014-06-01

    Lake eutrophication is a serious global environmental issue. Phytoremediation is a promising, cost-effective, and environmentally friendly technology for water quality restoration. However, besides nutrient removal, macrophytes also deeply affect the hydrologic cycle of a lake system through evapotranspiration. Changes in hydrologic cycle caused by macrophytes have a great influence on lake water quality restoration. As a result of the two opposite effects of macrophytes on water quality restoration (i.e. an increase in macrophytes can increase nutrient removal and improve water quality while also increasing evapotranspiration, reducing water volume and consequently decreasing water quality), rational macrophyte control through planting and harvest is very important. In this study, a new approach is proposed to optimise the initial planting area and monthly harvest scheme of macrophytes for water quality restoration. The month-by-month effects of macrophyte management on lake water quality are considered. Baiyangdian Lake serves as a case study, using the common reed. It was found that water quality was closest to Grade III on the Chinese water quality scale when the reed planting area was 123 km2 (40% of the lake surface area) and most reeds would be harvested at the end of June. The optimisation approach proposed in this study will be a useful reference for lake restoration.

  5. An optimisation approach for shallow lake restoration through macrophyte management

    Directory of Open Access Journals (Sweden)

    Z. H. Xu

    2014-01-01

    Full Text Available Lake eutrophication is a serious global environmental issue. Phytoremediation is a promising, cost-effective, and environmentally friendly technology for water quality restoration. However, besides nutrient removal, macrophytes also deeply affect the hydrologic cycle of lake system through evapotranspiration. Changes in hydrologic cycle caused by macrophytes have a great influence on lake water quality restoration. As a result of the two opposite effects of macrophytes on water quality restoration (i.e. an increase in macrophytes can increase nutrient removal and improve water quality while also increasing evapotranspiration, reducing water volume and consequently decreasing water quality, rational macrophyte control through planting and harvest is very important. In this study, a new approach is proposed to optimise the initial planting area and monthly harvest scheme of macrophytes for water quality restoration. The month-by-month effects of macrophyte management on lake water quality are considered. Baiyangdian Lake serves as a case study, using the common reed. It was found that water quality was closest to Grade III on the Chinese water quality scale when the reed planting area was 123 km2 (40% of the lake surface area and most reeds would be harvested at the end of June. The optimisation approach proposed in this study will be a useful reference for lake restoration.

  6. Retail Banking

    Directory of Open Access Journals (Sweden)

    Adam Szafarczyk

    2008-07-01

    Full Text Available The retail banking plays more and more important role in polish banking sector. There are several targets of this article. First of all is retail banking identification, both in Euroland and Poland. The next one trends, especially household deposits and credits and last retail banking in particular banks.

  7. Soil seed bank and aboveground vegetation in Jinshajing Hot-Dry River Valley Hillslope vegetation restoration site%金沙江干热河谷山地植被恢复区土壤种子库和地上植被研究

    Institute of Scientific and Technical Information of China (English)

    罗辉; 王克勤

    2006-01-01

    Soil seed bank plays an important role in the composition of different plant communities and especially in their conservation. Although Soil seed bank, aboveground vegetation and their relationship have been the subject of much recent attention, little is known about the size and species composition of soil seed bank and aboveground vegetation in semi-arid hillslope grasslands and understanding of how these components interact to determine the importance of seed banks to regeneration is limited.We assessed the size and species composition of a soil seed bank and aboveground vegetation in an experiment with 36 vegetation quadrats and 108 soil samples in terrace, slope, gully and grazing land that represent a range of habitats within a hillslope grassland in Jinshajing hot-dry river valley of Yunnan. Terrace, slope and gully represent restored site and grazing land typifies unrestored site. We identified 21 taxa in the seed bank with a median of 7 species/m2 and a median density of 5498 seeds/m2, while in aboveground vegetation, 19 species were observed with a median of 6 species/m2 and a median density of 1088 plants/m2. Both seed bank density and aboveground vegetation density among grazing land, gully, slope and terrace differed significantly. There was an absolutely high proportion of herbaceous species in the seed bank and aboveground vegetation. Gramineae predominated over both seed bank and vegetation. The most frequent seeds and plants were Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) Beauv that had the highest individual number, importance value and biomass. In the seed bank, the seeds of Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) Beauv accounted for 50.68% and for 33.10% of the total seeds respectively. In aboveground vegetation, the individual number of Bothriochloa pertusa (L.) A. Camus accounted for 55.66% of the total and Heteropogon contortus (L.) Beauv accounted for 29.86%. The biomass of Bothriochloa

  8. The Characteristics of Soil Seed Bank and Natural Regeneration of Pinus densiflora Plantation in Zhanggutai Sandyland%章古台沙地赤松人工林土壤种子库及天然更新特征

    Institute of Scientific and Technical Information of China (English)

    刘淑玲; 宋鸽; 刘敏; 陈江燕; 肖巍

    2014-01-01

    研究了章古台沙地赤松人工林土壤种子库及天然更新特征。结果表明:在赤松人工林土壤种子库中,47.47%的种子分布在枯枝落叶层中,种子平均密度可达253粒ûm -2;52.53%的种子分布在0~5 cm 深的土层中,种子平均密度为280粒ûm -2。从种子品质来看,空粒种子占种子总数的40.90%,腐烂种子占39.96%,完整种子占19.14%。赤松天然更新主要为林下更新,更新幼树呈不规则分布,密度为20348~71798株ûhm -2;其次为林隙更新,更新幼树以群团状分布为主,带状分布为辅,密度为7659~14836株ûhm -2;赤松林缘更新的主要条件是有林缘扩展带,林缘更新密度为856~10810株ûhm -2。%This paper studied the characteristics of soil seed bank and natural regeneration of Pinus densiflora planta-tion in Zhanggutai .The result showed that in the seed bank of Pinus densiflora plantation ,47 .47% of the seeds was distributed in the litter layer ,with the average density up to 253 grain ûm - 2 ;52 .53% of the seeds was distributed in soil layer of 0 to 5cm depth ,with average density 280 grain ûm - 2 .From the point of seed quality ,empty seeds ,rot-ten seeds and complete seeds accounted for 40 .90% ,39 .96% and 19 .14% of the total number of seeds separately . The leading natural regeneration of Pinus densiflora was under forest canopy that regenerated saplings were distrib-uted irregularly with the density from 20 348 to 71 798 plant ûhm - 2 .The secondly natural regeneration was in the gap which the distribution of the regenerate saplings was principal in shape of cluster and supplementary in shape of zone ,with the density from 7 659 to 14 836 plant ûhm - 2 .The main condition of natural regeneration in plantation edge was with forest edge extension zone ,with the density from 856 to 10 810 plant ûhm - 2 .

  9. Internet Banking

    Directory of Open Access Journals (Sweden)

    Felician ALECU

    2006-01-01

    Full Text Available Internet Banking (known also as online banking allows performing transactions and payments over the internet through a bank's secure website. This can be very useful, especially for banking outside bank hours (which tend to be very short and banking from anywhere where internet access is available. In most cases a web browser such as Internet Explorer or Mozilla Firefox is utilized and any normal internet connection is suitable. No special software or hardware is usually needed.

  10. Effect of paclobutrazol on three different aquatic macrophytes under ...

    African Journals Online (AJOL)

    admin

    2013-09-25

    Sep 25, 2013 ... macrophytes under in vitro monoculture or polyculture conditions ... provide many beneficial ecological services, but they could also be problematic .... addition, it was also important to remove all the leaves from the explants.

  11. 中国对英国邱园的千年种子库计划的贡献%Chinese Contribution to the Millennium Seed Bank Project Launched by the Royal Botanic Gardens, Kew

    Institute of Scientific and Technical Information of China (English)

    芦笛

    2013-01-01

    As one of the largest botanic gardens in the world, the Royal Botanic Gardens, Kew launched the Millennium Seed Bank project in 2000, aiming to conserve the seeds of 10% of the seed­bearing flora in order to cope with the unpredictable deterioration in the ecological environment in the future. This project has gained support from 123 partners distributed in 54 countries since then, and the Bank has successfully conserved the seeds of over 24 000 species. China joined the project in 2004 and had contributed 247 accessions, consisting of 232 species which distribute in 52 families and 139 genera. Kunming Institute of Botany, Chinese Academy of Sciences contributed most of the species which are collected in Yunnan and are unique to China. In terms of the germination, the quality of the seed is quite good.%  作为世界最大的植物园之一,英国邱区的皇家植物园(简称“邱园”)于2000年发起了“千年种子库”计划,旨在保存全世界10%的种子植物的种子,以应对未来不可预测的生态环境恶化。该计划自实施以来得到了来自54个国家123个合作伙伴的支持,种子库截止2010年已经保存了世界各地2万4千多种植物的种子。中国于2004年正式参加该计划,截止2012年12月31日已为种子库贡献了52科139属232种,共247个登记数的种子,其中大多是中国特有的种,这些种子绝大部分采自云南。从发芽率来看,种子质量很高。

  12. Oligochaeta (Annelida: Clitellata) associated to aquatic macrophytes in Brazil

    OpenAIRE

    Nathalie Aparecida de Oliveira Sanches; Marina Gulo Alcorinte; Lucas Henrique Sahm; Guilherme Rossi Gorni; Maria Lúcia Ribeiro

    2016-01-01

    Oligochaeta are still characterized as a poorly studied group among the aquatic macroinvertebrates and few studies about their ecology were conducted in Brazil. Thus, our study aimed to provide an overview of the association between Oligochaeta and macrophytes, in Brazilian continental aquatic environments, by means of a literature review along with an inventory of species associated to aquatic macrophytes on marginal lagoons in the reservoir Ribeirão das Anhumas (Américo Brasiliense, São Pau...

  13. Aquatic macrophyte diversity of the Pantanal wetland and upper basin

    OpenAIRE

    VJ. Pott; Pott, A; LCP. Lima; SN. Moreira; AKM Oliveira

    2011-01-01

    This is a short review of the state of the art concerning diversity of aquatic macrophytes and the main aquatic vegetation types in the Brazilian Pantanal wetland and upper watershed. There are ca. 280 species of aquatic macrophytes on the Pantanal floodplain, with scarce endemism. On the upper watershed, Cerrado wetlands (veredas) and limestone springs have a distinct flora from the Pantanal, with twice the species richness. As a representative case of aquatic habitats influenced by river fl...

  14. Soil Seed Bank Characteristics Preliminary Comparison between Plantation and Natural Forest of Betula alnoides%西南桦人工林与天然林土壤种子库特征初步比较

    Institute of Scientific and Technical Information of China (English)

    陈勇; 刘海姣; 张劲峰; 耿云芬

    2013-01-01

    以西南桦人工林与天然林的土壤种子库为研究对象,采用室内萌发法对云南热区的西南桦人工林与天然林下0 ~10 cm深度的土壤种子库的种子储量及其垂直分布进行了研究.研究结果表明:①西南桦人工林有活力种子储量为2 027粒/m2,天然林有活力种子储量为3 043粒/m2;②西南桦人工林土壤种子库由21科38属的42种植物组成,其中乔木4种,占全部种类的0.69%;灌木16种,占7.70%;多年生草本10种,占14.90%;1 a生草本9种,占73.36%;藤本3种,占3.35%.西南桦天然林土壤种子库由24科43属的49种植物组成,其中乔木6种,占全部种类的10.56%;灌木15种,占18.31%;多年生草本14种,占4.38%;1 a生草本10种,占65.06%;藤本4种,占1.69%;③乔木、灌木的植物数量占总数的比例为天然林>人工林,而草本和藤本为天然林<人工林;④西南桦人工林与天然林土壤种子库有活力种子密度自上而下都呈现下降趋势,0~5 cm种子数量较5 ~ 10 cm多.%Taking soil seed bank of Betula alnoides plantation and Betula alnoides natural forest as the object, seeds storage and vertical distribution of soil seed bank under depth of 0 ~ 10cm were studied in Yunnan hot zone by using indoor germination method. The results showed that; (1)Vigor seed reserves of Betula alnoides plantation was 2027 seeds/ m2, and natural forest was 3043 seeds/ m2; (2) Soil seed bank of Betula alnoides plantation was consisted of 42 plant species belonging to 21 family and 38 genus, including 4 kinds of Arbor species, accounting for 0. 69% of all species; 16 kinds of shrubs, accounting for 7. 70% ; 10 kinds of perennial herbs, accounting for 14. 90% ; 9 kinds of annual herb, accounting for 73. 36% ; 3 kinds of Fujimoto, accounting for 3. 35% . Soil bank of Betula alnoides natural forest was consisted of 49 plant species belonging to 24 family and 43 genus, including 6 kinds of trees, accounting for

  15. Oligochaeta (Annelida: Clitellata associated to aquatic macrophytes in Brazil

    Directory of Open Access Journals (Sweden)

    Nathalie Aparecida de Oliveira Sanches

    2016-09-01

    Full Text Available Oligochaeta are still characterized as a poorly studied group among the aquatic macroinvertebrates and few studies about their ecology were conducted in Brazil. Thus, our study aimed to provide an overview of the association between Oligochaeta and macrophytes, in Brazilian continental aquatic environments, by means of a literature review along with an inventory of species associated to aquatic macrophytes on marginal lagoons in the reservoir Ribeirão das Anhumas (Américo Brasiliense, São Paulo, Brazil. In the review, we analyzed 10 articles, where we obtained data on 41 species. We also sampled 5 macrophyte genera, Egeria, Salvinia, Utricularia, Eleocharis, and Ceratophyllum, in August and December 2012 and in March and April 2013, in the reservoir Ribeirão das Anhumas. We registered 21 Oligochaeta species associated to these macrophytes. With the data obtained in the review along with the inventory of the reservoir Ribeirão das Anhumas, we found a total of 41 species associated to aquatic macrophytes, with a higher richness of the Naididae family (93.33%, followed by Opistocystidae (4.44%, and Alluroididae (2.22%. Our study inventoried about 48% of the Oligochaeta diversity registered in continental ecosystems in Brazil, thus highlighting the significance of macrophytes as a resource for these invertebrates, mainly for the Naididae family.

  16. Characterization of the Weed Seed Bank in Zero and Conventional Tillage in Central Chile Caracterización del Banco de Semillas de Malezas en Labranza Cero y Convencional en Chile Central

    Directory of Open Access Journals (Sweden)

    Rosa Peralta Caroca

    2011-03-01

    Full Text Available We studied the abundance, species composition, and depth distribution of the weed seed bank under no-tillage (NT and conventional tillage (CT at two sites, A and B. Soil samples were taken at three soil depths (0-2, 2-5, and 5-15 cm. Germinated, dormant, and total seeds were counted. The total number of seeds was higher (p ≤ 0.05 under CT treatment at the two sites (CTA = 5175 seeds m-2, NTA = 3250 seeds m-2, CTB = 33770 m-2, and NTB = 22437 seeds m-2. The number of viable, dormant, and germinated seeds was also higher (p ≤ 0.05 in CT at the two sites. The percentage of viable seeds was low with 37% (CTA, 34% (CTB, 21% (NTA, and 8% (NTB. Viable seeds of Chenopodium album L. (CHEAL dominated in the two trials with 67% (CTA, 20% (NTA, 96% (CTB, and 77% (NTB. In a principal component analysis, PC1 separated viable seeds of weed species according to tillage and PC2 separated weed species according to sites. Poa annua L. was the most important species associated with NT followed by Cichorium intybus L., and Sonchus while Euphorbia helioscopia L. and Echinochloa crus-galli (L. P. Beauv. were associated with CT.Se estudió la abundancia, composición de especies y distribución en profundidad del banco de semilla de maleza en labranza convencional (CT y cero labranza (NT en dos sitios, A y B. Se tomaron muestras a tres profundidades de suelo (0-2, 2-5 y 5-15 cm. Se contaron semillas germinadas, dormantes y totales. La cantidad total de semillas fue significativamente mayor (p ≤ 0,05 para ambos sitios (CTA = 5175 semillas m-2, NTA = 3250 semillas m-2, CTB = 33770 semillas m-2 y NTB = 22437 semillas m-2. La cantidad de semillas viables, dormantes y germinadas fue significativamente mayor (p ≤ 0.05 para ambos ensayos en CT que en NT. La mayor proporción de las semillas viables correspondió a germinadas. Se observó un bajo porcentaje de semillas viables 37% (CTA, 34% (CTB, 21% (NTA and 8% (NTB. Las semillas viables de Chenopodium album L. (CHEAL

  17. Macrophytes shape trophic niche variation among generalist fishes

    Science.gov (United States)

    Vejřík, Lukáš; Šmejkal, Marek; Čech, Martin; Sajdlová, Zuzana; Frouzová, Jaroslava; Kiljunen, Mikko; Peterka, Jiří

    2017-01-01

    Generalist species commonly have a fundamental role in ecosystems as they can integrate spatially distinct habitats and food-web compartments, as well as control the composition, abundance and behavior of organisms at different trophic levels. Generalist populations typically consist of specialized individuals, but the potential for and hence degree of individual niche variation can be largely determined by habitat complexity. We compared individual niche variation within three generalist fishes between two comparable lakes in the Czech Republic differing in macrophyte cover, i.e. macrophyte-rich Milada and macrophyte-poor Most. We tested the hypothesis that large individual niche variation among generalist fishes is facilitated by the presence of macrophytes, which provides niches and predation shelter for fish and their prey items. Based on results from stable nitrogen (δ15N) and carbon (δ13C) isotopic mixing models, perch (Perca fluviatilis L.) and rudd (Scardinius erythrophthalmus (L.)) showed larger individual variation (i.e., variance) in trophic position in Milada as compared to Most, whereas no significant between-lake differences were observed for roach (Rutilus rutilus (L.)). Contrary to our hypothesis, all the three species showed significantly lower individual variation in the relative reliance on littoral food resources in Milada than in Most. Rudd relied significantly more whereas perch and roach relied less on littoral food resources in Milada than in Most, likely due to prevalent herbivory by rudd and prevalent zooplanktivory by perch and roach in the macrophyte-rich Milada as compared to macrophyte-poor Most. Our study demonstrates how the succession of macrophyte vegetation, via its effects on the physical and biological complexity of the littoral zone and on the availability of small prey fish and zooplankton, can strongly influence individual niche variation among generalist fishes with different ontogenetic trajectories, and hence the overall

  18. Investigation of Darwin’s naturalization hypothesis in invaded macrophyte communities

    Science.gov (United States)

    Although native macrophytes are beneficial in aquatic ecosystems, invasive macrophytes can cause significant ecological and economic harm. Numerous studies have attributed invasiveness to species’ characteristics, whereas others attribute invasion to biotic and abiotic characteristics of the invaded...

  19. Assessment of the Potential Biological Activity of Low Molecular Weight Metabolites of Freshwater Macrophytes with QSAR

    National Research Council Canada - National Science Library

    Kurashov, Evgeny A; Fedorova, Elena V; Krylova, Julia V; Mitrukova, Galina G

    2016-01-01

    ... (Prediction of Activity Spectra for Substances) for the major components of three macrophytes widespread in the Holarctic species of freshwater, emergent macrophyte with floating leaves, Nuphar lutea (L.) Sm...

  20. Reproductive Allocation in Three Macrophyte Species from Different Lakes with Variable Eutrophic Conditions

    Science.gov (United States)

    Wan, Tao; Han, Qingxiang; Xian, Ling; Cao, Yu; Andrew, Apudo A.; Pan, Xiaojie; Li, Wei; Liu, Fan

    2016-01-01

    Reproductive allocation is a key process in the plant life cycle and aquatic plants exhibit great diversity in their reproductive systems. In the present study, we conduct a field investigation of three aquatic macrophytes: Stuckenia pectinata, Myriophyllum spicatum, and Potamogeton perfoliatus. Our results showed that widespread species, including S. pectinata and M. spicatum had greater plasticity in their allocation patterns in the form of increased sexual and asexual reproduction, and greater potential to set seeds and increase fitness in more eutrophic environments. P. perfoliatus also exhibited a capacity to adopt varied sexual reproductive strategies such as setting more offspring for the future, although only in clear conditions with low nutrient levels. Our results establish strategies and mechanisms of some species for tolerating and surviving in varied eutrophic lake conditions. PMID:27806122

  1. Effect of removal of free-floating macrophytes on zooplankton habitat in shallow wetland

    OpenAIRE

    Choi Jong-Yun; Jeong Kwang-Seuk; La Geung-Hwan; Joo Gea-Jae

    2014-01-01

    Submerged macrophytes improve the structural heterogeneity of microhabitats in aquatic ecosystems, often providing an important habitat for zooplankton. However, excessive development of free-floating macrophytes on the water surface can reduce the biomass of submerged macrophytes and result in a relatively simple habitat structure. We hypothesized that controlling the development of free-floating macrophytes would result in a more complex habitat structure by promoting the development of sub...

  2. Soil seed banks in the Pinus bungeana forestland of the Huanglong Mountains on the Loess Plateau%黄土高原地区黄龙山白皮松林地土壤种子库研究

    Institute of Scientific and Technical Information of China (English)

    秦廷松; 李登武; 吕振江; 陈亚莉

    2011-01-01

    采用萌发法和分粒结合的方法对陕西省黄龙山地区白皮松Pinus bungeana林地土壤种子库的物种组成、垂直分布和多样性等群落生态因子进行了对比研究.结果表明:黄龙山地区白皮松林地土壤种子库萌发期和落种期2个不同物候期的物种结构相似,全年土壤种子库共有物种44种,隶属34个属26个科;包括乔木、灌木、草本和藤本4种类型.将土壤种子库分为0~5,5~10,10~15 cm等3个层次,不同土壤层次间种子个体数和物种数差异极显著(P<0.01),均呈现上层(0~5 cm)>中层(5~10 cm)>下层(10~15 cm)的趋势.研究的12个样地土壤种子库的Margalef丰富度指数、Shannon-Wiener多样性指数和Pielou均匀度指数平均值分别为3.87,3.63和1.15,受人为活动影响强烈的样地多样性指数明显低于远离耕作区的样地.在整个的演替更新过程中,白皮松的更新能力强于其他乔木树种,主要表现在幼苗幼树和种子数占绝对优势,草本植物的种子数量和物种数都高于木本植物,在乔木树种更新能力弱的样地个别草本物种迅猛繁殖,导致物种多样性和均匀度降低.%This study aims to understand the composition structure and function characteristics of the soil seed banks in the Pinus bungeana forestland of the Huanglong Mountain area. A comparative study in species composition , vertical distribution, diversity, and other community ecological factors of soil seed banks in Pinus bungeana forests, which was undertaken by adopting the germination and grain combining methods. Treatments included three layers; 0-5, 5-10, and 10-15 cm layers and analysis included three indexes; the Margalef abundance, Shannon-Wiener diversity, and Pielou evenness degree. Regeneration and succession for four structural types namely, trees, shrubs, herbs, and lianas were also compared(12 plots, 3 replications). The results indicated that the germination period was identical to the seed

  3. 天山中部天山云杉林土壤种子库海拔梯度分布格局%Distribution Patterns of Soil Seed Bank of Picea Schrenkiana Forests along the Altitudinal Gradient in the Central Section of Tianshan Mountains, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    李华东; 潘存德; 张国林; 王兵

    2012-01-01

    [Objective] Through the sampling and analysis on Picea schrenkiana forests soil seed bank at an altitude from 1,450 m to 2,750 m on the central northern slope of Tianshan Mountains, the research aimed -at in - depth understanding of the distribution pattern of the soil seed bank along the altitudinal gradient, thus it can provide scientific basis for forest ecosystem conservation, restoration and sustainable management in Tianshan Mountains. [ Method ] Combined with soil seed bank sampling and laboratory germination, in order to identify the species composition of soil seed bank and seed quantity. [Result] Through the germination of P. schrenkiana forests soil seed bank, we identified 49 species of seed plants, belonging to 23 families and 38 genera. With the altitude rising, the number of species composition of P. schrenkiana forests soil seed bank shows a declining trend in the fluctuation as a whole. At the altitude of 2,000 m (1,950 -2,050 m) species reached the e maximum, that is 30 species. The common species first increased and then decreased and finally got stabilized between neighboring altitudinal gradients. The seed density of P. schrenkiana forests soil seed bank presented single peak distribution pattern, the maximum density (1 813. 8 ?154. 0 seeds/m2 ) appearing at the altitude of 2,000 m (1,950 -2,050 m). P. schrenkiana seed density in the soil seed bank also presented single peak distribution pattern, the maximum density (190.0 ?16.8 seeds/m2) appearing at the altitude of 1,800 m (1,750 - 1,850 m). [ Conclusion] With the altitude rising, the number of species composition of P. schrenkiana forests soil seed bank shows a declining trend in the fluctuation as a whole. Both of the seed density in P. schrenkiana forests soil seed bank and P. schrenkiana seed density in the soil seed bank presented single peak distribution pattern with the altitude rising. However, they do not share synchronization on the vertical distribution of the altitude.%[目的]

  4. Implementation and implications of macrophyte reconfiguration in hydraulic river modeling

    Science.gov (United States)

    Verschoren, Veerle; Schoelynck, Jonas; Buis, Kerst; Meire, Dieter; Bal, Kris; Meire, Patrick; Temmerman, Stijn

    2014-05-01

    In lowland rivers, abundant macrophyte growth can often be observed. The aquatic vegetation has an impact on the flow by creating friction which results in increased water levels and decreased flow velocities. At the same time submerged macrophytes are susceptible to hydrodynamic forces of the water. Their morphology is therefore often flexible and streamlined so that it enables reconfiguration (i.e. bending of macrophytes with water flow) and decreases potential damage at high flow velocities. Knowledge of these mutual interactions is crucial in order to model water flow in vegetated rivers. A correct estimation of flow velocity and water height is indispensable for the calculation of hydraulic, ecological and geomorphological parameters. The total resistance to water flow in a river can be described by a Manning coefficient. This value is influenced by river characteristics as well as by the presence of macrophytes. In this study a simple method is developed to quantify the resistance created by macrophytes after reconfiguration of their canopy. In order to achieve this we derive model formulations and plant parameters for three different macrophyte species and compare model simulation with measured flow velocity data for two case studies. Furthermore, the effect of macrophyte reconfiguration is investigated by modeling the same case studies with and without the implementation of macrophyte reconfiguration. It was found that the local resistance created by the vegetation was overestimated when reconfiguration was not considered. This resulted in an overestimation of stream velocity adjacent to the vegetation and an underestimation of the stream velocity within and behind the vegetation. Another effect was a higher water level gradient and consequently a higher Manning coefficient in the scenario without reconfiguration compared to the scenario with reconfiguration. Reconfiguration had also an influence on ecological and geomorphological parameters. It was found

  5. Banking Bank Charge Debates Continue

    Institute of Scientific and Technical Information of China (English)

    WANG PEI

    2006-01-01

    @@ The saying, "There's no such thing as a free lunch" is one that can be applied to the charges increasingly being imposed on savers by Chinese banks.Ranging from managementfees for small deposit accounts to charges for withdrawals of large amounts of cash, from ATM cross-bank withdrawal charges to annual fees for bank payment cards, charges by banks are becoming a unstoppable trend. But it is not a trend the general public is so keen to accept.

  6. Effect of removal of free-floating macrophytes on zooplankton habitat in shallow wetland

    Directory of Open Access Journals (Sweden)

    Choi Jong-Yun

    2014-01-01

    Full Text Available Submerged macrophytes improve the structural heterogeneity of microhabitats in aquatic ecosystems, often providing an important habitat for zooplankton. However, excessive development of free-floating macrophytes on the water surface can reduce the biomass of submerged macrophytes and result in a relatively simple habitat structure. We hypothesized that controlling the development of free-floating macrophytes would result in a more complex habitat structure by promoting the development of submerged macrophytes. After applying three experimental treatments (NR, no removal; IR, intermediate removal; CR, complete removal of free-floating macrophytes, we found that CR of free-floating macrophytes improved the growth and development of submerged macrophytes and supported a large zooplankton assemblage. However, the largest zooplankton assemblage (in terms of abundance and diversity was recorded after the IR treatment. Although submerged macrophytes were abundant in the CR treatment, the number, abundance, and density of zooplankton species were much lower than those in the IR treatment. Preferential selection of different macrophyte types by zooplankton presumably led to variation in plant utilization of niches, and the simultaneous presence of different macrophyte life forms created a complex microhabitat structure that induced high species diversity and zooplankton density.

  7. Species Structure Characteristics of Soil Seed Bank of Pinus yunnanensis Forest Invaded by Eupatorium adenophorum%紫茎泽兰入侵云南松林土壤种子库物种结构特征

    Institute of Scientific and Technical Information of China (English)

    曹子林; 王晓丽; 李根前; 许加胜

    2016-01-01

    Pinus yunnanensis forests were generally disturbed by invasive species Eupatorium adenopho⁃rum,soil seed bank sampling and germination experiments were conducted to study the soil seed bank species structure of P.yunnanensis forest invaded by E.adenophorum.The results showed that invasion of E.adenopho⁃rum had strong influence on quantitative characteristics of seed bank in different layers.The frequency of E.ad⁃enophorum in the litter layer,0-2 cm,2-5 cm,5-10 cm was 100%. The seed storage,relative density,relative frequency and important value of E.adenophorum amount maximum,and it was a dominant species in correspond⁃ing layers.But the influence descended gradually along with the litter layer,0-2 cm,2-5 cm to 5-10 cm. The seed storage in the litter layer,0-2 cm was 1 523.4,2 301.6 ind/m2 ,respectively,but descended to 579.7 ind/m2 in 5-10 cm.The relative density in the litter layer was 97.21%,but descended to 52.33% in 5-10 cm.The rela⁃tive frequency in the litter layer was 42.11%,but descended to 11.59% in 5-10 cm.The important value in the litter layer was 139.31%,but descended to 63.92% in 5-10 cm.The species number and species richness in⁃dex in the litter layer were the lowest,but the indice tended to increase with the increase of soil depth.The eco⁃logical dominance index was the highest in the litter layer,but was the lowest in 5-10 cm. The changing rule was opposite to the former.The Shannon⁃wiener index and evenness index in 2-5 cm were the highest,the in⁃dice descended in the sequence of 5-10 cm,0-2 cm and the litter layer.Herb speices were the absolutely dom⁃inant life form in corresponding layers,accounting for 93.48%-98.90% of the total storage in the soil seed bank.The individual number and species number of wood speices were less,accounting for 1.10%-6.52% of the total storage.%云南松林普遍受到外来入侵种紫茎泽兰的干扰,采用土壤种子库取样和萌发实验相结合的方法,探讨紫茎泽兰入侵

  8. Is shadow banking really banking?

    OpenAIRE

    Bryan J. Noeth; Rajdeep Sengupta

    2011-01-01

    To those who don't know, the term "shadow banking" probably has a negative connotation. This primer draws parallels between what has been termed the shadow banking sector and the traditional banking sector—showing that they are similar in many ways.

  9. Bank regulation and banking stability

    NARCIS (Netherlands)

    Boot, A.; Thakor, A.V.

    2014-01-01

    This note discusses some issues in bank closure policy from a financial stability standpoint and how these issues have evolved since we first raised the question of how a reputation-driven divergence of interests between bank regulators and taxpayers may distort bank closure policy in our 1993 paper

  10. Chemical warfare in freshwater. Allelpathic effects of macrophytes on phytoplankton

    NARCIS (Netherlands)

    Mulderij, G.

    2006-01-01

    Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field expe

  11. AMEG: the new SETAC advisory group on auqatic macrophyte ecotoxicology

    NARCIS (Netherlands)

    Arts, G.H.P.; Davies, J.; Dobbs, M.; Ebke, P.; Hanson, M.A.

    2010-01-01

    ntroduction and background Primary producers play critical structural and functional roles in aquatic ecosystems; therefore, it is imperative that the potential risks of toxicants to aquatic plants are adequately assessed in the risk assessment of chemicals. The standard required macrophyte test

  12. AMEG: the new SETAC advisory group on auqatic macrophyte ecotoxicology

    NARCIS (Netherlands)

    Arts, G.H.P.; Davies, J.; Dobbs, M.; Ebke, P.; Hanson, M.A.

    2010-01-01

    ntroduction and background Primary producers play critical structural and functional roles in aquatic ecosystems; therefore, it is imperative that the potential risks of toxicants to aquatic plants are adequately assessed in the risk assessment of chemicals. The standard required macrophyte test spe

  13. Experiments on growth interactions between two invasive macrophyte species

    NARCIS (Netherlands)

    Barrat-Segretain, M-H.; Elger, A.F.

    2004-01-01

    The success of invasive species has been attributed to the ability to displace other species by direct competition. We studied growth and possible competition between the two macrophyte species Elodea nuttallii and E. canadensis, because the former has been observed to replace the latter in the

  14. Macrophytes in estuarine gradients: flow through flexible vegetation

    NARCIS (Netherlands)

    Dijkstra, J.T.

    2012-01-01

    Aquatic plants –or macrophytes- are an important part of coastal, estuarine and freshwater ecosystems worldwide, both from an ecological and an engineering viewpoint. Their meadows provide a wide range of ecosystem services: forming a physical protection of the shoreline, enhancing water quality and

  15. African Journal of Science and Technology (AJST) MACROPHYTES ...

    African Journals Online (AJOL)

    opiyo

    MACROPHYTES ET GROUPEMENTS VÉGÉTAUX AQUATIQUES. ET AMPHIBIES DE LA ... plaine d'inondation indique que le marnage demeure important et la salinité des terres reste encore élevée. ..... The Journal of Ecology, vol. 54, n° 3 ...

  16. Macrophyte presence and growth form influence macroinvertebrate community structure

    NARCIS (Netherlands)

    Walker, P.D.; Wijnhoven, S.; van der Velde, G.

    2013-01-01

    Multivariate analysis demonstrated that macroinvertebrate assemblages of macrophyte-dominated sub-habitats within a small eutrophic pond differed markedly from those of Bottom substrate and Open water habitats. Certain habitats (e.g. Nymphaea and Phragmites) appeared to be quite similar in their

  17. Herbivory on freshwater and marine macrophytes : A review and perspective

    NARCIS (Netherlands)

    Bakker, Elisabeth S.; Wood, Kevin A.; Pages, Jordi F.; Veen, G. F. (Ciska); Christianen, Marjolijn J. A.; Santamaria, Luis; Nolet, Bart A.; Hilt, Sabine

    2016-01-01

    Until the 1990s, herbivory on aquatic vascular plants was considered to be of minor importance, and the predominant view was that freshwater and marine macrophytes did not take part in the food web: their primary fate was the detritivorous pathway. In the last 25 years, a substantial body of

  18. Herbivory on freshwater and marine macrophytes : A review and perspective

    NARCIS (Netherlands)

    Bakker, Elisabeth S.; Wood, Kevin A.; Pages, Jordi F.; Veen, G. F. (Ciska); Christianen, Marjolijn J. A.; Santamaria, Luis; Nolet, Bart A.; Hilt, Sabine

    2016-01-01

    Until the 1990s, herbivory on aquatic vascular plants was considered to be of minor importance, and the predominant view was that freshwater and marine macrophytes did not take part in the food web: their primary fate was the detritivorous pathway. In the last 25 years, a substantial body of evidenc

  19. Species pool versus site limitations of macrophytes in urban waters

    DEFF Research Database (Denmark)

    Vermonden, K.; Leuven, R.S.E.W.; van der Velde, G.

    2010-01-01

    Biodiversity in urban areas is affected by a multitude of stressors. In addition to physico-chemical stress factors, the native regional species pool can be greatly reduced in highly urbanized landscapes due to area loss and fragmentation. In this study, we investigated how macrophyte composition...

  20. Chemical warfare in freshwater. Allelpathic effects of macrophytes on phytoplankton

    NARCIS (Netherlands)

    Mulderij, G.

    2006-01-01

    Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field

  1. Banks Sparkle

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    There is no doubt that China’s banking system is a calm port in the global financial storm. Moreover, a great regulatory firewall and an easing monetary environment have enabled Chinese banks to increase lending and help shrug off the economic downturn. Yi Xianrong, a researcher at the Institute of Finance and Banking under the Chinese Academy of Social Sciences, discussed this topic in a recent article in the Shanghai Securities Journal. Edited excerpts follow:

  2. Seed storage at elevated partial pressure of oxygen, a fast method for analysing seed ageing under dry conditions

    NARCIS (Netherlands)

    Groot, S.P.C.; Surki, A.A.; Vos, de R.C.H.; Kodde, J.

    2012-01-01

    Background and Aims Despite differences in physiology between dry and relative moist seeds, seed ageing tests most often use a temperature and seed moisture level that are higher than during dry storage used in commercial practice and gene banks. This study aimed to test whether seed ageing under

  3. On the efficiency analysis of wasteland soil vegetation recovery based on the Soil Seed Bank%基于土壤种子库的沙荒地植被恢复研究

    Institute of Scientific and Technical Information of China (English)

    陈颖; 郭耸松; 刘海翔; 李玉灵; 李继泉

    2014-01-01

    The Soil Seed Bank of adjacent provenance to the degraded wasteland was used to analyses the efficiency of 2 different treatments by new soil + SAP and new soil on the soil amelioration and vegetation restoration of the degraded sandy wasteland ,so as to provide theoretical basis for vegetation restoration and reconstruction technology . The results showed :① Seed bank species were composed of the dominative perennial herbaceous plants , with a majority of dicotyledons ,but without trees and shrubs seeds found .The seed density was 1 524 .64 seed/m2 in the provenance higher than 843 .76 seed/m2 in the sandy wasteland .② The content of soil organic matter ,Total N ,Total P ,Total K ,alkali‐hydrolyzable N ,a‐vailable P ,and available K in the 0~10 cm soil layer indicated new soil + SAP>new soil>sandy wasteland (CK) ,while in 10~20 cm and 20~40 cm soil layers ,there was no signifi‐cant difference in the three plots .③The ground and underground biomass treated by both new soil and new soil + SAP proved to be far higher than that of the sandy wasteland ,with new soil biomass of 937 .80g/m2 ,which was 3 .27 times as high as the sandy wasteland bio‐mass of 287 .11 g/m2 .But the shoot ratio of the 3 plots was 1 .85 of sandy wasteland > 1 .69 of new soil > 1 .04 of new soil + SAP ,which explains droughty soil promoted the root growth .④ The species diversity of herbaceous plants in different treatments showed Mar‐galef richness index and Simpson diversity index were both new soil + SAP> new soil >sandy w asteland .T here w as no difference in Pielou evenness index and Shannon‐Wiener di‐versity index between the treatments of new soil and new soil + SAP ,but they were still higher than that of sandy wasteland .%通过借用退化沙荒地附近种源地土壤种子库的客土方式,分析客土+保水剂、客土2种不同措施对退化沙荒地土壤改良和植被恢复的作用,为沙荒地植被自然恢复与重建技

  4. Temporal and habitat distribution of macrophytes in lowland eutrophic reservoir Gruža in Serbia

    OpenAIRE

    Topuzović, Marina; Pavlović, Dragana; Ostojić, Aleksandar

    2016-01-01

    Background and Purpose: The research in this paper are based on the study of the distribution in time and space of macrophytes along the different parts of shoreline of Gruža Reservoir and emphasize the importance of establishing relations between distribution, diversity and mass of macrophytes and the ecological conditions of the environment. Development diversity of macrophytes needs to be constantly monitored and their regulation is necessary for Reservoir conservation, especially because...

  5. Temporal and spatial distribution of macrophytes in the Gruža Reservoir (Serbia)

    OpenAIRE

    Topuzović Marina; Pavlović Dragana; Ostojić A.

    2009-01-01

    A survey of aquatic macrophytes in the Gruža Reservoir (Serbia) was conducted during the period 2007-2008. Detailed data on the actual condition of macrophytes were established and compared between four parts of the reservoir. The distributions of most aquatic macrophytes of the Gruža Reservoir are heterogeneous, with different values of the MMT and MMO indices and low values of the distribution ratio. Quantitative analysis indicates that the greatest diversity and abundance of species can be...

  6. Response of littoral macrophytes to water level fluctuations in a storage reservoir

    OpenAIRE

    Krolová M.; Čížková H.; Hejzlar J.; Poláková S.

    2013-01-01

    Lakes and reservoirs that are used for water supply and/or flow regulations have usually poorly developed littoral macrophyte communities, which impairs ecological potential in terms of the EU Water Framework Directive. The aim of our study was to reveal controlling factors for the growth of littoral macrophytes in a storage reservoir with fluctuating water level (Lipno Reservoir, Czech Republic). Macrophytes occurred in this reservoir only in the eulittoral zone i.e., the shoreline region be...

  7. Macrophytes: Limitations of Using Them to Assess Reservoir Status According to the Water Framework Directive

    OpenAIRE

    Alaoui, Khadija Sossey; Galoux, Daniel; Rosillon, Francis

    2014-01-01

    Macrophytes are among the major groups of organisms that the Water Framework Directive (WFD) recommends should be used in assessing the status of natural lakes. The use of macrophytes in reservoir monitoring is still limited and further studies are needed on their inter-calibration and sources of variation. Many status assessment methods based on macrophyte communities have been defined for lakes. Nevertheless, few of them have been tested for reservoirs. The purpose of the study is to hig...

  8. Response of littoral macrophytes to water level fluctuations in a storage reservoir

    OpenAIRE

    Krolová M.; Čížková H.; Hejzlar J.; Poláková S.

    2013-01-01

    Lakes and reservoirs that are used for water supply and/or flow regulations have usually poorly developed littoral macrophyte communities, which impairs ecological potential in terms of the EU Water Framework Directive. The aim of our study was to reveal controlling factors for the growth of littoral macrophytes in a storage reservoir with fluctuating water level (Lipno Reservoir, Czech Republic). Macrophytes occurred in this reservoir only in the eulittoral zone i.e., the shoreline region be...

  9. Temporal and habitat distribution of macrophytes in lowland eutrophic reservoir Gruža in Serbia

    OpenAIRE

    Topuzović, Marina; Pavlović, Dragana; Ostojić, Aleksandar

    2016-01-01

    Background and Purpose: The research in this paper are based on the study of the distribution in time and space of macrophytes along the different parts of shoreline of Gruža Reservoir and emphasize the importance of establishing relations between distribution, diversity and mass of macrophytes and the ecological conditions of the environment. Development diversity of macrophytes needs to be constantly monitored and their regulation is necessary for Reservoir conservation, especially because ...

  10. Invasive crayfish threaten the development of submerged macrophytes in lake restoration.

    Directory of Open Access Journals (Sweden)

    Jessica E M van der Wal

    Full Text Available Submerged macrophytes enhance water transparency and aquatic biodiversity in shallow water ecosystems. Therefore, the return of submerged macrophytes is the target of many lake restoration projects. However, at present, north-western European aquatic ecosystems are increasingly invaded by omnivorous exotic crayfish. We hypothesize that invasive crayfish pose a novel constraint on the regeneration of submerged macrophytes in restored lakes and may jeopardize restoration efforts. We experimentally investigated whether the invasive crayfish (Procambarus clarkii Girard affects submerged macrophyte development in a Dutch peat lake where these crayfish are expanding rapidly. Seemingly favourable abiotic conditions for macrophyte growth existed in two 0.5 ha lake enclosures, which provided shelter and reduced turbidity, and in one lake enclosure iron was added to reduce internal nutrient loading, but macrophytes did not emerge. We transplanted three submerged macrophyte species in a full factorial exclosure experiment, where we separated the effect of crayfish from large vertebrates using different mesh sizes combined with a caging treatment stocked with crayfish only. The three transplanted macrophytes grew rapidly when protected from grazing in both lake enclosures, demonstrating that abiotic conditions for growth were suitable. Crayfish strongly reduced biomass and survival of all three macrophyte species while waterfowl and fish had no additive effects. Gut contents showed that crayfish were mostly carnivorous, but also consumed macrophytes. We show that P. clarkii strongly inhibit macrophyte development once favourable abiotic conditions for macrophyte growth are restored. Therefore, expansion of invasive crayfish poses a novel threat to the restoration of shallow water bodies in north-western Europe. Prevention of introduction and spread of crayfish is urgent, as management of invasive crayfish populations is very difficult.

  11. Efectos del pastoreo sobre el banco de semillas germinable y la vegetación establecida en pastizales de montaña del centro de Argentina Grazing effects on the germinable seed bank and standing vegetation in mountain grasslands from central Argentina

    Directory of Open Access Journals (Sweden)

    SEBASTIÁN MARQUEZ

    2002-06-01

    semillas persistente a corto y a largo plazo. El pastoreo, o su ausencia, no modifica la abundancia en el banco de semillas de la mayoría de las especies, sin embargo, las dos especies que sí cambian de manera importante su presencia en el banco, responden a dos estrategias opuestas, según lo observado por otros autores, una domina la productividad primaria del ecosistema en ausencia del pastoreo, la otra, ocuparía un papel importante en la cicatrización de huecos a la escala de microparche en sitios muy perturbadosWe studied the effect of grazing on the standing vegetation and the germinable soil seed bank in natural mountain grasslands at Pampa de Achala, Córdoba Province, Argentine. We analyzed the germinable seed bank at two depths (0-5 and 5-10 cm in five replicates from sites grazed at a moderate to intense grazing intensity, and in five replicates from sites excluded from herbivores during the last 10 years. We recorded species frequency on the standing vegetation and species abundance in the germinable seed bank. Grazing did not produce significant changes in the number of species of the standing vegetation, but produced an increase in species diversity due to a decrease in the dominance of perennial grasses such as Deyeuxia hieronymi and Festuca tucumanica. We registered only three alien species in the grasslands under study. Grazing did not produce significant changes in the seed bank richness and diversity. Average seed bank density significantly did not change after grazing, however, the density of the annual grass Muhlenbergia peruviana increased, while that of the tussock grass Deyeuxia hieronymi decreased in grazed plots. Seeds present in litter at the excluded sites comprised 20 % of the total number of species and 43 % of the total seed density. Ordination analysis, taking into account floristic composition of standing vegetation and the germinable seed bank, showed higher segregation between grazed-ungrazed samples than samples from vegetation and

  12. Aquatic macrophyte diversity of the Pantanal wetland and upper basin.

    Science.gov (United States)

    Pott, V J; Pott, A; Lima, L C P; Moreira, S N; Oliveira, A K M

    2011-04-01

    This is a short review of the state of the art concerning diversity of aquatic macrophytes and the main aquatic vegetation types in the Brazilian Pantanal wetland and upper watershed. There are ca. 280 species of aquatic macrophytes on the Pantanal floodplain, with scarce endemism. On the upper watershed, Cerrado wetlands (veredas) and limestone springs have a distinct flora from the Pantanal, with twice the species richness. As a representative case of aquatic habitats influenced by river flood, some primary data are presented for the Pantanal Matogrossense National Park and associated Acurizal Preserve, analysing the floristic similarity among aquatic vegetation types. We comment on problems of conservation and observe that Panicum elephantipes Nees is one of the few natives to compete with the invasive Urochloa arrecta (Hack. ex T. Durand & Schinz) Morrone & Zuloaga.

  13. Aquatic macrophyte diversity of the Pantanal wetland and upper basin

    Directory of Open Access Journals (Sweden)

    VJ. Pott

    Full Text Available This is a short review of the state of the art concerning diversity of aquatic macrophytes and the main aquatic vegetation types in the Brazilian Pantanal wetland and upper watershed. There are ca. 280 species of aquatic macrophytes on the Pantanal floodplain, with scarce endemism. On the upper watershed, Cerrado wetlands (veredas and limestone springs have a distinct flora from the Pantanal, with twice the species richness. As a representative case of aquatic habitats influenced by river flood, some primary data are presented for the Pantanal Matogrossense National Park and associated Acurizal Preserve, analysing the floristic similarity among aquatic vegetation types. We comment on problems of conservation and observe that Panicum elephantipes Nees is one of the few natives to compete with the invasive Urochloa arrecta (Hack. ex T. Durand & Schinz Morrone & Zuloaga.

  14. Aquatic macrophyte community varies in urban reservoirs with different degrees of eutrophication

    Directory of Open Access Journals (Sweden)

    Suelen Cristina Alves da Silva

    2014-06-01

    Full Text Available AIM: Investigate spatial and temporal variation in the aquatic macrophyte community in four urban reservoirs located in Curitiba metropolitan region, Brazil. We tested the hypothesis that aquatic macrophyte community differ among reservoirs with different degrees of eutrophication. METHODS: The reservoirs selected ranged from oligotrophic/mesotrophic to eutrophic. Sampling occurred in October 2011, January 2012 and June 2012. Twelve aquatic macrophytes stands were sampled at each reservoir. Species were identified and the relative abundance of aquatic macrophytes was estimated. Differences among reservoirs and over sampling periods were analyzed: i through two‑way ANOVAs considering the stand extent (m and the stand biodiversity - species richness, evenness, Shannon-Wiener index and beta diversity (species variation along the aquatic macrophyte stand; and ii through PERMANOVA considering species composition. Indicator species that were characteristic for each reservoir were also identified. RESULTS: The aquatic macrophyte stand extent varied among reservoirs and over sampling periods. Species richness showed only temporal variation. On the other hand, evenness and Shannon-Wiener index varied only among reservoirs. The beta diversity of macrophyte stands did not vary among reservoirs or over time, meaning that species variability among aquatic macrophyte stands was independent of the stand extent and reservoir eutrophication. Community composition depended on the reservoir and sampling period. CONCLUSIONS: Our results support our initial expectation that reservoirs of different degrees of eutrophication have different aquatic macrophyte communities. As a consequence, each reservoir had particular indicator species. Therefore, monitoring and management efforts must be offered for each reservoir individually.

  15. Patterns of the aquatic macrophyte cover in Cachoeira Dourada Reservoir (GO-MG

    Directory of Open Access Journals (Sweden)

    L. M Bini

    Full Text Available The relationship between the aquatic macrophyte cover in upper segments of tributaries and this cover in these tributaries but near the reservoir's main body was tested. Sixteen taxa belonging to 12 families of aquatic macrophytes were recorded in Cachoeira Dourada Reservoir. The most frequent species were Eichhornia azurea (frequency of occurrence = 92%; n = 37 sites and E. crassipes (44%. Upper segments of the tributaries were the main areas colonized by these aquatic macrophytes. The positive relationship between the aquatic macrophyte cover between the upper and lower segments of tributaries indicates the importance of dispersion in the colonization of the arms and the reservoir's main body.

  16. Patterns of the aquatic macrophyte cover in Cachoeira Dourada Reservoir (GO-MG).

    Science.gov (United States)

    Bini, L M; Oliveira, L G; Souza, D C; Carvalho, P; Pinto, M P

    2005-02-01

    The relationship between the aquatic macrophyte cover in upper segments of tributaries and this cover in these tributaries but near the reservoir's main body was tested. Sixteen taxa belonging to 12 families of aquatic macrophytes were recorded in Cachoeira Dourada Reservoir. The most frequent species were Eichhornia azurea (frequency of occurrence=92%; n=37 sites) and E. crassipes (44%). Upper segments of the tributaries were the main areas colonized by these aquatic macrophytes. The positive relationship between the aquatic macrophyte cover between the upper and lower segments of tributaries indicates the importance of dispersion in the colonization of the arms and the reservoir's main body.

  17. Arsenic rich iron plaque on macrophyte roots - an ecotoxicological risk?

    Energy Technology Data Exchange (ETDEWEB)

    Taggart, M.A. [School of Biological Sciences, University of Aberdeen, Cruickshank Bld, St Machar Drive, Aberdeen, AB24 3UU (United Kingdom); Instituto de Investigacion en Recursos Cinegeticos, IREC (CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005 Ciudad Real (Spain)], E-mail: mark.taggart@uclm.es; Mateo, R. [Instituto de Investigacion en Recursos Cinegeticos, IREC (CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005 Ciudad Real (Spain); Charnock, J.M.; Bahrami, F. [Synchrotron Radiation Department, CCLRC Daresbury Laboratory, Warrington, Cheshire, WA4 4AD (United Kingdom); Green, A.J. [Department of Wetland Ecology, Estacion Biologica de Donana, CSIC, Pabellon del Peru, Avenida Maria Luisa s/n, 41013 Seville (Spain); Meharg, A.A. [School of Biological Sciences, University of Aberdeen, Cruickshank Bld, St Machar Drive, Aberdeen, AB24 3UU (United Kingdom)

    2009-03-15

    Arsenic is known to accumulate with iron plaque on macrophyte roots. Three to four years after the Aznalcollar mine spill (Spain), residual arsenic contamination left in seasonal wetland habitats has been identified in this form by scanning electron microscopy. Total digestion has determined arsenic concentrations in thoroughly washed 'root + plaque' material in excess of 1000 mg kg{sup -1}, and further analysis using X-ray absorption spectroscopy suggests arsenic exists as both arsenate and arsenite. Certain herbivorous species feed on rhizomes and bulbs of macrophytes in a wide range of global environments, and the ecotoxicological impact of consuming arsenic rich iron plaque associated with such food items remains to be quantified. Here, greylag geese which feed on Scirpus maritimus rhizome and bulb material in areas affected by the Aznalcollar spill are shown to have elevated levels of arsenic in their feces, which may originate from arsenic rich iron plaque. - Accumulation of metals with iron plaque on macrophyte roots in wetlands poses an ecotoxicological risk to certain herbivores.

  18. Vulnerabilities of macrophytes distribution due to climate change

    Science.gov (United States)

    Hossain, Kaizar; Yadav, Sarita; Quaik, Shlrene; Pant, Gaurav; Maruthi, A. Y.; Ismail, Norli

    2017-08-01

    The rise in the earth's surface and water temperature is part of the effect of climatic change that has been observed for the last decade. The rates of climate change are unprecedented, and biological responses to these changes have also been prominent in all levels of species, communities and ecosystems. Aquatic-terrestrial ecotones are vulnerable to climate change, and degradation of the emergent aquatic macrophyte zone would have contributed severe ecological consequences for freshwater, wetland and terrestrial ecosystems. Most researches on climate change effects on biodiversity are contemplating on the terrestrial realm, and considerable changes in terrestrial biodiversity and species' distributions have been detected in response to climate change. This is unfortunate, given the importance of aquatic systems for providing ecosystem goods and services. Thus, if researchers were able to identify early-warning indicators of anthropogenic environmental changes on aquatic species, communities and ecosystems, it would certainly help to manage and conserve these systems in a sustainable way. One of such early-warning indicators concerns the expansion of emergent macrophytes in aquatic-terrestrial ecotones. Hence, this review highlights the impact of climatic changes towards aquatic macrophytes and their possible environmental implications.

  19. Microphyte and macrophyte-based lagooning in tropical regions.

    Science.gov (United States)

    Noumsi, I M K; Nya, J; Akoa, A; Eteme, R A; Ndikefor, A; Fonkou, T; Brissaud, F

    2005-01-01

    A 720 m2 plant made of 8 ponds in series, set in Yaounde (Cameroon), was successively operated as a macrophyte-based system (type M) from November 1997 to October 98, a microphyte-based system (type m) from October 1999 to September 2000 and a combination of macrophyte and microphyte ponds (type M + m) from May to July 2001. Average applied loads varied over the years; from 420 kg. BOD5 ha(-1)d(-1) on the year 1997/98, the loads reached 510 kg BOD5 ha(-1)d(-1) in 1999/2000 and 500 in 2001. Though the system became more and more overloaded and sludge accumulated rapidly in the first ponds, it provided average removals of SS, BOD5 and COD that were always higher than 90% whatever the type of lagooning. Performances in the removal of SS, organic matter and the abatement of N-NH4+ and PO4(3-) did not significantly differ according to the type of lagooning and the applied load. Macrophyte lagooning did not show any definitive superiority as to nutrient removal when compared to microphyte lagooning. Microphyte lagooning was the most effective process in faecal indicators removal.

  20. Vulnerabilities of macrophytes distribution due to climate change

    Science.gov (United States)

    Hossain, Kaizar; Yadav, Sarita; Quaik, Shlrene; Pant, Gaurav; Maruthi, A. Y.; Ismail, Norli

    2016-06-01

    The rise in the earth's surface and water temperature is part of the effect of climatic change that has been observed for the last decade. The rates of climate change are unprecedented, and biological responses to these changes have also been prominent in all levels of species, communities and ecosystems. Aquatic-terrestrial ecotones are vulnerable to climate change, and degradation of the emergent aquatic macrophyte zone would have contributed severe ecological consequences for freshwater, wetland and terrestrial ecosystems. Most researches on climate change effects on biodiversity are contemplating on the terrestrial realm, and considerable changes in terrestrial biodiversity and species' distributions have been detected in response to climate change. This is unfortunate, given the importance of aquatic systems for providing ecosystem goods and services. Thus, if researchers were able to identify early-warning indicators of anthropogenic environmental changes on aquatic species, communities and ecosystems, it would certainly help to manage and conserve these systems in a sustainable way. One of such early-warning indicators concerns the expansion of emergent macrophytes in aquatic-terrestrial ecotones. Hence, this review highlights the impact of climatic changes towards aquatic macrophytes and their possible environmental implications.

  1. Aquatic macrophytes as indicators of heavy metal pollution of water in DTD canal system

    Directory of Open Access Journals (Sweden)

    Pajević Slobodanka P.

    2003-01-01

    Full Text Available The aim of this investigation was to establish the presence or absence of chemical contamination of water and the littoral zone (banks of Danube-Tisza-Danube (DTD canal system. The investigation covered the canal section from Bezdan to Prigrevica. By analyzing the chemical composition of dominant aquatic species in four locations of the section, we defined the species with the highest capacity to accumulate nutrients and heavy metals. Concentrations of P and K as well as of a beneficial element Na in the tissues of the analyzed macrophytes were both species- and site-dependent. The highest accumulation was registered for Ceratophyllum demersum while the species Elodea canadensis showed increased P and K accumulation values in the location Sombor. The lowest concentrations of almost all heavy metals were recorded near Sombor, indicating that this section suffered the lowest chemical pollution. Highest concentrations of all of the analyzed heavy metals were recorded in the tissue of Ceratophyllum demersum from the location Prigrevica, possibly due to the influx of polluted drainage waters from surrounding agricultural areas as well as industrial wastewaters. The obtained results showed that the enforcement of biomonitoring and analyses of other parameters indicative of ecosystem conditions might be useful for improved protection of areas experiencing a strong human impact.

  2. Extending one-dimensional models for deep lakes to simulate the impact of submerged macrophytes on water quality

    NARCIS (Netherlands)

    Sachse, R.; Petzoldt, T.; Blumstock, M.; Moreira, S.; Pätzig, M.; Rücker, J.; Janse, J.H.; Mooij, W.M.; Hilt, S.

    2014-01-01

    Submerged macrophytes can stabilise clear water conditions in shallow lakes. However, many existing models for deep lakes neglect their impact. Here, we tested the hypothesis that submerged macrophytes can affect the water clarity in deep lakes. A one-dimensional, vertically resolved macrophyte mode

  3. 湖南近自然森林经营主要林分类型土壤种子库特征研究%Studies on the characteristics of soil seed banks under main forest types of close-to-nature forest management in Hunan

    Institute of Scientific and Technical Information of China (English)

    罗佳; 田育新; 周小玲; 陈建华; 曾掌权; 李锡泉; 姚敏

    2014-01-01

    采用野外取样与种子萌发相结合的方法对湖南近自然森林经营主要林分类型(杉木、马尾松林)土壤种子库特征进行了研究。结果表明,杉木林土壤种子库主要由16种植物组成,其物种组成以草本为主,马尾松林20种,其种子库组成包括乔、灌、草生活型的物种。地上植被作为土壤种子库中种子来源,与种子库物种组成具有较高的相似性。种子库萌发过程呈现先草本植物种子萌发后木本植物的现象。杉木林、马尾松林土壤种子库密度具有一定相似性,杉木林、马尾松林最大值均出现在0~10 cm土壤层,分别为434.7粒/m2、523.6粒/m2。杉木林、马尾松林土壤种子库Margalef丰富度指数在10~20 cm土壤层中最低,最大值均出现在0~10 cm土壤层中。Shannon-Wiener多样性指数存在一定差异,在10~20 cm土壤层中,杉木林多样性指数为1.56,而马尾松林为1.34,为各层取样中多样性指数最低值。杉木林多样性指数最低值出现在枯枝落叶层,为0.70,多样性指数最高值均出现在0~10 cm土壤层中,分别为1.72、2.01。马尾松林土壤种子库在数量及质量上高于杉木林土壤种子库,马尾松林已逐渐演变为以马尾松占优势,青冈栎、香樟等乔木伴生的次生林,具有一定的林分自然更新能力。%By using the method of ifeld investigation and seed germination, the paper makes a comparison research about characteristics of soil seed bank under main forest types of close-to-nature forest management in Hunan (Cunninghamia lanceolata forest, Pinus massoniana forest). The result shows that, soil seed bank of Cunninghamia lanceolata forest is mainly composed of 16 plant species, and species composition is herbaceous mainly, 20 species of Pinus massoniana forest and its seed bank consists of tree, shrub and grass species of life forms. Aboveground vegetation as a source of seeds in the

  4. Restoring macrophyte diversity in shallow temperate lakes: biotic versus abiotic constraints

    NARCIS (Netherlands)

    Bakker, E.S.; Sarneel, J.M.; Gulati, R.D.; Liu, Z.; Van Donk, E.

    2013-01-01

    Although many lake restoration projects have led to decreased nutrient loads and increased water transparency, the establishment or expansion of macrophytes does not immediately follow the improved abiotic conditions and it is often unclear whether vegetation with high macrophyte diversity will retu

  5. Macrophyte-phytoplankton interactions: the relative importance of allelopathy versus other factors

    NARCIS (Netherlands)

    Mulderij, G.; Nes, van E.H.; Donk, van E.

    2007-01-01

    Submerged aquatic macrophytes are important in shallow aquatic ecosystems because they stabilize the macrophyte-dominated state by increasing water transparency in various ways. One of these is the excretion of allelopathic substances inhibitory to phytoplankton, but it is still controversial whethe

  6. Macrophyte-phytoplankton interactions: the relative importance of allelopathy versus other factors

    NARCIS (Netherlands)

    Mulderij, G.; van Nes, E.H.; Van Donk, E.

    2007-01-01

    Abstract Submerged aquatic macrophytes are important in shallow aquatic ecosystems because they stabilize the macrophyte-dominated state by increasing water transparency in various ways. One of these is the excretion of allelopathic substances inhibitory to phytoplankton, but it is still controversi

  7. Competition between free-floating and submerged macrophytes in a future of climate change

    NARCIS (Netherlands)

    Netten, J.J.C.

    2011-01-01


    This research was about the asymmetric competition between free-floating and submerged macrophytes in shallow freshwater ecosystems. I studied the effect of climate change on the dominance of free-floating macrophytes in temperate regions. The research approach was a combination of outdoor me

  8. Competition between free-floating and submerged macrophytes in a future of climate change

    NARCIS (Netherlands)

    Netten, J.J.C.

    2011-01-01


    This research was about the asymmetric competition between free-floating and submerged macrophytes in shallow freshwater ecosystems. I studied the effect of climate change on the dominance of free-floating macrophytes in temperate regions. The research approach was a combination of outdoor

  9. Macrophyte species distribution, indices of biotic integrity and sampling intensity in isolated Florida marshes

    Science.gov (United States)

    This study tested macrophyte condition metrics calculated after decreasing the effort and area of sampling by 33% to 66%, as tested in 74 emergent isolated wetlands. Four belted transects from wetland edge to center were established and rooted macrophytes were identified. The eff...

  10. Invertebrate grazing during the regenerative phase affects the ultimate structure of macrophyte communities

    NARCIS (Netherlands)

    Elger, A.F.; Willby, N.; Cabello-Martinez, M.

    2009-01-01

    1. Although the biomass of freshwater macrophytes consumed by invertebrate herbivores (excluding crayfish) is usually low, there is growing evidence that invertebrates do exert a structuring effect on macrophyte communities. To explain this, we postulated that the effect of invertebrates may be conc

  11. Effects of the herbicide 2,4-D on the growth of nine aquatic macrophytes

    NARCIS (Netherlands)

    Belgers, J.D.M.; Lieverloo, van R.J.; Pas, van der L.J.T.; Brink, van den P.J.

    2007-01-01

    A study was conducted to determine the effect of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) on nine submersed macrophyte species. The first objective of the study was to investigate the sensitivity of various endpoints in macrophyte toxicity tests. A second objective was to investigate the

  12. Experimental Effects of Lime Application on Aquatic Macrophytes: 4. Growth Response of Three Species

    Science.gov (United States)

    2007-04-01

    James PURPOSE: This investigation examined the growth response of three macrophyte species ( Elodea canadensis, Stuckenia pectinata, and Vallisnaria...different macrophyte species. These hypotheses were tested using experimental mesocosms. METHODS: Elodea canadensis, Stuckenia pectinata, and...Snel, P. E. Zanstra, and R. J. Helder. 1982. The mechanism of bicarbonate assimilation by the polar leaves of Potamogeton and Elodea . CO2 concentrations

  13. First steps in the Central-Baltic intercalibration exercise on lake macrophytes: where do we start?

    NARCIS (Netherlands)

    Tóth, L.G.; Poikane, S.; Penning, W.E.; Free, G.; Mäemets, H.; Kolada, A.; Hanganu, J.

    2008-01-01

    The Water Framework Directive (WFD 2000) defines macrophytes as one of the biological groups required for the ecological assessment of European surface waters. Several indices for macrophyte assessment have been proposed or are currently in use by different European states. As a first step towards p

  14. Macrophyte-phytoplankton interactions: the relative importance of allelopathy versus other factors

    NARCIS (Netherlands)

    Mulderij, G.; van Nes, E.H.; Van Donk, E.

    2007-01-01

    Abstract Submerged aquatic macrophytes are important in shallow aquatic ecosystems because they stabilize the macrophyte-dominated state by increasing water transparency in various ways. One of these is the excretion of allelopathic substances inhibitory to phytoplankton, but it is still

  15. Macrophyte-phytoplankton interactions: the relative importance of allelopathy versus other factors

    NARCIS (Netherlands)

    Mulderij, G.; Nes, van E.H.; Donk, van E.

    2007-01-01

    Submerged aquatic macrophytes are important in shallow aquatic ecosystems because they stabilize the macrophyte-dominated state by increasing water transparency in various ways. One of these is the excretion of allelopathic substances inhibitory to phytoplankton, but it is still controversial

  16. Seed quality in informal seed systems

    NARCIS (Netherlands)

    Biemond, P.C.

    2013-01-01

    Keywords:     informal seed systems, seed recycling, seed quality, germination, seed pathology, seed health, seed-borne diseases, mycotoxigenic fungi, Fusarium verticillioides, mycotoxins, Vigna unguiculata, Zea mays, Nigeria.   Seed is a crucial input for agricultural producti

  17. Seed quality in informal seed systems

    NARCIS (Netherlands)

    Biemond, P.C.

    2013-01-01

    Keywords:     informal seed systems, seed recycling, seed quality, germination, seed pathology, seed health, seed-borne diseases, mycotoxigenic fungi, Fusarium verticillioides, mycotoxins, Vigna unguiculata, Zea mays, Nigeria.   Seed is a crucial input for agricultural

  18. Carbonic anhydrase levels and internal lacunar CO/sub 2/ concentrations in aquatic macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, C.I.

    1979-01-01

    Carbonic anhydrase levels were examined in a variety of aquatic macrophytes from different habitats. In general, carbonic anhydrase levels increased across the habitat gradient such that activities were low in submersed aquatic macrophytes and high in emergent macrophytes with floating-leaved and free-floating plants exhibiting intermediate activities. Internal lacunar CO/sub 2/ concentrations were analyzed in relation to carbonic anhydrase activities. There was no correlation between these two parameters. Internal CO/sub 2/ concentrations ranged from low to high in submersed macrophytes, but were low in floating-leaved and emergent macrophytes. The observed internal CO/sub 2/ concentrations are discussed in relation to the individual morphologies of the plants and the environments in which they occurred.

  19. Effects of altered estuarine submerged macrophyte bed cover on the omnivorous Cape stumpnose Rhabdosargus holubi.

    Science.gov (United States)

    Sheppard, J N; Whitfield, A K; Cowley, P D; Hill, J M

    2012-03-01

    The ecological importance of submerged macrophyte beds to fishes within estuaries was investigated through the example of the ubiquitous Cape stumpnose Rhabdosargus holubi, an omnivorous, vegetation and estuary-dependent species, using stable-isotope techniques and long-term abundance (catch-per-unit-effort) data from the East Kleinemonde Estuary, South Africa. Outputs from a Bayesian mixing model using δ(13) C and δ(15) N signatures indicated that the submerged macrophytes Ruppia cirrhosa and Potamogeton pectinatus were not a primary source of nutrition for R. holubi, confirming previous work that revealed that macrophytes are consumed but not digested. Long-term seine netting data showed reduced abundance of R. holubi during a prolonged period of macrophyte senescence, suggesting that submerged macrophyte habitats provide shelter that reduces mortality (predation risk) and a food-rich foraging area. © 2012 SAIAB. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  20. Functional groups of entomofauna associated to aquatic macrophytes in Correntoso river, Rio Negro sub-region, Pantanal, Mato Grosso do Sul State, Brazil - doi: 10.4025/actascibiolsci.v34i1.7822

    Directory of Open Access Journals (Sweden)

    José Sabino

    2011-11-01

    Full Text Available This work aimed to study the structure of functional groups of entomofauna associated to aquatic macrophytes in Correntoso river, Rio Negro sub-region, Pantanal, Mato Grosso do Sul State, Brazil. Six samples were taken in different seasonal periods; ebb, dry and wet. The organisms were collected using D net (300 m mesh, sweeping five times through the roots of macrophyte banks at each sample session. Three environments were compared (open, intermediary, close using data from six collection sites, through which were analyzed absolute abundance, observed richness of families and the sampled specimens were also separated in functional groups. A total of 60 families from 12 orders of Insecta were registered, totaling 19,773 sampled insects. The largest number of families was categorized into predators functional group, with 34 families collected, followed by the collectors with 17, shredders-herbivores ten and scrapers eight.

  1. Role of macrophyte life forms in driving periphytic microalgal assemblages in a Brazilian reservoir

    Directory of Open Access Journals (Sweden)

    Ubirajara L. Fernandes

    2015-08-01

    Full Text Available Macrophytes play several roles in aquatic ecosystems, including the provision of habitat for many aquatic organisms, especially the periphyton. The aims of this study were to characterize the structure of periphytic microalgal assemblages on different aquatic macrophyte life forms in order to establish similarities between assemblages from nearby sampling sites. We hypothesized that i aquatic macrophytes with different life forms and morphological characteristics could differently influence the structure of the periphyton and that ii the greatest similarity in periphyton composition should be observed among macrophytes that occupy the same sampling site. The study was conducted from 2006 to 2008 in the Thomaz Osterne de Alencar reservoir (Crato City, Ceará State, Brazil and involved the taxonomic surveying of microalgae attached to five different macrophytes with the application of structural descriptors (richness, abundance, frequency, diversity and equitability. A total of 127 taxa, of which 44% belonged to the Chlorophyta, were identified. The microalgae assemblages showed high species richness on Salvinia auriculata Aubl., a free-floating macrophyte, and large abundance on Apalanthe granatensis (Humb. & Bonpl. Planch., a submerged anchored macrophyte. ANOVA indicated that periphyton significantly varied among the macrophytes investigated, and nearby sampling sites showed no structural similarities in microalgal assemblages. In general, we can conclude that the structure of periphyton assemblages is influenced by the substrate (i.e., macrophyte organ, as this can not only promote high diversity and equitability but can also be a predictor of dissimilarity in the distribution and frequency of occurrence of microalgae. These results reinforce the findings of other studies that have shown that macrophytes play an important role in structuring the periphyton assemblages.

  2. Submerged macrophytes mitigate direct and indirect insecticide effects in freshwater communities.

    Directory of Open Access Journals (Sweden)

    William R Brogan

    Full Text Available Understanding how ecological interactions mitigate the impacts of perturbations such as pesticides in biological communities is an important basic and applied question for ecologists. In aquatic ecosystems, new evidence from microcosm experiments suggests that submerged macrophytes can buffer cladocerans from pulse exposures to the widely used insecticide malathion, and that mitigation increases with macrophyte density. However, whether these results scale up to more complex aquatic communities where ecological interactions such as competition can alter toxicity is unknown. Further, macrophyte abilities to mitigate different insecticide exposure scenarios (i.e. single versus repeated pulses have never been tested. To address these gaps, we performed a factorial mesocosm experiment examining the influence of four macrophyte treatments (0, 10, 50, or 100 Elodea Canadensis shoots planted per mesocosm crossed with three malathion exposure scenarios (no insecticide, single pulse, repeated pulses on aquatic communities containing zooplankton, phytoplankton, periphyton, two snail species, and larval amphibians. In the absence of macrophytes, single malathion pulses caused short-term declines in cladoceran abundance followed by their rapid recovery, which precluded any indirect effects (i.e. trophic cascades. However, repeated malathion pulses caused cladoceran extinctions, resulting in persistent phytoplankton blooms and reduced abundance of one snail species. In contrast, with macrophytes present, even at low density, malathion had no effect on any taxa. We also discovered novel effects of macrophytes on the benthic food web. In the two highest macrophyte treatments, we observed trends of reduced periphyton biomass, decreased abundance of one snail species, and decreased amphibian time to and mass at metamorphosis. To our knowledge, this is the first evidence of negative submerged macrophyte effects on amphibians, a taxa of global conservation concern

  3. Efeito da interação do nicosulfuron e chlorpyrifos sobre o banco de sementes e os atributos microbianos do solo Effect of sequential nicosulfuron and chlorpyrifos application on seed bank and soil microbial characteristics

    Directory of Open Access Journals (Sweden)

    Taciane Almeida de Oliveira

    2009-06-01

    sementes e sobre a atividade microbiana do solo.In the period of competition of weeds and the incidence of fall armyworm in the corn crop there is a need for herbicide and insecticide such as nicosulfuron and chlorpyrifos application within short time intervals. The aim of this study was to evaluate the effect of sequential applications of nicosulfuron and chlorpyrifos on the emergence of seedlings of the seed bank in the soil, the basal CO2 emission rate, and the microbial biomass carbon (MBC of soil. Sequential applications of nicosulfuron (doses from 0 to 64 g ha-1 with or without chlorpyrifos (0 and 240 g ha-1 were performed. At 20, 40 and 60 days after application (DAA of the products, the species of all seedlings that emerged from the seed bank were identified, and the frequency, density and abundance estimated, as well as the importance value IV. Sixty DAA the CO2 emission rate and CBM were were also determined, and based on the relationship between the accumulated CO2 and total soil MBC the metabolic coefficient (qCO2 was estimated. The application of nicosulfuron rates of over 20 g ha-1 severely affected the seedling dry weight and number of species. In the presence of the herbicide, the species with highest IV were Boehavia diffusa and Commelina bengalensis. There was a decrease in the basal soil respiration rate with increasing nicosulfuron doses, in the presence as well as in the absence of the insecticide chlorpyrifos. There was a linear decrease in MBC in all cases regardless of the chlorpyrifos application, although the reduction was 4.5 times greater in soil that received the combined application of the insecticide and nicosulfuron. The qCO2 confirmed the negative effect of the application of insecticide and herbicide. It was concluded that the application of chlorpyrifos + nicosulfuron causes a negative impact on the seeds in the soil and the soil microbial activity.

  4. Physical and chemical properties of substrates produced using macrophytes aquatics

    Directory of Open Access Journals (Sweden)

    Walda Monteiro Farias

    2013-12-01

    Full Text Available Aquatic macrophytes are widely used as bioindicators of water quality because their proliferation usually occurs in eutrophic water sources and has hit several parts of Brazil and the world, restricted the multiple uses of aquatic ecosystems. However, this group of plants is able to retain considerable amounts of nutrients, presenting high productivity and high growth rate, thus, a good source of biomass for use in the production of substrates. In order to evaluate the potential of aquatic macrophytes water hyacinth (Eichhornia crassipes Solms., water lettuce (Pistia stratiotes L. and cattail (Typha domingensis Pers. in the production of substrates was performed in this work, the physical and chemical characterization and evaluation of the degree of humification. The treatments were arranged in a 3 × 4 factorial, completely randomized design with three replications. All substrates produced with 100% macrophyte density present within the limits of 400 kg m-3, considered ideal. The composite substrates with water hyacinth and water lettuce are with the electrical conductivity of 0,79 a 2,49 dS m-1 within recommended. organic compounds produced are considered mature and have high levels of nitrogen phosphorus and potassium; The substrate produced with 70% water lettuce +30 % dung and 70% composed of cattail manure +20% +10% topsoil and 70 +30% cattail manure have C/N ratio within the considered ideal; the humification ratio and humification index, except for the four treatments (70 % water lettuce manure +30%, 5 (100% water hyacinth and 8 (70% water hyacinth manure +30% are within the considered ideal, the percentage of humic acids and polymerization rate, except for treatments 1 (100% water lettuce and 12 (100% cattail, are shown below the ideal.

  5. Bank development; bank development efficiency; bank management; bank.

    OpenAIRE

    Самородов, Б. В.

    2014-01-01

    In the paper the theoretical research of determination of the essence of “management of bank financial development” is realized. The analysis is performed on the basis of substantial considering and comparing the philosophy and economical definitions of the components of its definition.

  6. Seed dispersal in fens

    Science.gov (United States)

    Middleton, B.; Van Diggelen, R.; Jensen, K.

    2006-01-01

    Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and reducing genetic exchange. Species in fragmented wetlands may have lower reproductive success, which can lead to biodiversity loss. While fens may have always been relatively isolated from each other, they have become increasingly fragmented in modern times within agricultural and urban landscapes in both Europe and North America. Dispersal by water, animals and wind has been hampered by changes related to development in landscapes surrounding fens. Because the seeds of certain species are long-lived in the seed bank, frequent episodes of dispersal are not always necessary to maintain the biodiversity of fens. However, of particular concern to restoration is that some dominant species, such as the tussock sedge Carex stricta, may not disperse readily between fens. Conclusions: Knowledge of seed dispersal can be used to maintain and restore the biodiversity of fens in fragmented landscapes. Given that development has fragmented landscapes and that this situation is not likely to change, the dispersal of seeds might be enhanced by moving hay or cattle from fens to damaged sites, or by reestablishing lost hydrological connections. ?? IAVS; Opulus Press.

  7. Cord-Blood Banking

    Science.gov (United States)

    ... to Be Smart About Social Media Cord-Blood Banking KidsHealth > For Parents > Cord-Blood Banking Print A ... for you and your family. About Cord-Blood Banking Cord-blood banking basically means collecting and storing ...

  8. 12 CFR 619.9140 - Farm Credit bank(s).

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Farm Credit bank(s). 619.9140 Section 619.9140 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM DEFINITIONS § 619.9140 Farm Credit bank(s). Except as otherwise defined, the term Farm Credit bank(s) includes Farm Credit...

  9. Plant based phosphorus recovery from wastewater via algae and macrophytes.

    Science.gov (United States)

    Shilton, Andrew N; Powell, Nicola; Guieysse, Benoit

    2012-12-01

    At present, resource recovery by irrigation of wastewater to plants is usually driven by the value of the water resource rather than phosphorus recovery. Expanded irrigation for increased phosphorus recovery may be expected as the scarcity and price of phosphorus increases, but providing the necessary treatment, storage and conveyance comes at significant expense. An alternative to taking the wastewater to the plants is instead to take the plants to the wastewater. Algal ponds and macrophyte wetlands are already in widespread use for wastewater treatment and if harvested, would require less than one-tenth of the area to recover phosphorus compared to terrestrial crops/pastures. This area could be further decreased if the phosphorus content of the macrophytes and algae biomass was tripled from 1% to 3% via luxury uptake. While this and many other opportunities for plant based recovery of phosphorus exist, e.g. offshore cultivation, much of this technology development is still in its infancy. Research that enhances our understanding of how to maximise phosphorus uptake and harvest yields; and further add value to the biomass for reuse would see the recovery of phosphorus via plants become an important solution in the future.

  10. Efficiency of aquatic macrophytes to treat Nile tilapia pond effluents

    Directory of Open Access Journals (Sweden)

    Henry-Silva Gustavo Gonzaga

    2006-01-01

    Full Text Available The effluents from fish farming can increase the quantity of suspended solids and promote the enrichment of nitrogen and phosphorus in aquatic ecosystems. In this context, the aim of this work was to evaluate the efficiency of three species of floating aquatic macrophytes (Eichhornia crassipes, Pistia stratiotes and Salvinia molesta to treat effluents from Nile tilapia culture ponds. The effluent originated from a 1,000-m² pond stocked with 2,000 male Nile tilapia Oreochromis niloticus. The treatment systems consisted of 12 experimental tanks, three tanks for each macrophyte species, and three control tanks (without plants. Water samples were collected from the: (i fish pond source water, (ii effluent from fish pond and (iii effluents from the treatment tanks. The following water variables were evaluated: turbidity, total and dissolved nitrogen, ammoniacal-N, nitrate-N, nitrite-N, total phosphorus and dissolved phosphorus. E. crassipes and P. stratiotes were more efficient in total phosphorus removal (82.0% and 83.3%, respectively and total nitrogen removal (46.1% and 43.9%, respectively than the S. molesta (72.1% total phosphorus and 42.7% total nitrogen and the control (50.3% total phosphorus and 22.8% total nitrogen, indicating that the treated effluents may be reused in the aquaculture activity.

  11. Monitoring the dynamics of an invasive emergent macrophyte community using operational remote sensing data

    Science.gov (United States)

    Albright, T.P.; Ode, D.J.

    2011-01-01

    Potamogeton crispus L. (curly pondweed) is a cosmopolitan aquatic macrophyte considered invasive in North America and elsewhere. Its range is expanding and, on individual water bodies, its coverage can be dynamic both within and among years. In this study, we evaluate the use of free and low-cost satellite remote sensing data to monitor a problematic emergent macrophyte community dominated by P. crispus. Between 2000 and 2006, we acquired eight satellite images of 24,000-ha Lake Sharpe, South Dakota (USA). During one of the dates for which satellite imagery was acquired, we sampled the lake for P. crispus and other emergent macrophytes using GPS and photography for documentation. We used cluster analysis to assist in classification of the satellite imagery and independently validated results using the field data. Resulting estimates of emergent macrophyte coverage ranged from less than 20 ha in 2002 to 245 ha in 2004. Accuracy assessment indicated 82% of image pixels were correctly classified, with errors being primarily due to failure to identify emergent macrophytes. These results emphasize the dynamic nature of P. crispus-dominated macrophyte communities and show how they can be effectively monitored over large areas using low-cost remote sensing imagery. While results may vary in other systems depending on water quality and local flora, such an approach could be applied elsewhere and for a variety of macrophyte communities. ?? Springer Science+Business Media B.V. 2010.

  12. Responses of aquatic macrophyte cover and productivity to flooding variability on the Amazon floodplain.

    Science.gov (United States)

    Silva, Thiago S F; Melack, John M; Novo, Evlyn M L M

    2013-11-01

    Macrophyte net primary productivity (NPP) is a significant but understudied component of the carbon budget in large Amazonian floodplains. Annual NPP is determined by the interaction between stem elongation (vertical growth) and plant cover changes (horizontal expansion), each affected differently by flood duration and amplitude. Therefore, hydrological changes as predicted for the Amazon basin could result in significant changes in annual macrophyte NPP. This study investigates the responses of macrophyte horizontal expansion and vertical growth to flooding variability, and its possible effects on the contribution of macrophytes to the carbon budget of Amazonian floodplains. Monthly macrophyte cover was estimated using satellite imagery for the 2003-2004 and 2004-2005 hydrological years, and biomass was measured in situ between 2003 and 2004. Regression models between macrophyte variables and river-stage data were used to build a semiempirical model of macrophyte NPP as a function of water level. Historical river-stage records (1970-2011) were used to simulate variations in NPP, as a function of annual flooding. Vertical growth varied by a factor of ca. 2 over the simulated years, whereas minimum and maximum annual cover varied by ca. 3.5 and 1.5, respectively. Results suggest that these processes act in opposite directions to determine macrophyte NPP, with larger sensitivity to changes in vertical growth, and thus maximum flooding levels. Years with uncommonly large flooding amplitude resulted in the highest NPP values, as both horizontal expansion and vertical growth were enhanced under these conditions. Over the simulated period, annual NPP varied by ca. 1.5 (1.06-1.63 TgC yr(-1) ). A small increasing trend in flooding amplitude, and by extension NPP, was observed for the studied period. Variability in growth rates caused by local biotic and abiotic factors, and the lack of knowledge on macrophyte physiological responses to extreme hydrological conditions

  13. Composição florística e distribuição sazonal do banco de sementes em Floresta Ombrófila Mista Aluvial, Araucária, PR Floristic composition and distribution of soil seed bank in Subtropical Ombrophilous Alluvial Forest in Araucaria, Parana State, Brazil

    Directory of Open Access Journals (Sweden)

    Saulo Henrique Weber

    2012-06-01

    Full Text Available Nesta pesquisa avaliou-se o banco de sementes do solo em um remanescente da Floresta Ombrófila Mista Aluvial, em Araucária, PR, através da análise quali-quantitativa da germinação. Adicionalmente, foi verificado se houve variação sazonal do banco. Localizado no Primeiro Planalto Paranaense, o remanescente encontra-se sob influência do rio Barigüi, tributário do rio Iguaçu. O delineamento estatístico foi inteiramente casualizado, com dez repetições, formadas por amostras compostas. O banco de sementes foi coletado em três estações do ano, sendo retiradas amostras de 10 cm de profundidade com serrapilheira, com auxílio de um gabarito quadrado de 40 cm de lado. As amostras de cada estação foram dispostas em caixas de madeira em casa de vegetação, por oito meses. Foi observada a ocorrência média, nas três estações, de 5.732 sementes m-2, pertencentes a 276 espécies, distribuídas em 120 gêneros e 54 famílias, num total de 34.780 sementes germinadas. O tamanho do banco de sementes não variou significativamente entre as estações do ano. A composição florística do banco de sementes é influenciada pelas áreas antropizadas do entorno.doi: 10.4336/2012.pfb.32.70.77In this research it was evaluated the potential of the soil seed bank in a remaining of Subtropical Ombrophilous Alluvial Forest (Araucaria Forest, by quali-quantitative analysis of seed germination. Additionally it was tested the occurrence of seasonal variation of the soil seed bank. The forest remaining located in Araucaria county, Parana State, Brazil, and it is influenced by Barigui river, affluent of Iguaçu river. It was used the completely randomized experimental design with ten replications. The soil seed bank was collected in three seasons at depth (of 10 cm plus litter, using a 0.40 m x 0.40 m sample square. The collected samples were placed in wood boxes in greenhouse, during 8 months. It was observed a season average of 5,732 individuals m-2

  14. Investment Banking

    OpenAIRE

    Oana Mihaela Vãsioiu

    2008-01-01

    The economic, financial and monetary changes had serious consequences not only on the level of providing the finance necessary for the development process but also on the level of providing the finance required for importing the basic food needs and rendering necessary production inputs. All these problems show the importance of “Banks” generally and “Investment Banks” particularly in the emerging and underdeveloped countries. Banks as financial institution or intermediary mobilize either nat...

  15. Consequences of Repeated Defoliation on Belowground Bud Banks of Carex brevicuspis (Cyperaceae) in the Dongting Lake Wetlands, China.

    Science.gov (United States)

    Chen, Xin-Sheng; Deng, Zheng-Miao; Xie, Yong-Hong; Li, Feng; Hou, Zhi-Yong; Wu, Chao

    2016-01-01

    Despite the predominant role of bud banks in the regeneration of clonal macrophyte populations, few studies have examined the way in which clonal macrophytes adjust the demographic features of bud banks to regulate population dynamics in response to defoliation in wetlands. We investigated the density and composition of bud banks under repeated defoliation in the wetland sedge Carex brevicuspis C. B. Clarke in the Dongting Lake wetlands, China. The density and biomass of rhizome buds and shoots did not decrease significantly in response to repeated defoliation over two consecutive years. The composition of bud banks, which consisted of long and short rhizome buds, also did not change significantly in response to repeated defoliation. Nevertheless, the ramet height and the shoot, root, and rhizome mass of C. brevicuspis declined significantly under repeated defoliation. Our findings suggest that bud banks are a conservative reproductive strategy that enables C. brevicuspis to tolerate a certain amount of defoliation. The maintenance of large bud banks after repeated defoliation may enable C. brevicuspis populations to regenerate and persist in disturbed habitats. However, bud bank density of C. brevicuspis might decline in the long term because the amount of carbon stored in rhizome buds and plants is reduced by frequent defoliation.

  16. Temporal and spatial distribution of macrophytes in the Gruža Reservoir (Serbia

    Directory of Open Access Journals (Sweden)

    Topuzović Marina

    2009-01-01

    Full Text Available A survey of aquatic macrophytes in the Gruža Reservoir (Serbia was conducted during the period 2007-2008. Detailed data on the actual condition of macrophytes were established and compared between four parts of the reservoir. The distributions of most aquatic macrophytes of the Gruža Reservoir are heterogeneous, with different values of the MMT and MMO indices and low values of the distribution ratio. Quantitative analysis indicates that the greatest diversity and abundance of species can be found in those parts of the reservoir with the shallowest water and greatest indentation of the shoreline.

  17. Simulating Retail Banking for Banking Students

    Science.gov (United States)

    Supramaniam, Mahadevan; Shanmugam, Bala

    2009-01-01

    The purpose of this study was to examine the implementation flow and development of retail bank management simulation based training system which could provide a comprehensive knowledge about the operations and management of banks for the banking students. The prototype of a Retail banking simulation based training system was developed based on…

  18. Sediment phosphate composition in relation to emergent macrophytes in the Doñana Marshes (SW Spain)

    Science.gov (United States)

    Reina, M.; Espinar, J.L.; Serrano, L.

    2006-01-01

    We have studied the effect of the presence of emergent macrophytes on the sediment phosphate composition of a eutrophic shallow marsh on the NE margin of Doñana (SW Spain). Top sediment and water samples were collected from both the open-water and the vegetated sites at three areas covered by different plant species: Scirpus maritimus, Juncus subulatus and Phragmites australis. The concentration of organic matter was significantly higher in the top sediment of sites covered by vegetation than in their adjacent open-water sites at the three vegetation areas. The P-fractional composition showed that the sediment was dominated by the inorganic P-fractions in all cases, reaching the highest concentration in the Ca-bound P-fraction (281–372 μg g−1 d.w.). The sum of all P-fractions was significantly higher in the top sediment of the sites covered by J. subulatus and S. maritimus than in their adjacent open-water sites, and so were the org-P fraction extracted by hot NaOH and the concentration of phytate within this fraction. Deposition of plant material on the top sediment of areas vegetated by J. subulatus and S. maritimus explains these differences. The P-fractional composition of the seeds from J. subulatus showed that they contained a large proportion of organic P-fractions, particularly of the fraction extracted by hot NaOH (1868 μg g−1 d.w., 85% of which was phytate). The presence of emergent macrophytes, therefore, influenced the distribution of P-fractions in the sediment depending on plant species. The P-bioavailability of shallow aquatic systems must be fully understood if wetlands are to be protected from further eutrophication.

  19. Composición y abundancia del banco de semillas en una región semiárida del trópico mexicano: patrones de variación espacial y temporal Composition and abundance of the seed bank in a semiaridregion in tropical Mexico: spatial and temporal patterns

    Directory of Open Access Journals (Sweden)

    Adriana Cano-Salgado

    2012-06-01

    Full Text Available Se estudió la estructura del banco de semillas en el valle semiárido de Zapotitlán, Puebla. El registro de la composición y abundancia del banco de semillas se realizó en 2 tipos de vegetación (tetechera y matorral espinoso en los microhábitats (bajo arbustos, espacio abierto y basureros de la hormiga granívora Pogonomyrmex barbatus. Las semillas se recolectaron en las épocas de secas, lluvias y finales de lluvias durante 2 años. No se encontraron diferencias en la densidad de semillas entre las épocas y años, pero sí hubo diferencias entre los microhábitats evaluados. El microhábitat del hormiguero presentó la mayor abundancia de semillas, lo que resalta la importancia de las hormigas en la conformación espacial de la estructura de las comunidades en estos ecosistemas. Se registraron semillas de 38 especies de plantas. La densidad promedio varió de 23 800 a 28 000 semillas m-2, concordando con otros registros de regiones semiáridas y áridas. Las especies más frecuentes fueron las anuales Eragrostis mexicana, Bouteloua barbata, Kallstroemia rosei y Portulaca pilosa. Los resultados muestran que la heterogeneidad de sitios y de microhábitats en esta zona es alta. Es necesaria la realización de más estudios sobre patrones espacio-temporales en los bancos de semillas y su relación con la vegetación en pie en zonas áridas y semiáridas en México.The seed bank structure in the semiarid valley of Zapotitlán, Puebla was studied. The record of the composition and abundance of the seed bank was conducted in 2 types of vegetation (tetechera and thorny scrub in the microhabitats (under shrubs, open space and refuse- dumps of granivorous ants Pogonomyrmex barbatus. Seed collection was carried out in dry, rainy and late rainy seasons for 2 years. There were no differences in seed density between seasons and years, but there were differences between microhabitats evaluated. The microhabitat of the ant refuse-dumps had the highest

  20. Functional diversity of macrophyte communities within and between Pyrenean lakes

    Directory of Open Access Journals (Sweden)

    Enric BALLESTEROS

    2009-02-01

    Full Text Available Submersed vegetation is a common feature in about 70% Pyrenean high mountain (>1500 m a.s.l. lakes. Isoetids and soft-water elodeids are common elements of this underwater flora and can form distinct vegetation units (i.e. patches of vegetation dominated by different species within complex mosaics of vegetation in shallow waters (<7 m. Since isoetids exert a strong influence on sediment biogeochemistry due to high radial oxygen loss, we examined the small scale characteristics of the lake environment (water and sediment associated to vegetation patches in order to ascertain potential functional differences among them. To do so, we characterised the species composition and biomass of the main vegetation units from 11 lakes, defined plant communities based on biomass data, and then related each community with sediment properties (redox and dissolved nutrient concentration in the pore water and water nutrient concentration within plant canopy. We also characterised lake water and sediment in areas without vegetation as a reference. A total of twenty-one vegetation units were identified, ranging from one to five per lake. A cluster analysis on biomass species composition suggested seven different macrophyte communities that were named after the most dominant species: Nitella sp., Potamogeton praelongus, Myriophyllum alterniflorum, Sparganium angustifolium, Isoetes echinospora, Isoetes lacustris and Carex rostrata. Coupling between macrophyte communities and their immediate environment (overlying water and sediment was manifested mainly as variation in sediment redox conditions and the dominant form of inorganic nitrogen in pore-water. These effects depended on the specific composition of the community, and on the allocation between above- and belowground biomass, and could be predicted with a model relating the average and standard deviation of sediment redox potential from 0 down to -20 cm, across macrophyte communities. Differences in pore

  1. Effect of HCA age on Germination Characteristics of Soil Seed Bank in Ningxia Desert Steppe%不同封育年限对宁夏荒漠草原土壤种子库萌发特征的影响研究

    Institute of Scientific and Technical Information of China (English)

    刘华; 王占军

    2016-01-01

    采用种子萌发法对不同封育时间(封育1年、封育3年、封育6年)样地的土壤种子库萌发特征进行了研究。结果表明:在0~5 cm土层不同封育年限土壤种子库的萌发基本趋势为,在第3天开始萌发,先增大后减小,在萌发的3~13 d为快速萌发期,萌发的最大值出现在第11天至第13天,在萌发的30 d后萌发的种子数较少;与0~5 cm土层相比,6~10 cm土层土壤种子库萌发较少,萌发曲线波动较小。说明土壤中可萌发种子数量不是随着封育年限的增加而增加。%The germination characteristics of soil seed bank were studied in 1 year, 3 years and 6 years of HCA with germi-nation method. The result showed that in the 3rd day, 0~5 cm soil layer HCA seeds began to germinate, increase and then decrease; from the 3rd~13th day, the germination speed became faster; the germination maximum was in the 11th ~13th day; after 30 days the germination seeds became fewer. Compared with the 0~5 cm soil layer, the 6~10 cm layer germi-nation seeds were fewer and its germination curve changed gently. The result showed that germinating seeds in the soil and HCA ages were not proportional.

  2. Interactions between nitrifying and denitrifying bacteria in gnotobiotic microcosms planted with the emergent macrophyte Glyceria maxima

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Duyts, H.; Blom, C.W.P.M.; Laanbroek, H.J.

    1998-01-01

    The population dynamics of the chemolithoautotrophic nitrifiers Nitrosomonas europaea and Nitrobacter winogradskyi were studied in gnotobiotic microcosms fed with ammonium in response to the presence or absence of the emergent macrophyte Glyceria maxima and the heterotrophic denitrifying bacterium P

  3. Long-term allelopathic control of phytoplankton by the submerged macrophyte Elodea nuttallii

    NARCIS (Netherlands)

    Vanderstukken, M.; Declerck, S.A.J.; Decaestecker, E.; Muylaert, K.

    2014-01-01

    Keywords: allelochemicals; chemical ecology; competition; nutrient limitation; shallow lakes Summary 1.It is well known that submerged macrophytes can suppress phytoplankton blooms in lakes and thus promote water quality and biodiversity. One of the possible mechanisms through which submerged macrop

  4. Studies on heavy metal accumulation in aquatic macrophytes from Sevan (Armenia) and Carambolim (India) lake systems

    Digital Repository Service at National Institute of Oceanography (India)

    Vardanyan, L.G.; Ingole, B.S.

    in root system. The representative macrophytes from two different physiographic locations show similar trends and order in accumulating different metals generally. Of the 14 metals investigated, 9 (Ca, Fe, Al, Cr, Cu, Ba, Ti, Co and Pb) showed higher rates...

  5. Three-Gorge Dam influences wetland macrophytes in middle and lower reaches of Yangtze

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Dongting Lake, located in the middle and lower reaches of Yangtze, is regarded as a lake during the water swelling period and a continent in the ebbing period. The construction of the Three-Gorge Dam has influenced the water level of Dongting Lake and the growth of wetland macrophytes in the area. In this study, the growth of main species of wetland macrophytes, such as Carex and Phragmites at Dongting Lake, was observed, and the hydraulic gradient, one of the main factors dominating the abundance and distribution of wetland macrophytes, was also studied at six stations in Dongting Lake area and the effect of the Three-Gorge Dam construction on the growth of wetland macrophytes was observed.

  6. Closely related freshwater macrophyte species, Ceratophyllum demersum and em>C. submersum, differ in temperature response

    DEFF Research Database (Denmark)

    Hyldgaard, Benita; Sorrell, Brian Keith; Brix, Hans

    2014-01-01

    1. The importance of temperature responses of photosynthesis and respiration in determining species distributions was compared in two closely related freshwater macrophytes, Ceratophyllum demersum and C. submersum. The two species differed significantly in response to temperature in the short and...

  7. PIXE analysis of chromium phytoaccumulation by the aquatic macrophytes Eicchornia crassipes

    Science.gov (United States)

    Espinoza-Quiñones, F. R.; Rizzutto, M. A.; Added, N.; Tabacniks, M. H.; Módenes, A. N.; Palácio, S. M.; Silva, E. A.; Rossi, F. L.; Martin, N.; Szymanski, N.

    2009-04-01

    The uptake of hexavalent chromium in free living floating aquatic macrophytes Eicchornia crassipes cultivated in non-toxic chromium-doped hydroponic solutions is presented. A Cr-uptake bioaccumulation experiment was carried out using healthy macrophytes grown in a temperature controlled greenhouse. Six samples of nutrient media and plants were collected during the 23 day experiment. Roots and leaves were acid digested with the addition of an internal Gallium standard, for thin film sample preparation and quantitative Cr analysis by PIXE method. The Cr 6+ mass uptake by the macrophytes reached up to 70% of the initial concentration, comparable to former results and literature data. The Cr-uptake data were described using a non-structural first order kinetic model. Due to low cost and high removal efficiency, living aquatic macrophytes E. crassipes are a viable biosorbent in an artificial wetland of a water effluent treatment plant.

  8. Effects of litter on substrate conditions and growth of emergent macrophytes

    NARCIS (Netherlands)

    Van der Putten, W.H.; Peters, B.A.M.; Van den Berg, R.S.

    1997-01-01

    Three successive emergent macrophytes (Typha latifolia L., Phragmites australis (Cav.) Steudel and Glyceria maxima (Hartman) Holmbly) were each grown in substrates collected from three different zones of shoreline vegetation development (non- vegetated sediment, the interface between T. latifolia an

  9. PIXE analysis of chromium phytoaccumulation by the aquatic macrophytes Eicchornia crassipes

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza-Quinones, F.R. [Department of Chemical Engineering - Postgraduate Program - NBQ, West Parana State University, Rua da Faculdade, 645, Jardim Santa Maria, 85903-000 Toledo, Parana (Brazil)], E-mail: f.espinoza@terra.com.br; Rizzutto, M.A.; Added, N.; Tabacniks, M.H. [Physics Institute, University of Sao Paulo, Rua do Matao s/n, Travessa R 187, 05508-900 Sao Paulo, SP (Brazil); Modenes, A.N.; Palacio, S.M.; Silva, E.A.; Rossi, F.L.; Martin, N.; Szymanski, N. [Department of Chemical Engineering - Postgraduate Program - NBQ, West Parana State University, Rua da Faculdade, 645, Jardim Santa Maria, 85903-000 Toledo, Parana (Brazil)

    2009-04-15

    The uptake of hexavalent chromium in free living floating aquatic macrophytes Eicchornia crassipes cultivated in non-toxic chromium-doped hydroponic solutions is presented. A Cr-uptake bioaccumulation experiment was carried out using healthy macrophytes grown in a temperature controlled greenhouse. Six samples of nutrient media and plants were collected during the 23 day experiment. Roots and leaves were acid digested with the addition of an internal Gallium standard, for thin film sample preparation and quantitative Cr analysis by PIXE method. The Cr{sup 6+} mass uptake by the macrophytes reached up to 70% of the initial concentration, comparable to former results and literature data. The Cr-uptake data were described using a non-structural first order kinetic model. Due to low cost and high removal efficiency, living aquatic macrophytes E. crassipes are a viable biosorbent in an artificial wetland of a water effluent treatment plant.

  10. Nitrogen or phosphorus limitation in lakes and its impact on phytoplankton biomass and submerged macrophyte cover

    DEFF Research Database (Denmark)

    Søndergaard, Martin; Lauridsen, Torben Linding; Johansson, Liselotte Sander

    2017-01-01

    macrophyte cover. We conclude that P is of key importance for the ecological quality of Danish lakes but that increased N concentrations, particularly in shallow lakes with moderate to high TP, may have significantly adverse effects on lake water quality and ecological status in summer.......We used data on nutrients, chlorophyll a (Chla) and submerged macrophyte cover from up to 817 Danish lakes to elucidate seasonal variations in nitrogen (N) and phosphorus (P) concentrations and to study the impact of N or its role in combination with P. In both deep and shallow lakes, we found...... related more strongly to TP than to TN, but at high TP concentrations TN explained more of the variability in Chla than TP. Macrophyte cover tended to decrease at increasing TN when TP was between 0.1 and 0.4 mg/l. At macrophyte cover above 20%, Chla was considerably lower compared with lakes with low...

  11. Response of littoral macrophytes to water level fluctuations in a storage reservoir

    National Research Council Canada - National Science Library

    Krolová, M; Čížková, H; Hejzlar, J; Poláková, S

    2013-01-01

    Lakes and reservoirs that are used for water supply and/or flow regulations have usually poorly developed littoral macrophyte communities, which impairs ecological potential in terms of the EU Water Framework Directive...

  12. Does mechanical disturbance affect the performance and species composition of submerged macrophyte communities?

    Science.gov (United States)

    Zhang, Qian; Xu, Ying-Shou; Huang, Lin; Xue, Wei; Sun, Gong-Qi; Zhang, Ming-Xiang; Yu, Fei-Hai

    2014-01-01

    Submerged macrophyte communities are frequently subjected to disturbance of various frequency and strength. However, there is still little experimental evidence on how mechanical disturbance affects the performance and species composition of such plant communities. In a greenhouse experiment, we constructed wetland communities consisting of five co-occurring clonal submerged macrophyte species (Hydrilla verticillata, Elodea canadensis, Ceratophyllum demersum, Chara fragilis, and Myriophyllum spicatum) and subjected these communities to three mechanical disturbance regimes (no, moderate and strong disturbance). Strong mechanical disturbance greatly decreased overall biomass, number of shoot nodes and total shoot length, and increased species diversity (evenness) of the total community. It also substantially decreased the growth of the most abundant species (H. verticillata), but did not affect growth of the other four species. Our data reveal that strong disturbance can have different effects on different submerged macrophyte species and thus alters the performance and species composition of submerged macrophyte communities. PMID:24811826

  13. Capabilities of Seven Species of Aquatic Macrophytes for Phytoremediation of Pentachlorophenol Contaminated Sediment

    Science.gov (United States)

    Zhao, Liangyuan; Guo, Weijie; Li, Qingyun; Li, Huan; Zhao, Weihua; Cao, Xiaohuan

    2017-01-01

    Sediments are regarded as the ultimate sink of pentachlorophenol(PCP) in aquatic environment, and capabilities of seven species of aquatic macrophytes for remediating PCP contaminated sediment were investigated. Seven species of aquatic macrophytes could significantly accelerate the degradation of PCP in sediments. Among all, canna indica L., Acorus calamus L. and Iris tectorum Maxim. can be used as efficient alternative plants for remediation of PCP contaminated sediment, which attained 98%, 92% and 88% of PCP removal in sediments, respectively. PCP was detected only in root tissues and the uptake was closely related to the root lipid contents of seven plants. The presence of seven aquatic macrophytes significantly increased microbial populations and the activities of dehydrogenase compared with control sediments, indicating that rhizosphere microorganism played important role in the remediation process. In conclusion, seven species of aquatic macrophytes may act as promising tools for the PCP phytoremediation in aquatic environment, especially Canna indica L., Acorus calamus L. and Iris tectorum Maxim.

  14. Long-term allelopathic control of phytoplankton by the submerged macrophyte Elodea nuttallii

    NARCIS (Netherlands)

    Vanderstukken, M.; Declerck, S.A.J.; Decaestecker, E.; Muylaert, K.

    2014-01-01

    Keywords: allelochemicals; chemical ecology; competition; nutrient limitation; shallow lakes Summary 1.It is well known that submerged macrophytes can suppress phytoplankton blooms in lakes and thus promote water quality and biodiversity. One of the possible mechanisms through which submerged

  15. Regulation and role of epiphytic nitrification and denitrification in macrophyte-dominated systems

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, Peder G.

    2000-02-01

    This thesis examines mechanisms regulating bacterial nitrification and denitrification in attached microbial communities on surfaces of aquatic macrophytes. It also evaluates the role of epiphytic nitrification and denitrification for the nitrogen turnover in macrophyte-dominated nutrient-rich freshwater. Epiphytic nitrification is promoted in light and epiphytic denitrification occurs mainly in dark, because the metabolic activity of the aquatic macrophyte and its epiphytes induce in light high and in dark low oxygen concentrations in epiphytic communities. Epiphytic nitrification and denitrification are also affected by the physical and chemical characteristics of the aquatic macrophyte. The spatial distribution of nitrification in emergent macrophyte wetlands is related to the species composition of the emergent vegetation, possibly because of a macrophyte species-related release of organic nitrification inhibitors. Contrasting to nitrifying bacteria, which are lithotrophic, denitrifying bacteria use organic substances as an energy source and are therefore stimulated by the release of organic matter from aquatic macrophytes. Epiphytic communities support more denitrification in nutrient-rich than in nutrient-poor environments. In lakes and ponds, epiphytic denitrification is higher at sheltered locations than at locations exposed to wind-induced water movements or currents. In flowing water, epiphytic denitrification occurs mainly at low oxygen concentrations in the surrounding water. However, because aquatic macrophytes impede water flow and induce low oxygen concentrations in dark, epiphytic denitrification can be present within dense vegetation despite of high oxygen concentrations in the surrounding water. Epiphytic nitrification is almost unaffected by flow conditions, and can occur both in light and in dark. In shallow-water systems such as treatment wetlands, aquatic macrophytes often provide most of the accessible surface area for attached nitrifying and

  16. Haloacetic acids in the aquatic environment. Part I: macrophyte toxicity.

    Science.gov (United States)

    Hanson, Mark L; Solomon, Keith R

    2004-08-01

    Haloacetic acids (HAAs) are contaminants of aquatic ecosystems with numerous sources, both anthropogenic and natural. The toxicity of HAAs to aquatic plants is generally uncharacterized. Laboratory tests were conducted with three macrophytes (Lemna gibba, Myriophyllum sibiricum and Myriophyllum spicatum) to assess the toxicity of five HAAs. Myriophyllum spp. has been proposed as required test species for pesticide registration in North America, but few studies have been conducted under standard test conditions. The HAAs in the present experiments were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). MCA was the most toxic to Myriophyllum spp. with EC50 values ranging from 8 to 12.4 mg/l depending on the endpoint, followed by DCA (EC50 range 62-722.5 mg/l), TCA (EC50 range 49.5-1702.6 mg/l), CDFA (EC50 range 105.3 to >10,000 mg/l) and with TFA (EC50 range 222.1 to 10,000 mg/l) the least toxic. Generally, L. gibba was less sensitive to HAA toxicity than Myriophyllum spp., with the difference in toxicity between them approximately threefold. The range of toxicity within Myriophyllum spp. was normally less than twofold. Statistically, plant length and node number were the most sensitive endpoints as they had the lowest observed coefficients of variation, but they were not the most sensitive to HAA toxicity. Toxicological sensitivity of endpoints varied depending on the measure of effect chosen and the HAA, with morphological endpoints usually an order of magnitude more sensitive than pigments for all plant species. Overall, mass and root measures tended to be the most sensitive indicators of HAA toxicity. The data from this paper were subsequently used in an ecological risk assessment for HAAs and aquatic plants. The assessment found HAAs to be of low risk to aquatic macrophytes and the results are described in the second manuscript of this series.

  17. Experimental Effects of Lime Application on Aquatic Macrophytes: 3. Growth Response Versus Exposure Time

    Science.gov (United States)

    2008-01-01

    ERDC/TN APCRP-EA-17 January 2008 Experimental Effects of Lime Application on Aquatic Macrophytes : 3. Growth Response Versus Exposure Time by William...be effective in both suppressing submersed macrophyte growth and changing species composition (Babin et al. 1992; Chambers et al. 2001; Prepas et al...16 cm height) filled with homogenized sediment (obtained from Eau Galle Reservoir , WI; see James et al. (2005) for a description of sediment

  18. The use of macrophytes for heavy metal pollution control in urban wetlands

    OpenAIRE

    Zhang, Tiantian

    1990-01-01

    A literature survey has been undertaken to identify the role and function of aquatic macrophytes in the removal of contaminants from polluted surface waters. The survey focussed primarily on heavy metals, however nitrate, phosphate and hydrocarbon removal are also discussed and the application of aquatic macrophytes in wastewater treatment systems is also described. The objectives of the research are: To determine heavy metal variations in water, sediment and plant tissues in both fiel...

  19. Banking system trust, bank trust, and bank loyalty

    NARCIS (Netherlands)

    van Esterik-Plasmeijer, P.; van Raaij, W.F.

    2017-01-01

    Purpose The purpose of this paper is to test a model of banking system trust as an antecedent of bank trust and bank loyalty. Six determinants of trust and loyalty are included: competence, stability, integrity, customer orientation, transparency, and value congruence. The study provides insights

  20. Germ banks affect the inference of past demographic events.

    Science.gov (United States)

    Živković, Daniel; Tellier, Aurélien

    2012-11-01

    Continuous progress in empirical population genetics based on the whole-genome polymorphism data requires the theoretical analysis of refined models in order to interpret the evolutionary history of populations with adequate accuracy. Recent studies focus prevalently on the aspects of demography and adaptation, whereas age structure (for example, in plants via the maintenance of seed banks) has attracted less attention. Germ banking, that is, seed or egg dormancy, is a prevalent and important life-history trait in plants and invertebrates, which buffers against environmental variability and modulates species extinction in fragmented habitats. Within this study, we investigate the combined effect of germ banking and time-varying population size on the neutral coalescent and particularly derive the allele frequency spectrum under some simplifying assumptions. We then perform an ABC analysis using two simple demographic scenarios-a population expansion and an instantaneous decline. We demonstrate the appreciable influence of seed banks on the estimation of demographic parameters depending on the germination rate with biases scaled by the square of the germination rate. In the more complex case of a population bottleneck, which comprises an instantaneous decline and an expansion phase, ignoring information on the germination rate denies reliable estimates of the bottleneck parameters via the allelic spectrum. In particular, when seeds remain in the bank over several generations, recent expansions may remain invisible in the frequency spectrum, whereas ancient declines leave signatures much longer than in the absence of seed bank.

  1. A preliminary evaluation of lake morphometric traits influence on the maximum growing depth of macrophytes

    Directory of Open Access Journals (Sweden)

    Mattia M. Azzella

    2014-03-01

    Full Text Available Underwater light regime is widely considered the principal determinant of aquatic plant depth distribution. The majority of previous studies dealing with macrophytes in lakes have singled out Secchi disk transparency (SD values as the key empirical proxy to explain the maximum depth of macrophyte colonization (Zc. Few studies have investigated the role played by lake morphometry in structuring macrophyte beds. Using a balanced dataset including 20 Italian lakes (10 shallow and 10 deep lakes, we analysed transparency and lake morphometric traits to investigate their possible effects on Zc. Our results demonstrate that lake area plays a significant role, and confirm a direct influence of SD values on Zc. Considering lakes with an equal degree of transparency, smaller lakes may yield a lower Zc than larger ones. Morphology has a great influence on lake ecological characteristics especially on water thermal conditions and mixing depth. Based on our data, we argue that the thermal stratification plays a non negligible role in explaining macrophytes zonation, due to its influence on macrophytes life cycles and phytoplankton vertical distribution. Therefore, the present data suggest the need to enhance and refine our knowledge about the relationship between aquatic plants distribution and lake thermal conditions to better model the response of macrophytes to climate change and eutrophication.

  2. The study of aquatic macrophytes in Neotropics: a scientometrical view of the main trends and gaps.

    Science.gov (United States)

    Padial, A A; Bini, L M; Thomaz, S M

    2008-11-01

    Aquatic macrophytes comprises a diverse group of organisms including angiosperms, ferns, mosses, liverworts and some macroalgae that occur in seasonally or permanently wet environments. Among other implications, aquatic macrophytes are highly productive and with an important structuring role on aquatic environments. Ecological studies involving aquatic plants substantially increased in the last years. However, a precise view of researches devoted to aquatic macrophytes in Neotropics is necessary to reach a reliable evaluation of the scientific production. In the current study, we performed a scientometrics analysis of the scientific production devoted to Neotropical macrophytes in an attempt to find the main trends and gaps of researches concerning this group. The publication devoted to macrophytes in Neotropics increased conspicuously in the last two decades. Brazil, Argentina, Mexico and Chile were the most productive among Neotropical countries. Our analyses showed that the studies dealt mostly with the influences of aquatic macrophytes on organisms and abiotic features. Studies with a predictive approach or aiming to test ecological hypothesis are scarce. In addition, researches aiming to describe unknown species are still necessary. This is essential to support conservation efforts and to subsidize further investigations testing ecological hypotheses.

  3. Emergent Macrophytes Support Zooplankton in a Shallow Tropical Lake: A Basis for Wetland Conservation.

    Science.gov (United States)

    Gebrehiwot, Mesfin; Kifle, Demeke; Triest, Ludwig

    2017-09-08

    Understanding the biodiversity value of littoral zones of lakes is a priority for aquatic biodiversity conservation. However, less emphasis has been given to the littoral part of tropical African lakes, with many of the previous researches focusing only on the open water side. The aim of the present study was, therefore, to investigate the impact of the littoral zone of a shallow freshwater tropical lake (Ziway, Ethiopia), dominated by two emergent macrophytes, on zooplankton community structure. We hypothesized that the wetland vegetation serves as a preferred microhabitat for zooplankton communities. A lake with substantial coverage of emergent macrophytes was monitored monthly from January to August, 2016. The monitoring included the measurements of physical, chemical, and biological parameters. Sampling sites were selected to represent areas of the macrophyte vegetation (Typha latifolia and Phragmites australis) and the open water part of the lake. Sites with macrophyte vegetation were found to be the home of more dense and diverse zooplankton community. However, during the period of high vegetation loss, the density of crustacean zooplankton showed significant reduction within the patches of macrophytes. From biodiversity conservation perspective, it was concluded that the preservation of such small areas of macrophytes covering the littoral zone of lakes could be as important as protecting the whole lake. However, the rapid degradation of wetland vegetation by human activities is a real threat to the lake ecosystem. In the not-too-far future, it could displace and evict riparian vegetation and the biota it supports.

  4. Responses of bacterial community structure and denitrifying bacteria in biofilm to submerged macrophytes and nitrate

    Science.gov (United States)

    Zhang, Songhe; Pang, Si; Wang, Peifang; Wang, Chao; Guo, Chuan; Addo, Felix Gyawu; Li, Yi

    2016-10-01

    Submerged macrophytes play important roles in constructed wetlands and natural water bodies, as these organisms remove nutrients and provide large surfaces for biofilms, which are beneficial for nitrogen removal, particularly from submerged macrophyte-dominated water columns. However, information on the responses of biofilms to submerged macrophytes and nitrogen molecules is limited. In the present study, bacterial community structure and denitrifiers were investigated in biofilms on the leaves of four submerged macrophytes and artificial plants exposed to two nitrate concentrations. The biofilm cells were evenly distributed on artificial plants but appeared in microcolonies on the surfaces of submerged macrophytes. Proteobacteria was the most abundant phylum in all samples, accounting for 27.3-64.8% of the high-quality bacterial reads, followed by Chloroflexi (3.7-25.4%), Firmicutes (3.0-20.1%), Acidobacteria (2.7-15.7%), Actinobacteria (2.2-8.7%), Bacteroidetes (0.5-9.7%), and Verrucomicrobia (2.4-5.2%). Cluster analysis showed that bacterial community structure can be significantly different on macrophytes versus from those on artificial plants. Redundancy analysis showed that electrical conductivity and nitrate concentration were positively correlated with Shannon index and operational taxonomic unit (OTU) richness (log10 transformed) but somewhat negatively correlated with microbial density. The relative abundances of five denitrifying genes were positively correlated with nitrate concentration and electrical conductivity but negatively correlated with dissolved oxygen.

  5. Growth rate, protein:RNA ratio and stoichiometric homeostasis of submerged macrophytes under eutrophication stress

    Directory of Open Access Journals (Sweden)

    Xing W.

    2016-01-01

    Full Text Available Growth rate hypothesis (GRH and stoichiometric homeostasis of photoautotrophs have always been questioned. However, little is known about GRH and stoichiometric homeostasis of aquatic plants, especially submerged macrophytes. Therefore, we aim to test the GRH and explore stoichiometric homeostasis of four freshwater submerged macrophytes under eutrophication stress. At the single species level and the multi-species level, N:P ratios of Potamogeton maackianus, Myriophyllum spicatum, Vallisneria natans and Ceratophyllum demersum had no consistent trends with growth rates. However, protein:RNA ratios of P. maackianus, M. spicatum and V. natans all correlated negatively with growth rates, demonstrating GRH can apply to freshwater submerged macrophytes, even though they are threatening by eutrophication stress. Protein:RNA ratios positively correlated with N:P ratios in culture media and tissues in submerged macrophytes except in P. maackianus (30d, suggesting effects of varying N:P ratios in culture media on protein:RNA ratios are basically in concert with tissue N:P ratios under short-time eutrophication stress. Stoichiometric homeostasis coefficients (HN:P indicated submerged macrophytes have weak homeostasis. Stoichiometric homeostasis of V. natans was stronger than those of P. maackianus, M. spicatum and C. demersum. The differences in GRH and homeostasis of the four submerged macrophytes may be due to species traits.

  6. Banco de sementes de remanescentes naturais e de áreas reflorestadas em uma várzea do Rio Mogi-Guaçu - SP Seed bank of natural forest remainders and reforestation areas in a Mogi-Guaçu river floodplain, Luiz Antônio County, São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Assíria Maria Ferreira da Nóbrega

    2009-06-01

    Full Text Available Este estudo avaliou qualitativa e quantitativamente o banco de sementes de dois remanescentes florestais, de um povoamento de Eucalyptus robusta e de três áreas de reflorestamento com espécies nativas, localizados em uma várzea do rio Mogi-Guaçu, Luiz Antônio (21°31´S e 47°55´W, Estado de São Paulo, Brasil. Foram usadas 12 parcelas de 10 x 10 m distribuídas sistematicamente em cada área de estudo. Em cada parcela foram distribuídas aleatoriamente quatro subparcelas de 0,5 m x 0,5 m. Duas subparcelas foram usadas para coletar a serapilheira e duas para coletar o solo a 0-5 cm de profundidade. A amostragem foi realizada em setembro de 2001, nos remanescentes naturais e no povoamento de eucalipto e, em setembro de 2002, nas áreas reflorestadas. As amostras foram acondicionadas em vasos de plástico e incubadas com irrigações periódicas para a germinação das sementes por um período de sete meses, em dois ambientes de casa de vegetação: um a 100% de luz solar e outro sob tela com 70% de redução de luz solar. Na composição do banco de sementes de todas as áreas amostradas, houve predominância de espécies pioneiras dos primeiros estádios de sucessão. As espécies arbóreas mais importantes foram Aloysia virgata e Cecropia hololeuca. Os reflorestamentos com espécies nativas proporcionaram um banco de sementes com maior diversidade de espécies arbóreas nativas do que o povoamento de eucalipto. Este estudo indicou que a similaridade entre as florestas plantadas e as nativas deverá aumentar ao longo do tempo.The objective of this study was to evaluate qualitative and quantitatively the seed bank of two natural forest remainders, one Eucalyptus robusta plantation and three reforestation areas with native species, located in a riparian area of Mogi-Guaçu River floodplain, in Luiz Antonio County (21°31´S and 47°55´W, São Paulo State, Brazil. The evaluation was carried out in 12 plots of 10 x 10 m systematically

  7. Green banking

    Directory of Open Access Journals (Sweden)

    Maja Drobnjaković

    2013-06-01

    Full Text Available There is an urgent need to march towards “low - carbon economy”. Global challenges of diminishing fossil fuel reserves, climate change, environmental management and finite natural resources serving an expanding world population - these reasons mean that urgent action is required to transition to solutions which minimize environmental impact and are sustainable. We are at the start of the low - carbon revolution and those that have started on their low - carbon journey already are seeing benefits such as new markets and customers, improved economic, social and environmental performance, and reduced bills and risks. Green investment banks offer alternative financial services: green car loans, energy efficiency mortgages, alternative energy venture capital, eco - savings deposits and green credit cards. These items represent innovative financial products.

  8. Banking Reform in Georgia

    OpenAIRE

    Mercan, Metin

    2006-01-01

    Georgia's banking system restructure began in 1991 when Soviet Union collopsed.This paper tries to compare and constract the performance of banks and banking system between 1999 and 2004 with banks in other transition countries. Although Georgia banking system showed a long processing in banking sector, it is still lags behind other transition countries Central and Eastern Europe. Neverthless.An efficient financial institution and performance will not come without further economic development...

  9. Banking governance: New Approaches

    Directory of Open Access Journals (Sweden)

    Victor Mihăiţă Duţă

    2016-11-01

    Full Text Available Banks are companies like any other. However, banks are distinguished by certain intrinsic characteristics of companies that have a different impact on the motivation of stakeholders. Among these features, we mention:partnership and shareholders governance agreements; banks are heavily regulated companies; banking assets is the main source of haze banking and information asymmetry; between the bank and depositors there is a problem of moral hazard.

  10. ROMANIAN BANKS LIQUIDITY MANAGEMENT

    Directory of Open Access Journals (Sweden)

    BATRANCEA MARIA

    2013-07-01

    Full Text Available Most transactions or financial commitments have implications for a bank liquidity. Transactions are particularly vulnerable to liquidity problems at a specific institution. Therefore, one can deduce the importance of the correct calculation and liquidity indicator, not only for the bank concerned, but especially for NBR uses that bank risk management tool. That is why the authors took into consideration a sample of banks in Romania to show to what extent the banking crisis has influenced the development banks.

  11. A MODIS-Based Novel Method to Distinguish Surface Cyanobacterial Scums and Aquatic Macrophytes in Lake Taihu

    National Research Council Canada - National Science Library

    Liang, Qichun; Zhang, Yuchao; Ma, Ronghua; Loiselle, Steven; Li, Jing; Hu, Minqi

    2017-01-01

      Satellite remote sensing can be an effective alternative for mapping cyanobacterial scums and aquatic macrophyte distribution over large areas compared with traditional ship's site-specific samplings...

  12. Electronic Banking And Bank Performance In Nigeria

    African Journals Online (AJOL)

    2013-03-01

    Mar 1, 2013 ... However, the revolution in the banking industry in Nigeria started .... with the banks overall strategic and business plans, and adequate expertise should be employed to operate and ..... 2010 from http://www.bis./pub/bcbs/pdf.

  13. Spatial and temporal dynamics of macrophyte cover in a large regulated river.

    Science.gov (United States)

    Tena, A; Vericat, D; Gonzalo, L E; Batalla, R J

    2016-11-24

    The River Ebro basin is extensively dammed. Dams alter the geomorphological functioning of the river by altering its flow regime (e.g. reducing mean and maximum discharges), increasing bed stability (armouring) and decreasing turbidity (water clarity). These effects, together with an increase in nutrient concentrations and water temperature, have generated optimal conditions for the proliferation of aquatic macrophytes. In this paper, we analyse the temporal and spatial changes of macrophyte cover in the lowermost Ebro through a series of field campaigns carried out between 2009 and 2010. Special attention was paid to the spatial distribution of macrophytes in relation to flow hydraulics, channel geometry and bed sedimentology. Temporal changes in macrophyte cover were analysed in relation to the frequency and magnitude of both natural floods and flushing flows (artificial flow releases from dams with generally a magnitude that equates around a2-year flood in the river). Spatially, the proportion of macrophytes along the reaches showed a variable pattern, with a succession of areas with both high and low plant density, coinciding with the alternation of riffles and pools in the channel. The highest values of plant cover (>65%) occurred in riffles and in transition to riffle areas, while the lowest densities (1% or almost negligible) were observed in pools and transition to pool areas. Water depth and the grain-size distribution of the riverbed materials (i.e. D84), are found to be the main factors controlling the degree of plant cover in the lower Ebro. Temporally, the macrophyte proportion varied during the hydrological year, with a clear increment from late spring to early autumn (i.e. vegetation cover reached 40%, on average, of the channel surface). Macrophyte coverage decreases immediately following a flushing flow but in the long term, vegetation re-occupied the area again, even slightly increasing in some sections; overall, the mean percentage of macrophyte

  14. Seed quality in informal seed systems

    OpenAIRE

    Biemond, P.C.

    2013-01-01

    Keywords:     informal seed systems, seed recycling, seed quality, germination, seed pathology, seed health, seed-borne diseases, mycotoxigenic fungi, Fusarium verticillioides, mycotoxins, Vigna unguiculata, Zea mays, Nigeria.   Seed is a crucial input for agricultural production. Approximately 80% of the smallholder farmers in Africa depend for their seed on the informal seed system, consisting of farmers involved in selection, production and dissemination of seed. The la...

  15. Internet Banking System Prototype

    CERN Document Server

    Alnaqeib, Rami; Jalab, Hamid A; Zaidan, M A; Hmood, Ali K

    2010-01-01

    Internet Banking System refers to systems that enable bank customers to access accounts and general information on bank products and services through a personal computer or other intelligent device. Internet banking products and services can include detailed account information for corporate customers as well as account summery and transfer money. Ultimately, the products and services obtained through Internet Banking may mirror products and services offered through other bank delivery channels. In this paper, Internet Banking System Prototype has been proposed in order to illustrate the services which is provided by the Bank online services.

  16. Storage in cerrado soil and germination of Psychotria vellosiana (Rubiaceae seeds

    Directory of Open Access Journals (Sweden)

    C. G. Araújo

    Full Text Available The regeneration of plant communities from seed depends, to a large extent, on the capacity of the seed remaining viable in the soil. The viability and germination of artificially buried Psychotria vellosiana seeds in cerrado soil were studied, with the purpose of discovering some physio-ecological aspects of dispersed seeds and evaluating their potential to constitute a soil seed bank. Seed samples were placed in nylon envelopes and buried in the soil of a Cerrado reserve at two different depths and sites. Buried seeds were retrieved periodically and tested for germination along with dry-stored seeds. In general, there was a reduction in seed germination with storage time, both in soil and dry stored conditions, and in some assays exhumed seeds germinated faster than dry stored ones. In general the soil storage favoured seed viability of ungerminated seeds as compared to dry stored ones, with the seeds remaining partially viable after 10 months of storage. The lack of germination of viable seeds suggests that seeds showed true dormancy and/or required an extended time to germinate. It was observed that some seeds had germinated while buried and such in situ germination tended to increase with rainfall. The water availability in the soil might be a limiting factor for successful germination of P. vellosiana in the field, and the seeds may constitute a persistent soil seed bank in the cerrado as dispersed seeds remain viable in the soil until the following period of seed dispersal.

  17. E-BANKING- MODERN BANKING SERVICES

    Directory of Open Access Journals (Sweden)

    MIRANDA PETRONELLA VLAD

    2009-05-01

    Full Text Available E-banking is the first of those banking services that really economize time, because it allows to the user to accomplish from behind the computer many operations in the bank account, represents the computational solution that allows to the holder to have

  18. Submerged macrophyte biomass distribution in the shallow saline lake Fuente de Piedra (Spain as function of environmental variables

    Directory of Open Access Journals (Sweden)

    Conde-Álvarez, Rafael M.

    2012-06-01

    Full Text Available Aquatic macrophyte biomass, diaspore bank distribution and their relationship to spatial variability of depth, nutrients (nitrite, nitrate, ammonium and soluble reactive phosphorus as well as sediment granulometry in an athalassohaline lake have been studied during one wet hydrological year. The results indicate that species growing in the lake show different spatial distribution patterns throughout the lake. Indirect gradient analysis (canonical analysis results showed a first axis defined as a function of Ulva flexuosa Wulfen biomass which is, in turn, positively correlated with interstitial ammonium and Soluble Reactive Phosphorus (SRP. The second axis was mainly established due to Lamprothamnium papulosum (Wallr. J. Groves biomass which correlated positively to depth and negatively to interstitial ammonium and SRP. These results revealed a NESW eutrophic gradient allowing the U. Flexuosa biomass proliferation. This phenomenon could increase the shadow effect over the rest of the macrophytes inhabiting this shallow lake. Moreover, the eutrophic harmful effect on the macrophyte physiology and over the diaspore bank could have important consequences in the survival of such important populations. The results reported in this study show the need for studies as the base to select sampling points for monitoring this wetland.

    La distribución de la biomasa de los macrófitos acuáticos y de su banco de semillas y oogonios ha sido investigada en relación a la profundidad, los nutrientes (nitrito, nitrato, amonio y fósforo soluble reactivo y la granulometría del sedimento durante un año hidrológico húmedo. Los resultados muestran patrones de distribución diferentes en las distintas especies. Los resultados del análisis canónico basado en análisis de gradiente indirecto muestran un primer eje definido en función de la biomasa de U. Flexuosa, Wulfen que, a su vez, está positivamente correlacionada con el

  19. Temporal trends and effects of diversity on occurrence of exotic macrophytes in a large reservoir

    Science.gov (United States)

    Thomaz, Sidinei Magela; Carvalho, Priscilla; Mormul, Roger Paulo; Ferreira, Fernando Alves; Silveira, Márcio José; Michelan, Thaísa Sala

    2009-09-01

    Two exotic invasive macrophyte species (the emergent Urochloa subquadripara - tenner-grass - and the submersed Hydrilla verticillata - hydrilla) were investigated in a large sub-tropical reservoir. We analyzed their occurrences over an extended period and tested the hypothesis that macrophyte richness decreases their invasibility. The alternative hypothesis that the occurrence of these exotics is affected by fetch and underwater radiation (important determinants of macrophyte assemblage composition in this reservoir) was also tested. Incidence data (presence/absence) was obtained over 9.5 years at 235 stations. Logistic regression was applied to test whether the likelihood of occurrence of these two species was affected by macrophyte richness, fetch or underwater radiation. Tenner-grass was recorded at a high frequency and quickly recovered from disturbances caused by water drawdown. In contrast, H. verticillata was first recorded in 3 sites in January 2007, but it spread quickly, reaching 30.5% of the sites 19 months later. The main channel of the Paraná River was the main source of propagules for this species. The likelihood of occurrence of tenner-grass was positively affected by macrophyte richness but negatively affected by fetch. Thus, wave disturbance is probably more important than diversity in preventing invasion by this species. Hydrilla, by contrast, was negatively affected by macrophyte richness and positively affected by fetch and underwater radiation. Although this result might indicate that macrophyte diversity prevents hydrilla invasion, this is probably not true because hydrilla colonized deeper sites where few species of plant exist. Resistance to disturbances caused by water drawdown (tenner-grass) and waves (hydrilla) as well as persistency of tenner-grass and fast spread of hydrilla make these exotic species a cause for concern because of their potential impacts on water uses and maintenance of diversity.

  20. Simple relationships to predict attributes of fish assemblages in patches of submerged macrophytes

    Directory of Open Access Journals (Sweden)

    Fernando Mayer Pelicice

    Full Text Available Submerged macrophytes play an important role in structuring habitats and, therefore, in determining patterns of aquatic biodiversity. Because these plants are widespread in shallow areas of many Neotropical reservoirs, the present work investigated if variables related to habitat structure, measured in patches of submerged macrophytes (Egeria densa and E. najas, can be used to predict fish assemblage attributes (fish density and species richness. Based on patch characteristics at fine spatial extents (macrophyte patches within reservoir arms, we considered plant biomass, volume and proportional volume (i.e. percentage of macrophyte volume in the water column as potential predictors. Fish and macrophytes were sampled with a 1-m² throw trap in littoral habitats of Rosana Reservoir, Paranapanema River, and simple correlation analyses were performed. Fish richness and abundance were highly correlated with all variables (R = 0.53 to 0.90, a relationship consistently observed in all sites. When compared to biomass, plant volume and proportional volume did not yield stronger correlations. We observed stronger correlations when E. densa and E. najas patches were analyzed separately (mono-specificity, probably because particular effects of each macrophyte on habitat structuring were removed (e.g. unnoticed morphological differences or unknown effects on habitat quality. The high R values observed in all pairwise relationships are uncommon in ecological studies, highlighting the predictive potential of variables related to habitat structure. These results suggest that, at small spatial extents, macrophyte biomass may represent an interesting predictor of fish density and richness in reservoirs with extensive colonization of submerged plants.

  1. Monitoring the effects of floods on submerged macrophytes in a large river.

    Science.gov (United States)

    Ibáñez, Carles; Caiola, Nuno; Rovira, Albert; Real, Montserrat

    2012-12-01

    The lower Ebro River (Catalonia, Spain) has recently undergone a regime shift from a phytoplankton to a macrophyte-dominated system. Macrophytes started to spread at the end of the 1990s and since 2002 artificial floods (flushing flows) of short duration (1-2 days) are released from the Riba-roja dam once or twice a year in order to reduce macrophyte density. The aim of this study was to analyse the spatiotemporal trends of the submerged macrophytes in two stretches of the lower Ebro River using high-resolution hydroacoustic methods, in order to elucidate the effects of artificial floods and natural floods on its distribution and abundance. Results showed that the mean cover in the two studied stretches (Móra and Ginestar) was not reduced after a flushing flow (from 36.59% to 55.85% in Móra, and from 21.18% to 21.05% in Ginestar), but it was greatly reduced after the natural flood (down to 9.79% in Móra and 2.04% in Ginestar); surprisingly the cover increased in Móra after the artificial flood. In order to increase the efficiency of floods in controlling macrophyte spreading, the magnitude and frequency of them should largely increase, as well as the suspended sediment load, approaching as much as possible to the original flood pattern before dam construction. Hydroacoustic methods combined with geostatistics and interpolation in GIS can accurately monitor spatiotemporal trends of submerged macrophytes in large rivers. This is the first article to apply this monitoring system to submerged macrophytes in rivers. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Analyses of species composition and diversity of weed seed bank of main crop fields in Jiangsu Province and its correlation with environmental factors%江苏省主要农田杂草种子库物种组成和多样性及其与环境因子的相关性分析

    Institute of Scientific and Technical Information of China (English)

    章超斌; 马波; 强胜

    2012-01-01

    D指数随土层深度增加而降低、E指数逐渐升高,水田各土层的物种多样性指数则无明显变化趋势.第1种类排序轴与淹水天数负相关性最高(R=-0.8143),第2种类排序轴与年降水量和经度也有较高的负相关性;相关性分析和CCA分析结果均表明淹水天数是影响杂草种子库群落构成的最大因素.通过二维排序可将31个样点分为旱田和水田2大类,旱田可划分为长期旱连作和水旱轮作2个亚类;水田可划分为淮河以北地区和淮河以南长江流域地区2个亚类.研究结果说明:杂草种子库潜群落优势种与地上部农田杂草显群落优势种具有一致性,通过土壤杂草种子库的研究可以预测地上杂草的发生和危害情况.%The species composition and diversity of weed seed bank of 0-15 cm soil layer in 31 sample sites of main crop fields (including upland and paddy fields) in Jiangsu Province were investigated by water washing-microscopic examination method. And correlation between species in weed seed bank and environmental factors (including waterlogging days, organic matter content and pH in soil, annual precipitation, annual mean temperature, latitude and longitude of sites) was analyzed by canonical correspondence analysis ( CCA) , and scatter diagrams of CCA two-dimensional ordination about sites-and species- environment factors were also drawn. The investigation results show that weed seeds of 54 species (41 and 45 species respectively in upland and paddy fields) belonging to 15 families are detected in weed seed bank of 31 sample sites, in which, common weed species are in the majority but dominant species are various in upland and paddy fields. The common dominant species are Mazus japonicus (Thunb.) Kuntze, Cyperus difformis L., Ammannia baccifera L., Leptochloa chinensis ( L.) Nees, Polypogon fugax Nees ex Steud. And Malachium aquaticum ( L.) Fries, etc., and number of weed species in Gramineae and Cyperaceae are the most

  3. effectiveness of community based seed multiplication in enhancing ...

    African Journals Online (AJOL)

    ACSS

    driven CBSM and factors influencing farmers' access to improved bean seed. The study was conducted ..... knowledge of improved bean spacing, time for weeding ..... M.Sc. Thesis. Hawassa ... bank: An experience of western Nepal. Journal of ...

  4. 基于正交试验设计的土壤种子库萌发影响因素优化研究%Research on the Optimization in the Influence factors on the Germination of Soil Seed Bank Based on Orthogonal Test

    Institute of Scientific and Technical Information of China (English)

    赵娜; 贺梦璇; 李洪远; 莫训强

    2016-01-01

    The soil seed bank (SSB) is defined as the collection of viable seeds present in the soil and the forest litter layer of the soil surface, which can serve as the vegetation natural regeneration. Three factors (the topsoil thickness, the covering thickness and the number of entraining arbor seeds) were selected to set orthogonal tests in the study. Based on the characteristic analysis of soil seed bank, vegetation restoration assessment was carried out by the methods of range analysis, principal component analysis, indicator system analysis were used . The results showed that: (1) Compared with blank conditions, the species richness and density of SSB significantly increased in the orthogonal tests . Among them, the total number of seed germination in the orthogonal test was 3519 plants , which was about 3.04 times of the blank condition), and the number of species reached to 39 species, which was about 1.22 times of the blank conditions; (2) The topsoil thickness was the most important factor in the three factors, and the effect wasn’t obvious by adding arbor seeds; (3) The three evaluation methods on the basis was available for evaluating the effect on seed germinating of SSB with their disadvantages,, and the combination of the three methods enhanced the rationality of evaluation results. In the analysis, the 8th plot (A3B2C1) had the best effect of seed germination, which can provide significant reference for vegetation recovery from soil seed bank. The plot was designed with the top soil thickness was 5 cm, the covering thickness was 3 cm, and the number of adding seeds was 100 ind·m-2.%土壤种子库(Soil Seed Bank)是土壤及土壤表面落叶层中所有具有生命力的种子的总和,是植被天然更新的种源贮备库。选取表土铺设厚度、覆盖物厚度、引入乔木种子数量3个因素设置正交试验,分析正交试验后土壤种子库的特征,采用极差分析法、主成分分析法、指标体系法对不同方

  5. Ecological correlates of seed persistence in soil in the north-west European flora

    NARCIS (Netherlands)

    Thompson, K; Bakker, JP; Bekker, RM; Hodgson, JG

    1998-01-01

    I Using the data in a recently published seed bank database for north-west Europe, we describe how a species' seed bank behaviour can be characterized by a single 'longevity index', and investigate how representative the information in the database is of the north-west European flora. We also test t

  6. Impacts of aquatic macrophytes configuration modes on water quality.

    Science.gov (United States)

    Liu, Jiakai; Liu, Jinglan; Zhang, Rong; Zou, Yuqi; Wang, Huihui; Zhang, Zhenming

    2014-01-01

    Constructed wetland technology is regarded as an important ecological restoration technology and used widely in sewage disposal. In order to give them a wider scope of application and to improve their performance in water restoration, the current experiment was designed. Four aquatic macrophytes (dwarf cattail (TM), yellow-flowered iris (WI), water shallot (ST) and watermifoil (MS)) were picked and planted in artificial floating islands (AFIs) in different configurations (TM + WI, ST + MS and TM + WI + MS) and two patterns, radiation pattern (RP) and annular pattern (AP), for a 60-day experiment. Then, water quality and growth were monitored every 10 days. The results indicate that the different configurations performed diversely on waste water purification. First, a composite plant configuration removed more pollutant than a single one with the same total increment of biomass. Second, the plant configuration of MS + ST was most effective in total nitrogen (TN), total phosphorus (TP) or PO4(3-) removal, and TM + IW + MS was good at chemical oxygen demand (COD) and NO3(-) removal. However, different patterns comprised from the same species had a certain effect on absorption of pollutants. Generally speaking, plant configurations with a RP were better than an AP in purification. Accordingly, these provided the methods for the pollution wetland restoration.

  7. Integration of geographic information systems and logistic multiple regression for aquatic macrophyte modeling

    Energy Technology Data Exchange (ETDEWEB)

    Narumalani, S. [Nebraska Univ., Lincoln, NE (United States). Dept. of Geography; Jensen, J.R.; Althausen, J.D.; Burkhalter, S. [South Carolina Univ., Columbia, SC (United States). Dept. of Geography; Mackey, H.E. Jr. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1994-06-01

    Since aquatic macrophytes have an important influence on the physical and chemical processes of an ecosystem while simultaneously affecting human activity, it is imperative that they be inventoried and managed wisely. However, mapping wetlands can be a major challenge because they are found in diverse geographic areas ranging from small tributary streams, to shrub or scrub and marsh communities, to open water lacustrian environments. In addition, the type and spatial distribution of wetlands can change dramatically from season to season, especially when nonpersistent species are present. This research, focuses on developing a model for predicting the future growth and distribution of aquatic macrophytes. This model will use a geographic information system (GIS) to analyze some of the biophysical variables that affect aquatic macrophyte growth and distribution. The data will provide scientists information on the future spatial growth and distribution of aquatic macrophytes. This study focuses on the Savannah River Site Par Pond (1,000 ha) and L Lake (400 ha) these are two cooling ponds that have received thermal effluent from nuclear reactor operations. Par Pond was constructed in 1958, and natural invasion of wetland has occurred over its 35-year history, with much of the shoreline having developed extensive beds of persistent and non-persistent aquatic macrophytes.

  8. Vegetative Propagule Pressure and Water Depth Affect Biomass and Evenness of Submerged Macrophyte Communities.

    Science.gov (United States)

    Li, Hong-Li; Wang, Yong-Yang; Zhang, Qian; Wang, Pu; Zhang, Ming-Xiang; Yu, Fei-Hai

    2015-01-01

    Vegetative propagule pressure may affect the establishment and structure of aquatic plant communities that are commonly dominated by plants capable of clonal growth. We experimentally constructed aquatic communities consisting of four submerged macrophytes (Hydrilla verticillata, Ceratophyllum demersum, Elodea nuttallii and Myriophyllum spicatum) with three levels of vegetative propagule pressure (4, 8 and 16 shoot fragments for communities in each pot) and two levels of water depth (30 cm and 70 cm). Increasing vegetative propagule pressure and decreasing water level significantly increased the growth of the submerged macrophyte communities, suggesting that propagule pressure and water depth should be considered when utilizing vegetative propagules to re-establish submerged macrophyte communities in degraded aquatic ecosystems. However, increasing vegetative propagule pressure and decreasing water level significantly decreased evenness of the submerged macrophyte communities because they markedly increased the dominance of H. verticillata and E. nuttallii, but had little impact on that of C. demersum and M. spicatum. Thus, effects of vegetative propagule pressure and water depth are species-specific and increasing vegetative propagule pressure under lower water level can facilitate the establishment success of submerged macrophyte communities.

  9. Towards Deriving Renewable Energy from Aquatic Macrophytes Polluting Water Bodies in Niger Delta Region of Nigeria

    Directory of Open Access Journals (Sweden)

    Badmus Abdurrahman Adeleye

    2013-01-01

    Full Text Available This study was performed to derive methane rich biogas from biomass of harvested water hyacinth polluting water bodies in selected rivers of the Niger delta region of Nigeria. Field visits were undertaken on selected rivers in the Niger Delta region in which aquatic macrophytes were collected and inventorized. Also different types of aquatic macrophytes were surveyed. Control by harvesting macrophytes and deriving energy (methane-rich biogas from biomass of one (water hyacinth was successfully carried out in this study. An initial test was conducted to evaluate methane rich biogas production from water hyacinth collected from the wild. After a successful production of combustible biogas, laboratory experiments aimed at generating biogas from harvested biomass of aquatic mycrophyte (water hyacinth cultivated under eutrophic and oligotrophic conditions were undertaken in the laboratory. The result of the study showed highest biogas yield of 22 L over a 40 day retention time for water hyacinth raised under eutrophic conditions. Biogas yield for water hyacinth raised under oligotrophic conditions recorded the highest yield of 53L over an 11 day retention time. The conversion of the biomass of harvested aquatic macrophyte (water hyacinth from the Niger Delta into renewable energy, that is combustible biogas, demonstrated an inevitable option for the control and management of environmental pollution associated with aquatic macrophytes and their usability for poverty alleviation in the Niger Delta region of Nigeria.

  10. Genetic and nutritional characterization of some macrophytes, inhabiting the Bardawil Lagoon, Sinai, Egypt

    Directory of Open Access Journals (Sweden)

    Hosam E. Elsaied

    2015-12-01

    Full Text Available The ecological and economical significances of macrophytes, inhabiting the Mediterranean Lagoon, Bardawil, northern Sinai, Egypt, are still ambiguous, due to lack of knowledge. This study focused on genetic and nutritional characterization of three dominant macrophyte species at Bardawil Lagoon. Genetic identifications were done through genomic DNA extraction, followed by PCR amplifications and sequencing of 18S rRNA genes of the studied species. Phylogenetic analyses indicated that two of the recorded species showed homologies with the seagrass species, Posidonia oceanica and Halophila ovalis, with nucleotide identities 94.5% and 96.8%, respectively. The third species showed a unique phylogenetic lineage, representing nucleotide identity average, 86.5%, among the brown seaweeds, Heterokontophyta. Nutritional analyses indicated that the recorded seaweed-like macrophyte had the highest recommended nutritional contents, crude protein, 24.67%, with a total amino acid composition of 6.64 g/100 g protein, and carbohydrate, 38.16%, besides a calorific value of 3.063 K cal/g, among the studied macrophytes. To the best of our knowledge, this is the first attempt to characterize macrophyte community in Bardawil Lagoon, using both genetic and biochemical approaches.

  11. Management of fresh water weeds (macrophytes) by vermicomposting using Eisenia fetida.

    Science.gov (United States)

    Najar, Ishtiyaq Ahmed; Khan, Anisa B

    2013-09-01

    In the present study, potential of Eisenia fetida to recycle the different types of fresh water weeds (macrophytes) used as substrate in different reactors (Azolla pinnata reactor, Trapa natans reactor, Ceratophyllum demersum reactor, free-floating macrophytes mixture reactor, and submerged macrophytes mixture reactor) during 2 months experiment is investigated. E. fetida showed significant variation in number and weight among the reactors and during the different fortnights (P weeds) into three clusters-poor vermicompost substrates, moderate vermicompost substrate, and excellent vermicompost substrate. Two principal components (PCs) have been identified by factor analysis with a cumulative variance of 90.43 %. PC1 accounts for 47.17 % of the total variance represents "reproduction factor" and PC2 explaining 43.26 % variance representing "growth factor." Thus, the nature of macrophyte affects the growth and reproduction pattern of E. fetida among the different reactors, further the addition of A. pinnata in other macrophytes reactors can improve their recycling by E. fetida.

  12. The Chinese Banking System

    OpenAIRE

    2012-01-01

    The Chinese banking system is critical to the functioning of the Chinese economy, being the main conduit through which savings are allocated to investment opportunities. Banking activity in China has grown rapidly over the past decade in association with the expansion of the Chinese economy, and the Chinese banking system now includes some of the world’s largest banks. Chinese banks have become more commercially orientated over this period, although the Chinese Government retains considerable...

  13. Predicting Small Bank Failure

    OpenAIRE

    Heyliger, Wilton E.; Don P. Holdren

    1991-01-01

    There are many studies of bank performance and bank failure in the literature. Most of these studies used banking ratios as variables in their models without giving consideration to their appropriateness, nor was much consideration given to the stability of those ratios through time and across asset size. Many studies also failed to recognize that bank structure may differ by asset size. This study evaluates a large number of banking variables in order to identify stable ratios. These ratios ...

  14. Banking Around the World

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Chinese banks expands its "going out" strategy but faces challenges in establishing a presence in foreign markets The world’s biggest lender by market value, the Industrial and Commercial Bank of China (ICBC), and the Hong Kong-based Bank of East Asia signed an agreement in which ICBC would pay $140.23 million to buy an 80-percent inter- est in Bank of East Asia USA, the Hong Kong bank said on January 23.

  15. Central bank Financial Independence

    OpenAIRE

    J.Ramon Martinez-Resano

    2004-01-01

    Central bank independence is a multifaceted institutional design. The financial component has been seldom analysed. This paper intends to set a comprehensive conceptual background for central bank financial independence. Quite often central banks are modelled as robot like maximizers of some goal. This perspective neglects the fact that central bank functions are inevitably deployed on its balance sheet and have effects on its income statement. A financially independent central bank exhibits ...

  16. Banking service in Germany

    Institute of Scientific and Technical Information of China (English)

    余璐

    2014-01-01

    <正>Germany is the prototypical economy country.Banks in Germany’s economic life plays a very important role.Germany has a large number of Banks and very dense network of bank branches.Deutsche Bank is by far the biggest German bank and Commerzbank is the second biggest.But with all the economic turmoil in the world these days,such rankings can change within

  17. Outsourcing central banking

    DEFF Research Database (Denmark)

    Khoury, Sarkis Joseph; Wihlborg, Clas

    2005-01-01

    The literature on Currency Boards (CB) stops at the water edge in terms of dealing with the totality of the functions of a central bank. Monetary policy, and banking supervisioncan be "outsourced" in an open economy with substantial foreign direct investment (FDI)in the banking sector if political...... the feasibility of, and constraints on, outsourcing of central bank functions. A brief discussion of the Argentinian experience is used for contrast.Key words: Currency Board, Foreign Banks, Supervision, Regional Integration,outsourcing....

  18. Outsourcing central banking

    DEFF Research Database (Denmark)

    Khoury, Sarkis Joseph; Wihlborg, Clas

    2005-01-01

    The literature on Currency Boards (CB) stops at the water edge in terms of dealing with the totality of the functions of a central bank. Monetary policy, and banking supervisioncan be "outsourced" in an open economy with substantial foreign direct investment (FDI)in the banking sector if political...... the feasibility of, and constraints on, outsourcing of central bank functions. A brief discussion of the Argentinian experience is used for contrast.Key words: Currency Board, Foreign Banks, Supervision, Regional Integration,outsourcing....

  19. How TK-TD and population models for aquatic macrophytes could support the risk assessment for plant protection products

    NARCIS (Netherlands)

    Hommen, U.; Schmitt, W.; Heine, S.; Brock, T.C.M.; Duquesne, S.; Manson, P.; Meregali, G.; Ochoa-Acuna, H.; Vliet, van P.; Arts, G.H.P.

    2016-01-01

    This case study of the SETAC workshop MODELINK demonstrates the potential use of mechanistic effects models for macrophytes to extrapolate from effects of a plant protection product observed in laboratory tests to effects resulting from dynamic exposure on macrophyte populations in edge-of-field wat

  20. Bimodality in stable isotope composition facilitates the tracing of carbon transfer from macrophytes to higher trophic levels

    NARCIS (Netherlands)

    Mendonca, R.; Kosten, S.; Lacerot, G.; Mazzeo, N.; Roland, F.; Ometto, J.P.; Paz, A.; Bueno, O.C.; Gomes, A.C.M.M.; Scheffer, M.

    2013-01-01

    Even though the suitability of macrophytes to act as a carbon source to food webs has been questioned by some studies, some others indicate that macrophyte-derived carbon may play an important role in the trophic transfer of organic matter in the food web of shallow lakes. To evaluate the importance

  1. Seed population dynamics on abandoned slopes in the hill and gully Loess Plateau region of China

    Science.gov (United States)

    Yu, Weijie; Jiao, Juying

    2017-04-01

    Recovery of natural vegetation is an effective but slow approach to control the soil erosion in the Chinese hill and gully Loess Plateau region. As seed stage is particularly vulnerable to environmental conditions, characteristics of seed population should be needed to study for determining whether the recovery of natural vegetation is limited during this stage on the abandoned slopes in this region. The study was performed on three abandoned slopes in a watershed with an area of 8.27 km2in the Shaanxi province of China. The differences in soil seed banks were investigated in two different points in time, late March2011 and early April 2013. Main factors of seed population dynamics, such as seed yield of dominant species, seed inputs by seed rain as well as seed outputs through seed loss by overland flow and seedling emergence, were monitored from late March 2011 to early April 2013. In this study, seed rain densities of the main later successional species, i.e., Lespedeza davurica, Stipa bungeana and Artemisia gmelinii accounted for 51.5-71.6% of their own seed yields. The soil seed bank density in early April 2013 was larger than that in late March 2011. The density of seed inputs by seed rain was 10186 seeds•m-2, and the total seed bank, including seed rain and seeds present in the soil seed bank in late March 2011, reached a density of 15018 seeds•m-2 during the study period. Seed densities of loss due to overland flow and seedling emergence were 79 seeds•m-2 from 20 species and 938 seedlings•m-2 that belonged to 38 species during a study period, and the seed output through them accounted for 0.5% and 6.3% of the total seed bank, respectively. The study concluded that overland flow could not result in large numbers of seeds loss and seeds were accumulating in the soil seed bank due to seed rain, and vegetation succession might be limited by curbed spatial seed dispersal and seedling establishment.

  2. 长期定位施肥对稻麦轮作农田土壤杂草种子库的影响%Changes in Weed Seed Bank Community of Agricultural Soils in Rice-Wheat Rotation Field Due to Long-Term Fertilization

    Institute of Scientific and Technical Information of China (English)

    蒋敏; 沈明星; 施林林; 沈新平; 戴其根

    2013-01-01

    [Objective] Characterizing the long-term effect of fertilization on weed seed bank community will aid in developing sustainable weed management practices and promoting crop yield.[Method] Weed seed bank was measured within a long-term fertilization from 1980 in the Taihu Lake region.Inorganic fertilizer treatments were selected as follows:CK (no fertilizer),N (N fertilizer),NP (N plus P fertilizer),NK (N plus P fertilizer),PK (P plus K fertilizer) and NPK (N plus P and K fertilizers).Weed seed density and community surveys were conducted and bio-diversity indices including Simpson index,Shannon index,Richness index,Evenness index were also calculated,at the same time,redundancy analysis (RDA) and correlation analysis were executed to mining the relationship between fertilizer management and weed seed bank.[Result] Seed densities of Monochoriav aginalis,Lindernia procumbens,Ammannia baccifera,Polygonum lapathifolium,Eleocharis yokoscensis,and Cyperus were high and dominant in different treatments,these weeds did a lot of damage to the growth of crops.Most of the weed seed densities decreased when nitrogen fertilizer was applied,the density ofE.yokoscensis decreased when phosphorus fertilizer was applied while the density of M.aginalis increased.The number of species and richness index of NPK treatment were the highest (P< 0.05),but its evenness index,Shannon index and Simpson index were significantly lower than those of the other treatments.[Conclusion] Long-term fertilization had changed the weed seed bank community in local area.The seed density decreased significantly when nitrogen fertilizer was applied.Phosphorus and potassium fertilizer had effects on the number of different weed species in the field.%[目的]解析长期不同施肥措施下稻麦两熟制农田土壤杂草种子库的异构性及其养分影响因素,为稻麦高产与杂草控制协同的养分管理提供依据.[方法]以太湖地区31年的长期肥料定位试验土壤为材料,采

  3. Ammonia-oxidizing Bacteria and Archaea in the Rhizosphere of Freshwater Macrophytes

    DEFF Research Database (Denmark)

    Herrmann, Martina; Schramm, Andreas

    2007-01-01

    measurements revealed clear differences in ammonia oxidation rates. The diversity of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) was assessed using the ammonia monooxygenase (amoA) gene as functional marker. Both AOA and AOB could be detected in the rhizosphere of all three plant......AMMONIA-OXIDIZING ARCHAEA AND BACTERIA IN THE RHIZOSPHERE OF FRESHWATER MACROPHYTES Martina Herrmann and Andreas Schramm Department of Biological Sciences, Microbiology, University of Aarhus, Denmark Aquatic macrophytes such as Littorella uniflora and Lobelia dortmanna release oxygen from......-specific microbial community distinct from that of unvegetated sediment and (ii) that aquatic macrophytes have an impact on abundance and activity of nitrifying and denitrifying bacteria in freshwater sediment. The goal of this study was to test these hypotheses for the key functional group for coupled nitrification...

  4. "Shadow Banking: Policy Challenges for Central Banks"

    OpenAIRE

    Moe, Thorvald Grung

    2014-01-01

    Central banks responded with exceptional liquidity support during the financial crisis to prevent a systemic meltdown. They broadened their tool kit and extended liquidity support to nonbanks and key financial markets. Many want central banks to embrace this expanded role as "market maker of last resort" going forward. This would provide a liquidity backstop for systemically important markets and the shadow banking system that is deeply integrated with these markets. But how much liquidity su...

  5. Pengelolaan Likuiditas Bank Syariah

    Directory of Open Access Journals (Sweden)

    Nurul Ichsan

    2014-01-01

    Full Text Available Islamic Banking Liquidity Management. This article is about management of liquidity which discuss about the position of cash money in the company and its ability to fulfill the obligation (pay the debt on time. Management of liquidity is one of the essential function which is done by banking institution and inside its efficient management, is needed instrument and finance market which is taking not only short term but also long term, and not only conventional banking but also syariat. Through that natural necessity (placement and fulfillment of short term need, for Islamic banking in Indonesia has been availabled some instruments such as (IMA certificate of Mudhorobah Investment between bank, (PUAS market banking regulations between syariat bank, (SWBI Bank of Indonesia Wadiah certificate, (FPJPS provision about short term cost facility for Islamic banks  DOI:10.15408/aiq.v6i1.1371

  6. Effects of high nitrogen concentrations on the growth of submersed macrophytes at moderate phosphorus concentrations.

    Science.gov (United States)

    Yu, Qing; Wang, Hong-Zhu; Li, Yan; Shao, Jian-Chun; Liang, Xiao-Min; Jeppesen, Erik; Wang, Hai-Jun

    2015-10-15

    Eutrophication of lakes leading to loss of submersed macrophytes and higher turbidity is a worldwide phenomenon, attributed to excessive loading of phosphorus (P). However, recently, the role of nitrogen (N) for macrophyte recession has received increasing attention. Due to the close relationship between N and P loading, disentanglement of the specific effects of these two nutrients is often difficult, and some controversy still exists as to the effects of N. We studied the effects of N on submersed macrophytes represented by Vallisneria natans (Lour.) Hara in pots positioned at three depths (0.4 m, 0.8 m, and 1.2 m to form a gradient of underwater light conditions) in 10 large ponds having moderate concentrations of P (TP 0.03 ± 0.04 mg L(-1)) and five targeted concentrations of total nitrogen (TN) (0.5, 2, 10, 20, and 100 mg L(-1)), there were two ponds for each treatment. To study the potential shading effects of other primary producers, we also measured the biomass of phytoplankton (ChlaPhyt) and periphyton (ChlaPeri) expressed as chlorophyll a. We found that leaf length, leaf mass, and root length of macrophytes declined with increasing concentrations of TN and ammonium, while shoot number and root mass did not. All the measured growth indices of macrophytes declined significantly with ChlaPhyt, while none were significantly related to ChlaPeri. Neither ChlaPhyt nor ChlaPeri were, however, significantly negatively related to the various N concentrations. Our results indicate that shading by phytoplankton unrelated to the variation in N loading and perhaps toxic stress exerted by high nitrogen were responsible for the decline in macrophyte growth.

  7. Factors involved in spatiotemporal dynamics of submerged macrophytes in a Portuguese coastal lagoon under Mediterranean climate

    Science.gov (United States)

    Antunes, Cristina; Correia, Otília; Marques da Silva, Jorge; Cruces, Anabela; Freitas, Maria da Conceição; Branquinho, Cristina

    2012-09-01

    Submerged macrophytes are key in coastal ecosystems, with important structural and functional roles. Thus, the characterization of the submerged aquatic vegetation dynamics is of prime importance for assessing the ecological status of coastal ecosystems. The main aim of this study was to assess the spatial and temporal dynamics of submerged macrophytes biomass in a temporarily open coastal lagoon in Melides, Portugal, and to evaluate the physiological performance of the dominant macrophyte in the system. This lagoon is subject to several disturbances such as the dramatic changes in water physicochemical parameters over time, since temporarily opens to the sea occur renewing the lagoon water content. Moreover it is under a Mediterranean climate with the inherently high temporal variability of precipitation and high temperatures during the summer. Our study shows that the submerged macrophyte community was dominated initially by Ruppia cirrhosa and then replaced by Potamogeton pectinatus, which showed a marked temporal and spatial pattern with extremely high values of biomass in August and in the inner part of the lagoon. The spatial and temporal biomass patterns in submerged macrophytes were mainly related with water level, salinity, pH and transparency. The physiological performance of R. cirrhosa was lower when there was greater biomass accumulation and in extremely shallow waters, whereas physiological vigor seemed to be greater at moderate temperatures and in areas with higher salinity and dissolved oxygen. The data from this study can be used to predict submerged biomass macrophyte responses to extreme water quality changes and to feed a decision support system for the best period to promote the seasonal artificial breaching of the sandy barrier.

  8. 黄土丘陵沟壑区植被自然恢复过程中土壤种子库特征%Studies on characteristics of soil seed banks in natural vegetation restoration of the Loess hilly gully regions

    Institute of Scientific and Technical Information of China (English)

    袁宝妮; 李登武; 李景侠; 王冬梅; 薛玲; 刘杰

    2009-01-01

    采用野外调查取样和室内实验相结合的方法,研究了黄土丘陵沟壑区植被自然恢复过程中土壤种子库的物种组成、密度、物种多样性以及相似性特征.结果表明:阴、阳坡10个样地中,共萌发了55种2203株幼苗,隶属于23科48属;总密度达到5 505±625.537粒/m~2,且0~5 cm土层远远大于5~10 cm土层的土壤种子库密度,约是其4.6倍;丰富度、多样性、均匀度指数均未与恢复年限达到显著相关水平,但生态优势度随恢复年限的增加呈上升趋势,且阳坡上升的趋势比阴坡明显;组成成分相似性系数变化范围为0.0952~0.7143,恢复年限相距越大,其相似性越小,说明植被恢复演替的过程也是土壤种子库空间异质性加大的过程.%Field survey and laboratory experiment were conducted to study the characteristics of soil seed bank, such as species composition, density, diversity and similarity in the natural vegetation restoration of loess hilly gully re-gions . The results showed that 2203 seedlings of 55 species, which belonged to 23 families and 48 genera, germinated in the 10 plots. The total seed density reached 5 505 ± 625.537 grains/m~2, approximately 4.6 times bigger in 0 ~ 5 cm than in 5 ~ 10 cm soil layer. The richness, diversity and evenness of soil seed bank did not achieve the remarkable relat-ed level with the restored age, but the ecological dominance increased while recovered years increased, and it took a more significant increasing trend in sunny slope than in shady slope. The similarity coefficients of soil seed bank composition ranged from 0.0952 to 0.7143, and the similarity coefficients got smaller with the increase of recovered years, which showed hat the vegetation succession of the abandoned cropland was basically an enlarging process of spatial heterogeneity.

  9. Macrophytes of the Grlište reservoir (Serbia: Fifteen years after its establishment

    Directory of Open Access Journals (Sweden)

    Stanković Ž.

    2009-01-01

    Full Text Available A large number of macrophytes, often in dense populations, have developed on the Grlište Reservoir, Serbia over a period of 15 years. Fast development of vegetation is a consequence of anthropogenic impact in lake management. The methodology used in this research covered 100% of the water body, including all areas with or without aquatic plants. The results indicate that plant communities are still in the early phase of development. This leaves space for future development of competitor macrophyte species (Najas marina, Eleocharis palustris, Typha latifolia, Typha angustifolia, Phragmites australis, etc. capable of endangering stability of the lake, which will tend toward eutrophication.

  10. Ammonia-oxidizing Bacteria and Archaea in the Rhizosphere of Freshwater Macrophytes

    DEFF Research Database (Denmark)

    Herrmann, Martina; Schramm, Andreas

    2007-01-01

    AMMONIA-OXIDIZING ARCHAEA AND BACTERIA IN THE RHIZOSPHERE OF FRESHWATER MACROPHYTES Martina Herrmann and Andreas Schramm Department of Biological Sciences, Microbiology, University of Aarhus, Denmark Aquatic macrophytes such as Littorella uniflora and Lobelia dortmanna release oxygen from...... measurements revealed clear differences in ammonia oxidation rates. The diversity of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) was assessed using the ammonia monooxygenase (amoA) gene as functional marker. Both AOA and AOB could be detected in the rhizosphere of all three plant...

  11. Aquatic macrophyte richness in Danish lakes in relation to alkalinity, transparency, and lake area

    DEFF Research Database (Denmark)

    Vestergaard, Ole Skafte; Sand-Jensen, Kaj

    2000-01-01

    alkalinity but 12.3 in lakes of high alkalinity due to a greater occurrence of the species-rich group of elodeids. Mean species richness per lake also increased significantly with increasing Secchi depth. No significant relationship between species richness and lake surface area was observed among the entire...... group of lakes or a subset of eutrophic lakes, as the growth of submerged macrophytes in large lakes may be restricted by wave action in shallow water and light restriction in deep water. In contrast, macrophyte species richness increased with lake surface area in transparent lakes, presumably due...

  12. Predicting aquatic macrophyte occurrence in soft-water oligotrophic lakes (Pyrenees mountain range

    Directory of Open Access Journals (Sweden)

    Cristina Pulido

    2014-08-01

    Full Text Available Distribution of aquatic macrophytes in lakes is related to geographical, morphological, catchment and water chemistry variables as well as human impacts, which modify the original environment. Here, we aim at building statistical models to establish the ecological niches of 11 aquatic macrophytes (10 different phanerogams and the genus Nitella from oligotrophic soft-water lakes and infer their ecological requirements and environmental constraints at the southernmost limit of their distribution. Macrophyte occurrence and environmental variables were obtained from 86 non-exploited oligotrophic soft-water lakes from the Pyrenees (Southern Europe; 42º50´N, 1º00´E; macrophytes inhabited 55 of these lakes. Optimum ranges and macrophyte occurrence were predicted in relation to 18 geographical, morphological, catchment and water chemistry variables using univariate and multivariate logistic models. Lakes at low altitude, in vegetated catchments and with low water concentration of NO3- and SO4-2, were the most suitable to host macrophytes. In general, individual species of aquatic macrophytes showed clear patterns of segregation along conductivity and pH gradients, although the specific combination of variables selected in the best models explaining their occurrence differed among species.  Based on the species response to pH and conductivity, we found Isoetes lacustris have its optimum in waters with low conductivity and pH (i.e. negative monotonic response. In contrast, Callitriche palustris, Ranunculus aquatilis, Subularia aquatica, Nitella spp., and Myriophyllum alterniflorum showed an optimum at intermediate values (i.e. unimodal response, whereas Potamogeton berchtoldii, Potamogeton alpinus, and Ranunculus trichophyllus as species had their optimum at relatively high water pH and conductivity (i.e. positive monotonic response. This pattern has been observed in other regions for the same species, although with different optima and tolerance

  13. Macrophytes may not contribute significantly to removal of nutrients, pharmaceuticals, and antibiotic resistance in model surface constructed wetlands.

    Science.gov (United States)

    Cardinal, Pascal; Anderson, Julie C; Carlson, Jules C; Low, Jennifer E; Challis, Jonathan K; Beattie, Sarah A; Bartel, Caitlin N; Elliott, Ashley D; Montero, Oscar F; Lokesh, Sheetal; Favreau, Alex; Kozlova, Tatiana A; Knapp, Charles W; Hanson, Mark L; Wong, Charles S

    2014-06-01

    Outdoor shallow wetland mesocosms, designed to simulate surface constructed wetlands to improve lagoon wastewater treatment, were used to assess the role of macrophytes in the dissipation of wastewater nutrients, selected pharmaceuticals, and antibiotic resistance genes (ARGs). Specifically, mesocosms were established with or without populations of Typha spp. (cattails), Myriophyllum sibiricum (northern water milfoil), and Utricularia vulgaris (bladderwort). Following macrophyte establishment, mesocosms were seeded with ARG-bearing organisms from a local wastewater lagoon, and treated with a single pulse of artificial municipal wastewater with or without carbamazepine, clofibric acid, fluoxetine, and naproxen (each at 7.6μg/L), as well as sulfamethoxazole and sulfapyridine (each at 150μg/L). Rates of pharmaceutical dissipation over 28d ranged from 0.073 to 3.0d(-1), corresponding to half-lives of 0.23 to 9.4d. Based on calculated rate constants, observed dissipation rates were consistent with photodegradation driving clofibric acid, naproxen, sulfamethoxazole, and sulfapyridine removal, and with sorption also contributing to carbamazepine and fluoxetine loss. Of the seven gene determinants assayed, only two genes for both beta-lactam resistance (blaCTX and blaTEM) and sulfonamide resistance (sulI and sulII) were found in sufficient quantity for monitoring. Genes disappeared relatively rapidly from the water column, with half-lives ranging from 2.1 to 99d. In contrast, detected gene levels did not change in the sediment, with the exception of sulI, which increased after 28d in pharmaceutical-treated systems. These shallow wetland mesocosms were able to dissipate wastewater contaminants rapidly. However, no significant enhancement in removal of nutrients or pharmaceuticals was observed in mesocosms with extensive aquatic plant communities. This was likely due to three factors: first, use of naïve systems with an unchallenged capacity for nutrient assimilation and

  14. Phenol toxicity to the aquatic macrophyte Lemna paucicostata

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji-Sook [Division of Life Science, University of Incheon, Incheon 406-840 (Korea, Republic of); Brown, Murray T. [School of Marine Science and Engineering, University of Plymouth, Plymouth, Devon PL4 8AA (United Kingdom); Han, Taejun, E-mail: hanalgae@hanmail.net [Division of Life Science, University of Incheon, Incheon 406-840 (Korea, Republic of); Institute of Green Environmental Research, University of Incheon, Incheon 406-840 (Korea, Republic of)

    2012-01-15

    Phenol is a ubiquitous environmental pollutant and a widely used reference toxicant for many bioassays. However, little information is available regarding the toxic effects of phenol on aquatic macrophytes. Seventy-two hour bioassays, with different end-points, were carried out to assess phenol toxicity in Lemna paucicostata. A concentration-dependent decline in frond multiplication and colony disintegration was observed, with 11.38 and 22.76 {mu}M phenol resulting in browning of fronds and colony disintegration, respectively. Growth of fronds, as measured by changes in surface area, was significantly inhibited with EC{sub 50} value of 2.70 {mu}M. When pulse amplitude modulated chlorophyll a (Chl a) fluorescence imaging (i-PAM) was employed, the maximum quantum yield of PS II (F{sub v}/F{sub m}) significantly declined with increasing phenol concentrations with resultant EC{sub 50} of 1.91 {mu}M and coefficients of variation (CVs) generated for the EC{sub 50} values of less than 4.7%. A gradual increase in fluorescence emissions from chlorophylls a and b and pheophytin up to a concentration of 2.85 {mu}M was found but declined markedly at higher concentrations. The significant correlation between the F{sub v}/F{sub m} and surface growth rate data implies that the former is an appropriate biomarker of whole plant toxicity. Using imaging Chl a fluorescence on L. paucicostata provides a rapid, sensitive and reliable method for assessing the toxic risks posed by phenol to aquatic ecosystems and has practical applications for municipal and industrial waste water management.

  15. Bank Syariah Sebagai Alternatif

    Directory of Open Access Journals (Sweden)

    Adang Sudjana

    2003-03-01

    Full Text Available The principle of not allowing interest practices (riba has saved the Syariah Bank and their customers from the effects of monetary crisis. In view of Islamic Principles, interest is forbidden. Therefore, all transactions of syariah banking are based on sale-purchase pattern. Besides, all good banking aspects as applied in conventional banking such as, 5 Cs (capital, collateral, capacity, character, and condition are also applied properly in the line of ukhrawi aspects in managing fund of syariah banking.  The practice of “mark-up” in project funded by syariah bank seems to be very difficult.

  16. Seed regulations and local seed systems

    NARCIS (Netherlands)

    Louwaars, N.

    2000-01-01

    Seed regulations have been introduced in most countries based on the development of formal seed production. Concerns about seed quality and about the varietal identity of the seeds have commonly led to seed laws. However, formal regulations are often inappropriate for informal seed systems, which

  17. Banking Postal Savings Bank in Sight

    Institute of Scientific and Technical Information of China (English)

    WANG PEI

    2006-01-01

    @@ Nine years of controversy regarding a national postal savings bank is expected to finally conclude this year. In April, the China Banking Regulatory Commission (CBRC)announced the establishment of a new department, one of the main functions of which will be to supervise postal savings.

  18. Kewenangan Bank Indonesia Dalam Likuiditas Bank Umum

    OpenAIRE

    Silvana R

    2008-01-01

    Perbankan merupakan pokok dari sistem keuangan setiap negara, karena perbankan merupakan salah satu motor penggerak pembangunan seluruh bangsa. Krisis perbankan berdampak pada turunnya kepercayaan masyarakat terhadap industri perbankan. Berbagai masalah di sektor perbankan yang tidak terdeteksi secara dini akan mengakibatkan runtuhnya kepercayaan masyarakat terhadap industri perbankan, Skripsi mi mengemukakan bagaimana penilaian kesehatan bank umum yang dilakukan oleh Bank Indonesia, bagai...

  19. Seed ecology of Lindera melissifolia (Lauraceae) as it relates to rarity of the species

    Science.gov (United States)

    Tracy Hawkins; Jeffery L. Walck; Siti N. Hidayati

    2011-01-01

    The seed ecology of the federally endangered shrub, Lindera melissifolia was investigated to determine if this aspect of the species life history contributes to the rarity of the species. Lindera melissifolia has the capacity to form a short-lived (two growing seasons) persistent soil seed bank if fruit pulp remains on seeds following dispersal and subsequent winter...

  20. Systemic banking crises

    OpenAIRE

    O. Emre Ergungor; James B. Thomson

    2005-01-01

    Systemic banking crises can have devastating effects on the economies of developing or industrialized countries. This Policy Discussion Paper reviews the factors that weaken banking systems and make them more susceptible to crises.

  1. FOREIGN BANKS WELCOMED

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Honoring its WTO commitments, China has begun to allow local incorporation by foreign banks, endowing them with the same status as their Chinese counterparts in an attempt to encourage diversified development in the Chinese banking sector On March 18, Wi

  2. GenBank

    Data.gov (United States)

    U.S. Department of Health & Human Services — GenBank is the NIH genetic sequence database, an annotated collection of all publicly available DNA sequences. GenBank is designed to provide and encourage access...

  3. Bank Resolution in the European Banking Union

    DEFF Research Database (Denmark)

    Gordon, Jeffrey N.; Ringe, Georg

    2015-01-01

    mechanism deployable at the discretion of the resolution authority must be available to supply liquidity to a reorganizing bank. On these conditions, a viable and realistic Banking Union would be within reach--and the resolution of global financial institutions would be greatly facilitated, not least......The project of creating a Banking Union is designed to overcome the fatal link between sovereigns and their banks in the Eurozone. As part of this project, political agreement for a common supervision framework and a common resolution scheme has been reached with difficulty. However, the resolution...... framework is weak, underfunded and exhibits some serious flaws. Further, Member States' disagreements appear to rule out a federalized deposit insurance scheme, commonly regarded as the necessary third pillar of a successful Banking Union. This paper argues for an organizational and capital structure...

  4. Bank Resolution in the European Banking Union

    DEFF Research Database (Denmark)

    Gordon, Jeffrey N.; Ringe, Wolf-Georg

    at the discretion of the resolution authority must be available to supply liquidity to a reorganizing bank. On these conditions, a viable and realistic Banking Union would be within reach — and the resolution of global financial institutions would be greatly facilitated, not least in a transatlantic perspective.......The project of creating a Banking Union is designed to overcome the fatal link between sovereigns and their banks in the Eurozone. As part of this project, political agreement for a common supervision framework and a common resolution scheme has been reached with difficulty. However, the resolution...... framework is weak, underfunded and exhibits some serious flaws. Further, Member States’ disagreements appear to rule out a federalized deposit insurance scheme, commonly regarded as the necessary third pillar of a successful Banking Union. This paper argues for an organizational and capital structure...

  5. The soil seed bank characteristics in cropland under different conservation tillage and fertilization regimes in Loess Hill and Gully Region%陕北黄土丘陵沟壑区水土保持耕作及施肥下农田土壤种子库特征

    Institute of Scientific and Technical Information of China (English)

    黄茂林; 梁银丽; 周茂娟; 韦泽秀; 吴燕

    2009-01-01

    To better understand the mechanism of weed occurrence and suppression effect of crops on weeds, we conducted a 4-year field experiment in 4 crops under different tillage and fertilization regimes in Ansai, Shaanxi, China. The species composition, seed density, diversity and the similarity were measured in soil seed bank of soybean (Glycine max), corn (Zea mays), Red Bean (Semen Phaseoli ) and potato (Solanum tuberosum). The tillage and fertilization treatments in each crop included till-chemical fertilizer (CF), till-organic manure (CM), till no fertilizer (CN), no-till chemical fertilizer (NF), no-till-organic manure (NM), and no-till-no fertilizer (NN). The results showed that: (1) There were 12 weed species in 1965 seedlings from 24 soil samples in 4 crops. These species belonged to 7 families and 12 genuses and 94% of them were annual weeds. Bangtou grass (fugax nees ex steud), amaranth (Acalypha australis), large crabgrass (Digitaria sanguinalis) and Poa(Poa sphondylodes)were the dominant species and accounted for 87%;(2) In 0-20cm soil of different treatments, weed density ranged from (282.9 ± 63) to (7482.5 ±1078.3) seeds · m-2. There were significant differences (P potato plot > soybean plot > corn plot among 4 crops, tillage plot > no-tillage plot between 2 tillage treatments, and organic fertilizer plot > Fertilizer plot > no fertilizer plot among fertilization treatments;(3) Soil seed bank had the highest weed density in NM Red Bean and the lowest density in NN corn. The rich index was the highest (2.30) in CF soybean and the lowest (0.29) in NN Red Bean. The diversity index was the highest in NN soybean (5.56) and the lowest in CF Red bean (0.45). The ecological advantage of NF corn was the highest (1.35) and that of CF soybean was the lowest (0.17). Among the fertilization treatments, the similar coefficient of soil seed bank ranged from 0 to 0.63 in tilled system and from 0.67 to 0.92 in no-till system. As a result, corn and soybean were optimal

  6. Audit of a bank

    OpenAIRE

    Ambros, Lukáš

    2012-01-01

    The goal of my thesis "Audit of a bank" is to identify and describe the area of external and internal audit in banking and to focus on specifics of bank audit in comparison to external audit of commercial enterprise. The first part is focused on audit of financial statements. In the second part are described the specifics of banking segment. Third part describes internal audit and cooperation between external and internal audit. In the last part there are described methods applied during the ...

  7. Time banking som ledelsesteknologi

    OpenAIRE

    Steensberg, Maja; Nielsen, Nadia Holm; Thomsen, Søren Tolshave

    2014-01-01

    This project examines how the English time banks Timber Wharf, Echo and Fair Shares affect their members and local environments. Based on Nikolas Rose’s theory on governmentality it is discussed, whether the time banks, understood as political actors, are challenging or reproducing neo-liberal governance. It is concluded that the way the time banks facilitates the concept of timebanking differs greatly. These different conducts are shaping the way in which the time banks are used by their mem...

  8. Audit of a bank

    OpenAIRE

    Ambros, Lukáš

    2012-01-01

    The goal of my thesis "Audit of a bank" is to identify and describe the area of external and internal audit in banking and to focus on specifics of bank audit in comparison to external audit of commercial enterprise. The first part is focused on audit of financial statements. In the second part are described the specifics of banking segment. Third part describes internal audit and cooperation between external and internal audit. In the last part there are described methods applied during the ...

  9. Essays on banking

    OpenAIRE

    Mosk, T.C.

    2014-01-01

    This dissertation studies how banks collect and process information. The first chapter studies how the organizational structure of banks affects the processing of information. The second chapter studies how banks use private information collected over the lending relationship in credit negotiations. The last chapter is joint work with Hans Degryse, Jose Liberti and Steven Ongena and studies how banks use ‘soft information’ to monitor small firms. This dissertation uses hand collected internal...

  10. Seed planting

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes prairie seed plantings on Neal Smith National Wildlife Refuge (formerly Walnut Creek National Wildlife Refuge) between 1992 and 2009.

  11. Easier Bank Access

    Institute of Scientific and Technical Information of China (English)

    Wang Jun

    2015-01-01

    Loosened banking regulations may spur an increase of foreign banks in China Foreign banks will soon have a much easier time setting up outlets in China.According to regulations recently amended by the State Council,as of January 1,foreign

  12. A BANK MANAGER SPEAKS

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    My name is Jane Carson and I'm the manager of savings bank in Portland,Oregon,My bank is open every day from8:30 in the moming until 4:00 in the aftermoon.On Fridays the bank remains oper until 6:30 in the evening.

  13. Banks on Notice

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Regulators issue policies to guide China’s banks as massive loans compromise the banking sector’s ability to contain future risks R egulatory departments are strengthening their supervision over financial institutions to prevent an incomprehensible financial scenario from unfolding: the failure of the Chinese banking

  14. Banking on Change

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The opening up of China’s banking sector took another giant step forward on March 20 when the first four foreign banks gained approval to incorporate locally. After going through commercial registration formalities, the banks will be able to con- duc

  15. Banking and Trading

    NARCIS (Netherlands)

    Boot, A.W.A.; Ratnovski, L.

    2016-01-01

    We study the interaction between relationship banking and short-term arm’s length activities of banks, called trading. We show that a bank can use the franchise value of its relationships to expand the scale of trading, but may allocate too much capital to trading ex post , compromising its ability

  16. Essays on banking

    NARCIS (Netherlands)

    Mosk, T.C.

    2014-01-01

    This dissertation studies how banks collect and process information. The first chapter studies how the organizational structure of banks affects the processing of information. The second chapter studies how banks use private information collected over the lending relationship in credit negotiations.

  17. Banking and Trading

    NARCIS (Netherlands)

    Boot, A.W.A.; Ratnovski, L.

    2016-01-01

    We study the interaction between relationship banking and short-term arm’s length activities of banks, called trading. We show that a bank can use the franchise value of its relationships to expand the scale of trading, but may allocate too much capital to trading ex post , compromising its ability

  18. Climate-related differences in the dominance of submerged macrophytes in shallow lakes

    NARCIS (Netherlands)

    Kosten, S.; Kamarainen, A.; Jeppesen, E.; Nes, van E.H.; Peeters, E.T.H.M.; Lacerot, G.; Scheffer, M.

    2009-01-01

    It has been suggested that shallow lakes in warm climates have a higher probability of being turbid, rather than macrophyte dominated, compared with lakes in cooler climates, but little field evidence exists to evaluate this hypothesis. We analyzed data from 782 lake years in different climate zones

  19. Bioprospecting of Marine Macrophytes Using MS-Based Lipidomics as a New Approach

    Directory of Open Access Journals (Sweden)

    Elisabete Maciel

    2016-03-01

    Full Text Available The marine environment supports a remarkable diversity of organisms which are a potential source of natural products with biological activities. These organisms include a wide variety of marine plants (from micro- to macrophytes, which have been used in the food and pharmaceutical industry. However, the biochemistry and biological activities of many of these macrophytes (namely macroalgae and halophytes, including seagrasses are still far from being fully explored. Most popular bioactive components include polysaccharides, peptides, phenolics and fatty acids (FAs. Polar lipids (glycolipids, phospholipids and betaine lipids are emerging as novel value-added bioactive phytochemicals, rich in n-3 FA, with high nutritional value and health beneficial effects for the prevention of chronic diseases. Polar lipids account various combinations of polar groups, fatty acyl chains and backbone structures. The polar lipidome of macrophytes is remarkably diverse, and its screening represents a significant analytical challenge. Modern research platforms, particularly mass spectrometry (MS-based lipidomic approaches, have been recently used to address this challenge and are here reviewed. The application of lipidomics to address lipid composition of marine macrophytes will contribute to the stimulation of further research on this group and foster the exploration of novel applications.

  20. Impact of submerged macrophytes including charophytes on phyto- and zooplankton communities: allelopathy versus other mechanisms

    NARCIS (Netherlands)

    Van Donk, E.; Van de Bund, W.J.

    2002-01-01

    Submerged macrophytes are crucial for the stabilization of the clear water state in shallow, mesotrophic and eutrophic lakes. Especially, charophytes often play an important role because they are typically rapid colonizers and because charophyte meadows are believed to have a particularly strong pos

  1. Archaea Dominate the Ammonia-Oxidizing Community in the Rhizosphere of the Freshwater Macrophyte Littorella uniflora

    DEFF Research Database (Denmark)

    Herrmann, Martina; Saunders, Aaron M.; Schramm, Andreas

    2008-01-01

    Archaeal and bacterial ammonia monooxygenase genes (amoA) had similar low relative abundances in freshwater sediment. In the rhizosphere of the submersed macrophyte Littorella uniflora, archaeal amoA was 500- to >8,000-fold enriched compared to bacterial amoA, suggesting that the enhanced nitrifi...... nitrification activity observed in the rhizosphere was due to ammonia-oxidizing Archaea....

  2. Ambiguous climate impacts on the competition between submerged macrophytes and phytoplankton in shallow lakes

    NARCIS (Netherlands)

    Kosten, S.; Jeppesen, E.; Huszar, V.M.; Mazzeo, N.; Nes, van E.H.; Peeters, E.T.H.M.; Scheffer, M.

    2011-01-01

    1. Shallow lakes may switch from a state dominated by submerged macrophytes to a phytoplankton-dominated state when a critical nutrient concentration is exceeded. We explore how climate change may affect this critical nutrient concentration by linking a graphical model to data from 83 lakes along a

  3. Effect of Hydrologic Alteration on the Community Succession of Macrophytes at Xiangyang Site, Hanjiang River, China

    Directory of Open Access Journals (Sweden)

    Na Yang

    2017-01-01

    Full Text Available With the intensification of human activities over the past three decades in China, adverse effects on river ecosystem become more serious especially in the Hanjiang River. Xiangyang site is an important spawn ground for four domestic fishes in the downstream region of Hanjiang River. Based on the field survey results of macrophytes during 1997–2000 and 2013-2014, community succession of aquatic macrophytes at Xiangyang site was evaluated and discussed. Two-key ecologic-related hydrologic characteristics, flow regime and water level, were identified as the main influence factors. The EFC (environmental flow components parameters were adopted to evaluate the alteration of flow regimes at Xiangyang site during 1941–2013. Evaluation results demonstrate a highly altered flow process after being regulated by reservoir. The flow patterns tend to be an attenuation process with no large floods occurring but a higher monthly low flow. Furthermore, the water level decreased and fluctuation reduced after the dam was built, which caused the decrease of biomass but favored the submerged macrophytes during 1995–2009. However, with the water level increasing after 2010 and gently fluctuating, due to uplift by the hydraulic projects downstream as well as the flow attenuation, the dominant position of submerged macrophytes will be weakened.

  4. Ecotypic differentiation in thermal traits in the tropical to warm-temperate green macrophyte Valonia utricularis

    NARCIS (Netherlands)

    Eggert, A.; Burger, E.M.; Breeman, Arno

    2003-01-01

    Differentiation of thermal traits (i.e. growth, survival and reproduction) was studied in the green macrophyte Valonia utricularis (Roth) C. Agardh, which has a world-wide tropical to warm-temperate distribution. Ecotypic differentiation between northeast Atlantic/Mediterranean and Indo-west Pacific

  5. Bioprospecting of Marine Macrophytes Using MS-Based Lipidomics as a New Approach.

    Science.gov (United States)

    Maciel, Elisabete; Costa Leal, Miguel; Lillebø, Ana Isabel; Domingues, Pedro; Domingues, Maria Rosário; Calado, Ricardo

    2016-03-08

    The marine environment supports a remarkable diversity of organisms which are a potential source of natural products with biological activities. These organisms include a wide variety of marine plants (from micro- to macrophytes), which have been used in the food and pharmaceutical industry. However, the biochemistry and biological activities of many of these macrophytes (namely macroalgae and halophytes, including seagrasses) are still far from being fully explored. Most popular bioactive components include polysaccharides, peptides, phenolics and fatty acids (FAs). Polar lipids (glycolipids, phospholipids and betaine lipids) are emerging as novel value-added bioactive phytochemicals, rich in n-3 FA, with high nutritional value and health beneficial effects for the prevention of chronic diseases. Polar lipids account various combinations of polar groups, fatty acyl chains and backbone structures. The polar lipidome of macrophytes is remarkably diverse, and its screening represents a significant analytical challenge. Modern research platforms, particularly mass spectrometry (MS)-based lipidomic approaches, have been recently used to address this challenge and are here reviewed. The application of lipidomics to address lipid composition of marine macrophytes will contribute to the stimulation of further research on this group and foster the exploration of novel applications.

  6. Mowing Submerged Macrophytes in Shallow Lakes with Alternative Stable States: Battling the Good Guys?

    NARCIS (Netherlands)

    Kuiper, Jan J.; Verhofstad, Michiel J. J. M.; Louwers, Evelien; Bakker, Elisabeth S.; Brederveld, Robert J.; van Gerven, Luuk P. A.; Janssen, Annette B. G.; de Klein, Jeroen J. M.; Mooij, Wolf M.

    2017-01-01

    Submerged macrophytes play an important role in maintaining good water quality in shallow lakes. Yet extensive stands easily interfere with various services provided by these lakes, and harvesting is increasingly applied as a management measure. Because shallow lakes may possess alternative stable

  7. Hydroponic Uptake of Atrazine and Lambda-cyhalothrin in Aquatic Macrophytes

    Science.gov (United States)

    Bouldin, J. L.; Farris, J. L.; Moore, M. T.; Smith, S.; Cooper, C. M.

    2005-05-01

    Phytoremediation encompasses an array of plant-associated processes known to mitigate contaminants from soil, sediment, and water. Modification of pesticides associated with agricultural runoff includes processes directly associated with aquatic macrophytes in addition to soil geochemical modifications and associated rhizospheric degradation. Remediation attributes of two vegetative species common to agricultural drainages in the Mississippi Delta, USA, were assessed using atrazine and lambda-cyhalothrin. Concentrations used in 8-d hydroponic exposures were calculated using recommended field applications and a 5% runoff model from a 0.65-cm rainfall event on a 2.02-ha field. While greater atrazine uptake was measured in Juncus effusus, greater lambda-cyhalothrin uptake occurred in Ludwigia peploides. Maximum pesticide uptake was reached within 48 h for each exposure and subsequent translocation of pesticides to upper plant biomass occurred in macrophytes exposed to atrazine. Sequestration of 98.2% of lambda-cyhalothrin in roots of L. peploides was measured after 8 d. Translocation of lambda-cyhalothrin in J. effusus resulted in 25.4% of pesticide uptake partitioned to upper plant biomass. These individual macrophyte remediation studies measured species- and pesticide-specific uptake rates, indicating that the seasonality of pesticide applications and macrophyte emergence might interact strongly to enhance mitigation capabilities in edge-of-field conveyance structures.

  8. Effects of contrasting omnivorous fish on submerged macrophyte biomass in temperate lakes: a mesocosm experiment

    NARCIS (Netherlands)

    Dorenbosch, M.; Bakker, E.S.

    2012-01-01

    1.Freshwater fish can affect aquatic vegetation directly by consuming macrophytes or indirectly by changing water quality. However, most fish in the temperate climate zone have an omnivorous diet. The impact of fish as aquatic herbivores in temperate climates therefore remains unclear and depends on

  9. Clonal variation in the thermal response of the submerged aquatic macrophyte Potamogeton pectinatus

    NARCIS (Netherlands)

    Pilon, J.; Santamaria, L.

    2002-01-01

    Broadly distributed plants have to cope with dramatic differences across latitude in the prevailing environmental temperature. We investigated the effect of water temperature on plant morphology, biomass accumulation and oxygen-exchange for five clones of the submerged aquatic macrophyte Potamogeton

  10. Effects of contrasting omnivorous fish on submerged macrophyte biomass in temperate lakes: a mesocosm experiment

    NARCIS (Netherlands)

    Dorenbosch, M.; Bakker, E.S.

    2012-01-01

    1.Freshwater fish can affect aquatic vegetation directly by consuming macrophytes or indirectly by changing water quality. However, most fish in the temperate climate zone have an omnivorous diet. The impact of fish as aquatic herbivores in temperate climates therefore remains unclear and depends on

  11. Interactions between piscivores, zooplanktivores and zooplankton in submerged macrophytes : Preliminary observations from enclosure and pond experiments

    DEFF Research Database (Denmark)

    Jacobsen, Lene; Perrow, M.R.; Landkildehus, F.

    1997-01-01

    behavioural changes of zooplanktivores has received little attention, even though this may be an important mechanism in enhancing the stability of submerged macrophytes in shallow lakes. Preliminary observations from an unreplicated large-scale field enclosure experiment and a replicated pond experiment...

  12. Effect of Hydrologic Alteration on the Community Succession of Macrophytes at Xiangyang Site, Hanjiang River, China

    Science.gov (United States)

    Duan, Kai

    2017-01-01

    With the intensification of human activities over the past three decades in China, adverse effects on river ecosystem become more serious especially in the Hanjiang River. Xiangyang site is an important spawn ground for four domestic fishes in the downstream region of Hanjiang River. Based on the field survey results of macrophytes during 1997–2000 and 2013-2014, community succession of aquatic macrophytes at Xiangyang site was evaluated and discussed. Two-key ecologic-related hydrologic characteristics, flow regime and water level, were identified as the main influence factors. The EFC (environmental flow components) parameters were adopted to evaluate the alteration of flow regimes at Xiangyang site during 1941–2013. Evaluation results demonstrate a highly altered flow process after being regulated by reservoir. The flow patterns tend to be an attenuation process with no large floods occurring but a higher monthly low flow. Furthermore, the water level decreased and fluctuation reduced after the dam was built, which caused the decrease of biomass but favored the submerged macrophytes during 1995–2009. However, with the water level increasing after 2010 and gently fluctuating, due to uplift by the hydraulic projects downstream as well as the flow attenuation, the dominant position of submerged macrophytes will be weakened. PMID:28127493

  13. Response of littoral macrophytes to water level fluctuations in a storage reservoir

    Directory of Open Access Journals (Sweden)

    Krolová M.

    2013-05-01

    Full Text Available Lakes and reservoirs that are used for water supply and/or flow regulations have usually poorly developed littoral macrophyte communities, which impairs ecological potential in terms of the EU Water Framework Directive. The aim of our study was to reveal controlling factors for the growth of littoral macrophytes in a storage reservoir with fluctuating water level (Lipno Reservoir, Czech Republic. Macrophytes occurred in this reservoir only in the eulittoral zone i.e., the shoreline region between the highest and the lowest seasonal water levels. Three eulittoral sub-zones could be distinguished: the upper eulittoral with a stable community of perennial species with high cover, the middle eulittoral with relatively high richness of emergent and amphibious species present at low cover values, and the lower eulittoral devoid of permanent vegetation. Cover and species composition in particular sub-zones were primarily influenced by the duration and timing of flooding, followed by nutrient limitation and strongly reducing conditions in the flooded organic sediment. Our results stress the ecological importance of eulittoral zone in reservoirs with fluctuating water levels where macrophyte growth can be supported by targeted management of water level, thus helping reservoir managers in improving the ecological potential of this type of water bodies.

  14. A microcosm system to evaluate the toxicity of the triazine herbicide simazine on aquatic macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    Vervliet-Scheebaum, Marco, E-mail: marco.vervliet@biologie.uni-freiburg.d [Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg (Germany); Straus, Alain [Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg (Germany); Tremp, Horst [Institute for Environmental Sciences, University Koblenz-Landau, Fortstr. 7, 76829 Landau (Germany); Hamer, Mick [Ecological Sciences, Syngenta Crop Protection AG, Jealott' s Hill International Research Centre, Bracknell, Berkshire RG42 6EY (United Kingdom); Maund, Stephen J. [Ecological Sciences, Syngenta Crop Protection AG, 4002 Basel (Switzerland); Wagner, Edgar [Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg (Germany); Schulz, Ralf [Institute for Environmental Sciences, University Koblenz-Landau, Fortstr. 7, 76829 Landau (Germany)

    2010-02-15

    This study evaluates the effects of the triazine herbicide simazine in an outdoor pond microcosm test system that contained two submerged rooted species (Myriophyllum spicatum and Elodea canadensis) and two emergent rooted species (Persicaria amphibia and Glyceria maxima) over a period of 84 days. Simazine was applied to the microcosms at nominal concentrations of 0.05, 0.5 and 5 mg/L. General biological endpoints and physiological endpoints were used to evaluate herbicide toxicity on macrophytes and the algae developing naturally in the system. Concentration-related responses of macrophytes and algae were obtained for the endpoints selected, resulting in a no observed ecologically adverse effect concentration (NOEAEC) at simazine concentrations of 0.05 mg active ingredient/L after 84 days. E. canadensis was the most negatively affected species based on length increase, which was consistently a very sensitive parameter for all macrophytes. The experimental design presented might constitute a suitable alternative to conventional laboratory single-species testing. - Simazine at concentrations of 0.05 mg/L does not cause long-term negative effects to aquatic macrophytes or algae.

  15. Aquatic macrophyte and macroinvertebrate diversity and conservation in wetlands of the Sinos River basin.

    Science.gov (United States)

    Maltchik, L; Rolon, A S; Stenert, C

    2010-12-01

    Wetlands are important sites for biological conservation because they support rich biodiversity and present high productivity. Species-area relationship is an important tool in conservation planning and it has been extensively used for wetland management. This study had as aims: (1) to analyse macrophyte and macroinvertebrate diversity in the fragmented wetlands of the Sinos River basin; and (2) to investigate whether wetland areas could work as a tool for selecting the important habitats for biodiversity conservation. Throughout the study, 56 species of macrophytes and 57 taxa of macroinvertebrates were identified. Macrophyte richness was related to the wetland area, but macroinvertebrate richness, however, was not related to the wetland area. The macrophyte and macroinvertebrate composition were not related to the wetland area. Species composition varied between the regions of the basin and the difference in the species composition occurred mainly by the distribution of macroinvertebrates. With regard to the biodiversity conservation of the Sinos River basin, the wetland area must not be a priority criterion for choosing the important wetlands for conservation. The environmental policies for biodiversity conservation must include management actions focused also on the protection of small wetlands. Moreover, other criteria should be analysed in further research such as habitat diversity, hydroperiod, geographic distribution and connectivity.

  16. Aquatic Plant Control Research Program. Effects of Organic Amendments to Sediment on Freshwater Macrophyte Growth.

    Science.gov (United States)

    1983-10-01

    The growth of three submersed macrophyte species (Myriophyllum spicatum, Hyjdri11a verticillata, and Elodea canadensis) and three partially emergent... Elodea canadensis Rich. in Michx; and Hydrilla verticillata (L.f.) Caspary. Nomenclature follows Godfrey and Wooten (1979, 1981). The first two species

  17. Effect of lighting conditions of coastal zone of Knyaginya lake on composition of macrophyte biohydrocenoses

    Directory of Open Access Journals (Sweden)

    B. O. Baranovsky

    2005-10-01

    Full Text Available In articlе the stuffs of researches of influence of a mode of illuminating intensity of coastal zone of a different exposition flood-land of lake Knyaginya (valley Samara on composition of highest aqueous green and macrozoobentos macrophytes biogeocenose are submitted.

  18. Interaction between the macrophyte Stratiotes aloides and filamentous algae: does it indicate allelopathy?

    NARCIS (Netherlands)

    Mulderij, G.; Mau, B.; De Senerpont Domis, L.N.; Smolders, A.J.P.; Van Donk, E.

    2009-01-01

    The aquatic macrophyte Stratiotes aloides Linnaeus, which has recently received attention in studies on allelopathy, has been shown to suppress phytoplankton growth. In the Netherlands, S. aloides often co-occurs with floating filamentous algae. However, filamentous algae are generally absent in

  19. Impact of submerged macrophytes including charophytes on phyto- and zooplankton communities: allelopathy versus other mechanisms

    NARCIS (Netherlands)

    Van Donk, E.; Van de Bund, W.J.

    2002-01-01

    Submerged macrophytes are crucial for the stabilization of the clear water state in shallow, mesotrophic and eutrophic lakes. Especially, charophytes often play an important role because they are typically rapid colonizers and because charophyte meadows are believed to have a particularly strong

  20. A simple equation for describing the temperature dependent growth of free-floating macrophytes

    NARCIS (Netherlands)

    Heide, van Tj.; Roijackers, R.M.M.; Nes, van E.H.; Peeters, E.T.H.M.

    2006-01-01

    Temperature is one of the most important factors determining growth rates of free-floating macrophytes in the field. To analyse and predict temperature dependent growth rates of these pleustophytes, modelling may play an important role. Several equations have been published for describing temperatur

  1. Removal of personal care compounds from sewage sludge in reed bed container (lysimeter) studies - Effects of macrophytes

    DEFF Research Database (Denmark)

    Chen, Xijuan; Pauly, Udo; Rehfus, Stefan

    2009-01-01

    as on the bactericide Triclosan. Additionally, the capacity of different macrophytes species to affect the treatment process was examined. Three different macrophyte species were compared: bulrush (Typha latifolia), reed (Phragmites australis) and reed canary grass (Phalaris arundinacea). They were planted...... into containers (lysimeters) with a size of 1 m × 1 m × 1 m which were filled with 20 cm gravel at the bottom and 50 cm sludge on top, into which the macrophytes were planted. During the twelve months experiment reduction of 20-30% for HHCB and AHTN, 70% for Triclosan and 70% for OTNE were determined under...

  2. Use of low-altitude aerial photography to identify submersed aquatic macrophytes

    Science.gov (United States)

    Schloesser, Donald W.; Manny, Bruce A.; Brown, Charles L.; Jaworski, Eugene

    1987-01-01

    The feasibility of using low-altitude aerial photography to identify beds of submersed macrophytes is demonstrated. True color aerial photos and collateral ground survey information for submersed aquatic macrophyte beds at 10 sites in the St.Clair-Detroit River system were obtained in September 1978. Using the photos and collateral ground survey information, a dichotomous key was developed for the identification of six classes - beds of five genera of macrophytes and one substrate type. A test was prepared to determine how accurately photo interpreters could identify the six classes. The test required an interpreter to examine an unlabeled, outlined area on photographs and identify it using the key. Six interpreters were tested. One pair of interpreters was trained in the interpretation of a variety of aerial photos, a second pair had field experience in the collection and identification of submersed macrophytes in the river system, and a third pair had neither training in the interpretation of aerial photos nor field experience. The criteria that we developed were applied equally well by the interpretors, regardless of their training or experience. Overall accuracy (i.e., omission errors) of all six classes combined was 68% correct, whereas, overall accuracy of individual classes ranged from 50 to 100% correct. Mapping accuracy (i.e. omission and commission errors) of individual classes ranged from 36 to 75%. Although the key developed for this study has only limited application outside the context of the data and sites examined in this study, it is concluded that low-altitude aerial photography, together with limited amounts of collateral ground survey information, can be used to economically identify beds of submersed macrophytes in the St. Clair-Detroit River system and other similar water bodies.

  3. Aquatic macrophytes can be used for wastewater polishing but not for purification in constructed wetlands

    Science.gov (United States)

    Tang, Yingying; Harpenslager, Sarah F.; van Kempen, Monique M. L.; Verbaarschot, Evi J. H.; Loeffen, Laury M. J. M.; Roelofs, Jan G. M.; Smolders, Alfons J. P.; Lamers, Leon P. M.

    2017-02-01

    The sequestration of nutrients from surface waters by aquatic macrophytes and sediments provides an important service to both natural and constructed wetlands. While emergent species take up nutrients from the sediment, submerged and floating macrophytes filter nutrients directly from the surface water, which may be more efficient in constructed wetlands. It remains unclear, however, whether their efficiency is sufficient for wastewater purification and how plant species and nutrient loading affects nutrient distribution over plants, water and sediment. We therefore determined nutrient removal efficiencies of different vegetation (Azolla filiculoides, Ceratophyllum demersum and Myriophyllum spicatum) and sediment types (clay, peaty clay and peat) at three nutrient input rates, in a full factorial, outdoor mesocosm experiment. At low loading (0.43 mg P m-2 d-1), plant uptake was the main pathway (100 %) for phosphorus (P) removal, while sediments showed a net P release. A. filiculoides and M. spicatum showed the highest biomass production and could be harvested regularly for nutrient recycling, whereas C. demersum was outcompeted by spontaneously developing macrophytes and algae. Higher nutrient loading only stimulated A. filiculoides growth. At higher rates ( ≥ 21.4 mg P m-2 d-1), 50-90 % of added P ended up in sediments, with peat sediments becoming more easily saturated. For nitrogen (N), 45-90 % was either taken up by the sediment or lost to the atmosphere at loadings ≥ 62 mg N m-2 d-1. This shows that aquatic macrophytes can indeed function as an efficient nutrient filter but only for low loading rates (polishing) and not for high rates (purification). The outcome of this controlled study not only contributes to our understanding of nutrient dynamics in constructed wetlands but also shows the differential effects of wetland sediment types and plant species. Furthermore, the acquired knowledge may benefit the application of macrophyte harvesting to remove

  4. The role of submerged macrophytes and macroalgae in nutrient cycling: A budget approach

    Science.gov (United States)

    Human, Lucienne R. D.; Snow, Gavin C.; Adams, Janine B.; Bate, Guy C.; Yang, Sheng-Chi

    2015-03-01

    This study used a budget approach to determine the effect of submerged macrophytes and macroalgae on the storage of N and P in an estuary. Above and below ground tissue content of nitrogen and phosphorus were determined for the various macrophyte species. The mouth of the estuary was artificially breached in February 2011 with a volume of 0.3 × 106 m3 and closed a week later. A 1:100 year flood with volume close to 3 × 106 m3 breached the mouth naturally in June 2011 flushing water and sediment out of the estuary. In order to track the change in the nutrient acquisition of the submerged macrophytes and macroalgae over a closed-mouth state, the nutrient budget was constructed for the period February 2011 to July 2011, from the time the mouth closed until it opened again. Relative to other inputs the sediment contributed 30% of the TN and 40% TP toward the nutrient budget, while the submerged macrophytes and macroalgae stored 20-30 % TN and 30-38 % TP. The river and precipitation contributed less than 3% of the TN and TP input. It was previously thought that the sediments of South African temporarily open/closed estuaries did not have the necessary organic stock to fuel primary production. However this research showed this to be incorrect. Submerged macrophytes and macroalgae significantly influenced nutrient cycling and this is the first detailed account of incorporating vegetation into a nutrient budget without relying solely on C:N:P ratios.

  5. BANKING WITHOUT INTEREST

    Directory of Open Access Journals (Sweden)

    Jana Ilieva

    2017-06-01

    Full Text Available In recent years, there has been increased global awareness of Islamic finance. This topic is mainly opened with respect to the great financial crisis that mostly hit the banking system and the financial markets and caused many bank bankruptcies and state interventions. This paper analyzes the basic principles of Islamic banking. The absolute prohibition of receiving and giving interest (Riba and profit-and-loss sharing (PLS paradigms are elaborated in detail; they are primarily based on mudarabah (profit-sharing and musyarakah (joint venture concepts which nowadays are becoming an accepted way of doing business in several Western multinational banks. An overall comparison of the advantages of Islamic vs. conventional banking is also given. Islamic finance technology solutions have matured and they will face various challenges in the following decades, due to conventional banks offering, increasingly, Islamic products. The need for a more comprehensive environment and regulatory framework is emphasized, so that Islamic banking development can be ensured.

  6. Bank Resolution in the European Banking Union

    DEFF Research Database (Denmark)

    Gordon, Jeffrey N.; Ringe, Georg

    2015-01-01

    The project of creating a Banking Union is designed to overcome the fatal link between sovereigns and their banks in the Eurozone. As part of this project, political agreement for a common supervision framework and a common resolution scheme has been reached with difficulty. However, the resolution...... framework is weak, underfunded and exhibits some serious flaws. Further, Member States' disagreements appear to rule out a federalized deposit insurance scheme, commonly regarded as the necessary third pillar of a successful Banking Union. This paper argues for an organizational and capital structure....... The FDIC's experience teaches us three important lessons: First, systemically important financial institutions need to have in their liability structure sufficient unsecured (or otherwise subordinated) term debt so that in the event of bank failure, the conversion of debt into equity will be sufficient...

  7. Central bank capital, financial strength, and the Bank of Japan

    OpenAIRE

    Thomas F. Cargill

    2006-01-01

    This Economic Letter addresses central bank capital and financial strength in the context of Bank of Japan policy (Cargill 2005). Specifically, it reviews general considerations about central bank capital and financial strength, discusses recent Bank of Japan policy in the context of capital structure, evaluates the Bank of Japan's concern in the context of the broader issue of central bank independence, and draws some lessons from recent Bank of Japan policy.

  8. Recognising macrophyte-vegetated environments in the rock record: a new criterion using 'hooked' forms of crustose coralline red algae

    Science.gov (United States)

    Beavington-Penney, Simon J.; Paul Wright, V.; Woelkerling, Wm. J.

    2004-04-01

    The role of macrophytes (such as seagrasses) in influencing deposition in shallow marine environments has long been understood. They affect sediment textures such that they do not reflect ambient hydrodynamic conditions, and so the recognition of ancient vegetated environments is important for accurate palaeoenvironmental analysis. However, there is little direct fossil evidence of such plants in the rock record, and so the presence of former macrophyte cover generally has to be inferred from indirect evidence based on the characteristics of modern macrophyte-vegetated environments. We present a new criterion for the recognition of vegetated environments in the rock record, based upon a distinctive 'hooked' form of crustose coralline red algae that is definitively indicative of growth on seagrasses (and also on other macrophytes with similarly flattened blades), and has been recognised from both modern (Inhaca Island, Mozambique) and fossil (the Eocene of Oman) seagrass beds.

  9. Macrophyte succession in floodplain lakes : spatio-temporal patterns in relation to river hydrology, lake morphology and management

    NARCIS (Netherlands)

    Geest, van G.J.

    2005-01-01

    Two questions are central to the work in this thesis: 1. What are the factors determining macrophyte composition in floodplain lakes along the Lower Rhine? 2. What advice can be given for design of future water bodies?

  10. Seed storage at elevated partial pressure of oxygen, a fast method for analysing seed ageing under dry conditions

    Science.gov (United States)

    Groot, S. P. C.; Surki, A. A.; de Vos, R. C. H.; Kodde, J.

    2012-01-01

    Background and Aims Despite differences in physiology between dry and relative moist seeds, seed ageing tests most often use a temperature and seed moisture level that are higher than during dry storage used in commercial practice and gene banks. This study aimed to test whether seed ageing under dry conditions can be accelerated by storing under high-pressure oxygen. Methods Dry barley (Hordeum vulgare), cabbage (Brassica oleracea), lettuce (Lactuca sativa) and soybean (Glycine max) seeds were stored between 2 and 7 weeks in steel tanks under 18 MPa partial pressure of oxygen. Storage under high-pressure nitrogen gas or under ambient air pressure served as controls. The method was compared with storage at 45 °C after equilibration at 85 % relative humidity and long-term storage at the laboratory bench. Germination behaviour, seedling morphology and tocopherol levels were assessed. Key Results The ageing of the dry seeds was indeed accelerated by storing under high-pressure oxygen. The morphological ageing symptoms of the stored seeds resembled those observed after ageing under long-term dry storage conditions. Barley appeared more tolerant of this storage treatment compared with lettuce and soybean. Less-mature harvested cabbage seeds were more sensitive, as was the case for primed compared with non-primed lettuce seeds. Under high-pressure oxygen storage the tocopherol levels of dry seeds decreased, in a linear way with the decline in seed germination, but remained unchanged in seeds deteriorated during storage at 45 °C after equilibration at 85 % RH. Conclusions Seed storage under high-pressure oxygen offers a novel and relatively fast method to study the physiology and biochemistry of seed ageing at different seed moisture levels and temperatures, including those that are representative of the dry storage conditions as used in gene banks and commercial practice. PMID:22967856

  11. Banking System in Kyrgyz Republic

    OpenAIRE

    Sagbansu, Lutfu

    2006-01-01

    This paper examines the overall banking system and the basic banking system development factors such as internet banking and deposit insurance in the world and particularly in Kyrgyzstan. The analyses show that progress in banking reform, introduction of deposit insurance and internet banking concepts are essential for avoiding harmful problems, development stable and solvent banking system. These developments include the more effective regulation of the entry and exit of banks, removal of ob...

  12. Morphometry and retention time as forcing functions to establishment and maintenance of aquatic macrophytes in a tropical reservoir

    OpenAIRE

    M. B. Cunha-Santino; Fushita,A. T.; PERET, A.C.; Bianchini-Junior,I.

    2016-01-01

    Abstract Macrophytes may constitute an important resource for several chemical, physical and biological processes within aquatic ecosystems. This study considers that in tropical reservoirs with low retention time and with low values of shoreline development (DL), the expansion and persistence of aquatic macrophytes are mainly reported to local conditions (e.g., hydrodynamic and wind exposure) rather than trophic status and depth of the euphotic zone. In this context, this study aimed at desc...

  13. Decreasing but still significant facilitation effect of cold-season macrophytes on wetlands purification function during cold winter

    OpenAIRE

    Xiangxu Zou; Hui Zhang; Jie Zuo; Penghe Wang; Dehua Zhao; Shuqing An

    2016-01-01

    To identify the facilitation effect of a cool-season aquatic macrophyte (FEam) for use in effluent purification via constructed floating wetlands (CFWs) and to determine the possible pathways used during a winter period with an average temperature of less than 5??C, pilot-scale CFWs were planted with the cold-season macrophyte Oenanthe clecumbens and were operated as batch systems. Although some leaves withered, the roots retained relatively high levels of activity during the winter, which ha...

  14. Aquatic macrophytes in the large, sub-tropical Itaipu Reservoir, Brazil.

    Science.gov (United States)

    Mormul, Roger Paulo; Ferreira, Fernando Alves; Michelan, Thaisa Sala; Carvalho, Priscilla; Silveira, Marcio José; Thomaz, Sidinei Magela

    2010-12-01

    In the last three decades, rapid assessment surveys have become an important approach for measuring aquatic ecosystem biodiversity. These methods can be used to detect anthropogenic impacts and recognize local or global species extinctions. We present a floristic survey of the aquatic macrophytes along the Brazilian margin of the Itaipu Reservoir conducted in 2008 and compare this with a floristic survey conducted ten years earlier. We used ordination analysis to determine whether assemblage composition differed among reservoir arms. Macrophyte species were sampled in each of the 235 sampling stations using a boat, which was positioned inside three places of each macrophyte stand to record species and search for small plants. We also collected submerged plants using a rake with the boat moving at constant velocity for ten minutes. We assigned individual macrophyte species to life form and identified representative species for each life form. A total of 87 macrophyte taxa were identified. The "emergent" life forms contained the highest number of species, followed by "rooted submerged" life forms. The extensive survey of macrophytes undertaken in September 2008 recorded more species than a survey conducted between 1995 and 1998. This could be due to changes in water physico-chemistry, disturbances due to water drawdown and the long period between surveys, which may have allowed natural colonization by other species. Additionally, differences in the classification systems and taxonomic resolution used in the surveys may account for differences in the number of species recorded. Assemblage composition varied among the arms and was affected by underwater radiation (as measured using a Secchi disk) and fetch. Five non-native species were found. Two of these non-native species (Urochloa subquadripara and Hydrilla verticillata) are of special concern because they have a high frequency of occurrence and occupy large marginal areas of the reservoir. Future surveys should be

  15. Remote Sensing supports EULAKES project for mapping submerged macrophytes in Lake Garda

    Science.gov (United States)

    Matta, Erica; Bresciani, Mariano; Giardino, Claudia; Bolpagni, Rossano; Pellegrini, Giovanna; Braga, Federica

    2013-04-01

    Lake bottoms have an important role in the aquatic ecosystem: bathymetry and morphology may affect the hydrodynamic processes in coastal waters, while the presence of aquatic macrophytes helps to preserve the ecology. Within the context of macrophyte monitoring programs, technical advances in remote sensing with higher spatial and spectral resolutions provide opportunities for big scale ecological studies, with the possibility to assess a multitemporal analysis. One of the objectives of the EULAKES project has been to map aquatic vegetation cover inside the Garda Lake from hyperspectral MIVIS (Multispectral Infrared and Visible Imaging Spectrometer) aerial images thanks to the application of a bio-optical model inversion technique (BOMBER: Bio-Optical Model Based tool for Estimating water quality and bottom properties from Remote sensing images). MIVIS images, with a spectral resolution of 102 bands, working between 430 and 1270 nm, were previously corrected for atmospheric, adjacency and glint effects before being processed with the BOMBER tool. One complete MIVIS overflight (12 runs) acquired on June 27th 2011, allowed the retrieval of a macrophyte presence map all around the first 7m deep coastal belt, with a validation error of about 10%, resulting from 89 in situ measures performed during images acquisition. A relevant spatial distribution could be observed, with higher aquatic plants concentration in the Southern part of the lake. A further local cover distribution map localized on the Sirmione Peninsula was integrated with previous results to perform a temporal analysis of macrophyte colonization patterns along this reduced littoral zone for the last 14 years (acquisitions on September 1997, July 2005 and July 2010). Considerable modifications in terms of macrophyte structural complexity and colonized areas were detectable: a drastic reduction of well-established dense communities (more than 70% of cover) and increasing of un-colonized areas were followed by

  16. Banks, regions and development

    Directory of Open Access Journals (Sweden)

    Pietro Alessandrini

    2003-03-01

    Full Text Available From the 1980s onwards the banking sectors in all the industrialised countries have been experiencing intense restructuring, aggregation and consolidation, radically changing their ownership structures and geography. Whatever the reasons behind such restructuring processes, the globalisation of the credit markets, the consolidation of banking structures, the removal of barriers to the free location of banks and their penetration of peripheral markets pose two main questions. Will integration of the banking systems lead to a narrowing or a widening of the development gap between regions? What relations will there be between financial centres and the periphery, and how will financial labour be divided between national (international banks and local (regional banks? The aim of this paper is to address such questions in the light of recent developments in the theoretical and empirical literature on financial integration.

  17. Tissue banking in australia.

    Science.gov (United States)

    Ireland, Lynette; McKelvie, Helen

    2003-01-01

    The legal structure for the regulation of tissue banking has existed for many years. In Australia, the donation of human tissue is regulated by legislation in each of the eight States and Territories. These substantially uniform Acts were passed in the late 1970's and early 1980's, based on model legislation and underpinned by the concept of consensual giving. However, it was not until the early 1990's that tissue banking came under the notice of regulatory authorities. Since then the Australian Government has moved quickly to oversee the tissue banking sector in Australia. Banked human tissue has been deemed to be a therapeutic good under the Therapeutic Goods Act 1989, and tissue banks are required to be licensed by the Therapeutic Goods Administration and are audited for compliance with the Code of Good Manufacturing Practice- Human Blood and Tissues. In addition, tissue banks must comply with a myriad of other standards, guidelines and recommendations.

  18. COMMERCIAL BANK LIQUIDITY MANAGEMENT

    OpenAIRE

    KOREKOV A.V.

    2015-01-01

    Bank liquidity management and optimal resource allocation of commercial bank Nostro accounts balances receive much less attention from the scientists compared to the questions on capital structure, funding, credit risk analysis and stress testing. Optimal liquidity management is a way to lower bank costs and risks, which are going to increase over time, especially when money markets are dry of free funds. There are two sides of the issue to be analyzed. The optimal resource allocation and cor...

  19. Bank Record Processing

    Science.gov (United States)

    1982-01-01

    Barnett Banks of Florida, Inc. operates 150 banking offices in 80 Florida cities. Banking offices have computerized systems for processing deposits or withdrawals in checking/savings accounts, and for handling commercial and installment loan transactions. In developing a network engineering design for the terminals used in record processing, an affiliate, Barnett Computing Company, used COSMIC's STATCOM program. This program provided a reliable network design tool and avoided the cost of developing new software.

  20. Bank Resolution in Europe

    DEFF Research Database (Denmark)

    N. Gordon, Jeffery; Ringe, Georg

    2015-01-01

    Bank resolution is a key pillar of the European Banking Union. This column argues that the current structure of large EU banks is not conducive to an effective and unbiased resolution procedure. The authors would require systemically important banks to reorganise into a ‘holding company’ structure......, where the parent company holds unsecured term debt sufficient to cover losses at its operating financial subsidiaries. This would facilitate a ‘single point of entry’ resolution procedure, minimising the risk of creditor runs and destructive ring-fencing by national regulators....

  1. Essays on banking and regulation

    NARCIS (Netherlands)

    Todorov, R.I.

    2013-01-01

    This thesis consists of three chapters that explore issues related to bank capital, multinational bank supervision, and bank lending in a developing country. The first chapter explores the impact of peer banks on bank capital adjustments. The second chapter evaluates the extent to which distortions

  2. Factors Determining Mergers of Banks in Malaysia's Banking Sector Reform

    National Research Council Canada - National Science Library

    Rubi Ahmad; Mohamed Ariff; Michael Skully

    2007-01-01

    What was termed government-guided merger was a unique banking sector reform implemented in 2002 by the central bank of Malaysia guiding a larger number of depository institutions to form 10 large banks...

  3. Study of aquatic macrophytes in the wetlands on the territory of Vrachanski Balkan nature park

    Directory of Open Access Journals (Sweden)

    Valčev Vladimir V.

    2010-01-01

    Full Text Available An overall study of the species composition and abundance of macrophytes in all open water bodies of a large protected territory was made for the first time in Bulgaria. Four high-mountain eutrophic lakes and the upper stretches of three rivers within the boundaries of Vrachanski Balkan Nature Park were investigated. Thirty-nine macrophyte species (higher plants and mosses were identified scattered around, or forming more or less distinct vegetation groups. Three of the lakes are new for the country locations of the species Elatine alsinastrum and Peplis portula. The processes of eutrophication are more advanced in the lakes. The habitats formed around the investigated water bodies have been determined. They are three habitats of European Community interest for Bulgaria. The major threats for the investigated wetlands on the territory of the Park are pointed out.

  4. Cadmium and chromium removal kinetics from solution by two aquatic macrophytes.

    Science.gov (United States)

    Suñe, N; Sánchez, G; Caffaratti, S; Maine, M A

    2007-01-01

    The aim of this work was to determine chromium and cadmium bioaccumulation processes of two free-floating macrophytes commonly used in wetlands for water treatment: Salvinia herzogii and Pistia stratiotes. Metal removal from the solution involves two stages: a fast one and a slow one. The fast stage of the Cd uptake is significantly different for each species, while it is not significantly different in Cr uptake. The most important processes of Cd uptake are biological ones in S. herzogii and adsorption, chelation and ionic exchange are in P. stratiotes. The main processes of Cr uptake in both macrophytes are adsorption, chelation and ion exchange. The slow stage is different for each species and metal. Cr precipitation induced by roots occurs in P. stratiotes. Cr uptake through leaves is probably the main cause of the increase of Cr in the aerial parts of S. herzogii.

  5. Removal of nutrients and veterinary antibiotics from swine wastewater by a constructed macrophyte floating bed system.

    Science.gov (United States)

    Xian, Qiming; Hu, Lixia; Chen, Hancheng; Chang, Zhizhou; Zou, Huixian

    2010-12-01

    The potential of three varieties of Italian ryegrass (Lolium multiflorum Lam.), Dryan, Tachimasari and Waseyutaka, to improve the water quality of swine wastewater was evaluated using a constructed macrophyte floating bed system. With respect to reductions in levels of nutrients, chemical oxygen demand (COD), and sulfonamide antimicrobials (SAs, including sulfadiazine, sulfamethazine, and sulfamethoxazole), Dryan performed better than Tachimasari and Waseyutaka. For Dryan, total N was reduced by 84.0%, total P by 90.4%, COD by 83.4% and sulfonamide antimicrobials by 91.8-99.5%. Similar results were observed for Tachimasari and Waseyutaka. The results indicated that the treatment of swine wastewater using the constructed macrophyte floating bed system was effective in the removal of nutrients and veterinary antibiotics.

  6. Aquatic macrophytes from Danube Delta lagoons Musura Bay and Zatonul Mare

    Directory of Open Access Journals (Sweden)

    Sava D.,

    2016-05-01

    Full Text Available The Romanian Danube Delta, a unique, young and continuing to grow region situated in the eastern part of Europe, is the largest continuous marshland and the second largest delta on the continent, and also a favorable place for developing a unique flora and fauna in Europe, with many rare and protected species. The predominance of the aquatic environment, led to the existence of a particular macrophytic flora. In this context, the purpose of this paper is to contribute to the study of aquatic macrophytes. The present study took place over two years, between 2013-2014, and in each year a number of expeditions were made in the two lagoons (Musura Bay and Zătonul Mare in different seasons, in order to observe the diverse flora, because, due to seasonal variation in water quality, there might be a significantly seasonality of the vegetation also.

  7. Islamic banks and profitability: an empirical analysis of Indonesian banking

    OpenAIRE

    Jordan, Sarah

    2013-01-01

    This paper provides an empirical analysis of the factors that determine the profitability of Indonesian banks between the years 2006-2012. In particular, it investigates whether there are any significant differences in terms of profitability between Islamic banks and commercial banks. The results, obtained by applying the system-GMM estimator to the panel of 54 banks, indicate that the high bank profitability during these years were determined mainly by the size of the banks, the market share...

  8. Removing bank subsidies leads inexorably to full reserve banking

    OpenAIRE

    Musgrave, Ralph S.

    2013-01-01

    The recent banking crisis laid bare a long standing and inherent defect in fractional reserve banking: the fact that fractional reserve is unlikely to work for long without taxpayer backing. Changing bank regulations in such a way that banks are never a burden on taxpayers leads inexorably to full reserve banking. Full reserve involves splitting the banking industry into two halves. A safe half where depositors earn no interest, but they do have instant access to their money, and a second...

  9. Removing bank subsidies leads inexorably to full reserve banking

    OpenAIRE

    Musgrave, Ralph S.

    2013-01-01

    The recent banking crisis laid bare a long standing and inherent defect in fractional reserve banking: the fact that fractional reserve is unlikely to work for long without taxpayer backing. Changing bank regulations in such a way that banks are never a burden on taxpayers leads inexorably to full reserve banking. Full reserve involves splitting the banking industry into two halves. A safe half where depositors earn no interest, but they do have instant access to their money, and a second...

  10. Bank Lending and Relationship Banking: Evidence from Chilean Firms

    OpenAIRE

    Andrea Repetto; Sergio Rodríguez; Rodrigo O. Valdés

    2002-01-01

    In this paper we empirically study bank-client relationships using a sample of manufacturing Chilean firms. We examine whether concentration and the duration of bank-firm relationships affect the terms of bank financing, evaluating both the volume of bank lending and bank loan costs. Our results indicate that lower concentration, measured by the number of banks a firm borrows from, is associated with lower costs of loans and with a large and positive non-lincar effect on borrowing. The length...

  11. Dual Banking Systems and Interest Rate Risk for Islamic Banks

    OpenAIRE

    Bacha, Obiyathulla I.

    2004-01-01

    In introducing Islamic banking in Malaysia, the basic strategy was to replicate the products/ services offered by conventional banks. The successful implementation of such a strategy has meant that Malaysia today has a truly dual banking system. Islamic banks in Malaysia not only have product similarity with conventional banks but share the same overall economic environment and a common customer base. The ability of non Muslim customers/depositors to switch between the two banking syste...

  12. Potential carry-over of seeds from 11 common shrub and vine competitors of loblolly and shortleaf pines

    Science.gov (United States)

    Michael G. Shelton; Michael D. Cain

    2002-01-01

    Many of the competitors of the regeneration of loblolly and shortleaf pines (Pinus taeda, L. and Pinus echinata Mill., respectively) develop from seed disseminated on the site after reproduction cutting or from the seed bank. To evaluate the potential carry-over of the seeds from 11 shrub and vine competitors of these two...

  13. Methods of Payment to Banks: e-Banking. Comparative Study on Three Banks

    Directory of Open Access Journals (Sweden)

    Miranda Petronella VLAD

    2012-11-01

    Full Text Available E-banking website, majority offers the banks. At first it was electronic-banking, Internet-banking followed, followed by mobile-banking service. These services offer the same facilities, Customer Bank just that varies the channel used for communication with the Bank. The services offered by banks through E-banking, approves: compilation of orders; scheduled payments; orders for payment of wages; internal transfers; pay rates on internal or external; currency exchanges; view balances of accounts at any time; information about foreign exchange rates; view and print account statements; the definition of beneficiaries of direct payments by the client.

  14. Polyphenols with algicidal activity in the submerged macrophyte Myriophyllum Spicatum L.

    OpenAIRE

    Gross, Elisabeth; Sütfeld, Rainer

    1994-01-01

    The role of phenols as defence mechanisms in various terrestrial plants is well studied. However, in aquatic environments, they are probably involved also in the chemical interactions between species. A periodic shift from dominance by submerged macrophytes to dominance by phytoplankton and vice versa without apparent change in the external nutrient loading is sometimes observed in shallow eutrophic lakes. Due to the fact that nutrient levels are not usually limiting to phytoplankton growth, ...

  15. Comparability of river quality assessment using macrophytes: a multi-step procedure to overcome biogeographical differences.

    Science.gov (United States)

    Aguiar, F C; Segurado, P; Urbanič, G; Cambra, J; Chauvin, C; Ciadamidaro, S; Dörflinger, G; Ferreira, J; Germ, M; Manolaki, P; Minciardi, M R; Munné, A; Papastergiadou, E; Ferreira, M T

    2014-04-01

    This paper exposes a new methodological approach to solve the problem of intercalibrating river quality national methods when a common metric is lacking and most of the countries share the same Water Framework Directive (WFD) assessment method. We provide recommendations for similar works in future concerning the assessment of ecological accuracy and highlight the importance of a good common ground to make feasible the scientific work beyond the intercalibration. The approach herein presented was applied to highly seasonal rivers of the Mediterranean Geographical Intercalibration Group for the Biological Quality Element Macrophytes. The Mediterranean Group of river macrophytes involved seven countries and two assessment methods with similar acquisition data and assessment concept: the Macrophyte Biological Index for Rivers (IBMR) for Cyprus, France, Greece, Italy, Portugal and Spain, and the River Macrophyte Index (RMI) for Slovenia. Database included 318 sites of which 78 were considered as benchmarks. The boundary harmonization was performed for common WFD-assessment methods (all countries except Slovenia) using the median of the Good/Moderate and High/Good boundaries of all countries. Then, whenever possible, the Slovenian method, RMI was computed for the entire database. The IBMR was also computed for the Slovenian sites and was regressed against RMI in order to check the relatedness of methods (R(2)=0.45; p<0.00001) and to convert RMI boundaries into the IBMR scale. The boundary bias of RMI was computed using direct comparison of classification and the median boundary values following boundary harmonization. The average absolute class differences after harmonization is 26% and the percentage of classifications differing by half of a quality class is also small (16.4%). This multi-step approach to the intercalibration was endorsed by the WFD Regulatory Committee. © 2013 Elsevier B.V. All rights reserved.

  16. Aquiatic macrophytes in Doñana protected area (SW Spain).

    OpenAIRE

    García Murillo, Pablo; Fernández Zamudio, María del Rosario; Cirujano Bracamonte, Santos; Sousa Martín, Arturo

    2006-01-01

    A big portion of the Doñana protected areas corresponds to wetlands; in them aquatic macrophytes are the main primary producers and play also other important ecological functions. Nevertheless, they are inconspicuous organisms and their importance in these ecosystems does not seem to be well reflected in the bibliography about this natural area. This paper reviews the most significant information gathered about this group of organisms in this protected area, provides an updated catal...

  17. Native macrophyte density and richness affect the invasiveness of a tropical poaceae species.

    Directory of Open Access Journals (Sweden)

    Thaisa S Michelan

    Full Text Available The role of the native species richness and density in ecosystem invasibility is a matter of concern for both ecologists and managers. We tested the hypothesis that the invasiveness of Urochloa arrecta (non-native in the Neotropics is negatively affected by the species richness and abundance of native aquatic macrophytes in freshwater ecosystems. We first created four levels of macrophyte richness in a greenhouse (richness experiment, and we then manipulated the densities of the same native species in a second experiment (density experiment. When the native macrophytes were adults, fragments of U. arrecta were added, and their growth was assessed. Our results from the richness experiment corroborated the hypothesis of a negative relationship between the native species richness and the growth of U. arrecta, as measured by sprout length and root biomass. However, the resistance to invasion was not attributed to the presence of a particular native species with a greater competitive ability. In the density experiment, U. arrecta growth decreased significantly with an increased density of all five of the native species. Density strongly affected the performance of the Poaceae in a negative manner, suggesting that patches that are densely colonized by native macrophytes and less subject to disturbances will be more resistant to invasion than those that are poorly colonized and more commonly subjected to disturbances. Our density experiment also showed that some species exhibit a higher competitive ability than others (sampling effect. Although native richness and abundance clearly limit the colonization and establishment of U. arrecta, these factors cannot completely prevent the invasion of aquatic ecosystems by this Poaceae species.

  18. Native macrophyte density and richness affect the invasiveness of a tropical poaceae species.

    Science.gov (United States)

    Michelan, Thaisa S; Thomaz, Sidinei M; Bini, Luis M

    2013-01-01

    The role of the native species richness and density in ecosystem invasibility is a matter of concern for both ecologists and managers. We tested the hypothesis that the invasiveness of Urochloa arrecta (non-native in the Neotropics) is negatively affected by the species richness and abundance of native aquatic macrophytes in freshwater ecosystems. We first created four levels of macrophyte richness in a greenhouse (richness experiment), and we then manipulated the densities of the same native species in a second experiment (density experiment). When the native macrophytes were adults, fragments of U. arrecta were added, and their growth was assessed. Our results from the richness experiment corroborated the hypothesis of a negative relationship between the native species richness and the growth of U. arrecta, as measured by sprout length and root biomass. However, the resistance to invasion was not attributed to the presence of a particular native species with a greater competitive ability. In the density experiment, U. arrecta growth decreased significantly with an increased density of all five of the native species. Density strongly affected the performance of the Poaceae in a negative manner, suggesting that patches that are densely colonized by native macrophytes and less subject to disturbances will be more resistant to invasion than those that are poorly colonized and more commonly subjected to disturbances. Our density experiment also showed that some species exhibit a higher competitive ability than others (sampling effect). Although native richness and abundance clearly limit the colonization and establishment of U. arrecta, these factors cannot completely prevent the invasion of aquatic ecosystems by this Poaceae species.

  19. COMPARISON OF METHODS TO DETECT ALLELOPATHIC EFFECTS OF SUBMERGED MACROPHYTES ON GREEN ALGAE(1).

    Science.gov (United States)

    Hilt Nee Körner, Sabine; Beutler, Eike; Bauer, Nadine

    2012-02-01

    Detecting allelopathic inhibition of phytoplankton by submerged macrophytes in an ecologically meaningful way is not easy. Multiple-approach investigations from a laboratory scale to the ecosystem level have been recommended to overcome the shortcomings of individual methods. Whether results of different methods are qualitatively or quantitatively comparable has not yet been tested. Here, we compare the sensitivity of the green algae Desmodesmus subspicatus (Chodat) E. Hegewald et Ant. Schmidt and Stigeoclonium helveticum Vischer to the allelopathic effect of the submerged macrophyte Myriophyllum verticillatum L. The following three approaches were used: (i) coincubation of algae in dialysis membrane tubes in a lake inside and outside a M. verticillatum stand, (ii) coincubation of algae in dialysis membrane tubes in aquaria with and without M. verticillatum, and (iii) single additions of tannic acid (TA), an allelopathically active polyphenol present in this macrophyte, to the algae cultures. For each method, fluorescence-based (chl a, PSII activity) and particle-based (cell count, biovolume) parameters were compared after 48 h of incubation. Results revealed quantitative and qualitative differences between methods. Algae incubated in dialysis membrane tubes in aquaria showed a strong decrease in all parameters under the influence of macrophytes. In situ measurements were influenced by adverse growth conditions for the test algae and only detected significant reductions for biovolume. Single additions of TA induced a strong reduction of fluorescence-based parameters similar to aquarium results, but an increase in the cell count. Even the qualitative transfer of laboratory results to field conditions thus requires caution and a proper selection of parameters.

  20. Ocean Acidification Differentially Affects the Photosynthesis of Key New England Macrophytes

    Science.gov (United States)

    Fachon, E.; Ets-Hokin, J. M.; Donham, E. M.; Price, N.

    2016-02-01

    While the influence of anthropogenic CO2 emissions on seawater chemistry is detrimental to calcification among CaCO3 reliant organisms such as commercially important shellfish species, non-calcareous macrophytes like seagrasses and seaweeds can experience enhanced growth under elevated pCO2 conditions and may be a substantial, if ephemeral, CO2 sink. Most marine macrophytes rely on enzyme conversion of HCO3- to supply the inorganic carbon necessary for photosynthesis; the ability to down-regulate this energetically expensive carbon acquisition under high pCO2 conditions could determine future species success. We exposed four commercially and ecologically relevant New England macrophytes (Saccharina latissima, Fucus vesiculosus, Ulva lactuca, and Zostera marina) to pre-industrial (280 uatm), present (400 and 520 utam - recorded in Casco Bay) and future (640, 880 and 1120 uatm - as predicted by the IPCC) pCO2 levels in 1.5 hr long respirometry assays after 72 hrs acclimation. CO2 consumption, photosynthetic quotient (Q = CO2 consumed:O2 evolved), and change in carbonate saturation state (Ωcalcite) were calculated for each sample using differences in initial and final carbonate chemistry and dissolved oxygen concentrations. All species experienced increases in rate of CO2 uptake and Q under elevated pCO2 treatments, but response level differed across species. Saccharina latissima had the greatest relative effect on all parameters measured, consuming 4 times more carbon at high pCO2 levels than the lowest performing species. While all macrophytes were able to raise Ωcalcite, the magnitude of change decreased at higher pCO2 levels, suggesting a limitation to the degree to which photosynthesis can locally raise calcification potential for sensitive native or farmed populations of shellfish in the future. The varied responses observed across species have implications for future community structures and for phytoremediation efforts.

  1. Do Amplitudes of Water Level Fluctuations Affect the Growth and Community Structure of Submerged Macrophytes?

    Science.gov (United States)

    Wang, Mo-Zhu; Liu, Zheng-Yuan; Luo, Fang-Li; Lei, Guang-Chun; Li, Hong-Li

    2016-01-01

    Submerged macrophytes are subjected to potential mechanical stresses associated with fluctuating water levels in natural conditions. However, few experimental studies have been conducted to further understand the effects of water level fluctuating amplitude on submerged macrophyte species and their assemblages or communities. We designed a controlled experiment to investigate the responses of three submerged macrophyte species (Hydrilla verticillata, Ceratophyllum demersum and Elodea nuttallii) and their combinations in communities to three amplitudes (static, ± 30 cm, ± 60 cm) of water level fluctuations. Results showed that water level fluctuating amplitude had little effects on the community performance and the three tested species responded differently. H. verticillata exhibited more growth in static water and it was negatively affected by either of the water level fluctuations amplitude, however, growth parameters of H. verticillata in two fluctuating water level treatments (i.e., ± 30 cm, ± 60 cm) were not significantly different. On the other hand, the growth of C. demersum was not significantly correlated with different amplitude treatments. However, it became more abundant when water levels fluctuated. E. nuttallii was inhibited by the two fluctuating water level treatments, and was less in growth parameters compared to the other species especially in water level fluctuating conditions. The inherent differences in the adaptive capabilities of the tested species indicate that C. demersum or other species with similar responses may be dominant species to restore submerged macrophyte communities with great fluctuating water levels. Otherwise, H. verticillata, E. nuttallii or other species with similar responses could be considered for constructing the community in static water conditions.

  2. Toxicity of Zinc on Growth of an Aquatic Macrophyte, Ipomoea Aquatica Forsk

    OpenAIRE

    Laitonjam Bedabati Chanu; Abhik Gupta

    2016-01-01

    The effects of different concentrations of Zn on growth of an aquatic macrophyte, Ipomoea aquatica Forsk. were studied. Fresh weight, dry weight, shoot length, root length, number of nodes, development of leaves, and chlorophyll and carotene contents were the different growth parameters considered. Toxicity symptoms like browning and decaying of roots could be observed in plants treated at 22.7 mg L-1 Zn as early as 3rd day of experiment while yellowing of older leaves appeared during the lat...

  3. Macrophytes of the Grlište reservoir (Serbia): Fifteen years after its establishment

    OpenAIRE

    Stanković Ž.; Borišev M.; Simić Slobodanka; Vučković Milijana; Igić Ružica; Vidović Milka; Miljanović B.

    2009-01-01

    A large number of macrophytes, often in dense populations, have developed on the Grlište Reservoir, Serbia over a period of 15 years. Fast development of vegetation is a consequence of anthropogenic impact in lake management. The methodology used in this research covered 100% of the water body, including all areas with or without aquatic plants. The results indicate that plant communities are still in the early phase of development. This leaves space for future development of competitor macro...

  4. 78 FR 12360 - PNC Bank, National Association, Retail Bank Franklin, PA; PNC Bank, National Association, Retail...

    Science.gov (United States)

    2013-02-22

    ... Employment and Training Administration PNC Bank, National Association, Retail Bank Franklin, PA; PNC Bank, National Association, Retail Bank West Chester, IL; Notice of Negative Determination Regarding Application... Assistance (TAA) applicable to workers and former workers of PNC Bank, National Association, Retail...

  5. Bank profitability: Insights from the rural banking industry in Ghana

    Directory of Open Access Journals (Sweden)

    Michael Adusei

    2015-12-01

    Full Text Available This paper analyzes the profitability of 112 rural banks (special unit banks created to promote rural financial intermediation in Ghana. The results generally show that bank size, funding risk, diversification, liquidity risk, and bank stability are significant predictors of rural bank profitability. Whereas an improvement in the funding risk of a rural bank in a particular period portends a drop in its profitability in the future, an improvement in the size, diversification, liquidity risk, and stability of a rural bank signifies an improvement in the future profitability of the bank.

  6. The macroeconomics of banking

    NARCIS (Netherlands)

    van der Kwaak, C.G.F.

    2017-01-01

    This thesis studies the macroeconomic effectiveness of monetary and fiscal policy in an environment where commercial banks are undercapitalized after a financial crisis and have large holdings of (risky) government bonds on their balance sheets. An undercapitalized banking system cannot perfectly el

  7. Destroy The Bank! (case)

    NARCIS (Netherlands)

    Star, G.J. Van der; Maas, A.

    2016-01-01

    DZ Bank faces some significant challenges for the near future. One of them is the way payments are being made. This case is about Stefan, the Strategic Management Consultant of DZ Bank. He struggles with innovations and new technologies, such as Bitcoins. What does this mean for the future of the ba

  8. Optimal central bank transparency

    NARCIS (Netherlands)

    van der Cruijsen, C.A.B.; Eijffinger, S.C.W.; Hoogduin, L.

    2008-01-01

    Should central banks increase their degree of transparency any further? We show that there is likely to be an optimal intermediate degree of central bank transparency. Up to this optimum more transparency is desirable: it improves the quality of private sector inflation forecasts. But beyond the opt

  9. Optimal central bank transparency

    NARCIS (Netherlands)

    van der Cruijsen, C.A.B.; Eijffinger, S.C.W.; Hoogduin, L.H.

    2010-01-01

    Should central banks increase their degree of transparency any further? We show that there is likely to be an optimal intermediate degree of central bank transparency. Up to this optimum more transparency is desirable: it improves the quality of private sector inflation forecasts. But beyond the opt

  10. Innovative strategies of bank

    Directory of Open Access Journals (Sweden)

    G.A Peresadko

    2012-03-01

    Full Text Available The article deals with the specifics of banking innovations, the global trends of innovative strategies in the banking sector was described, analyzed the necessary methodology for their implementation, proposed plan of innovative activities and its possible application in Ukraine.

  11. Banking and trading

    NARCIS (Netherlands)

    Boot, A.W.A.; Ratnovski, L.

    2013-01-01

    We study the interaction between relationship banking and short-term, scalable arm’s length finance which we call trading. Relationship banking is not scalable, has high franchise value, is long-term oriented and low risk. Trading is transaction-based: scalable, with lower margins (capital constrain

  12. Banking and trading

    NARCIS (Netherlands)

    Boot, A.W.A.; Ratnovski, L.

    2013-01-01

    We study the interaction between relationship banking and short-term, scalable arm’s length finance which we call trading. Relationship banking is not scalable, has high franchise value, is long-term oriented and low risk. Trading is transaction-based: scalable, with lower margins (capital

  13. Essays in empirical banking

    NARCIS (Netherlands)

    Bai, Y.

    2015-01-01

    This dissertation consists of three essays on empirical banking. They study how do information and political activeness affect banks’ lending behavior, as well as the effect of lending relationship with banks on firms’ stock performance during interbank liquidity crunch. The first essay looks at a t

  14. Destroy The Bank! (case)

    NARCIS (Netherlands)

    dr. A. Maas; G.J. Van der Star

    2016-01-01

    DZ Bank faces some significant challenges for the near future. One of them is the way payments are being made. This case is about Stefan, the Strategic Management Consultant of DZ Bank. He struggles with innovations and new technologies, such as Bitcoins. What does this mean for the future of the

  15. Cellulase and xylanase activity during the decomposition of three aquatic macrophytes in a tropical oxbow lagoon

    Directory of Open Access Journals (Sweden)

    L Sciessere

    2011-09-01

    Full Text Available Due to the connection between enzymatic activity and degradation of different fractions of organic matter, enzyme assays can be used to estimate degradation rates of particulate and dissolved organic carbon in freshwater systems. The aim of this study was to quantify and model the enzymatic degradation involving the decomposition of macrophytes, describing temporal activity of cellulases (EC 3.2.1.4 and EC 3.2.1.91 and xylanase (EC 3.2.1.8 during in situ decomposition of three aquatic macrophytes (Salvinia sp., Eichhornia azurea and Cyperus giganteus on the surface and water-sediment interface (w-s interface of an oxbow lagoon (Óleo lagoon within a natural Brazilian Savanna Reserve. Overall, the enzymatic degradation of aquatic macrophytes in Óleo lagoon occurred during the whole year and was initiated together with leaching. Xylanase production was ca. 5 times higher than cellulase values due to easy access to this compound by cellulolytic microorganisms. Enzymatic production and detritus mass decay were similar on the surface and w-s interface. Salvinia sp. was the most recalcitrant detritus, with low mass decay and enzymatic activity. E. azurea and C. giganteus decomposition rates and enzymatic production were high and similar. Due to the physicochemical homogeneity observed in the Óleo lagoon, the differences between the decay rates of each species are mostly related with detritus chemical quality.

  16. Kinetics of Cr(III) and Cr(VI) removal from water by two floating macrophytes.

    Science.gov (United States)

    Maine, M A; Hadad, H R; Sánchez, G; Caffaratti, S; Pedro, M C

    2016-01-01

    The aim of this work was to compare Cr(III) and Cr(VI) removal kinetics from water by Pistia stratiotes and Salvinia herzogii. The accumulation in plant tissues and the effects of both Cr forms on plant growth were also evaluated. Plants were exposed to 2 and 6 mg L(-1) of Cr(III) or Cr(VI) during 30 days. At the end of the experiment, Cr(VI) removal percentages were significantly lower than those obtained for Cr(III) for both macrophytes. Cr(III) removal kinetics involved a fast and a slow component. The fast component was primarily responsible for Cr(III) removal while Cr(VI) removal kinetics involved only a slow process. Cr accumulated principally in the roots. In the Cr(VI) treatments a higher translocation from roots to aerial parts than in Cr(III) treatments was observed. Both macrophytes demonstrated a high ability to remove Cr(III) but not Cr(VI). Cr(III) inhibited the growth at the highest studied concentration of both macrophytes while Cr(VI) caused senescence. These results have important implications in the use of constructed wetlands for secondary industrial wastewater treatment. Common primary treatments of effluents containing Cr(VI) consists in its reduction to Cr(III). Cr(III) concentrations in these effluents are normally below the highest studied concentrations in this work.

  17. Assessment of the Potential Biological Activity of Low Molecular Weight Metabolites of Freshwater Macrophytes with QSAR

    Directory of Open Access Journals (Sweden)

    Evgeny A. Kurashov

    2016-01-01

    Full Text Available The paper focuses on the assessment of the spectrum of biological activities (antineoplastic, anti-inflammatory, antifungal, and antibacterial with PASS (Prediction of Activity Spectra for Substances for the major components of three macrophytes widespread in the Holarctic species of freshwater, emergent macrophyte with floating leaves, Nuphar lutea (L. Sm., and two species of submergent macrophyte groups, Ceratophyllum demersum L. and Potamogeton obtusifolius (Mert. et Koch, for the discovery of their ecological and pharmacological potential. The predicted probability of anti-inflammatory or antineoplastic activities above 0.8 was observed for twenty compounds. The same compounds were also characterized by high probability of antifungal and antibacterial activity. Six metabolites, namely, hexanal, pentadecanal, tetradecanoic acid, dibutyl phthalate, hexadecanoic acid, and manool, were a part of the major components of all three studied plants, indicating their high ecological significance and a certain universalism in their use by various species of water plants for the implementation of ecological and biochemical functions. This report underlines the role of identified compounds not only as important components in regulation of biochemical and metabolic pathways and processes in aquatic ecological systems, but also as potential pharmacological agents in the fight against different diseases.

  18. Assessment of the Potential Biological Activity of Low Molecular Weight Metabolites of Freshwater Macrophytes with QSAR.

    Science.gov (United States)

    Kurashov, Evgeny A; Fedorova, Elena V; Krylova, Julia V; Mitrukova, Galina G

    2016-01-01

    The paper focuses on the assessment of the spectrum of biological activities (antineoplastic, anti-inflammatory, antifungal, and antibacterial) with PASS (Prediction of Activity Spectra for Substances) for the major components of three macrophytes widespread in the Holarctic species of freshwater, emergent macrophyte with floating leaves, Nuphar lutea (L.) Sm., and two species of submergent macrophyte groups, Ceratophyllum demersum L. and Potamogeton obtusifolius (Mert. et Koch), for the discovery of their ecological and pharmacological potential. The predicted probability of anti-inflammatory or antineoplastic activities above 0.8 was observed for twenty compounds. The same compounds were also characterized by high probability of antifungal and antibacterial activity. Six metabolites, namely, hexanal, pentadecanal, tetradecanoic acid, dibutyl phthalate, hexadecanoic acid, and manool, were a part of the major components of all three studied plants, indicating their high ecological significance and a certain universalism in their use by various species of water plants for the implementation of ecological and biochemical functions. This report underlines the role of identified compounds not only as important components in regulation of biochemical and metabolic pathways and processes in aquatic ecological systems, but also as potential pharmacological agents in the fight against different diseases.

  19. Cadmium and chromium removal kinetics from solution by two aquatic macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    Sune, N. [Quimica Analitica-Facultad de Ingenieria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), U.N.L. Sgo del Estero 2829, 3000 Santa Fe (Argentina); Sanchez, G. [Quimica Analitica-Facultad de Ingenieria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), U.N.L. Sgo del Estero 2829, 3000 Santa Fe (Argentina); Caffaratti, S. [Quimica Analitica-Facultad de Ingenieria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), U.N.L. Sgo del Estero 2829, 3000 Santa Fe (Argentina); Maine, M.A. [Quimica Analitica-Facultad de Ingenieria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), U.N.L. Sgo del Estero 2829, 3000 Santa Fe (Argentina)]. E-mail: amaine@fiqus.unl.edu.ar

    2007-01-15

    The aim of this work was to determine chromium and cadmium bioaccumulation processes of two free-floating macrophytes commonly used in wetlands for water treatment: Salvinia herzogii and Pistia stratiotes. Metal removal from the solution involves two stages: a fast one and a slow one. The fast stage of the Cd uptake is significantly different for each species, while it is not significantly different in Cr uptake. The most important processes of Cd uptake are biological ones in S. herzogii and adsorption, chelation and ionic exchange are in P. stratiotes. The main processes of Cr uptake in both macrophytes are adsorption, chelation and ion exchange. The slow stage is different for each species and metal. Cr precipitation induced by roots occurs in P. stratiotes. Cr uptake through leaves is probably the main cause of the increase of Cr in the aerial parts of S. herzogii. - Cd uptake processes are biological processes in S. herzogii and adsorption, chelation and ionic exchange are in P. stratiotes, whereas Cr uptake processes in both macrophytes are adsorption, chelation and ion exchange.

  20. Assessment of the Potential Biological Activity of Low Molecular Weight Metabolites of Freshwater Macrophytes with QSAR

    Science.gov (United States)

    Fedorova, Elena V.; Krylova, Julia V.

    2016-01-01

    The paper focuses on the assessment of the spectrum of biological activities (antineoplastic, anti-inflammatory, antifungal, and antibacterial) with PASS (Prediction of Activity Spectra for Substances) for the major components of three macrophytes widespread in the Holarctic species of freshwater, emergent macrophyte with floating leaves, Nuphar lutea (L.) Sm., and two species of submergent macrophyte groups, Ceratophyllum demersum L. and Potamogeton obtusifolius (Mert. et Koch), for the discovery of their ecological and pharmacological potential. The predicted probability of anti-inflammatory or antineoplastic activities above 0.8 was observed for twenty compounds. The same compounds were also characterized by high probability of antifungal and antibacterial activity. Six metabolites, namely, hexanal, pentadecanal, tetradecanoic acid, dibutyl phthalate, hexadecanoic acid, and manool, were a part of the major components of all three studied plants, indicating their high ecological significance and a certain universalism in their use by various species of water plants for the implementation of ecological and biochemical functions. This report underlines the role of identified compounds not only as important components in regulation of biochemical and metabolic pathways and processes in aquatic ecological systems, but also as potential pharmacological agents in the fight against different diseases. PMID:27200207

  1. Microbial communities in marine sediments modify success of an invasive macrophyte.

    Science.gov (United States)

    Gribben, Paul E; Nielsen, Shaun; Seymour, Justin R; Bradley, Daniel J; West, Matthew N; Thomas, Torsten

    2017-08-29

    Invasive plants have extensive impacts on ecosystem function and biodiversity globally. Our inability to manage invasive species stems in part from a lack of understanding of the processes that control their successful establishment and spread. To date, studies have largely considered how above-ground processes control native/invasive plant interactions. Emerging research from terrestrial and wetland ecosystems demonstrates that below-ground processes under microbial control can determine the outcome of interactions between native and invasive plants. Whether sediment microbes modify the success of invasive macrophytes in marine ecosystems is untested, despite marine sediment microbes controlling many ecological processes (e.g. nutrient cycling) comparable to those in terrestrial ecosystems. We first show that sediment bacterial communities differ between the native seagrass Zostera capricorni and the invasive alga Caulerpa taxifolia and that those differences relate to functional changes in sulfur cycling between the macrophytes. Second, by experimentally manipulating the microbial communities we show that intact microbial communities in Z. capricorni sediments provide biotic resistance by reducing C. taxifolia fragment growth 119% compared to when they are inactive, and intact microbial communities in C. taxifolia sediments have positive feedbacks by increasing fragment growth 200%. Thus, similar to terrestrial ecosystems, microorganisms appear to indirectly control the success of invasive macrophytes in marine ecosystems.

  2. Habitat selection by three littoral zone fishes: effects of predation pressure, plant density and macrophyte type

    Science.gov (United States)

    Chick, J.H.; McIvor, C.C.

    1997-01-01

    We conducted laboratory experiments which demonstrated that three littoral zone fishes differentially selected among three macrophytes when seeking refuge from predation. In the presence of a predator (a juvenile Micropterus salmoides), mosquitofish (Gambusia holbrooki), sailfin mollies (Poecilia latipinna). and dollar sunfish (Lepomis marginatus) displayed ferential use of four tank areas containing patches of either Hydrilla verticillata, Potamogeton illinoensis, Panicum hemitomon, or no plants. Patterns habitat selection, and the consistency of these patterns among replicates, differed among the three fishes and among three plant-density treatments - natural (each macrophyte presented at its mean field density), equal (all three macrophytes at the same density), and control (no plants). Selection for H. verticillata by mosquitofish was significant for both the equal and natural treatments, and thus was not caused by differences in plant density alone. Sailfin mollies displayed significant selection for H. verticillata only in the natural plant-density treatments. Dollar sunfish showed less consistent habitat selection than either mosquitofish or sailfin mollies. Significant habitat selection was not found in the absence of a predator, and there was no evidence for lection among the tank areas in control treatments. Patterns of habitat selection by the three fishes in our laboratory study corresponded to observed habitat use in Lake Okeechobee.

  3. An invasion risk map for non-native aquatic macrophytes of the Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Argantonio Rodríguez-Merino

    2017-05-01

    Full Text Available Freshwater systems are particularly susceptible to non-native organisms, owing to their high sensitivity to the impacts that are caused by these organisms. Species distribution models, which are based on both environmental and socio-economic variables, facilitate the identification of the most vulnerable areas for the spread of non-native species. We used MaxEnt to predict the potential distribution of 20 non-native aquatic macrophytes in the Iberian Peninsula. Some selected variables, such as the temperature seasonality and the precipitation in the driest quarter, highlight the importance of the climate on their distribution. Notably, the human influence in the territory appears as a key variable in the distribution of studied species. The model discriminated between favorable and unfavorable areas with high accuracy. We used the model to build an invasion risk map of aquatic macrophytes for the Iberian Peninsula that included results from 20 individual models. It showed that the most vulnerable areas are located near to the sea, the major rivers basins, and the high population density areas. These facts suggest the importance of the human impact on the colonization and distribution of non-native aquatic macrophytes in the Iberian Peninsula, and more precisely agricultural development during the Green Revolution at the end of the 70’s. Our work also emphasizes the utility of species distribution models for the prevention and management of biological invasions.

  4. Epiphytic bacterial communities on two common submerged macrophytes in Taihu Lake: diversity and host-specificity

    Institute of Scientific and Technical Information of China (English)

    HE Dan; REN Lijuan; WU Qinglong

    2012-01-01

    Leaves of terrestrial and aquatic plants are home to a wide diversity of bacterial species.However,the diversity and variability of epiphytic bacteria on their submerged plant hosts remains poorly understood.We investigated the diversity and composition of epiphytic bacteria from two common submerged macrophytes:Vallisneria natans and Hydrilla verticillata in Taihu Lake,Jiangsu,China,using methods of terminal restriction fragment length polymorphisms (T-RFLP) and clone library analyses targeted at bacterial 16S rRNA genes.The results show that:(1) the libraries of the two waterweeds contain wide phylogenetic distribution of bacteria,and that the sequences of the two libraries can be separated into 93 OTUs (at 97% similar value); (2) Betaproteobacteria,including Burkholderiales,was the most abundant bacterial group on both plants.Cyanobacteria and Gammaproteobacteria were the second largest groups on V.natans and H.verticillata,respectively.Both clone libraries included some sequences related to those of methanotrophs and nitrogen-fixing bacteria; (3) Cluster analysis of the T-RFLP profiles showed two distinct clusters corresponding to the two plant populations.Both ANOSIM of the T-RFLPdata and Libshuff analysis of the two clone libraries indicated a significant difference in epiphytic bacterial communities between the two plants.Therefore,the epiphytic bacterial communities on submerged macrophytes appear to be diverse and host-specific,which may aid in understanding the ecological functions of submerged macrophytes in general.

  5. Foreign Funds for City Banks

    Institute of Scientific and Technical Information of China (English)

    WANGPEI

    2005-01-01

    The rather straightforward restructuring of the Bank of Beijing became more arresting in January after Deutsche Bank was reported to be competing with its Dutch rival ING to purchase a stake in the local city commercial bank.

  6. Competition in investment banking

    Directory of Open Access Journals (Sweden)

    Katrina Ellis

    2011-01-01

    Full Text Available We construct a comprehensive measure of overall investment banking competitiveness for follow-on offerings that aggregates the various dimensions of competition such as fees, pricing accuracy, analyst recommendations, distributional abilities, market making prowess, debt offering capabilities, and overall reputation. The measure allows us to incorporate trade-offs that investment banks may use in competing for new or established clients. We find that firms who switch to similar-quality underwriters enjoy more intense competition among investment banks which manifests in lower fees and more optimistic recommendations. Investment banks do compete vigorously for some clients, with the level of competition related to the likelihood of gaining or losing clients. Finally, investment banks not performing up to market norms are more likely to be dropped in the follow-on offering. In contrast, firms who seek a higher reputation underwriter face relatively non-competitive markets.

  7. Micropropagation, seed propagation and germplasm bank of Mandevilla velutina (Mart. Woodson Micropropagação, propagação por sementes e banco de germoplasma de Mandevilla velutina (Mart. Woodson

    Directory of Open Access Journals (Sweden)

    Ronaldo Biondo

    2007-06-01

    Full Text Available Mandevilla velutina (Mart. Woodson (Apocynaceae is a medicinal plant species with antivenom properties, native from Brazilian Savanna regions (Cerrado, which due to overexploitation and habitat deforestation is in danger of extinction. As an initiative for conserving this endangered but economically important plant species, a micropropagation protocol was developed and genotypes were stored in the Germplasm Bank "Cerrado In vitro". For the in vitro propagation of M. velutina, nodal segments were inoculated on Murashige and Skoog (MS medium supplemented with different concentrations of BA, Zeatin, 2ip, DTT and TDZ. Best multiplication ratio was achieved when to the medium 0.44 µM BA, ranging 1: 6.7, were added. Plantlets cultured on MS/2 medium supplemented with 26.85 µM NAA rooted successfully (50.5%. Although rooted and un-rooted plantlets acclimatized to soil conditions, great losses were observed within un-rooted plantlets, while the rooted presented 100 % survival. It was possible to maintain 43% of the M. velutina germplasm under healthy conditions for six months, with no subcultures, using the MS medium supplemented with 2% sucrose, 13.8 mM spermidine, 2% sorbitol and 2% dextrose.Mandevilla velutina (Mart. Woodson (Apocynaceae é uma planta medicinal de espécie nativa de regiões do Cerrado brasileiro com propriedades anti-ofídicas. Devido a alta exploração e devastação deste bioma, M. velutina está em perigo de extinção. Como uma iniciativa para a conservação desta espécie ameaçada e economicamente importante, um protocolo de micropropagação foi desenvolvido e genótipos foram colocados no Banco de Germoplasma "Cerrado In vitro". Para a propagação in vitro de M. velutina, segmentos nodais foram inoculados no meio Murashige and Skoog (MS suplementado com diferentes concentrações de BA, zeatina, 2ip, DTT e TDZ. A melhor resposta de multiplicação foi obtida em meio suplementado com 0.44 µM BA na razão 1: 6.7. Pl

  8. 间伐强度对秦岭南坡栓皮栎种子库及实生苗生长的影响%Effects of thinning intensity on the seed bank and seedling growth of Quercus variabilis on the south slope of Qinling Mountains, Northwest China

    Institute of Scientific and Technical Information of China (English)

    冉然; 张文辉; 周建云; 何景峰

    2013-01-01

    In August-November 2010 and August 2011,and taking the pure Quercus variabilis forests under close-to-natural management of different thinning intensity (30%,20%,and 10%) in Shangluo district of south slope of Qinling Mountains as the object,an investigation was conducted on the seed amount of seed bank,the survival rate and growth status of seedlings,and their relationships with environmental factors 4-5 years after thinning.As compared with the control,the seed amount in the seed bank of 10%,20%,and 30% thinning plots increased by 2.0%,21.1%,and 34.8%,respectively in the fourth year after thinning,and the 1-year-old seedlings amount increased by 28.5%,99.7%,and 122.2%,respectively in the next year.The survival rate of the seedlings in the 10%,20%,and 30% thinning plots was increased by 25.5%,235.7%,and 480.0%,respectively in the fifth year after thinning.Thinning improved the light,temperature,soil moisture,and soil nutrient conditions in the forests,which promoted the heightand new shoot growth and the leaf area index of each age seedlings.The three growth indices also increased with increasing thinning intensity.In the Q.variabilis forest with a canopy density of ≥0.85,the thinning intensity 30% (canopy density 0.6) was most conducive to the seed germination and seedling growth.%2010年8-11月和2011年8月,以秦岭南坡商洛地区近自然经营的不同间伐强度(30%、20%和10%)下的栓皮栎纯林为对象,分析了间伐4~5年后栓皮栎种子库的种子数量,实生苗的存活率和生长状况,及其与环境因子的关系.结果表明:与对照相比,间伐后第4年,间伐10%、20%和30%强度下种子库中的种子总数分别增加了2.0%、21.1%和34.8%,翌年1年生实生苗数量分别增加了28.5%、99.7%和122.2%;间伐5年后,间伐10%、20%和30%样地内实生苗的存活率分别提高了25.5%、235.7%和480.0%.间伐使林地的光照、温度、土

  9. Seed ecology of Bromus sterilis L.

    Directory of Open Access Journals (Sweden)

    Žďárková, Veronika

    2014-02-01

    Full Text Available Bromus sterilis L. (barren brome has become a troublesome weed of winter cereals in reduced tillage systems, mainly in South and North America, middle and Western Europe. In the Czech Republic, its importance has increased dramatically over the past 10 years. Barren brome is reported as a problem weed in other winter crops such as oil seed rape, in vineyards and in other cultivated places. In this study, the dormancy and germination under different temperatures, water and light regimes were investigated. Emergence from different depths and persistence in the soil profile were investigated under field conditions. The seeds of Bromus sterilis showed broad ecological valence to hydrothermal factors germinating in the wide range of 5 to 35 °C. Similarly, no strong effect on the germination in an environment with low water potential was observed. The response to light at various temperatures showed that seeds germinated better in darkness. The emergence declined significantly with burial depth (under 40 mm. The loss of primary dormancy was rapid in time and only 50% of the seeds germinated within 8 weeks after collecting from maternal plants. The seeds were not able to survive in the soil seed bank for a longer time and fall seeds lost viability 1 year after burial in a soil profile.

  10. Trace element concentrations in freshwater mussels and macrophytes as related to those in their environment

    Directory of Open Access Journals (Sweden)

    Gian Maria BEONE

    2003-02-01

    Full Text Available This study was primarily designed to contribute to the debate "Do accumulator species reflect the element contamination level of their environment?" This research was carried out: 1 to know the distribution of 15 trace elements and calcium in shell and soft tissues of three species of freshwater mussels and macrophytes; 2 to compare the accumulation capacity of each trace element by mussels and by eight species of macrophytes and 3 to test the relationships between the metal concentrations in the mussels and macrophytes and those in water and sediments. The variability of element residues in the mussels is the major limit to accumulator monitoring. The most important causes are: seasonal cycle, physical environment and biological factors such as the size, age and growth rate. This research was designed to eliminate the consequence of variability deriving from the season and the environment. To this end the mussels and macrophytes were collected at the same time from the same habitat: Ranco Bay, Lago Maggiore, Northern Italy. In addition, the element concentrations in more size-classes of the most abundant mussel species (Unio pictorum and Dreissena polymorpha were measured. Trace elements were analyzed by Inductive Coupled Plasma-Mass Spectrometry (ICP-MS. By arranging the data in sequences of decreasing element concentrations in the organisms as well as in water and sediments, we were able to compare the accumulating ability of the tested species and evaluate their capacity to reflect environmental availability. Neither the sequences in the shell nor those in the tissues were similar to the sequence in the water. The differences between the sequences of the mussel tissues and those of the sediments were less striking than those between shells and sediments. Similar results were obtained by macrophytes. In conclusion, the results of this study (which mimics the monitoring practice prove that bioaccumulators cannot be used to evaluate the

  11. Biodiversity patterns of macrophyte and macroinvertebrate communities in two lagoons of Western Greece.

    Science.gov (United States)

    Fyttis, G.; Reizopoulou, S.; Papastergiadou, E.

    2012-04-01

    Aquatic macrophytes and benthic macroinvertebrates were studied seasonally (Spring, Autumn, Summer) between the years 2009 - 2011 in two coastal lagoons (Kotychi and Prokopos) located in Peloponnese, Greece, in order to investigate spatial and temporal biodiversity trends related to hydrological processes (degree of confinement, nitrates, phosphates, chl-a, total suspended materials, light irradiance, pH, salinity, temperature and dissolved oxygen). Kotychi lagoon presents a better communication with the sea, while Prokopos has a high degree of confinement. Both ecosystems seasonally receive freshwater input from streams. The submerged aquatic macrophytes constituted a major component of the ecosystems studied. In total, 22 taxa of aquatic macrophytes (angiosperms and macroalgae), 16 taxa for Kotychi (2 Rhodophyta, 8 Chlorophyta, 5 Magnoliophyta, 1 Streptophyta) and 14 taxa for Prokopos (1 Rhodophyta, 5 Chlorophyta, 5 Magnoliophyta, 3 Streptophyta) were found. Ruppia cirrhosa, and Potamogeton pectinatus were dominant in both lagoons. Kotychi lagoon was also dominated by Zostera noltii and Prokopos by Zannichellia pallustris ssp. pedicellata, while the biomass of aquatic species peaked during the summer periods, in both lagoons. The total number of macroinvertebrates found in the lagoons was 28 taxa for Kotychi and 19 for Prokopos. Chironomidae were dominant in both lagoons, while Kotychi was also dominated by Lekanesphaera monodi and Monocorophium insidiosum, and Prokopos by Ostracoda and Lekanesphaera monodi. Benthic diversity ranged from 1.33 to 2.57 in Kotychi and from 0.67 to 2.48 in Prokopos. Species richness, diversity, and abundance of benthic macroinvertebrates were strongly related to aquatic vegetation and to the degree of communication with the marine environment. Moreover, species richness and abundance of both macrophytes and macroinvertebrates were mainly dependent on depth, temperature, pH and concentration of total suspended materials (TSM). Results

  12. [Sorbus pohuashanensis seed dispersal and germination and their relationships with population natural regeneration].

    Science.gov (United States)

    Xu, Jian-wei; Shen, Hai-long; Zhang, Xiu-liang; Zhang, Peng; Huang, Jian

    2010-10-01

    Sorbus pohuashanensis is an important non-timber tree species in Northeast China, but poor in natural regeneration via seed dispersal. In this paper, a field observation was made on the seed dispersal of S. pohuashanensis, its seedling emergence, and soil seed bank, aimed to study the factors affecting the natural regeneration of this tree species. There were 96.1% of naturally dispersed S. pohuashanensis seeds distributed within the range of 2 m around the stock tree, and 97.0% of the seeds in soil seed bank distributed in litter layer and 0-2 cm surface soil. The seed quantity in soil seed bank differed greatly with seasons, being the maximum [(257.7 +/- 69.2) seeds per square meter] in early November in the year of seed dispersal, and the minimum [only (2.9 +/- 2.9) seeds per square meter] in next July. Temperature was not the limiting factor affecting the seedling emergence of S. pohuashanensis [at 0 degrees C-5 degrees C, the seedling emergence percentage could reach (67.5 +/- 6.6)%], but strongly affected the seedling emergence rate. The most proper soil moisture content for the seedling emergence was 50% , under which, the seedling emergence percentage could reach (74.7 +/- 4.2)%. When the soil moisture content was up to 60%, the seedling mortality was the lowest (32.6% +/- 0.6%). All the results suggested that the seed dispersal pattern of S. pohuashanensis and the spatiotemporal dynamics of soil seed bank could affect the seedling emergence of the tree species, and further, affect the population natural regeneration of S. pohuashanensis via seed dispersal.

  13. Environment sensing in spring-dispersed seeds of a winter annual Arabidopsis influences the regulation of dormancy to align germination potential with seasonal changes.

    Science.gov (United States)

    Footitt, Steven; Clay, Heather A; Dent, Katherine; Finch-Savage, William E

    2014-05-01

    Seed dormancy cycling plays a crucial role in the lifecycle timing of many plants. Little is known of how the seeds respond to the soil seed bank environment following dispersal in spring into the short-term seed bank before seedling emergence in autumn. Seeds of the winter annual Arabidopsis ecotype Cvi were buried in field soils in spring and recovered monthly until autumn and their molecular eco-physiological responses were recorded. DOG1 expression is initially low and then increases as dormancy increases. MFT expression is negatively correlated with germination potential. Abscisic acid (ABA) and gibberellin (GA) signalling responds rapidly following burial and adjusts to the seasonal change in soil temperature. Collectively these changes align germination potential with the optimum climate space for seedling emergence. Seeds naturally dispersed to the soil in spring enter a shallow dormancy cycle dominated by spatial sensing that adjusts germination potential to the maximum when soil environment is most favourable for germination and seedling emergence upon soil disturbance. This behaviour differs subtly from that of seeds overwintered in the soil seed bank to spread the period of potential germination in the seed population (existing seed bank and newly dispersed). As soil temperature declines in autumn, deep dormancy is re-imposed as seeds become part of the persistent seed bank. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  14. Bank Specific and Macroeconomics Dynamic Determinants of Credit Risk in Islamic Banks and Conventional Banks

    OpenAIRE

    Waeibrorheem Waemustafa; Suriani Sukri

    2015-01-01

    The study analyzes macroeconomic and bank specific determinants of credit risk in Islamic and Conventional Banks. Multivariate Regression analysis is applied on the sample of 15 conventional banks and 13 Islamic Banks in Malaysia over the period between 2000 and 2010. The finding shows that the banks specific determinants of credit risk are uniquely influenced the credit risk formation of Islamic and Conventional banks. The study found that risky sector financing; regulatory capital (REGCAP) ...

  15. GenBank

    Science.gov (United States)

    Benson, Dennis A.; Cavanaugh, Mark; Clark, Karen; Karsch-Mizrachi, Ilene; Lipman, David J.; Ostell, James; Sayers, Eric W.

    2017-01-01

    GenBank® (www.ncbi.nlm.nih.gov/genbank/) is a comprehensive database that contains publicly available nucleotide sequences for 370 000 formally described species. These sequences are obtained primarily through submissions from individual laboratories and batch submissions from large-scale sequencing projects, including whole genome shotgun (WGS) and environmental sampling projects. Most submissions are made using the web-based BankIt or the NCBI Submission Portal. GenBank staff assign accession numbers upon data receipt. Daily data exchange with the European Nucleotide Archive (ENA) and the DNA Data Bank of Japan (DDBJ) ensures worldwide coverage. GenBank is accessible through the NCBI Nucleotide database, which links to related information such as taxonomy, genomes, protein sequences and structures, and biomedical journal literature in PubMed. BLAST provides sequence similarity searches of GenBank and other sequence databases. Complete bimonthly releases and daily updates of the GenBank database are available by FTP. Recent updates include changes to policies regarding sequence identifiers, an improved 16S submission wizard, targeted loci studies, the ability to submit methylation and BioNano mapping files, and a database of anti-microbial resistance genes. PMID:27899564

  16. Soundness of Ethiopian Banks

    Directory of Open Access Journals (Sweden)

    Hamdu Kedir Mohammed

    2015-06-01

    Full Text Available A well-functioning financial institution will sustain a countries economic development and play a great role in reduction of poverty. One of the major participants in the financial institution is the banking industry. However, the mal-functioning of the banking system can be extremely costly to the real economy. As Bank is one of the participants and major key player in the financial institutions, it needs a continuous assessment by its supervisory and management. Mere ratio analyses are commonly used Performance measurement among the banking industry in Ethiopia. Nonetheless, these financial ratios are more of traditional as well as partial measurements. As such this study conducted using CAMEL framework set by bank for international settlement. The study takes secondary data which are gathered from audited annual reports of all banks. The result shows CAMEL framework is the best fit measurement for Ethiopian Banks and it give a comprehensive result which is very helpful for the governor to set a well determined policy and procedure.

  17. Seed Treatment. Bulletin 760.

    Science.gov (United States)

    Lowery, Harvey C.

    This manual gives a definition of seed treatment, the types of seeds normally treated, diseases and insects commonly associated with seeds, fungicides and insecticides used, types of equipment used for seed treatment, and information on labeling and coloring of treated seed, pesticide carriers, binders, stickers, and safety precautions. (BB)

  18. PERBANDINGAN PENGHASILAN TABUNGAN MUDHARABAH NASABAH BANK SYARIAH (Studi Kasus pada Bank Syariah Mandiri, Bank Negara Indonesia Syariah, dan Bank Muamalat Indonesia di Makassar)

    OpenAIRE

    ALIMULA, YULIANA

    2014-01-01

    2014 Perbandingan Penghasilan Tabungan Mudharabah Nasabah Bank Syariah (Studi Kasus pada Bank Syariah Mandiri, Bank Negara Indonesia Syariah, dan Bank Muamalat Indonesia di Makassar) Profit Sharing Comparison of Mudharabah Saving of Islamic Banking (A Case Study at Bank Syariah Mandiri, Bank Negara Indonesia Syariah, and Bank Muamalat Indonesia in Makassar) Yuliana Alimula Alimuddin Muhammad Ashari Penelitian ini bertujuan un...

  19. Bank selection and customers’ perception of banks in Malaysia

    OpenAIRE

    Norhazlin Ismail; Zarehan Selamat; Ong Hway Boon

    2004-01-01

    The process customers go through in choosing a bank has been studied for several decades using different approaches. Understanding the needs and analyzing how the customers select their banks are crucial steps towards the improvement of customer satisfaction. In this study, an attempt is made to identify the determinants of bank selection and customers’ perception of banks in Malaysia.

  20. The role of pH in structuring communities of Maine wetland macrophytes and chironomid larvae (Diptera)

    Science.gov (United States)

    Woodcock, T.S.; Longcore, J.R.; McAuley, D.G.; Mingo, T.M.; Bennatti, C.R.; Stromborg, K.L.

    2005-01-01

    Aquatic vascular plants, or macrophytes, are an important habitat component for many wetland organisms, and larvae of chironomid midges are ubiquitous components of wetland fauna. Many chironomids are primary consumers of algae and detritus and form an essential energetic link between allochthonous and autochthonous primary production and higher trophic levels, while others are predators and feed on smaller invertebrates. Live macrophytes serve mostly as habitat, whereas plant detritus serves as both habitat and as a food source. Assemblages of macrophytes and chironomid larvae were surveyed in ten Maine wetlands, five with low pH (5.5), and explained in terms of physical and chemical habitat variables. Macrophyte richness was significantly greater, and richness of chironomid larvae was lower, in low pH wetlands. There was no difference in chironomid abundance related to pH. However, community structure was related to pH, suggesting that competitive dominance of a few taxa was responsible for lower richness in low pH wetlands, whereas competition was weaker in high pH wetlands, making coexistence of more chironomid taxa possible. An examination of individual chironomid taxa by stepwise multiple regression showed that distribution of most taxa was controlled by water chemistry variables and macrophyte habit (i.e., floating, submergent).