WorldWideScience

Sample records for grass roots community

  1. Grass Rooting the System

    Science.gov (United States)

    Perlman, Janice E.

    1976-01-01

    Suggests a taxonomy of the grass roots movement and gives a general descriptive over view of the 60 groups studied with respect to origin, constituency, size, funding, issues, and ideology. (Author/AM)

  2. Metagenomics at Grass Roots

    Indian Academy of Sciences (India)

    CAMERA (Community Cyber-infrastructure for Advanced Mi- crobial Ecology .... Acidobacteria known to metabolize a variety of car- bon sources .... [7] J Nesme et al., Back to the future of soil metagenomics, Frontiers in Microbi- ology, Vol.7 ...

  3. Metagenomics at Grass Roots

    Indian Academy of Sciences (India)

    Metagenomics is a robust, interdisciplinary approach for studyingmicrobial community composition, function, and dynamics.It typically involves a core of molecular biology, microbiology,ecology, statistics, and computational biology. Excitingoutcomes anticipated from these studies include unravelingof complex interactions ...

  4. Drought and host selection influence microbial community dynamics in the grass root microbiome

    Science.gov (United States)

    Through 16S rRNA gene profiling across two distinct watering regimes and two developmental time points, we demonstrate that there is a strong correlation between host phylogenetic distance and the microbiome dissimilarity within root tissues, and that drought weakens this correlation by inducing con...

  5. Rural Revitalization in New Mexico: A Grass Roots Initiative Involving School and Community

    Science.gov (United States)

    Pitzel, Gerald R.; Benavidez, Alicia C.; Bianchi, Barbara C.; Croom, Linda L.; de la Riva, Brandy R.; Grein, Donna L.; Holloway, James E.; Rendon, Andrew T.

    2007-01-01

    The Rural Education Bureau of the New Mexico Public Education Department has established a program to address the special needs of schools and communities in the extensive rural areas of the state. High poverty rates, depopulation and a general lack of viable economic opportunity have marked rural New Mexico for decades. The program underway aims…

  6. Interactions of technology and society: Impacts of improved airtransport. A study of airports at the grass roots. [in rural communities

    Science.gov (United States)

    Laporte, T.; Rosenthal, S.; Ross, S.; Lee, K. N.; Levine, E.

    1977-01-01

    The feasibility of applying a particular conception of technology and social change to specific examples of technological development was investigated. The social and economic effects of improved airport capabilities on rural communities were examined. Factors which led to the successful implementation of a plan to construct sixty small airports in Ohio are explored and implications derived for forming public policies, evaluating air transportation development, and assessing technology.

  7. Asymmetric response of root-associated fungal communities of an arbuscular mycorrhizal grass and an ectomycorrhizal tree to their coexistence in primary succession

    Czech Academy of Sciences Publication Activity Database

    Knoblochová, T.; Kohout, Petr; Püschel, D.; Doubková, P.; Frouz, J.; Cajthaml, T.; Kukla, J.; Vosátka, M.; Rydlová, J.

    2017-01-01

    Roč. 27, č. 8 (2017), s. 775-789 ISSN 0940-6360 R&D Projects: GA ČR GA13-10377S Institutional support: RVO:61388971 Keywords : Arbuscular mycorrhiza * Ectomycorrhiza * Root-associated fungal communities Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.047, year: 2016

  8. Grass-roots approach: developing qualified nuclear personnel

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Nuclear power plants experiencing personnel recruitment problems are trying a grass-roots approach to increase the manpower pool. The Philadelphia Electric Co. and the Toledo Edison Co. are working with local educational institutions to offer nuclear-technology training specific to the needs of nuclear plants. The utilities' investment covers much of the cost of instruction as well as continued training for employees

  9. Molecular Physiology of Root System Architecture in Model Grasses

    Science.gov (United States)

    Hixson, K.; Ahkami, A. H.; Anderton, C.; Veličković, D.; Myers, G. L.; Chrisler, W.; Lindenmaier, R.; Fang, Y.; Yabusaki, S.; Rosnow, J. J.; Farris, Y.; Khan, N. E.; Bernstein, H. C.; Jansson, C.

    2017-12-01

    Unraveling the molecular and physiological mechanisms involved in responses of Root System Architecture (RSA) to abiotic stresses and shifts in microbiome structure is critical to understand and engineer plant-microbe-soil interactions in the rhizosphere. In this study, accessions of Brachypodium distachyon Bd21 (C3 model grass) and Setaria viridis A10.1 (C4 model grass) were grown in phytotron chambers under current and elevated CO2 levels. Detailed growth stage-based phenotypic analysis revealed different above- and below-ground morphological and physiological responses in C3 and C4 grasses to enhanced CO2 levels. Based on our preliminary results and by screening values of total biomass, water use efficiency, root to shoot ratio, RSA parameters and net assimilation rates, we postulated a three-phase physiological mechanism, i.e. RootPlus, BiomassPlus and YieldPlus phases, for grass growth under elevated CO2 conditions. Moreover, this comprehensive set of morphological and process-based observations are currently in use to develop, test, and calibrate biophysical whole-plant models and in particular to simulate leaf-level photosynthesis at various developmental stages of C3 and C4 using the model BioCro. To further link the observed phenotypic traits at the organismal level to tissue and molecular levels, and to spatially resolve the origin and fate of key metabolites involved in primary carbohydrate metabolism in different root sections, we complement root phenotypic observations with spatial metabolomics data using mass spectrometry imaging (MSI) methods. Focusing on plant-microbe interactions in the rhizosphere, six bacterial strains with plant growth promoting features are currently in use in both gel-based and soil systems to screen root growth and development in Brachypodium. Using confocal microscopy, GFP-tagged bacterial systems are utilized to study the initiation of different root types of RSA, including primary root (PR), coleoptile node axile root (CNR

  10. Arbuscular mycorrhizal assemblages in native plant roots change in the presence of invasive exotic grasses

    Science.gov (United States)

    Hawkes, C.V.; Belnap, J.; D'Antonio, C.; Firestone, M.K.

    2006-01-01

    Plant invasions have the potential to significantly alter soil microbial communities, given their often considerable aboveground effects. We examined how plant invasions altered the arbuscular mycorrhizal fungi of native plant roots in a grassland site in California and one in Utah. In the California site, we used experimentally created plant communities composed of exotic (Avena barbata, Bromus hordeaceus) and native (Nassella pulchra, Lupinus bicolor) monocultures and mixtures. In the Utah semi-arid grassland, we took advantage of invasion by Bromus tectorum into long-term plots dominated by either of two native grasses, Hilaria jamesii or Stipa hymenoides. Arbuscular mycorrhizal fungi colonizing roots were characterized with PCR amplification of the ITS region, cloning, and sequencing. We saw a significant effect of the presence of exotic grasses on the diversity of mycorrhizal fungi colonizing native plant roots. In the three native grasses, richness of mycorrhizal fungi decreased; in the native forb at the California site, the number of fungal RFLP patterns increased in the presence of exotics. The exotic grasses also caused the composition of the mycorrhizal community in native roots to shift dramatically both in California, with turnover of Glomus spp., and Utah, with replacement of Glomus spp. by apparently non-mycorrhizal fungi. Invading plants may be able to influence the network of mycorrhizal fungi in soil that is available to natives through either earlier root activity or differential carbon provision compared to natives. Alteration of the soil microbial community by plant invasion can provide a mechanism for both successful invasion and the resulting effects of invaders on the ecosystem. ?? Springer 2006.

  11. Cadre Building to Strengthen Grass Root Governance

    Directory of Open Access Journals (Sweden)

    Ranjit Kumar Mohanty

    2010-09-01

    Full Text Available The long drawn-out debate over the very survival of the planet has stimulated people worldwide to think about the role of education in achieving sustainable development (SD. Over the years, the public in general and policy makers in particular have realised the value of education in achieving SD. The journey from “Education about Sustainable Development” to “Education for Sustainable Development (ESD” has been an achievement worthy of recognition. The global focus on education as a key tool for achieving SD has brought a degree of clarity of understanding to the problem of sustainability, which is perceived as being quite complex. It has helped people in general to understand where to begin addressing concerns about the end of the world, should it come more rapidly than they imagined.  This paper describes an experiment that uses an approach of developing a cadre of young entrepreneurs called Community Entrepreneurs (CEs to facilitate the process of SD in tribal areas of Gujarat. The concept which has a historical and Gandhian affiliation looks at Humans as the core of any change process and how education plays an important role in bringing sustainability in terms of social, environmental, socio-cultural and economic aspects. The transformation is not only limited to aspects mentioned above but elucidates various changes brought in the community as a process of empowerment. The paper describes the journey from awareness, to action, to empowerment, to decision making. The paper also discusses the road ahead for such an intervention to be sustainable.Dans le monde entier, le débat de longue date sur la survie de la planète a encouragé les gens à réfléchir sur le rôle que peut jouer l’éducation pour arriver au développement durable (DD. Au fil des années, le public en général, et les responsables politiques en particulier, ont pris conscience de l’importance de l’éducation pour atteindre cet objectif. Le parcours de

  12. Root proliferation in native perennial grasses of arid Patagonia, Argentina

    Institute of Scientific and Technical Information of China (English)

    Yanina A. TORRES; Mara M. MUJICA; Sandra S. BAIONI; Jos ENTO; Mara N. FIORETTI; Guillermo TUCAT; Carlos A. BUSSO; Oscar A. MONTENEGRO; Leticia ITHURRART; Hugo D. GIORGETTI; Gustavo RODRGUEZ; Diego BENTIVEGNA; Roberto E. BREVEDAN; Osvaldo A. FERNNDEZ

    2014-01-01

    Pappophorum vaginatum is the most abundant C4 perennial grass desirable to livestock in rangelands of northeastern Patagonia, Argentina. We hypothesized that (1) defoliation reduce net primary productivity, and root length density and weight in the native species, and (2) root net primary productivity, and root length density and weight, are greater in P. vaginatum than in the other, less desirable, native species (i.e., Aristida spegazzinii, A. subulata and Sporobolus cryptandrus). Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons. Root proliferation was measured using the cylinder method. Cylindrical, iron structures, wrapped up using nylon mesh, were buried diagonally from the periphery to the center on individual plants. These structures, initially filled with soil without any organic residue, were dug up from the soil on 25 April 2008, after two successive defoliations in mid-spring 2007. During the second growing season (2008-2009), cylinders were destructively harvested on 4 April 2009, after one or two defoliations in mid-and/or late-spring, respectively. Roots grown into the cylinders were obtained after washing the soil manually. Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice, which supported the first hypothesis. The greater root net primary productivity, root length den-sity and weight in P. vaginatum than in the other native species, in support of the second hypothesis, could help to explain its greater abundance in rangelands of Argentina.

  13. Interaction between Vetiver Grass Roots and Completely Decomposed Volcanic Tuff under Rainfall Infiltration Conditions

    Directory of Open Access Journals (Sweden)

    Ling Xu

    2018-01-01

    Full Text Available The important role of vetiver grass roots in preventing water erosion and mass movement has been well recognized, though the detailed influence of the grass roots on soil has not been addressed. Through planting vetiver grass at the Kadoorie Farm in Hong Kong and leaving it to grow without artificial maintenance, the paper studies the influence of vetiver grass roots on soil properties and slope stability. Under the natural conditions of Hong Kong, growth of the vetiver grass roots can reach 1.1 m depth after one and a half year from planting. The percentage of grain size which is less than 0.075 mm in rooted soil is more than that of the nonrooted soil. Vetiver grass roots can reduce soil erosion by locking the finer grain. The rooted soil of high finer grain content has a relatively small permeability. As a result, the increase in water content is therefore smaller than that of nonrooted soil in the same rainfall conditions. Shear box test reveals that the vetiver grass roots significantly increased the peak cohesion of the soil from 9.3 kPa to 18.9 kPa. The combined effects of grass roots on hydrological responses and shearing strength significantly stabilize the slope in local rainfall condition.

  14. Asymmetric response of root-associated fungal communities of an arbuscular mycorrhizal grass and an ectomycorrhizal tree to their coexistence in primary succession

    Czech Academy of Sciences Publication Activity Database

    Knoblochová, Tereza; Kohout, Petr; Püschel, David; Doubková, Pavla; Frouz, J.; Cajthaml, T.; Kukla, J.; Vosátka, Miroslav; Rydlová, Jana

    2017-01-01

    Roč. 27, č. 8 (2017), s. 775-789 ISSN 0940-6360 R&D Projects: GA ČR GA13-10377S Institutional support: RVO:67985939 Keywords : mycorrhiza * fungal communities * succession Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 3.047, year: 2016

  15. Revisiting community case management of childhood pneumonia: perceptions of caregivers and grass root health providers in Uttar Pradesh and Bihar, northern India.

    Directory of Open Access Journals (Sweden)

    Shally Awasthi

    Full Text Available Community-acquired pneumonia (CAP is the leading cause of under-five mortality globally with almost one-quarter of deaths occurring in India.To identify predisposing, enabling and service-related factors influencing treatment delay for CAP in rural communities of two states in India. Factors investigated included recognition of danger signs of CAP, health care decision making, self-medication, treatment and referral by local practitioners, and perceptions about quality of care.Qualitative research employing case studies (CS of care-seeking, key informant interviews (KII, semi-structured interviews (SSI and focus group discussions (FGD with both video presentations of CAP signs, and case scenarios. Interviews and FGDs were conducted with parents of under-five children who had suffered CAP, community health workers (CHW, and rural medical practitioners (RMP.From September 2013 to January 2014, 30 CS, 43 KIIs, 42 SSIs, and 42 FGDs were conducted. Recognition of danger signs of CAP among caregivers was poor. Fast breathing, an early sign of CAP, was not commonly recognized. Chest in-drawing was recognized as a sign of serious illness, but not commonly monitored by removing a child's clothing. Most cases of mild to moderate CAP were brought to RMP, and more severe cases taken to private clinics in towns. Mothers consulted local RMP directly, but decisions to visit doctors outside the village required consultation with husband or mother-in-law. By the time most cases reached a public tertiary-care hospital, children had been ill for a week and treated by 2-3 providers. Quality of care at government facilities was deemed poor by caregivers.To reduce CAP-associated mortality, recognition of its danger signs and the consequences of treatment delay needed to be better recognized by caregivers, and confidence in government facilities increased. The involvement of RMP in community based CAP programs needs to be investigated further given their widespread

  16. Rooting depth varies differentially in trees and grasses as a function of mean annual rainfall in an African savanna.

    Science.gov (United States)

    Holdo, Ricardo M; Nippert, Jesse B; Mack, Michelle C

    2018-01-01

    A significant fraction of the terrestrial biosphere comprises biomes containing tree-grass mixtures. Forecasting vegetation dynamics in these environments requires a thorough understanding of how trees and grasses use and compete for key belowground resources. There is disagreement about the extent to which tree-grass vertical root separation occurs in these ecosystems, how this overlap varies across large-scale environmental gradients, and what these rooting differences imply for water resource availability and tree-grass competition and coexistence. To assess the extent of tree-grass rooting overlap and how tree and grass rooting patterns vary across resource gradients, we examined landscape-level patterns of tree and grass functional rooting depth along a mean annual precipitation (MAP) gradient extending from ~ 450 to ~ 750 mm year -1 in Kruger National Park, South Africa. We used stable isotopes from soil and stem water to make inferences about relative differences in rooting depth between these two functional groups. We found clear differences in rooting depth between grasses and trees across the MAP gradient, with grasses generally exhibiting shallower rooting profiles than trees. We also found that trees tended to become more shallow-rooted as a function of MAP, to the point that trees and grasses largely overlapped in terms of rooting depth at the wettest sites. Our results reconcile previously conflicting evidence for rooting overlap in this system, and have important implications for understanding tree-grass dynamics under altered precipitation scenarios.

  17. Assessment of grass root effects on soil piping in sandy soils using the pinhole test

    Science.gov (United States)

    Bernatek-Jakiel, Anita; Vannoppen, Wouter; Poesen, Jean

    2017-10-01

    Soil piping is an important land degradation process that occurs in a wide range of environments. Despite an increasing number of studies on this type of subsurface erosion, the impact of vegetation on piping erosion is still unclear. It can be hypothesized that vegetation, and in particular plant roots, may reduce piping susceptibility of soils because roots of vegetation also control concentrated flow erosion rates or shallow mass movements. Therefore, this paper aims to assess the impact of grass roots on piping erosion susceptibility of a sandy soil. The pinhole test was used as it provides quantitative data on pipeflow discharge, sediment concentration and sediment discharge. Tests were conducted at different hydraulic heads (i.e., 50 mm, 180 mm, 380 mm and 1020 mm). Results showed that the hydraulic head was positively correlated with pipeflow discharge, sediment concentration and sediment discharge, while the presence of grass roots (expressed as root density) was negatively correlated with these pipeflow characteristics. Smaller sediment concentrations and sediment discharges were observed in root-permeated samples compared to root-free samples. When root density exceeds 0.5 kg m- 3, piping erosion rates decreased by 50% compared to root-free soil samples. Moreover, if grass roots are present, the positive correlation between hydraulic head and both sediment discharge and sediment concentration is less pronounced, demonstrating that grass roots become more effective in reducing piping erosion rates at larger hydraulic heads. Overall, this study demonstrates that grass roots are quite efficient in reducing piping erosion rates in sandy soils, even at high hydraulic head (> 1 m). As such, grass roots may therefore be used to efficiently control piping erosion rates in topsoils.

  18. Invasive plants and their escape from root herbivory: a worldwide comparison of the root-feeding nematode communities of the dune grass Ammophila arenaria in natural and introduced ranges

    NARCIS (Netherlands)

    Putten, van der W.H.; Yeates, G.W.; Duyts, H.; Schreck Reis, C.; Karssen, G.

    2005-01-01

    Invasive plants generally have fewer aboveground pathogens and viruses in their introduced range than in their natural range, and they also have fewer pathogens than do similar plant species native to the introduced range. However, although plant abundance is strongly controlled by root herbivores

  19. Native Grass Community Management Plan for the Oak Ridge Reservation

    Energy Technology Data Exchange (ETDEWEB)

    Ryon, Michael G [ORNL; Parr, Patricia Dreyer [ORNL; Cohen, Kari [ORNL

    2007-06-01

    Land managers at the Department of Energy's Oak Ridge National Laboratory in East Tennessee are restoring native warm-season grasses and wildflowers to various sites across the Oak Ridge Reservation (ORR). Some of the numerous benefits to planting native grasses and forbs include improved habitat quality for wildlife, improved aesthetic values, lower long-term maintenance costs, and compliance with Executive Order 13112 (Clinton 1999). Challenges to restoring native plants on the ORR include the need to gain experience in establishing and maintaining these communities and the potentially greater up-front costs of getting native grasses established. The goals of the native grass program are generally outlined on a fiscal-year basis. An overview of some of the issues associated with the successful and cost-effective establishment and maintenance of native grass and wildflower stands on the ORR is presented in this report.

  20. Long-term decomposition of grass roots as affected by elevated atmospheric carbon dioxide

    NARCIS (Netherlands)

    Ginkel, van J.H.; Gorissen, A.; Veen, van J.A.

    1996-01-01

    Carbon input into the soil and decomposition processes under elevated CO2 are highly relevant for C sequestering in the soil. Plant growth and decomposition of root material under ambient and elevated atmospheric CO2 concentrations were monitored in wind tunnels. Grass roots (Lolium perenne L.) were

  1. Development Policy in Thailand: From Top-down to Grass Roots.

    Science.gov (United States)

    Kelly, Matthew; Yutthaphonphinit, Phattaraphon; Seubsman, Sam-Ang; Sleigh, Adrian

    2012-11-01

    Top-down industrial development strategies initially dominated the developing world after the second World War but were eventually found to produce inequitable economic growth. For a decade or more, governments and international development agencies have embraced the idea of participatory grass roots development as a potential solution. Here we review Thailand's experience with development strategies and we examine the current focus on participatory approaches. Thai government planning agencies have adopted "people centred development" and a "sufficiency economy", particularly emphasised since the disruptions caused by the 1997 Asian financial crisis. They aim to address the inequitable sharing of the benefits of decades of rapid growth that was particularly unfair for the rural poor. Thai policies aim to decentralise power to the local level, allowing civil society and Non-Governmental Organisations (NGOs) more of a voice in national decision making and promoting sustainable farming practices aimed at enriching rural communities. An example of this change in Thai government policy is the Community Worker Accreditation Scheme which is aiming to develop human resources at the local level by training community based leaders and supporting networks of community organisations. This enables autonomous local development projects led by trained and accredited individuals and groups. The political tensions notable in Thailand at present are part of this modern transition driven by conflicting models of top-down (industrial) development and the bottom-up (participatory) development ideals described above. Once resolved, Thailand will have few obstacles to moving to a new economic level.

  2. Role of grass-legume communities in revegetation of a subalpine mine site in British Columbia

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, K

    1982-01-01

    This study describes an investigation of the potential for pioneer grass-legume communities to stabilize and ameliorate geologically-fresh soil leading to the establishment of a self-sustaining, progressive plant succession on a surface-mined subalpine site. The study area is located 2000 m above sea level in the Canadian Rocky Mountains. Field studies revealed chronological trends in grass-legume communities at four sites revegetated during 1974-1978 including: species composition, legumes (Trifolium repens L., T. hybridum L. and Medicago sativa L.) performing increasingly poorly on the older sites; biomass changes, a shoot to root ratio (S/R) decreasing from 2.3 to 0.2 as the communities aged; and litter accumulation which continued even on the oldest site. Fertilizer (13-16-10) operationally applied at 150-391 kg/ha enhanced the growth of Dactylis gomerata L. and litter degradation, and acidified the soil. Nitrogen fertilization was also associated with two clear inverse relationships identified between D. glomerata and Festuca rubra L. biomass, and between soil pH and phosphorus levels. In greenhouse tests grasses were revealed to be more efficient soil nitrogen consumers than were legumes and nitrogen fixation decreased significantly (P < 0.01) and linearly with increasing grass seeding rates.

  3. Earthworm activity and decomposition of 14C-labelled grass root systems

    NARCIS (Netherlands)

    Uyl, A.; Didden, W.A.M.; Marinussen, J.

    2002-01-01

    Decomposition of 14C-labelled root systems of the grass species Holcus lanatus and Festuca ovina, representative of mesotrophic and oligotrophic situations, respectively, was monitored during 14 months under field conditions in the presence or absence of earthworms (Lumbricus rubellus). During the

  4. Exogenous hydrogen peroxide reversibly inhibits root gravitropism and induces horizontal curvature of primary root during grass pea germination.

    Science.gov (United States)

    Jiang, Jinglong; Su, Miao; Wang, Liyan; Jiao, Chengjin; Sun, Zhengxi; Cheng, Wei; Li, Fengmin; Wang, Chongying

    2012-04-01

    During germination in distilled water (dH(2)O) on a horizontally positioned Petri dish, emerging primary roots of grass pea (Lathyrus sativus L.) grew perpendicular to the bottom of the Petri dish, due to gravitropism. However, when germinated in exogenous hydrogen peroxide (H(2)O(2)), the primary roots grew parallel to the bottom of the Petri dish and asymmetrically, forming a horizontal curvature. Time-course experiments showed that the effect was strongest when H(2)O(2) was applied prior to the emergence of the primary root. H(2)O(2) failed to induce root curvature when applied post-germination. Dosage studies revealed that the frequency of primary root curvature was significantly enhanced with increased H(2)O(2) concentrations. This curvature could be directly counteracted by dimethylthiourea (DMTU), a scavenger of H(2)O(2), but not by diphenylene iodonium (DPI) and pyridine, inhibitors of H(2)O(2) production. Exogenous H(2)O(2) treatment caused both an increase in the activities of H(2)O(2)-scavenging enzymes [including ascorbate peroxidase (APX: EC 1.11.1.11), catalase (CAT: EC 1.11.1.6) and peroxidase (POD: EC 1.11.1.7)] and a reduction in endogenous H(2)O(2) levels and root vitality. Although grass pea seeds absorbed exogenous H(2)O(2) during seed germination, DAB staining of paraffin sections revealed that exogenous H(2)O(2) only entered the root epidermis and not inner tissues. These data indicated that exogenously applied H(2)O(2) could lead to a reversible loss of the root gravitropic response and a horizontal curvature in primary roots during radicle emergence of the seedling. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  5. Forage tree legumes. II. Investigation of nitrogen transfer to an associated grass using a split-root technique

    International Nuclear Information System (INIS)

    Catchpoole, D.W.; Blair, G.J.

    1990-01-01

    The glasshouse study reported, employed a split-root technique, whereby trees of leucaena and gliricidia were grown in boxes with 15 N fed to one half of the root system and the transfer of N to the other half of the box was measured by sampling tree and planted grass. Detection of 15 N in the grass tops and roots from the unlabelled half of the box was used to indicate N transfer from the tree roots to the grass. Transfer of labelled N to the grass amounted to 4.1% in the first 6 week period when 15 N was being injected in the tree root zone. A harvest of the tree and grass was made at 6 weeks and both allowed to regrow for a further 6 weeks with no further addition of 15 N. Over the entire 12 week experimental period 7.6% of the labelled N from the tree was transferred to the grass. The low proportion of N transferred from tree legume to the grass in this experiment, where herbage was cut and removed, is similar to the findings in the earlier field experiment and indicates that, in such a system, little direct beneficial effect of N fixation would be expected in an understorey grass or food crop. 24 refs., 4 tabs

  6. Interspecific associations and community structure: A local survey and analysis in a grass community

    Directory of Open Access Journals (Sweden)

    WenJun Zhang

    2014-09-01

    Full Text Available Interspecific associations in the plant community may help to understand the self-organizing assembly and succession of the community. In present study, Pearson correlation, net correlation, Spearman rank correlation, and point correlation were used to detect the interspecific (inter-family associations of grass species (families using the sampling data collected in a grass community of Zhuhai, China. We found that most associations between grass species (families were positive associations. The competition/interference/niche separation between grass species (families was not significant. A lot of pairs of grass species and families with statistically significant interspecific (inter-family associations based on four correlation measures were discovered. Cluster trees for grass species/families were obtained by using cluster analysis. Relationship among positive/negative associations, interspecific relationship and community succession/stability/robustness was discussed. I held that species with significant positive or negative associations are generally keystone species in the community. Although both negative and positive associations occur in the community succession, the adaptation and selection will finally result in the successful coexistence of the species with significant positive associations in the climax community. As the advance of community succession, the significant positive associations increase and maximize in climax community, and the significant negative associations increase to a maximum and then decline into climax community. Dominance of significant positive associations in the climax community means the relative stablility and equilibrium of the community. No significant associations usually account for the majority of possible interspecific associations at each phase of community succession. They guarantee the robustness of community. They are candidates of keystone species. Lose of some existing keystone species might be

  7. Improvement of workíng environment - from a grass-root strategy to institutionalized professionalism

    DEFF Research Database (Denmark)

    Jacobsen, Thomas

    2002-01-01

    Improvement of working environment as a tool to promote sustainable development - from a grass-root strategy to institutionalized professionalism. It is now more than 25 years since substitution of organic solvents started to be considered as a meaningful way in Denmark to reduce harmful effects...... on workers. During that period different groups of actors have been involved, new institutions to improve working environment have emerged, and legislation has been changed. The paper will describe the development from a grass-root strategy to improve working environment to a much more complex situation...... where working environment professionals play an important role, and where the concept of ‘cleaner technology’ is generally accepted as a tool to promote sustainable development in the Danish society. The paper will also discuss the necessity of incorporation of working environment considerations...

  8. Environmental justice: Grass roots reach the White House lawn

    Energy Technology Data Exchange (ETDEWEB)

    Kratch, K.

    1995-05-01

    When 500 demonstrators gathered in 1982 to protest the siting of a polychlorinated-biphenyl landfill in predominantly black Warren County, N.C., cries of environmental racism filled the air. In response, District of Columbia Congressional Delegate Walter Fauntroy requested that the General Accounting Office investigate a possible link between hazardous waste landfill siting and the racial and socio-economic mix of surrounding communities. The environmental justice movement, as it is known today, had been born. Environmental justice is conceived as the right of all people--regardless of race, ethnicity, culture or income--to live in a healthy environment, breathe clean air, drink clean water and eat uncontaminated foods. The concept assumes that everyone is entitled to fair environmental protection without any population segment bearing a disproportionate pollution burden.

  9. Grass Roots Design for the Ocean Science of Tomorrow

    Science.gov (United States)

    Jul, S.; Peach, C. L.; Kilb, D. L.; Schofield, O.; Fisher, C.; Quintana, C.; Keen, C. S.

    2010-12-01

    Current technologies offer the opportunity for ocean science to expand its traditional expeditionary base by embracing e-science methods of continuous interactive real-time research. The Ocean Observatories Initiative Cyberinfrastructure (OOI CI) is an NSF-funded effort to develop a national cyberinfrastructure that will allow researchers, educators and others to share in this new type of oceanography. The OOI is an environmental observatory spanning coastal waters to the deep ocean, enabled by the CI to offer scientists continuous interactive access to instruments in the ocean, and allow them to search, subscribe to and access real-time or archival data streams. It will also supply interactive analysis and visualization tools, and a virtual social environment for discovering and realizing collaborative opportunities. Most importantly, it provides an extensible open-access cyberinfrastructure that supports integration of new technologies and observatories, and which will allow adoption of its tools elsewhere, such as by the Integrated Ocean Observing System (IOOS). The eventual success of such a large and flexible system requires the input of a large number of people, and user-centered design has been a driving philosophy of the OOI CI from its beginning. Support for users’ real needs cannot be designed as an add-on or casual afterthought, but must be deeply embedded in all aspects of a project, from inception through architecture, implementation, and deployment. The OOI CI strategy is to employ the skills and knowledge of a small number of user experience professionals to channel and guide a very large collective effort to deliver tools, interfaces and interactions that are intellectually stimulating, scientifically productive, and conducive to innovation. Participation from all parts of the user community early in the design process is vital to meeting these goals. The OOI user experience team will be on hand to meet members of the Earth and ocean sciences

  10. Toxic effects of Cu2+ on growth, nutrition, root morphology, and distribution of Cu in roots of Sabi grass

    International Nuclear Information System (INIS)

    Kopittke, P.M.; Asher, C.J.; Blamey, F.P.C.; Menzies, N.W.

    2009-01-01

    Sabi grass (Urochloa mosambicensis (Hack.) Dandy) (a C4 species of Poaceae) is commonly used to revegetate disturbed sites in low-rainfall environments, but comparatively little is known regarding copper (Cu) toxicity in this species. A dilute nutrient solution culture experiment was conducted for 10 d to examine the effects of elevated Cu 2+ activities ({Cu 2+ }) on the growth of Sabi grass. Growth was inhibited by high Cu in solution, with a 50% reduction in the relative fresh mass occurring at 1.0 μM {Cu 2+ } for the roots and 1.2 μM {Cu 2+ } for the shoots. In solutions containing 1.2-1.9 μM {Cu 2+ }, many of the roots ruptured due to the tearing and separation of the rhizodermis and outer cortex from the underlying tissues. Transmission electron microscopy revealed that Cu-rich deposits were found to accumulate predominantly within vacuoles. Due to limited translocation of Cu from the roots to the shoots, phytotoxicity is likely to be more of a problem in remediation of Cu-toxic sites than is Cu toxicity of fauna consuming the above-ground biomass.

  11. JICA -- working from the grass roots up. Vietnam.

    Science.gov (United States)

    1997-11-01

    The fact that Japan has reduced its foreign aid by 10% for fiscal 1998 will require the Japan International Cooperation Agency's (JICA) Medical Cooperation Department (MCD) to review both the number of projects it funds and program management. The MCD is developing new guidelines for primary health care programs that will reflect the principles embedded in the Program of Action of the 1994 International Conference on Population and Development. The managing director of the MCD believes that an effective way to promote primary health care is to focus on reproductive health/family planning and then broaden the scope of activities. The current reproductive health project being implemented in Nghe An Province of Viet Nam is expected to make a great contribution to the improvement of community health. The MCD also wants to explore bottom-up primary health care approaches with the cooperation of nongovernmental organizations (NGOs). Thus, the Viet Nam project is being conducted in collaboration with the NGO JOICFP and may pioneer new avenues in governmental/NGO cooperation worldwide. The new budget cuts will force JICA to review its disbursement and project management procedures. Thus, all future projects will use the project cycle management approach, including the use of a participatory project design matrix. JICA will also be fostering a sense of ownership of projects from the grassroots to the national level that will allow projects to become sustainable.

  12. Tele-periodontics - Oral health care at a grass root level.

    Science.gov (United States)

    Avula, Haritha

    2015-01-01

    A new concept of tele-periodontics, which merges the innovative technology of telecommunications and the field of periodontics, is proposed. This new field of tele-periodontics will have an infinite potential where access to a specialist will be provided at a grass root level, enhancing effective delivery of therapy and information to the rural and under privileged areas. It would allow the specialist and the patient to interact either by video conferencing (real time) or through supportive information (store and forward) over geographic distances. Different probabilities of tele-periodontics such as tele consultation, tele training, tele education and tele support are also discussed in this paper.

  13. Physiological Ecology of Clostridium glycolicum RD-1, an Aerotolerant Acetogen Isolated from Sea Grass Roots

    OpenAIRE

    Küsel, Kirsten; Karnholz, Arno; Trinkwalter, Tanja; Devereux, Richard; Acker, Georg; Drake, Harold L.

    2001-01-01

    An anaerobic, H2-utilizing bacterium, strain RD-1, was isolated from the highest growth-positive dilution series of a root homogenate prepared from the sea grass Halodule wrightii. Cells of RD-1 were gram-positive, spore-forming, motile rods that were linked by connecting filaments. Acetate was produced in stoichiometries indicative of an acetyl coenzyme A (acetyl-CoA) pathway-dependent metabolism when RD-1 utilized H2-CO2, formate, lactate, or pyruvate. Growth on sugars or ethylene glycol yi...

  14. Associative diazotrophic bacteria in grass roots and soils from heavy metal contaminated sites.

    Science.gov (United States)

    Moreira, Fátima M S; Lange, Anderson; Klauberg-Filho, Osmar; Siqueira, José O; Nóbrega, Rafaela S A; Lima, Adriana S

    2008-12-01

    This work aimed to evaluate density of associative diazotrophic bacteria populations in soil and grass root samples from heavy metal contaminated sites, and to characterize isolates from these populations, both, phenotypically (Zinc, Cadmium and NaCl tolerance in vitro, and protein profiles) and genotypically (16S rDNA sequencing), as compared to type strains of known diazotrophic species. Densities were evaluated by using NFb, Fam and JNFb media, commonly used for enrichment cultures of diazotrophic bacteria. Bacterial densities found in soil and grass root samples from contaminated sites were similar to those reported for agricultural soils. Azospirillum spp. isolates from contaminated sites and type strains from non-contaminated sites varied substantially in their in vitro tolerance to Zn+2 and Cd+2, being Cd+2 more toxic than Zn+2. Among the most tolerant isolates (UFLA 1S, 1R, S181, S34 and S22), some (1R, S34 and S22) were more tolerant to heavy metals than rhizobia from tropical and temperate soils. The majority of the isolates tolerant to heavy metals were also tolerant to salt stress as indicated by their ability to grow in solid medium supplemented with 30 g L(-1) NaCl. Five isolates exhibited high dissimilarity in protein profiles, and the 16S rDNA sequence analysis of two of them revealed new sequences for Azospirillum.

  15. Theory and Practice of Sustainable Development: Path to Managing Rural Grass-roots Party Organization from the Perspective of Impetus

    Science.gov (United States)

    Zhong, Xianzhe

    2018-02-01

    Impetus is the most fundamental guarantee for the survival and progress of organization. The rural grass-roots party organization should serve as a battle fortress of party helping realize the purpose of party in the village. Therefore, to strengthen the management of rural party branches, it is imperative to optimize their impetus, stepping on the basic paths: developing and utilizing material force, and digging and stimulating spiritual force for rural grass-roots party organization construction; adhering to the dialectical view on impetus to highlight both material and spiritual motivations.

  16. Waste management and pollution at grass-root level in Malaysia: the vision 2020 perspective

    International Nuclear Information System (INIS)

    Abdul Fatah Yussif; Abdul Rashid Mohamed Shariff

    2001-01-01

    Malaysia can gain enormously by embracing the global environmental awareness campaign by he United nations Environmental Protection Agency. In order to reap these benefits, a substantial amount of the national budget has to be allocated to oversee waste management and pollution control. However, if certain constrains are not properly addressed, it will lead to waste management and pollution control problem at both urban and municipal levels. The major constrains as identified in a study entitled The implementation constrains in waste management in Malaysia (Law Hieng Ding, 1992), include, lack of proper education of the masses, negligence and discriminate acts, lack of law enforcement by the relevant local authorities and probably discrepancy in the degree of coordination and planning among government agencies. This presentation will address these constraints and suggest a mechanism to better enhance efficient control and management of waste and pollution at grass root level. (Author)

  17. 26 CFR 1.501(h)-3 - Lobbying or grass roots expenditures normally in excess of ceiling amount.

    Science.gov (United States)

    2010-04-01

    ... excess of ceiling amount. 1.501(h)-3 Section 1.501(h)-3 Internal Revenue INTERNAL REVENUE SERVICE... § 1.501(h)-3 Lobbying or grass roots expenditures normally in excess of ceiling amount. (a) Scope. This section provides rules under section 501(h) for determining whether an organization that has...

  18. E-learning for grass-roots emergency public health personnel: Preliminary lessons from a national program in China.

    Science.gov (United States)

    Xu, Wangquan; Jiang, Qicheng; Qin, Xia; Fang, Guixia; Hu, Zhi

    2016-07-19

    In China, grass-roots emergency public health personnel have relatively limited emergency response capabilities and they are constantly required to update their professional knowledge and skills due to recurring and new public health emergencies. However, professional training, a principal solution to this problem, is inadequate because of limitations in manpower and financial resources at grass-roots public health agencies. In order to provide a cost-effective and easily expandable way for grass-roots personnel to acquire knowledge and skills, the National Health Planning Commission of China developed an emergency response information platform and provided trial access to this platform in Anhui and Heilongjiang provinces in China. E-learning was one of the modules of the platform and this paper has focused on an e-learning pilot program. Results indicated that e-learning had satisfactorily improved the knowledge and ability of grass-roots emergency public health personnel, and the program provided an opportunity to gain experience in e-course design and implementing e-learning. Issues such as the lack of personalized e-courses and the difficulty of evaluating the effectiveness of e-learning are topics for further study.

  19. Making it in a 'saturated' market. How the Spence Center wins women's hearts with grass-roots marketing.

    Science.gov (United States)

    Moore, P L

    1997-01-01

    The Spence Centers, full-service, independent clinics for women, depend on grass-roots outreach to cultivate customers and build brand equity. The Centers have garnered national and international press coverage and made enough friends to open a fourth operation.

  20. Community structure affects annual grass weed invasion during restoration of a shrub-steppe ecosystem

    Science.gov (United States)

    Phil S. Allen; Susan E. Meyer

    2014-01-01

    Ecological restoration of shrub-steppe communities in the western United States is often hampered by invasion of exotic annual grasses during the process. An important question is how to create restored communities that can better resist reinvasion by these weeds. One hypothesis is that communities comprised of species that are functionally similar to the invader will...

  1. Quantification of root associated nitrogen fixation in kallar grass as estimated by sup/15/nitrogen isotope dilution

    International Nuclear Information System (INIS)

    Malik, K.A.; Zafar, Y.

    1985-01-01

    Present investigations were made by using sup/15/N isotope dilution technique to quantitatively estimate BNF in Kallar grass when grown under controlled conditions in nutrient solution and inoculated with N sub/2/-fixing bacteria. Azospirillum brasilense and two isolates from the rhizosphere of kallar grass were used as inoculant. After harvest acetylen reduction of roots, total yield, total N and sup/15/ N analysis were made. Total-N in inoculated treatments was 2-3 times higher than in control and so were the fresh and dry weight yields. The estimates based on isotopic dilution indicated that 50-70 percent N in the plant was derived from BNF in case of inoculated treatment. The results based on N balance gave relatively lower values of 40-60 percent of total N derived from fixation. The data revealed that in Kallar grass a substantial amount of plant N is derived from BNF. (orig./A.B.)

  2. Genotypic Diversity for Biomass Accumulation and Shoot-Root Allometry in the Grass Brachypodium distachyon

    Science.gov (United States)

    Jansson, C.; Handakumbura, P. P.; Fortin, D.; Stanfill, B.; Rivas-Ubach, A.

    2017-12-01

    Predicting carbon uptake, assimilation and allocation for current and future biogeographical environments, including climate, is critical for our ability to select and/or design plant genotypes to meet increasing demand for plant biomass going into food, feed and energy production, while at the same time maintain or increase soil organic matter (SOM for soil fertility and carbon storage, and reduce emission of greenhouse gasses. As has been demonstrated for several plant species allometric relationships may differ between plant genotypes. Exploring plant genotypic diversity for biomass accumulation and allometry will potentially enable selection of genotypes with high CO2 assimilation and favorable allocation of recent photosynthate into above-ground and below-ground biomass. We are investigating genotypic diversity for PFTs in natural accessions of the annual C3 grass Brachypodium distachyon under current and future climate scenarios and how genotypic diversity correlates with metabolite profiles in aboveground and below-ground biomass. In the current study, we compare effects from non-stressed and drought conditions on biomass accumulation and shoot-root allometry.

  3. The grass-roots conservative against gender equality : The case study of antifeminism local movement in Japan

    OpenAIRE

    Suzuki, Ayaka

    2017-01-01

    Conservative movements are intensifying advertisement in fierce conflict with progressive social movements in the contemporary Japanese society. In particular, the Japanese Society for History Textbook Reform has taken action in terms of revisionism since late 1990s. Conservative groups have held protest movements against gender equality since early 2000, which resulted in drastic impact on the government. These conservative movements have received attention as new grass-roots conservative mo...

  4. Mangrove root communities in Jobos Bay

    International Nuclear Information System (INIS)

    Yoshioka, P.M.

    1975-01-01

    Based on the presence and absence of species, at least two major types of mangrove root communities exist in Jobos Bay. One community, occurring mainly along the Aguirre Ship Channel, is composed of species characteristic of coastal waters. Another occurring in Jobos Bay and in mangrove channels in the vinicity of Mar Negro Lagoon is characterized by embayment species. Water mass is the best single parameter which correlates with the different communities. In general, subtidal species are more susceptible to elevated temperatures than intertidal species and consequently will be the first affected. Because most of the predators and competitors are subtidal, the predation and competition which limit populations may be cut back. The effect will first be seen in increased populations of barnacles, because they are severely limited by predation and competition but are physiologically quite tolerant. The intertidal species should flourish (on a relative basis) and their vertical distributions should be extended downward. These effects are only primary. Many species which would do best in thermally altered situations are colonizing or fugitive species. It is unknown whether such an assemblage could persist with continued recruitment and growth of new individuals. The dominance of these colonizing or fugitive species may be only temporary, however, because blue-green algae are tolerant of elevated temperatures and have a negative effect on barnacle recruitment and growth. Consequently, blue-green algae may eventually dominate thermally affected mangrove roots

  5. Bacterial endophyte communities of three agricultural important grass species differ in their response towards management regimes

    Science.gov (United States)

    Wemheuer, Franziska; Kaiser, Kristin; Karlovsky, Petr; Daniel, Rolf; Vidal, Stefan; Wemheuer, Bernd

    2017-01-01

    Endophytic bacteria are critical for plant growth and health. However, compositional and functional responses of bacterial endophyte communities towards agricultural practices are still poorly understood. Hence, we analyzed the influence of fertilizer application and mowing frequency on bacterial endophytes in three agriculturally important grass species. For this purpose, we examined bacterial endophytic communities in aerial plant parts of Dactylis glomerata L., Festuca rubra L., and Lolium perenne L. by pyrotag sequencing of bacterial 16S rRNA genes over two consecutive years. Although management regimes influenced endophyte communities, observed responses were grass species-specific. This might be attributed to several bacteria specifically associated with a single grass species. We further predicted functional profiles from obtained 16S rRNA data. These profiles revealed that predicted abundances of genes involved in plant growth promotion or nitrogen metabolism differed between grass species and between management regimes. Moreover, structural and functional community patterns showed no correlation to each other indicating that plant species-specific selection of endophytes is driven by functional rather than phylogenetic traits. The unique combination of 16S rRNA data and functional profiles provided a holistic picture of compositional and functional responses of bacterial endophytes in agricultural relevant grass species towards management practices.

  6. Associative diazotrophic bacteria in grass roots and soils from heavy metal contaminated sites

    Directory of Open Access Journals (Sweden)

    Fátima M.S. Moreira

    2008-12-01

    Full Text Available This work aimed to evaluate density of associative diazotrophic bacteria populations in soil and grass root samples from heavy metal contaminated sites, and to characterize isolates from these populations, both, phenotypically (Zinc, Cadmium and NaCl tolerance in vitro, and protein profiles and genotypically (16S rDNA sequencing, as compared to type strains of known diazotrophic species. Densities were evaluated by using NFb, Fam and JNFb media, commonly used for enrichment cultures of diazotrophic bacteria. Bacterial densities found in soil and grass root samples from contaminated sites were similar to those reported for agricultural soils. Azospirillum spp. isolates from contaminated sites and type strains from non-contaminated sites varied substantially in their in vitro tolerance to Zn+2 and Cd+2, being Cd+2 more toxic than Zn+2. Among the most tolerant isolates (UFLA 1S, 1R, S181, S34 and S22, some (1R, S34 and S22 were more tolerant to heavy metals than rhizobia from tropical and temperate soils. The majority of the isolates tolerant to heavy metals were also tolerant to salt stress as indicated by their ability to grow in solid medium supplemented with 30 g L-1 NaCl. Five isolates exhibited high dissimilarity in protein profiles, and the 16S rDNA sequence analysis of two of them revealed new sequences for Azospirillum.Objetivou-se avaliar a densidade de populações de bactérias diazotróficas associativas em amostras de solos e de raízes de gramíneas oriundas de sítios contaminados com metais pesados, e caracterizar isolados destas populações através da análise fenotípica (tolerância aos metais pesados zinco e cádmio e à NaCl in vitro, perfis protéicos, e genotípica (seqüenciamento de 16S rDNA, comparados às estirpes tipo das mesmas espécies. As densidades foram avaliadas nos meios NFb, Fam e LGI, comumente utilizados para culturas de enriquecimento de populações de bactérias diazotróficas associativas. As densidades

  7. Ecophysiological Responses of Invasive and Native Grass Communities with Simulated Warming

    Science.gov (United States)

    Quade, B.; Ravi, S.; Huxman, T. E.

    2010-12-01

    William Quade1, Sujith Ravi2, Ashley Weide2, Greg Barron-Gafford2, Katerina Dontsova2 and Travis E Huxman2 1Carthage College, WI 2 B2 Earthscience & UA Biosphere 2, University of Arizona, Tucson. Abstract Climate change, anthropogenic disturbances and lack of proper management practices have rendered many arid regions susceptible to invasions by exotic grasses with consequent ecohydrological, biogeochemical and socio economic implications. Thus, understanding the ecophysiological processes driving these large-scale vegetation shifts in drylands, in the context of rising temperatures and recurrent droughts is fundamental to global change research. Using the Biosphere 2 facility to maintain distinct temperature treatments of ambient and predicted warmer conditions (+ 4o C) inside, we compared the physiological (e.g. photosynthesis, stomatal conductance, biomass) responses of a native grass - Heteropogan contortus (Tanglehead) and an invasive grass - Pennisetum ciliare (Buffelgrass) growing in single and mixed communities. The results indicate that Buffelgrass can assimilate more CO2 per unit leaf area under current conditions, though warming seems to inhibit the performance when looking at biomass, photosynthesis and stomatal conductance. Under similar moisture regimes Buffelgrass performed better than Tangle head in mixed communities regardless of the temperature. Both grasses had decrease in stomatal conductance with warmer conditions, however the Buffel grass did not have the same decrease of conductance when planted in a mixed communities. Key words: Buffelgrass, Tanglehead, Biosphere 2, stomatal conductance, climate change

  8. Operational Assessment of ICDS Scheme at Grass Root Level in a Rural Area of Eastern India: Time to Introspect

    Science.gov (United States)

    Sahoo, Jyotiranjan; Mahajan, Preetam B; Bhatia, Vikas; Patra, Abhinash K; Hembram, Dilip Kumar

    2016-01-01

    Introduction Integrated Child Development Service (ICDS), a flagship program of Government of India (GoI) for early childhood development hasn’t delivered the desired results since its inception four decades ago. This could be due to infrastructural problems, lack of awareness and proper utilization by the local people, inadequate program monitoring and corruption in food supplies, etc. This study is an audit of 36 Anganwadi centres at Khordha district, Odisha, to evaluate the implementation of the ICDS. Aim To assess operational aspects of ICDS program in a rural area of Odisha, in Eastern India. Materials and Methods A total of 36 out of 50 Anganwadi Centres (AWCs) were included in the study. We interviewed the Anganwadi Workers (AWW) and carried out observations on the AWCs using a checklist. We gathered information under three domains manpower resource, material resource and functional aspects of the AWC. Results Most of the AWCs were adequately staffed. Most of the AWWs were well educated. However, more than 85% of the AWCs did not have designated building for daily functioning which resulted in issues related to implementation of program. Water, toilet and electricity facilities were almost non-existent. Indoor air pollution posed a serious threat to the health of the children. Lack of play materials; lack of health assessment tools for promoting, monitoring physical and mental development; and multiple de-motivating factors within the work environment, eventually translated into lack of faith among the beneficiaries in the rural community. Conclusion Inadequate infrastructure and logistic supply were the most prominent issues found, which resulted in poor implementation of ICDS program. Strengthening of grass root level facilities based on need assessment, effective monitoring and supervision will definitely help in revamping the ICDS program in rural areas. PMID:28208890

  9. ROOT HAIR DEFECTIVE SIX-LIKE Class I Genes Promote Root Hair Development in the Grass Brachypodium distachyon.

    Directory of Open Access Journals (Sweden)

    Chul Min Kim

    2016-08-01

    Full Text Available Genes encoding ROOT HAIR DEFECTIVE SIX-LIKE (RSL class I basic helix loop helix proteins are expressed in future root hair cells of the Arabidopsis thaliana root meristem where they positively regulate root hair cell development. Here we show that there are three RSL class I protein coding genes in the Brachypodium distachyon genome, BdRSL1, BdRSL2 and BdRSL3, and each is expressed in developing root hair cells after the asymmetric cell division that forms root hair cells and hairless epidermal cells. Expression of BdRSL class I genes is sufficient for root hair cell development: ectopic overexpression of any of the three RSL class I genes induces the development of root hairs in every cell of the root epidermis. Expression of BdRSL class I genes in root hairless Arabidopsis thaliana root hair defective 6 (Atrhd6 Atrsl1 double mutants, devoid of RSL class I function, restores root hair development indicating that the function of these proteins has been conserved. However, neither AtRSL nor BdRSL class I genes is sufficient for root hair development in A. thaliana. These data demonstrate that the spatial pattern of class I RSL activity can account for the pattern of root hair cell differentiation in B. distachyon. However, the spatial pattern of class I RSL activity cannot account for the spatial pattern of root hair cells in A. thaliana. Taken together these data indicate that that the functions of RSL class I proteins have been conserved among most angiosperms-monocots and eudicots-despite the dramatically different patterns of root hair cell development.

  10. Effects of field-grown genetically modified Zoysia grass on bacterial community structure.

    Science.gov (United States)

    Lee, Yong-Eok; Yang, Sang-Hwan; Bae, Tae-Woong; Kang, Hong-Gyu; Lim, Pyung-Ok; Lee, Hyo-Yeon

    2011-04-01

    Herbicide-tolerant Zoysia grass has been previously developed through Agrobacterium-mediated transformation. We investigated the effects of genetically modified (GM) Zoysia grass and the associated herbicide application on bacterial community structure by using culture-independent approaches. To assess the possible horizontal gene transfer (HGT) of transgenic DNA to soil microorganisms, total soil DNAs were amplified by PCR with two primer sets for the bar and hpt genes, which were introduced into the GM Zoysia grass by a callus-type transformation. The transgenic genes were not detected from the total genomic DNAs extracted from 1.5 g of each rhizosphere soils of GM and non-GM Zoysia grasses. The structures and diversities of the bacterial communities in rhizosphere soils of GM and non-GM Zoysia grasses were investigated by constructing 16S rDNA clone libraries. Classifier, provided in the RDP II, assigned 100 clones in the 16S rRNA gene sequences library into 11 bacterial phyla. The most abundant phyla in both clone libraries were Acidobacteria and Proteobacteria. The bacterial diversity of the GM clone library was lower than that of the non- GM library. The former contained four phyla, whereas the latter had seven phyla. Phylogenetic trees were constructed to confirm these results. Phylogenetic analyses of the two clone libraries revealed considerable difference from each other. The significance of difference between clone libraries was examined with LIBSHUFF statistics. LIBSHUFF analysis revealed that the two clone libraries differed significantly (P〈0.025), suggesting alterations in the composition of the microbial community associated with GM Zoysia grass.

  11. Poverty as an Abuse of Human Rights in Ghana. : A grass roots perspective on poverty and human rights.

    OpenAIRE

    Armah, Collins

    2009-01-01

    The study aimed at getting a grass root opinion on poverty and why Ghana is still poor after 50 years of independence in spite of her richness in natural resources, second largest producer of cocoa in the word and appreciable stable political environment. The opinions of the ordinary people in the Bia district and their observed living conditions was analysed in line with theoretical basis of the study and previous studies to justify the stance that poverty should be considered as an abuse of...

  12. All hazardous waste politics is local: Grass-roots advocacy and public participation in siting and cleanup decisions

    Energy Technology Data Exchange (ETDEWEB)

    Lowry, R.C.

    1998-12-31

    The combined effects of federalism and interest group pluralism pose particularly difficult problems for hazardous waste siting and cleanup decisions. Most national environmental groups have only limited involvement in local hazardous waste politics, while local grass-roots advocates have very different interests and sometimes are pitted against one another. Both the Environmental protection Agency and the Department of energy recently have begun to use site-specific citizen advisory boards at cleanup sites. This approach appears to improve communications at some sites, but does not address the issues of ``not in my back yard`` politics and alleged inequitable exposure to hazardous wastes.

  13. Comparison of intestinal bacterial communities in grass carp, Ctenopharyngodon idellus, from two different habitats

    Science.gov (United States)

    Ni, Jiajia; Yu, Yuhe; Zhang, Tanglin; Gao, Lei

    2012-09-01

    The intestinal bacteria of vertebrates form a close relationship with their host. External and internal conditions of the host, including its habitat, affect the intestinal bacterial community. Similarly, the intestinal bacterial community can, in turn, influence the host, particularly with respect to disease resistance. We compared the intestinal bacterial communities of grass carp that were collected from farm-ponds or a lake. We conducted denaturing gradient gel electrophoresis of amplified 16S rRNA genes, from which 66 different operational taxonomic units were identified. Using both the unweighted pair-group method with arithmetic means clustering and principal component analysis ordination, we found that the intestinal bacterial communities from the two groups of pond fish were clustered together and inset into the clusters of wild fish, except for DF-7, and there was no significant correlation between genetic diversity of grass carp and their intestinal bacterial communities (Mantel one-tailed test, R=0.157, P=0.175). Cetobacterium appeared more frequently in the intestine of grass carp collected from pond. A more thorough understanding of the role played by intestinal microbiota on fish health would be of considerable benefit to the aquaculture industry.

  14. Some observation on the root growth of young apple trees and their uptake of nutrients when grown in herbicided strips in grassed orchards

    International Nuclear Information System (INIS)

    Atkinson, D.

    1977-01-01

    Root laboratory observations of the root growth of 4-year-old trees of Cox/M.26 planted in a herbicided strip in grass indicated that during the year 70% of the new growth occurred in the strip. Growth appeared to begin earlier during the year under bare soil than under grass. Nitrogen absorption from the strip and the grassed alley was assessed by measuring 15 N uptake; at 10 cm depth uptake was almost entirely from the strip. An experiment using 2-year-old trees of Cox/M.106 and 15 N placements at 7.5 and 15 cm depths in the strip and 15 cm in the grassed alley gave similar results. With 32 P as a tracer and similar trees a small amount of uptake from 25 cm depth under grass was detected. The experiments indicate that young trees produce most of their new roots in the herbicide strips where most of their nutrient uptake occurs and little or none from the grassed alleys. The absorption of nitrogen into the leaves was greater in early summer than autumn

  15. Population dynamics of host-specific root-feeding cyst nematode and resource quantity in the root zone of a clonal grass

    NARCIS (Netherlands)

    Stoel, C.D.; Duyts, H.; Putten, van der W.H.

    2006-01-01

    Recent studies have suggested that root-feeding nematodes influence plant community dynamics, but few studies have investigated the population dynamics of the nematodes. In coastal foredunes, feeding-specialist cyst nematodes (Heterodera spp.) are dominant in the soil nematode community and

  16. Population dynamics of a host-specific root-feeding cyst nematode and resource quantity in the root zone of a clonal grass

    NARCIS (Netherlands)

    Van der Stoel, C.D.; Duyts, H.; Van der Putten, W.H.

    2006-01-01

    Recent studies have suggested that root-feeding nematodes influence plant community dynamics, but few studies have investigated the population dynamics of the nematodes. In coastal foredunes, feeding-specialist cyst nematodes (Heterodera spp.) are dominant in the soil nematode community and

  17. Parasiticidal effects of Morus alba root bark extracts against Ichthyophthirius multifiliis infecting grass carp

    Science.gov (United States)

    Ichthyophthirius multifiliis (Ich) is an important fish parasite that can result in significant losses in aquaculture. In order to find efficacious drugs to control Ich, the root bark of Morus alba, a traditional Chinese medicine, was evaluated for its antiprotozoal activity. The M. alba root bark w...

  18. Simulating the partitioning of biomass and nitrogen between roots and shoot in crop and grass plants

    NARCIS (Netherlands)

    Yin, X.; Schapendonk, A.H.C.M.

    2004-01-01

    Quantification of the assimilate partitioning between roots and shoot has been one of the components that need improvement in crop growth models. In this study we derived two equations for root-shoot partitioning of biomass and nitrogen (N) that hold for crops grown under steady-state conditions.

  19. Plant Invasions Associated with Change in Root-Zone Microbial Community Structure and Diversity.

    Directory of Open Access Journals (Sweden)

    Richard R Rodrigues

    Full Text Available The importance of plant-microbe associations for the invasion of plant species have not been often tested under field conditions. The research sought to determine patterns of change in microbial communities associated with the establishment of invasive plants with different taxonomic and phenetic traits. Three independent locations in Virginia, USA were selected. One site was invaded by a grass (Microstegium vimineum, another by a shrub (Rhamnus davurica, and the third by a tree (Ailanthus altissima. The native vegetation from these sites was used as reference. 16S rRNA and ITS regions were sequenced to study root-zone bacterial and fungal communities, respectively, in invaded and non-invaded samples and analyzed using Quantitative Insights Into Microbial Ecology (QIIME. Though root-zone microbial community structure initially differed across locations, plant invasion shifted communities in similar ways. Indicator species analysis revealed that Operational Taxonomic Units (OTUs closely related to Proteobacteria, Acidobacteria, Actinobacteria, and Ascomycota increased in abundance due to plant invasions. The Hyphomonadaceae family in the Rhodobacterales order and ammonia-oxidizing Nitrospirae phylum showed greater relative abundance in the invaded root-zone soils. Hyphomicrobiaceae, another bacterial family within the phyla Proteobacteria increased as a result of plant invasion, but the effect associated most strongly with root-zones of M. vimineum and R. davurica. Functional analysis using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt showed bacteria responsible for nitrogen cycling in soil increased in relative abundance in association with plant invasion. In agreement with phylogenetic and functional analyses, greater turnover of ammonium and nitrate was associated with plant invasion. Overall, bacterial and fungal communities changed congruently across plant invaders, and support the hypothesis that

  20. Linking Microbial Community Structure and Function During the Acidified Anaerobic Digestion of Grass

    Directory of Open Access Journals (Sweden)

    Aoife Joyce

    2018-03-01

    Full Text Available Harvesting valuable bioproducts from various renewable feedstocks is necessary for the critical development of a sustainable bioeconomy. Anaerobic digestion is a well-established technology for the conversion of wastewater and solid feedstocks to energy with the additional potential for production of process intermediates of high market values (e.g., carboxylates. In recent years, first-generation biofuels typically derived from food crops have been widely utilized as a renewable source of energy. The environmental and socioeconomic limitations of such strategy, however, have led to the development of second-generation biofuels utilizing, amongst other feedstocks, lignocellulosic biomass. In this context, the anaerobic digestion of perennial grass holds great promise for the conversion of sustainable renewable feedstock to energy and other process intermediates. The advancement of this technology however, and its implementation for industrial applications, relies on a greater understanding of the microbiome underpinning the process. To this end, microbial communities recovered from replicated anaerobic bioreactors digesting grass were analyzed. The bioreactors leachates were not buffered and acidic pH (between 5.5 and 6.3 prevailed at the time of sampling as a result of microbial activities. Community composition and transcriptionally active taxa were examined using 16S rRNA sequencing and microbial functions were investigated using metaproteomics. Bioreactor fraction, i.e., grass or leachate, was found to be the main discriminator of community analysis across the three molecular level of investigation (DNA, RNA, and proteins. Six taxa, namely Bacteroidia, Betaproteobacteria, Clostridia, Gammaproteobacteria, Methanomicrobia, and Negativicutes accounted for the large majority of the three datasets. The initial stages of grass hydrolysis were carried out by Bacteroidia, Gammaproteobacteria, and Negativicutes in the grass biofilms, in addition to

  1. Linking Microbial Community Structure and Function During the Acidified Anaerobic Digestion of Grass.

    Science.gov (United States)

    Joyce, Aoife; Ijaz, Umer Z; Nzeteu, Corine; Vaughan, Aoife; Shirran, Sally L; Botting, Catherine H; Quince, Christopher; O'Flaherty, Vincent; Abram, Florence

    2018-01-01

    Harvesting valuable bioproducts from various renewable feedstocks is necessary for the critical development of a sustainable bioeconomy. Anaerobic digestion is a well-established technology for the conversion of wastewater and solid feedstocks to energy with the additional potential for production of process intermediates of high market values (e.g., carboxylates). In recent years, first-generation biofuels typically derived from food crops have been widely utilized as a renewable source of energy. The environmental and socioeconomic limitations of such strategy, however, have led to the development of second-generation biofuels utilizing, amongst other feedstocks, lignocellulosic biomass. In this context, the anaerobic digestion of perennial grass holds great promise for the conversion of sustainable renewable feedstock to energy and other process intermediates. The advancement of this technology however, and its implementation for industrial applications, relies on a greater understanding of the microbiome underpinning the process. To this end, microbial communities recovered from replicated anaerobic bioreactors digesting grass were analyzed. The bioreactors leachates were not buffered and acidic pH (between 5.5 and 6.3) prevailed at the time of sampling as a result of microbial activities. Community composition and transcriptionally active taxa were examined using 16S rRNA sequencing and microbial functions were investigated using metaproteomics. Bioreactor fraction, i.e., grass or leachate, was found to be the main discriminator of community analysis across the three molecular level of investigation (DNA, RNA, and proteins). Six taxa, namely Bacteroidia, Betaproteobacteria, Clostridia, Gammaproteobacteria, Methanomicrobia, and Negativicutes accounted for the large majority of the three datasets. The initial stages of grass hydrolysis were carried out by Bacteroidia, Gammaproteobacteria, and Negativicutes in the grass biofilms, in addition to Clostridia in the

  2. Root growth and N dynamics in response to multi-year experimental warming, summer drought and elevated CO2 in a mixed heathland-grass ecosystem

    DEFF Research Database (Denmark)

    Arndal, M. F.; Schmidt, I. K.; Kongstad, J.

    2013-01-01

    growth would be matched by an increase in root nutrient uptake of NH4+-N and NO3- -N. Root growth was significantly increased by elevated CO2. The roots, however, did not fully compensate for the higher growth with a similar increase in nitrogen uptake per unit of root mass. Hence the nitrogen...... concentration in roots was decreased in elevated CO2, whereas the biomass N pool was unchanged or even increased. The higher net root production in elevated CO2 might be a strategy for the plants to cope with increased nutrient demand leading to a long-term increase in N uptake on a whole-plant basis. Drought...... reduced grass root biomass and N uptake, especially when combined with warming, but CO2 was the most pronounced main factor effect. Several significant interactions of the treatments were found, which indicates that the responses were nonadditive and that changes to multiple environmental changes cannot...

  3. Coping with low nutrient availability and inundation: root growth responses of three halophytic grass species from different elevations along a flooding gradient

    NARCIS (Netherlands)

    Bouma, T.J.; Koutstaal, B.P.; Van Dongen, M.; Nielsen, K.F.

    2001-01-01

    We describe the responses of three halophytic grass species that dominate the low (Spartina anglica), middle (Puccinellia maritima) and high (Elymus pycnanthus) parts of a salt marsh, to soil conditions that are believed to favour contrasting root-growth strategies. Our hypotheses were: (1)

  4. Coupling carbon allocation with leaf and root phenology predicts tree-grass partitioning along a savanna rainfall gradient

    Science.gov (United States)

    Haverd, V.; Smith, B.; Raupach, M.; Briggs, P.; Nieradzik, L.; Beringer, J.; Hutley, L.; Trudinger, C. M.; Cleverly, J.

    2016-02-01

    The relative complexity of the mechanisms underlying savanna ecosystem dynamics, in comparison to other biomes such as temperate and tropical forests, challenges the representation of such dynamics in ecosystem and Earth system models. A realistic representation of processes governing carbon allocation and phenology for the two defining elements of savanna vegetation (namely trees and grasses) may be a key to understanding variations in tree-grass partitioning in time and space across the savanna biome worldwide. Here we present a new approach for modelling coupled phenology and carbon allocation, applied to competing tree and grass plant functional types. The approach accounts for a temporal shift between assimilation and growth, mediated by a labile carbohydrate store. This is combined with a method to maximize long-term net primary production (NPP) by optimally partitioning plant growth between fine roots and (leaves + stem). The computational efficiency of the analytic method used here allows it to be uniquely and readily applied at regional scale, as required, for example, within the framework of a global biogeochemical model.We demonstrate the approach by encoding it in a new simple carbon-water cycle model that we call HAVANA (Hydrology and Vegetation-dynamics Algorithm for Northern Australia), coupled to the existing POP (Population Orders Physiology) model for tree demography and disturbance-mediated heterogeneity. HAVANA-POP is calibrated using monthly remotely sensed fraction of absorbed photosynthetically active radiation (fPAR) and eddy-covariance-based estimates of carbon and water fluxes at five tower sites along the North Australian Tropical Transect (NATT), which is characterized by large gradients in rainfall and wildfire disturbance. The calibrated model replicates observed gradients of fPAR, tree leaf area index, basal area, and foliage projective cover along the NATT. The model behaviour emerges from complex feedbacks between the plant

  5. Water use, root activity and deep drainage within a perennial legume-grass pasture: A case study in southern inland Queensland, Australia

    Directory of Open Access Journals (Sweden)

    A. Nahuel A. Pachas

    2016-09-01

    Full Text Available Water use and depth of water extraction of leucaena (Leucaena leucocephala and Rhodes grass (Chloris gayana pasture, irrigated with desalinated coal seam water (a by-product of the coal seam gas industry, were monitored to provide background information on root activity, spatial and temporal water use and deep drainage over a 757-day period from August 2011 to August 2013. Methodology comprised measurement of soil water from surface to 4 m depth using 8 EnviroSCAN probes connected to dataloggers positioned within leucaena twin rows and within the Rhodes grass inter-row. Just over 581,000 individual moisture measurements were collated and are reported here. Water extraction (and by inference root activity of leucaena and Rhodes grass showed marked seasonal fluctuation with deepest and highest water extraction occurring during the first growing season; water extraction was greatly diminished during the following drier and cooler seasons due to the negative influences of lower soil moisture contents, lower temperatures and increased defoliation on pasture growth. The highest values of deep drainage below 4 m depth occurred when high rainfall events corresponded with high soil water storage in the entire profile (0–4 m depth. Given that water usage by both leucaena and Rhodes grass was greatest in the upper layers of soil (<1.5 m, future research should focus on how the level of competitive interaction might be managed by choice of row spacing and frequency of irrigation. Further studies are needed, including: (a physical sampling to determine the depth of active roots; (b how defoliation affects rooting behaviours and water use of leucaena; and (c modelling of the water and salt balances of leucaena and grass inter-row systems using data from this study, with various levels of irrigation, to investigate the risks of deep drainage over an extended climate sequence.Keywords: Active rooting depth, agroforestry, Chloris gayana, Leucaena leucocephala

  6. Effect of competition and soil quality on root topology of the perennial grass Molinia caerulea

    Czech Academy of Sciences Publication Activity Database

    Janeček, Štěpán; Janečková, P.; Lepš, Jan

    2007-01-01

    Roč. 79, č. 1 (2007), s. 23-32 ISSN 0032-7786 R&D Projects: GA ČR GD206/03/H034 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z50070508 Keywords : Carex hartmanii * Holcus lanatus * Molinia caerulea * root Subject RIV: EF - Botanics Impact factor: 2.064, year: 2007

  7. Roots affect the response of heterotrophic soil respiration to temperature in tussock grass microcosms.

    Science.gov (United States)

    Graham, Scott L; Millard, Peter; Hunt, John E; Rogers, Graeme N D; Whitehead, David

    2012-07-01

    While the temperature response of soil respiration (R(S)) has been well studied, the partitioning of heterotrophic respiration (R(H)) by soil microbes from autotrophic respiration (R(A)) by roots, known to have distinct temperature sensitivities, has been problematic. Further complexity stems from the presence of roots affecting R(H), the rhizosphere priming effect. In this study the short-term temperature responses of R(A) and R(H) in relation to rhizosphere priming are investigated. Temperature responses of R(A), R(H) and rhizosphere priming were assessed in microcosms of Poa cita using a natural abundance δ(13)C discrimination approach. The temperature response of R(S) was found to be regulated primarily by R(A), which accounted for 70 % of total soil respiration. Heterotrophic respiration was less sensitive to temperature in the presence of plant roots, resulting in negative priming effects with increasing temperature. The results emphasize the importance of roots in regulating the temperature response of R(S), and a framework is presented for further investigation into temperature effects on heterotrophic respiration and rhizosphere priming, which could be applied to other soil and vegetation types to improve models of soil carbon turnover.

  8. Phytotoxic grass residues reduce germination and initial root growth of ponderosa pine

    Science.gov (United States)

    W. J. Rietveld

    1975-01-01

    Extracts of green foliage of Arizona fescue and mountain muhly significantly reduced germination of ponderosa pine seeds, and retarded speed of elongation and mean radicle length. Three possible routes of release of the inhibitor were investigated: (1) leaching from live foliage, (2) root exudation, and (3) overwinter leaching from dead residues. The principal route...

  9. Simplified and representative bacterial community of maize roots.

    Science.gov (United States)

    Niu, Ben; Paulson, Joseph Nathaniel; Zheng, Xiaoqi; Kolter, Roberto

    2017-03-21

    Plant-associated microbes are important for the growth and health of their hosts. As a result of numerous prior studies, we know that host genotypes and abiotic factors influence the composition of plant microbiomes. However, the high complexity of these communities challenges detailed studies to define experimentally the mechanisms underlying the dynamics of community assembly and the beneficial effects of such microbiomes on plant hosts. In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains ( Enterobacter cloacae , Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum , and Chryseobacterium indologenes ) representing three of the four most dominant phyla found in maize roots. By using a selective culture-dependent method to track the abundance of each strain, we investigated the role that each plays in community assembly on roots of axenic maize seedlings. Only the removal of E. cloacae led to the complete loss of the community, and C. pusillum took over. This result suggests that E. cloacae plays the role of keystone species in this model ecosystem. In planta and in vitro, this model community inhibited the phytopathogenic fungus Fusarium verticillioides , indicating a clear benefit to the host. Thus, combined with the selective culture-dependent quantification method, our synthetic seven-species community representing the root microbiome has the potential to serve as a useful system to explore how bacterial interspecies interactions affect root microbiome assembly and to dissect the beneficial effects of the root microbiota on hosts under laboratory conditions in the future.

  10. Roots of success: cultivating viable community forestry

    Energy Technology Data Exchange (ETDEWEB)

    MacQueen, Duncan

    2009-05-15

    Is community forestry emerging from the shadows? The evidence shows that locally controlled enterprises can be economically viable, and often build on stronger social and environmental foundations than the big private-sector players. Certainly this is an industry in need of a shakeup. Many forests have become flashpoints where agro-industry, large-scale logging concerns and conservation interests clash, while forest-dependent communities are left out in the cold. Meanwhile, governments – driven by concerns over the climate impacts of deforestation – are having to gear up for legal, sustainable forestry production. Community forestry could be crucial to solving many of these challenges. By building on local core capabilities and developing strategic partnerships, they are forging key new business models that could transform the sector.

  11. Identification and effect of two flavonoids from root bark of Morus alba against Ichthyophthirius multifiliis in grass carp.

    Science.gov (United States)

    Liang, Jing-Han; Fu, Yao-Wu; Zhang, Qi-Zhong; Xu, De-Hai; Wang, Bin; Lin, De-Jie

    2015-02-11

    Ichthyophthirius multifiliis (Ich) is an important ciliate that parasitizes gills and skin of freshwater fish and causes massive fish mortality. In this study, two flavonoids (kuwanons G and O) with anti-Ich activity were isolated by bioassay-guided fractionation from the root bark of Morus alba, an important plant for sericulture. The chemical structures of kuwanons G and O were elucidated by spectroscopic analyses. Kuwanons G and O caused 100% mortality of I. multifiliis theronts at the concentration of 2 mg/L and possessed a median effective concentration (EC50) of 0.8 ± 0.04 mg/L against the theronts. In addition, kuwanons G and O significantly reduced the infectivity of I. multifiliis theronts at concentrations of 0.125, 0.25, 0.5, and 1 mg/L. The median lethal concentrations (LC50) of kuwanons G and O to grass carp were 38.0 ± 0.82 and 26.9 ± 0.51 mg/L, which were approximately 50 and 35 times the EC50 for killing theronts. The results indicate that kuwanons G and O have the potential to become safe and effective drugs to control ichthyophthiriasis.

  12. Proteogenomic analyses indicate bacterial methylotrophy and archaeal heterotrophy are prevalent below the grass root zone

    Directory of Open Access Journals (Sweden)

    Cristina N. Butterfield

    2016-11-01

    Full Text Available Annually, half of all plant-derived carbon is added to soil where it is microbially respired to CO2. However, understanding of the microbiology of this process is limited because most culture-independent methods cannot link metabolic processes to the organisms present, and this link to causative agents is necessary to predict the results of perturbations on the system. We collected soil samples at two sub-root depths (10–20 cm and 30–40 cm before and after a rainfall-driven nutrient perturbation event in a Northern California grassland that experiences a Mediterranean climate. From ten samples, we reconstructed 198 metagenome-assembled genomes that represent all major phylotypes. We also quantified 6,835 proteins and 175 metabolites and showed that after the rain event the concentrations of many sugars and amino acids approach zero at the base of the soil profile. Unexpectedly, the genomes of novel members of the Gemmatimonadetes and Candidate Phylum Rokubacteria phyla encode pathways for methylotrophy. We infer that these abundant organisms contribute substantially to carbon turnover in the soil, given that methylotrophy proteins were among the most abundant proteins in the proteome. Previously undescribed Bathyarchaeota and Thermoplasmatales archaea are abundant in deeper soil horizons and are inferred to contribute appreciably to aromatic amino acid degradation. Many of the other bacteria appear to breakdown other components of plant biomass, as evidenced by the prevalence of various sugar and amino acid transporters and corresponding hydrolyzing machinery in the proteome. Overall, our work provides organism-resolved insight into the spatial distribution of bacteria and archaea whose activities combine to degrade plant-derived organics, limiting the transport of methanol, amino acids and sugars into underlying weathered rock. The new insights into the soil carbon cycle during an intense period of carbon turnover, including

  13. Plant litter effects on soil nutrient availability and vegetation dynamics: changes that occur when annual grasses invade shrub-steppe communities

    Science.gov (United States)

    Sheel Bansal; Roger L. Sheley; Bob Blank; Edward A. Vasquez

    2014-01-01

    Changes in the quantity and quality of plant litter occur in many ecosystems as they are invaded by exotic species, which impact soil nutrient cycling and plant community composition. Such changes in sagebrush-steppe communities are occurring with invasion of annual grasses (AG) into a perennial grass (PG) dominated system. We conducted a 5-year litter manipulation...

  14. Do shallow soil, low water availability, or their combination increase the competition between grasses with different root systems in karst soil?

    Science.gov (United States)

    Zhao, Yajie; Li, Zhou; Zhang, Jing; Song, Haiyan; Liang, Qianhui; Tao, Jianping; Cornelissen, Johannes H C; Liu, Jinchun

    2017-04-01

    Uneven soil depth and low water availability are the key limiting factors to vegetation restoration and reconstruction in limestone soils such as in vulnerable karst regions. Belowground competition will possibly increase under limited soil resources. Here, we investigate whether low resource availability (including shallow soil, low water availability, and shallow soil and low water availability combined) stimulates the competition between grasses with different root systems in karst soil, by assessing their growth response, biomass allocation, and morphological plasticity. In a full three-way factorial blocked design of soil depth by water availability by neighbor identity, we grew Festuca arundinacea (deep-rooted) and Lolium perenne (shallow-rooted) under normal versus shallow soil depth, high versus low water availability, and in monoculture (conspecific neighbor) versus mixture (neighbor of the other species). The key results were as follows: (1) total biomass and aboveground biomass in either of the species decreased with reduction of resources but were not affected by planting patterns (monoculture or mixture) even at low resource levels. (2) For F. arundinacea, root biomass, root mass fraction, total root length, and root volume were higher in mixture than in monoculture at high resource level (consistent with resource use complementarity), but lower in mixture than in monoculture at low resource levels (consistent with interspecific competition). In contrast for L. perenne, either at high or low resource level, these root traits had mostly similar values at both planting patterns. These results suggest that deep-rooted and shallow-rooted plant species can coexist in karst regions under current climatic regimes. Declining resources, due to shallow soil, a decrease in precipitation, or combined shallow soil and karst drought, increased the root competition between plants of deep-rooted and shallow-rooted species. The root systems of deep-rooted plants may be

  15. Diversity effects on root length production and loss in an experimental grassland community

    NARCIS (Netherlands)

    Mommer, L.; Padilla, F.M.; Ruijven, van J.; Caluwe, de H.; Smit-Tiekstra, A.E.; Berendse, F.; Kroon, de H.

    2015-01-01

    Advances in root ecology have revealed that root standing biomass is higher in species-rich plant communities than in species-poor communities. Currently, we do not know whether this below-ground diversity effect is the result of enhanced root production or reduced root mortality or both, which is

  16. Trait similarity patterns within grass and grasshopper communities : Multitrophic community assembly at work

    NARCIS (Netherlands)

    van der Plas, F.; Anderson, T. M.; Olff, H.

    Trait-based community assembly theory suggests that trait variation among co-occurring species is shaped by two main processes: abiotic filtering, important in stressful environments and promoting similarity, and competition, more important in productive environments and promoting dissimilarity.

  17. Belowground ecology of scarabs feeding on grass roots: current knowledge and future directions for management in Australasia

    Directory of Open Access Journals (Sweden)

    Adam eFrew

    2016-03-01

    Full Text Available Many scarab beetles spend the majority of their lives belowground as larvae, feeding on grass roots. Many of these larvae are significant pests, causing damage to crops and grasslands. Damage by larvae of the greyback cane beetle (Dermolepida albohirtum, for example, can cause financial losses of up to AU$40 million annually to the Australian sugarcane industry. We review the ecology of some scarab larvae in Australasia, focusing on three subfamilies; Dynastinae, Rutelinae and Melolonthinae, containing key pest species. Although considerable research on the control of some scarab pests has been carried out in Australasia, for some species, the basic biology and ecology remains largely unexplored. We synthesize what is known about these scarab larvae and outline key knowledge gaps to highlights future research directions with a view to improve pest management. We do this by presenting an overview of the scarab larval host plants and feeding behavior; the impacts of abiotic (temperature, moisture and fertilization and biotic (pathogens, natural enemies and microbial symbionts factors on scarab larvae and conclude with how abiotic and biotic factors can be applied in agriculture for improved pest management, suggesting future research directions.Several host plant microbial symbionts, such as arbuscular mycorrhizal fungi and endophytes, can improve plant tolerance to scarabs and reduce larval performance, which have shown promise for use in pest management. In addition to this, several microbial scarab pathogens have been isolated for commercial use in pest management with particularly promising results. The entomopathogenic fungus Metarhizium anisopliae caused a 50% reduction in cane beetle larvae while natural enemies such as entomopathogenic nematodes have also shown potential as a biocontrol. Continued research should focus on filling the gaps in the knowledge of the basic ecology and feeding behavior of scarab larval species within Australasia

  18. Status and use of important native grasses adapted to sagebrush communities

    Science.gov (United States)

    Thomas A. Jones; Steven R. Larson

    2005-01-01

    Due to the emphasis on restoration, native cool-season grass species are increasing in importance in the commercial seed trade in the Western U.S. Cultivated seed production of these native grasses has often been hampered by seed dormancy, seed shattering, and pernicious awns that are advantageous outside of cultivation. Relatively low seed yields and poor seedling...

  19. Summer water use by California coastal prairie grasses: fog, drought, and community composition.

    Science.gov (United States)

    Corbin, Jeffrey D; Thomsen, Meredith A; Dawson, Todd E; D'Antonio, Carla M

    2005-10-01

    Plants in the Mediterranean climate region of California typically experience summer drought conditions, but correlations between zones of frequent coastal fog inundation and certain species' distributions suggest that water inputs from fog may influence species composition in coastal habitats. We sampled the stable H and O isotope ratios of water in non-photosynthetic plant tissue from a variety of perennial grass species and soil in four sites in northern California in order to determine the proportion of water deriving from winter rains and fog during the summer. The relationship between H and O stable isotopes from our sample sites fell to the right of the local meteoric water line (LMWL) during the summer drought, providing evidence that evaporation of water from the soil had taken place prior to the uptake of water by vegetation. We developed a novel method to infer the isotope values of water before it was subjected to evaporation in which we used experimental data to calculate the slope of the deltaH versus deltaO line versus the LMWL. After accounting for evaporation, we then used a two-source mixing model to evaluate plant usage of fog water. The model indicated that 28-66% of the water taken up by plants via roots during the summer drought came from fog rather than residual soil water from winter rain. Fog use decreased as distance from the coast increased, and there were significant differences among species in the use of fog. Rather than consistent differences in fog use by species whose distributions are limited to the coast versus those with broader distributions, species responded individualistically to summer fog. We conclude that fogwater inputs can mitigate the summer drought in coastal California for many species, likely giving an advantage to species that can use it over species that cannot.

  20. Diversity and aggregation patterns of plant species in a grass community

    Directory of Open Access Journals (Sweden)

    Ran Li

    2014-09-01

    Full Text Available Both composition and aggregation patterns of species in a community are the outcome of community self-organizing. In this paper we conducted analysis on species diversity and aggregation patterns of plant species in a grass community, Zhuhai, China. According to the sampling survey, in total of 47 plant species, belonging to 16 families, were found. Compositae had 10 species (21.3%, seconded by Gramineae (9 species, 19.1%, Leguminosae (6 species, 12.8%, Cyperaceae (4 species, 8.5%, and Malvaceae (3 species, 6.4%. The results revealed that the means of aggregation indices Iδ, I and m*/m were 21.71, 15.71 and 19.89 respectively and thus individuals of most of plant species strongly followed aggregative distribution. Iwao analysis indicated that both individuals of all species and clumps of all individuals of all species followed aggregative distribution. Taylor's power law indicated that individuals of all species followed aggregative distribution and aggregation intensity strengthened as the increase of mean density. We held that the strong aggregation intensity of a species has been resulted from the strong adaptation ability to the environment, the strong interspecific competition ability and the earlier establishment of the species. Fitting goodness of the mean, I, Iδ, m*/m with probability distributions demonstrated that the mean (density, I, Iδ, and m*/m over all species followed Weibull distribution rather than normal distribution. Lophatherum gracile, Paederia scandens (Lour. Merr., Eleusine indica, and Alternanthera philoxeroides (Mart. Griseb. were mostly aggregative, and Oxalis sp., Eleocharis plantagineiformis, Vernonia cinerea (L. Less., and Sapium sebiferum (L. Roxb, were mostly uniform in the spatial distribution. Importance values (IV showed that Cynodon dactylon was the most important species, seconded by Desmodium triflorum (L. DC., Cajanus scarabaeoides (L. Benth., Paspalum scrobiculatum L., and Rhynchelytrum repens. Oxalis

  1. Micro-PIXE mapping of elemental distribution in arbuscular mycorrhizal roots of the grass, Cynodon dactylon, from gold and uranium mine tailings

    Science.gov (United States)

    Weiersbye, I. M.; Straker, C. J.; Przybylowicz, W. J.

    1999-10-01

    A combination of PIXE, proton back-scattering (BS) spectrometry and confocal laser scanning microscopy (CLSM) was used to determine in situ elemental concentrations in arbuscular mycorrhizal (AM) grass roots and AM fungal spores from gold and uranium mine tailings in South Africa. AM regions of roots were characterised by locally elevated P and vesicles were defined by distinctive transition metal and radionuclide distributions. Vesicles (AM structures responsible for nutrient storage), accumulated Mn, Cu, Ni and U, whereas Fe and Zn were present at lower levels than in host tissue. AM spores from mine tailings accumulated Ca, Cr, Fe, Ni, Cu, Br, Y, Th and U, but were deficient in P and K. The sequestration of excess metals and radionuclides in vesicles may limit metal availability, and thus toxicity, to the host.

  2. Micro-PIXE mapping of elemental distribution in arbuscular mycorrhizal roots of the grass, Cynodon dactylon, from gold and uranium mine tailings

    Energy Technology Data Exchange (ETDEWEB)

    Weiersbye, I.M. E-mail: isabel@gecko.biol.wits.ac.za; Straker, C.J.; Przybylowicz, W.J

    1999-09-02

    A combination of PIXE, proton back-scattering (BS) spectrometry and confocal laser scanning microscopy (CLSM) was used to determine in situ elemental concentrations in arbuscular mycorrhizal (AM) grass roots and AM fungal spores from gold and uranium mine tailings in South Africa. AM regions of roots were characterised by locally elevated P and vesicles were defined by distinctive transition metal and radionuclide distributions. Vesicles (AM structures responsible for nutrient storage), accumulated Mn, Cu, Ni and U, whereas Fe and Zn were present at lower levels than in host tissue. AM spores from mine tailings accumulated Ca, Cr, Fe, Ni, Cu, Br, Y, Th and U, but were deficient in P and K. The sequestration of excess metals and radionuclides in vesicles may limit metal availability, and thus toxicity, to the host.

  3. Micro-PIXE mapping of elemental distribution in arbuscular mycorrhizal roots of the grass, Cynodon dactylon, from gold and uranium mine tailings

    International Nuclear Information System (INIS)

    Weiersbye, I.M.; Straker, C.J.; Przybylowicz, W.J.

    1999-01-01

    A combination of PIXE, proton back-scattering (BS) spectrometry and confocal laser scanning microscopy (CLSM) was used to determine in situ elemental concentrations in arbuscular mycorrhizal (AM) grass roots and AM fungal spores from gold and uranium mine tailings in South Africa. AM regions of roots were characterised by locally elevated P and vesicles were defined by distinctive transition metal and radionuclide distributions. Vesicles (AM structures responsible for nutrient storage), accumulated Mn, Cu, Ni and U, whereas Fe and Zn were present at lower levels than in host tissue. AM spores from mine tailings accumulated Ca, Cr, Fe, Ni, Cu, Br, Y, Th and U, but were deficient in P and K. The sequestration of excess metals and radionuclides in vesicles may limit metal availability, and thus toxicity, to the host

  4. Determination Of Uncultured Endo phytic Bacterial Community From Rice Root

    International Nuclear Information System (INIS)

    Ying, P.L.W.; Jong, B.C.

    2013-01-01

    Culture-independent approaches were developed for rapid analysis of microbial community diversity in various environments. Direct analysis based on 16S rDNA as the phylogenetic markers is the most ordinary, conventional and suitable methods for bacterial diversity analysis. The objective of this study is to investigate the microbial diversity from the rice root tissues using culture-independent approach by 16S rDNA library construction. The 16S rDNAs were directly extracted from a total genomic DNA by polymerase chain reaction (PCR) amplification using with the bacteria-specific primer set. The 16S rDNAs were subsequently analysed by cloning and restriction digestion. The amplified ribosomal DNA restriction analysis (ARDRA) clustered the 16S rDNAs into eight majority patterns. These predominant patterns were analysed by DNA sequencing. A better understanding at microbial diversity level is critical to potentiate the endophyte as plant growth promoters. (author)

  5. Changes in the spore numbers of AM fungi and in AM colonisation of roots of clovers and grasses on a peat-muck soil with respect to mineral fertilization

    International Nuclear Information System (INIS)

    Kowalska, T. K.; Kwiatkowaska, E.

    2016-01-01

    A 4-year plot experiment was conducted to determine the dynamics of changes in the spore density of arbuscular mycorrhizal fungi (AMF) and of the degree of endomycorrhizal colonisation of roots of clovers and meadow grasses on an organic peat-muck soil in a post-marshy habitat, taking into account the effect of mineral fertilisation (NPK). The experimental object comprised four plots that represented the fertilisation treatments, sown with white clover (Trifolium repens L.), red clover (Trifolium pratense L.), smooth meadow-grass (Poa pratensis L.), and a mix of grasses composed of perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis Huds.), smooth meadow-grass (Poa pratensis L.), and cocksfoot (Dactylis glomerata L.). Analogous sowing was performed on control (non-fertilised) plots. It was found that spores of AMF occurred in 100 percent of the samples of the soil studied, and the average total number of AMF spores isolated from soil under the particular plant combinations was high and amounted to 1858 spores (range from 1392 to 2443) in 100 g of air-dried soil. The percentage share of the clover and grass roots colonised by indigenous endomycorrhizal fungi was very low and varied from 0 to 46 (average from 4.1 percent to 12.2 percent). No correlation was found between the spore numbers of AMF in the soil and the degree of mycorrhized roots of the clovers and grasses. Mineral fertilisation stimulated the sporulation of AM fungi but had no effect on root colonisation by these fungi. (author)

  6. Rhizosphere microbial community structure in relation to root location and plant iron nutritional status.

    Science.gov (United States)

    Yang, C H; Crowley, D E

    2000-01-01

    Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. To examine this question, we performed an experiment with barley (Hordeum vulgare) plants under iron-limiting and iron-sufficient growth conditions. Plants were grown in an iron-limiting soil in root box microcosms. One-half of the plants were treated with foliar iron every day to inhibit phytosiderophore production and to alter root exudate composition. After 30 days, the bacterial communities associated with different root zones, including the primary root tips, nonelongating secondary root tips, sites of lateral root emergence, and older roots distal from the tip, were characterized by using 16S ribosomal DNA (rDNA) fingerprints generated by PCR-denaturing gradient gel electrophoresis (DGGE). Our results showed that the microbial communities associated with the different root locations produced many common 16S rDNA bands but that the communities could be distinguished by using correspondence analysis. Approximately 40% of the variation between communities could be attributed to plant iron nutritional status. A sequence analysis of clones generated from a single 16S rDNA band obtained at all of the root locations revealed that there were taxonomically different species in the same band, suggesting that the resolving power of DGGE for characterization of community structure at the species level is limited. Our results suggest that the bacterial communities in the rhizosphere are substantially different in different root zones and that a rhizosphere community may be altered by changes in root exudate composition caused by changes in plant iron nutritional status.

  7. TEMPORALLY VARIABLE GEOGRAPHICAL DISTANCE EFFECTS CONTRIBUTE TO THE ASSEMBLY OF ROOT-ASSOCIATED FUNGAL COMMUNITIES

    Directory of Open Access Journals (Sweden)

    Christopher James Barnes

    2016-02-01

    Full Text Available Root-associated fungi are key contributors to ecosystem functioning, however the factors which determine community assembly are still relatively poorly understood. This study simultaneously quantified the roles of geographical distance, environmental heterogeneity and time in determining root-associated fungal community composition at the local scale within a short rotation coppice (SRC willow plantation. Culture independent molecular analyses of the root-associated fungal community suggested a strong but temporally variable effect of geographical distance between fungal communities on composition at the local geographical level. Whilst these distance effects were most prevalent on October communities, soil pH had an effect on structuring of the communities throughout the sampling period. Given the temporal variation in the effects of geographical distance and the environment for shaping root-associated fungal communities, there is clearly need for a temporal component to sampling strategies in future investigations of fungal biogeography.

  8. Identification and effect of two flavonoids from root bark of Morus alba against Ichthyophthirius multifiliis in grass carp

    Science.gov (United States)

    Morus alba is an important plant for sericulture and has a high medicinal value. In this study, two flavonoids (kuwanons G and O) with antiparasitic activity were isolated from the root bark of M. alba by bioassay-guided fractionation. The chemical structures were determined by pectroscopic analys...

  9. Modern parameters of caesium-137 root uptake in natural and agricultural grass ecosystems of contaminated post-Chernobyl landscape, Russia

    Directory of Open Access Journals (Sweden)

    Tatiana Paramonova

    2015-01-01

    Full Text Available The estimation of modern parameters of 137Cs root uptake was conducted in natural meadow and agricultural ecosystems of post-Chernobyl landscapes of Tula region. The agrosystems with main crops of field rotation (barley, potatoes, rape, maize occupying watersheds and slopes with arable chernozems are contaminated at a level 460-670 Bq/kg (4.7-6.0 Ci/km2; natural meadow ecosystems occupying lower parts of slopes and floodplains are contaminated at a level 620-710 Bq/kg (5.8-7.6 Ci/km2. In the arable soils 137Cs uniformly distributed to a depth of Ap horizon (20-30 cm of thickness, while in meadow soils 70-80% of the radionuclide is concentrated within the top Ad horizon (9-13 cm of thickness. These topsoil layer accords with rhizosphere zone, where >80-90% of plant roots are concentrated, and from which 137Cs is mostly consumed by vegetation. Total amount of 137Cs root uptake depends on the level of soil radioactive contamination (correlation coefficient 0.61. So 137Cs activity in meadow vegetation (103-160 Bq/kg is generally more than one in agricultural vegetation (9-92 Bq/kg. The values of 137Cs transfer factor in the studied ecosystems vary from 0.01 (rape to 0.20 (wet meadow, that confirms the discrimination of the radionuclide’s root uptake. The larger are the volume of roots and their absorbing surface, the higher are the values of transfer factor from soil to plant (correlation coefficients 0.71 and 0.64 respectively. 137Cs translocation from roots to shoots is also determined by biological features of plants. At the same level of soil contamination above-ground parts of meadow herbs accumulate more 137Cs than Gramineae species, and in agrosystems above-ground parts of weeds concentrate more 137Cs than cultivated cereals. Thus, the level of soil radioactive pollution and biological features of plants are determinants in the process of 137Cs root uptake and translocation and should be considered in land use policy.

  10. Root nodule symbiosis in Lotus japonicus drives the establishment of distinctive rhizosphere, root, and nodule bacterial communities.

    Science.gov (United States)

    Zgadzaj, Rafal; Garrido-Oter, Ruben; Jensen, Dorthe Bodker; Koprivova, Anna; Schulze-Lefert, Paul; Radutoiu, Simona

    2016-12-06

    Lotus japonicus has been used for decades as a model legume to study the establishment of binary symbiotic relationships with nitrogen-fixing rhizobia that trigger root nodule organogenesis for bacterial accommodation. Using community profiling of 16S rRNA gene amplicons, we reveal that in Lotus, distinctive nodule- and root-inhabiting communities are established by parallel, rather than consecutive, selection of bacteria from the rhizosphere and root compartments. Comparative analyses of wild-type (WT) and symbiotic mutants in Nod factor receptor5 (nfr5), Nodule inception (nin) and Lotus histidine kinase1 (lhk1) genes identified a previously unsuspected role of the nodulation pathway in the establishment of different bacterial assemblages in the root and rhizosphere. We found that the loss of nitrogen-fixing symbiosis dramatically alters community structure in the latter two compartments, affecting at least 14 bacterial orders. The differential plant growth phenotypes seen between WT and the symbiotic mutants in nonsupplemented soil were retained under nitrogen-supplemented conditions that blocked the formation of functional nodules in WT, whereas the symbiosis-impaired mutants maintain an altered community structure in the nitrogen-supplemented soil. This finding provides strong evidence that the root-associated community shift in the symbiotic mutants is a direct consequence of the disabled symbiosis pathway rather than an indirect effect resulting from abolished symbiotic nitrogen fixation. Our findings imply a role of the legume host in selecting a broad taxonomic range of root-associated bacteria that, in addition to rhizobia, likely contribute to plant growth and ecological performance.

  11. Study of the spatial distribution of mercury in roots of vetiver grass (Chrysopogon zizanioides) by micro-pixe spectrometry.

    Science.gov (United States)

    Lomonte, Cristina; Wang, Yaodong; Doronila, Augustine; Gregory, David; Baker, Alan J M; Siegele, Rainer; Kolev, Spas D

    2014-01-01

    Localization of Hg in root tissues of vetivergrass (Chrysopogon zizanioides) was investigated by micro-Proton Induced X-ray Emission (PIXE) spectrometry to gain a better understanding of Hg uptake and its translocation to the aerial plant parts. Tillers of C. zizanioides were grown in a hydroponic culture for 3 weeks under controlled conditions and then exposed to Hg for 10 days with or without the addition of the chelators (NH(4))(2)S(2)O(3) or KI. These treatments were used to study the effects of these chelators on localization of Hg in the root tissues to allow better understanding of Hg uptake during its assisted-phytoextraction. Qualitative elemental micro-PIXE analysis revealed that Hg was mainly localized in the root epidermis and exodermis, tissues containing suberin in all Hg treatments. Hg at trace levels was localized in the vascular bundle when plants were treated with a mercury solution only. However, higher Hg concentrations were found when the solution also contained (NH(4))(2)S(2)O(3) or KI. This finding is consistent with the observed increase in Hg translocation to the aerial parts of the plants in the case of chemically induced Hg phytoextraction.

  12. Extreme rainfall affects assembly of the root-associated fungal community

    DEFF Research Database (Denmark)

    Barnes, Christopher James; van der Gast, Christopher J.; McNamara, Niall P.

    2018-01-01

    -associated fungus community of a short rotation coppice willow plantation, and compared community dynamics before and after a once in 100 yr rainfall event that occurred in the UK in 2012. Monitoring of the root-associated fungi was performed over a 3-yr period by metabarcoding the fungal internal transcribed...... yet overlooked determinants of root-associated fungal community assembly. Given the integral role of ectomycorrhizal fungi in biogeochemical cycles, these events may have considerable impacts upon the functioning of terrestrial ecosystems....

  13. Root-associated fungal community response to drought-associated changes in vegetation community.

    Science.gov (United States)

    Dean, Sarah L; Warnock, Daniel D; Litvak, Marcy E; Porras-Alfaro, Andrea; Sinsabaugh, Robert

    2015-01-01

    Recent droughts in southwestern USA have led to large-scale mortality of piñon (Pinus edulis) in piñon-juniper woodlands. Piñon mortality alters soil moisture, nutrient and carbon availability, which could affect the root-associated fungal (RAF) communities and therefore the fitness of the remaining plants. We collected fine root samples at a piñon-juniper woodland and a juniper savannah site in central New Mexico. Roots were collected from piñon and juniper (Juniperus monosperma) trees whose nearest neighbors were live piñon, live juniper or dead piñon. RAF communities were analyzed by 454 pyrosequencing of the universal fungal ITS region. The most common taxa were Hypocreales and Chaetothyriales. More than 10% of ITS sequences could not be assigned taxonomy at the phylum level. Two of the unclassified OTUs significantly differed between savanna and woodland, had few like sequences in GenBank and formed new fungal clades with other unclassified RAF from arid plants, highlighting how little study has been done on the RAF of arid ecosystems. Plant host or neighbor did not affect RAF community composition. However, there was a significant difference between RAF communities from woodland vs. savanna, indicating that abiotic factors such as temperature and aridity might be more important in structuring these RAF communities than biotic factors such as plant host or neighbor identity. Ectomycorrhizal fungi (EM) were present in juniper as well as piñon in the woodland site, in contrast with previous research, but did not occur in juniper savanna, suggesting a potential shared EM network with juniper. RAF richness was lower in hosts that were neighbors of the opposite host. This may indicate competitive exclusion between fungi from different hosts. Characterizing these communities and their responses to environment and plant neighborhood is a step toward understanding the effects of drought on a biome that spans 19,000,000 ha of southwestern USA. © 2015 by The

  14. Organic fertilization alters the community composition of root associated fungi in Pisum sativum

    DEFF Research Database (Denmark)

    Yu, L.; Nicolaisen, M.; Ravnskov, S.

    2013-01-01

    Organic fertilization is well known to affect individual functional groups of root associated fungi such as arbuscular mycorrhizal (AM) fungi and root pathogens, but limited information is available on the effect of organic fertilization at the fungal community composition level. The main objective...... of the present study was to examine the response of communities of root associated fungi in Pisum sativum to Protamylasse, an organic fertilizer used in pea production. Plants were grown in pots with field soil amended with four different levels of Protamylasse. 454 pyrosequencing was employed to examine......, the organic fertilizer Protamylasse clearly affects communities of root associated fungi, which seems to be linked to the life strategy of the different functional groups of root associated fungi. --------------------------------------------------------------------------------...

  15. Community-Weighted Mean Plant Traits Predict Small Scale Distribution of Insect Root Herbivore Abundance.

    Directory of Open Access Journals (Sweden)

    Ilja Sonnemann

    Full Text Available Small scale distribution of insect root herbivores may promote plant species diversity by creating patches of different herbivore pressure. However, determinants of small scale distribution of insect root herbivores, and impact of land use intensity on their small scale distribution are largely unknown. We sampled insect root herbivores and measured vegetation parameters and soil water content along transects in grasslands of different management intensity in three regions in Germany. We calculated community-weighted mean plant traits to test whether the functional plant community composition determines the small scale distribution of insect root herbivores. To analyze spatial patterns in plant species and trait composition and insect root herbivore abundance we computed Mantel correlograms. Insect root herbivores mainly comprised click beetle (Coleoptera, Elateridae larvae (43% in the investigated grasslands. Total insect root herbivore numbers were positively related to community-weighted mean traits indicating high plant growth rates and biomass (specific leaf area, reproductive- and vegetative plant height, and negatively related to plant traits indicating poor tissue quality (leaf C/N ratio. Generalist Elaterid larvae, when analyzed independently, were also positively related to high plant growth rates and furthermore to root dry mass, but were not related to tissue quality. Insect root herbivore numbers were not related to plant cover, plant species richness and soil water content. Plant species composition and to a lesser extent plant trait composition displayed spatial autocorrelation, which was not influenced by land use intensity. Insect root herbivore abundance was not spatially autocorrelated. We conclude that in semi-natural grasslands with a high share of generalist insect root herbivores, insect root herbivores affiliate with large, fast growing plants, presumably because of availability of high quantities of food. Affiliation of

  16. Extending professional education to health workers at grass root level: An experience from All India Institute of Medical Sciences, New Delhi

    Directory of Open Access Journals (Sweden)

    K K Deepak

    2014-01-01

    Full Text Available Background: In India, the opportunities for professional education of the grass root level health workers are grossly inadequate. Capacity building of all categories of health workers is needed for enhancing health outcomes. Objectives: To plan and implement a professional development training program for all categories of allied health workers and to assess its outcomes in terms of knowledge and skills Materials and Method: We planned and organized a ′one week′(15 h training program for 10 categories of allied health workers (1260 working in our hospital. The program included nine generic skills/topics: the prestige of AIIMS, sterilization & infection control, universal precaution, biomedical waste management, public health, life style & healthy nutrition, fire safety, communication skills and office procedure besides subject specific skills. Trainers were drawn from 12 departments. Training methodology included interactive lectures, narratives, demonstrations, videos, PPT slides, and informal discussions with participants. The effectiveness of the program was judged on the basis of participants′ feedback, feedback from the supervisors, and our own observations post training. Results: Feedback from the participants and their supervisors after training was encouraging. The participants described training as a "life time experience". The supervisors reported improvement in confidence, communication skills, and awareness of workers. Conclusion: The success of the program was due to the use of interactive methods, involvement of multidisciplinary team, and commitment from leadership. We recommend that professional education should be linked with career advancement. Academic institutions can play a key role in taking such initiatives.

  17. 浅谈图书馆基础竞合层策略%On the Strategy of Grass-Root Competition and Cooperation Based on the Library

    Institute of Scientific and Technical Information of China (English)

    吕春晖

    2011-01-01

    The competition is based on the library cooperation within competition.This grass-roots cooperation and competition exists in every business process within the work areas.Modern Library's management should change their ideas,based on reality,the development of the strategic objectives for their own development,in order to improve their market competitiveness. This paper analyzes the level of the library-based competition and cooperation of several key strategies.%图书馆竞争的基础是内部的合作竞争。这种基层合作与竞争存在于内部的每一个业务流程、工作环节。现代图书馆的管理应该转变观念,立足实际,制定适合自身发展的战略目标,才能提高自身的市场竞争力。本文分析了图书馆基础竞争合作层面的几个主要策略。

  18. Effect of water and nitrogen additions on free-living nitrogen fixer populations in desert grass root zones.

    Science.gov (United States)

    Herman, R P; Provencio, K R; Torrez, R J; Seager, G M

    1993-01-01

    In this study we measured changes in population levels of free-living N2-fixing bacteria in the root zones of potted Bouteloua eriopoda and Sporobolus flexuosus plants as well as the photosynthetic indices of the plants in response to added nitrogen, added water, and added water plus nitrogen treatments. In addition, N2 fixer population changes in response to added carbon source and nitrogen were measured in plant-free soil columns. There were significant increases in the numbers of N2 fixers associated with both plant species in the water and the water plus nitrogen treatments. Both treatments increased the photosynthetic index, suggesting that plant exudates were driving N2 fixer population changes. Population increases were greatest in the water plus nitrogen treatments, indicating that added nitrogen was synergistic with added water and suggesting that nitrogen addition spared bacteria the metabolic cost of N2 fixation, allowing greater reproduction. Plant-free column studies demonstrated a synergistic carbon-nitrogen effect when carbon levels were limiting (low malate addition) but not when carbon was abundant (high malate), further supporting this hypothesis. The results of this study indicate the presence of N2 fixer populations which interact with plants and which may play a role in the nitrogen balance of desert grasslands. PMID:8215373

  19. A new emphasis on root traits for perennial grass and legume varieties with environmental and ecological benefits.

    Science.gov (United States)

    Marshall, Athole H; Collins, Rosemary P; Humphreys, Mike W; Scullion, John

    2016-02-01

    Grasslands cover a significant proportion of the agricultural land within the UK and across the EU, providing a relatively cheap source of feed for ruminants and supporting the production of meat, wool and milk from grazing animals. Delivering efficient animal production from grassland systems has traditionally been the primary focus of grassland-based research. But there is increasing recognition of the ecological and environmental benefits of these grassland systems and the importance of the interaction between their component plants and a host of other biological organisms in the soil and in adjoining habitats. Many of the ecological and environmental benefits provided by grasslands emanate from the interactions between the roots of plant species and the soil in which they grow. We review current knowledge on the role of grassland ecosystems in delivering ecological and environmental benefits. We will consider how improved grassland can deliver these benefits, and the potential opportunities for plant breeding to improve specific traits that will enhance these benefits whilst maintaining forage production for livestock consumption. Opportunities for exploiting new plant breeding approaches, including high throughput phenotyping, and for introducing traits from closely related species are discussed.

  20. An experimental analysis of grasshopper community responses to fire and livestock grazing in a northern mixed-grass prairie.

    Science.gov (United States)

    Branson, David H; Sword, Gregory A

    2010-10-01

    The outcomes of grasshopper responses to both vertebrate grazing and fire vary across grassland ecosystems, and are strongly influenced by local climactic factors. Thus, the possible application of grazing and fire as components of an ecologically based grasshopper management strategy must be investigated in regional studies. In this study, we examined the effects of grazing and fire on grasshopper population density and community composition in a northern Great Plains mixed-grass prairie. We employed a large-scale, replicated, and fully-factorial manipulative experimental design across 4 yr to examine the separate and interactive effects of three grazing systems in burned and unburned habitats. Grasshopper densities were low throughout the 4-yr study and 1 yr of pretreatment sampling. There was a significant fire by grazing interaction effect on cumulative density and community composition, resulting from burned season long grazing pastures having higher densities than unburned pastures. Shannon diversity and grasshopper species richness were significantly higher with twice-over rotational livestock grazing. The ability to draw strong conclusions regarding the nature of species composition shifts and population changes in the presence of fire and grazing is complicated by the large site differences and low grasshopper densities. The results reinforce the importance of long-term research to examine the effects of habitat manipulation on grasshopper population dynamics.

  1. Kinetics of caesium and potassium absorption by roots of three grass pastures and competitive effects of potassium on caesium uptake in Cynodon sp.

    Science.gov (United States)

    Ayub, J. Juri; Valverde, L. Rubio; Garcia-Sanchez, M. J.; Fernandez, J. A.; Velasco, R. H.

    2008-08-01

    Caesium uptake by plant roots has been normally associated with the uptake of potassium as the potassium transport systems present in plants have also the capacity to transport caesium. Three grass species (Eragrostis curvula, Cynodon sp and Distichlis spicata) growing in seminatural grassland of central Argentina were selected to study their capability to incorporate Cs+ (and K+) using electrophysiological techniques. Although the 137Cs soil inventory ranged between 328-730 Bq m-2 in this region, no 137Cs activity was detected in these plants. However, all the species, submitted previously to K+ starvation, showed the uptake of both Cs+ and K+ when micromolar concentrations of these cations were present in the medium. The uptake showed saturation kinetics for both cations that could be fitted to the Michelis-Menten model. KM values were smaller for K+ than for Cs+, indicating a higher affinity for the first cation. The presence of increasing K+ concentrations in the assay medium inhibited Cs+ uptake in Cynodon sp., as expected if both cations are transported by the same transport systems. This effect is due to the competition of both ions for the union sites of the high affinity potassium transporters. In field situation, where soil concentration of Cs+ is smaller than K+ concentration, is then expectable that caesium activity in plants is not detectable. Nevertheless, the studied plants would have the capacity to incorporate caesium if its availability in soil solution increases. In addition, studies of Cs/K interaction can help us to understand the variability in transfer factors.

  2. Kinetics of caesium and potassium absorption by roots of three grass pastures and competitive effects of potassium on caesium uptake in Cynodon sp

    International Nuclear Information System (INIS)

    Ayub, J. Juri; Velasco, R. H.; Valverde, L. Rubio; Garcia-Sanchez, M. J.; Fernandez, J. A.

    2008-01-01

    Caesium uptake by plant roots has been normally associated with the uptake of potassium as the potassium transport systems present in plants have also the capacity to transport caesium. Three grass species (Eragrostis curvula, Cynodon sp and Distichlis spicata) growing in seminatural grassland of central Argentina were selected to study their capability to incorporate Cs + (and K + ) using electrophysiological techniques. Although the 137 Cs soil inventory ranged between 328-730 Bq m -2 in this region, no 137 Cs activity was detected in these plants. However, all the species, submitted previously to K + starvation, showed the uptake of both Cs + and K + when micromolar concentrations of these cations were present in the medium. The uptake showed saturation kinetics for both cations that could be fitted to the Michelis-Menten model. K M values were smaller for K + than for Cs + , indicating a higher affinity for the first cation. The presence of increasing K + concentrations in the assay medium inhibited Cs + uptake in Cynodon sp., as expected if both cations are transported by the same transport systems. This effect is due to the competition of both ions for the union sites of the high affinity potassium transporters. In field situation, where soil concentration of Cs + is smaller than K + concentration, is then expectable that caesium activity in plants is not detectable. Nevertheless, the studied plants would have the capacity to incorporate caesium if its availability in soil solution increases. In addition, studies of Cs/K interaction can help us to understand the variability in transfer factors

  3. Root-derived organic matter confines sponge community composition in mangrove ecosystems

    NARCIS (Netherlands)

    Hunting, E.R.; Ubels, S.M.; Kraak, M.H.S.; van der Geest, H.G.

    2013-01-01

    Introduction Caribbean mangrove-associated sponge communities are very distinct from sponge communities living on nearby reefs, but the mechanisms that underlie this distinction remain uncertain. It has been hypothesized that dissolved organic matter (DOM) leaching from mangrove roots and the

  4. [Effects of wheat root exudates on cucumber growth and soil fungal community structure].

    Science.gov (United States)

    Wu, Feng-Zhi; Li, Min; Cao, Peng; Ma, Ya-Fei; Wang, Li-Li

    2014-10-01

    With wheat as the donor plant and cucumber as the receptor plant, this study investigated the effects of root exudates from wheat cultivars with different allelopathic potentials (positive or negative) and companion cropping with wheat on soil fungal community structure by PCR-DGGE method and cucumber growth. Results showed that the wheat root exudates with positive allelopathic potential increased height and stem diameter of cucumber seedlings significantly, compared to the control seedlings (W) after 6 days and 12 days treatment, respectively. Also, wheat root exudates with both positive and negative allelopathic potential increased the seedling height of cucumber significantly after 18 days treatment. The wheat root exudates with different allelopathic potentials decreased the band number, Shannon and evenness indices of soil fungal community significantly in cucumber seedling rhizosphere, and those in the soil with the control seedlings (W) were also significantly higher than that in the control soil without seedlings (Wn) after 6 days treatment. The band number, Shannon and evenness indices in all the treatments were significantly higher than those in the control soil without seedlings (Wn) after 18 days treatment. Companion cropping with negative allelopathic potential wheat decreased the Shannon and evenness indices of soil fungi community significantly in the cucumber seedling rhizosphere, suggesting the wheat root exudates and companion cropping with wheat changed soil fungal community structure in the cucumber seedling rhizosphere. The results of DGGE map and the principal component analysis showed that companion cropping with wheat cultivars with different allelopathic potentials changed soil fungal community structure in cucumber seedling rhizosphere.

  5. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants.

    Directory of Open Access Journals (Sweden)

    Martina Janoušková

    Full Text Available Inoculation with arbuscular mycorrhizal fungi (AMF may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation.

  6. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants

    Science.gov (United States)

    Krak, Karol; Vosátka, Miroslav; Püschel, David; Štorchová, Helena

    2017-01-01

    Inoculation with arbuscular mycorrhizal fungi (AMF) may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation. PMID:28738069

  7. Community composition of root-associated fungi in a Quercus-dominated temperate forest: “codominance” of mycorrhizal and root-endophytic fungi

    Science.gov (United States)

    Toju, Hirokazu; Yamamoto, Satoshi; Sato, Hirotoshi; Tanabe, Akifumi S; Gilbert, Gregory S; Kadowaki, Kohmei

    2013-01-01

    In terrestrial ecosystems, plant roots are colonized by various clades of mycorrhizal and endophytic fungi. Focused on the root systems of an oak-dominated temperate forest in Japan, we used 454 pyrosequencing to explore how phylogenetically diverse fungi constitute an ecological community of multiple ecotypes. In total, 345 operational taxonomic units (OTUs) of fungi were found from 159 terminal-root samples from 12 plant species occurring in the forest. Due to the dominance of an oak species (Quercus serrata), diverse ectomycorrhizal clades such as Russula, Lactarius, Cortinarius, Tomentella, Amanita, Boletus, and Cenococcum were observed. Unexpectedly, the root-associated fungal community was dominated by root-endophytic ascomycetes in Helotiales, Chaetothyriales, and Rhytismatales. Overall, 55.3% of root samples were colonized by both the commonly observed ascomycetes and ectomycorrhizal fungi; 75.0% of the root samples of the dominant Q. serrata were so cocolonized. Overall, this study revealed that root-associated fungal communities of oak-dominated temperate forests were dominated not only by ectomycorrhizal fungi but also by diverse root endophytes and that potential ecological interactions between the two ecotypes may be important to understand the complex assembly processes of belowground fungal communities. PMID:23762515

  8. [Microbial Community Structure on the Root Surface of Patients with Periodontitis.

    Science.gov (United States)

    Zhang, Ju-Mei; Zhou, Jian-Ye; Bo, Lei; Hu, Xiao-Pan; Jiao, Kang-Li; Li, Zhi-Jie; Li, Yue-Hong; Li, Zhi-Qiang

    2016-11-01

    To study the microbial community structure on the root surface of patients with periodontitis. Bacterial plaque and tissues from the root neck (RN group),root middle (RM group) and root tine (RT group) of six teeth with mobility 3 in one patient with periodontitis were sampled.The V3V4 region of 16S rRNA was sequenced on the Illumina MiSeq platform.The microbial community structure was analyzed by Mothur,Qiime and SPSS software. The principal component analysis (PCoA) results indicated that the RM samples had a similar microbial community structure as that of the RT samples,which was significant different from that of the RN samples.Thirteen phyla were detected in the three groups of samples,which included 7 dominant phyla.29 dominant genera were detected in 184 genera.The abundance of Bacteroidetes _[G-6] and Peptostre ptococcaceae _[XI][G-4] had a positive correlation with the depth of the collection site of samples ( P microbial community structure on the root surface of patients with periodontitis.

  9. The Root-Associated Microbial Community of the World's Highest Growing Vascular Plants.

    Science.gov (United States)

    Angel, Roey; Conrad, Ralf; Dvorsky, Miroslav; Kopecky, Martin; Kotilínek, Milan; Hiiesalu, Inga; Schweingruber, Fritz; Doležal, Jiří

    2016-08-01

    Upward migration of plants to barren subnival areas is occurring worldwide due to raising ambient temperatures and glacial recession. In summer 2012, the presence of six vascular plants, growing in a single patch, was recorded at an unprecedented elevation of 6150 m.a.s.l. close to the summit of Mount Shukule II in the Western Himalayas (Ladakh, India). Whilst showing multiple signs of stress, all plants have managed to establish stable growth and persist for several years. To learn about the role of microbes in the process of plant upward migration, we analysed the root-associated microbial community of the plants (three individuals from each) using microscopy and tagged amplicon sequencing. No mycorrhizae were found on the roots, implying they are of little importance to the establishment and early growth of the plants. However, all roots were associated with a complex bacterial community, with richness and diversity estimates similar or even higher than the surrounding bare soil. Both soil and root-associated communities were dominated by members of the orders Sphingomonadales and Sphingobacteriales, which are typical for hot desert soils, but were different from communities of temperate subnival soils and typical rhizosphere communities. Despite taxonomic similarity on the order level, the plants harboured a unique set of highly dominant operational taxonomic units which were not found in the bare soil. These bacteria have been likely transported with the dispersing seeds and became part of the root-associated community following germination. The results indicate that developing soils act not only as a source of inoculation to plant roots but also possibly as a sink for plant-associated bacteria.

  10. Crop-associated virus reduces the rooting depth of non-crop perennial native grass more than non-crop-associated virus with known viral suppressor of RNA silencing (VSR).

    Science.gov (United States)

    Malmstrom, Carolyn M; Bigelow, Patrick; Trębicki, Piotr; Busch, Anna K; Friel, Colleen; Cole, Ellen; Abdel-Azim, Heba; Phillippo, Colin; Alexander, Helen M

    2017-09-15

    stunted annual Avena sativa L. (oats). These findings suggest that some of the diversity in grass-infecting Luteoviridae reflects viral capacity to modulate defenses in different host types. Intriguingly, while all virus treatments also reduced root production in both host species, only crop-associated BYDV-PAV (or co-infection) reduced rooting depths. Such root effects may increase host susceptibility to drought, and indicate that BYDV-PAV pathogenicity is determined by something other than a P0 VSR. These findings contribute to growing evidence that pathogenic crop-associated viruses may harm native species as well as crops. Critical next questions include the extent to which crop-associated selection pressures drive viral pathogenesis. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Feasibility of Invasive Grass Detection in a Desertscrub Community Using Hyperspectral Field Measurements and Landsat TM Imagery

    OpenAIRE

    Olsson, Aaryn D.; Leeuwen, Willem J.D. van; Marsh, Stuart E.

    2011-01-01

    Invasive species’ phenologies often contrast with those of native species, representing opportunities for detection of invasive species with multi-temporal remote sensing. Detection is especially critical for ecosystem-transforming species that facilitate changes in disturbance regimes. The African C4 grass, Pennisetum ciliare, is transforming ecosystems on three continents and a number of neotropical islands by introducing a grass-fire cycle. However, previous attempts at discriminating P. c...

  12. Linking fungal communities in roots, rhizosphere, and soil to the health status of Pisum sativum

    DEFF Research Database (Denmark)

    Xu, Lihui; Ravnskov, Sabine; Larsen, John

    2012-01-01

    the three fields identified a number of OTUs that were more abundant in healthy roots. Pathogens such as Fusarium oxysporum were abundant in diseased roots in some fields. Patterns of disease and causal agents of root rot were different among the three fields, which were also reflected in fungal communities...

  13. Different bacterial communities associated with the roots and bulk sediment of the seagrass Zostera marina

    DEFF Research Database (Denmark)

    Jensen, Sheila Ingemann; Kühl, Michael; Priemé, Anders

    2007-01-01

    to Epsilonproteobacteria showed a relative mean distribution of between 5% and 11% in the root-associated communities of the youngest root bundle, in contrast to the bulk-sediment where this TRF only contributed Actinobacteria and Gammaproteobacteria also seemed important first root...

  14. Community composition and activity of anaerobic ammonium oxidation bacteria in the rhizosphere of salt-marsh grass Spartina alterniflora.

    Science.gov (United States)

    Zheng, Yanling; Hou, Lijun; Liu, Min; Yin, Guoyu; Gao, Juan; Jiang, Xiaofen; Lin, Xianbiao; Li, Xiaofei; Yu, Chendi; Wang, Rong

    2016-09-01

    Anaerobic ammonium oxidation (anammox) as an important nitrogen removal pathway has been investigated in intertidal marshes. However, the rhizosphere-driven anammox process in these ecosystems is largely overlooked so far. In this study, the community dynamics and activities of anammox bacteria in the rhizosphere and non-rhizosphere sediments of salt-marsh grass Spartina alterniflora (a widely distributed plant in estuaries and intertidal ecosystems) were investigated using clone library analysis, quantitative PCR assay, and isotope-tracing technique. Phylogenetic analysis showed that anammox bacterial diversity was higher in the non-rhizosphere sediments (Scalindua and Kuenenia) compared with the rhizosphere zone (only Scalindua genus). Higher abundance of anammox bacteria was detected in the rhizosphere (6.46 × 10(6)-1.56 × 10(7) copies g(-1)), which was about 1.5-fold higher in comparison with that in the non-rhizosphere zone (4.22 × 10(6)-1.12 × 10(7) copies g(-1)). Nitrogen isotope-tracing experiments indicated that the anammox process in the rhizosphere contributed to 12-14 % N2 generation with rates of 0.43-1.58 nmol N g(-1) h(-1), while anammox activity in the non-rhizosphere zone contributed to only 4-7 % N2 production with significantly lower activities (0.28-0.83 nmol N g(-1) h(-1)). Overall, we propose that the rhizosphere microenvironment in intertidal marshes might provide a favorable niche for anammox bacteria and thus plays an important role in nitrogen cycling.

  15. Comparison of communities of arbuscular mycorrhizal fungi in roots of two Viola species

    DEFF Research Database (Denmark)

    Opik, M; Moora, Mari; Liira, Jaan

    2006-01-01

    The composition of arbuscular mycorrhizal (AM) fungal communities in roots of rare Viola elatior and common V. mirabilis was investigated using PCR with primers specific for Glomus and common was investigated using PCR with primers specific for group A, followed by single-stranded conformation...

  16. Rice root-associated bacteria: insights into community structures across 10 cultivars

    NARCIS (Netherlands)

    Hardoim, P.R.; Andreote, F.D.; Reinhold-Hurek, B.; Sessitsch, A.; Overbeek, van L.S.; Elsas, van J.D.

    2011-01-01

    In this study, the effects of plant genotype, soil type and nutrient use efficiency on the composition of different bacterial communities associated with rice roots were investigated. Thus, total bacteria, Alpha- and Betaproteobacteria, Pseudomonas and Actinobacteria were studied using PCR, followed

  17. Rice root-associated bacteria : insights into community structures across 10 cultivars

    NARCIS (Netherlands)

    Hardoim, P. R.; Andreote, F. D.; Reinhold-Hurek, B.; Sessitsch, A.; van Overbeek, L. S.; van Elsas, J. D.

    In this study, the effects of plant genotype, soil type and nutrient use efficiency on the composition of different bacterial communities associated with rice roots were investigated. Thus, total bacteria, Alpha- and Betaproteobacteria, Pseudomonas and Actinobacteria were studied using PCR, followed

  18. Nonlegumes, legumes, and root nodules harbor different arbuscular mycorrhizal fungal communities.

    NARCIS (Netherlands)

    Scheublin, T.R.; Ridgway, K.P.; Young, J.P.W.; van der Heijden, M.G.A.

    2004-01-01

    Legumes are an important plant functional group since they can form a tripartite symbiosis with nitrogen-fixing Rhizobium bacteria and phosphorus-acquiring arbuscular mycorrhizal fungi (AMF). However, not much is known about AMF community composition in legumes and their root nodules. In this study,

  19. Metagenomic insights into communities, functions of endophytes, and their associates with infection by root-knot nematode, Meloidogyne incognita, in tomato roots.

    Science.gov (United States)

    Tian, Bao-Yu; Cao, Yi; Zhang, Ke-Qin

    2015-11-25

    Endophytes are known to play important roles in plant's health and productivity. In this study, we investigated the root microbiome of tomato in association with infection by root knot nematodes. Our objectives were to observe the effects and response of the bacterial endophytes before nematode attacks and to reveal the functional attributes of microbes in plant health and nematode pathogenesis. Community analysis of root-associated microbiomes in healthy and nematode-infected tomatoes indicated that nematode infections were associated with variation and differentiation of the endophyte and rhizosphere bacterial populations in plant roots. The community of the resident endophytes in tomato root was significantly affected by nemato-pathogenesis. Remarkably, some bacterial groups in the nematode feeding structure, the root gall, were specifically enriched, suggesting an association with nematode pathogenesis. Function-based metagenomic analysis indicated that the enriched bacterial populations in root gall harbored abundant genes related to degradation of plant polysaccharides, carbohydrate and protein metabolism, and biological nitrogen fixation. Our data indicated that some of the previously assumed beneficial endophytes or bacterial associates with nematode might be involved in nematode infections of the tomato roots.

  20. Effect of an Invasive Grass on Ambient Rates of Decomposition and Microbial Community Structure: A Search for Causality

    Science.gov (United States)

    In sutu decomposition of above and below ground plant biomass of the native grass species Andropogon glmoeratus (Walt.) B.S.P and exotic Imperata cylindrica (L.) Beauv. (cogongrass) was investigated using litter bags over the course of a 12 month period. The above and below ground biomass of the inv...

  1. Wild plant species growing closely connected in a subalpine meadow host distinct root-associated bacterial communities

    Directory of Open Access Journals (Sweden)

    Kristin Aleklett

    2015-02-01

    Full Text Available Plant roots are known to harbor large and diverse communities of bacteria. It has been suggested that plant identity can structure these root-associated communities, but few studies have specifically assessed how the composition of root microbiota varies within and between plant species growing under natural conditions. We assessed the community composition of endophytic and epiphytic bacteria through high throughput sequencing using 16S rDNA derived from root tissues collected from a population of a wild, clonal plant (Orange hawkweed–Pilosella aurantiaca as well as two neighboring plant species (Oxeye daisy–Leucanthemum vulgare and Alsike clover–Trifolium hybridum. Our first goal was to determine if plant species growing in close proximity, under similar environmental conditions, still hosted unique root microbiota. Our results showed that plants of different species host distinct bacterial communities in their roots. In terms of community composition, Betaproteobacteria (especially the family Oxalobacteraceae were found to dominate in the root microbiota of L. vulgare and T. hybridum samples, whereas the root microbiota of P. aurantiaca had a more heterogeneous distribution of bacterial abundances where Gammaproteobacteria and Acidobacteria occupied a larger portion of the community. We also explored the extent of individual variance within each plant species investigated, and found that in the plant species thought to have the least genetic variance among individuals (P. aurantiaca still hosted just as diverse microbial communities. Whether all plant species host their own distinct root microbiota and plants more closely related to each other share more similar bacterial communities still remains to be fully explored, but among the plants examined in this experiment there was no trend that the two species belonging to the same family shared more similarities in terms of bacterial community composition.

  2. Selective progressive response of soil microbial community to wild oat roots

    Energy Technology Data Exchange (ETDEWEB)

    DeAngelis, K.M.; Brodie, E.L.; DeSantis, T.Z.; Andersen, G.L.; Lindow, S.E.; Firestone, M.K.

    2008-10-01

    Roots moving through soil enact physical and chemical changes that differentiate rhizosphere from bulk soil, and the effects of these changes on soil microorganisms have long been a topic of interest. Use of a high-density 16S rRNA microarray (PhyloChip) for bacterial and archaeal community analysis has allowed definition of the populations that respond to the root within the complex grassland soil community; this research accompanies previously reported compositional changes, including increases in chitinase and protease specific activity, cell numbers and quorum sensing signal. PhyloChip results showed a significant change in 7% of the total rhizosphere microbial community (147 of 1917 taxa); the 7% response value was confirmed by16S rRNA T-RFLP analysis. This PhyloChip-defined dynamic subset was comprised of taxa in 17 of the 44 phyla detected in all soil samples. Expected rhizosphere-competent phyla, such as Proteobacteria and Firmicutes, were well represented, as were less-well-documented rhizosphere colonizers including Actinobacteria, Verrucomicrobia and Nitrospira. Richness of Bacteroidetes and Actinobacteria decreased in soil near the root tip compared to bulk soil, but then increased in older root zones. Quantitative PCR revealed {beta}-Proteobacteria and Actinobacteria present at about 10{sup 8} copies of 16S rRNA genes g{sup -1} soil, with Nitrospira having about 10{sup 5} copies g{sup -1} soil. This report demonstrates that changes in a relatively small subset of the soil microbial community are sufficient to produce substantial changes in function in progressively more mature rhizosphere zones.

  3. Multiscale patterns and drivers of arbuscular mycorrhizal fungal communities in the roots and root-associated soil of a wild perennial herb.

    Science.gov (United States)

    Rasmussen, Pil U; Hugerth, Luisa W; Blanchet, F Guillaume; Andersson, Anders F; Lindahl, Björn D; Tack, Ayco J M

    2018-03-24

    Arbuscular mycorrhizal (AM) fungi form diverse communities and are known to influence above-ground community dynamics and biodiversity. However, the multiscale patterns and drivers of AM fungal composition and diversity are still poorly understood. We sequenced DNA markers from roots and root-associated soil from Plantago lanceolata plants collected across multiple spatial scales to allow comparison of AM fungal communities among neighbouring plants, plant subpopulations, nearby plant populations, and regions. We also measured soil nutrients, temperature, humidity, and community composition of neighbouring plants and nonAM root-associated fungi. AM fungal communities were already highly dissimilar among neighbouring plants (c. 30 cm apart), albeit with a high variation in the degree of similarity at this small spatial scale. AM fungal communities were increasingly, and more consistently, dissimilar at larger spatial scales. Spatial structure and environmental drivers explained a similar percentage of the variation, from 7% to 25%. A large fraction of the variation remained unexplained, which may be a result of unmeasured environmental variables, species interactions and stochastic processes. We conclude that AM fungal communities are highly variable among nearby plants. AM fungi may therefore play a major role in maintaining small-scale variation in community dynamics and biodiversity. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

  4. Effect of Elodea nuttallii roots on bacterial communities and MMHg proportion in a Hg polluted sediment.

    Science.gov (United States)

    Regier, Nicole; Frey, Beat; Converse, Brandon; Roden, Eric; Grosse-Honebrink, Alexander; Bravo, Andrea Garcia; Cosio, Claudia

    2012-01-01

    The objective of this study was to assess the effect of a rooted macrophyte Elodea nuttallii on rhizosphere bacterial communities in Hg contaminated sediments. Specimens of E. nuttallii were exposed to sediments from the Hg contaminated Babeni reservoir (Olt River, Romania) in our microcosm. Plants were allowed to grow for two months until they occupied the entirety of the sediments. Total Hg and MMHg were analysed in sediments where an increased MMHg percentage of the total Hg in pore water of rhizosphere sediments was found. E. nuttallii roots also significantly changed the bacterial community structure in rhizosphere sediments compared to bulk sediments. Deltaproteobacteria dominated the rhizosphere bacterial community where members of Geobacteraceae within the Desulfuromonadales and Desulfobacteraceae were identified. Two bacterial operational taxonomic units (OTUs) which were phylogenetically related to sulfate-reducing bacteria (SRB) became abundant in the rhizosphere. We suggest that these phylotypes could be potentially methylating bacteria and might be responsible for the higher MMHg percentage of the total Hg in rhizosphere sediments. However, SRB were not significantly favoured in rhizosphere sediments as shown by qPCR. Our findings support the hypothesis that rooted macrophytes created a microenvironment favorable for Hg methylation. The presence of E. nuttallii in Hg contaminated sediments should therefore not be overlooked.

  5. Effect of Elodea nuttallii roots on bacterial communities and MMHg proportion in a Hg polluted sediment.

    Directory of Open Access Journals (Sweden)

    Nicole Regier

    Full Text Available The objective of this study was to assess the effect of a rooted macrophyte Elodea nuttallii on rhizosphere bacterial communities in Hg contaminated sediments. Specimens of E. nuttallii were exposed to sediments from the Hg contaminated Babeni reservoir (Olt River, Romania in our microcosm. Plants were allowed to grow for two months until they occupied the entirety of the sediments. Total Hg and MMHg were analysed in sediments where an increased MMHg percentage of the total Hg in pore water of rhizosphere sediments was found. E. nuttallii roots also significantly changed the bacterial community structure in rhizosphere sediments compared to bulk sediments. Deltaproteobacteria dominated the rhizosphere bacterial community where members of Geobacteraceae within the Desulfuromonadales and Desulfobacteraceae were identified. Two bacterial operational taxonomic units (OTUs which were phylogenetically related to sulfate-reducing bacteria (SRB became abundant in the rhizosphere. We suggest that these phylotypes could be potentially methylating bacteria and might be responsible for the higher MMHg percentage of the total Hg in rhizosphere sediments. However, SRB were not significantly favoured in rhizosphere sediments as shown by qPCR. Our findings support the hypothesis that rooted macrophytes created a microenvironment favorable for Hg methylation. The presence of E. nuttallii in Hg contaminated sediments should therefore not be overlooked.

  6. Flooding greatly affects the diversity of arbuscular mycorrhizal fungi communities in the roots of wetland plants.

    Directory of Open Access Journals (Sweden)

    Yutao Wang

    Full Text Available The communities of arbuscular mycorrhizal fungi (AMF colonizing the roots of three mangrove species were characterized along a tidal gradient in a mangrove swamp. A fragment, designated SSU-ITS-LSU, including part of the small subunit (SSU, the entire internal transcribed spacer (ITS and part of the large subunit (LSU of rDNA from samples of AMF-colonized roots was amplified, cloned and sequenced using AMF-specific primers. Similar levels of AMF diversity to those observed in terrestrial ecosystems were detected in the roots, indicating that the communities of AMF in wetland ecosystems are not necessarily low in diversity. In total, 761 Glomeromycota sequences were obtained, which grouped, according to phylogenetic analysis using the SSU-ITS-LSU fragment, into 23 phylotypes, 22 of which belonged to Glomeraceae and one to Acaulosporaceae. The results indicate that flooding plays an important role in AMF diversity, and its effects appear to depend on the degree (duration of flooding. Both host species and tide level affected community structure of AMF, indicating the presence of habitat and host species preferences.

  7. Limited Effects of Variable-Retention Harvesting on Fungal Communities Decomposing Fine Roots in Coastal Temperate Rainforests.

    Science.gov (United States)

    Philpott, Timothy J; Barker, Jason S; Prescott, Cindy E; Grayston, Sue J

    2018-02-01

    Fine root litter is the principal source of carbon stored in forest soils and a dominant source of carbon for fungal decomposers. Differences in decomposer capacity between fungal species may be important determinants of fine-root decomposition rates. Variable-retention harvesting (VRH) provides refuge for ectomycorrhizal fungi, but its influence on fine-root decomposers is unknown, as are the effects of functional shifts in these fungal communities on carbon cycling. We compared fungal communities decomposing fine roots (in litter bags) under VRH, clear-cut, and uncut stands at two sites (6 and 13 years postharvest) and two decay stages (43 days and 1 year after burial) in Douglas fir forests in coastal British Columbia, Canada. Fungal species and guilds were identified from decomposed fine roots using high-throughput sequencing. Variable retention had short-term effects on β-diversity; harvest treatment modified the fungal community composition at the 6-year-postharvest site, but not at the 13-year-postharvest site. Ericoid and ectomycorrhizal guilds were not more abundant under VRH, but stand age significantly structured species composition. Guild composition varied by decay stage, with ruderal species later replaced by saprotrophs and ectomycorrhizae. Ectomycorrhizal abundance on decomposing fine roots may partially explain why fine roots typically decompose more slowly than surface litter. Our results indicate that stand age structures fine-root decomposers but that decay stage is more important in structuring the fungal community than shifts caused by harvesting. The rapid postharvest recovery of fungal communities decomposing fine roots suggests resiliency within this community, at least in these young regenerating stands in coastal British Columbia. IMPORTANCE Globally, fine roots are a dominant source of carbon in forest soils, yet the fungi that decompose this material and that drive the sequestration or respiration of this carbon remain largely

  8. Feasibility of Invasive Grass Detection in a Desertscrub Community Using Hyperspectral Field Measurements and Landsat TM Imagery

    Directory of Open Access Journals (Sweden)

    Stuart E. Marsh

    2011-10-01

    Full Text Available Invasive species’ phenologies often contrast with those of native species, representing opportunities for detection of invasive species with multi-temporal remote sensing. Detection is especially critical for ecosystem-transforming species that facilitate changes in disturbance regimes. The African C4 grass, Pennisetum ciliare, is transforming ecosystems on three continents and a number of neotropical islands by introducing a grass-fire cycle. However, previous attempts at discriminating P. ciliare in North America using multi-spectral imagery have been unsuccessful. In this paper, we integrate field measurements of hyperspectral plant species signatures and canopy cover with multi-temporal spectral analysis to identify opportunities for detection using moderate-resolution multi-spectral imagery. By applying these results to Landsat TM imagery, we show that multi-spectral discrimination of P. ciliare in heterogeneous mixed desert scrub is feasible, but only at high abundance levels that may have limited value to land managers seeking to control invasion. Much higher discriminability is possible with hyperspectral shortwave infrared imagery because of differences in non-photosynthetic vegetation in uninvaded and invaded landscapes during dormant seasons but these spectra are unavailable in multispectral sensors. Therefore, we recommend hyperspectral imagery for distinguishing invasive grass-dominated landscapes from uninvaded desert scrub.

  9. Quantifying the contribution of root systems to community and individual drought resilience in the Amazon rainforest

    Science.gov (United States)

    Agee, E.; Ivanov, V. Y.; Oliveira, R. S.; Brum, M., Jr.; Saleska, S. R.; Bisht, G.; Prohaska, N.; Taylor, T.; Oliveira Junior, R. C.; Restrepo-Coupe, N.

    2017-12-01

    The increased intensity and severity of droughts within the Amazon Basin region has emphasized the question of vulnerability and resilience of tropical forests to water limitation. During the recent 2015-2016 drought caused by the anomalous El Nino episode, we monitored a large, diverse sample of trees within the Tapajos National Forest, Brazil, in the footprint of the K67 eddy covariance tower. The observed trees exhibited differential responses in terms of stem water potential and sap flow among species: their regulation of ecophysiological strategies varied from very conservative (`isohydric') behavior, to much less restrained, atmosphere-controlled (`anisohydric') type of response. While much attention has been paid to forest canopies, it remains unclear how the regulation of individual tree root system and root spatial interactions contribute to the emergent individual behavior and the ecosystem-scale characterization of drought resilience. Given the inherent difficulty in monitoring below-ground phenomena, physically-based models are valuable for examining different strategies and properties to reduce the uncertainty of characterization. We use a modified version of the highly parallel DOE PFLOTRAN model to simulate the three-dimensional variably saturated flows and root water uptake for over one thousand individuals within a two-hectare area. Root morphology and intrinsic hydraulic properties are assigned based on statistical distributions developed for tropical trees, which account for the broad spectrum of hydraulic strategies in biodiverse environments. The results demonstrate the dynamic nature of active zone of root water uptake based on local soil water potential gradients. The degree of the corresponding shifts in uptake and root collar potential depend not only on assigned hydraulic properties but also on spatial orientation and size relative to community members. This response highlights the importance of not only tree individual hydraulic traits

  10. Grass genomes

    OpenAIRE

    Bennetzen, Jeffrey L.; SanMiguel, Phillip; Chen, Mingsheng; Tikhonov, Alexander; Francki, Michael; Avramova, Zoya

    1998-01-01

    For the most part, studies of grass genome structure have been limited to the generation of whole-genome genetic maps or the fine structure and sequence analysis of single genes or gene clusters. We have investigated large contiguous segments of the genomes of maize, sorghum, and rice, primarily focusing on intergenic spaces. Our data indicate that much (>50%) of the maize genome is composed of interspersed repetitive DNAs, primarily nested retrotransposons that in...

  11. Concentration of petroleum-hydrocarbon contamination shapes fungal endophytic community structure in plant roots

    Directory of Open Access Journals (Sweden)

    Guillaume eBourdel

    2016-05-01

    Full Text Available Plant-root inhabiting fungi are a universal phenomenon found in all ecosystems where plants are able to grow, even in harsh environments. Interactions between fungi and plant roots can vary widely from mutualism to parasitism depending on many parameters. The role of fungal endophytes in phytoremediation of polluted sites, and characterization of the endophytic diversity and community assemblages in contaminated areas remain largely unexplored. In this study, we investigated the composition of endophytic fungal communities in the roots of two plant species growing spontaneously in petroleum-contaminated sedimentation basins of a former petro-chemical plant. The three adjacent basins showed a highly heterogeneous patterns of pollutant concentrations. We combined a culture-based isolation approach with the pyrosequencing of fungal ITS ribosomal DNA. We selected two species, Eleocharis erythropoda Steud. and Populus balsamifera L., and sampled three individuals of each species from each of three adjacent basins, each with a different concentration of petroleum hydrocarbons. We found that contamination level significantly shaped endophytic fungal diversity and community composition in E. erythropoda, with only 9.9% of these fungal Operational Taxonomic Units (OTUs retrieved in all three basins. However, fungal community structure associated with P. balsamifera remained unaffected by the contamination level with 28.2% of fungal OTUs shared among all three basins. This could be explained by the smaller differences of pollutant concentrations in the soil around our set of P. balsamifera sampless compared to that around our set of E. erythropoda samples. Our culture-based approach allowed isolation of 11 and 30 fungal endophytic species from surface-sterilized roots of E. erythropoda and P. balsamifera, respectively. These isolates were ribotyped using ITS, and all were found in pyrosequensing datasets. Our results demonstrate that extreme levels of

  12. Metagenome analysis of the root endophytic microbial community of Indian rice (O. sativa L.

    Directory of Open Access Journals (Sweden)

    Subhadipa Sengupta

    2017-06-01

    Full Text Available This study reports the root endophytic microbial community profile in rice (Oryza sativa L., the largest food crop of Asia, using 16S rRNA gene amplicon sequencing. Metagenome of OS01 and OS04 consisted of 11,17,900 sequences with 300 Mbp size and average 55.6% G + C content. Data of this study are available at NCBI Bioproject (PRJNA360379. The taxonomic analysis of 843 OTU's showed that the sequences belonged to four major phyla revealing dominance of Proteobacteria, Firmicutes, Cyanobacteria and Actinobacteria. Results reveal the dominance of Bacillus as major endophytic genera in rice roots, probably playing a key role in Nitrogen fixation.

  13. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities.

    Science.gov (United States)

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2017-01-01

    Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species ( Solidago canadensis, Populus balsamifera , and Lycopus europaeus ) growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF) spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP) concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate or degrade the

  14. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities

    Directory of Open Access Journals (Sweden)

    Bachir Iffis

    2017-08-01

    Full Text Available Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species (Solidago canadensis, Populus balsamifera, and Lycopus europaeus growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate

  15. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities

    Science.gov (United States)

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2017-01-01

    Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species (Solidago canadensis, Populus balsamifera, and Lycopus europaeus) growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF) spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP) concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate or degrade the

  16. Effects of cowpea (Vigna unguiculata) root mucilage on microbial community response and capacity for phenanthrene remediation.

    Science.gov (United States)

    Sun, Ran; Belcher, Richard W; Liang, Jianqiang; Wang, Li; Thater, Brian; Crowley, David E; Wei, Gehong

    2015-07-01

    Biodegradation of polycyclic aromatic hydrocarbons (PAHs) is normally limited by their low solubility and poor bioavailability. Prior research suggests that biosurfactants are synthesized as intermediates during the production of mucilage at the root tip. To date the effects of mucilage on PAH degradation and microbial community response have not been directly examined. To address this question, our research compared 3 cowpea breeding lines (Vigna unguiculata) that differed in mucilage production for their effects on phenanthrene (PHE) degradation in soil. The High Performance Liquid Chromatography results indicated that the highest PHE degradation rate was achieved in soils planted with mucilage producing cowpea line C1, inoculated with Bradyrhizobium, leading to 91.6% PHE disappearance in 5 weeks. In root printing tests, strings treated with mucilage and bacteria produced larger clearing zones than those produced on mucilage treated strings with no bacteria or bacteria inoculated strings. Experiments with 14C-PHE and purified mucilage in soil slurry confirmed that the root mucilage significantly enhanced PHE mineralization (82.7%), which is 12% more than the control treatment without mucilage. The profiles of the PHE degraders generated by Denaturing gradient gel electrophoresis suggested that cowpea C1, producing a high amount of root mucilage, selectively enriched the PHE degrading bacteria population in rhizosphere. These findings indicate that root mucilage may play a significant role in enhancing PHE degradation and suggests that differences in mucilage production may be an important criterion for selection of the best plant species for use in phytoremediation of PAH contaminated soils. Copyright © 2015. Published by Elsevier B.V.

  17. Common mycelial networks impact competition in an invasive grass.

    Science.gov (United States)

    Workman, Rachael E; Cruzan, Mitchell B

    2016-06-01

    Mycorrhizal hyphal complexes can connect multiple host plants to form common mycelial networks (CMNs) that may affect plant competitive outcomes and community composition through differential resource allocation. The impacts of CMN interactions on invasive plants are not well understood and could be crucial to the understanding of invasive plant establishment and success. We grew the invasive grass Brachypodium sylvaticum in intra- and interspecific pairings with native grass Bromus vulgaris in a greenhouse and controlled for the effects of CMN and root interactions by manipulating the belowground separation between competitors. Comparison of plant growth in pots that allowed CMN interactions and excluded root competition and vice versa, or both, allowed us to delineate the effects of network formation and root competition on invasive plant establishment and performance. Brachypodium sylvaticum grown in pots allowing for only hyphal interactions, but no root competition, displayed superior growth compared with conspecifics in other treatments. Invasive performance was poorest when pairs were not separated by a barrier. Shoot nitrogen content in B. sylvaticum was higher in mycorrhizal plants only when connections were allowed between competitors. Our results indicate that the presence of CMN networks can have positive effects on B. sylvaticum establishment and nutrient status, which may affect plant competition and invasion success. © 2016 Botanical Society of America.

  18. Degradation of Root Community Traits as Indicator for Transformation of Tropical Lowland Rain Forests into Oil Palm and Rubber Plantations.

    Science.gov (United States)

    Sahner, Josephine; Budi, Sri Wilarso; Barus, Henry; Edy, Nur; Meyer, Marike; Corre, Marife D; Polle, Andrea

    2015-01-01

    Conversion of tropical forests into intensely managed plantations is a threat to ecosystem functions. On Sumatra, Indonesia, oil palm (Elaeis guineensis) plantations are rapidly expanding, displacing rain forests and extensively used rubber (Hevea brasiliensis) agro-forests. Here, we tested the influence of land use systems on root traits including chemical traits (carbon, nitrogen, mineral nutrients, potentially toxic elements [aluminium, iron] and performance traits (root mass, vitality, mycorrhizal colonization). Traits were measured as root community-weighed traits (RCWTs) in lowland rain forests, in rubber agro-forests mixed with rain forest trees, in rubber and oil palm plantations in two landscapes (Bukit Duabelas and Harapan, Sumatra). We hypothesized that RCWTs vary with land use system indicating increasing transformation intensity and loss of ecosystem functions. The main factors found to be related to increasing transformation intensity were declining root vitality and root sulfur, nitrogen, carbon, manganese concentrations and increasing root aluminium and iron concentrations as well as increasing spore densities of arbuscular mycorrhizas. Mycorrhizal abundance was high for arbuscular and low for ectomycorrhizas and unrelated to changes in RCWTs. The decline in RCWTs showed significant correlations with soil nitrogen, soil pH and litter carbon. Thus, our study uncovered a relationship between deteriorating root community traits and loss of ecosystem functionality and showed that increasing transformation intensity resulted in decreasing root nutrition and health. Based on these results we suggest that land management that improves root vitality may enhance the ecological functions of intense tropical production systems.

  19. Root phenotypic differences across a historical gradient of wheat genotypes alter soil rhizosphere communities and their impact on nitrogen cycling

    Science.gov (United States)

    Kallenbach, C.; Junaidi, D.; Fonte, S.; Byrne, P. F.; Wallenstein, M. D.

    2017-12-01

    Plants and soil microorganisms can exhibit coevolutionary relationships where, for example, in exchange for root carbon, rhizosphere microbes enhance plant fitness through improved plant nutrient availability. Organic agriculture relies heavily on these interactions to enhance crop nitrogen (N) availability. However, modern agriculture and breeding under high mineral N fertilization may have disrupted these interactions through alterations to belowground carbon inputs and associated impacts on the soil microbiome. As sustainability initiatives lead to a restoration of agricultural soil organic matter, modern crop cultivars may still be constrained by crop roots' ability to effectively support microbial-mediated N mineralization. We investigated how differences in root traits across a historical gradient of spring wheat genotypes influence the rhizosphere microbial community and effects on soil N and wheat yield. Five genotypes, representing wild (Wild), pre-Green Revolution (Old), and modern (Modern) wheat, were grown under greenhouse conditions in soils with and without compost to also compare genotype response to difference in native soil microbiomes and organic resource availability. We analyzed rhizosphere soils for microbial community composition, enzyme activities, inorganic N, and microbial biomass. Root length density, surface area, fine root volume and root:shoot ratio were higher in the Wild and Old genotype (Gypsum) compared to the two Modern genotypes (Psoil inorganic N, compared to Modern genotypes. However, under unamended soils, the microbial community and soil N were not affected by genotypes. We also relate how root traits and N cycling across genotypes correspond to microbial community composition. Our preliminary data suggest that the older wheat genotypes and their root traits are more effective at enhancing microbial N mineralization under organically managed soils. Thus, to optimize crop N availability from organic sources, breeding efforts

  20. Unexpectedly high beta-diversity of root-associated fungal communities in the Bolivian Andes

    DEFF Research Database (Denmark)

    Barnes, Christopher James; Maldonado Goyzueta, Carla Brenda; Frøslev, Tobias Guldberg

    2016-01-01

    in microbial diversity. Here we assess the genetic, taxonomic and functional diversity of root-associated fungi surrounding Cinchona calisaya calisaya trees, a typical element of the intermediate altitudes of the Bolivian Yungas. We determine the relative effects of edaphic properties, climate, and geography...... variation respectively. Surprisingly, altitude does not influence community formation, and there is limited evidence that climate (precipitation and temperature) play a role. Our results suggest that sampling should be performed over a wide geographical and environmental range in order to capture the full...

  1. Comparing soil organic carbon dynamics in perennial grasses and shrubs in a saline-alkaline arid region, northwestern China.

    Science.gov (United States)

    Zhou, Yong; Pei, Zhiqin; Su, Jiaqi; Zhang, Jingli; Zheng, Yuanrun; Ni, Jian; Xiao, Chunwang; Wang, Renzhong

    2012-01-01

    Although semi-arid and arid regions account for about 40% of terrestrial surface of the Earth and contain approximately 10% of the global soil organic carbon stock, our understanding of soil organic carbon dynamics in these regions is limited. A field experiment was conducted to compare soil organic carbon dynamics between a perennial grass community dominated by Cleistogenes squarrosa and an adjacent shrub community co-dominated by Reaumuria soongorica and Haloxylon ammodendron, two typical plant life forms in arid ecosystems of saline-alkaline arid regions in northwestern China during the growing season 2010. We found that both fine root biomass and necromass in two life forms varied greatly during the growing season. Annual fine root production in the perennial grasses was 45.6% significantly higher than in the shrubs, and fine root turnover rates were 2.52 and 2.17 yr(-1) for the perennial grasses and the shrubs, respectively. Floor mass was significantly higher in the perennial grasses than in the shrubs due to the decomposition rate of leaf litter in the perennial grasses was 61.8% lower than in the shrubs even though no significance was detected in litterfall production. Soil microbial biomass and activity demonstrated a strong seasonal variation with larger values in May and September and minimum values in the dry month of July. Observed higher soil organic carbon stocks in the perennial grasses (1.32 Kg C m(-2)) than in the shrubs (1.12 Kg C m(-2)) might be attributed to both greater inputs of poor quality litter that is relatively resistant to decay and the lower ability of microorganism to decompose these organic matter. Our results suggest that the perennial grasses might accumulate more soil organic carbon with time than the shrubs because of larger amounts of inputs from litter and slower return of carbon through decomposition.

  2. guinea grass

    African Journals Online (AJOL)

    SAM

    2014-05-07

    May 7, 2014 ... of metals in P. maximum tissues decreased in the order root > stem > foliage. ... effect clean up by phytoremediation is a function of the plant type and ... the spatial distribution of electrical conductivity (EC) may ... metals were measured weekly according to the method of Onianwa ..... Plant Cell Physiol.

  3. Common and distinguishing features of the bacterial and fungal communities in biological soil crusts and shrub root zone soils

    Science.gov (United States)

    Steven, Blaire; Gallegos-Graves, La Verne; Yeager, Chris; Belnap, Jayne; Kuske, Cheryl R.

    2013-01-01

    Soil microbial communities in dryland ecosystems play important roles as root associates of the widely spaced plants and as the dominant members of biological soil crusts (biocrusts) colonizing the plant interspaces. We employed rRNA gene sequencing (bacterial 16S/fungal large subunit) and shotgun metagenomic sequencing to compare the microbial communities inhabiting the root zones of the dominant shrub, Larrea tridentata (creosote bush), and the interspace biocrusts in a Mojave desert shrubland within the Nevada Free Air CO2 Enrichment (FACE) experiment. Most of the numerically abundant bacteria and fungi were present in both the biocrusts and root zones, although the proportional abundance of those members differed significantly between habitats. Biocrust bacteria were predominantly Cyanobacteria while root zones harbored significantly more Actinobacteria and Proteobacteria. Pezizomycetes fungi dominated the biocrusts while Dothideomycetes were highest in root zones. Functional gene abundances in metagenome sequence datasets reflected the taxonomic differences noted in the 16S rRNA datasets. For example, functional categories related to photosynthesis, circadian clock proteins, and heterocyst-associated genes were enriched in the biocrusts, where populations of Cyanobacteria were larger. Genes related to potassium metabolism were also more abundant in the biocrusts, suggesting differences in nutrient cycling between biocrusts and root zones. Finally, ten years of elevated atmospheric CO2 did not result in large shifts in taxonomic composition of the bacterial or fungal communities or the functional gene inventories in the shotgun metagenomes.

  4. Endophytic fungal communities associated with field-grown soybean roots and seeds in the Huang-Huai region of China

    Directory of Open Access Journals (Sweden)

    Hongjun Yang

    2018-04-01

    Full Text Available Plants depend on beneficial interactions between roots and fungal endophytes for growth, disease suppression, and stress tolerance. In this study, we characterized the endophytic fungal communities associated with the roots and corresponding seeds of soybeans grown in the Huang-Huai region of China. For the roots, we identified 105 and 50 genera by culture-independent and culture-dependent (CD methods, respectively, and isolated 136 fungal strains (20 genera from the CD samples. Compared with the 52 soybean endophytic fungal genera reported in other countries, 28 of the genera we found were reported, and 90 were newly discovered. Even though Fusarium was the most abundant genus of fungal endophyte in every sample, soybean root samples from three cities exhibited diverse endophytic fungal communities, and the results between samples of roots and seeds were also significantly different. Together, we identified the major endophytic fungal genera in soybean roots and seeds, and revealed that the diversity of soybean endophytic fungal communities was influenced by geographical effects and tissues. The results will facilitate a better understanding of soybean–endophytic fungi interaction systems and will assist in the screening and utilization of beneficial microorganisms to promote healthy of plants such as soybean.

  5. Acetogenic and Sulfate-Reducing Bacteria Inhabiting the Rhizoplane and Deep Cortex Cells of the Sea Grass Halodule wrightii†

    Science.gov (United States)

    Küsel, Kirsten; Pinkart, Holly C.; Drake, Harold L.; Devereux, Richard

    1999-01-01

    Recent declines in sea grass distribution underscore the importance of understanding microbial community structure-function relationships in sea grass rhizospheres that might affect the viability of these plants. Phospholipid fatty acid analyses showed that sulfate-reducing bacteria and clostridia were enriched in sediments colonized by the sea grasses Halodule wrightii and Thalassia testudinum compared to an adjacent unvegetated sediment. Most-probable-number analyses found that in contrast to butyrate-producing clostridia, acetogens and acetate-utilizing sulfate reducers were enriched by an order of magnitude in rhizosphere sediments. Although sea grass roots are oxygenated in the daytime, colorimetric root incubation studies demonstrated that acetogenic O-demethylation and sulfidogenic iron precipitation activities were tightly associated with washed, sediment-free H. wrightii roots. This suggests that the associated anaerobes are able to tolerate exposure to oxygen. To localize and quantify the anaerobic microbial colonization, root thin sections were hybridized with newly developed 33P-labeled probes that targeted (i) low-G+C-content gram-positive bacteria, (ii) cluster I species of clostridia, (iii) species of Acetobacterium, and (iv) species of Desulfovibrio. Microautoradiography revealed intercellular colonization of the roots by Acetobacterium and Desulfovibrio species. Acetogenic bacteria occurred mostly in the rhizoplane and outermost cortex cell layers, and high numbers of sulfate reducers were detected on all epidermal cells and inward, colonizing some 60% of the deepest cortex cells. Approximately 30% of epidermal cells were colonized by bacteria that hybridized with an archaeal probe, strongly suggesting the presence of methanogens. Obligate anaerobes within the roots might contribute to the vitality of sea grasses and other aquatic plants and to the biogeochemistry of the surrounding sediment. PMID:10543830

  6. Dramatic changes in ectomycorrhizal community composition, root tip abundance and mycelial production along a stand-scale nitrogen deposition gradient

    DEFF Research Database (Denmark)

    Kjøller, Rasmus; Nilsson, Lars Ola; Hansen, Karin

    2012-01-01

    • Nitrogen (N) availability is known to influence ectomycorrhizal fungal components, such as fungal community composition, biomass of root tips and production of mycelia, but effects have never been demonstrated within the same forest. • We measured concurrently the abundance of ectomycorrhizal...... root tips and the production of external mycelia, and explored the changes in the ectomycorrhizal community composition, across a stand-scale N deposition gradient (from 27 to 43 kg N ha¿¹ yr¿¹) at the edge of a spruce forest. The N status was affected along the gradient as shown by a range of N...... availability indices. • Ectomycorrhizal root tip abundance and mycelial production decreased five and 10-fold, respectively, with increasing N deposition. In addition, the ectomycorrhizal fungal community changed and the species richness decreased. The changes were correlated with the measured indices of N...

  7. “¡Somos Más Americanos!”: The music of Los Tigres del Norte as Grass Roots Activism

    OpenAIRE

    Rodriguez, Mariana

    2009-01-01

    The music of popular Mexican band Los Tigres del Norte illustrates a Mexican migrant and Chicano/a tradition of using popular music as an alternative way of narrating community life in the U.S.A., most notably the Mexican migrant, Chicana/o and Mexican-American experience of discrimination along ethnic, class, gender and cultural lines. The band grapples with the ways by which a dominant U.S. national discourse has historically subordinated Mexican migrant and Chicano/a communities. Through t...

  8. Reproduction and dispersal in an ant-associated root aphid community

    DEFF Research Database (Denmark)

    Ivens, A.B.F.; Kronauer, Daniel Jan Christoph; Pen, I.

    2012-01-01

    viscosity is high and winged aphids rare, consistent with infrequent horizontal transmission between ant host colonies. The absence of the primary host shrub (Pistacia) may explain the absence of sex in three of the studied species, but elm trees (Ulmus) that are primary hosts of the fourth species (T...... above ground, whereas dispersal constraints and dependence on ant-tending may differentially affect the costs and benefits of sex in subterranean aphids. Here, we studied reproductive mode and dispersal in a community of root aphids that are obligately associated with the ant Lasius flavus. We assessed...... the genetic population structure of four species (Geoica utricularia, Tetraneura ulmi, Forda marginata and Forda formicaria) in a Dutch population and found that all species reproduce predominantly if not exclusively asexually, so that populations consist of multiple clonal lineages. We show that population...

  9. Root uptake of 137Cs by natural and semi-natural grasses as a function of texture and moisture of soils

    International Nuclear Information System (INIS)

    Grytsyuk, N.; Arapis, G.; Davydchuk, V.

    2006-01-01

    This work studies the dependence of 137 Cs root uptake on the structure of landscape, especially on texture and moisture of soils, under natural conditions, on abandoned radiopolluted lands in Northern Ukraine. Researches were carried out on a wide range of landscape conditions, at various levels of 137 Cs contamination (from 20 up to 5000 kBq m -2 ), with different types of soils (approx. 20 soil varieties), which differ in texture, granulometric composition, degrees of gleyization and water regime, and anthropogenic transformation. The results showed that transfer factor (TF) values of 137 Cs differ 50 times for the natural grassy coenoses and 8 times for the semi-natural ones. The lowest 137 Cs TF values were measured in the herbages of dry meadows at automorphous loamy soils, while the highest were observed in wetland meadows at organic soils. Finally, the correlation between 137 Cs TF values and granulometric composition of soil was determined for both automorphic and hydromorphic mineral soils

  10. Presence of Trifolium repens promotes complementarity of water use and N facilitation in diverse grass mixtures

    Directory of Open Access Journals (Sweden)

    Pauline eHernandez

    2016-04-01

    Full Text Available Legume species promote productivity and increase the digestibility of herbage in grasslands. Considerable experimental data also indicate that communities with legumes produce more above-ground biomass than is expected from monocultures. While it has been attributed to N facilitation, evidence to identify the mechanisms involved is still lacking and the role of complementarity in soil water acquisition by vertical root differentiation remains unclear. We used a 20-month mesocosm experiment to investigate the effects of species richness (single species, two- and five-species mixtures and functional diversity (presence of the legume Trifolium repens on a set of traits related to light, N and water use and measured at community level. We found a positive effect of Trifolium presence and abundance on biomass production and complementarity effects in the two-species mixtures from the second year. In addition the community traits related to water and N acquisition and use (leaf area, N, water-use efficiency and deep root growth were higher in the presence of Trifolium. With a multiple regression approach, we showed that the traits related to water acquisition and use were with N the main determinants of biomass production and complementarity effects in diverse mixtures. At shallow soil layers, lower root mass of Trifolium and higher soil moisture should increase soil water availability for the associated grass species. Conversely at deep soil layer, higher root growth and lower soil moisture mirror soil resource use increase of mixtures. Altogether, these results highlight N facilitation but almost soil vertical differentiation and thus complementarity for water acquisition and use in mixtures with Trifolium. Contrary to grass-Trifolium mixtures, no significant over-yielding was measured for grass mixtures even those having complementary traits (short and shallow vs tall and deep. Thus, vertical complementarity for soil resources uptake in mixtures

  11. Presence of Trifolium repens Promotes Complementarity of Water Use and N Facilitation in Diverse Grass Mixtures.

    Science.gov (United States)

    Hernandez, Pauline; Picon-Cochard, Catherine

    2016-01-01

    Legume species promote productivity and increase the digestibility of herbage in grasslands. Considerable experimental data also indicate that communities with legumes produce more above-ground biomass than is expected from monocultures. While it has been attributed to N facilitation, evidence to identify the mechanisms involved is still lacking and the role of complementarity in soil water acquisition by vertical root differentiation remains unclear. We used a 20-months mesocosm experiment to investigate the effects of species richness (single species, two- and five-species mixtures) and functional diversity (presence of the legume Trifolium repens) on a set of traits related to light, N and water use and measured at community level. We found a positive effect of Trifolium presence and abundance on biomass production and complementarity effects in the two-species mixtures from the second year. In addition the community traits related to water and N acquisition and use (leaf area, N, water-use efficiency, and deep root growth) were higher in the presence of Trifolium. With a multiple regression approach, we showed that the traits related to water acquisition and use were with N the main determinants of biomass production and complementarity effects in diverse mixtures. At shallow soil layers, lower root mass of Trifolium and higher soil moisture should increase soil water availability for the associated grass species. Conversely at deep soil layer, higher root growth and lower soil moisture mirror soil resource use increase of mixtures. Altogether, these results highlight N facilitation but almost soil vertical differentiation and thus complementarity for water acquisition and use in mixtures with Trifolium. Contrary to grass-Trifolium mixtures, no significant over-yielding was measured for grass mixtures even those having complementary traits (short and shallow vs. tall and deep). Thus, vertical complementarity for soil resources uptake in mixtures was not only

  12. Oasis desert farming selects environment-specific date palm root endophytic communities and cultivable bacteria that promote resistance to drought

    KAUST Repository

    Cherif, Hanene; Marasco, Ramona; Rolli, Eleonora; Ferjani, Raoudha; Fusi, Marco; Soussi, Asma; Mapelli, Francesca; Blilou, Ikram; Borin, Sara; Boudabous, Abdellatif; Cherif, Ameur; Daffonchio, Daniele; Ouzari, Hadda

    2015-01-01

    Oases are desert-farming agro-ecosystems, where date palm (Phoenix dactyliferaL.) plays a keystone role in offsetting the effects of drought and maintaining a suitable microclimate for agriculture. At present, abundance, diversity and plant growth promotion (PGP) of date palm root-associated bacteria remain unknown. Considering the environmental pressure determined by the water scarcity in the desert environments, we hypothesized that bacteria associated with date palm roots improve plant resistance to drought. Here, the ecology of date palm root endophytes from oases in the Tunisian Sahara was studied with emphasis on their capacity to promote growth under drought. Endophytic communities segregated along a north-south gradient in correlation with geo-climatic parameters. Screening of 120 endophytes indicated that date palm roots select for bacteria with multiple PGP traits. Bacteria rapidly cross-colonized the root tissues of different species of plants, including the original Tunisian date palm cultivar, Saudi Arabian cultivars and Arabidopsis. Selected endophytes significantly increased the biomass of date palms exposed to repeated drought stress periods during a 9-month greenhouse experiment. Overall, results indicate that date palm roots shape endophytic communities that are capable to promote plant growth under drought conditions, thereby contributing an essential ecological service to the entire oasis ecosystem. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  13. Community structure of fish larvae in mangroves with different root types in Labuhan coastal area, Sepulu - Madura

    Science.gov (United States)

    Muzaki, Farid Kamal; Giffari, Aninditha; Saptarini, Dian

    2017-06-01

    Mangrove root complexity and shading are well known to give positive correlation for both juveniles and adult fishes. However, it is remain unclear whether that complexity would affect the community of fish larvae (ichthyoplankton). This study aimed to address the question, especially in mangrove area in coastal area of Sepulu, Madura which projected as a mangrove protection area. Sampling periods were from March to May, 2016. The samples of fish larvae were collected by plankton net (mesh-size 0.150 and 0.265 mm) from six different locations representing different root types (stilt root, pneumatophore, combination of stilt root-pneumatophore and unvegetated area). As the results, 6 families were identified, namely Gobiidae, Blennidae, Pomacentridae, Carangidae, Engraulidae and Ambassidae, respectively. Gobiidae seems to be the most abundant and widely dispersed in the area. Results of two-way AnovadanTukey HSD (both at p=0.05) indicate that there were significant difference in the larval abundance regarding locations, sampling periods and interaction of both factors. As for number of taxa, significant difference occurred only from factors of locations and sampling periods, but not for interaction of both factors. Highest larval abundance and number of taxa occurred in Rhizophoraspp (with stilt root), indicating that root complexity would affect the community of fish larvae. Ordination by canonical analysis shows that different taxa of the fish larvae are tend to be distributed on different locations.

  14. Oasis desert farming selects environment-specific date palm root endophytic communities and cultivable bacteria that promote resistance to drought

    KAUST Repository

    Cherif, Hanene

    2015-07-21

    Oases are desert-farming agro-ecosystems, where date palm (Phoenix dactyliferaL.) plays a keystone role in offsetting the effects of drought and maintaining a suitable microclimate for agriculture. At present, abundance, diversity and plant growth promotion (PGP) of date palm root-associated bacteria remain unknown. Considering the environmental pressure determined by the water scarcity in the desert environments, we hypothesized that bacteria associated with date palm roots improve plant resistance to drought. Here, the ecology of date palm root endophytes from oases in the Tunisian Sahara was studied with emphasis on their capacity to promote growth under drought. Endophytic communities segregated along a north-south gradient in correlation with geo-climatic parameters. Screening of 120 endophytes indicated that date palm roots select for bacteria with multiple PGP traits. Bacteria rapidly cross-colonized the root tissues of different species of plants, including the original Tunisian date palm cultivar, Saudi Arabian cultivars and Arabidopsis. Selected endophytes significantly increased the biomass of date palms exposed to repeated drought stress periods during a 9-month greenhouse experiment. Overall, results indicate that date palm roots shape endophytic communities that are capable to promote plant growth under drought conditions, thereby contributing an essential ecological service to the entire oasis ecosystem. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Effectiveness of DIAGNOdent in Detecting Root Caries Without Dental Scaling Among Community-dwelling Elderly.

    Science.gov (United States)

    Zhang, Wen; McGrath, Colman; Lo, Edward C M

    The purpose of this clinical research was to analyze the effectiveness of DIAGNOdent in detecting root caries without dental scaling. The status of 750 exposed, unfilled root surfaces was assessed by visual-tactile examination and DIAGNOdent before and after root scaling. The sensitivity and specificity of different cut-off DIAGNOdent values in diagnosing root caries with reference to visual-tactile criteria were evaluated on those root surfaces without visible plaque/calculus. The DIAGNOdent values from sound and carious root surfaces were compared using the nonparametric Mann-Whitney U-test. The level of statistical significance was set at 0.05. On root surfaces without plaque/calculus, significantly different (p 0.05). Furthermore, on root surfaces with visible calculus, all DIAGNOdent readings obtained from sound root surfaces were > 50, which might be misinterpreted as carious. After scaling, the DIAGNOdent readings obtained from sound root surfaces (8.1 ± 11.3), active carious root surfaces (37.9 ± 31.9) and inactive carious root surfaces (24.9 ± 11.5) presented significant differences (p calculus before scaling, but the combined sensitivity and specificity are both around 70%. These findings suggest that on exposed, unfilled root surfaces without visible plaque/calculus, DIAGNOdent can be used as an adjunct to the visual-tactile criteria in detecting root-surface status without pre-treatment by dental scaling.

  16. Finding the Root Causes of Statistical Inconsistency in Community Earth System Model Output

    Science.gov (United States)

    Milroy, D.; Hammerling, D.; Baker, A. H.

    2017-12-01

    Baker et al (2015) developed the Community Earth System Model Ensemble Consistency Test (CESM-ECT) to provide a metric for software quality assurance by determining statistical consistency between an ensemble of CESM outputs and new test runs. The test has proved useful for detecting statistical difference caused by compiler bugs and errors in physical modules. However, detection is only the necessary first step in finding the causes of statistical difference. The CESM is a vastly complex model comprised of millions of lines of code which is developed and maintained by a large community of software engineers and scientists. Any root cause analysis is correspondingly challenging. We propose a new capability for CESM-ECT: identifying the sections of code that cause statistical distinguishability. The first step is to discover CESM variables that cause CESM-ECT to classify new runs as statistically distinct, which we achieve via Randomized Logistic Regression. Next we use a tool developed to identify CESM components that define or compute the variables found in the first step. Finally, we employ the application Kernel GENerator (KGEN) created in Kim et al (2016) to detect fine-grained floating point differences. We demonstrate an example of the procedure and advance a plan to automate this process in our future work.

  17. Formação e estabilização de agregados pelo sistema radicular de braquiária em um Nitossolo Vermelho Formation and stabilization of aggregates by the grass root system in an Oxisol

    Directory of Open Access Journals (Sweden)

    Eliane Duarte Brandão

    2012-07-01

    Full Text Available As gramíneas atuam de maneira direta na formação e na estabilização de agregados do solo, devido à maior densidade de raízes e à liberação de exsudatos orgânicos no solo. O objetivo do trabalho foi avaliar os efeitos do sistema radicular da Brachiaria ruziziensis Germain et Evrard na formação e na estabilização de agregados de um Nitossolo Vermelho. O experimento foi conduzido em abrigo telado, utilizando-se solo coletado na camada de 0-20cm de profundidade. O solo foi destorroado manualmente e passado em peneira de 2,00mm de abertura de malha e, posteriormente, separadas por classes de diâmetro de agregados de 2,00-1,00, 1,00-0,50 e 0,50-0,25mm com auxílio de peneiras de malhas específicas. O delineamento utilizado foi o inteiramente casualizado, em esquema fatorial 3x2x2x4, correspondendo a três classes de diâmetro de agregados (2,00-1,00, 1,00-0,50 e 0,50-0,25mm, duas condições de cultivo (com e sem gramínea, dois conteúdos de umidade (100% e 60% de água disponível e quatro épocas de avaliação (90, 180, 270 e 360 dias após o plantio da gramínea, com quatro repetições. As amostras de agregados foram acondicionadas em vasos de polietileno com capacidade para 10kg. O conteúdo de umidade foi equilibrado através de irrigações a cada dois dias. As amostragens foram realizadas a cada três meses, determinando-se o diâmetro médio ponderado de agregados secos ao ar (DMPAs, o diâmetro médio ponderado de agregado estáveis em água (DMPAu e o índice de estabilidade dos agregados (IEA = DMPAu/DMPAs. Verificaram-se maiores valores de DMPAu e de IEA para o tratamento com gramínea, indicando que o sistema radicular da Brachiaria ruziziensis favoreceu maior formação e estabilização dos agregados no solo.Grasses take direct action in the formation and stabilization of soil aggregates due to the density of roots and the release of organic exudates in soil. The objective of this study was to evaluate the effects of

  18. Salinity altered root distribution and increased diversity of bacterial communities in the rhizosphere soil of Jerusalem artichoke

    Science.gov (United States)

    Yang, Hui; Hu, Jinxiang; Long, Xiaohua; Liu, Zhaopu; Rengel, Zed

    2016-02-01

    The interaction between roots and bacterial communities in halophytic species is poorly understood. Here, we used Jerusalem artichoke cultivar Nanyu 1 (NY-1) to characterise root distribution patterns and determine diversity and abundance of bacteria in the rhizosphere soil under variable salinity. Root growth was not inhibited within the salinity range 1.2 to 1.9 g salt/kg, but roots were mainly confined to 0-20 cm soil layer vertically and 0-30 cm horizontally from the plant centre. Root concentrations of K+, Na+, Mg2+ and particularly Ca2+ were relatively high under salinity stress. High salinity stress decreased soil invertase and catalase activity. Using a next-generation, Illumina-based sequencing approach, we determined higher diversity of bacteria in the rhizosphere soil at high than low salinity. More than 15,500 valid reads were obtained, and Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria predominated in all samples, accounting for >80% of the reads. On a genus level, 636 genera were common to the low and high salinity treatments at 0-5 cm and 5-10 cm depth. The abundance of Steroidobacter and Sphingomonas was significantly decreased by increasing salinity. Higher Shannon and Chao 1 indices with increasing severity of salt stress indicated that high salt stress increased diversity in the bacterial communities.

  19. Isolation of Antagonistic Endophytes from Banana Roots against Meloidogyne javanica and Their Effects on Soil Nematode Community

    Directory of Open Access Journals (Sweden)

    Lanxi Su

    2017-10-01

    Full Text Available Banana production is seriously hindered by Meloidogyne spp. all over the world. Endophytes are ideal candidates compared to pesticides as an environmentally benign agent. In the present study, endophytes isolated from banana roots infected by Meloidogyne spp. with different disease levels were tested in vitro, and in sterile and nature banana monoculture soils against Meloidogyne javanica. The proportion of antagonistic endophytes were higher in the roots of middle and high disease levels. Among those, bacteria were dominant, and Pseudomonas spp., Bacillus spp. and Streptomyces spp. showed more abundant populations. One strain, named as SA, with definite root inner-colonization ability was isolated and identified as Streptomyces sp. This strain showed an inhibiting rate of >50% in vitro and biocontrol efficiency of 70.7% in sterile soil against Meloidogyne javanica, compared to the control. Greenhouse experiment results showed that the strain SA exhibits excellent biological control ability for plant-parasites both in roots and in root-knot nematode infested soil. SA treatment showed a higher number of bacterivores, especially Mesorhabditis and Cephalobus. The maturity index was significantly lower, while enrichment index (EI was significantly higher in the SA treatment. In conclusion, this study presents an important potential application of the endophytic strain Streptomyces sp. for the control of plant-parasitic nematodes, especially Meloidogyne javanica, and presents the effects on the associated variation of the nematode community.

  20. Diversity and function of the microbial community on anodes of sediment microbial fuel cells fueled by root exudates

    Energy Technology Data Exchange (ETDEWEB)

    Cabezas da Rosa, Angela

    2010-11-26

    Anode microbial communities are essential for current production in microbial fuel cells. Anode reducing bacteria are capable of using the anode as final electron acceptor in their respiratory chain. The electrons delivered to the anode travel through a circuit to the cathode where they reduce oxygen to water generating an electric current. A novel type of sediment microbial fuel cell (SMFC) harvest energy from photosynthetically derived compounds released through the roots. Nothing is known about anode microbial communities of this type of microbial fuel cell. This work consists of three parts. The first part focuses on the study of bacterial and archaeal community compositions on anodes of SMFCs fueled by rice root exudates. By using terminal restriction fragment length polymorphism (T-RFLP), a profiling technique, and cloning / sequencing of 16S rRNA, we determined that the support type used for the plant (vermiculite, potting soil or rice field soil) is an important factor determining the composition of the microbial community. Finally, by comparing microbial communities of current producing anodes and non-current producing controls we determined that Desulfobulbus- and Geobacter-related populations were probably most important for current production in potting soil and rice field soil SMFCs, respectively. However, {delta}-proteobacterial Anaeromyxobacter spp., unclassified {delta}-proteobacteria and Anaerolineae were also part of the anode biofilm in rice field soil SMFCs and these populations might also play a role in current production. Moreover, distinct clusters of Geobacter and Anaeromyxobacter populations were stimulated by rice root exudates. Regarding Archaea, uncultured Euryarchaea were abundant on anodes of potting soil SMFCs indicating a potential role in current production. In both, rice field soil and potting soil SMFCs, a decrease of Methanosaeta, an acetotrophic methanogen, was detected on current producing anodes. In the second part we focused

  1. VAM populations in relation to grass invasion associated with forest decline.

    Science.gov (United States)

    Vosatka, M; Cudlin, P; Mejstrik, V

    1991-01-01

    Spruce stands in Northern Bohemia forests, damaged to various degrees by industrial pollution, have shown establishment of grass cover following tree defoliation. Populations of vesicular-arbuscular mycorrhizal (VAM) fungi were studied under this grass cover in four permanent plots with spruce under different levels of pollution stress. Soil and root samples were collected in April and June within each plot as follows: (1) sites without grass, (2) sites with initial stages of grass invasion, and (3) sites with fully developed grass cover. In all plots, the highest number of propagules were recovered from samples taken from sites having full grass cover. Mycorrhizal infection of grass was highest in the plot with the severest pollution damage and lowest in the least damaged plot. The development of grass cover and VAM infection of grass increased with tree defoliation caused by air pollution.

  2. Plant Growth Promotion Potential Is Equally Represented in Diverse Grapevine Root-Associated Bacterial Communities from Different Biopedoclimatic Environments

    Directory of Open Access Journals (Sweden)

    Ramona Marasco

    2013-01-01

    Full Text Available Plant-associated bacteria provide important services to host plants. Environmental factors such as cultivar type and pedoclimatic conditions contribute to shape their diversity. However, whether these environmental factors may influence the plant growth promoting (PGP potential of the root-associated bacteria is not widely understood. To address this issue, the diversity and PGP potential of the bacterial assemblage associated with the grapevine root system of different cultivars in three Mediterranean environments along a macrotransect identifying an aridity gradient were assessed by culture-dependent and independent approaches. According to 16S rRNA gene PCR-DGGE, the structure of endosphere and rhizosphere bacterial communities was highly diverse (P=0.03 and was associated with a cultivar/latitudinal/climatic effect. Despite being diverse, the bacterial communities associated with Egyptian grapevines shared a higher similarity with the Tunisian grapevines than those cultivated in North Italy. A similar distribution, according to the cultivar/latitude/aridity gradients, was observed for the cultivable bacteria. Many isolates (23% presented in vitro multiple stress resistance capabilities and PGP activities, the most frequent being auxin synthesis (82%, insoluble phosphate solubilisation (61%, and ammonia production (70%. The comparable numbers and types of potential PGP traits among the three different environmental settings indicate a strong functional homeostasis of beneficial bacteria associated with grape root.

  3. Composition of the root mycorrhizal community associated with Coffea arabica in Fifa Mountains (Jazan region, Saudi Arabia).

    Science.gov (United States)

    Mahdhi, Mosbah; Tounekti, Taieb; Al-Turki, Turki Ali; Khemira, Habib

    2017-08-01

    Arbuscular mycorrhizal fungi (AMF) constitute a key functional group of soil biota that can greatly contribute to crop productivity and ecosystem sustainability. They improve nutrient uptake and enhance the ability of plants to cope with abiotic stresses. The presence of AMF in coffee (Coffea arabica L.) plant roots have been reported in several locations but not in Saudi Arabia despite the fact that coffee has been in cultivation here since ancient times. The objective of the present study was to investigate the diversity of AMF communities colonizing the roots of coffee trees growing in two sites of Fifa Mountains (south-west Saudi Arabia): site 1 at 700 m altitude and site 2 at 1400 m. The AMF large subunit rDNA regions (LSU) were subjected to nested PCR, cloning, sequencing, and phylogenetic analysis. Microscopic observations indicated higher mycorrhizal intensity (24.3%) and spore density (256 spores/100 g of soil) in site 2 (higher altitude). Phylogenetic analysis revealed 10 phylotypes, six belonging to the family Glomeraceae, two to Claroideoglomercea, one to Acaulosporaceae and one to Gigasporaceae family. Glomus was the dominant genus at both sites and the genus Gigaspora was detected only at site 2. This is the first study reporting the presence of AMF in coffee roots and the composition of this particular mycorrhizal community in Saudi Arabia. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Grass-on-grass competition along a catenal gradient in mesic ...

    African Journals Online (AJOL)

    Three aboveground treatments (full light competition, no light competition and clipping to simulate grazing), and two belowground treatments (full belowground competition and belowground competition excluded by a root tube), were used. On all soil depths the three grass species differed in mean mass, with E. racemosa ...

  5. MACRO NUTRIENTS UPTAKE OF FORAGE GRASSES AT DIFFERENT SALINITY STRESSES

    Directory of Open Access Journals (Sweden)

    F. Kusmiyati

    2014-10-01

    Full Text Available The high concentration of sodium chloride (NaCl in saline soils has negative effects on the growth ofmost plants. The experiment was designed to evaluate macro nutrient uptake (Nitrogen, Phosphorus andPotassium of forage grasses at different NaCl concentrations in growth media. The experiment wasconducted in a greenhouse at Forage Crops Laboratory of Animal Agriculture Faculty, Diponegoro University.Split plot design was used to arrange the experiment. The main plot was forage grasses (Elephant grass(Pennisetum purpureum and King grass (Pennisetum hybrida. The sub plot was NaCl concentrationin growth media (0, 150, and 300 mM. The nitrogen (N, phosphorus (P and potassium (K uptake in shootand root of plant were measured. The result indicated increasing NaCl concentration in growth mediasignificantly decreased the N, P and K uptake in root and shoot of the elephant grass and king grass. Thepercentage reduction percentage of N, P and K uptake at 150 mM and 300 mM were high in elephant grassand king grass. It can be concluded that based on nitrogen, phosphorus and potassium uptake, elephantgrass and king grass are not tolerant to strong and very strong saline soil.

  6. Competition for phosphorus: differential uptake from dual-isotope-labeled soil interspaces between shrub and grass

    International Nuclear Information System (INIS)

    Caldwell, M.M.; Eissenstat, D.M.; Richards, J.H.; Allen, M.F.

    1985-01-01

    Two species of Agropyron grass differed strikingly in their capacity to compete for phosphate in soil interspaces shared with a common competitor, the sagebrush Artemisia tridentata. Of the total phosphorus-32 and -33 absorbed by Artemisia, 86% was from the interspace shared with Agropyron spicatum and only 14% from that shared with Agropyron desertorum. Actively absorbing mycorrhizal roots of Agropyron and Artemisia were present in both interspaces, where competition for the labeled phosphate occurred. The results have important implications about the way in which plants compete for resources below ground in both natural plant communities and agricultural intercropping systems

  7. Rehabilitation experiment by phytoremediation using lawn grass

    International Nuclear Information System (INIS)

    2012-08-01

    Measures against environmental contamination by radioactive materials originated from the Fukushima Nuclear Accident (May, 2011), are being conducted in Fukushima and surrounding prefectures. Regarding to the measures, a phytoremediation experiment with several types of lawn grasses in a field scale have been carried out. Lawn grasses are generally characterized by shallow rhizosphere, high density and root mat formation. Decontamination effectiveness of radioactive cesium by plant uptake and by sod removing was investigated. As a result, the range of decontamination factors by plant uptake was below than 1% because of low transfer rate form soil to plant. On the other hand, maximum decontamination factor by sod removing reached about 100%. Decontamination activities with various methods will be implemented according to the national decontamination policy and related plans in each municipality. The phytoremediation method with lawn grass would be applicable in limited circumstances. (author)

  8. Compositional differences in simulated root exudates elicit a limited functional and compositional response in soil microbial communities

    Directory of Open Access Journals (Sweden)

    Michael S Strickland

    2015-08-01

    Full Text Available Inputs of low molecular weight carbon (LMW-C to soil −primarily via root exudates− are expected to be a major driver of microbial activity and source of stable soil organic carbon. It is expected that variation in the type and composition of LMW-C entering soil will influence microbial community composition and function. If this is the case then short-term changes in LMW-C inputs may alter processes regulated by these communities. To determine if change in the composition of LMW-C inputs influences microbial community function and composition, we conducted a 90 day microcosm experiment whereby soils sourced from three different land covers (meadows, deciduous forests, and white pine stands were amended, at low concentrations, with one of eight simulated root exudate treatments. Treatments included no addition of LMW-C, and the full factorial combination of glucose, glycine, and oxalic acid. After 90 days, we conducted a functional response assay and determined microbial composition via phospholipid fatty acid analysis. Whereas we noted a statistically significant effect of exudate treatments, this only accounted for ~3% of the variation observed in function. In comparison, land cover and site explained ~46 and ~41% of the variation, respectively. This suggests that exudate composition has little influence on function

  9. Compositional differences in simulated root exudates elicit a limited functional and compositional response in soil microbial communities.

    Science.gov (United States)

    Strickland, Michael S; McCulley, Rebecca L; Nelson, Jim A; Bradford, Mark A

    2015-01-01

    Inputs of low molecular weight carbon (LMW-C) to soil - primarily via root exudates- are expected to be a major driver of microbial activity and source of stable soil organic carbon. It is expected that variation in the type and composition of LMW-C entering soil will influence microbial community composition and function. If this is the case then short-term changes in LMW-C inputs may alter processes regulated by these communities. To determine if change in the composition of LMW-C inputs influences microbial community function and composition, we conducted a 90 day microcosm experiment whereby soils sourced from three different land covers (meadows, deciduous forests, and white pine stands) were amended, at low concentrations, with one of eight simulated root exudate treatments. Treatments included no addition of LMW-C, and the full factorial combination of glucose, glycine, and oxalic acid. After 90 days, we conducted a functional response assay and determined microbial composition via phospholipid fatty acid analysis. Whereas we noted a statistically significant effect of exudate treatments, this only accounted for ∼3% of the variation observed in function. In comparison, land cover and site explained ∼46 and ∼41% of the variation, respectively. This suggests that exudate composition has little influence on function compared to site/land cover specific factors. Supporting the finding that exudate effects were minor, we found that an absence of LMW-C elicited the greatest difference in function compared to those treatments receiving any LMW-C. Additionally, exudate treatments did not alter microbial community composition and observable differences were instead due to land cover. These results confirm the strong effects of land cover/site legacies on soil microbial communities. In contrast, short-term changes in exudate composition, at meaningful concentrations, may have little impact on microbial function and composition.

  10. Root herbivory indirectly affects above- and below-ground community members and directly reduces plant performance

    NARCIS (Netherlands)

    Barber, N.A.; Milano, N.J.; Kiers, E.T.; Theis, N.; Bartolo, V.; Hazzard, R.V.; Adler, L.S.

    2015-01-01

    There is a widespread recognition that above- and below-ground organisms are linked through their interactions with host plants that span terrestrial subsystems. In addition to direct effects on plants, soil organisms such as root herbivores can indirectly alter interactions between plants and other

  11. Rice rhizosphere soil and root surface bacterial community response to water management changes

    Science.gov (United States)

    Different water management practices could affect microbial populations in the rice rhizosphere. A field-scale study was conducted to evaluate microbial populations in the root plaque and rhizosphere of rice in response to continuous and intermittent flooding conditions. Microbial populations in rhi...

  12. Comparison of root-associated communities of native and non-native ectomycorrhizal hosts in an urban landscape.

    Science.gov (United States)

    Lothamer, K; Brown, S P; Mattox, J D; Jumpponen, A

    2014-05-01

    Non-native tree species are often used as ornamentals in urban landscapes. However, their root-associated fungal communities remain yet to be examined in detail. Here, we compared richness, diversity and community composition of ectomycorrhizosphere fungi in general and ectomycorrhizal (EcM) fungi in particular between a non-native Pinus nigra and a native Quercus macrocarpa across a growing season in urban parks using 454-pyrosequencing. Our data show that, while the ectomycorrhizosphere community richness and diversity did not differ between the two host, the EcM communities associated with the native host were often more species rich and included more exclusive members than those of the non-native hosts. In contrast, the ectomycorrhizosphere communities of the two hosts were compositionally clearly distinct in nonmetric multidimensional ordination analyses, whereas the EcM communities were only marginally so. Taken together, our data suggest EcM communities with broad host compatibilities and with a limited numbers of taxa with preference to the non-native host. Furthermore, many common fungi in the non-native Pinus were not EcM taxa, suggesting that the fungal communities of the non-native host may be enriched in non-mycorrhizal fungi at the cost of the EcM taxa. Finally, while our colonization estimates did not suggest a shortage in EcM inoculum for either host in urban parks, the differences in the fungi associated with the two hosts emphasize the importance of using native hosts in urban environments as a tool to conserve endemic fungal diversity and richness in man-made systems.

  13. No positive feedback between fire and a nonnative perennial grass

    Science.gov (United States)

    Erika L. Geiger; Guy R. McPherson

    2005-01-01

    Semi-desert grasslands flank the “Sky Island” mountains in southern Arizona and Northern Mexico. Many of these grasslands are dominated by nonnative grasses, which potentially alter native biotic communities. One specific concern is the potential for a predicted feedback between nonnative grasses and fire. In a large-scale experiment in southern Arizona we investigated...

  14. Agricultural field reclamation utilizing native grass crop production

    Science.gov (United States)

    J. Cure

    2013-01-01

    Developing a method of agricultural field reclamation to native grasses in the Lower San Pedro Watershed could prove to be a valuable tool for educational and practical purposes. Agricultural field reclamation utilizing native grass crop production will address water table depletion, soil degradation and the economic viability of the communities within the watershed....

  15. It Takes a Rooted Village: Networked Resistance, Connected Communities, and Adaptive Responses to Forest Tenure Reform in Northern Thailand

    Directory of Open Access Journals (Sweden)

    Kimberly Roberts

    2016-06-01

    Full Text Available Conflicts persist between forest dwelling communities and advocates of forest conservation. In Thailand, a community forestry bill and national park expansion initiatives leave little space for communities. The article analyzes the case of the predominantly ethnic Black Lahu village of Huai Lu Luang in Chiang Rai province that has resisted the threats posed by a community forestry bill and a proposed national park. The villagers reside on a national forest reserve and have no de jure rights to the land. This article argues, however, that through its network rooted in place and connected to an assemblage of civil society, local government, and NGOs, Huai Lu Luang has been able to stall efforts by the Thai government that would detrimentally impact their use of and access to forest resources. Their resistance is best understood not in isolation – as one victimized community resisting threats to their livelihoods – but in connection to place, through dynamic assemblages. A ‘rooted’ networks approach follows the connections and nodes of Huai Lu Luang’s network that influence and aid the village’s attempts to resist forest tenure reform.

  16. Genetic compatibility determines endophyte-grass combinations.

    Directory of Open Access Journals (Sweden)

    Kari Saikkonen

    Full Text Available Even highly mutually beneficial microbial-plant interactions, such as mycorrhizal- and rhizobial-plant exchanges, involve selfishness, cheating and power-struggles between the partners, which depending on prevailing selective pressures, lead to a continuum of interactions from antagonistic to mutualistic. Using manipulated grass-endophyte combinations in a five year common garden experiment, we show that grass genotypes and genetic mismatches constrain genetic combinations between the vertically (via host seeds transmitted endophytes and the out-crossing host, thereby reducing infections in established grass populations. Infections were lost in both grass tillers and seedlings in F(1 and F(2 generations, respectively. Experimental plants were collected as seeds from two different environments, i.e., meadows and nearby riverbanks. Endophyte-related benefits to the host included an increased number of inflorescences, but only in meadow plants and not until the last growing season of the experiment. Our results illustrate the importance of genetic host specificity and trans-generational maternal effects on the genetic structure of a host population, which act as destabilizing forces in endophyte-grass symbioses. We propose that (1 genetic mismatches may act as a buffering mechanism against highly competitive endophyte-grass genotype combinations threatening the biodiversity of grassland communities and (2 these mismatches should be acknowledged, particularly in breeding programmes aimed at harnessing systemic and heritable endophytes to improve the agriculturally valuable characteristics of cultivars.

  17. Elevated CO2 and O3 effects on ectomycorrhizal fungal root tip communities in consideration of a post-agricultural soil nutrient gradient legacy

    Science.gov (United States)

    Carrie Andrew; Erik A. Lilleskov

    2014-01-01

    Despite the critical role of EMF in nutrient and carbon (C) dynamics, combined effects of global atmospheric pollutants on ectomycorrhizal fungi (EMF) are unclear. Here, we present research on EMF root-level community responses to elevated CO2 and O3. We discovered that belowground EMF community richness and similarity were...

  18. resistance of napier grass clones to napier grass stunt disease

    African Journals Online (AJOL)

    ACSS

    Napier grass (Pennisetum purpureum Schumach) is the major livestock fodder under intensive and semi-intensive systems in East Africa. However, the productivity of the grass is constrained by Napier grass Stunt Disease. (NSD). The purpose of this study was to identify Napier grass clones with resistance to NSD.

  19. Resistance of Napier grass clones to Napier grass Stunt Disease ...

    African Journals Online (AJOL)

    Napier grass (Pennisetum purpureum Schumach) is the major livestock fodder under intensive and semi-intensive systems in East Africa. However, the productivity of the grass is constrained by Napier grass Stunt Disease (NSD). The purpose of this study was to identify Napier grass clones with resistance to NSD.

  20. Evaluation of the suitability of root cause analysis frameworks for the investigation of community-acquired pressure ulcers: a systematic review and documentary analysis.

    Science.gov (United States)

    McGraw, Caroline; Drennan, Vari M

    2015-02-01

    To evaluate the suitability of root cause analysis frameworks for the investigation of community-acquired pressure ulcers. The objective was to identify the extent to which these frameworks take account of the setting where the ulcer originated as being the person's home rather than a hospital setting. Pressure ulcers involving full-thickness skin loss are increasingly being regarded as indicators of nursing patient safety failure, requiring investigation using root cause analysis frameworks. Evidence suggests that root cause analysis frameworks developed in hospital settings ignore the unique dimensions of risk in home healthcare settings. A systematic literature review and documentary analysis of frameworks used to investigate community-acquired grade three and four pressure ulcers by home nursing services in England. No published papers were identified for inclusion in the review. Fifteen patient safety investigative frameworks were collected and analysed. Twelve of the retrieved frameworks were intended for the investigation of community-acquired pressure ulcers; seven of which took account of the setting where the ulcer originated as being the patient's home. This study provides evidence to suggest that many of the root cause analysis frameworks used to investigate community-acquired pressure ulcers in England are unsuitable for this purpose. This study provides researchers and practitioners with evidence of the need to develop appropriate home nursing root cause analysis frameworks to investigate community-acquired pressure ulcers. © 2014 John Wiley & Sons Ltd.

  1. Changes in rainfall amount and frequency do not affect the outcome of the interaction between the shrub Retama sphaerocarpa and its neighbouring grasses in two semiarid communities

    Science.gov (United States)

    Soliveres, Santiago; García-Palacios, Pablo; Maestre, Fernando T.; Escudero, Adrián; Valladares, Fernando

    2015-01-01

    We evaluated the net outcome of the interaction between the shrub Retama sphaerocarpa, our target plant, and different herbaceous neighbours in response to changes in the magnitude and frequency of rainfall events during three years. The experiment was conducted in natural and anthropogenic grasslands dominated by a perennial stress-tolerator and ruderal annual species, respectively. In spite of the neutral or positive effects of neighbours on water availability, neighbouring plants reduced the performance of Retama juveniles, suggesting competition for resources other than water. The negative effects of grasses on the photochemical efficiency of Retama juveniles decreased with higher water availabilities or heavier irrigation pulses, depending on the grassland studied; however, these effects did not extent to the survival and growth of Retama juveniles. Our findings show the prevalence of competitive interactions among the studied plants, regardless of the water availability and its temporal pattern. These results suggest that positive interactions may not prevail under harsher conditions when shade-intolerant species are involved. This study could be used to further refine our predictions of how plant-plant interactions will respond to changes in rainfall, either natural or increased by the ongoing climatic change, in ecosystems where grass-shrubs interactions are prevalent. PMID:25914429

  2. Changes in rainfall amount and frequency do not affect the outcome of the interaction between the shrub Retama sphaerocarpa and its neighbouring grasses in two semiarid communities.

    Science.gov (United States)

    Soliveres, Santiago; García-Palacios, Pablo; Maestre, Fernando T; Escudero, Adrián; Valladares, Fernando

    2013-04-01

    We evaluated the net outcome of the interaction between the shrub Retama sphaerocarpa , our target plant, and different herbaceous neighbours in response to changes in the magnitude and frequency of rainfall events during three years. The experiment was conducted in natural and anthropogenic grasslands dominated by a perennial stress-tolerator and ruderal annual species, respectively. In spite of the neutral or positive effects of neighbours on water availability, neighbouring plants reduced the performance of Retama juveniles, suggesting competition for resources other than water. The negative effects of grasses on the photochemical efficiency of Retama juveniles decreased with higher water availabilities or heavier irrigation pulses, depending on the grassland studied; however, these effects did not extent to the survival and growth of Retama juveniles. Our findings show the prevalence of competitive interactions among the studied plants, regardless of the water availability and its temporal pattern. These results suggest that positive interactions may not prevail under harsher conditions when shade-intolerant species are involved. This study could be used to further refine our predictions of how plant-plant interactions will respond to changes in rainfall, either natural or increased by the ongoing climatic change, in ecosystems where grass-shrubs interactions are prevalent.

  3. Nowcasting daily minimum air and grass temperature

    Science.gov (United States)

    Savage, M. J.

    2016-02-01

    Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence, using measured sub-hourly temperatures hours earlier in the morning as model inputs, was investigated. Various temperature models were tested for their ability to accurately nowcast daily minimum temperatures 2 or 4 h before sunrise. Temperature datasets used for the model nowcasts included sub-hourly grass and grass-surface (infrared) temperatures from one location in South Africa and air temperature from four subtropical sites varying in altitude (USA and South Africa) and from one site in central sub-Saharan Africa. Nowcast models used employed either exponential or square root functions to describe the rate of nighttime temperature decrease but inverted so as to determine the minimum temperature. The models were also applied in near real-time using an open web-based system to display the nowcasts. Extrapolation algorithms for the site-specific nowcasts were also implemented in a datalogger in an innovative and mathematically consistent manner. Comparison of model 1 (exponential) nowcasts vs measured daily minima air temperatures yielded root mean square errors (RMSEs) <1 °C for the 2-h ahead nowcasts. Model 2 (also exponential), for which a constant model coefficient ( b = 2.2) was used, was usually slightly less accurate but still with RMSEs <1 °C. Use of model 3 (square root) yielded increased RMSEs for the 2-h ahead comparisons between nowcasted and measured daily minima air temperature, increasing to 1.4 °C for some sites. For all sites for all models, the comparisons for the 4-h ahead air temperature nowcasts generally yielded increased RMSEs, <2.1 °C. Comparisons for all model nowcasts of the daily grass

  4. Potential of grasses and rhizosphere bacteria for bioremediation of diesel-contaminated soils

    Directory of Open Access Journals (Sweden)

    Melissa Paola Mezzari

    2011-12-01

    Full Text Available The techniques available for the remediation of environmental accidents involving petroleum hydrocarbons are generally high-cost solutions. A cheaper, practical and ecologically relevant alternative is the association of plants with microorganisms that contribute to the degradation and removal of hydrocarbons from the soil. The growth of three tropical grass species (Brachiaria brizantha, Brachiaria decumbens and Paspalum notatum and the survival of root-associated bacterial communities was evaluated at different diesel oil concentrations. Seeds of three grass species were germinated in greenhouse and at different doses of diesel (0, 2.5, 5 and 10 g kg-1 soil. Plants were grown for 10 weeks with periodic assessment of germination, growth (fresh and dry weight, height, and number of bacteria in the soil (pots with or without plants. Growth and biomass of B. decumbens and P. notatum declined significantly when planted in diesel-oil contaminated soils. The presence of diesel fuel did not affect the growth of B. brizantha, which was highly tolerant to this pollutant. Bacterial growth was significant (p < 0.05 and the increase was directly proportional to the diesel dose. Bacteria growth in diesel-contaminated soils was stimulated up to 5-fold by the presence of grasses, demonstrating the positive interactions between rhizosphere and hydrocarbon-degrading bacteria in the remediation of diesel-contaminated soils.

  5. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants

    Czech Academy of Sciences Publication Activity Database

    Janoušková, Martina; Krak, Karol; Vosátka, Miroslav; Püschel, David; Štorchová, Helena

    2017-01-01

    Roč. 12, č. 7 (2017), s. 1-21, č. článku e0181525. E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) LH14285 Institutional support: RVO:67985939 ; RVO:61389030 Keywords : inoculation * arbuscular mycorrhiza * community Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (UEB-Q) OBOR OECD: Plant sciences, botany; Plant sciences, botany (UEB-Q) Impact factor: 2.806, year: 2016

  6. Copolymers enhance selective bacterial community colonization for potential root zone applications.

    Science.gov (United States)

    Pham, Vy T H; Murugaraj, Pandiyan; Mathes, Falko; Tan, Boon K; Truong, Vi Khanh; Murphy, Daniel V; Mainwaring, David E

    2017-11-21

    Managing the impact of anthropogenic and climate induced stress on plant growth remains a challenge. Here we show that polymeric hydrogels, which maintain their hydrous state, can be designed to exploit functional interactions with soil microorganisms. This microbial enhancement may mitigate biotic and abiotic stresses limiting productivity. The presence of mannan chains within synthetic polyacrylic acid (PAA) enhanced the dynamics and selectivity of bacterial ingress in model microbial systems and soil microcosms. Pseudomonas fluorescens exhibiting high mannan binding adhesins showed higher ingress and localised microcolonies throughout the polymeric network. In contrast, ingress of Bacillus subtilis, lacking adhesins, was unaltered by mannan showing motility comparable to bulk liquids. Incubation within microcosms of an agricultural soil yielded hydrogel populations significantly increased from the corresponding soil. Bacterial diversity was markedly higher in mannan containing hydrogels compared to both control polymer and soil, indicating enhanced selectivity towards microbial families that contain plant beneficial species. Here we propose functional polymers applied to the potential root zone which can positively influence rhizobacteria colonization and potentially plant growth as a new approach to stress tolerance.

  7. Endophytic bacterial community living in roots of healthy and 'Candidatus Phytoplasma mali'-infected apple (Malus domestica, Borkh.) trees.

    Science.gov (United States)

    Bulgari, Daniela; Bozkurt, Adem I; Casati, Paola; Cağlayan, Kadriye; Quaglino, Fabio; Bianco, Piero A

    2012-11-01

    'Candidatus Phytoplasma mali', the causal agent of apple proliferation (AP) disease, is a quarantine pathogen controlled by chemical treatments against insect vectors and eradication of diseased plants. In accordance with the European Community guidelines, novel strategies should be developed for sustainable management of plant diseases by using resistance inducers (e.g. endophytes). A basic point for the success of this approach is the study of endophytic bacteria associated with plants. In the present work, endophytic bacteria living in healthy and 'Ca. Phytoplasma mali'-infected apple trees were described by cultivation-dependent and independent methods. 16S rDNA sequence analysis showed the presence of the groups Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, Chlamydiae, and Firmicutes. In detail, library analyses underscored 24 and 17 operational taxonomic units (OTUs) in healthy and infected roots, respectively, with a dominance of Betaproteobacteria. Moreover, differences in OTUs number and in CFU/g suggested that phytoplasmas could modify the composition of endophytic bacterial communities associated with infected plants. Intriguingly, the combination of culturing methods and cloning analysis allowed the identification of endophytic bacteria (e.g. Bacillus, Pseudomonas, and Burkholderia) that have been reported as biocontrol agents. Future research will investigate the capability of these bacteria to control 'Ca. Phytoplasma mali' in order to develop sustainable approaches for managing AP.

  8. Performance of Vetiver Grass (Vetiveria zizanioides for Phytoremediation of Contaminated Water

    Directory of Open Access Journals (Sweden)

    Syed Hasan Sharifah Nur Munirah

    2017-01-01

    Full Text Available In tolerance towards metal uptake, there is a need to evaluate the performance of vetiver grass for metal removal to reduce water impurity. This study was aimed to evaluate contaminant removal by vetiver grass at varying root length and plant density and determine the metal uptake in vetiver plant biomass. Pollutant uptake of vetiver grass was conducted in laboratory experiment and heavy metal analysis was done using acid digestion and Atomic Absorption Spectrometry. Findings indicated that the removal of heavy metal was decreased in seven days of the experiment where iron shows the highest percentage (96%; 0.42 ppm of removal due to iron is highly required for growth of vetiver grass. Removal rate of heavy metals in water by vetiver grass is ranked in the order of Fe>Zn>Pb>Mn>Cu. Results also demonstrated greater removal of heavy metals (Cu, Fe, Mn, Pb, Zn at greater root length and higher density of vetiver grass because it increased the surface area for metal absorption by plant root into vetiver plant from contaminated water. However, findings indicated that accumulation of heavy metals in plant biomass was higher in vetiver shoot than in root due to metal translocation from root to the shoot. Therefore, the findings have shown effective performance of vetiver grass for metal removal in the phytoremediation of contaminated water.

  9. Communities of arbuscular mycorrhizal fungi in the roots of Pyrus pyrifolia var. culta (Japanese pear) in orchards with variable amounts of soil-available phosphorus.

    Science.gov (United States)

    Yoshimura, Yuko; Ido, Akifumi; Iwase, Koji; Matsumoto, Teruyuki; Yamato, Masahide

    2013-01-01

    We examined the colonization rate and communities of arbuscular mycorrhizal fungi (AMF) in the roots of Pyrus pyrifolia var. culta (Japanese pear) in orchards to investigate the effect of phosphorus (P) fertilization on AMF. Soil cores containing the roots of Japanese pear were collected from 13 orchards in Tottori Prefecture, Japan. Soil-available P in the examined orchards was 75.7 to 1,200 mg kg(-1), showing the extreme accumulation of soil P in many orchards. The AMF colonization rate was negatively correlated with soil-available P (P soil-available P (P fungi may be adapted to high soil-available P conditions. Redundancy analysis showed the significant effects of soil pH, available P in soil, and P content in leaves of P. pyrifolia var. culta trees on AMF distribution. These results suggested that the accumulation of soil-available P affected AMF communities in the roots of Japanese pear in the orchard environment.

  10. Prognoses of plant community changes in the territories not used for agriculture after the accident at the Chernobyl nuclear power plant

    International Nuclear Information System (INIS)

    Timofeev, S.F.; Podolyak, A.G.; Avseenko, S.V.; Sapegin, L.M.; Dayneko, N.M.

    1997-01-01

    Science-research in the zones of eviction in the Bragin district of the Gomel region confirms interdependence between development of plants' communities and such factors as type of soil, kind of agricultural field, the term of nonuse. The study of vegetation change on the former fields, represented by turf-podsol soil, indicates that plant community has by now been formed on it, in which out of 100% projection cover prevail Artemisia absinthium L., - 40%, Artemisia campestris L. -20%, Artemisia vulgaris L. -5%, Elytrigia repens (L.) Nevski - 30%. On lower lots, represented by turf-podsol swampy soil, prevail Elytrigia repens - 60%, Artemisia absinthium -20%, Erigeron canadensis - 10%. So, on the unused arable land the tendency to form communities of Elytrigia repens is observed. In 10-15 years there may be a community here, consisting of bunch-grasses an densely turfed grasses. On the haymaking and pasture meadows, sowing plants are replaced by rhizome bunch-grasses (Poa pratensis L.) rhizome (Elytrigia repens) and diverse grasses (Artemisia absinthium, Achillea millefolium, Erigeron canadensis and others). On sowing meadows, situated on peat-swamp soil, Urtica dioica L. took root. It formed powerful herbage with 80-90% projection cover, which prevents the renewing of grasses. Only after gradual decrease of Urtica dioica there will appear different grasses, as well as rhisome grasses. In future this land can be used for haymaking. It is impossible to use this kind of soil without herbicides in large quantity, which may create additional problems of ecological character

  11. GUI development for GRASS GIS

    Directory of Open Access Journals (Sweden)

    Martin Landa

    2007-12-01

    Full Text Available This article discusses GUI development for GRASS GIS. Sophisticated native GUI for GRASS is one of the key points (besides the new 2D/3D raster library, vector architecture improvements, etc. for the future development of GRASS. In 2006 the GRASS development team decided to start working on the new generation of GUI instead of improving the current GUI based on Tcl/Tk.

  12. Associations of Pseudomonas species and forage grasses enhance degradation of chlorinated benzoic acids in soil

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, S. D.

    1998-12-01

    Using chlorinated benzoic acid (CBA) as a model compound, this study attempted to show that microorganisms and plants can be used as bioremediation agents to clean up contaminated soil sites in a cost effective and environmentally friendly manner. CBA was used because it is present in soils contaminated with polychlorinated biphenyls (PCBs), or chlorinated pesticides. Sixteen forage grasses were screened in combination with 12 bacterial inoculants for their ability to promote the degradation of CBA in soil. Five associations of plants and bacteria were found to degrade CBA to a greater extent than plants without bacterial inoculants. Bacterial inoculants were shown to stimulate CBA degradation by altering the microbial community present on the root surface and thereby increasing the ability of this community to degrade CBA.

  13. [Mechanisms of grass in slope erosion control in Loess sandy soil region of Northwest China].

    Science.gov (United States)

    Zhao, Chun-Hong; Gao, Jian-En; Xu, Zhen

    2013-01-01

    By adopting the method of simulated precipitation and from the viewpoint of slope hydrodynamics, in combining with the analysis of soil resistance to erosion, a quantitative study was made on the mechanisms of grass in controlling the slope erosion in the cross area of wind-water erosion in Loess Plateau of Northwest China under different combinations of rainfall intensity and slope gradient, aimed to provide basis to reveal the mechanisms of vegetation in controlling soil erosion and to select appropriate vegetation for the soil and water conservation in Loess Plateau. The grass Astragalus adsurgens with the coverage about 40% could effectively control the slope erosion. This grass had an efficiency of more than 70% in reducing sediment, and the grass root had a greater effect than grass canopy. On bare slope and on the slopes with the grass plant or only the grass root playing effect, there existed a functional relation between the flow velocity on the slopes and the rainfall intensity and slope gradient (V = DJ(0.33 i 0.5), where V is flow velocity, D is the comprehensive coefficient which varies with different underlying surfaces, i is rainfall intensity, and J is slope gradient). Both the grass root and the grass canopy could markedly decrease the flow velocity on the slopes, and increase the slope resistance, but the effect of grass root in decreasing flow velocity was greater while the effect in increasing resistance was smaller than that of grass canopy. The effect of grass root in increasing slope resistance was mainly achieved by increasing the sediment grain resistance, while the effect of canopy was mainly achieved by increasing the slope form resistance and wave resistance. The evaluation of the soil resistance to erosion by using a conceptual model of sediment generation by overland flow indicated that the critical shear stress value of bare slope and of the slopes with the grass plant or only the grass root playing effect was 0.533, 1.672 and 0

  14. Fungal communities in mycorrhizal roots of conifer seedlings in forest nurseries under different cultivation systems, assessed by morphotyping, direct sequencing and mycelial isolation.

    Science.gov (United States)

    Menkis, Audrius; Vasiliauskas, Rimvydas; Taylor, Andrew F S; Stenlid, Jan; Finlay, Roger

    2005-12-01

    Fungi colonising root tips of Pinus sylvestris and Picea abies grown under four different seedling cultivation systems were assessed by morphotyping, direct sequencing and isolation methods. Roots were morphotyped using two approaches: (1) 10% of the whole root system from 30 seedlings of each species and (2) 20 randomly selected tips per plant from 300 seedlings of each species. The first approach yielded 15 morphotypes, the second yielded 27, including 18 new morphotypes. The overall community consisted of 33 morphotypes. The level of mycorrhizal colonisation of roots determined by each approach was about 50%. The cultivation system had a marked effect on the level of mycorrhizal colonisation. In pine, the highest level of colonisation (48%) was observed in bare-root systems, while in spruce, colonisation was highest in polyethylene rolls (71%). Direct internal transcribed spacer ribosomal DNA sequencing and isolation detected a total of 93 fungal taxa, including 27 mycorrhizal. A total of 71 (76.3%) fungi were identified at least to a genus level. The overlap between the two methods was low. Only 13 (13.9%) of taxa were both sequenced and isolated, 47 (50.5%) were detected exclusively by sequencing and 33 (35.5%) exclusively by isolation. All isolated mycorrhizal fungi were also detected by direct sequencing. Characteristic mycorrhizas were Phialophora finlandia, Amphinema byssoides, Rhizopogon rubescens, Suillus luteus and Thelephora terrestris. There was a moderate similarity in mycorrhizal communities between pine and spruce and among different cultivation systems.

  15. Root-associated fungal communities in three Pyroleae species and their mycobiont sharing with surrounding trees in subalpine coniferous forests on Mount Fuji, Japan.

    Science.gov (United States)

    Jia, Shuzheng; Nakano, Takashi; Hattori, Masahira; Nara, Kazuhide

    2017-11-01

    Pyroleae species are perennial understory shrubs, many of which are partial mycoheterotrophs. Most fungi colonizing Pyroleae roots are ectomycorrhizal (ECM) and share common mycobionts with their Pyroleae hosts. However, such mycobiont sharing has neither been examined in depth before nor has the interspecific variation in sharing among Pyroleae species. Here, we examined root-associated fungal communities in three co-existing Pyroleae species, including Pyrola alpina, Pyrola incarnata, and Orthilia secunda, with reference to co-existing ECM fungi on the surrounding trees in the same soil blocks in subalpine coniferous forests. We identified 42, 75, and 18 fungal molecular operational taxonomic units in P. alpina, P. incarnata, and O. secunda roots, respectively. Mycobiont sharing with surrounding trees, which was defined as the occurrence of the same mycobiont between Pyroleae and surrounding trees in each soil block, was most frequent among P. incarnata (31 of 44 plants). In P. alpina, sharing was confirmed in 12 of 37 plants, and the fungal community was similar to that of P. incarnata. Mycobiont sharing was least common in O. secunda, found in only 5 of 32 plants. Root-associated fungi of O. secunda were dominated by Wilcoxina species, which were absent from the surrounding ECM roots in the same soil blocks. These results indicate that mycobiont sharing with surrounding trees does not equally occur among Pyroleae plants, some of which may develop independent mycorrhizal associations with ECM fungi, as suggested in O. secunda at our research sites.

  16. Ectomycorrhizal Communities on the Roots of Two Beech (Fagus sylvatica) Populations from Contrasting Climates Differ in Nitrogen Acquisition in a Common Environment.

    Science.gov (United States)

    Leberecht, Martin; Dannenmann, Michael; Gschwendtner, Silvia; Bilela, Silvija; Meier, Rudolf; Simon, Judy; Rennenberg, Heinz; Schloter, Michael; Polle, Andrea

    2015-09-01

    Beech (Fagus sylvatica), a dominant forest species in Central Europe, competes for nitrogen with soil microbes and suffers from N limitation under dry conditions. We hypothesized that ectomycorrhizal communities and the free-living rhizosphere microbes from beech trees from sites with two contrasting climatic conditions exhibit differences in N acquisition that contribute to differences in host N uptake and are related to differences in host belowground carbon allocation. To test these hypotheses, young trees from the natural regeneration of two genetically similar populations, one from dryer conditions (located in an area with a southwest exposure [SW trees]) and the other from a cooler, moist climate (located in an area with a northeast exposure [NE trees]), were transplanted into a homogeneous substrate in the same environment and labeled with (13)CO2 and (15)NH4 (+). Free-living rhizosphere microbes were characterized by marker genes for the N cycle, but no differences between the rhizospheres of SW or NE trees were found. Lower (15)N enrichment was found in the ectomycorrhizal communities of the NE tree communities than the SW tree communities, whereas no significant differences in (15)N enrichment were observed for nonmycorrhizal root tips of SW and NE trees. Neither the ectomycorrhizal communities nor the nonmycorrhizal root tips originating from NE and SW trees showed differences in (13)C signatures. Because the level of (15)N accumulation in fine roots and the amount transferred to leaves were lower in NE trees than SW trees, our data support the suggestion that the ectomycorrhizal community influences N transfer to its host and demonstrate that the fungal community from the dry condition was more efficient in N acquisition when environmental constraints were relieved. These findings highlight the importance of adapted ectomycorrhizal communities for forest nutrition in a changing climate. Copyright © 2015, American Society for Microbiology. All Rights

  17. The Effects of Dynamic Root Distribution on Land–Atmosphere Carbon and Water Fluxes in the Community Earth System Model (CESM1.2.0

    Directory of Open Access Journals (Sweden)

    Yuanyuan Wang

    2018-03-01

    Full Text Available Roots are responsible for the uptake of water and nutrients by plants, and they have the plasticity to respond dynamically to different environmental conditions. However, currently, most climate models only prescribe rooting profiles as a function of the vegetation type of the land component, with no consideration of the surroundings. In this study, a dynamic rooting scheme describing root growth as a compromise between water and nitrogen availability in the subsurface was incorporated into the Community Earth System Model 1.2.0 (CESM1.2.0. The dynamic rooting scheme was incorporated to investigate the effects of land–atmosphere carbon and water fluxes, and their subsequent influences on climate. The modeling results of global land–atmosphere coupling simulations from 1982 to 2005 show that the dynamic rooting scheme can improve gross primary production (GPP and evapotranspiration (ET in most tropical regions, and in some high-latitude regions with lower mean biases (MBEs and root mean square errors (RMSEs. Obvious differences in 2-m air temperature were found in low-latitude areas, with decreases of up to 2 °C. Under the influence of local land-surface feedback and large-scale moisture advection, total precipitation in the northeastern area of the Amazon and the west coast of Africa increased by 200 mm year−1, and that of South America, central Africa, and Indonesia increased by 50 to 100 mm year−1. Overall, the model incorporating the dynamic rooting scheme may reveal cooling and humidifying effects, especially for tropical regions.

  18. Ambient ultraviolet radiation in the Arctic reduces root biomass and alters microbial community composition but has no effects on microbial biomass

    DEFF Research Database (Denmark)

    Rinnan, R.; Keinänen, M.M.; Kasurinen, A.

    2005-01-01

    We assessed the effects of ambient solar ultraviolet (UV) radiation on below-ground parameters in an arctic heath in north-eastern Greenland. We hypothesized that the current UV fluxes would reduce root biomass and mycorrhizal colonization and that these changes would lead to lower soil microbial...... biomass and altered microbial community composition. These hypotheses were tested on cored soil samples from a UV reduction experiment with three filter treatments (Mylar, 60% UV-B reduction; Lexan, up to 90% UV-B reduction+UV-A reduction; UV transparent Teflon, filter control) and an open control...... treatment in two study sites after 3 years' manipulation. Reduction of both UV-A and UV-B radiation caused over 30% increase in the root biomass of Vaccinium uliginosum, which was the dominant plant species. UV reduction had contrasting effects on ericoid mycorrhizal colonization of V. uliginosum roots...

  19. [Effects of litter and root exclusion on soil microbial community composition and function of four plantations in subtropical sandy coastal plain area, China].

    Science.gov (United States)

    Sang, Chang Peng; Wan, Xiao Hua; Yu, Zai Peng; Wang, Min Huang; Lin, Yu; Huang, Zhi Qun

    2017-04-18

    We conducted detritus input and removal treatment (DIRT) to examine the effects of shifting above- and belowground carbon (C) inputs on soil microbial biomass, community composition and function in subtropical Pinus elliottii, Eucalyptus urophylla × Eucalyptus grandis, Acacia aulacocarpa and Casuarina equisetifolia coastal sandy plain forests, and the treatments included: root trenching, litter removal and control. Up to September 2015, one year after the experiment began, we collected the 0-10 cm soil samples from each plot. Phospholipid fatty acid (PLFA) analysis was used to characterize the microbial community composition, and micro-hole enzymatic detection technology was utilized to determine the activity of six kinds of soil enzymes. Results showed that changes in microbial biomass induced by the C input manipulations differed among tree species, and mainly affected by litter and root qualily. In E. urophylla × E. grandis stands, root trenching significantly decreased the contents of total PLFAs, Gram-positive bacteria, Gram-negative bacteria, fungi and actinomycetes by 31%, 30%, 32%, 36% and 26%, respectively. Litter removal reduced the contents of Gram-positive bacteria, fungi and actinomycetes by 24%, 27% and 24%, respectively. However, C input manipulations had no significant effect on soil microbial biomassunder other three plantations. According to the effect of C input manipulations on soil microbial community structure, litter and root exclusion decreased fungi abundance and increased actinomycetes abundance. Different treatments under different plantations resulted in various soil enzyme activities. Litter removal significantly decreased the activities of cellobiohydrolase, β-glucosidase, acid phosphatase and N-acetyl-β-d-glucosaminidase of P. elliottii, A. aulacocarpa and C. equisetifolia, root exclusion only decreased and increased the activities of β-glucosidase in P. elliottii and A. aulacocarpa forest soils, respectively. Litter removal also

  20. Root development during soil genesis: effects of root-root interactions, mycorrhizae, and substrate

    Science.gov (United States)

    Salinas, A.; Zaharescu, D. G.

    2015-12-01

    A major driver of soil formation is the colonization and transformation of rock by plants and associated microbiota. In turn, substrate chemical composition can also influence the capacity for plant colonization and development. In order to better define these relationships, a mesocosm study was set up to analyze the effect mycorrhizal fungi, plant density and rock have on root development, and to determine the effect of root morphology on weathering and soil formation. We hypothesized that plant-plant and plant-fungi interactions have a stronger influence on root architecture and rock weathering than the substrate composition alone. Buffalo grass (Bouteloua dactyloides) was grown in a controlled environment in columns filled with either granular granite, schist, rhyolite or basalt. Each substrate was given two different treatments, including grass-microbes and grass-microbes-mycorrhizae and incubated for 120, 240, and 480 days. Columns were then extracted and analyzed for root morphology, fine fraction, and pore water major element content. Preliminary results showed that plants produced more biomass in rhyolite, followed by schist, basalt, and granite, indicating that substrate composition is an important driver of root development. In support of our hypothesis, mycorrhizae was a strong driver of root development by stimulating length growth, biomass production, and branching. However, average root length and branching also appeared to decrease in response to high plant density, though this trend was only present among roots with mycorrhizal fungi. Interestingly, fine fraction production was negatively correlated with average root thickness and volume. There is also slight evidence indicating that fine fraction production is more related to substrate composition than root morphology, though this data needs to be further analyzed. Our hope is that the results of this study can one day be applied to agricultural research in order to promote the production of crops

  1. The cultivation bias: different communities of arbuscular mycorrhizal fungi detected in roots from the field, from bait plants transplanted to the field, and from a greenhouse trap experiment.

    Science.gov (United States)

    Sýkorová, Zuzana; Ineichen, Kurt; Wiemken, Andres; Redecker, Dirk

    2007-12-01

    The community composition of arbuscular mycorrhizal fungi (AMF) was investigated in roots of four different plant species (Inula salicina, Medicago sativa, Origanum vulgare, and Bromus erectus) sampled in (1) a plant species-rich calcareous grassland, (2) a bait plant bioassay conducted directly in that grassland, and (3) a greenhouse trap experiment using soil and a transplanted whole plant from that grassland as inoculum. Roots were analyzed by AMF-specific nested polymerase chain reaction, restriction fragment length polymorphism screening, and sequence analyses of rDNA small subunit and internal transcribed spacer regions. The AMF sequences were analyzed phylogenetically and used to define monophyletic phylotypes. Overall, 16 phylotypes from several lineages of AMF were detected. The community composition was strongly influenced by the experimental approach, with additional influence of cultivation duration, substrate, and host plant species in some experiments. Some fungal phylotypes, e.g., GLOM-A3 (Glomus mosseae) and several members of Glomus group B, appeared predominantly in the greenhouse experiment or in bait plants. Thus, these phylotypes can be considered r strategists, rapidly colonizing uncolonized ruderal habitats in early successional stages of the fungal community. In the greenhouse experiment, for instance, G. mosseae was abundant after 3 months, but could not be detected anymore after 10 months. In contrast, other phylotypes as GLOM-A17 (G. badium) and GLOM-A16 were detected almost exclusively in roots sampled from plants naturally growing in the grassland or from bait plants exposed in the field, indicating that they preferentially occur in late successional stages of fungal communities and thus represent the K strategy. The only phylotype found with high frequency in all three experimental approaches was GLOM A-1 (G. intraradices), which is known to be a generalist. These results indicate that, in greenhouse trap experiments, it is difficult

  2. HIV/AIDS, beersellers and critical community health psychology in Cambodia: a case study.

    Science.gov (United States)

    Lubek, Ian; Lee, Helen; Kros, Sarath; Wong, Mee Lian; Van Merode, Tiny; Liu, James; McCreanor, Tim; Idema, Roel; Campbell, Catherine

    2014-01-01

    This case study illustrates a participatory framework for confronting critical community health issues using 'grass-roots' research-guided community-defined interventions. Ongoing work in Cambodia has culturally adapted research, theory and practice for particular, local health-promotion responses to HIV/AIDS, alcohol abuse and other challenges in the community of Siem Reap. For resource-poor communities in Cambodia, we recycle such 'older' concepts as 'empowerment' and 'action research'. We re-imagine community health psychology, when confronted with 'critical', life-and-death issues, as adjusting its research and practices to local, particular ontological and epistemological urgencies of trauma, morbidity and mortality.

  3. Root rots

    Science.gov (United States)

    Kathryn Robbins; Philip M. Wargo

    1989-01-01

    Root rots of central hardwoods are diseases caused by fungi that infect and decay woody roots and sometimes also invade the butt portion of the tree. By killing and decaying roots, root rotting fungi reduce growth, decrease tree vigor, and cause windthrow and death. The most common root diseases of central hardwoods are Armillaria root rot, lnonotus root rot, and...

  4. Effect of root exudates of various plants on composition of bacteria and fungi communities with special regard to pathogenic soil-borne fungi

    OpenAIRE

    Danuta Piętka; Elżbieta Patkowska

    2013-01-01

    The purpose of the studies conducted in the years 1996 - 1998 was to determine the composition of bacteria and fungi populations in the rhizosphere of winter wheat, spring wheat, soybean and potato, and in non-rhizosphere soil. Besides, the effect of root exudates of these plants on the formation of pathogenic fungi communities was established. The microbiological analysis showed that the greatest tolal number of bacteria was found in the rhizospheres of potato and soybean, and the lowest num...

  5. Ecophysiological responses of native and invasive grasses to simulated warming and drought

    Science.gov (United States)

    Ravi, S.; Law, D. J.; Wiede, A.; Barron-Gafford, G. A.; Breshears, D. D.; Dontsova, K.; Huxman, T. E.

    2011-12-01

    Climate models predict that many arid regions around the world - including the North American deserts - may become affected more frequently by recurrent droughts. At the same time, these regions are experiencing rapid vegetation transformations such as invasion by exotic grasses. Thus, understanding the ecophysiological processes accompanying exotic grass invasion in the context of rising temperatures and recurrent droughts is fundamental to global change research. Under ambient and warmer (+ 4° C) conditions inside the Biosphere 2 facility, we compared the ecophysiological responses (e.g. photosynthesis, stomatal conductance, pre-dawn leaf water potential, light & CO2 response functions, biomass) of a native grass - Heteropogan contortus (Tangle head) and an invasive grass - Pennisetum ciliare (Buffel grass) growing in single and mixed communities. Further, we monitored the physiological responses and mortality of these plant communities under moisture stress conditions, simulating a global change-type-drought. The results indicate that the predicted warming scenarios may enhance the invasibility of desert landscapes by exotic grasses. In this study, buffel grass assimilated more CO2 per unit leaf area and out-competed native grasses more efficiently in a warmer environment. However, scenarios involving a combination of drought and warming proved disastrous to both the native and invasive grasses, with drought-induced grass mortality occurring at much shorter time scales under warmer conditions.

  6. Diversity of alkane hydroxylase genes on the rhizoplane of grasses planted in petroleum-contaminated soils

    OpenAIRE

    Tsuboi, Shun; Yamamura, Shigeki; Nakajima-Kambe, Toshiaki; Iwasaki, Kazuhiro

    2015-01-01

    The study investigated the diversity and genotypic features of alkane hydroxylase genes on rhizoplanes of grasses planted in artificial petroleum-contaminated soils to acquire new insights into the bacterial communities responsible for petroleum degradation in phytoremediation. Four types of grass (Cynodon dactylon, two phenotypes of Zoysia japonica, and Z. matrella) were used. The concentrations of total petroleum hydrocarbon effectively decreased in the grass-planted systems compared with t...

  7. A study of the wet deposit and foliar uptake of iodine and strontium on rye-grass and clover

    International Nuclear Information System (INIS)

    Angeletti, Livio; Levi, Emilio; Commission of the European Communities, Ispra

    1977-12-01

    Foliar uptake of iodine and strontium by rye-grass and clover was studied as a function of aspersion intensities. At the same time, the contribution of root sorption to foliar uptake was measured. The effective half-lives of radionuclides of standing and harvested grass were also determined together with their uptake under the action of demineralized water aspersion [fr

  8. Comparison of phytoremediation potential of three grass species in soil contaminated with cadmium

    Directory of Open Access Journals (Sweden)

    Gołda Sylwia

    2016-03-01

    Full Text Available The aim of the study was to compare the toleration of Poa pratensis, Lolium perenne and Festuca rubra to cadmium contamination as well as the phytoremediation potential of these three species of grass. The pot experiment was conducted in four replications in pots containing 2.0 kg of soil. The soil was contaminated with three doses of Cd – 30, 60 and 120 mg·kg−1. After two months, the aerial parts of plants were harvested. The roots were dug up, brushed off from the remaining soil and washed with water. The biomass was defined and the cadmium concentration was determined in aerial parts and roots. The phytoremediation potential of grasses was evaluated using biomass of grasses, bioaccumulation factor (BF and translocation factor (TF. All three tested species of grasses had TF 1. It indicates their suitability for phytostabilisation and makes them unsuitable for phytoextraction of Cd from the soil. Comparing the usefulness of the tested grasses for phytoremediation has shown that the phytostabilisation potential of P. pratensis was lower than that of L. perenne and F. rubra. P. pratensis was distinguished by higher TF, smaller root biomass and lower tolerance for Cd excess in the soil in comparison with the two other test grasses. At the same time, L. perenne was characterised by the smallest decrease in biomass and the largest Cd accumulation in roots at the lowest dose of Cd. It indicates good usefulness for phytostabilisation of soils characterised by a relatively small pollution by cadmium.

  9. Invasive Andropogon gayanus (gamba grass) is an ecosystem transformer of nitrogen relations in Australian savanna.

    Science.gov (United States)

    Rossiter-Rachor, N A; Setterfield, S A; Douglas, M M; Hutley, L B; Cook, G D; Schmidt, S

    2009-09-01

    Invasion by the African grass Andropogon gayanus is drastically altering the understory structure of oligotrophic savannas in tropical Australia. We compared nitrogen (N) relations and phenology of A. gayanus and native grasses to examine the impact of invasion on N cycling and to determine possible reasons for invasiveness of A. gayanus. Andropogon gayanus produced up to 10 and four times more shoot phytomass and root biomass, with up to seven and 2.5 times greater shoot and root N pools than native grass understory. These pronounced differences in phytomass and N pools between A. gayanus and native grasses were associated with an altered N cycle. Most growth occurs in the wet season when, compared with native grasses, dominance of A. gayanus was associated with significantly lower total soil N pools, lower nitrification rates, up to three times lower soil nitrate availability, and up to three times higher soil ammonium availability. Uptake kinetics for different N sources were studied with excised roots of three grass species ex situ. Excised roots of A. gayanus had an over six times higher-uptake rate of ammonium than roots of native grasses, while native grass Eriachne triseta had a three times higher uptake rate of nitrate than A. gayanus. We hypothesize that A. gayanus stimulates ammonification but inhibits nitrification, as was shown to occur in its native range in Africa, and that this modification of the soil N cycle is linked to the species' preference for ammonium as an N source. This mechanism could result in altered soil N relations and could enhance the competitive superiority and persistence of A. gayanus in Australian savannas.

  10. Meadow-grass gall midge

    DEFF Research Database (Denmark)

    Hansen, Lars Monrad

    The area with meadow-grass (Poa pratensis, L.) grown for seed production in Den-mark is a significant proportion of the entire seed production. The meadow-grass gall midge (Mayetiola schoberi, Barnes 1958) is of considerable economic importance since powerful attacks can reduce the yield...

  11. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities

    OpenAIRE

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2017-01-01

    Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phyto...

  12. Designing hybrid grass genomes to control runoff generation

    Science.gov (United States)

    MacLeod, C.; Binley, A.; Humphreys, M.; King, I. P.; O'Donovan, S.; Papadopoulos, A.; Turner, L. B.; Watts, C.; Whalley, W. R.; Haygarth, P.

    2010-12-01

    Sustainable management of water in landscapes requires balancing demands of agricultural production whilst moderating downstream effects like flooding. Pasture comprises 69% of global agricultural areas and is essential for producing food and fibre alongside environmental goods and services. Thus there is a need to breed forage grasses that deliver multiple benefits through increased levels of productivity whilst moderating fluxes of water. Here we show that a novel grass hybrid that combines the entire genomes of perennial ryegrass (Lolium perenne - the grass of choice for Europe’s forage agriculture) and meadow fescue (Festuca pratensis) has a significant role in flood prevention. Field plot experiments established differences in runoff generation with the hybrid cultivar reducing runoff by 50% compared to perennial ryegrass cultivar, and by 35% compared to a meadow fescue cultivar (34 events over two years, replicated randomized-block design, statistically significant differences). This important research outcome was the result of a project that combined plant genetics, soil physics and plot scale hydrology to identify novel grass genotypes that can reduce runoff from grassland systems. Through a coordinated series of experiments examining effects from the gene to plot scale, we have identified that the rapid growth and then turnover of roots in the L. perenne x F. pratensis hybrid is likely to be a key mechanism in reducing runoff generation. More broadly this is an exciting first step to realizing the potential to design grass genomes to achieve both food production, and to deliver flood control, a key ecosystem service.

  13. Enhanced precipitation variability decreases grass- and increases shrub-productivity

    Science.gov (United States)

    Gherardi, Laureano A.; Sala, Osvaldo E.

    2015-01-01

    Although projections of precipitation change indicate increases in variability, most studies of impacts of climate change on ecosystems focused on effects of changes in amount of precipitation, overlooking precipitation variability effects, especially at the interannual scale. Here, we present results from a 6-y field experiment, where we applied sequences of wet and dry years, increasing interannual precipitation coefficient of variation while maintaining a precipitation amount constant. Increased precipitation variability significantly reduced ecosystem primary production. Dominant plant-functional types showed opposite responses: perennial-grass productivity decreased by 81%, whereas shrub productivity increased by 67%. This pattern was explained by different nonlinear responses to precipitation. Grass productivity presented a saturating response to precipitation where dry years had a larger negative effect than the positive effects of wet years. In contrast, shrubs showed an increasing response to precipitation that resulted in an increase in average productivity with increasing precipitation variability. In addition, the effects of precipitation variation increased through time. We argue that the differential responses of grasses and shrubs to precipitation variability and the amplification of this phenomenon through time result from contrasting root distributions of grasses and shrubs and competitive interactions among plant types, confirmed by structural equation analysis. Under drought conditions, grasses reduce their abundance and their ability to absorb water that then is transferred to deep soil layers that are exclusively explored by shrubs. Our work addresses an understudied dimension of climate change that might lead to widespread shrub encroachment reducing the provisioning of ecosystem services to society. PMID:26417095

  14. Proliferação e enraizamento in vitro de brotos de palma forrageira - Opuntia ficus-indica (L. MILL - DOI: 10.4025/actascibiolsci.v26i2.1641 Proliferation and rooting in vitro of buds of palm grass Opuntia ficusindica (L. MILL - DOI: 10.4025/actascibiolsci.v26i2.1641

    Directory of Open Access Journals (Sweden)

    Francisco de Assis Paiva Campos

    2004-04-01

    Full Text Available O trabalho foi conduzido no Departamento de Bioquímica e Biologia Molecular da Universidade Federal do Ceará com o objetivo de avaliar o efeito do 6- benzilaminopurina (BAP e do ácido indolacético (AIA na proliferação e no enraizamento in vitro de brotos da palma forrageira. Os explantes foram incubados no meio de cultura com sais e vitaminas MS, suplementados com 5% de sacarose, 0,8% de ágar e pH 5,85. Para a proliferação, os brotos foram inoculados em placas de Petri contendo o meio de cultura em diferentes concentrações de BAP. O delineamento experimental foi inteiramente ao acaso, em arranjo fatorial de 10 x 3, com 3 repetições. No enraizamento, os brotos foram inoculados no meio de cultura contendo diferentes concentrações de AIA. O delineamento experimental foi inteiramente ao acaso, em arranjo fatorial de 10 x 3, com 3 repetições. Concluiu-se que os melhores protocolos para a proliferação e o enraizamento de brotos foram, respectivamente, BAP 1,00mg/L e AIA 5,00mg/LThe work was carried out in the Biochemistry and Molecular Biology Department of Ceará Federal University. The aim was to evaluate the effects of 6- benzylaminopurine (BAP and indolacetic acid (IAA on proliferation and rooting ,em>in vitro of buds of palm grass. The samples were incubated in the culture environment with salts, vitamins MS, 5% of sucrose, 0.8% of agar and pH of 5.85. For the proliferation, the buds were inoculated in Petri plates, and the culture environment was contained in different BAP concentrations. The experimental delineation was entirely randomly in an arrangement factorial of 10 x 3 and three replications. In the rooting, the buds were inoculated in the culture environment and they had different concentrations of indoacetic acid (IAA. Results showed that the best protocols for proliferation and buds of rooting were, respectively: BAP to 1.00mg/L and IAA to 5.00mg/L

  15. Extending juvenility in grasses

    Energy Technology Data Exchange (ETDEWEB)

    Kaeppler, Shawn; de Leon Gatti, Natalia; Foerster, Jillian

    2017-04-11

    The present invention relates to compositions and methods for modulating the juvenile to adult developmental growth transition in plants, such as grasses (e.g. maize). In particular, the invention provides methods for enhancing agronomic properties in plants by modulating expression of GRMZM2G362718, GRMZM2G096016, or homologs thereof. Modulation of expression of one or more additional genes which affect juvenile to adult developmental growth transition such as Glossy15 or Cg1, in conjunction with such modulation of expression is also contemplated. Nucleic acid constructs for down-regulation of GRMZM2G362718 and/or GRMZM2G096016 are also contemplated, as are transgenic plants and products produced there from, that demonstrate altered, such as extended juvenile growth, and display associated phenotypes such as enhanced yield, improved digestibility, and increased disease resistance. Plants described herein may be used, for example, as improved forage or feed crops or in biofuel production.

  16. Evaluating poverty grass (Danthonia spicata) for golf courses in the Midwest

    Science.gov (United States)

    Nadia E. Navarrete-Tindall; J.W. Van Sambeek

    2010-01-01

    Poverty grass (Danthonia spicata (L.) P. beauv. Ex Roem & Schult. ) results presented here are part of ongoing studies to evaluate its adaptation for golf courses as part of low maintenance natural communities at Lincoln University of Missouri. Because its natural adaptation to shade and poor soils, poverty grass could be established in golf...

  17. Thermally treated grass fibers as colonizable substrate for beneficial bacterial inoculum

    NARCIS (Netherlands)

    Trifonova, R.D.; Postma, J.; Ketelaars, J.J.M.H.; Elsas, van J.D.

    2008-01-01

    This study investigates how thermally treated (i.e., torrefied) grass, a new prospective ingredient of potting soils, is colonized by microorganisms. Torrefied grass fibers (TGF) represent a specific colonizable niche, which is potentially useful to establish a beneficial microbial community that

  18. Phytostabilisation potential of lemon grass (Cymbopogon flexuosus (Nees ex Stend) Wats) on iron ore tailings.

    Science.gov (United States)

    Mohanty, M; Dhal, N K; Patra, P; Das, B; Reddy, P S R

    2012-01-01

    The present pot culture study was carried out for the potential phytostabilisation of iron ore tailings using lemon grass (Cymbopogon flexuosus) a drought tolerant, perennial, aromatic grass. Experiments have been conducted by varying the composition of garden soil (control) with iron ore tailings. The various parameters, viz. growth of plants, number of tillers, biomass and oil content of lemon grass are evaluated. The studies have indicated that growth parameters of lemon grass in 1:1 composition of garden soil and iron ore tailings are significantly more (-5% increase) compared to plants grown in control soil. However, the oil content of lemon grass in both the cases more or less remained same. The results also infer that at higher proportion of tailings the yield of biomass decreases. The studies indicate that lemongrass with its fibrous root system is proved to be an efficient soil binder by preventing soil erosion.

  19. Engaging community to support HIV prevention research.

    Science.gov (United States)

    Sahay, Seema; Mehendale, Sanjay

    2011-01-01

    Actively engaging communities in effective partnerships is considered critical for ethically robust and locally relevant HIV prevention research. This can be challenging in developing countries that have little prior experience in this area. This paper summarizes processes and lessons learnt while setting up the Community Involvement Plan of National AIDS Research Institute, Pune, India. Formal partnerships were established with voluntary agencies. The focus was on using strategies adapted from participatory learning and action techniques. The community program was implemented through peer educators specifically identified from the communities where partner non-governmental organizations function. At the grass root level, peer educators imparted education to the common people about research studies and helped to implement community based recruitment and retention activities. The focus was on facilitating periodic interaction between the outreach workers of the research team and the peers and modifying the strategies till they were found locally implementable and appropriate. Through adequate time investment, mutually beneficial and respectful partnerships with community based organizations and grass root level workers, the community became actively involved in clinical research. The program helped in developing a sense of partnership among the peers for the research conducted by the research organization, widening the net of community education and identification of research participants. By building trust in the community and implementing research within an ethical framework, culturally sensitive matters were appropriately addressed. The community involvement process is long, laborious and ever-evolving. Effective community engagement requires institutional leadership support, adequate funding and commitment by researchers. It is possible to sustain such a model in a resource limited setting.

  20. Comparative Evaluation of Anaerobic Bacterial Communities Associated with Roots of Submerged Macrophytes Growing in Marine or Brackish Water Sediments

    Science.gov (United States)

    Sediment microbial communities are important for seagrass growth and carbon cycling, however relatively few studies have addressed the composition of prokaryotic communities in seagrass bed sediments. Selective media were used enumerate culturable anaerobic bacteria associated ...

  1. Changes in root-associated microbial communities are determined by species-specific plant growth responses to stress and disturbance

    Czech Academy of Sciences Publication Activity Database

    Bouasria, A.; Mustafa, T.; de Bello, Francesco; Zinger, L.; Lemperiere, G.; Geremia, R. A.; Choler, P.

    2012-01-01

    Roč. 52, Sep-Oct 2012 (2012), s. 59-66 ISSN 1164-5563 Institutional support: RVO:67985939 Keywords : ecosystem function * bacterial communities * grassland communities Subject RIV: EF - Botanics Impact factor: 1.838, year: 2012

  2. Responses of three grass species to creosote during phytoremediation

    International Nuclear Information System (INIS)

    Huang Xiaodong; El-Alawi, Yousef; Penrose, Donna M.; Glick, Bernard R.; Greenberg, Bruce M.

    2004-01-01

    Phytoremediation of creosote-contaminated soil was monitored in the presence of Tall fescue, Kentucky blue grass, or Wild rye. For all three grass species, plant growth promoting rhizobacteria (PGPR) were evaluated for plant growth promotion and protection of plants from contaminant toxicity. A number of parameters were monitored including plant tissue water content, root growth, plant chlorophyll content and the chlorophyll a/b ratio. The observed physiological data indicate that some plants mitigated the toxic effects of contaminants. In addition, in agreement with our previous experiments reported in the accompanying paper (Huang, X.-D., El-Alawi, Y., Penrose, D.M., Glick, B.R., Greenberg, B.M., 2004. A multi-process phytoremediation system for removal of polycyclic aromatic hydrocarbons from contaminated soil. Environ. Poll. doi: 10.1016/j.envpol.2003.09.031), PGPR were able to greatly enhance phytoremediation. PGPR accelerated plant growth, especially roots, in heavily contaminated soils, diminishing the toxic effects of contaminants to plants. Thus, the increased root biomass in PGPR-treated plants led to more effective remediation. - Plant growth promoting rhizobacteria enhanced growth and remediation of three grass species

  3. Production of tropical forage grasses under different shading levels

    Directory of Open Access Journals (Sweden)

    Francisco Eduardo Torres

    2017-12-01

    Full Text Available This study aimed to evaluate the forage production of three tropical forage grasses under different shading levels. The experiment was conducted in a greenhouse at Universidade Estadual de Mato Grosso do Sul, University Unit of Aquidauana (UEMS/UUA, in a soil classified as Ultisol sandy loam texture. The treatments consisted of three grasses species combinations (B. brizantha cv. Marandu, B. decumbens cv. Basilisck and Panicum maximum cv. Tanzania, submitted to four shading levels (0, 30, 50 and 75%, arranged in a completely randomized blocks design in a factorial 3 x 4, with eight replications. After harvest, the plants were separated into shoot and roots for determination of shoot fresh mass (SFM, shoot dry mass (SDM and roots dry mass production. After analysis of variance, the qualitative factor was subjected to comparison of averages by Tukey’s test, and the quantitative factor to analysis of polynomial regression, being interactions appropriately unfolded. It was verified that B. decumbens, by its linearly increasing production of forage and less decrease of root formation, is the most recommended for shading conditions compared to grasses Tanzania and Marandu.

  4. Dynamic model for the transfer of CS-137 through the soil-grass-lamb foodchain

    DEFF Research Database (Denmark)

    Nielsen, S.P.

    1994-01-01

    A dynamic radioecological model for the transfer of radiocaesium through the soil-grass-lamb foodchain was constructed on the basis of field data collected in 1990–1993 from the Nordic countries: Denmark, Faroe Islands, Finland, Iceland, Norway and Sweden. The model assumes an initial soil...... contamination of one kilobecquerel of 137Cs per square metre and simulates the transfer to grass through root uptake in addition to direct contamination from resuspended activity. The model covers two different soil types: clay-loam and organic, with significantly different transfers of radiocaesium to grass...

  5. Accelerated development in Johnsongrass seedlings (Sorghum halepense suppresses the growth of native grasses through size-asymmetric competition.

    Directory of Open Access Journals (Sweden)

    Susanne Schwinning

    Full Text Available Invasive plant species often dominate native species in competition, augmenting other potential advantages such as release from natural enemies. Resource pre-emption may be a particularly important mechanism for establishing dominance over competitors of the same functional type. We hypothesized that competitive success of an exotic grass against native grasses is mediated by establishing an early size advantage. We tested this prediction among four perennial C4 warm-season grasses: the exotic weed Johnsongrass (Sorghum halepense, big bluestem (Andropogon gerardii, little bluestem (Schizachyrium scoparius and switchgrass (Panicum virgatum. We predicted that a the competitive effect of Johnsongrass on target species would be proportional to their initial biomass difference, b competitive effect and response would be negatively correlated and c soil fertility would have little effect on competitive relationships. In a greenhouse, plants of the four species were grown from seed either alone or with one Johnsongrass neighbor at two fertilizer levels and periodically harvested. The first two hypotheses were supported: The seedling biomass of single plants at first harvest (50 days after seeding ranked the same way as the competitive effect of Johnsongrass on target species: Johnsongrass < big bluestem < little bluestem/switchgrass, while Johnsongrass responded more strongly to competition from Johnsongrass than from native species. At final harvest, native plants growing with Johnsongrass attained between 2-5% of their single-plant non-root biomass, while Johnsongrass growing with native species attained 89% of single-plant non-root biomass. Fertilization enhanced Johnsongrass' competitive effects on native species, but added little to the already severe competitive suppression. Accelerated early growth of Johnsongrass seedlings relative to native seedlings appeared to enable subsequent resource pre-emption. Size-asymmetric competition and resource

  6. Trace metals bioaccumulation potentials of three indigenous grasses grown on polluted soils collected around mining areas in Pretoria, South Africa

    International Nuclear Information System (INIS)

    Lion, G. N.; Olowoyo, J. O.; Modise, T. A.

    2016-01-01

    The rapid increase in the number of industries may have increased the levels of trace metals in the soil. Phyto remediation of these polluted soils using indigenous grasses is now considered an alternative method in re mediating these polluted soils. The present study investigated and compared the ability of three indigenous grasses as bioaccumulators of trace metals from polluted soils. Seeds of these grasses were introduced into pots containing polluted soil samples after the addition of organic manure. The seeds of the grasses were allowed to germinate and grow to maturity before harvesting. The harvested grasses were later separated into shoots and roots and the trace metal contents were determined using ICP –MS. From all the grasses, the concentrations of trace metals in the roots were more than those recorded in the shoot with a significant difference (P Themeda trianda > Cynodon dactylon. The study concluded that the three grasses used were all able to bioaccumulate trace metals in a similar proportion from the polluted soils. However, since livestock feed on these grasses, they should not be allowed to feed on the grasses used in this study especially when harvested from a polluted soil due to their bioaccumulative potentials. (au)

  7. Short Communication: Autelogical studies on grass species in ...

    African Journals Online (AJOL)

    A literature survey of autecological studies on southern African grass species was undertaken. Results revealed that there is a comparative lack of autecological versus community studies. Where autecological studies have been conducted, most of the attention was focused on 'pasture' or 'desirable' species with ...

  8. DESIGN OF GRASS BRIQUETTE MACHINE

    African Journals Online (AJOL)

    user

    E-mail addresses: 1 mike.ajieh@gmail.com, 2 dracigboanugo@yahoo.com, ... machine design was considered for processing biomass of grass origin. The machine operations include pulverization, compaction and extrusion of the briquettes.

  9. Breeding for Grass Seed Yield

    DEFF Research Database (Denmark)

    Boelt, Birte; Studer, Bruno

    2010-01-01

    Seed yield is a trait of major interest for many fodder and amenity grass species and has received increasing attention since seed multiplication is economically relevant for novel grass cultivars to compete in the commercial market. Although seed yield is a complex trait and affected...... by agricultural practices as well as environmental factors, traits related to seed production reveal considerable genetic variation, prerequisite for improvement by direct or indirect selection. This chapter first reports on the biological and physiological basics of the grass reproduction system, then highlights...... important aspects and components affecting the seed yield potential and the agronomic and environmental aspects affecting the utilization and realization of the seed yield potential. Finally, it discusses the potential of plant breeding to sustainably improve total seed yield in fodder and amenity grasses....

  10. Grass and weed killer poisoning

    Science.gov (United States)

    ... medlineplus.gov/ency/article/002838.htm Grass and weed killer poisoning To use the sharing features on this page, please enable JavaScript. Many weed killers contain dangerous chemicals that are harmful if ...

  11. Nitrogen-fixing bacteria in Mediterranean seagrass (Posidonia oceanica) roots

    KAUST Repository

    Garcias Bonet, Neus

    2016-03-09

    Biological nitrogen fixation by diazotrophic bacteria in seagrass rhizosphere and leaf epiphytic community is an important source of nitrogen required for plant growth. However, the presence of endophytic diazotrophs remains unclear in seagrass tissues. Here, we assess the presence, diversity and taxonomy of nitrogen-fixing bacteria within surface-sterilized roots of Posidonia oceanica. Moreover, we analyze the nitrogen isotopic signature of seagrass tissues in order to notice atmospheric nitrogen fixation. We detected nitrogen-fixing bacteria by nifH gene amplification in 13 out of the 78 roots sampled, corresponding to 9 locations out of 26 meadows. We detected two different types of bacterial nifH sequences associated with P. oceanica roots, which were closely related to sequences previously isolated from the rhizosphere of a salt marsh cord grass and a putative anaerobe. Nitrogen content of seagrass tissues showed low isotopic signatures in all the sampled meadows, pointing out the atmospheric origin of the assimilated nitrogen by seagrasses. However, this was not related with the presence of endophytic nitrogen fixers, suggesting the nitrogen fixation occurring in rhizosphere and in the epiphytic community could be an important source of nitrogen for P. oceanica. The low diversity of nitrogen-fixing bacteria reported here suggests species-specific relationships between diazotrophs and P. oceanica, revealing possible symbiotic interactions that could play a major role in nitrogen acquisition by seagrasses in oligotrophic environments where they form lush meadows.

  12. High green fodder yielding new grass varieties

    OpenAIRE

    C. Babu, K. Iyanar and A. Kalamani

    2014-01-01

    Two high biomass yielding forage grass varieties one each in Cumbu Napier hybrid and Guinea grass have been evolved at the Department of Forage Crops, Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore and identified for release at national (All India) level as Cumbu Napier hybrid grass CO (BN) 5 and Guinea grass CO (GG) 3 during 2012 and 2013 respectively. Cumbu Napier hybrid grass CO (BN) 5 secured first rank at all national level with reference to green ...

  13. Rooting depths of plants on low-level waste disposal sites

    International Nuclear Information System (INIS)

    Foxx, T.S.; Tierney, G.D.; Williams, J.M.

    1984-11-01

    In 1981-1982 an extensive bibliographic study was done to reference rooting depths of native plants in the United States. The data base presently contains 1034 different rooting citations with approximately 12,000 data elements. For this report, data were analyzed for rooting depths related to species found on low-level waste (LLW) sites at Los Alamos National Laboratory. Average rooting depth and rooting frequencies were determined and related to present LLW maintenance. The data base was searched for information on rooting depths of 53 species found on LLW sites at Los Alamos National Laboratory. The study indicates 12 out of 13 grasses found on LLW sites root below 91 cm. June grass [Koeleria cristata (L.) Pers.] (76 cm) was the shallowest rooting grass and side-oats grama [Bouteloua curtipendula (Michx.) Torr.] was the deepest rooting grass (396 cm). Forbs were more variable in rooting depths. Indian paintbrush (Castelleja spp.) (30 cm) was the shallowest rooting forb and alfalfa (Medicago sativa L.) was the deepest (>3900 cm). Trees and shrubs commonly rooted below 457 cm. The shallowest rooting tree was elm (Ulmus pumila L.) (127 cm) and the deepest was one-seed juniper [Juniperus monosperma (Engelm) Sarg.] (>6000 cm). Apache plume [Fallugia paradoxa (D. Don) Endl.] rooted to 140 cm, whereas fourwing saltbush [Atriplex canecens (Pursh) Nutt.] rooted to 762 cm

  14. Climate change and the invasion of California by grasses

    DEFF Research Database (Denmark)

    Sandel, Brody Steven; Dangremond, Emily

    2012-01-01

    Over the next century, changes in the global climate are expected to have major consequences for plant communities, possibly including the exacerbation of species invasions. We evaluated this possibility in the grass flora of California, which is economically and ecologically important and heavily...... invaded. We used a novel, trait-based approach involving two components: identifying differences in trait composition between native and exotic components of the grass flora and evaluating contemporary trait–climate relationships across the state. The combination of trait–climate relationships and trait...

  15. Effects of urban grass coverage on rainfall-induced runoff in Xi'an loess region in China

    Directory of Open Access Journals (Sweden)

    Jing Li

    2017-10-01

    Full Text Available In this study, laboratory rainfall simulation experiments were conducted to investigate the regulatory effects of grass coverage on rainfall-runoff processes. A total of 80 grass blocks planted with well-grown manilagrass, together with their root systems, were sampled from an eastern suburban area of Xi'an City in the northwest arid area of China and sent to a laboratory for rainfall simulation experiments. The runoff and infiltration processes of a slope with different grass coverage ratios and vegetation patterns were analyzed. The results show that the runoff coefficient decreases with the increase of the grass coverage ratio, and the influence of grass coverage on the reduction of runoff shows a high degree of spatial variation. At a constant grass coverage ratio, as the area of grass coverage moves downward, the runoff coefficient, total runoff, and flood peak discharge gradually decrease, and the flood peak occurs later. With the increase of the grass coverage ratio, the flood peak discharge gradually decreases, and the flood peak occurs later as well. In conclusion, a high grass coverage ratio with the area of grass coverage located at the lower part of the slope will lead to satisfactory regulatory effects on rainfall-induced runoff.

  16. Root-associated fungal communities along a primary succession on a mine spoil: Distinct ecological guilds assemble differently

    Czech Academy of Sciences Publication Activity Database

    Kolaříková, Z.; Kohout, Petr; Krüger, C.; Janoušková, M.; Mrnka, L.; Rydlová, J.

    2017-01-01

    Roč. 113, OCT (2017), s. 143-0152 ISSN 0038-0717 Institutional support: RVO:61388971 Keywords : Community composition * Ecological guilds * Primary succession Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.857, year: 2016

  17. Developing mental health services in Nigeria : the impact of a community-based mental health awareness programme.

    Science.gov (United States)

    Eaton, Julian; Agomoh, Ahamefula O

    2008-07-01

    This grass-roots level mental health awareness programme considerably increased use of community-based mental health services in a part of Nigeria where knowledge about treatability of mental illness was limited. The benefits of the programme were sustained for a significant period after the initial awareness programme. In order for attitude changes to be reinforced, similar awareness programmes must be repeated at regular intervals.

  18. Microbial decomposition of dead grassland roots and its influence on the carbon cycle under changing precipitation patterns

    Science.gov (United States)

    Becerra, C.; Schimel, J.

    2013-12-01

    Soil is the largest reservoir of organic carbon in terrestrial ecosystems and as such, represents a potential sink for carbon dioxide.The decomposition products of dead roots buried in the soil is a contributor to soil organic carbon. However, changing precipitation patterns may affect its fate by influencing the microbial community responsible for decomposing dead roots. To assess the impact of changing precipitation patterns, we constructed microcosms with grassland soil collected from the UCSB Sedgwick Reserve, an active and long-term research site, and dead roots from greenhouse-grown grass, Bromus diandrus. Microcosms were wetted continuously, every seven days, or every twenty days. Sets of microcosms were periodically deconstructed to assess the soil versus the roots-associated microbial community and its function. Differences in respiration rates of microcosms continuously wetted or wetted every 7 days versus microcosms wetted every 20 days existed for the first 70 days. After which, no differences in respiration rates were seen with microcosms containing roots and the no roots control. Relatedly, after a 70% roots mass loss by day 50, there was no difference in the respiration rate of microcosms containing roots and the no roots control. More than half of the roots mass loss had occurred by 30 days. By the end of the incubation period, the roots mass loss in continuously wet and 7-day wetted microcosms were over 80% compared to 67% for the microcosms wetted every 20 days. Microbial biomass in the soil were constant over time and showed no difference in treatment except with the no roots control during the first half of the incubation period. Hydrolytic enzyme activities (β-1,4-glucosidase; α-1,4-glucosidase; β-1,4-xylosidase; β-1,4-cellobiosidase) on the roots versus the soil attached to the roots were over an order greater and decreased faster with the exception of N-acetyl-glucosaminidase and acid phosphatase. Oxidative enzyme activities (phenol

  19. Arbuscular common mycorrhizal networks mediate intra- and interspecific interactions of two prairie grasses.

    Science.gov (United States)

    Weremijewicz, Joanna; da Silveira Lobo O'Reilly Sternberg, Leonel; Janos, David P

    2018-01-01

    Arbuscular mycorrhizal fungi form extensive common mycorrhizal networks (CMNs) that may interconnect neighboring root systems of the same or different plant species, thereby potentially influencing the distribution of limiting mineral nutrients among plants. We examined how CMNs affected intra- and interspecific interactions within and between populations of Andropogon gerardii, a highly mycorrhiza dependent, dominant prairie grass and Elymus canadensis, a moderately dependent, subordinate prairie species. We grew A. gerardii and E. canadensis alone and intermixed in microcosms, with individual root systems isolated, but either interconnected by CMNs or with CMNs severed weekly. CMNs, which provided access to a large soil volume, improved survival of both A. gerardii and E. canadensis, but intensified intraspecific competition for A. gerardii. When mixed with E. canadensis, A. gerardii overyielded aboveground biomass in the presence of intact CMNs but not when CMNs were severed, suggesting that A. gerardii with intact CMNs most benefitted from weaker interspecific than intraspecific interactions across CMNs. CMNs improved manganese uptake by both species, with the largest plants receiving the most manganese. Enhanced growth in consequence of improved mineral nutrition led to large E. canadensis in intact CMNs experiencing water-stress, as indicated by 13 C isotope abundance. Our findings suggest that in prairie plant communities, CMNs may influence mineral nutrient distribution, water relations, within-species size hierarchies, and between-species interactions.

  20. Culture change, leadership and the grass-roots workforce.

    Science.gov (United States)

    Edwards, Mark; Penlington, Clare; Kalidasan, Varadarajan; Kelly, Tony

    2014-08-01

    The NHS is arguably entering its most challenging era. It is being asked to do more for less and, in parallel, a cultural shift in response to its described weaknesses has been prescribed. The definition of culture, the form this change should take and the mechanism to achieve it are not well understood. The complexity of modern healthcare requires that we evolve our approach to the workforce and enhance our understanding of the styles of leadership that are required in order to bring about this cultural change. Identification of leaders within the workforce and dissemination of a purposeful and strategic quality improvement agenda, in part defined by the general workforce, are important components in establishing the change that the organisation currently requires. We are implementing this approach locally by identifying and developing grassroots networks linked to a portfolio of safety and quality projects. © 2014 Royal College of Physicians.

  1. Grass-root Mobilisation and Citizen Participation: Issues and Challenges.

    Science.gov (United States)

    Vasoo, S.

    1991-01-01

    Mobilization of citizen participation in grassroots organizations can be adversely affected when grassroots leaders perceive a lack of support. Periodic organizational diagnosis can lead to more equitable division of responsibilities and recruitment of more leaders and skilled participants. (SK)

  2. Native arbuscular mycorrhizal symbiosis alters foliar bacterial community composition.

    Science.gov (United States)

    Poosakkannu, Anbu; Nissinen, Riitta; Kytöviita, Minna-Maarit

    2017-11-01

    The effects of arbuscular mycorrhizal (AM) fungi on plant-associated microbes are poorly known. We tested the hypothesis that colonization by an AM fungus affects microbial species richness and microbial community composition of host plant tissues. We grew the grass, Deschampsia flexuosa in a greenhouse with or without the native AM fungus, Claroideoglomus etunicatum. We divided clonally produced tillers into two parts: one inoculated with AM fungus spores and one without AM fungus inoculation (non-mycorrhizal, NM). We characterized bacterial (16S rRNA gene) and fungal communities (internal transcribed spacer region) in surface-sterilized leaf and root plant compartments. AM fungus inoculation did not affect microbial species richness or diversity indices in leaves or roots, but the AM fungus inoculation significantly affected bacterial community composition in leaves. A total of three OTUs in leaves belonging to the phylum Firmicutes positively responded to the presence of the AM fungus in roots. Another six OTUs belonging to the Proteobacteria (Alpha, Beta, and Gamma) and Bacteroidetes were significantly more abundant in NM plants when compared to AM fungus-inoculated plants. Further, there was a significant correlation between plant dry weight and leaf microbial community compositional shift. Also, there was a significant correlation between leaf bacterial community compositional shift and foliar nitrogen content changes due to AM fungus inoculation. The results suggest that AM fungus colonization in roots has a profound effect on plant physiology that is reflected in leaf bacterial community composition.

  3. UV-B-mediated changes on below-ground communities associated with the roots of Acer saccharum

    International Nuclear Information System (INIS)

    Klironomos, J.N.; Allen, M.F.

    1995-01-01

    1. Little is known about how exposure to UV-B radiation affects rhizosphere microbes. Rhizosphere organisms are fed primarily by root-derived substrates and fulfil functions such as mineralization, immobilization, decomposition, pathogeneity and improvement of plant nutrition; they form the base of the below-ground food web. 2. In this study, we exposed Sugar Maple (Acer saccharum) seedlings to UV-B radiation in order to determine if UV-B influences the activities of mycorrhizal and non-mycorrhizal fungi, bacteria and microbe-feeding arthropods in the rhizosphere. 3. Below-ground organisms are greatly affected by UV-B radiation. Overall, carbon-flow in the plant soil system was shifted from a mutualistic-closed, mycorrhizal-dominated system to an opportunist-open, saprobe/pathogen-dominated one. (author)

  4. Location, Root Proximity, and Glyphosate-use History Modulate the Effects of Glyphosate on Fungal Community Networks of Wheat

    Science.gov (United States)

    Glyphosate is the most-used herbicide worldwide and an essential tool for weed control in no-till cropping systems. However, concerns have been raised regarding the long-term effects of glyphosate on soil microbial communities. We examined the impact of repeated glyphosate application on bulk and rh...

  5. Root-associated fungal communities along a primary succession on a mine spoil: Distinct ecological guilds assemble differently

    Czech Academy of Sciences Publication Activity Database

    Kolaříková, Zuzana; Kohout, Petr; Krüger, Claudia; Janoušková, Martina; Mrnka, Libor; Rydlová, Jana

    2017-01-01

    Roč. 113, OCT 2017 (2017), s. 143-152 ISSN 0038-0717 R&D Projects: GA ČR GA13-10377S Institutional support: RVO:67985939 Keywords : community composition * ecological guilds * primary succession Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 4.857, year: 2016

  6. Early root overproduction not triggered by nutrients decisive for competitive success belowground.

    Directory of Open Access Journals (Sweden)

    Francisco M Padilla

    Full Text Available Theory predicts that plant species win competition for a shared resource by more quickly preempting the resource in hotspots and by depleting resource levels to lower concentrations than its competitors. Competition in natural grasslands largely occurs belowground, but information regarding root interactions is limited, as molecular methods quantifying species abundance belowground have only recently become available.In monoculture, the grass Festuca rubra had higher root densities and a faster rate of soil nitrate depletion than Plantago lanceolata, projecting the first as a better competitor for nutrients. However, Festuca lost in competition with Plantago. Plantago not only replaced the lower root mass of its competitor, but strongly overproduced roots: with only half of the plants in mixture than in monoculture, Plantago root densities in mixture were similar or higher than those in its monocultures. These responses occurred equally in a nutrient-rich and nutrient-poor soil layer, and commenced immediately at the start of the experiment when root densities were still low and soil nutrient concentrations high.Our results suggest that species may achieve competitive superiority for nutrients by root growth stimulation prior to nutrient depletion, induced by the presence of a competitor species, rather than by a better ability to compete for nutrients per se. The root overproduction by which interspecific neighbors are suppressed independent of nutrient acquisition is consistent with predictions from game theory. Our results emphasize that root competition may be driven by other mechanisms than is currently assumed. The long-term consequences of these mechanisms for community dynamics are discussed.

  7. [Community composition and diversity of endophytic fungi from roots of Sinopodophyllum hexandrum in forest of Upper-north mountain of Qinghai province].

    Science.gov (United States)

    Ning, Yi; Li, Yan-Ling; Zhou, Guo-Ying; Yang, Lu-Cun; Xu, Wen-Hua

    2016-04-01

    High throughput sequencing technology is also called Next Generation Sequencing (NGS), which can sequence hundreds and thousands sequences in different samples at the same time. In the present study, the culture-independent high throughput sequencing technology was applied to sequence the fungi metagenomic DNA of the fungal internal transcribed spacer 1(ITS 1) in the root of Sinopodophyllum hexandrum. Sequencing data suggested that after the quality control, 22 565 reads were remained. Cluster similarity analysis was done based on 97% sequence similarity, which obtained 517 OTUs for the three samples (LD1, LD2 and LD3). All the fungi which identified from all the reads of OTUs based on 0.8 classification thresholds using the software of RDP classifier were classified as 13 classes, 35 orders, 44 family, 55 genera. Among these genera, the genus of Tetracladium was the dominant genera in all samples(35.49%, 68.55% and 12.96%).The Shannon's diversity indices and the Simpson indices of the endophytic fungi in the samples ranged from 1.75-2.92, 0.11-0.32, respectively.This is the first time for applying high through put sequencing technol-ogyto analyze the community composition and diversity of endophytic fungi in the medicinal plant, and the results showed that there were hyper diver sity and high community composition complexity of endophytic fungi in the root of S. hexandrum. It is also proved that the high through put sequencing technology has great advantage for analyzing ecommunity composition and diversity of endophtye in the plant. Copyright© by the Chinese Pharmaceutical Association.

  8. Root fractures

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Christensen, Søren Steno Ahrensburg; Tsilingaridis, Georgios

    2012-01-01

    The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed....

  9. Effect of soil salinity and nutrient levels on the community structure of the root-associated bacteria of the facultative halophyte, Tamarix ramosissima, in southwestern United States.

    Science.gov (United States)

    Taniguchi, Takeshi; Imada, Shogo; Acharya, Kumud; Iwanaga, Fumiko; Yamanaka, Norikazu

    2015-01-01

    Tamarix ramosissima is a tree species that is highly resistant to salt and drought. The Tamarix species survives in a broad range of environmental salt levels, and invades major river systems in southwestern United States. It may affect root-associated bacteria (RB) by increasing soil salts and nutrients. The effects of RB on host plants may vary even under saline conditions, and the relationship may be important for T. ramosissima. However, to the best of our knowledge, there have been no reports relating to T. ramosissima RB and its association with salinity and nutrient levels. In this study, we have examined this association and the effect of arbuscular mycorrhizal colonization of T. ramosissima on RB because a previous study has reported that colonization of arbuscular mycorrhizal fungi affected the rhizobacterial community (Marschner et al., 2001). T. ramosissima roots were collected from five locations with varying soil salinity and nutrient levels. RB community structures were examined by terminal restriction fragment (T-RF) length polymorphism, cloning, and sequencing analyses. The results suggest that RB richness, or the diversity of T. ramosissima, have significant negative relationships with electrical conductivity (EC), sodium concentration (Na), and the colonization of arbuscular mycorrhizal fungi, but have a significant positive relationship with phosphorus in the soil. However, at each T-RF level, positive correlations between the emergence of some T-RFs and EC or Na were observed. These results indicate that high salinity decreased the total number of RB species, but some saline-tolerant RB species multiplied with increasing salinity levels. The ordination scores of nonmetric multidimensional scale analysis of RB community composition show significant relationships with water content, calcium concentration, available phosphorus, and total nitrogen. These results indicate that the RB diversity and community composition of T. ramosissima are affected

  10. Bioenergy production from roadside grass

    DEFF Research Database (Denmark)

    Meyer, Ane Katharina Paarup; Ehimen, Ehiazesebhor Augustine; Holm-Nielsen, Jens Bo

    2014-01-01

    This paper presents a study of the feasibility of utilising roadside vegetation for biogas production in Denmark. The potential biomass yield, methane yields, and the energy balances of using roadside grass for biogas production was investigated based on spatial analysis. The results show...

  11. Genetic differences in root mass of Lolium perenne varieties under field conditions

    NARCIS (Netherlands)

    Deru, J.G.C.; Schilder, H.; Schoot, van der J.R.; Eekeren, van N.J.M.

    2014-01-01

    Although grasses have dense rooting systems, nutrient uptake and productivity can be increased, and N-leaching reduced, if rooting is further improved. The variation in root mass of 16 varieties of Lolium perenne was studied under field conditions in two experiments on sandy soil in The Netherlands.

  12. Revisiting the two-layer hypothesis: coexistence of alternative functional rooting strategies in savannas.

    Science.gov (United States)

    Holdo, Ricardo M

    2013-01-01

    The two-layer hypothesis of tree-grass coexistence posits that trees and grasses differ in rooting depth, with grasses exploiting soil moisture in shallow layers while trees have exclusive access to deep water. The lack of clear differences in maximum rooting depth between these two functional groups, however, has caused this model to fall out of favor. The alternative model, the demographic bottleneck hypothesis, suggests that trees and grasses occupy overlapping rooting niches, and that stochastic events such as fires and droughts result in episodic tree mortality at various life stages, thus preventing trees from otherwise displacing grasses, at least in mesic savannas. Two potential problems with this view are: 1) we lack data on functional rooting profiles in trees and grasses, and these profiles are not necessarily reflected by differences in maximum or physical rooting depth, and 2) subtle, difficult-to-detect differences in rooting profiles between the two functional groups may be sufficient to result in coexistence in many situations. To tackle this question, I coupled a plant uptake model with a soil moisture dynamics model to explore the environmental conditions under which functional rooting profiles with equal rooting depth but different depth distributions (i.e., shapes) can coexist when competing for water. I show that, as long as rainfall inputs are stochastic, coexistence based on rooting differences is viable under a wide range of conditions, even when these differences are subtle. The results also indicate that coexistence mechanisms based on rooting niche differentiation are more viable under some climatic and edaphic conditions than others. This suggests that the two-layer model is both viable and stochastic in nature, and that a full understanding of tree-grass coexistence and dynamics may require incorporating fine-scale rooting differences between these functional groups and realistic stochastic climate drivers into future models.

  13. Colonization and community structure of arbuscular mycorrhizal fungi in maize roots at different depths in the soil profile respond differently to phosphorus inputs on a long-term experimental site.

    Science.gov (United States)

    Wang, Chao; White, Philip J; Li, Chunjian

    2017-05-01

    Effects of soil depth and plant growth stages on arbuscular mycorrhizal fungal (AMF) colonization and community structure in maize roots and their potential contribution to host plant phosphorus (P) nutrition under different P-fertilizer inputs were studied. Research was conducted on a long-term field experiment over 3 years. AMF colonization was assessed by AM colonization rate and arbuscule abundances and their potential contribution to host P nutrition by intensity of fungal alkaline phosphatase (ALP)/acid phosphatase (ACP) activities and expressions of ZmPht1;6 and ZmCCD8a in roots from the topsoil and subsoil layer at different growth stages. AMF community structure was determined by specific amplification of 18S rDNA. Increasing P inputs up to 75-100 kg ha -1  yr -1 increased shoot biomass and P content but decreased AMF colonization and interactions between AMF and roots. AM colonization rate, intensity of fungal ACP/ALP activities, and expression of ZmPht1;6 in roots from the subsoil were greater than those from topsoil at elongation and silking but not at the dough stage when plants received adequate or excessive P inputs. Neither P input nor soil depth influenced the number of AMF operational taxonomic units (OTUs) present in roots, but P-fertilizer input, in particular, influenced community composition and relative AMF abundance. In conclusion, although increasing P inputs reduce AMF colonization and influence AMF community structure, AMF can potentially contribute to plant P nutrition even in well-fertilized soils, depending on the soil layer in which roots are located and the growth stage of host plants.

  14. Resource Availability Alters Biodiversity Effects in Experimental Grass-Forb Mixtures.

    Directory of Open Access Journals (Sweden)

    Alrun Siebenkäs

    Full Text Available Numerous experiments, mostly performed in particular environments, have shown positive diversity-productivity relationships. Although the complementary use of resources is discussed as an important mechanism explaining diversity effects, less is known about how resource availability controls the strength of diversity effects and how this response depends on the functional composition of plant communities. We studied aboveground biomass production in experimental monocultures, two- and four-species mixtures assembled from two independent pools of four perennial grassland species, each representing two functional groups (grasses, forbs and two growth statures (small, tall, and exposed to different combinations of light and nutrient availability. On average, shade led to a decrease in aboveground biomass production of 24% while fertilization increased biomass production by 36%. Mixtures were on average more productive than expected from their monocultures (relative yield total, RYT>1 and showed positive net diversity effects (NE: +34% biomass increase; mixture minus mean monoculture biomass. Both trait-independent complementarity effects (TICE: +21% and dominance effects (DE: +12% positively contributed to net diversity effects, while trait-dependent complementarity effects were minor (TDCE: +1%. Shading did not alter diversity effects and overyielding. Fertilization decreased RYT and the proportion of biomass gain through TICE and TDCE, while DE increased. Diversity effects did not increase with species richness and were independent of functional group or growth stature composition. Trait-based analyses showed that the dominance of species with root and leaf traits related to resource conservation increased TICE. Traits indicating the tolerance of shade showed positive relationships with TDCE. Large DE were associated with the dominance of species with tall growth and low diversity in leaf nitrogen concentrations. Our field experiment shows that

  15. Impact of clay mineral, wood sawdust or root organic matter on the bacterial and fungal community structures in two aged PAH-contaminated soils.

    Science.gov (United States)

    Cébron, Aurélie; Beguiristain, Thierry; Bongoua-Devisme, Jeanne; Denonfoux, Jérémie; Faure, Pierre; Lorgeoux, Catherine; Ouvrard, Stéphanie; Parisot, Nicolas; Peyret, Pierre; Leyval, Corinne

    2015-09-01

    The high organic pollutant concentration of aged polycyclic aromatic hydrocarbon (PAH)-contaminated wasteland soils is highly recalcitrant to biodegradation due to its very low bioavailability. In such soils, the microbial community is well adapted to the pollution, but the microbial activity is limited by nutrient availability. Management strategies could be applied to modify the soil microbial functioning as well as the PAH contamination through various amendment types. The impact of amendment with clay minerals (montmorillonite), wood sawdust and organic matter plant roots on microbial community structure was investigated on two aged PAH-contaminated soils both in laboratory and 1-year on-site pot experiments. Total PAH content (sum of 16 PAHs of the US-EPA list) and polar polycyclic aromatic compounds (pPAC) were monitored as well as the available PAH fraction using the Tenax method. The bacterial and fungal community structures were monitored using fingerprinting thermal gradient gel electrophoresis (TTGE) method. The abundance of bacteria (16S rRNA genes), fungi (18S rRNA genes) and PAH degraders (PAH-ring hydroxylating dioxygenase and catechol dioxygenase genes) was followed through qPCR assays. Although the treatments did not modify the total and available PAH content, the microbial community density, structure and the PAH degradation potential changed when fresh organic matter was provided as sawdust and under rhizosphere influence, while the clay mineral only increased the percentage of catechol-1,2-dioxygenase genes. The abundance of bacteria and fungi and the percentage of fungi relative to bacteria were enhanced in soil samples supplemented with wood sawdust and in the plant rhizospheric soils. Two distinct fungal populations developed in the two soils supplemented with sawdust, i.e. fungi related to Chaetomium and Neurospora genera and Brachyconidiellopsis and Pseudallescheria genera, in H and NM soils respectively. Wood sawdust amendment favoured the

  16. Impact of Soil Salinity on the Structure of the Bacterial Endophytic Community Identified from the Roots of Caliph Medic (Medicago truncatula).

    Science.gov (United States)

    Yaish, Mahmoud W; Al-Lawati, Abbas; Jana, Gerry Aplang; Vishwas Patankar, Himanshu; Glick, Bernard R

    2016-01-01

    In addition to being a forage crop, Caliph medic (Medicago truncatula) is also a model legume plant and is used for research focusing on the molecular characterization of the interaction between rhizobia and plants. However, the endophytic microbiome in this plant is poorly defined. Endophytic bacteria play a role in supplying plants with the basic requirements necessary for growth and development. Moreover, these bacteria also play a role in the mechanism of salinity stress adaptation in plants. As a prelude to the isolation and utilization of these bacteria in Caliph medic farming, 41 bacterial OTUs were identified in this project from within the interior of the roots of this plant by pyrosequencing of the small ribosomal subunit gene (16S rDNA) using a cultivation-independent approach. In addition, the differential abundance of these bacteria was studied following exposure of the plants to salinity stress. About 29,064 high-quality reads were obtained from the sequencing of six libraries prepared from control and salinity-treated tissues. Statistical analysis revealed that the abundance of ~70% of the OTUs was significantly (p ≤ 0.05) altered in roots that were exposed to salinity stress. Sequence analysis showed a similarity between some of the identified species and other, known, growth-promoting bacteria, marine and salt-stressed soil-borne bacteria, and nitrogen-fixing bacterial isolates. Determination of the amendments to the bacterial community due to salinity stress in Caliph medic provides a crucial step toward developing an understanding of the association of these endophytes, under salt stress conditions, in this model plant. To provide direct evidence regarding their growth promoting activity, a group of endophytic bacteria were isolated from inside of plant roots using a cultivation-dependent approach. Several of these isolates were able to produce ACC-deaminase, ammonia and IAA; and to solubilize Zn+2 and PO4-3. This data is consistent with the

  17. Impact of Soil Salinity on the Structure of the Bacterial Endophytic Community Identified from the Roots of Caliph Medic (Medicago truncatula.

    Directory of Open Access Journals (Sweden)

    Mahmoud W Yaish

    Full Text Available In addition to being a forage crop, Caliph medic (Medicago truncatula is also a model legume plant and is used for research focusing on the molecular characterization of the interaction between rhizobia and plants. However, the endophytic microbiome in this plant is poorly defined. Endophytic bacteria play a role in supplying plants with the basic requirements necessary for growth and development. Moreover, these bacteria also play a role in the mechanism of salinity stress adaptation in plants. As a prelude to the isolation and utilization of these bacteria in Caliph medic farming, 41 bacterial OTUs were identified in this project from within the interior of the roots of this plant by pyrosequencing of the small ribosomal subunit gene (16S rDNA using a cultivation-independent approach. In addition, the differential abundance of these bacteria was studied following exposure of the plants to salinity stress. About 29,064 high-quality reads were obtained from the sequencing of six libraries prepared from control and salinity-treated tissues. Statistical analysis revealed that the abundance of ~70% of the OTUs was significantly (p ≤ 0.05 altered in roots that were exposed to salinity stress. Sequence analysis showed a similarity between some of the identified species and other, known, growth-promoting bacteria, marine and salt-stressed soil-borne bacteria, and nitrogen-fixing bacterial isolates. Determination of the amendments to the bacterial community due to salinity stress in Caliph medic provides a crucial step toward developing an understanding of the association of these endophytes, under salt stress conditions, in this model plant. To provide direct evidence regarding their growth promoting activity, a group of endophytic bacteria were isolated from inside of plant roots using a cultivation-dependent approach. Several of these isolates were able to produce ACC-deaminase, ammonia and IAA; and to solubilize Zn+2 and PO4-3. This data is

  18. Effect of a Bacterial Grass Culture on the Plant Growth and Disease Control in Tomato

    Directory of Open Access Journals (Sweden)

    Yong Seong Lee

    2017-12-01

    Full Text Available This study aimed to investigate the plant growth-promoting and biocontrol potential of a grass culture with Paenibacillus ehimensis KWN8 on tomato. For this experiment, treatments of a chemical fertilizer (F, a bacterial grass culture (G, a 1/3 volume of G plus 2/3 F (GF, and F plus a synthetic fungicide (FSf were applied to tomato leaves and roots. The result showed that the severity of Alternariasolani and Botrytiscinerea symptoms were significantly reduced after the application of the bacterial grass culture (G and GF and FSf. In addition, root mortality in G and GF was lower compared to F. Tomato plants treated with G or GF had better vegetative growth and yield compared to F. Application of G affected the fungal and bacterial populations in the soil. In conclusion, treatment with a bacterial grass culture decreased disease severity and increased tomato growth parameters. However, there were no statistically significant correlations between disease occurrence and tomato yields. This experiment presents the possibility to manage diseases of tomato in an environmentally friendly manner and to also increase the yield of tomato by using a grass culture broth containing P. ehimensis KWN38.

  19. N resource of grasses and N2-fixation of alfalfa in mono-culture and mixture

    International Nuclear Information System (INIS)

    Zhu Shuxiu

    1992-01-01

    The N behavior in alfalfa and gramineous forage grasses, tall fescue, siberian wild rye, wheat grass and awnless brome were studied in potting and pasture experiments in 1986-1988 by using 15 N isotope dilution technique. Comparison was made between the mixed culture and mono-culture. The % Ndff and %Ndfs of grasses were decreased by 14.19% and 20.76% respectively, while %Ndfa of alfalfa was increased by 20.22% in mixed culture as compared with mono-culture. The 15 N and soil N uptake data revealed that this enhancement was largely due to a lower competitive ability for soil N by alfalfa than by grass in mixed stands, causing the alfalfa to depend more on atmospheric N 2 fixation. 20.62%of N of grasses in mixed culture was from the N 2 -fixation by alfalfa, causing N level in root-sphere of alfalfa decreasing, which was considered to be one of the reasons that %Ndfa increased in mixed culture. N transfer may be carried out by the decomposition of roots and nodules of alfalfa plants

  20. Roots & Hollers

    OpenAIRE

    Kollman, Patrick L; Gorman, Thomas A

    2011-01-01

    Roots & Hollers, 2011 A documentary by Thomas Gorman & Patrick Kollman Master’s Project Abstract: Roots & Hollers uncovers the wild American ginseng trade, revealing a unique intersection between Asia and rural America. Legendary in Asia for its healing powers, ginseng helps sustain the livelihoods of thousands in Appalachia. A single root can sell for thousands of dollars at auction. Shot on-location in the mountains of Kentucky and West Virginia, this student doc...

  1. Transfer of radiocaesium to barley, rye grass and pea

    International Nuclear Information System (INIS)

    Oehlenschlaeger, M.; Gissel-Nielsen, G.

    1989-11-01

    In areas with intensive farming, as in Denmark, it is of great interest to identify possible countermeasures to be taken in order to reduce the longterm effects of radioactive contamination of arable land. The most important longer-lived radionuclides from the Chernobyl were 137 Cs and 134 Cs. The aim of the present project was to identify crops with relatively low or high root uptake of these two isotopes. Although such differences may be small, a shift in varieties might be a cost-effective way to reduce collective doses. The experiment was carried out at Risoe National Laboratory in the summer of 1988. The species used were: spring barley (Hordeum vulgare L) varieties: Golf, Apex, Anker, Sila; Perennial rye grass (Lolium perenne L.) varieties: Darbo (early) and Patoro (late); Italian rye-grass (Lolium multiflorum) variety: Prego; and pea (Pisum arvense L.) variety: Bodil. Each crop was grown in two types of soil, a clay-loam and an organic soil. 137 Cs was added to the clay-loam. The organic soil, which was contaminated with 137 Cs from the Chernobyl accident, was supplied with 134 Cs. Sila barley and Italian rye-grass were identified among the species tested as plants with a relative high uptake of radio-caesium. (author)

  2. The uptake of uranium from soil to vetiver grass (vetiver zizanioides (L.) nash)

    International Nuclear Information System (INIS)

    Luu Viet Hung; Bui Duy Cam; Dang Duc Nhan

    2012-01-01

    Uranium uptake of vetiver grass (Vetiveria zizanioides (L.) Nash) from Eutric Fluvisols (AK), Albic Acrisols (LP), Dystric Fluvisols (TT) and Ferralic Acrisols (TC) in northern Vietnam is assessed. The soils were mixed with aqueous solution of uranyl nitrate to make soils be contaminated with uranium at 0, 50, 100, 250 mg per kg before planting the grass. The efficiency of uranium uptake by the grass was assessed based on the soil-to-plant transfer factor (TF U , kg kg -1 ). It was found that the TF U values are dependent upon the soil properties. CEC facilitates the uptake and the increase soil pH could reduce the uptake and translocation of uranium in the plant. Organic matter content as well as ferrous and potassium inhibit the uranium uptake of the grass. It was revealed that the lower fertile soil the higher uranium uptake. The grass could tolerate to the high extent (up to 77%) of uranium in soils and could survive and grow well without fertilization. The translocation of uranium in root for all the soil types studies almost higher than that in its shoot. It seem that vetiver grass potentially be use for the purpose of phytoremediation of soils contaminated with uranium. (author)

  3. Plant Communities Rather than Soil Properties Structure Arbuscular Mycorrhizal Fungal Communities along Primary Succession on a Mine Spoil

    Science.gov (United States)

    Krüger, Claudia; Kohout, Petr; Janoušková, Martina; Püschel, David; Frouz, Jan; Rydlová, Jana

    2017-01-01

    Arbuscular mycorrhizal fungal (AMF) community assembly during primary succession has so far received little attention. It remains therefore unclear, which of the factors, driving AMF community composition, are important during ecosystem development. We addressed this question on a large spoil heap, which provides a mosaic of sites in different successional stages under different managements. We selected 24 sites of c. 12, 20, 30, or 50 years in age, including sites with spontaneously developing vegetation and sites reclaimed by alder plantations. On each site, we sampled twice a year roots of the perennial rhizomatous grass Calamagrostis epigejos (Poaceae) to determine AMF root colonization and diversity (using 454-sequencing), determined the soil chemical properties and composition of plant communities. AMF taxa richness was unaffected by site age, but AMF composition variation increased along the chronosequences. AMF communities were unaffected by soil chemistry, but related to the composition of neighboring plant communities of the sampled C. epigejos plants. In contrast, the plant communities of the sites were more distinctively structured than the AMF communities along the four successional stages. We conclude that AMF and plant community successions respond to different factors. AMF communities seem to be influenced by biotic rather than by abiotic factors and to diverge with successional age. PMID:28473828

  4. Grass or fern competition reduce growth and survival of planted tree seedlings

    Science.gov (United States)

    Larry H. McCormick; Todd W. Bowersox

    1997-01-01

    Bareroot seedlings of northern red oak, white ash, yellow-poplar and white pine were planted into herbaceous communities at three forested sites in central Pennsylvania that were clearcut 0 to 1 year earlier. Seedlings were grown 4 years in the presence and absence of either an established grass or hay-scented fern community. Survival and height growth were measured...

  5. Dynamic modeling of the cesium, strontium, and ruthenium transfer to grass and vegetables

    International Nuclear Information System (INIS)

    Renaud, P.; Real, J.; Maubert, H.; Roussel-Debet, S.

    1999-01-01

    From 1988 to 1993, the Nuclear Safety and Protection Institute (Institut de Protection et de Surete Nucleaire -- IPSN) conducted experimental programs focused on transfers to vegetation following accidental localized deposits of radioactive aerosols. In relation to vegetable crops (fruit, leaves, and root vegetables) and meadow grass these experiments have enabled a determination of the factors involved in the transfer of cesium, strontium, and ruthenium at successive harvests, or cuttings, in respect of various time lags after contamination. The dynamic modeling given by these results allows an evaluation of changes in the mass activity of vegetables and grass during the months following deposit. It constitutes part of the ASTRAL post-accident radioecology model

  6. Root patterning

    NARCIS (Netherlands)

    Scheres, Ben; Laskowski, Marta

    2016-01-01

    The mechanisms that pattern lateral root primordial are essential for the elaboration of root system architecture, a trait of key importance for future crop breeding. But which are most important: periodic or local cues? In this issue of Journal of Experimental Botany (pages 1411-1420), Kircher

  7. Genome-Wide Analysis of Syntenic Gene Deletion in the Grasses

    Science.gov (United States)

    Schnable, James C.; Freeling, Michael; Lyons, Eric

    2012-01-01

    The grasses, Poaceae, are one of the largest and most successful angiosperm families. Like many radiations of flowering plants, the divergence of the major grass lineages was preceded by a whole-genome duplication (WGD), although these events are not rare for flowering plants. By combining identification of syntenic gene blocks with measures of gene pair divergence and different frequencies of ancient gene loss, we have separated the two subgenomes present in modern grasses. Reciprocal loss of duplicated genes or genomic regions has been hypothesized to reproductively isolate populations and, thus, speciation. However, in contrast to previous studies in yeast and teleost fishes, we found very little evidence of reciprocal loss of homeologous genes between the grasses, suggesting that post-WGD gene loss may not be the cause of the grass radiation. The sets of homeologous and orthologous genes and predicted locations of deleted genes identified in this study, as well as links to the CoGe comparative genomics web platform for analyzing pan-grass syntenic regions, are provided along with this paper as a resource for the grass genetics community. PMID:22275519

  8. Analyzing rasters, vectors and time series using new Python interfaces in GRASS GIS 7

    Science.gov (United States)

    Petras, Vaclav; Petrasova, Anna; Chemin, Yann; Zambelli, Pietro; Landa, Martin; Gebbert, Sören; Neteler, Markus; Löwe, Peter

    2015-04-01

    GRASS GIS 7 is a free and open source GIS software developed and used by many scientists (Neteler et al., 2012). While some users of GRASS GIS prefer its graphical user interface, significant part of the scientific community takes advantage of various scripting and programing interfaces offered by GRASS GIS to develop new models and algorithms. Here we will present different interfaces added to GRASS GIS 7 and available in Python, a popular programming language and environment in geosciences. These Python interfaces are designed to satisfy the needs of scientists and programmers under various circumstances. PyGRASS (Zambelli et al., 2013) is a new object-oriented interface to GRASS GIS modules and libraries. The GRASS GIS libraries are implemented in C to ensure maximum performance and the PyGRASS interface provides an intuitive, pythonic access to their functionality. GRASS GIS Python scripting library is another way of accessing GRASS GIS modules. It combines the simplicity of Bash and the efficiency of the Python syntax. When full access to all low-level and advanced functions and structures from GRASS GIS library is required, Python programmers can use an interface based on the Python ctypes package. Ctypes interface provides complete, direct access to all functionality as it would be available to C programmers. GRASS GIS provides specialized Python library for managing and analyzing spatio-temporal data (Gebbert and Pebesma, 2014). The temporal library introduces space time datasets representing time series of raster, 3D raster or vector maps and allows users to combine various spatio-temporal operations including queries, aggregation, sampling or the analysis of spatio-temporal topology. We will also discuss the advantages of implementing scientific algorithm as a GRASS GIS module and we will show how to write such module in Python. To facilitate the development of the module, GRASS GIS provides a Python library for testing (Petras and Gebbert, 2014) which

  9. Plant Communities Suitable for Green Roofs in Arid Regions

    Directory of Open Access Journals (Sweden)

    Rachel Gioannini

    2018-05-01

    Full Text Available In extensive green roof settings, plant communities can be more robust than monocultures. In addition, native plants might be hardier and more ecologically sound choices than non-native plants in green roof systems. The objectives of this research were to (1 compare the performance of plant communities with that of monocultures and (2 compare the growth of natives to non-natives in a simulated green roof setting. We conducted a two-year experiment at an outdoor site in a desert environment using four plant morphological types (groundcover, forb, succulent and grass. Native plants selected were Chrysactinia mexicana, Melampodium leucanthum, Euphorbia antisyphilitica, and Nassella tenuissima, and non-natives were Delosperma nubigenum, Stachys byzantina, Sedum kamtschiaticum and Festuca glauca. Plants were assigned randomly to either monoculture or community and grown in 1 m × 1 m custom-built trays filled with 15 cm of a proprietary blend of 50/20/30 lightweight aggregate/sand/compost (by volume. Native forb, Melampodium, in community had greater coverage for four of the five measurements in the first year over native forb in monoculture and non-native forb regardless of setting. Native forb coverage was also greater than non-native forb for three of the four measurements in year 2, regardless of setting. Coverage of native grass was significantly greater than non-native grasses throughout the experiment. Coverage was also greater for eight of nine measurements for native succulent over non-natives succulent. However, non-native groundcover coverage was significantly greater than native groundcover for seven of nine measurements. On 1 November 2016, relative water content (RWC for succulents (p = 0.0424 was greatest for native Euphorbia in monoculture at 88%. Native Euphorbia also had greater RWC than non-native Sedum on 4 April 2017 (78% and 4 July 2017 (80%. However, non-native Sedum had greater root length (6548 cm, root dry weight (12.1 g

  10. Checklist of Serengeti Ecosystem Grasses

    Science.gov (United States)

    Ficinski, Paweł; Vorontsova, Maria

    2016-01-01

    Abstract We present the first taxonomic checklist of the Poaceae species of the Serengeti, Tanzania. A review of the literature and herbarium specimens recorded 200 species of grasses, in line with similar studies in other parts of East Africa. The checklist is supported by a total of 939 herbarium collections. Full georeferenced collection data is made available alongside a summary checklist in pdf format. More than a quarter of the species are known from a single collection highlighting the need for further research, especially concerning the rare species and their distribution. PMID:27226761

  11. Checklist of Serengeti Ecosystem Grasses.

    Science.gov (United States)

    Williams, Emma Victoria; Elia Ntandu, John; Ficinski, Paweł; Vorontsova, Maria

    2016-01-01

    We present the first taxonomic checklist of the Poaceae species of the Serengeti, Tanzania. A review of the literature and herbarium specimens recorded 200 species of grasses, in line with similar studies in other parts of East Africa. The checklist is supported by a total of 939 herbarium collections. Full georeferenced collection data is made available alongside a summary checklist in pdf format. More than a quarter of the species are known from a single collection highlighting the need for further research, especially concerning the rare species and their distribution.

  12. 238U, and its decay products, in grasses from an abandoned uranium mine

    Science.gov (United States)

    Childs, Edgar; Maskall, John; Millward, Geoffrey

    2016-04-01

    Bioaccumulation of radioactive contaminants by plants is of concern particularly where the sward is an essential part of the diet of ruminants. The abandoned South Terras uranium mine, south west England, had primary deposits of uraninite (UO2) and pitchblende (U3O8), which contained up to 30% uranium. When the mine was active uranium and radium were extracted but following closure it was abandoned without remediation. Waste rock and gangue, consisting of inefficiently processed minerals, were spread around the site, including a field where ruminants are grazed. Here we report the activity concentrations of 238U, 235U 214,210Pb, and the concentrations of selected metals in the soils, roots and leaves of grasses taken from the contaminated field. Soil samples were collected at the surface, and at 30 cm depth, using an auger along a 10-point transect in the field from the foot of a waste heap. Whole, individual grass plants were removed with a spade, ensuring that their roots were intact. The soils and roots and grass leaves were freeze-dried. Activity concentrations of the radionuclides were determined by gamma spectroscopy, following 30 days incubation for development of secular equilibrium. Dried soils, roots and grasses were also digested in aqua regia and the concentrations of elements determined by ICP techniques. Maximum activity concentrations of 238U, 235U, 214Pb and 210Pb surface soils were 63,300, 4,510, 23,300 and 49,400 Bq kg-1, respectively. The mean 238U:235U ratio was 11.8 ± 1.8, an order of magnitude lower than the natural value of 138, indicating disequilibrium within the decay chain due to mineral processing. Radionuclides in the roots had 5 times lower concentration and only grass leaves in the vicinity of the waste heap had measureable values. The mean soil to root transfer factor for 238U was 36%, the mean root to leaf was 3% and overall only 0.7% of 238U was transferred from the soil to the leaves. The roots contained 0.8% iron, possibly as

  13. Mitochondrial Disease Sequence Data Resource (MSeqDR): A global grass-roots consortium to facilitate deposition, curation, annotation, and integrated analysis of genomic data for the mitochondrial disease clinical and research communities

    NARCIS (Netherlands)

    M.J. Falk (Marni J.); L. Shen (Lishuang); M. Gonzalez (Michael); J. Leipzig (Jeremy); M.T. Lott (Marie T.); A.P.M. Stassen (Alphons P.M.); M.A. Diroma (Maria Angela); D. Navarro-Gomez (Daniel); P. Yeske (Philip); R. Bai (Renkui); R.G. Boles (Richard G.); V. Brilhante (Virginia); D. Ralph (David); J.T. DaRe (Jeana T.); R. Shelton (Robert); S.F. Terry (Sharon); Z. Zhang (Zhe); W.C. Copeland (William C.); M. van Oven (Mannis); H. Prokisch (Holger); D.C. Wallace; M. Attimonelli (Marcella); D. Krotoski (Danuta); S. Zuchner (Stephan); X. Gai (Xiaowu); S. Bale (Sherri); J. Bedoyan (Jirair); D.M. Behar (Doron); P. Bonnen (Penelope); L. Brooks (Lisa); C. Calabrese (Claudia); S. Calvo (Sarah); P.F. Chinnery (Patrick); J. Christodoulou (John); D. Church (Deanna); R. Clima (Rosanna); B.H. Cohen (Bruce H.); R.G.H. Cotton (Richard); I.F.M. de Coo (René); O. Derbenevoa (Olga); J.T. den Dunnen (Johan); D. Dimmock (David); G. Enns (Gregory); G. Gasparre (Giuseppe); A. Goldstein (Amy); I. Gonzalez (Iris); K. Gwinn (Katrina); S. Hahn (Sihoun); R.H. Haas (Richard H.); H. Hakonarson (Hakon); M. Hirano (Michio); D. Kerr (Douglas); D. Li (Dong); M. Lvova (Maria); F. Macrae (Finley); D. Maglott (Donna); E. McCormick (Elizabeth); G. Mitchell (Grant); V.K. Mootha (Vamsi K.); Y. Okazaki (Yasushi); A. Pujol (Aurora); M. Parisi (Melissa); J.C. Perin (Juan Carlos); E.A. Pierce (Eric A.); V. Procaccio (Vincent); S. Rahman (Shamima); H. Reddi (Honey); H. Rehm (Heidi); E. Riggs (Erin); R.J.T. Rodenburg (Richard); Y. Rubinstein (Yaffa); R. Saneto (Russell); M. Santorsola (Mariangela); C. Scharfe (Curt); C. Sheldon (Claire); E.A. Shoubridge (Eric); D. Simone (Domenico); B. Smeets (Bert); J.A.M. Smeitink (Jan); C. Stanley (Christine); A. Suomalainen (Anu); M.A. Tarnopolsky (Mark); I. Thiffault (Isabelle); D.R. Thorburn (David R.); J.V. Hove (Johan Van); L. Wolfe (Lynne); L.-J. Wong (Lee-Jun)

    2015-01-01

    textabstractSuccess rates for genomic analyses of highly heterogeneous disorders can be greatly improved if a large cohort of patient data is assembled to enhance collective capabilities for accurate sequence variant annotation, analysis, and interpretation. Indeed, molecular diagnostics requires

  14. Root resorption

    DEFF Research Database (Denmark)

    Kjaer, Inger

    2014-01-01

    Introduction: This paper summarizes the different conditions, which have a well-known influence on the resorption of tooth roots, exemplified by trauma and orthodontic treatment. The concept of the paper is to summarize and explain symptoms and signs of importance for avoiding resorption during...... orthodontic treatment. The Hypothesis: The hypothesis in this paper is that three different tissue layers covering the root in the so-called periroot sheet can explain signs and symptoms of importance for avoiding root resorption during orthodontic treatment. These different tissue layers are; outermost...... processes provoked by trauma and orthodontic pressure. Inflammatory reactions are followed by resorptive processes in the periroot sheet and along the root surface. Evaluation of the Hypothesis: Different morphologies in the dentition are signs of abnormal epithelium or an abnormal mesodermal layer. It has...

  15. Changes in Metabolically Active Bacterial Community during Rumen Development, and Their Alteration by Rhubarb Root Powder Revealed by 16S rRNA Amplicon Sequencing.

    Science.gov (United States)

    Wang, Zuo; Elekwachi, Chijioke; Jiao, Jinzhen; Wang, Min; Tang, Shaoxun; Zhou, Chuanshe; Tan, Zhiliang; Forster, Robert J

    2017-01-01

    The objective of this present study was to explore the initial establishment of metabolically active bacteria and subsequent evolution in four fractions: rumen solid-phase (RS), liquid-phase (RL), protozoa-associated (RP), and epithelium-associated (RE) through early weaning and supplementing rhubarb root powder in 7 different age groups (1, 10, 20, 38, 41, 50, and 60 d) during rumen development. Results of the 16S rRNA sequencing based on RNA isolated from the four fractions revealed that the potentially active bacterial microbiota in four fractions were dominated by the phyla Proteobacteria, Firmicutes , and Bacteroidetes regardless of different ages. An age-dependent increment of Chao 1 richness was observed in the fractions of RL and RE. The principal coordinate analysis (PCoA) indicated that samples in four fractions all clustered based on different age groups, and the structure of the bacterial community in RE was distinct from those in other three fractions. The abundances of Proteobacteria decreased significantly ( P < 0.05) with age, while increases in the abundances of Firmicutes and Bacteroidetes were noted. At the genus level, the abundance of the predominant genus Mannheimia in the Proteobacteria phylum decreased significantly ( P < 0.05) after 1 d, while the genera Quinella, Prevotella, Fretibacterium, Ruminococcus, Lachnospiraceae NK3A20 group , and Atopobium underwent different manners of increases and dominated the bacterial microbiota across four fractions. Variations of the distributions of some specific bacterial genera across fractions were observed, and supplementation of rhubarb affected the relative abundance of various genera of bacteria.

  16. The relative importance of different grass components in controlling runoff and erosion on a hillslope under simulated rainfall

    Science.gov (United States)

    Li, Changjia; Pan, Chengzhong

    2018-03-01

    The effects of vegetation cover on overland flow and erosion processes on hillslopes vary with vegetation type and spatial distribution and the different vegetation components, including the above- and below-ground biomass. However, few attempts have been made to quantify how these factors affect erosion processes. Field experimental plots (5 m × 2 m) with a slope of approximately 25° were constructed and simulated rainfall (60 mm hr-1) (Rainfall) and simulated rainfall combined with upslope overland flow (20 L min-1) (Rainfall + Flow) were applied. Three grass species were planted, specifically Astragalus adsurgens (A. adsurgens), Medicago sativa (M. sativa) and Cosmos bipinnatus (C. bipinnatus). To isolate and quantify the relative contributions of the above-ground grass parts (stems, litter cover and leaves) and the roots to reducing surface runoff and erosion, each of the three grass species was subjected to three treatments: intact grass control (IG), no litter or leaves (only the grass stems and roots were reserved) (NLL), and only roots remaining (OR). The results showed that planting grass significantly reduced overland flow rate and velocity and sediment yield, and the mean reductions were 21.8%, 29.1% and 67.1%, respectively. M. sativa performed the best in controlling water and soil losses due to its thick canopy and dense, fine roots. Grasses reduced soil erosion mainly during the early stage of overland flow generation. The above-ground grass parts primarily contributed to reducing overland flow rate and velocity, with mean relative contributions of 64% and 86%, respectively. The roots played a predominant role in reducing soil erosion, with mean contribution of 84%. Due to the impact of upslope inflow, overland flow rate and velocity and sediment yield increased under the Rainfall + Flow conditions. The results suggest that grass species on downslope parts of semi-arid hillslopes performed better in reducing water and soil losses. This study is

  17. Enhancing GRASS data communication with videographic technology

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, R.G. [Argonne National Lab., IL (United States); Gerdes, D.; Youngs, D. [Army Construction Engineering Research Lab., Champaign, IL (United States)

    1992-07-01

    Research at Argonne National Laboratory and the US Army Construction Engineering Research Laboratory has shown that computer videographic technology can be used to assist visualization and communication of GIS-generated geographic information. Videographic tools can be used to make results of GRASS analyses clear to decision-makers and to public interest groups, as well as to help GRASS users visualize geographic data more easily. Useful videographic visualization tools include graphic overlay of GRASS layers onto panchromatic images, allowing landscape features to be associated with GIS classifications; draping of GIS layers onto terrain models to create shaded relief maps; and incorporation of photographic imagery into GIS graphics. Useful videographic communications capabilities include convenient, direct interface to video formats, allowing incorporation of live video into GRASS graphics and output of GRASS graphics to video; convenient output of high-quality slides and prints; and enhanced labeling and editing of GRASS images. Conversion of GRASS imagery to standard videographic file formats also facilitates incorporation of GRASS images into other software programs, such as database and work-processing packages.

  18. Enhancing GRASS data communication with videographic technology

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, R.G. (Argonne National Lab., IL (United States)); Gerdes, D.; Youngs, D. (Army Construction Engineering Research Lab., Champaign, IL (United States))

    1992-01-01

    Research at Argonne National Laboratory and the US Army Construction Engineering Research Laboratory has shown that computer videographic technology can be used to assist visualization and communication of GIS-generated geographic information. Videographic tools can be used to make results of GRASS analyses clear to decision-makers and to public interest groups, as well as to help GRASS users visualize geographic data more easily. Useful videographic visualization tools include graphic overlay of GRASS layers onto panchromatic images, allowing landscape features to be associated with GIS classifications; draping of GIS layers onto terrain models to create shaded relief maps; and incorporation of photographic imagery into GIS graphics. Useful videographic communications capabilities include convenient, direct interface to video formats, allowing incorporation of live video into GRASS graphics and output of GRASS graphics to video; convenient output of high-quality slides and prints; and enhanced labeling and editing of GRASS images. Conversion of GRASS imagery to standard videographic file formats also facilitates incorporation of GRASS images into other software programs, such as database and work-processing packages.

  19. Thermogravimetric analysis of forest understory grasses

    Science.gov (United States)

    Thomas Elder; John S. Kush; Sharon M. Hermann

    2011-01-01

    Forest understory grasses are of significance in the initiation, establishment and maintenance of fire, whether used as a management tool or when occurring as wildfire. The fundamental thermal properties of such grasses are critical to their behavior in fire situations and have been investigated in the current work by the application of thermogravimetric analysis (TGA...

  20. SQ grass sublingual allergy immunotherapy tablet for disease-modifying treatment of grass pollen allergic rhinoconjunctivitis

    DEFF Research Database (Denmark)

    Dahl, Ronald; Roberts, Graham; de Blic, Jacques

    2016-01-01

    BACKGROUND: Allergy immunotherapy is a treatment option for allergic rhinoconjunctivitis (ARC). It is unique compared with pharmacotherapy in that it modifies the immunologic pathways that elicit an allergic response. The SQ Timothy grass sublingual immunotherapy (SLIT) tablet is approved in North...... America and throughout Europe for the treatment of adults and children (≥5 years old) with grass pollen-induced ARC. OBJECTIVE: The clinical evidence for the use of SQ grass SLIT-tablet as a disease-modifying treatment for grass pollen ARC is discussed in this review. METHODS: The review included...... the suitability of SQ grass SLIT-tablet for patients with clinically relevant symptoms to multiple Pooideae grass species, single-season efficacy, safety, adherence, coseasonal initiation, and cost-effectiveness. The data from the long-term SQ grass SLIT-tablet clinical trial that evaluated a clinical effect 2...

  1. Effect of two phyto hormone producer rhizobacteria on the bermuda grass growth response and tolerance to phenanthrene

    International Nuclear Information System (INIS)

    Guerrero-Zuniga, A.; Rojas-Contreras, A.; Rodriguez-Dorantes, A.; Montes-Villafan, S.

    2009-01-01

    Plant growth-promoting rhizobacteria (PGPR) are free-living bacteria that have the ability to relieve environmental stress in plants, increasing the plant growth potential. Of importance to phytoremediation, PGPR stimulate plant root development and enhance root growth.This study evaluated the growth response and the tolerance to phenanthrene of Bermuda grass: Cynodon dactylon inoculated with two phytohormone producer rhizobacteria: strains II and III, isolated from a contaminated soil with petroleum hydrocarbons. (Author)

  2. Effect of two phyto hormone producer rhizobacteria on the bermuda grass growth response and tolerance to phenanthrene

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero-Zuniga, A.; Rojas-Contreras, A.; Rodriguez-Dorantes, A.; Montes-Villafan, S.

    2009-07-01

    Plant growth-promoting rhizobacteria (PGPR) are free-living bacteria that have the ability to relieve environmental stress in plants, increasing the plant growth potential. Of importance to phytoremediation, PGPR stimulate plant root development and enhance root growth.This study evaluated the growth response and the tolerance to phenanthrene of Bermuda grass: Cynodon dactylon inoculated with two phytohormone producer rhizobacteria: strains II and III, isolated from a contaminated soil with petroleum hydrocarbons. (Author)

  3. OpenSimRoot: widening the scope and application of root architectural models.

    Science.gov (United States)

    Postma, Johannes A; Kuppe, Christian; Owen, Markus R; Mellor, Nathan; Griffiths, Marcus; Bennett, Malcolm J; Lynch, Jonathan P; Watt, Michelle

    2017-08-01

    OpenSimRoot is an open-source, functional-structural plant model and mathematical description of root growth and function. We describe OpenSimRoot and its functionality to broaden the benefits of root modeling to the plant science community. OpenSimRoot is an extended version of SimRoot, established to simulate root system architecture, nutrient acquisition and plant growth. OpenSimRoot has a plugin, modular infrastructure, coupling single plant and crop stands to soil nutrient and water transport models. It estimates the value of root traits for water and nutrient acquisition in environments and plant species. The flexible OpenSimRoot design allows upscaling from root anatomy to plant community to estimate the following: resource costs of developmental and anatomical traits; trait synergisms; and (interspecies) root competition. OpenSimRoot can model three-dimensional images from magnetic resonance imaging (MRI) and X-ray computed tomography (CT) of roots in soil. New modules include: soil water-dependent water uptake and xylem flow; tiller formation; evapotranspiration; simultaneous simulation of mobile solutes; mesh refinement; and root growth plasticity. OpenSimRoot integrates plant phenotypic data with environmental metadata to support experimental designs and to gain a mechanistic understanding at system scales. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  4. Adaptation and detoxification mechanisms of Vetiver grass (Chrysopogon zizanioides) growing on gold mine tailings.

    Science.gov (United States)

    Melato, F A; Mokgalaka, N S; McCrindle, R I

    2016-01-01

    Vetiver grass (Chrysopogon zizanioides) was investigated for its potential use in the rehabilitation of gold mine tailings, its ability to extract and accumulate toxic metals from the tailings and its metal tolerant strategies. Vetiver grass was grown on gold mine tailings soil, in a hothouse, and monitored for sixteen weeks. The mine tailings were highly acidic and had high electrical conductivity. Vetiver grass was able to grow and adapt well on gold mine tailings. The results showed that Vetiver grass accumulated large amounts of metals in the roots and restricted their translocation to the shoots. This was confirmed by the bioconcentration factor of Zn, Cu, and Ni of >1 and the translocation factor of <1 for all the metals. This study revealed the defense mechanisms employed by Vetiver grass against metal stress that include: chelation of toxic metals by phenolics, glutathione S-tranferase, and low molecular weight thiols; sequestration and accumulation of metals within the cell wall that was revealed by the scanning electron microscopy that showed closure of stomata and thickened cell wall and was confirmed by high content of cell wall bound phenolics. Metal induced reactive oxygen species are reduced or eliminated by catalase, superoxide dismutase and peroxidase dismutase.

  5. Comparing the hydrology of grassed and cultivated catchments in the semi-arid Canadian prairies

    Science.gov (United States)

    van der Kamp, G.; Hayashi, M.; Gallén, D.

    2003-02-01

    At the St Denis National Wildlife Area in the prairie region of southern Saskatchewan, Canada, water levels in wetlands have been monitored since 1968. In 1980 and 1983 a total of about one-third of the 4 km2 area was converted from cultivation to an undisturbed cover of brome grass. A few years after this conversion all the wetlands within the area of grass dried out; they have remained dry since, whereas wetlands in adjacent cultivated lands have held water as before. Field measurements show that introduction of undisturbed grass reduces water input to the wetlands mainly through a combination of efficient snow trapping and enhanced infiltration into frozen soil. In winter, the tall brome grass traps most of the snowfall, whereas in the cultivated fields more wind transport of snow occurs, especially for short stubble and fallow fields. Single-ring infiltration tests were conducted during snowmelt, while the soil was still frozen, and again in summer. The infiltrability of the frozen soil in the grassland is high enough to absorb most or all of the snowmelt, whereas in the cultivated fields the infiltration into the frozen soil is limited and significant runoff occurs. In summer, the infiltrability increases for the cultivated fields, but the grassland retains a much higher infiltrability than the cultivated land. The development of enhanced infiltrability takes several years after the conversion from cultivation to grass, and is likely due to the gradual development of macropores, such as root holes, desiccation cracks, and animal burrows.

  6. Invasion of non-native grasses causes a drop in soil carbon storage in California grasslands

    Energy Technology Data Exchange (ETDEWEB)

    Koteen, Laura E; Harte, John [Energy and Resources Group, 310 Barrows Hall, University of California, Berkeley, CA 94720 (United States); Baldocchi, Dennis D, E-mail: lkoteen@berkeley.edu [Department of Environmental Science, Policy and Management, 137 Mulford Hall, University of California, Berkeley, CA 94720 (United States)

    2011-10-15

    Vegetation change can affect the magnitude and direction of global climate change via its effect on carbon cycling among plants, the soil and the atmosphere. The invasion of non-native plants is a major cause of land cover change, of biodiversity loss, and of other changes in ecosystem structure and function. In California, annual grasses from Mediterranean Europe have nearly displaced native perennial grasses across the coastal hillsides and terraces of the state. Our study examines the impact of this invasion on carbon cycling and storage at two sites in northern coastal California. The results suggest that annual grass invasion has caused an average drop in soil carbon storage of 40 Mg/ha in the top half meter of soil, although additional mechanisms may also contribute to soil carbon losses. We attribute the reduction in soil carbon storage to low rates of net primary production in non-native annuals relative to perennial grasses, a shift in rooting depth and water use to primarily shallow sources, and soil respiratory losses in non-native grass soils that exceed production rates. These results indicate that even seemingly subtle land cover changes can significantly impact ecosystem functions in general, and carbon storage in particular.

  7. Invasion of non-native grasses causes a drop in soil carbon storage in California grasslands

    Science.gov (United States)

    Koteen, Laura E.; Baldocchi, Dennis D.; Harte, John

    2011-10-01

    Vegetation change can affect the magnitude and direction of global climate change via its effect on carbon cycling among plants, the soil and the atmosphere. The invasion of non-native plants is a major cause of land cover change, of biodiversity loss, and of other changes in ecosystem structure and function. In California, annual grasses from Mediterranean Europe have nearly displaced native perennial grasses across the coastal hillsides and terraces of the state. Our study examines the impact of this invasion on carbon cycling and storage at two sites in northern coastal California. The results suggest that annual grass invasion has caused an average drop in soil carbon storage of 40 Mg/ha in the top half meter of soil, although additional mechanisms may also contribute to soil carbon losses. We attribute the reduction in soil carbon storage to low rates of net primary production in non-native annuals relative to perennial grasses, a shift in rooting depth and water use to primarily shallow sources, and soil respiratory losses in non-native grass soils that exceed production rates. These results indicate that even seemingly subtle land cover changes can significantly impact ecosystem functions in general, and carbon storage in particular.

  8. Invasion of non-native grasses causes a drop in soil carbon storage in California grasslands

    International Nuclear Information System (INIS)

    Koteen, Laura E; Harte, John; Baldocchi, Dennis D

    2011-01-01

    Vegetation change can affect the magnitude and direction of global climate change via its effect on carbon cycling among plants, the soil and the atmosphere. The invasion of non-native plants is a major cause of land cover change, of biodiversity loss, and of other changes in ecosystem structure and function. In California, annual grasses from Mediterranean Europe have nearly displaced native perennial grasses across the coastal hillsides and terraces of the state. Our study examines the impact of this invasion on carbon cycling and storage at two sites in northern coastal California. The results suggest that annual grass invasion has caused an average drop in soil carbon storage of 40 Mg/ha in the top half meter of soil, although additional mechanisms may also contribute to soil carbon losses. We attribute the reduction in soil carbon storage to low rates of net primary production in non-native annuals relative to perennial grasses, a shift in rooting depth and water use to primarily shallow sources, and soil respiratory losses in non-native grass soils that exceed production rates. These results indicate that even seemingly subtle land cover changes can significantly impact ecosystem functions in general, and carbon storage in particular.

  9. Community

    Science.gov (United States)

    stability Science & Innovation Collaboration Careers Community Environment Science & Innovation Recruitment Events Community Commitment Giving Campaigns, Drives Economic Development Employee Funded neighbor pledge: contribute to quality of life in Northern New Mexico through economic development

  10. Effect of Tylenchorhynchus robustoides on Growth of Buffalo Grass and Western Wheatgrass.

    Science.gov (United States)

    Smolik, J D

    1982-10-01

    Tylenchorhynchus robustoides reduced (P = 0.05) growth of Agropyron smithii (western wheatgrass) at soil temperatures of 20, 25, 30, and 35 C. Growth reduction increased with increasing soil temperatures. Highest populations of T. robustoides were recovered at 25 and 30 C. Clipping weights of Buchloe dactyloides (buffalo grass) were reduced at 25 and 30 C; however, root/crown weights were reduced at 15, 20, 30, and 35 C in nematode infested vs. noninfested soil. Reproduction of T. robustoides was greater at 25, 30, and 35 C than at 20 C on B. dactyloides. In a greenhouse study, T. robustoides reduced clipping and root/crown weights of both grasses 24-64%.

  11. Shoot and root biomass allocation and competitive hierarchies of ...

    African Journals Online (AJOL)

    Shoot and root biomass allocation and competitive hierarchies of four South African grass species on light, soil resources and cutting gradients. ... Aristida junciformis, produced nearly double the biomass of taller species such as Hyparrhenia hirta and Eragrostis curvula in the low-nutrient treatments, with the reverse being ...

  12. In vitro antioxidant activity of Vetiveria zizanioides root extract ...

    African Journals Online (AJOL)

    Vetiveria zizanioides belonging to the family Gramineae, is a densely tufted grass which is widely used as a traditional plant for aromatherapy, to relieve stress, anxiety, nervous tension and insomnia. In this regard, the roots of V. zizanioides was extracted with ethanol and used for the evaluation of various in vitro antioxidant ...

  13. Pretreatment of grass waste using combined ionizing radiation-acid treatment for enhancing fermentative hydrogen production.

    Science.gov (United States)

    Yang, Guang; Wang, Jianlong

    2018-05-01

    In this study, the combined ionizing radiation-acid pretreatment process was firstly applied to enhance hydrogen fermentation of grass waste. Results showed that the combined pretreatment synergistically enhanced hydrogen fermentation of grass waste. The SCOD and soluble polysaccharide contents of grass waste increased by 1.6 and 2.91 times after the combined pretreatment, respectively. SEM observation and crystallinity test showed the combined pretreatment effectively disrupted the grass structure. Owing to the more favorable substrate conditions, the hydrogen yield achieved 68 mL/g-dry grass added after the combined pretreatment, which was 161.5%, 112.5% and 28.3% higher than those from raw, ionizing radiation pretreated and acid pretreated grass waste, respectively. The VS removal also increased from 13.9% to 25.6% by the combined pretreatment. Microbial community analysis showed that the abundance of dominant hydrogen producing genus Clostridium sensu stricto 1 increased from 37.9% to 69.4% after the combined pretreatment, which contributed to more efficient hydrogen fermentation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. First report of the root-knot nematode Meloidogyne minor on turfgrass in Belgium

    NARCIS (Netherlands)

    Viaene, N.; Wiseborn, D.B.; Karssen, G.

    2007-01-01

    The root-knot nematode, Meloidogyne minor, was described during 2004 after it was found on potato roots in a field in the Netherlands and in golf courses in England, Wales, and Ireland (2). Since it is associated with yellow patch disease in turf grass and causes deformation of potato tubers (2), it

  15. Interaction between a fungal endophyte and root herbivores of Ammophila arenaria

    NARCIS (Netherlands)

    Hol, W.H.G.; de la Peña, E.; Moens, M.; Cook, R.

    2007-01-01

    The effect of an endophytic fungus (Acremonium strictum) on plant-growth related parameters of marram grass (Ammophila arenaria), and its potential as a protective agent against root herbivores (Pratylenchus dunensis and Pratylenchus penetrans, root-lesion nematodes) was investigated in two

  16. Selective pressures on C4 photosynthesis evolution in grasses through the lens of optimality

    OpenAIRE

    Akcay, Erol; Zhou, Haoran; Helliker, Brent

    2016-01-01

    CO2, temperature, water availability and light intensity were potential selective pressures to propel the initial evolution and global expansion of C4 photosynthesis in grasses. To tease apart the primary selective pressures along the evolutionary trajectory, we coupled photosynthesis and hydraulics models and optimized photosynthesis over stomatal resistance and leaf/fine-root allocation. We also examined the importance of nitrogen reallocation from the dark to the light reactions. Our resul...

  17. Effect of Tylenchorhynchus robustoides on Growth of Buffalo Grass and Western Wheatgrass

    OpenAIRE

    Smolik, J. D.

    1982-01-01

    Tylenchorhynchus robustoides reduced (P = 0.05) growth of Agropyron smithii (western wheatgrass) at soil temperatures of 20, 25, 30, and 35 C. Growth reduction increased with increasing soil temperatures. Highest populations of T. robustoides were recovered at 25 and 30 C. Clipping weights of Buchloe dactyloides (buffalo grass) were reduced at 25 and 30 C; however, root/crown weights were reduced at 15, 20, 30, and 35 C in nematode infested vs. noninfested soil. Reproduction of T. robustoides...

  18. Grass leaves as potential hominin dietary resources.

    Science.gov (United States)

    Paine, Oliver C C; Koppa, Abigale; Henry, Amanda G; Leichliter, Jennifer N; Codron, Daryl; Codron, Jacqueline; Lambert, Joanna E; Sponheimer, Matt

    2018-04-01

    Discussions about early hominin diets have generally excluded grass leaves as a staple food resource, despite their ubiquity in most early hominin habitats. In particular, stable carbon isotope studies have shown a prevalent C 4 component in the diets of most taxa, and grass leaves are the single most abundant C 4 resource in African savannas. Grass leaves are typically portrayed as having little nutritional value (e.g., low in protein and high in fiber) for hominins lacking specialized digestive systems. It has also been argued that they present mechanical challenges (i.e., high toughness) for hominins with bunodont dentition. Here, we compare the nutritional and mechanical properties of grass leaves with the plants growing alongside them in African savanna habitats. We also compare grass leaves to the leaves consumed by other hominoids and demonstrate that many, though by no means all, compare favorably with the nutritional and mechanical properties of known primate foods. Our data reveal that grass leaves exhibit tremendous variation and suggest that future reconstructions of hominin dietary ecology take a more nuanced approach when considering grass leaves as a potential hominin dietary resource. Copyright © 2017. Published by Elsevier Ltd.

  19. Root (Botany)

    Science.gov (United States)

    Robert R. Ziemer

    1981-01-01

    Plant roots can contribute significantly to the stability of steep slopes. They can anchor through the soil mass into fractures in bedrock, can cross zones of weakness to more stable soil, and can provide interlocking long fibrous binders within a weak soil mass. In deep soil, anchoring to bedrock becomes negligible, and lateral reinforcement predominates

  20. Grass Biomethane for Agriculture and Energy

    DEFF Research Database (Denmark)

    Korres, N.E.; Thamsiriroj, T.; Smith, B.

    2011-01-01

    have advanced the role of grassland as a renewable source of energy in grass biomethane production with various environmental and socio-economic benefits. It is underlined that the essential question whether the gaseous biofuel meets the EU sustainability criteria of 60% greenhouse gas emission savings...... by 2020 can be met since savings up to 89.4% under various scenarios can be achieved. Grass biomethane production compared to other liquid biofuels either when these are produced by indigenous of imported feedstocks is very promising. Grass biomethane, given the mature and well known technology...

  1. Automated Root Tracking with "Root System Analyzer"

    Science.gov (United States)

    Schnepf, Andrea; Jin, Meina; Ockert, Charlotte; Bol, Roland; Leitner, Daniel

    2015-04-01

    Crucial factors for plant development are water and nutrient availability in soils. Thus, root architecture is a main aspect of plant productivity and needs to be accurately considered when describing root processes. Images of root architecture contain a huge amount of information, and image analysis helps to recover parameters describing certain root architectural and morphological traits. The majority of imaging systems for root systems are designed for two-dimensional images, such as RootReader2, GiA Roots, SmartRoot, EZ-Rhizo, and Growscreen, but most of them are semi-automated and involve mouse-clicks in each root by the user. "Root System Analyzer" is a new, fully automated approach for recovering root architectural parameters from two-dimensional images of root systems. Individual roots can still be corrected manually in a user interface if required. The algorithm starts with a sequence of segmented two-dimensional images showing the dynamic development of a root system. For each image, morphological operators are used for skeletonization. Based on this, a graph representation of the root system is created. A dynamic root architecture model helps to determine which edges of the graph belong to an individual root. The algorithm elongates each root at the root tip and simulates growth confined within the already existing graph representation. The increment of root elongation is calculated assuming constant growth. For each root, the algorithm finds all possible paths and elongates the root in the direction of the optimal path. In this way, each edge of the graph is assigned to one or more coherent roots. Image sequences of root systems are handled in such a way that the previous image is used as a starting point for the current image. The algorithm is implemented in a set of Matlab m-files. Output of Root System Analyzer is a data structure that includes for each root an identification number, the branching order, the time of emergence, the parent

  2. Physical root-soil interactions

    Science.gov (United States)

    Kolb, Evelyne; Legué, Valérie; Bogeat-Triboulot, Marie-Béatrice

    2017-12-01

    Plant root system development is highly modulated by the physical properties of the soil and especially by its mechanical resistance to penetration. The interplay between the mechanical stresses exerted by the soil and root growth is of particular interest for many communities, in agronomy and soil science as well as in biomechanics and plant morphogenesis. In contrast to aerial organs, roots apices must exert a growth pressure to penetrate strong soils and reorient their growth trajectory to cope with obstacles like stones or hardpans or to follow the tortuous paths of the soil porosity. In this review, we present the main macroscopic investigations of soil-root physical interactions in the field and combine them with simple mechanistic modeling derived from model experiments at the scale of the individual root apex.

  3. Genome sequence analysis of the model grass Brachypodium distachyon: insights into grass genome evolution

    Energy Technology Data Exchange (ETDEWEB)

    Schulman, Al

    2009-08-09

    Three subfamilies of grasses, the Erhardtoideae (rice), the Panicoideae (maize, sorghum, sugar cane and millet), and the Pooideae (wheat, barley and cool season forage grasses) provide the basis of human nutrition and are poised to become major sources of renewable energy. Here we describe the complete genome sequence of the wild grass Brachypodium distachyon (Brachypodium), the first member of the Pooideae subfamily to be completely sequenced. Comparison of the Brachypodium, rice and sorghum genomes reveals a precise sequence- based history of genome evolution across a broad diversity of the grass family and identifies nested insertions of whole chromosomes into centromeric regions as a predominant mechanism driving chromosome evolution in the grasses. The relatively compact genome of Brachypodium is maintained by a balance of retroelement replication and loss. The complete genome sequence of Brachypodium, coupled to its exceptional promise as a model system for grass research, will support the development of new energy and food crops

  4. Grass survey of the Itremo Massif records endemic central highland ...

    African Journals Online (AJOL)

    Twenty species are endemic to the central highlands, and a further 1 4 species are restricted to Madagascar. Five ecological groups of grasses were identified in the Itremo Massif: shade species in gallery forests, open wet area species, fire grasses, anthropogenic disturbance associated grasses and rock-dwelling grasses.

  5. Spatial patterns of grasses and shrubs in an arid grassland environment

    Science.gov (United States)

    In the Chihuahuan Desert of Mexico and New Mexico, shrub invasion is a common problem, and once-abundant grassland ecosystems are being replaced by shrub-dominated habitat. The spatial arrangement of grasses and shrubs in these arid grasslands can provide better insight into community dynamics and c...

  6. Differences in breeding bird assemblages related to reed canary grass cover cover and forest structure on the Upper Mississippi River

    Science.gov (United States)

    Kirsch, Eileen M.; Gray, Brian R.

    2017-01-01

    Floodplain forest of the Upper Mississippi River provides habitat for an abundant and diverse breeding bird community. However, reed canary grass Phalaris arundinacea invasion is a serious threat to the future condition of this forest. Reed canary grass is a well-known aggressive invader of wetland systems in the northern tier states of the conterminous United States. Aided by altered flow regimes and nutrient inputs from agriculture, reed canary grass has formed dense stands in canopy gaps and forest edges, retarding tree regeneration. We sampled vegetation and breeding birds in Upper Mississippi River floodplain forest edge and interior areas to 1) measure reed canary grass cover and 2) evaluate whether the breeding bird assemblage responded to differences in reed canary grass cover. Reed canary grass was found far into forest interiors, and its cover was similar between interior and edge sites. Bird assemblages differed between areas with more or less reed canary grass cover (.53% cover breakpoint). Common yellowthroat Geothlypis trichas, black-capped chickadee Parus atricapillus, and rose-breasted grosbeak Pheucticus ludovicianus were more common and American redstart Setophaga ruticilla, great crested flycatcher Myiarchus crinitus, and Baltimore oriole Icterus galbula were less common in sites with more reed canary grass cover. Bird diversity and abundance were similar between sites with different reed canary grass cover. A stronger divergence in bird assemblages was associated with ground cover ,15%, resulting from prolonged spring flooding. These sites hosted more prothonotary warbler Protonotaria citrea, but they had reduced bird abundance and diversity compared to other sites. Our results indicate that frequently flooded sites may be important for prothonotary warblers and that bird assemblages shift in response to reed canary grass invasion.

  7. Pampas Grass - Orange Co. [ds351

    Data.gov (United States)

    California Natural Resource Agency — This dataset provides the known distribution of pampas grass (Cortaderia selloana) in southern Orange County. The surveys were conducted from May to June, 2007 and...

  8. Tree-grass interactions in savannas

    CSIR Research Space (South Africa)

    Scholes, RJ

    1997-01-01

    Full Text Available Savannas occur where trees and grasses interact to create a biome that is neither grassland nor forest. Woody and gramineous plants interact by many mechanisms, some negative (competition) and some positive (facilitation). The strength and sign...

  9. POTENTIALS OF AGRICULTURAL WASTE AND GRASSES IN ...

    African Journals Online (AJOL)

    Shima

    Potentials of some agricultural waste and grasses were investigated. ... to education, printing, publishing and ... technical form, paper is an aqueous deposit ..... Period of. Soaking. Overnight. Overnight. Overnight. Overnight. Overnight.

  10. Grasses for energy production: hydrological guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Hall, R.L.

    2003-07-01

    This report provides hydrological guidelines for growers, land and water resource managers, environmental groups and other parties interested in utilising grasses for energy production. The aim of the report is to help interested parties decide if a location is suitable for planting energy grasses by considering whether potential hydrological impacts will have an adverse effect on crop productivity and yield. The guidelines consider: the water use of energy grasses compared with other crops; the factors governing water use; the water requirements for a productive crop; and the likely impacts on the availability and quantity of water. The report points out that there are still gaps in our knowledge of the processes controlling the water use and growth of energy grasses and notes that, in some situations, there will be considerable uncertainty in predictions of water use and the magnitude of the associated hydrological impacts.

  11. Imaging spectroscopy for characterisation of grass swards

    NARCIS (Netherlands)

    Schut, A.G.T.

    2003-01-01

    Keywords: Imaging spectroscopy, imaging spectrometry, remote sensing, reflection, reflectance, grass sward, white clover, recognition, characterisation, ground cover, growth monitoring, stress detection, heterogeneity quantification

    The potential of imaging spectroscopy as a tool for

  12. Karl Konrad Grass jumalainimeste uurijana / Alar Laats

    Index Scriptorium Estoniae

    Laats, Alar

    2006-01-01

    Karl Konrad Grass oli 19. sajandil Dorpati keiserliku ülikooli usuteaduskonna Uue Testamendi õppejõud, kes tegeles hobi korras idakristluse (vene sektid) uurimisega. Tema peateoseks on uurimus "Die russischen Sekten". Ettekanne konverentsil 15.-16. aprill 2005. a.

  13. Community.

    Science.gov (United States)

    Grauer, Kit, Ed.

    1995-01-01

    Art in context of community is the theme of this newsletter. The theme is introduced in an editorial "Community-Enlarging the Definition" (Kit Grauer). Related articles include: (1) "The Children's Bridge is not Destroyed: Heart in the Middle of the World" (Emil Robert Tanay); (2) "Making Bridges: The Sock Doll…

  14. Interspecific nutrient transfer in a tallgrass prairie plant community

    International Nuclear Information System (INIS)

    Walter, L.E.F.; Hartnett, D.C.; Hetrick, B.A.D.; Schwab, A.P.

    1996-01-01

    Interplant nutrient transfer may be an important ecological process in grasslands, and may significantly influence plant neighborhood interactions. We investigated the potential for phosphorus transfer between the dominant grass Andropogon gerardii and several neighboring plant species in tallgrass prairie via a field 32PO4 labelling experiment. The mean amount of 32P received from donor shoots differed significantly among neighboring species and decreased with increasing distance from the donor. In general, forbs and cool-season C3 grasses received more labelled 32P than warm-season C4 grasses. Phosphorus transfer occurred over distances up to 0.5 m. The effects of species and distance on movement of phosphorus changed with increasing time after labelling. The relative mass of receiver and donor shoots did not affect amounts of 32P transfer. A benomyl fungicide treatment, applied to suppress mycorrhizal activity, likely did not affect existing vegetative hyphae and did not affect the amount of 32P transferred. These studies demonstrate that: (1) phosphorus is transferred among neighboring species in tallgrass prairie plant communities, (2) phosphorus may be transferred over significantly greater distances than reported in other grasslands, and (3) there is differential transfer among co-occurring species. Hypothesized mechanisms accounting for these patterns in tallgrass prairie include mycorrhizal hyphal interconnections and/or extensive and differential root and rhizosphere overlap among neighboring species

  15. Productive and morphogenetic responses of buffel grass at different air temperatures and CO2 concentrations

    Directory of Open Access Journals (Sweden)

    Roberta Machado Santos

    2014-08-01

    Full Text Available The objective of the present trial was to evaluate the productive and morphogenetic characteristics of buffel grass subjected to different air temperatures and CO2 concentrations. Three cultivars of buffel grass (Biloela, Aridus and West Australian were compared. Cultivars were grown in growth chambers at three temperatures (day/night: 26/20, 29/23, and 32/26 °C, combined with two concentrations of CO2: 370 and 550 µmol mol-1. The experimental design was completely randomized, in a 3 × 3 × 2 factorial arrangement with three replications. There were interactions between buffel grass cultivars and air temperatures on leaf elongation rate (LER, leaf appearance rate (LAR, leaf lifespan (LL and senescence rate (SR, whereas cultivars vs. carbon dioxide concentration affected forage mass (FM, root mass (RM, shoot/root ratio, LL and SR. Leaf elongation rate and SR were higher as the air temperature was raised. Increasing air temperature also promoted an increase in LAR, except for West Australian. High CO2 concentration provided greater SR of plants, except for Biloela. Cultivar West Australian had higher FM in relation to Biloela and Aridus when the CO2 concentration was increased to 550 µmol mol-1. West Australian was the only cultivar that responded with more forage mass when it was exposed to higher carbon dioxide concentrations, whereas Aridus had depression in forage mass. The increase in air temperatures affects morphogenetic responses of buffel grass, accelerating its vegetative development without increasing forage mass. Elevated carbon dioxide concentration changes productive responses of buffel grass.

  16. Aboveground endophyte affects root volatile emission and host plant selection of a belowground insect.

    Science.gov (United States)

    Rostás, Michael; Cripps, Michael G; Silcock, Patrick

    2015-02-01

    Plants emit specific blends of volatile organic compounds (VOCs) that serve as multitrophic, multifunctional signals. Fungi colonizing aboveground (AG) or belowground (BG) plant structures can modify VOC patterns, thereby altering the information content for AG insects. Whether AG microbes affect the emission of root volatiles and thus influence soil insect behaviour is unknown. The endophytic fungus Neotyphodium uncinatum colonizes the aerial parts of the grass hybrid Festuca pratensis × Lolium perenne and is responsible for the presence of insect-toxic loline alkaloids in shoots and roots. We investigated whether endophyte symbiosis had an effect on the volatile emission of grass roots and if the root herbivore Costelytra zealandica was able to recognize endophyte-infected plants by olfaction. In BG olfactometer assays, larvae of C. zealandica were more strongly attracted to roots of uninfected than endophyte-harbouring grasses. Combined gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry revealed that endophyte-infected roots emitted less VOCs and more CO2. Our results demonstrate that symbiotic fungi in plants may influence soil insect distribution by changing their behaviour towards root volatiles. The well-known defensive mutualism between grasses and Neotyphodium endophytes could thus go beyond bioactive alkaloids and also confer protection by being chemically less apparent for soil herbivores.

  17. Treatment with grass allergen peptides improves symptoms of grass pollen-induced allergic rhinoconjunctivitis.

    Science.gov (United States)

    Ellis, Anne K; Frankish, Charles W; O'Hehir, Robyn E; Armstrong, Kristen; Steacy, Lisa; Larché, Mark; Hafner, Roderick P

    2017-08-01

    Synthetic peptide immunoregulatory epitopes are a new class of immunotherapy to treat allergic rhinoconjunctivitis (ARC). Grass allergen peptides, comprising 7 synthetic T-cell epitopes derived from Cyn d 1, Lol p 5, Dac g 5, Hol l 5, and Phl p 5, is investigated for treatment of grass pollen-induced ARC. We sought to evaluate the efficacy, safety, and tolerability of intradermally administered grass allergen peptides. A multicenter, randomized, double-blind, placebo-controlled study evaluated 3 regimens of grass allergen peptides versus placebo in patients with grass pollen-induced allergy (18-65 years). After a 4-day baseline challenge to rye grass in the environmental exposure unit (EEU), subjects were randomized to receive grass allergen peptides at 6 nmol at 2-week intervals for a total of 8 doses (8x6Q2W), grass allergen peptides at 12 nmol at 4-week intervals for a total of 4 doses (4x12Q4W), or grass allergen peptides at 12 nmol at 2-week intervals for a total of 8 doses (8x12Q2W) or placebo and treated before the grass pollen season. The primary efficacy end point was change from baseline in total rhinoconjunctivitis symptom score across days 2 to 4 of a 4-day posttreatment challenge (PTC) in the EEU after the grass pollen season. Secondary efficacy end points and safety were also assessed. Two hundred eighty-two subjects were randomized. Significantly greater improvement (reduction of total rhinoconjunctivitis symptom score from baseline to PTC) occurred across days 2 to 4 with grass allergen peptide 8x6Q2W versus placebo (-5.4 vs -3.8, respectively; P = .0346). Greater improvement at PTC also occurred for grass allergen peptide 8x6Q2W versus placebo (P = .0403) in patients with more symptomatic ARC. No safety signals were detected. Grass allergen peptide 8x6Q2W significantly improved ARC symptoms after rye grass allergen challenge in an EEU with an acceptable safety profile. Copyright © 2017 American Academy of Allergy, Asthma & Immunology

  18. Cell wall composition throughout development for the model grass Brachypodium distanchyon

    Directory of Open Access Journals (Sweden)

    David eRancour

    2012-12-01

    Full Text Available Temperate perennial grasses are important worldwide as a livestock nutritive energy source and a potential feedstock for lignocellulosic biofuel production. The annual temperate grass Brachypodium distanchyon has been championed as a useful model system to facilitate biological research in agriculturally important temperate forage grasses based on phylogenetic relationships. To physically corroborate genetic predictions, we determined the chemical composition profiles of organ-specific cell walls throughout the development of two common diploid accessions of Brachypodium distanchyon, Bd21-3 and Bd21. Chemical analysis was performed on cell walls isolated from distinct organs (i.e. leaves, sheaths, stems and roots at three developmental stages of 1 12-day seedling, 2 vegetative-to-reproductive transition, and 3 mature seed-fill. In addition, we have included cell wall analysis of embryonic callus used for genetic transformations. Composition of cell walls based on components lignin, hydroxycinnamates, uronosyls, neutral sugars, and protein suggests that Brachypodium distanchyon is similar chemically to agriculturally important forage grasses. There were modest compositional differences in hydroxycinnamate profiles between accessions Bd21-3 and Bd21. In addition, when compared to agronomical important C3 grasses, more mature Brachypodium stem cell walls have a relative increase in glucose of 48% and a decrease in lignin of 36%. Though differences exists between Brachypodium and agronomical important C3 grasses, Brachypodium distanchyon should be still a useful model system for genetic manipulation of cell wall composition to determine the impact upon functional characteristics such as rumen digestibility or energy conversion efficiency for bioenergy production.

  19. Cell wall composition throughout development for the model grass Brachypodium distachyon

    Science.gov (United States)

    Rancour, David M.; Marita, Jane M.; Hatfield, Ronald D.

    2012-01-01

    Temperate perennial grasses are important worldwide as a livestock nutritive energy source and a potential feedstock for lignocellulosic biofuel production. The annual temperate grass Brachypodium distachyon has been championed as a useful model system to facilitate biological research in agriculturally important temperate forage grasses based on phylogenetic relationships. To physically corroborate genetic predictions, we determined the chemical composition profiles of organ-specific cell walls throughout the development of two common diploid accessions of Brachypodium distachyon, Bd21-3 and Bd21. Chemical analysis was performed on cell walls isolated from distinct organs (i.e., leaves, sheaths, stems, and roots) at three developmental stages of (1) 12-day seedling, (2) vegetative-to-reproductive transition, and (3) mature seed fill. In addition, we have included cell wall analysis of embryonic callus used for genetic transformations. Composition of cell walls based on components lignin, hydroxycinnamates, uronosyls, neutral sugars, and protein suggests that Brachypodium distachyon is similar chemically to agriculturally important forage grasses. There were modest compositional differences in hydroxycinnamate profiles between accessions Bd21-3 and Bd21. In addition, when compared to agronomical important C3 grasses, more mature Brachypodium stem cell walls have a relative increase in glucose of 48% and a decrease in lignin of 36%. Though differences exist between Brachypodium and agronomical important C3 grasses, Brachypodium distachyon should be still a useful model system for genetic manipulation of cell wall composition to determine the impact upon functional characteristics such as rumen digestibility or energy conversion efficiency for bioenergy production. PMID:23227028

  20. Root colonization of bait plants by indigenous arbuscular mycorrhizal fungal communities is not a suitable indicator of agricultural land-use legacy

    Czech Academy of Sciences Publication Activity Database

    Jansa, Jan; Řezáčová, Veronika; Šmilauer, P.; Oberholzer, H.-R.; Egli, S.

    2016-01-01

    Roč. 231, SEPTEMBER (2016), s. 310-319 ISSN 0167-8809 R&D Projects: GA ČR GAP504/12/1665; GA MŠk(CZ) LK11224 Institutional support: RVO:61388971 Keywords : Arbuscular mycorrhiza * Geography * Root colonization Subject RIV: EE - Microbiology, Virology Impact factor: 4.099, year: 2016

  1. Assessment of the relationship between geologic origin of soil, rhizobacterial community composition and soil receptivity to tobacco black root rot in Savoie region (France)

    Czech Academy of Sciences Publication Activity Database

    Almario, J.; Kyselková, Martina; Kopecký, J.; Ságová-Marečková, M.; Muller, D.; Grundmann, G.L.; Moënne-Loccoz, Y.

    2013-01-01

    Roč. 371, 1/2 (2013), s. 397-408 ISSN 0032-079X Grant - others:MŚMT(CZ) ME09077 Institutional support: RVO:60077344 Keywords : suppressive soils * Thielaviopsis basicola * black root rot Subject RIV: EE - Microbiology, Virology Impact factor: 3.235, year: 2013

  2. Effect of bacterial inoculation, plant genotype and developmental stage on root-associated and endophytic bacterial communities in potato (Solanum tuberosum)

    NARCIS (Netherlands)

    Andreote, F.D.; Rocha, da U.N.; Araujo, W.L.; Azevedo, J.L.; Overbeek, van L.S.

    2010-01-01

    Beneficial bacteria interact with plants by colonizing the rhizosphere and roots followed by further spread through the inner tissues, resulting in endophytic colonization. The major factors contributing to these interactions are not always well understood for most bacterial and plant species. It is

  3. Locally Finite Root Supersystems

    OpenAIRE

    Yousofzadeh, Malihe

    2013-01-01

    We introduce the notion of locally finite root supersystems as a generalization of both locally finite root systems and generalized root systems. We classify irreducible locally finite root supersystems.

  4. DEPENDENCE OF GRASS COVER TAXONOMIC AND ECOLOGICAL STRUCTURE ON THE ANTHROPOGENIC IMPACT IN FOREST ECOSYSTEMS

    Directory of Open Access Journals (Sweden)

    N. V. Miroshnik

    2016-01-01

    Full Text Available Pine forests Chigirinsky Bor grow on fresh sod-podzolic soils formed on ancient alluvial deposits. Pine forests are characterized by stringent moisture regimes and constantly suffer from lack of productive moisture in soil.  Industrial development of Cherkasy in 60th years of ХХ century leaded air pollution and emissions of SO2, NOx, NH3, and dust. This contributed to significant negative influence on the surrounding forest ecosystems from enterprises of  Cherkassy industrial agglomeration. The grass cover in pine stands of Chigirinsky Bor transforms into xerophytic grasses and ruderal communities under the impact of negative biotic and abiotic factors. They are namely the anthropogenic violation of forest conditions, stands decline, recreational and industrial tree crowns understocking, xerophytic and heliophytic transformations of forest conditions. All the above mentioned caused strong ruderal and adventive transformation of grass cover. We registered the changes in nitrophilous plant spread regards the Cherkasy industrial agglomeration approaching which emits toxic with nitrogen-containing gases. Adventive and other non-forest species displace ferns and mosses, the ratio of ecomorfs is also changes due to increase of the quantity and development activation of annuals, xerophytic, ruderal, and nitrofil plants. The Asteraceae/Brassicaceae 3:1 ratio indicates significant anthropogenic violations in the region. We fixed the xerophytic, ruderal, and adventive transformation of grass cover in forest ecosystems. It is also founded the tendency of expanding the fraction of mesophilic plant species due to alterations in water regime (creation of Kremenchug reservoir and draining of floodplain Tyasmyn. When approaching the Cherkasy industrial agglomeration the grass cover degradation is clearly observed on the environmental profile. All this causes the forest ecosystem degradation and gradual loss of forest vegetation typical characteristics. We

  5. Nutritional value of cabbage and kikuyu grass as food for grass carp ...

    African Journals Online (AJOL)

    and digestibility coefficients were obtained for the protein, fibre, ash and fat contents of both ... Cabbage is a superior feed compared to grass for raising grass carp and a suitable low-cost alternative ... Materials and Methods ... from jumping out and was fitted with an air lift under- .... In: Aquatic weeds in South East Asia.

  6. Gene Expression Profiling of Grass Carp (Ctenopharyngodon idellus and Crisp Grass Carp

    Directory of Open Access Journals (Sweden)

    Ermeng Yu

    2014-01-01

    Full Text Available Grass carp (Ctenopharyngodon idellus is one of the most important freshwater fish that is native to China, and crisp grass carp is a kind of high value-added fishes which have higher muscle firmness. To investigate biological functions and possible signal transduction pathways that address muscle firmness increase of crisp grass carp, microarray analysis of 14,900 transcripts was performed. Compared with grass carp, 127 genes were upregulated and 114 genes were downregulated in crisp grass carp. Gene ontology (GO analysis revealed 30 GOs of differentially expressed genes in crisp grass carp. And strong correlation with muscle firmness increase of crisp grass carp was found for these genes from differentiation of muscle fibers and deposition of ECM, and also glycolysis/gluconeogenesis pathway and calcium metabolism may contribute to muscle firmness increase. In addition, a number of genes with unknown functions may be related to muscle firmness, and these genes are still further explored. Overall, these results had been demonstrated to play important roles in clarifying the molecular mechanism of muscle firmness increase in crisp grass carp.

  7. Different techniques to study rumen fermentation characteristics of maturing grass and grass silage

    NARCIS (Netherlands)

    Cone, J.W.; Gelder, van A.H.; Soliman, I.A.; Visser, de H.; Vuuren, van A.M.

    1999-01-01

    Grass samples were harvested during the 1993 growing season after a precut on April 27, 1993 and were stored frozen or left to ensile in 30-L buckets. Effects on chemical composition and fermentation kinetics of the maturation of the grass and of ensiling were investigated. Chemical composition and

  8. Analysis of the soil food web structure under grass and grass clover

    NARCIS (Netherlands)

    Eekeren, van N.J.M.; Smeding, F.W.; Vries, de F.T.; Bloem, J.

    2006-01-01

    The below ground biodiversity of soil organisms plays an important role in the functioning of the the soil ecosystem, and consequently the above ground plant production. The objective of this study is to investigate the effect of grass or grass-clover in combination with fertilisation on the soil

  9. Post-ruminal digestibility of crude protein from grass and grass silages in cows

    NARCIS (Netherlands)

    Cone, J.W.; Gelder, van A.H.; Mathijssen-Kamman, A.A.; Hindle, V.A.

    2006-01-01

    Grass samples were grown on a clay or sandy soil, fertilised with 150 or 300 kg N/ha per year, and harvested on different days during two consecutive growing seasons. The grass samples were stored frozen or ensiled after wilting to approximately 250 or 450 g DM/kg. The recoveries of crude protein

  10. Nitrogen removal and water microbiota in grass carp culture following supplementation with Bacillus licheniformis BSK-4.

    Science.gov (United States)

    Liang, Quan; Zhang, Xiaoping; Lee, Khui Hung; Wang, Yibing; Yu, Kan; Shen, Wenying; Fu, Luoqin; Shu, Miaoan; Li, Weifen

    2015-11-01

    This experiment was designed to study the effects of Bacillus licheniformis BSK-4 on nitrogen removal and microbial community structure in a grass carp (Ctenopharyngodon idellus) culture. The selected strain Bacillus licheniformis BSK-4 significantly decreased nitrite, nitrate and total nitrogen levels in water over an extended, whereas increased ammonia level. Pyrosequencing showed that Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes were dominant in grass carp culture water. Compared with the control group, the number of Proteobacteria and Firmicutes were increased, while Actinobacteria and Bacteroidetes decreased in treatment group. At the genus level, some genera, such as Bacillus, Prosthecobacter, Enterococcus, etc., appear only in the treatment, while many other genera exist only in the control group; Lactobacillus, Luteolibacter, Phenylobacterium, etc. were increased in treatment group compared to those in control group. As above, the results suggested that supplementation with B. licheniformis BSK-4 could remove some nitrogen and cause alterations of the microbial composition in grass carp water.

  11. Morphogenetic, structural and productive traits of buffel grass under different irrigation regimes

    Directory of Open Access Journals (Sweden)

    Maria Janiele Ferreira Coutinho

    2015-06-01

    Full Text Available The water restriction conditions in the Brazilian semiarid region are one of the most limiting factors to the establishment and yield of forage grasses. This study aimed to evaluate the effect of different irrigation regimes on morphogenetic, structural and productive traits of buffel grass. Arandomized blocks design, with five treatments and six replications, was used. Treatments consisted of five irrigation regimes, corresponding to the intervals of 2, 4, 6, 8 and 10 days. The traits analyzed were: leaf emergence rate, phyllochron, leaf and stem elongation rate, leaf senescence rate, final leaf length, number of green leaves per tiller, number of tillers, stem height, leaf/stem ratio, leaf area index, dry mass of green leaf and stem, dry mass of green, dead and total forage, root dry mass, dry mass and green dry mass/dead dry mass ratio. The final leaf length and dead forage dry mass were not affected by the irrigation regimes. The leaf/stem ratio followed a quadratic model, maintaining the value of 0.51 up to the irrigation regime of four days. The other morphological, structural and productive traits decreased linearly with increasing irrigation frequencies. The irrigation intervals promoted reductions in the morphological, structural and productive parameters of buffel grass, when grown under greenhouse conditions. The irrigation regime of 2 days stands out as the least restrictive to the development of buffel grass.

  12. Effects of processing phases on the quality of massai grass seeds

    Directory of Open Access Journals (Sweden)

    Lilian Faria de Melo

    Full Text Available ABSTRACT Massai grass is an important tropical forage grass. The harvested seeds upon being received by the company, are found to be contaminated with impurities which are removable by processing machines. This procedure is necessary to produce seeds of a quality level within standards established for commercialization and sowing purposes. The objective of this project was to evaluate the effects of processing phases on the physical and physiological quality of massai grass (Panicum maximum x P. infestum, cv. Massai seeds for commercialization purposes. Seeds were sampled before processing and after leaving the air and screen machine (upper and intermediary screens and bottom; first gravity table (drift, upper and intermediate spouts; treating machine; and second gravity table (upper, intermediate, and lower spouts. Seeds were evaluated as to water content, physical (purity and 1,000 seeds weight and physiological quality (germination, first count of germination, seedling vigor classification, accelerated aging, seedling emergence in the field, speed of emergence index, and primary root length, shoot length. Massai grass seeds had their physical and physiological qualities improved when they were processed by an air and screen machine and a gravity table. Seeds from the intermediate discharge spout of the first gravity table, after going through the air and screen machine, are those of with highest physiological potential. The seeds of this species do not need to be processed to fit the germination and purity standards when the national market is the goal.

  13. Comparison of arsenic uptake ability of barnyard grass and rice species for arsenic phytoremediation.

    Science.gov (United States)

    Sultana, Razia; Kobayashi, Katsuichiro; Kim, Ki-Hyun

    2015-01-01

    In this research, the relative performance in arsenic (As) remediation was evaluated among some barnyard grass and rice species under hydroponic conditions. To this end, four barnyard grass varieties and two rice species were selected and tested for their remediation potential of arsenic. The plants were grown for 2 weeks in As-rich solutions up to 10 mg As L(-1) to measure their tolerance to As and their uptake capabilities. Among the varieties of plants tested in all treatment types, BR-29 rice absorbed the highest amount of As in the root, while Nipponbare translocated the maximum amount of As in the shoot. Himetainubie barnyard grass produced the highest biomass, irrespective of the quantity of As in the solution. In all As-treated solutions, the maximum uptake of As was found in BR-29 followed by Choto shama and Himetainubie. In contrast, while the bioaccumulation factor was found to be the highest in Nipponbare followed by BR-29 and Himetainubie. The results suggest that both Choto shama and Himetainubie barnyard grass varieties should exhibit a great potential for As removal, while BR-29 and Nipponbare rice species are the best option for arsenic phytoremediation.

  14. Caracterización de la comunidad vegetal en una asociación de gramíneas mejoradas y Leucaena leucocephala cv.: Cunningham Characterization of the plant community in an association of improved grasses and Leucaena leucocephala cv.: Cunningham

    Directory of Open Access Journals (Sweden)

    Tania Sánchez

    2007-11-01

    Full Text Available En una vaquería de la Empresa Genética de Matanzas se realizó un estudio durante cinco años, con el objetivo de caracterizar el comportamiento de la comunidad vegetal en una asociación de gramíneas mejoradas y Leucaena leucocephala cv. Cunningham en condiciones comerciales. Se determinó la composición botánica del pastizal, la densidad de arbóreas, la disponibilidad de materia seca y los contenidos de MS, PB, Ca y P de las especies presentes en el sistema. La composición botánica del pastizal se caracterizó por un porcentaje de pastos mejorados superior al 50%, con predominio de Cynodon nlemfuensis cv. Jamaicano y Panicum maximum cv. Likoni; mientras que la leucaena mantuvo la densidad de plantas, como una adaptación a las condiciones del sistema. La disponibilidad de materia seca total fue superior a las 3 t/ha/rotación durante la etapa experimental. Se concluye que en la asociación de gramíneas mejoradas y L. leucocephala cv. Cunningham se presentó una alta disponibilidad de materia seca y persistencia del pastizal durante los cinco años del estudio, con valores de PB en las gramíneas mejoradas de 9,6-9,8% y en la leucaena de 25%, sin la aplicación de riego ni fertilizantes químicos, lo cual permitió atenuar las diferencias entre los períodos lluvioso y poco lluvioso.In a dairy of the Genetic Enterprise of Matanzas, a work was carried out for five years, with the objective of characterizing the performance of the plant community in an association of improved grasses and Leucaena leucocephala cv Cunningham under commercial conditions. The botanical composition of the pastureland, tree density, dry matter availability and DM, CP, Ca and P contents of the species present in the system were determined. The botanical composition of the pastureland was characterized by a percentage of improved pastures higher than 50%, with predominance of Cynodon nlemfuensis cv. Jamaicano and Panicum maximum cv. Likoni; while leucaena

  15. Diversity and Efficiency of Rhizobia Communities from Iron Mining Areas Using Cowpea as a Trap Plant

    Directory of Open Access Journals (Sweden)

    Jordana Luísa de Castro

    2017-08-01

    Full Text Available ABSTRACT Mining is an important economic activity. However, its impact on environment must be accessed, mainly on relevant processes for their sustainability. The objective of this study was to evaluate the diversity and efficiency of symbiotic nitrogen fixing bacterial communities in soils under different types of vegetation in the Quadrilátero Ferrífero: ironstone outcrops, Atlantic Forest, neotropical savanna, and a rehabilitated area revegetated with grass. Suspensions of soil samples collected under each type of vegetation were made in a saline solution to capture rhizobia communities that were then inoculated on cowpea [Vigna unguiculata (L. Walp.], which was used as a trap plant. The symbiotic efficiency of the communities was evaluated in a greenhouse experiment and the data obtained were correlated to the chemical and physical properties of the soils under each type of vegetation. At the end of the experiment, the bacteria present in the nodules were isolated to evaluate their diversity. The highest numbers of nodules occurred in the treatment inoculated with soil samples from rehabilitated area revegetated with grass and neotropical savanna vegetation, and the lowest numbers were observed in the treatment inoculated with soil samples from ironstone outcrops and Atlantic Forest. In relation to root dry matter, the treatment inoculated with soil samples from Neotropical savanah was superior to those inoculated with soil samples from the other areas; already, in relation to the shoot dry matter, no significant difference among the treatments was observed. The soil properties with the greatest influence on the microbial communities were Al3+ content, considered as high in the Atlantic Forest and neotropical savanna vegetation, as intermediate in the iron outcrops, and as very low in the rehabilitated area revegetated with grass; organic matter, considered as very high in the ironstone outcrops and neotropical savanna, as high in the

  16. How to study deep roots - and why it matters

    OpenAIRE

    Maeght, Jean-Luc; Rewald, B.; Pierret, Alain

    2013-01-01

    The drivers underlying the development of deep root systems, whether genetic or environmental, are poorly understood but evidence has accumulated that deep rooting could be a more widespread and important trait among plants than commonly anticipated from their share of root biomass. Even though a distinct classification of "deep roots" is missing to date, deep roots provide important functions for individual plants such as nutrient and water uptake but can also shape plant communities by hydr...

  17. Plastome Sequence Determination and Comparative Analysis for Members of the Lolium-Festuca Grass Species Complex

    Science.gov (United States)

    Hand, Melanie L.; Spangenberg, German C.; Forster, John W.; Cogan, Noel O. I.

    2013-01-01

    Chloroplast genome sequences are of broad significance in plant biology, due to frequent use in molecular phylogenetics, comparative genomics, population genetics, and genetic modification studies. The present study used a second-generation sequencing approach to determine and assemble the plastid genomes (plastomes) of four representatives from the agriculturally important Lolium-Festuca species complex of pasture grasses (Lolium multiflorum, Festuca pratensis, Festuca altissima, and Festuca ovina). Total cellular DNA was extracted from either roots or leaves, was sequenced, and the output was filtered for plastome-related reads. A comparison between sources revealed fewer plastome-related reads from root-derived template but an increase in incidental bacterium-derived sequences. Plastome assembly and annotation indicated high levels of sequence identity and a conserved organization and gene content between species. However, frequent deletions within the F. ovina plastome appeared to contribute to a smaller plastid genome size. Comparative analysis with complete plastome sequences from other members of the Poaceae confirmed conservation of most grass-specific features. Detailed analysis of the rbcL–psaI intergenic region, however, revealed a “hot-spot” of variation characterized by independent deletion events. The evolutionary implications of this observation are discussed. The complete plastome sequences are anticipated to provide the basis for potential organelle-specific genetic modification of pasture grasses. PMID:23550121

  18. Uptake of C14-atrazine by prairie grasses in a phytoremediation setting.

    Science.gov (United States)

    Khrunyk, Yuliya; Schiewer, Silke; Carstens, Keri L; Hu, Dingfei; Coats, Joel R

    2017-02-01

    Agrochemicals significantly contribute to environmental pollution. In the USA, atrazine is a widely used pesticide and commonly found in rivers, water systems, and rural wells. Phytoremediation can be a cost-effective means of removing pesticides from soil. The objective of this project was to investigate the ability of prairie grasses to remove atrazine. 14 C-labeled atrazine was added to sterilized sand and water/nutrient cultures, and the analysis was performed after 21 days. Switchgrass and big bluestem were promising species for phytoremediation, taking up about 40% of the applied [ 14 C] in liquid hydroponic cultures, and between 20% and 33% in sand cultures. Yellow Indiangrass showed low resistance to atrazine toxicity and low uptake of [ 14 C] atrazine in liquid hydroponic cultures. Atrazine degradation increased progressively from sand to roots and leaves. Most atrazine taken up by prairie grasses from sand culture was degraded to metabolites, which accounted for 60-80% of [ 14 C] detected in leaves. Deisopropylatrazine (DIA) was the main metabolite detected in sand and roots, whereas in leaves further metabolism took place, forming increased amounts of didealkylatrazine (DDA) and an unidentified metabolite. In conclusion, prairie grasses achieved high atrazine removal and degradation, showing a high potential for phytoremediation.

  19. Roots of symptom-free leguminous cover crop and living mulch species harbor diverse Fusarium communities that show highly variable aggressiveness on pea (Pisum sativum)

    Science.gov (United States)

    Baćanović-Šišić, Jelena; Karlovsky, Petr; Wittwer, Raphaël; Walder, Florian; Campiglia, Enio; Radicetti, Emanuele; Friberg, Hanna; Baresel, Jörg Peter; Finckh, Maria R.

    2018-01-01

    Leguminous cover crop and living mulch species show not only great potential for providing multiple beneficial services to agro-ecosystems, but may also present pathological risks for other crops in rotations through shared pathogens, especially those of the genus Fusarium. Disease severity on roots of subterranean clover, white clover, winter and summer vetch grown as cover crop and living mulch species across five European sites as well as the frequency, distribution and aggressiveness to pea of Fusarium spp. recovered from the roots were assessed in 2013 and 2014. Disease symptoms were very low at all sites. Nevertheless, out of 1480 asymptomatic roots, 670 isolates of 14 Fusarium spp. were recovered. The most frequently isolated species in both years from all hosts were F. oxysporum and F. avenaceum accounting for 69% of total isolation percentage. They were common at the Swiss, Italian and German sites, whereas at the Swedish site F. oxysporum dominated and F. avenaceum occurred only rarely. The agressiveness and effect on pea biomass were tested in greenhouse assays for 72 isolates of six Fusarium species. Isolates of F. avenaceum caused severe root rot symptoms with mean severity index (DI) of 82 and 74% mean biomass reduction compared to the non-inoculated control. Fusarium oxysporum and F. solani isolates were higly variable in agressiveness and their impact on pea biomass. DI varied between 15 and 50 and biomass changes relative to the non-inoculated control -40% to +10%. Isolates of F. tricinctum, F. acuminatum and F. equiseti were non to weakly agressive often enhancing pea biomass. This study shows that some of the major pea pathogens are characterized by high ecological plasticity and have the ability to endophytically colonize the hosts studied that thus may serve as inoculum reservoir for susceptible main legume grain crops such as pea. PMID:29444142

  20. Roots of symptom-free leguminous cover crop and living mulch species harbor diverse Fusarium communities that show highly variable aggressiveness on pea (Pisum sativum).

    Science.gov (United States)

    Šišić, Adnan; Baćanović-Šišić, Jelena; Karlovsky, Petr; Wittwer, Raphaël; Walder, Florian; Campiglia, Enio; Radicetti, Emanuele; Friberg, Hanna; Baresel, Jörg Peter; Finckh, Maria R

    2018-01-01

    Leguminous cover crop and living mulch species show not only great potential for providing multiple beneficial services to agro-ecosystems, but may also present pathological risks for other crops in rotations through shared pathogens, especially those of the genus Fusarium. Disease severity on roots of subterranean clover, white clover, winter and summer vetch grown as cover crop and living mulch species across five European sites as well as the frequency, distribution and aggressiveness to pea of Fusarium spp. recovered from the roots were assessed in 2013 and 2014. Disease symptoms were very low at all sites. Nevertheless, out of 1480 asymptomatic roots, 670 isolates of 14 Fusarium spp. were recovered. The most frequently isolated species in both years from all hosts were F. oxysporum and F. avenaceum accounting for 69% of total isolation percentage. They were common at the Swiss, Italian and German sites, whereas at the Swedish site F. oxysporum dominated and F. avenaceum occurred only rarely. The agressiveness and effect on pea biomass were tested in greenhouse assays for 72 isolates of six Fusarium species. Isolates of F. avenaceum caused severe root rot symptoms with mean severity index (DI) of 82 and 74% mean biomass reduction compared to the non-inoculated control. Fusarium oxysporum and F. solani isolates were higly variable in agressiveness and their impact on pea biomass. DI varied between 15 and 50 and biomass changes relative to the non-inoculated control -40% to +10%. Isolates of F. tricinctum, F. acuminatum and F. equiseti were non to weakly agressive often enhancing pea biomass. This study shows that some of the major pea pathogens are characterized by high ecological plasticity and have the ability to endophytically colonize the hosts studied that thus may serve as inoculum reservoir for susceptible main legume grain crops such as pea.

  1. Roots of symptom-free leguminous cover crop and living mulch species harbor diverse Fusarium communities that show highly variable aggressiveness on pea (Pisum sativum.

    Directory of Open Access Journals (Sweden)

    Adnan Šišić

    Full Text Available Leguminous cover crop and living mulch species show not only great potential for providing multiple beneficial services to agro-ecosystems, but may also present pathological risks for other crops in rotations through shared pathogens, especially those of the genus Fusarium. Disease severity on roots of subterranean clover, white clover, winter and summer vetch grown as cover crop and living mulch species across five European sites as well as the frequency, distribution and aggressiveness to pea of Fusarium spp. recovered from the roots were assessed in 2013 and 2014. Disease symptoms were very low at all sites. Nevertheless, out of 1480 asymptomatic roots, 670 isolates of 14 Fusarium spp. were recovered. The most frequently isolated species in both years from all hosts were F. oxysporum and F. avenaceum accounting for 69% of total isolation percentage. They were common at the Swiss, Italian and German sites, whereas at the Swedish site F. oxysporum dominated and F. avenaceum occurred only rarely. The agressiveness and effect on pea biomass were tested in greenhouse assays for 72 isolates of six Fusarium species. Isolates of F. avenaceum caused severe root rot symptoms with mean severity index (DI of 82 and 74% mean biomass reduction compared to the non-inoculated control. Fusarium oxysporum and F. solani isolates were higly variable in agressiveness and their impact on pea biomass. DI varied between 15 and 50 and biomass changes relative to the non-inoculated control -40% to +10%. Isolates of F. tricinctum, F. acuminatum and F. equiseti were non to weakly agressive often enhancing pea biomass. This study shows that some of the major pea pathogens are characterized by high ecological plasticity and have the ability to endophytically colonize the hosts studied that thus may serve as inoculum reservoir for susceptible main legume grain crops such as pea.

  2. Role of carbohydrate metabolism in grass tetany

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.K.; Madsen, F.C.; Lentz, D.E.; Hansard, S.L.

    1977-01-01

    Clinical hypomagnesemia is confined primarily to beef cattle in the United States but also occurs in dairy cattle in other countries, probably due to different management practices. During periods when grass tetany is likely, early vegetative temperate zone grasses are usually low in total readily available carbohydrates and magnesium but high in potassium and nitrogen. The tetany syndrome may include hypoglycemia and ketosis, suggesting an imbalance in intermediary energy metabolism. Many enzyme systems critical to cellular metabolism, including those which hydrolyze and transfer phosphate groups, are activated by Mg. Thus, by inference, Mg is required for normal glucose utilization, fat, protein, nucleic acid and coenzyme synthesis, muscle contraction, methyl group transfer, and sulfate, acetate, and formate activation. Numerous clinical and experimental studies suggest an intimate relationship between metabolism of Mg and that of carbohydrate, glucagon, and insulin. The objective is to review this literature and suggest ways in which these relationships might contribute to a chain of events leading to grass tetany.

  3. Controlling grass weeds on hard surfaces

    DEFF Research Database (Denmark)

    Rask, Anne Merete; Kristoffersen, Palle; Andreasen, Christian

    2012-01-01

    An experiment was conducted on a specially designed hard surface to study the impact of time interval between flaming treatments on the regrowth and flower production of two grass weeds. The goal of this experiment was to optimize the control of annual bluegrass and perennial ryegrass, both species...... that are very difficult to control without herbicides. Aboveground biomass from 72 plants per treatment was harvested and dry weights were recorded at regular intervals to investigate how the plants responded to flaming. Regrowth of the grasses was measured by harvesting aboveground biomass 2 wk after......, as they did not increase the reduction of aboveground biomass compared with the 7-d treatment interval. Knowledge on the regrowth of grass weeds after flaming treatments provided by this study can help improve recommendations given to road keepers and park managers for management on these weeds. Nomenclature...

  4. Biogas and Methane Yield from Rye Grass

    Directory of Open Access Journals (Sweden)

    Tomáš Vítěz

    2015-01-01

    Full Text Available Biogas production in the Czech Republic has expanded substantially, including marginal regions for maize cultivation. Therefore, there are increasingly sought materials that could partially replace maize silage, as a basic feedstock, while secure both biogas production and its quality.Two samples of rye grass (Lolium multiflorum var. westerwoldicum silage with different solids content 21% and 15% were measured for biogas and methane yield. Rye grass silage with solid content of 15% reached an average specific biogas yield 0.431 m3·kg−1 of organic dry matter and an average specific methane yield 0.249 m3·kg−1 of organic dry matter. Rye grass silage with solid content 21% reached an average specific biogas yield 0.654 m3·kg−1 of organic dry matter and an average specific methane yield 0.399 m3·kg−1 of organic dry matter.

  5. Root Differentiation of Agricultural Plant Cultivars and Proveniences Using FTIR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Nicole Legner

    2018-06-01

    Full Text Available The differentiation of roots of agricultural species is desired for a deeper understanding of the belowground root interaction which helps to understand the complex interaction in intercropping and crop-weed systems. The roots can be reliably differentiated via Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR. In two replicated greenhouse experiments, six pea cultivars, five oat cultivars as well as seven maize cultivars and five barnyard grass proveniences (n = 10 plants/cultivar or provenience were grown under controlled conditions. One root of each plant was harvested and five different root segments of each root were separated, dried and measured with FTIR-ATR spectroscopy. The results showed that, firstly, the root spectra of single pea and single oat cultivars as well as single maize and single barnyard grass cultivars/proveniences separated species-specific in cluster analyses. In the majority of cases the species separation was correct, but in a few cases, the spectra of the root tips had to be omitted to ensure the precise separation between the species. Therefore, species differentiation is possible regardless of the cultivar or provenience. Consequently, all tested cultivars of pea and oat spectra were analyzed together and separated within a cluster analysis according to their affiliated species. The same result was found in a cluster analysis with maize and barnyard grass spectra. Secondly, a cluster analysis with all species (pea, oat, maize and barnyard grass was performed. The species split up species-specific and formed a dicotyledonous pea cluster and a monocotyledonous cluster subdivided in oat, maize and barnyard grass subclusters. Thirdly, cultivar or provenience differentiations within one species were possible in one of the two replicated experiments. But these separations were less resilient.

  6. Grass-Shrub Associations over a Precipitation Gradient and Their Implications for Restoration in the Great Basin, USA.

    Directory of Open Access Journals (Sweden)

    Maike F Holthuijzen

    Full Text Available As environmental stress increases positive (facilitative plant interactions often predominate. Plant-plant associations (or lack thereof can indicate whether certain plant species favor particular types of microsites (e.g., shrub canopies or plant-free interspaces and can provide valuable insights into whether "nurse plants" will contribute to seeding or planting success during ecological restoration. It can be difficult, however, to anticipate how relationships between nurse plants and plants used for restoration may change over large-ranging, regional stress gradients. We investigated associations between the shrub, Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis, and three common native grasses (Poa secunda, Elymus elymoides, and Pseudoroegneria spicata, representing short-, medium-, and deep-rooted growth forms, respectively, across an annual rainfall gradient (220-350 mm in the Great Basin, USA. We hypothesized that positive shrub-grass relationships would become more frequent at lower rainfall levels, as indicated by greater cover of grasses in shrub canopies than vegetation-free interspaces. We sampled aerial cover, density, height, basal width, grazing status, and reproductive status of perennial grasses in canopies and interspaces of 25-33 sagebrush individuals at 32 sites along a rainfall gradient. We found that aerial cover of the shallow rooted grass, P. secunda, was higher in sagebrush canopy than interspace microsites at lower levels of rainfall. Cover and density of the medium-rooted grass, E. elymoides were higher in sagebrush canopies than interspaces at all but the highest rainfall levels. Neither annual rainfall nor sagebrush canopy microsite significantly affected P. spicata cover. E. elymoides and P. spicata plants were taller, narrower, and less likely to be grazed in shrub canopy microsites than interspaces. Our results suggest that exploring sagebrush canopy microsites for restoration of native perennial

  7. Low Light Availability Alters Root Exudation and Reduces Putative Beneficial Microorganisms in Seagrass Roots

    Directory of Open Access Journals (Sweden)

    Belinda C. Martin

    2018-01-01

    Full Text Available Seagrass roots host a diverse microbiome that is critical for plant growth and health. Composition of microbial communities can be regulated in part by root exudates, but the specifics of these interactions in seagrass rhizospheres are still largely unknown. As light availability controls primary productivity, reduced light may impact root exudation and consequently the composition of the root microbiome. Hence, we analyzed the influence of light availability on root exudation and community structure of the root microbiome of three co-occurring seagrass species, Halophila ovalis, Halodule uninervis and Cymodocea serrulata. Plants were grown under four light treatments in mesocosms for 2 weeks; control (100% surface irradiance (SI, medium (40% SI, low (20% SI and fluctuating light (10 days 20% and 4 days 100%. 16S rDNA amplicon sequencing revealed that microbial diversity, composition and predicted function were strongly influenced by the presence of seagrass roots, such that root microbiomes were unique to each seagrass species. Reduced light availability altered seagrass root exudation, as characterized using fluorescence spectroscopy, and altered the composition of seagrass root microbiomes with a reduction in abundance of potentially beneficial microorganisms. Overall, this study highlights the potential for above-ground light reduction to invoke a cascade of changes from alterations in root exudation to a reduction in putative beneficial microorganisms and, ultimately, confirms the importance of the seagrass root environment – a critical, but often overlooked space.

  8. Evapotranspiration in three plant communities of a Rhigozum ...

    African Journals Online (AJOL)

    Evapotranspiration losses in three Rhigozum trichotomum plant communities namely, pure grass, pure R. trichotomum and a mixed stand of grass and R. trichotomum were determined during the 1985-86 growing season. Three hydrologically isolated plots in each community type were irrigated and changes in soil water ...

  9. Root dynamics in an artificially constructed regenerating longleaf pine ecosystem are affected by atmospheric CO(2) enrichment.

    Science.gov (United States)

    Pritchard, S G.; Davis, M A.; Mitchell, R J.; Prior, S A.; Boykin, D L.; Rogers, H H.; Runion, G B.

    2001-08-01

    Differential responses to elevated atmospheric CO(2) concentration exhibited by different plant functional types may alter competition for above- and belowground resources in a higher CO(2) world. Because C allocation to roots is often favored over C allocation to shoots in plants grown with CO(2) enrichment, belowground function of forest ecosystems may change significantly. We established an outdoor facility to examine the effects of elevated CO(2) on root dynamics in artificially constructed communities of five early successional forest species: (1) a C(3) evergreen conifer (longleaf pine, Pinus palustris Mill.); (2) a C(4) monocotyledonous bunch grass (wiregrass, Aristida stricta Michx.); (3) a C(3) broadleaf tree (sand post oak, Quercus margaretta); (4) a C(3) perennial herbaceous legume (rattlebox, Crotalaria rotundifolia Walt. ex Gemel); and (5) an herbaceous C(3) dicotyledonous perennial (butterfly weed, Asclepias tuberosa L.). These species are common associates in early successional longleaf pine savannahs throughout the southeastern USA and represent species that differ in life-form, growth habit, physiology, and symbiotic relationships. A combination of minirhizotrons and soil coring was used to examine temporal and spatial rooting dynamics from October 1998 to October 1999. CO(2)-enriched plots exhibited 35% higher standing root crop length, 37% greater root length production per day, and 47% greater root length mortality per day. These variables, however, were enhanced by CO(2) enrichment only at the 10-30 cm depth. Relative root turnover (flux/standing crop) was unchanged by elevated CO(2). Sixteen months after planting, root biomass of pine was 62% higher in elevated compared to ambient CO(2) plots. Conversely, the combined biomass of rattlebox, wiregrass, and butterfly weed was 28% greater in ambient compared to high CO(2) plots. There was no difference in root biomass of oaks after 16 months of exposure to elevated CO(2). Using root and shoot

  10. Variation in important pasture grasses: I. Morphological and ...

    African Journals Online (AJOL)

    Variation in important pasture grasses: I. Morphological and geographical variation. ... Seven species are important pasture grasses throughout the western Transvaal, Orange Free State, northern Cape and Natal. ... Language: English.

  11. Assessment of some macromineral concentration of a grass/ legume ...

    African Journals Online (AJOL)

    Assessment of some macromineral concentration of a grass/ legume sward in ... Bulletin of Animal Health and Production in Africa ... The study aimed to determine the concentration of some macromineral elements in the grass/legume pasture ...

  12. Modelling of excess noise attnuation by grass and forest | Onuu ...

    African Journals Online (AJOL)

    , guinea grass (panicum maximum) and forest which comprises iroko (milicia ezcelea) and white afara (terminalia superba) trees in the ratio of 2:1 approximately. Excess noise attenuation spectra have been plotted for the grass and forest for ...

  13. Relationship between the Al resistance of grasses and their adaptation to an infertile habitat.

    Science.gov (United States)

    Poozesh, Vahid; Cruz, Pablo; Choler, Philippe; Bertoni, Georges

    2007-05-01

    Original data on Al resistance, relative growth rate and leaf traits of five European grasses as well as literature data on Al resistance, habitat preference and traits of grasses were considered to determine whether (a) Al resistance is correlated to a growth conservative strategy and (b) species occurrence could be useful to assess Al toxicity in meadows on acid soils. The Al resistance of 15 species was represented by the Al activity in nutrient solution that resulted in a 50 % decrease in root length, [Al(3+)](50), or, for published values, in root or plant biomass. The correlations between Al resistance and acidity or nitrogen indices and the correlation between Al resistance and selected traits (relative growth rate, leaf dry matter content, specific leaf area and leaf thickness) were calculated. Principal component analysis was used for the characterization of the relationships between Al resistance and measured traits. The [Al(3+)](50) values of the resistant species Molinia caerulea and Sieglingia decumbens were 13 and 26 microm [Al(3+)](50), respectively. The known Al resistance of 15 species that were mainly of the intermediate strategy competitor-stress tolerator-ruderal (C-S-R) type and of the S type was correlated with Ellenberg's nitrogen and acidity indices. For the whole set of species, the correlation between Al resistance and traits was not significant. The Al resistance of the C-S-R species was variable and independent of their traits. S-type species, adapted to acid soils and with traits of conservative strategy, displayed Al resistance. The large difference in Al resistance between grasses may help assess Al soil toxicity by using the abundance of grasses.

  14. The Evaluation of Alkali Grass (Puccinellia ciliata Bor Populations in Aydin Province of Turkey

    Directory of Open Access Journals (Sweden)

    İlkay Yavaş

    2017-08-01

    Full Text Available Alkali grass grows in waterlogged, saline and alaline soils. The main problem in these soils is minerals at toxic level. The toxic ions are chloride, sodium and boron. A number of techniques have been investigated for removing toxic metals from the soil. Today, the cost-effective and environmentally technique is phytoremediation, using hyperaccumulator plants. Alkali grass (Puccinellia ciliata Bor is suggested as a hyperaccumulator plant by the combination of more favourable characteristics with salt and waterlogging tolerance, high biomass value and convincing nutritive value for adverse environmental conditions. For this reason, we collected alkali grass and soil samples from five different locations in Aydın-Muğla highway, Turanlar and Sınırteke villages in Germencik-Aydın. In the soil analysis, we observed that K accumulation varies between root, shoot and panicle at least whereas Na and B shows more variation on whole plant portions among locations. Intense aerenchyma development on the root tips of Puccinellia plant was observed and it is determined as radial lysogenic aerenchyma formation. Average plant height and dry matter values were between 47.2-74.4 cm and 15.61-80.85 g/plant according to locations. The highest plant height value was obtained from the first location whereas the highest dry matter yield was detected in the fifth location. In conclusion, plants from fifth location can be regarded as fodder plants in these areas. Our results indicated that alkali grass can be effective for phytoextraction of sodium and boron from contaminated sites.

  15. Seedling root targets

    Science.gov (United States)

    Diane L. Haase

    2011-01-01

    Roots are critical to seedling performance after outplanting. Although root quality is not as quick and simple to measure as shoot quality, target root characteristics should be included in any seedling quality assessment program. This paper provides a brief review of root characteristics most commonly targeted for operational seedling production. These are: root mass...

  16. Production of N2O in grass-clover pastures

    International Nuclear Information System (INIS)

    Carter, M.S.

    2005-09-01

    Agricultural soils are known to be a considerable source of the strong greenhouse gas nitrous oxide (N 2 O), and in soil N 2 O is mainly produced by nitrifying and denitrifying bacteria. In Denmark, grass-clover pastures are an important component of the cropping system in organic as well as conventional dairy farming, and on a European scale grass-clover mixtures represent a large part of the grazed grasslands. Biological dinitrogen (N 2 ) fixation in clover provides a major N input to these systems, but knowledge is sparse regarding the amount of fixed N 2 lost from the grasslands as N2O. Furthermore, urine patches deposited by grazing cattle are known to be hot-spots of N 2 O emission, but the mechanisms involved in the N 2 O production in urine-affected soil are very complex and not well understood. The aim of this Ph.D. project was to increase the knowledge of the biological and physical-chemical mechanisms, which control the production of N2O in grazed grass-clover pastures. Three experimental studies were conducted with the objectives of: 1: assessing the contribution of recently fixed N 2 as a source of N 2 O. 2: examining the link between N 2 O emission and carbon mineralization in urine patches. 3: investigating the effect of urine on the rates and N 2 O loss ratios of nitrification and denitrification, and evaluating the impact of the chemical conditions that arise in urine affected soil. The results revealed that only 3.2 ± 0.5 ppm of the recently fixed N 2 was emitted as N2O on a daily basis. Thus, recently fixed N released via easily degradable clover residues appears to be a minor source of N2O. Furthermore, increased N 2 O emission following urine application at rates up to 5.5 g N m -2 was not caused by enhanced denitrification stimulated by labile compounds released from scorched plant roots. Finally, the increase of soil pH and ammonium following urine application led to raised nitrification rate, which appeared to be the most important factor

  17. Synergy between root hydrotropic response and root biomass in maize (Zea mays L.) enhances drought avoidance.

    Science.gov (United States)

    Eapen, Delfeena; Martínez-Guadarrama, Jesús; Hernández-Bruno, Oralia; Flores, Leonardo; Nieto-Sotelo, Jorge; Cassab, Gladys I

    2017-12-01

    Roots of higher plants change their growth direction in response to moisture, avoiding drought and gaining maximum advantage for development. This response is termed hydrotropism. There have been few studies of root hydrotropism in grasses, particularly in maize. Our goal was to test whether an enhanced hydrotropic response of maize roots correlates with a better adaptation to drought and partial/lateral irrigation in field studies. We developed a laboratory bioassay for testing hydrotropic response in primary roots of 47 maize elite DTMA (Drought Tolerant Maize for Africa) hybrids. After phenotyping these hybrids in the laboratory, selected lines were tested in the field. Three robust and three weak hybrids were evaluated employing three irrigation procedures: normal irrigation, partial lateral irrigation and drought. Hybrids with a robust hydrotropic response showed growth and developmental patterns, under drought and partial lateral irrigation, that differed from weak hydrotropic responders. A correlation between root crown biomass and grain yield in hybrids with robust hydrotropic response was detected. Hybrids with robust hydrotropic response showed earlier female flowering whereas several root system traits, such as projected root area, median width, maximum width, skeleton width, skeleton nodes, average tip diameter, rooting depth skeleton, thinner aboveground crown roots, as well as stem diameter, were considerably higher than in weak hydrotropic responders in the three irrigation procedures utilized. These results demonstrate the benefit of intensive phenotyping of hydrotropism in primary roots since maize plants that display a robust hydrotropic response grew better under drought and partial lateral irrigation, indicating that a selection for robust hydrotropism might be a promising breeding strategy to improve drought avoidance in maize. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Notes on Alien Bromus Grasses in Taiwan

    Directory of Open Access Journals (Sweden)

    Ming-Jer Jung

    2006-06-01

    Full Text Available Bromus carinatus Hook. & Arn., Bromus hordeaceus L., Bromus pubescens Muhl. ex Willd. and Bromus secalinus L. were recently found at middle elevations of southern and central Taiwan, respectively. We present taxonomic treatments, distribution map, and line-drawings of these introduced alien brome grasses.

  19. Notes on the nomenclature of some grasses

    NARCIS (Netherlands)

    Henrard, J.Th.

    1941-01-01

    In a former article 1) many new combinations and critical observations were published on various grasses all over the world. New investigations in critical genera together with the study of the existing literature made it necessary to accept various other arrangements in this important family. The

  20. Grass Pollen Pollution from Biofuels Farming

    Czech Academy of Sciences Publication Activity Database

    Ratajová, A.; Tříska, Jan; Vrchotová, Naděžda; Kolář, L.; Kužel, S.

    2013-01-01

    Roč. 26, č. 4 (2013), s. 199-203 ISSN 2151-321X R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : grass pollen pollution * biofuels farming * temperate climate * PK-fertilization * N-fertilization * phenolic Subject RIV: EH - Ecology, Behaviour Impact factor: 0.556, year: 2013

  1. Germination of Themeda triandra (Kangaroo grass) as affected by ...

    African Journals Online (AJOL)

    Low rainfall in range areas restricts germination, growth and development of majority of range grasses. However, germination and establishment potential of forage grasses vary and depends on environmental conditions. Themeda triandra is an excellent known grass to grow under different environmental conditions.

  2. Convex relationships in ecosystems containing mixtures of trees and grass

    CSIR Research Space (South Africa)

    Scholes, RJ

    2003-12-01

    Full Text Available The relationship between grass production and the quantity of trees in mixed tree-grass ecosystems (savannas) is convex for all or most of its range. In other words, the grass production declines more steeply per unit increase in tree quantity...

  3. Names of Southern African grasses: Name changes and additional ...

    African Journals Online (AJOL)

    The main reasons for changes in botanical names are briefly reviewed, with examples from the lists. At this time, about 1040 grass species and subspecific taxa are recognized in the subcontinent. Keywords: botanical research; botanical research institute; botany; grass; grasses; identification; name change; nomenclature; ...

  4. Diet Switching by Mammalian Herbivores in Response to Exotic Grass Invasion.

    Directory of Open Access Journals (Sweden)

    Carolina Bremm

    Full Text Available Invasion by exotic grasses is a severe threat to the integrity of grassland ecosystems all over the world. Because grasslands are typically grazed by livestock and wildlife, the invasion is a community process modulated by herbivory. We hypothesized that the invasion of native South American grasslands by Eragrostis plana Nees, an exotic tussock-forming grass from Africa, could be deterred by grazing if grazers switched dietary preferences and included the invasive grass as a large proportion of their diets. Bos taurus (heifers and Ovis aries (ewes grazed plots with varying degrees of invasion by E. plana in a replicated manipulative experiment. Animal positions and species grazed were observed every minute in 45-min grazing session. Proportion of bites and steps in and out of E. plana tussocks were measured and used to calculate several indices of selectivity. Both heifers and ewes exhibited increasing probability of grazing E. plana as the proportion of area covered by tussocks increased, but they behaved differently. In agreement with expectations based on the allometry of dietary preferences and morphology, ewes consumed a low proportion of E. plana, except in areas that had more than 90% E. plana cover. Heifers consumed proportionally more E. plana than ewes. Contrary to our hypothesis, herbivores did not exhibit dietary switching towards the invasive grass. Moreover, they exhibited avoidance of the invasive grass and preference for short-statured native species, both of which should tend to enhance invasion. Unless invasive plants are highly palatable to livestock, the effect of grazing to deter the invasion is limited, due to the inherent avoidance of the invasive grass by the main grazers in the ecosystem, particularly sheep.

  5. Non-linear partial least square regression increases the estimation accuracy of grass nitrogen and phosphorus using in situ hyperspectral and environmental data

    CSIR Research Space (South Africa)

    Ramoelo, Abel

    2013-06-01

    Full Text Available in situ hyperspectral and environmental variables yielded the highest grass N and P estimation accuracy (R2 = 0.81, root mean square error (RMSE) = 0.08, and R2 = 0.80, RMSE = 0.03, respectively) as compared to using remote sensing variables only...

  6. Plant responsiveness to root-root communication of stress cues.

    Science.gov (United States)

    Falik, Omer; Mordoch, Yonat; Ben-Natan, Daniel; Vanunu, Miriam; Goldstein, Oron; Novoplansky, Ariel

    2012-07-01

    Phenotypic plasticity is based on the organism's ability to perceive, integrate and respond to multiple signals and cues informative of environmental opportunities and perils. A growing body of evidence demonstrates that plants are able to adapt to imminent threats by perceiving cues emitted from their damaged neighbours. Here, the hypothesis was tested that unstressed plants are able to perceive and respond to stress cues emitted from their drought- and osmotically stressed neighbours and to induce stress responses in additional unstressed plants. Split-root Pisum sativum, Cynodon dactylon, Digitaria sanguinalis and Stenotaphrum secundatum plants were subjected to osmotic stress or drought while sharing one of their rooting volumes with an unstressed neighbour, which in turn shared its other rooting volume with additional unstressed neighbours. Following the kinetics of stomatal aperture allowed testing for stress responses in both the stressed plants and their unstressed neighbours. In both P. sativum plants and the three wild clonal grasses, infliction of osmotic stress or drought caused stomatal closure in both the stressed plants and in their unstressed neighbours. While both continuous osmotic stress and drought induced prolonged stomatal closure and limited acclimation in stressed plants, their unstressed neighbours habituated to the stress cues and opened their stomata 3-24 h after the beginning of stress induction. The results demonstrate a novel type of plant communication, by which plants might be able to increase their readiness to probable future osmotic and drought stresses. Further work is underway to decipher the identity and mode of operation of the involved communication vectors and to assess the potential ecological costs and benefits of emitting and perceiving drought and osmotic stress cues under various ecological scenarios.

  7. Estimating grass and grass silage degradation characteristics by in situ and in vitro gas production methods

    Directory of Open Access Journals (Sweden)

    Danijel Karolyi

    2010-01-01

    Full Text Available Fermentation characteristics of grass and grass silage at different maturities were studied using in situ and in vitro gas production methods. In situ data determined difference between grass and silage. Degradable fraction decreased as grass matured while the undegradable fraction increased. Rate of degradation (kd was slower for silage than fresh grass. Gas production method (GP data showed that fermentation of degradable fraction was different between stage of maturity in both grass and silage. Other data did not show any difference with the exception for the rate of GP of soluble and undegradable fraction. The in situ degradation characteristics were estimated from GP characteristics. The degradable and undegradable fractions could be estimated by multiple relationships. Using the three-phases model for gas production kd and fermentable organic matter could be estimated from the same parameters. The only in situ parameter that could not be estimated with GP parameters was the soluble fraction. The GP method and the three phases model provided to be an alternative to the in situ method for animal feed evaluations.

  8. Grass pollen immunotherapy induces highly cross-reactive IgG antibodies to group V allergen from different grass species

    NARCIS (Netherlands)

    van Ree, R.; Brewczyński, P. Z.; Tan, K. Y.; Mulder-Willems, H. J.; Widjaja, P.; Stapel, S. O.; Aalberse, R. C.; Kroon, A. M.

    1995-01-01

    Sera from two groups of patients receiving grass pollen immunotherapy were tested on IgG reactivity with group V allergen from six different grass species. One group of patients was treated with a mixture of 10 grass species, and the other with a mixture of five. Only Lolium perenne, Dactylis

  9. Analysis of phytochelatin complexes in the lead tolerant vetiver grass [Vetiveria zizanioides (L.)] using liquid chromatography and mass spectrometry

    International Nuclear Information System (INIS)

    Andra, Syam S.; Datta, Rupali; Sarkar, Dibyendu; Saminathan, Sumathi K.M.; Mullens, Conor P.; Bach, Stephan B.H.

    2009-01-01

    Ethylenediamene tetraacetic acid (EDTA) has been used to mobilize soil lead (Pb) and enhance plant uptake for phytoremediation. Chelant bound Pb is considered less toxic compared to free Pb ions and hence might induce less stress on plants. Characterization of possible Pb complexes with phytochelatins (PC n , metal-binding peptides) and EDTA in plant tissues will enhance our understanding of Pb tolerance mechanisms. In a previous study, we showed that vetiver grass (Vetiveria zizanioides L.) can accumulate up to 19,800 and 3350 mg Pb kg -1 dry weight in root and shoot tissues, respectively; in a hydroponics set-up. Following the basic incubation study, a greenhouse experiment was conducted to elucidate the efficiency of vetiver grass (with or without EDTA) in remediating Pb-contaminated soils from actual residential sites where Pb-based paints were used. The levels of total thiols, PC n , and catalase (an antioxidant enzyme) were measured in vetiver root and shoot following chelant-assisted phytostabilization. In the presence of 15 mM kg -1 EDTA, vetiver accumulated 4460 and 480 mg Pb kg -1 dry root and shoot tissue, respectively; that are 15- and 24-fold higher compared to those in untreated controls. Despite higher Pb concentrations in the plant tissues, the amount of total thiols and catalase activity in EDTA treated vetiver tissues was comparable to chelant unamended controls, indicating lowered Pb toxicity by chelation with EDTA. The identification of glutathione (referred as PC 1 ) (m/z 308.2), along with chelated complexes like Pb-EDTA (m/z 498.8) and PC 1 -Pb-EDTA (m/z 805.3) in vetiver root tissue using electrospray tandem mass spectrometry (ES-MS) highlights the possible role of such species towards Pb tolerance in vetiver grass. - Chelated lead in conjunction with phytochelatins synthesis and complexation reduces stress in the lead tolerant vetiver grass.

  10. Analysis of phytochelatin complexes in the lead tolerant vetiver grass [Vetiveria zizanioides (L.)] using liquid chromatography and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Andra, Syam S., E-mail: syam.andra@gmail.co [Environmental Geochemistry Laboratory, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX (United States); Datta, Rupali [Biological Sciences, Michigan Technological University, Houghton, MI (United States); Sarkar, Dibyendu [Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ (United States); Saminathan, Sumathi K.M. [Environmental Geochemistry Laboratory, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX (United States); Mullens, Conor P.; Bach, Stephan B.H. [Department of Chemistry, University of Texas at San Antonio, San Antonio, TX (United States)

    2009-07-15

    Ethylenediamene tetraacetic acid (EDTA) has been used to mobilize soil lead (Pb) and enhance plant uptake for phytoremediation. Chelant bound Pb is considered less toxic compared to free Pb ions and hence might induce less stress on plants. Characterization of possible Pb complexes with phytochelatins (PC{sub n}, metal-binding peptides) and EDTA in plant tissues will enhance our understanding of Pb tolerance mechanisms. In a previous study, we showed that vetiver grass (Vetiveria zizanioides L.) can accumulate up to 19,800 and 3350 mg Pb kg{sup -1} dry weight in root and shoot tissues, respectively; in a hydroponics set-up. Following the basic incubation study, a greenhouse experiment was conducted to elucidate the efficiency of vetiver grass (with or without EDTA) in remediating Pb-contaminated soils from actual residential sites where Pb-based paints were used. The levels of total thiols, PC{sub n}, and catalase (an antioxidant enzyme) were measured in vetiver root and shoot following chelant-assisted phytostabilization. In the presence of 15 mM kg {sup -1} EDTA, vetiver accumulated 4460 and 480 mg Pb kg{sup -1} dry root and shoot tissue, respectively; that are 15- and 24-fold higher compared to those in untreated controls. Despite higher Pb concentrations in the plant tissues, the amount of total thiols and catalase activity in EDTA treated vetiver tissues was comparable to chelant unamended controls, indicating lowered Pb toxicity by chelation with EDTA. The identification of glutathione (referred as PC{sub 1}) (m/z 308.2), along with chelated complexes like Pb-EDTA (m/z 498.8) and PC{sub 1}-Pb-EDTA (m/z 805.3) in vetiver root tissue using electrospray tandem mass spectrometry (ES-MS) highlights the possible role of such species towards Pb tolerance in vetiver grass. - Chelated lead in conjunction with phytochelatins synthesis and complexation reduces stress in the lead tolerant vetiver grass.

  11. Morphology, gas exchange, and chlorophyll content of longleaf pine seedlings in response to rooting volume, copper root pruning, and nitrogen supply in a container nursery

    Science.gov (United States)

    R. Kasten Dumroese; Shi-Jean Susana Sung; Jeremiah R. Pinto; Amy Ross-Davis; D. Andrew Scott

    2013-01-01

    Few pine species develop a seedling grass stage; this growth phase, characterized by strong, carrot-like taproots and a stem-less nature, poses unique challenges during nursery production. Fertilization levels beyond optimum could result in excessive diameter growth that reduces seedling quality as measured by the root bound index (RBI). We grew longleaf pine (Pinus...

  12. Root Characteristics of Perennial Warm-Season Grasslands Managed for Grazing and Biomass Production

    Directory of Open Access Journals (Sweden)

    Rattan Lal

    2013-07-01

    Full Text Available Minirhizotrons were used to study root growth characteristics in recently established fields dominated by perennial C4-grasses that were managed either for cattle grazing or biomass production for bioenergy in Virginia, USA. Measurements over a 13-month period showed that grazing resulted in smaller total root volumes and root diameters. Under biomass management, root volume was 40% higher (49 vs. 35 mm3 and diameters were 20% larger (0.29 vs. 0.24 mm compared to grazing. While total root length did not differ between grazed and biomass treatments, root distribution was shallower under grazed areas, with 50% of total root length in the top 7 cm of soil, compared to 41% in ungrazed exclosures. These changes (i.e., longer roots and greater root volume in the top 10 cm of soil under grazing but the reverse at 17–28 cm soil depths were likely caused by a shift in plant species composition as grazing reduced C4 grass biomass and allowed invasion of annual unsown species. The data suggest that management of perennial C4 grasslands for either grazing or biomass production can affect root growth in different ways and this, in turn, may have implications for the subsequent carbon sequestration potential of these grasslands.

  13. Root Shock Revisited: Perspectives of Early Head Start Mothers on Community and Policy Environments and Their Effects on Child Health, Development, and School Readiness

    Science.gov (United States)

    McAllister, Carol L.; Thomas, Tammy L.; Green, Beth L.

    2009-01-01

    Racial differences in school readiness are a form of health disparity. By examining, from the perspective of low-income minority families participating in an Early Head Start study, community and policy environments as they shape and inform lived experiences, we identified several types of social and economic dislocation that undermine the efforts of parents to ready their children for school. The multiple dislocations of community triggered by housing and welfare reform and “urban renewal” are sources of stress for parents and children and affect the health and development of young children. Our findings suggest that racial differences in school readiness result not from race but from poverty and structural racism in American society. PMID:19059871

  14. Lead-210 and polonium-210 in grass

    Energy Technology Data Exchange (ETDEWEB)

    Hill, C R

    1960-07-16

    It appears that an important contribution to the observed ..cap alpha..-activity of grass may be provided by a process of natural fall-out in which lead-210 resulting from decay of atmospheric radon, together with a fraction of the equilibrium amount of its descendant polonium-210 are deposited by rainfall directly on to foliage. Metabolic uptake of part of this activity by sheep is indicated by the presence in the kidney of polonium-210. 6 references, 1 figure, 2 tables.

  15. ROOT Reference Documentation

    CERN Document Server

    Fuakye, Eric Gyabeng

    2017-01-01

    A ROOT Reference Documentation has been implemented to generate all the lists of libraries needed for each ROOT class. Doxygen has no option to generate or add the lists of libraries for each ROOT class. Therefore shell scripting and a basic C++ program was employed to import the lists of libraries needed by each ROOT class.

  16. Microbial community diversity in agroforestry and grass vegetative filter strips

    Science.gov (United States)

    Vegetative filter strips (VFS) have long been promoted as a soil conservation practice that yields many additional environmental benefits. Most previous studies have focused primarily on the role of vegetation and/or soil physical properties in these ecosystem services. Few studies have investigated...

  17. Grass Plants Bind, Retain, Uptake, and Transport Infectious Prions

    Directory of Open Access Journals (Sweden)

    Sandra Pritzkow

    2015-05-01

    Full Text Available Prions are the protein-based infectious agents responsible for prion diseases. Environmental prion contamination has been implicated in disease transmission. Here, we analyzed the binding and retention of infectious prion protein (PrPSc to plants. Small quantities of PrPSc contained in diluted brain homogenate or in excretory materials (urine and feces can bind to wheat grass roots and leaves. Wild-type hamsters were efficiently infected by ingestion of prion-contaminated plants. The prion-plant interaction occurs with prions from diverse origins, including chronic wasting disease. Furthermore, leaves contaminated by spraying with a prion-containing preparation retained PrPSc for several weeks in the living plant. Finally, plants can uptake prions from contaminated soil and transport them to aerial parts of the plant (stem and leaves. These findings demonstrate that plants can efficiently bind infectious prions and act as carriers of infectivity, suggesting a possible role of environmental prion contamination in the horizontal transmission of the disease.

  18. Grass plants bind, retain, uptake, and transport infectious prions.

    Science.gov (United States)

    Pritzkow, Sandra; Morales, Rodrigo; Moda, Fabio; Khan, Uffaf; Telling, Glenn C; Hoover, Edward; Soto, Claudio

    2015-05-26

    Prions are the protein-based infectious agents responsible for prion diseases. Environmental prion contamination has been implicated in disease transmission. Here, we analyzed the binding and retention of infectious prion protein (PrP(Sc)) to plants. Small quantities of PrP(Sc) contained in diluted brain homogenate or in excretory materials (urine and feces) can bind to wheat grass roots and leaves. Wild-type hamsters were efficiently infected by ingestion of prion-contaminated plants. The prion-plant interaction occurs with prions from diverse origins, including chronic wasting disease. Furthermore, leaves contaminated by spraying with a prion-containing preparation retained PrP(Sc) for several weeks in the living plant. Finally, plants can uptake prions from contaminated soil and transport them to aerial parts of the plant (stem and leaves). These findings demonstrate that plants can efficiently bind infectious prions and act as carriers of infectivity, suggesting a possible role of environmental prion contamination in the horizontal transmission of the disease. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Arbuscular mycorrhizal association enhances drought tolerance potential of promising bioenergy grass (Saccharum arundinaceum retz.).

    Science.gov (United States)

    Mirshad, P P; Puthur, Jos T

    2016-07-01

    The influence of arbuscular mycorrhizal fungi (AMF) (Glomus spp.) on some physiological and biochemical characteristics of bioenergy grass Saccharum arundinaceum subjected to drought stress was studied. The symbiotic association of Glomus spp. was established with S. arundinaceum, a potential bioenergy grass as evident from the increase in percentage of root infection and distribution frequency of vesicles when compared with non-arbuscular mycorrhizal plants. AMF-treated plants exhibited an enhanced accumulation of osmolytes such as sugars and proline and also increased protein content under drought. AMF association significantly increased the accumulation of non-enzymatic antioxidants like phenols, ascorbate and glutathione as well as enhanced the activities of antioxidant enzymes such as SOD (superoxide dismutase), APX (ascorbate peroxidase) and GPX (guaiacol peroxidase) resulting in reduced lipid peroxidation in S. arundinaceum. AMF symbiosis also ameliorated the drought-induced reduction of total chlorophyll content and activities of photosystem I and II. The maximum quantum efficiency of PS II (F v/F m) and potential photochemical efficiency (F v/F o) were higher in AMF plants as compared to non-AMF plants under drought stress. These results indicate that AMF association alleviate drought stress in S. arundinaceum by the accumulation of osmolytes and non-enzymatic antioxidants and enhanced activities of antioxidant enzymes, and hence, the photosynthetic efficiency is improved resulting in increased biomass production. AMF association with energy grasses also improves the acclimatization of S. arundinaceum for growing in marginal lands of drought-affected soils.

  20. Conjoined lumbosacral nerve roots

    International Nuclear Information System (INIS)

    Kyoshima, Kazumitsu; Nishiura, Iwao; Koyama, Tsunemaro

    1986-01-01

    Several kinds of the lumbosacral nerve root anomalies have already been recognized, and the conjoined nerve roots is the most common among them. It does not make symptoms by itself, but if there is a causation of neural entrapment, for example, disc herniation, lateral recessus stenosis, spondylolisthesis, etc., so called ''biradicular syndrome'' should occur. Anomalies of the lumbosacral nerve roots, if not properly recognized, may lead to injury of these nerves during operation of the lumbar spine. Recently, the chance of finding these anomalous roots has been increased more and more with the use of metrizamide myelography and metrizamide CT, because of the improvement of the opacification of nerve roots. We describe the findings of the anomalous roots as revealed by these two methods. They demonstrate two nerve roots running parallel and the asymmetrical wide root sleeve. Under such circumstances, it is important to distinguish the anomalous roots from the normal ventral and dorsal roots. (author)

  1. Root canal irrigants

    OpenAIRE

    Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

    2010-01-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are...

  2. Diazotroph-Bacterial Community Structure of Root Nodules Account for Two-Fold Differences in Plant Growth: Consequences for Global Biogeochemical Cycles

    Science.gov (United States)

    Williams, M. A.

    2016-12-01

    The bacterial communities that inhabit and function as mutualists in the nodules of soybean, a major worldwide crop, are a fundamental determinant of plant growth and global nitrogen and carbon cycles. Unfertilized soybean can derive up to 90% of its nitrogen through bacterial-driven diazotrophy. It was the goal of the research in this study to assess whether different bacterial taxa (e.g. Bradyrhizobia spp.) differ in their soybean growth supportive role, which could then feedback to alter global biogeochemical cycling. Using 16S rRNA and NifH genes, nodule bacterial communities were shown to vary across 9 different cultivars of soybean, and that the variation between cultivars were highly correlated to plant yield (97 to 188 bu/Ha) and nitrogen. The relative abundances of gene sequences associated with the closest taxonomic match (NCBI), indicated that several taxa were (r= 0.76) negatively (e.g. Bradyrhizobium sp Ec3.3) or (r= 0.84) positively (e.g. Bradyrhizobium elkanii WSM 2783) correlated with plant yield. Other non-Rhizobiaceae taxa, such as Rhodopseudomonas spp. were also prevalent and correlated with plant yield. Soybeans and other leguminous crops will become increasingly important part of world food production, soil fertility and global biogeochemical cycles with rising population and food demand. The study demonstrates the importance of plant-microbial feedbacks driving plant growth but also ramifications for global cycling of nitrogen and carbon.

  3. PROCESSING UAV AND LIDAR POINT CLOUDS IN GRASS GIS

    Directory of Open Access Journals (Sweden)

    V. Petras

    2016-06-01

    Full Text Available Today’s methods of acquiring Earth surface data, namely lidar and unmanned aerial vehicle (UAV imagery, non-selectively collect or generate large amounts of points. Point clouds from different sources vary in their properties such as number of returns, density, or quality. We present a set of tools with applications for different types of points clouds obtained by a lidar scanner, structure from motion technique (SfM, and a low-cost 3D scanner. To take advantage of the vertical structure of multiple return lidar point clouds, we demonstrate tools to process them using 3D raster techniques which allow, for example, the development of custom vegetation classification methods. Dense point clouds obtained from UAV imagery, often containing redundant points, can be decimated using various techniques before further processing. We implemented and compared several decimation techniques in regard to their performance and the final digital surface model (DSM. Finally, we will describe the processing of a point cloud from a low-cost 3D scanner, namely Microsoft Kinect, and its application for interaction with physical models. All the presented tools are open source and integrated in GRASS GIS, a multi-purpose open source GIS with remote sensing capabilities. The tools integrate with other open source projects, specifically Point Data Abstraction Library (PDAL, Point Cloud Library (PCL, and OpenKinect libfreenect2 library to benefit from the open source point cloud ecosystem. The implementation in GRASS GIS ensures long term maintenance and reproducibility by the scientific community but also by the original authors themselves.

  4. Potential of vetiver (vetiveria zizanioides l.) grass in removing selected pahs from diesel contaminated soil

    International Nuclear Information System (INIS)

    Nisa, W.U.; Rashid, A.

    2015-01-01

    Phytoremediation has been renowned as an encouraging technology for the remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soils, little is known about how plant species behave during the process of PAH phytoremediation. Therefore, the aim of this study was to investigate the effectiveness of vetiver (Vetiveria zizanioides L.) plant in PAH phytoremediation and extraction potential of Vetiveria zizanioides for selected PAHs from the diesel contaminated soil. The field soil samples were spiked with varying concentrations (0.5% and 1%) of diesel and used for pot experiment which was conducted in greenhouse. Vetiver grass was used as experimental plant. Physico-chemical analysis of soil was performed before and after the experiment. Concentration of selected PAHs i.e. phenanthrene, pyrene and benzo(a)pyrene in soil was determined using HPLC. Plant parameters such as root/shoot length and dry mass were compared after harvest. Concentrations of PAHs were also determined in plant material and in soils after harvesting. Result showed that initial concentration of phenanthrene was significantly different from final concentration in treatments in which soil was spiked with diesel. Initial and final concentration of pyrene in soil was also significantly different from each other in two treatments in which soil was spiked with 1% diesel. Pyrene concentration was significantly different in roots and shoots of plants while benzo(a)pyrene concentration in treatments in which soil was spiked with diesel was also significantly different from roots and shoots. Phenanthrene was less extracted by the plant in all the treatments and it was present in higher concentration in soil as compared to plant. Our results indicate that vetiver grass has effectively removed PAHs from soil consequently a significantly higher root and shoot uptake of PAHs was observed than control treatments. Study concludes Vetiveria zizanioides as potentially promising plant specie for the removal

  5. Interactive effects of plant-available soil silicon and herbivory on competition between two grass species

    Science.gov (United States)

    Garbuzov, Mihail; Reidinger, Stefan; Hartley, Susan E.

    2011-01-01

    Background and Aims The herbivore defence system of true grasses (Poaceae) is predominantly based on silicon that is taken up from the soil and deposited in the leaves in the form of abrasive phytoliths. Silicon uptake mechanisms can be both passive and active, with the latter suggesting that there is an energetic cost to silicon uptake. This study assessed the effects of plant-available soil silicon and herbivory on the competitive interactions between the grasses Poa annua, a species that has previously been reported to accumulate only small amounts of silicon, and Lolium perenne, a high silicon accumulator. Methods Plants were grown in mono- and mixed cultures under greenhouse conditions. Plant-available soil silicon levels were manipulated by adding silicon to the soil in the form of sodium silicate. Subsets of mixed culture pots were exposed to above-ground herbivory by desert locusts (Schistocerca gregaria). Key Results In the absence of herbivory, silicon addition increased biomass of P. annua but decreased biomass of L. perenne. Silicon addition increased foliar silicon concentrations of both grass species >4-fold. Under low soil-silicon availability the herbivores removed more leaf biomass from L. perenne than from P. annua, whereas under high silicon availability the reverse was true. Consequently, herbivory shifted the competitive balance between the two grass species, with the outcome depending on the availability of soil silicon. Conclusions It is concluded that a complex interplay between herbivore abundance, growth–defence trade-offs and the availability of soil silicon in the grasses' local environment affects the outcome of inter-specific competition, and so has the potential to impact on plant community structure. PMID:21868406

  6. The importance of cross-reactivity in grass pollen allergy

    Directory of Open Access Journals (Sweden)

    Aleksić Ivana

    2014-01-01

    Full Text Available According to the data obtained from in vivo and in vitro testing in Serbia, a significant number of patients have allergic symptoms caused by grass pollen. We examined the protein composition of grass pollens (Dactylis glomerata, Lolium perenne and Phleum pratense and cross-reactivity in patients allergic to grass pollen from our region. The grass pollen allergen extract was characterized by SDS-PAGE, while cross-reactivity of single grass pollens was revealed by immunoblot analysis. A high degree of cross-reactivity was demonstrated for all three single pollens in the sera of allergic patients compared to the grass pollen extract mixture. Confirmation of the existence of cross-reactivity between different antigenic sources facilitates the use of monovalent vaccines, which are easier to standardize and at the same time prevent further sensitization of patients and reduces adverse reactions. [Projekat Ministarstva nauke Republike Srbije, br. 172049 i br. 172024

  7. Evaluating grasses as a long-term energy resource

    Energy Technology Data Exchange (ETDEWEB)

    Christian, D.G.; Riche, A.B.

    2001-07-01

    The work reported here is part of an ongoing project that aims to evaluate the yields of three perennial rhizomatous grasses and determine their suitability as bio-energy crops. The work began in 1993, and the grasses have been monitored continuously since that time. This report covers the period 1999/2000, and includes: the performance of plots of the energy grasses Miscanthus grass, switchgrass and reed canary grass seven years after they were planted; assessment of the yield of 15 genotypes of Miscanthus planted in 1997; monitoring all the species throughout the growing period for the presence of pests, weeds and diseases; measurement of the amount of nitrate leached from below Miscanthus grass; investigating the occurrence of lodging in switchgrass. (Author)

  8. Determining the regional potential for a grass biomethane industry

    International Nuclear Information System (INIS)

    Smyth, Beatrice M.; Smyth, Henry; Murphy, Jerry D.

    2011-01-01

    Research highlights: → We identified assessment criteria for determining the regional potential for grass biomethane. → Grass biomethane is distributed via the natural gas grid. → The criteria include: land use; grass yields; gas grid coverage; availability of co-substrates. → The county with the highest potential can fuel 50% of cars or supply 130% of domestic gas consumption. - Abstract: Grass biogas/biomethane has been put forward as a renewable energy solution and it has been shown to perform well in terms of energy balance, greenhouse gas emissions and policy constraints. Biofuel and energy crop solutions are country-specific and grass biomethane has strong potential in countries with temperate climates and a high proportion of grassland, such as Ireland. For a grass biomethane industry to develop in a country, suitable regions (i.e. those with the highest potential) must be identified. In this paper, factors specifically related to the assessment of the potential of a grass biogas/biomethane industry are identified and analysed. The potential for grass biogas and grass biomethane is determined on a county-by-county basis using multi-criteria decision analysis. Values are assigned to each county and ratings and weightings applied to determine the overall county potential. The potential for grass biomethane with co-digestion of slaughter waste (belly grass) is also determined. The county with the highest potential (Limerick) is analysed in detail and is shown to have ready potential for production of gaseous biofuel to meet either 50% of the vehicle fleet or 130% of the domestic natural gas demand, through 25 facilities at a scale of ca. 30 kt yr -1 of feedstock. The assessment factors developed in this paper can be used in other resource studies into grass biomethane or other energy crops.

  9. Investigation of Desso GrassMaster® as application in hydraulic engineering

    NARCIS (Netherlands)

    Steeg, van der P.; Paulissen, M.P.C.P.; Roex, E.; Mommer, L.

    2015-01-01

    Dessa GrassMaster® is a reinforced grass system which is applied successfully on sports fields and enables to use a sports field more intensively than a normal grass field. In this report the possibility of an application of Dessa GrassMaster®in hydraulic conditions, with a focus on grass dikes, is

  10. The linear accumulation of atmospheric mercury by vegetable and grass leaves: Potential biomonitors for atmospheric mercury pollution.

    Science.gov (United States)

    Niu, Zhenchuan; Zhang, Xiaoshan; Wang, Sen; Ci, Zhijia; Kong, Xiangrui; Wang, Zhangwei

    2013-09-01

    One question in the use of plants as biomonitors for atmospheric mercury (Hg) is to confirm the linear relationships of Hg concentrations between air and leaves. To explore the origin of Hg in the vegetable and grass leaves, open top chambers (OTCs) experiment was conducted to study the relationships of Hg concentrations between air and leaves of lettuce (Lactuca sativa L.), radish (Raphanus sativus L.), alfalfa (Medicago sativa L.) and ryegrass (Lolium perenne L.). The influence of Hg in soil on Hg accumulation in leaves was studied simultaneously by soil Hg-enriched experiment. Hg concentrations in grass and vegetable leaves and roots were measured in both experiments. Results from OTCs experiment showed that Hg concentrations in leaves of the four species were significantly positively correlated with those in air during the growth time (p  0.05). Thus, Hg in grass leaves is mainly originated from the atmosphere, and grass leaves are more suitable as potential biomonitors for atmospheric Hg pollution. The effect detection limits (EDLs) for the leaves of alfalfa and ryegrass were 15.1 and 22.2 ng g(-1), respectively, and the biological detection limit (BDL) for alfalfa and ryegrass was 3.4 ng m(-3).

  11. Bacterial rhizosphere and endosphere populations associated with grasses and trees to be used for phytoremediation of crude oil contaminated soil.

    Science.gov (United States)

    Fatima, Kaneez; Afzal, Muhammad; Imran, Asma; Khan, Qaiser M

    2015-03-01

    Different grasses and trees were tested for their growth in a crude oil contaminated soil. Three grasses, Lolium perenne, Leptochloa fusca, Brachiaria mutica, and two trees, Lecucaena leucocephala and Acacia ampliceps, were selected to investigate the diversity of hydrocarbon-degrading rhizospheric and endophytic bacteria. We found a higher number of hydrocarbon degrading bacteria associated with grasses than trees and that the endophytic bacteria were taxonomically different from rhizosphere associated bacteria showing their spatial distribution with reference to plant compartment as well as genotype. The rhizospheric soil yielded 22 (59.45 %), root interior yielded 9 (24.32 %) and shoot interior yielded 6 (16.21 %) hydrocarbon-degrading bacteria. These bacteria possessed genes encoding alkane hydroxylase and showed multiple plant growth-promoting activities. Bacillus (48.64 %) and Acinetobacter (18.91 %) were dominant genera found in this study. At 2 % crude oil concentration, all bacterial isolates exhibited 25 %-78 % oil degradation and Acinetobacter sp. strain BRSI56 degraded maximum. Our study suggests that for practical application, support of potential bacteria combined with the grasses is more effective approach than trees to remediate oil contaminated soils.

  12. Intensidade de colonização do córtex radicular e sua relação com a absorção de fósforo pelo capim-pensacola Intensity of root cortex colonization and its relation with phosphorus uptake by pensacola grass

    Directory of Open Access Journals (Sweden)

    Danilo dos Santos Rheinheimer

    1995-01-01

    Full Text Available Em plantas micorrizadas, após a colonização do córtex radicular, as hifas fúngicas extendem-se no solo absorvendo uma maior quantidade de nutrientes, especialmente o fósforo. Este trabalho tem por objetivo avaliar a relação entre porcentagem e intensidade de colonização do córtex radicular com a absorção de fósforo. Usou-se os resultados de três experimentos desenvolvidos no Departamento de Solos da Universidade Federal de Santa Maria, no período de 1989 a 1992. No primeiro, usou-se cinco níveis de calagem representados por valores de pH (4,6; 5,0; 5,5; 6, 1 e 6,6 e duas doses de P2O5 (0 e 20mg/kg; no segundo, os mesmos valores de pH e quatro doses de P2O5 (0, 20, 50 e 70mg/kg e no terceiro, dois valores de pH (4,6 e 6,1 e três doses de P2O5, (50, 150 e 250mg/kg. Em todos os experimentos usaram-se três níveis de micorrização (solo fumigado, solo fumigado + esporos de fungos micorrízicos arbusculares (fMA nativos e solo natural e pensacola como planta hospedeira. Avaliou-se o fósforo absorvido pela parte aérea, a porcentagem e intensidade de colonização. Na avaliação da intensidade levou-se em consideração a presença de hifas internas e arbúsculos, atribuindo-se notas de 1 a 5. O córtex apresentou-se densamente colonizado pelas estruturas fúngicas em condições de solo ácido e com baixa disponibilidade de fósforo, coincidindo com as maiores absorções de fósforo. Em todos os experimentos e tratamentos a intensidade mostrou-se ser um parâmetro confiável na predição de absorção de fósforo pela pensacola.Plants colonized by mycorrhizal fungi are able to uptake more nutrients, especially phosphorus, than those without colonization due to the increase in the uptake área. The objective of this study was to evaluate the rate and the intensity of mycorrhizal colonization in Paspalum notatum roots and their correlation with P uptake. The data were obtained from three different experiment carried out in a

  13. Early inflorescence development in the grasses (Poaceae

    Directory of Open Access Journals (Sweden)

    Elizabeth A. Kellogg

    2013-07-01

    Full Text Available The shoot apical meristem of grasses produces the primary branches of the inflorescence, controlling inflorescence architecture and hence seed production. Whereas leaves are produced in a distichous pattern, with the primordia separated from each other by an angle of 180o, inflorescence branches are produced in a spiral in most species. The morphology and developmental genetics of the shift in phyllotaxis have been studied extensively in maize and rice. However, in wheat, Brachypodium, and oats, all in the grass subfamily Pooideae, the change in phyllotaxis does not occur; primary inflorescence branches are produced distichously. It is unknown whether the distichous inflorescence originated at the base of Pooideae, or whether it appeared several times independently. In this study, we show that Brachyelytrum, the genus sister to all other Pooideae has spiral phyllotaxis in the inflorescence, but that in the remaining 3000+ species of Pooideae, the phyllotaxis is two-ranked. These two-ranked inflorescences are not perfectly symmetrical, and have a clear front and back; this developmental axis has never been described in the literature and it is unclear what establishes its polarity. Strictly distichous inflorescences appear somewhat later in the evolution of the subfamily. Two-ranked inflorescences also appear in a few grass outgroups and sporadically elsewhere in the family, but unlike in Pooideae do not generally correlate with a major radiation of species. After production of branches, the inflorescence meristem may be converted to a spikelet meristem or may simply abort; this developmental decision appears to be independent of the branching pattern.

  14. ANATOMIC STRUCTURE OF CAMPANULA ROTUNDIFOLIA L. GRASS

    Directory of Open Access Journals (Sweden)

    V. N. Bubenchikova

    2017-01-01

    Full Text Available The article present results of the study for a anatomic structure of Campanula rotundifolia grass from Campanulaceae family. Despite its dispersion and application in folk medicine, there are no data about its anatomic structure, therefore to estimate the indices of authenticity and quality of raw materials it is necessary to develop microdiagnostical features in the first place, which could help introducing of thisplant in a medical practice. The purpose of this work is to study anatomical structureof Campanula rotundifolia grass to determine its diagnostic features. Methods. Thestudy for anatomic structure was carried out in accordance with the requirements of State Pharmacopoeia, edition XIII. Micromed laboratory microscope with digital adjutage was used to create microphotoes, Photoshop CC was used for their processing. Result. We have established that stalk epidermis is prosenchymal, slightly winding with straight of splayed end cells. After study for the epidermis cells we established that upper epidermis cells had straight walls and are slightly winding. The cells of lower epidermishave more winding walls with prolong wrinkled cuticule. Presence of simple one-cell, thin wall, rough papillose hair on leaf and stalk epidermis. Cells of epidermis in fauces of corolla are prosenchymal, with winding walls, straight or winding walls in a cup. Papillary excrescences can be found along the cup edges. Stomatal apparatus is anomocytic. Conclusion. As the result of the study we have carried out the research for Campanula rotundifolia grass anatomic structure, and determined microdiagnostic features for determination of raw materials authenticity, which included presence of simple, one-cell, thin-walled, rough papillose hair on both epidermises of a leaf, along the veins, leaf edge, and stalk epidermis, as well as the presence of epidermis cells with papillary excrescences along the edges of leaves and cups. Intercellular canals are situatedalong the

  15. Upgrated fuel from reed canary grass

    Energy Technology Data Exchange (ETDEWEB)

    Oravainen, H. [VTT Energy, Jyvaeskylae (Finland)

    1997-12-01

    Results described in this presentation are from a large EU-project - Development of a new crop production system based on delayed harvesting and system for its combined processing to chemical pulp and biofuel powder. This is a project to develop the use of Reed Canary Grass (Phalaris Arundinaceae) both for pulp industry and energy production. The main contractor of the project is Swedish University of Agricultural Sciences (coordinator), task coordinators are United Milling Systems A/S from Denmark, and Jaakko Poeyry Oy and VTT Energy from Finland In addition, there are partners from several countries participating in the project

  16. Prospects for Hybrid Breeding in Bioenergy Grasses

    DEFF Research Database (Denmark)

    Aguirre, Andrea Arias; Studer, Bruno; Frei, Ursula

    2012-01-01

    , we address crucial topics to implement hybrid breeding, such as the availability and development of heterotic groups, as well as biological mechanisms for hybridization control such as self-incompatibility (SI) and male sterility (MS). Finally, we present potential hybrid breeding schemes based on SI...... of different hybrid breeding schemes to optimally exploit heterosis for biomass yield in perennial ryegrass (Lolium perenne L.) and switchgrass (Panicum virgatum), two perennial model grass species for bioenergy production. Starting with a careful evaluation of current population and synthetic breeding methods...

  17. Ecology of root colonizing Massilia (Oxalobacteraceae.

    Directory of Open Access Journals (Sweden)

    Maya Ofek

    Full Text Available BACKGROUND: Ecologically meaningful classification of bacterial populations is essential for understanding the structure and function of bacterial communities. As in soils, the ecological strategy of the majority of root-colonizing bacteria is mostly unknown. Among those are Massilia (Oxalobacteraceae, a major group of rhizosphere and root colonizing bacteria of many plant species. METHODOLOGY/PRINCIPAL FINDINGS: The ecology of Massilia was explored in cucumber root and seed, and compared to that of Agrobacterium population, using culture-independent tools, including DNA-based pyrosequencing, fluorescence in situ hybridization and quantitative real-time PCR. Seed- and root-colonizing Massilia were primarily affiliated with other members of the genus described in soil and rhizosphere. Massilia colonized and proliferated on the seed coat, radicle, roots, and also on hyphae of phytopathogenic Pythium aphanidermatum infecting seeds. High variation in Massilia abundance was found in relation to plant developmental stage, along with sensitivity to plant growth medium modification (amendment with organic matter and potential competitors. Massilia absolute abundance and relative abundance (dominance were positively related, and peaked (up to 85% at early stages of succession of the root microbiome. In comparison, variation in abundance of Agrobacterium was moderate and their dominance increased at later stages of succession. CONCLUSIONS: In accordance with contemporary models for microbial ecology classification, copiotrophic and competition-sensitive root colonization by Massilia is suggested. These bacteria exploit, in a transient way, a window of opportunity within the succession of communities within this niche.

  18. Ecology of root colonizing Massilia (Oxalobacteraceae).

    Science.gov (United States)

    Ofek, Maya; Hadar, Yitzhak; Minz, Dror

    2012-01-01

    Ecologically meaningful classification of bacterial populations is essential for understanding the structure and function of bacterial communities. As in soils, the ecological strategy of the majority of root-colonizing bacteria is mostly unknown. Among those are Massilia (Oxalobacteraceae), a major group of rhizosphere and root colonizing bacteria of many plant species. The ecology of Massilia was explored in cucumber root and seed, and compared to that of Agrobacterium population, using culture-independent tools, including DNA-based pyrosequencing, fluorescence in situ hybridization and quantitative real-time PCR. Seed- and root-colonizing Massilia were primarily affiliated with other members of the genus described in soil and rhizosphere. Massilia colonized and proliferated on the seed coat, radicle, roots, and also on hyphae of phytopathogenic Pythium aphanidermatum infecting seeds. High variation in Massilia abundance was found in relation to plant developmental stage, along with sensitivity to plant growth medium modification (amendment with organic matter) and potential competitors. Massilia absolute abundance and relative abundance (dominance) were positively related, and peaked (up to 85%) at early stages of succession of the root microbiome. In comparison, variation in abundance of Agrobacterium was moderate and their dominance increased at later stages of succession. In accordance with contemporary models for microbial ecology classification, copiotrophic and competition-sensitive root colonization by Massilia is suggested. These bacteria exploit, in a transient way, a window of opportunity within the succession of communities within this niche.

  19. Herbicidal activity of Pennisetum purpureum (Napier grass)

    African Journals Online (AJOL)

    Yomi

    2012-03-20

    Mar 20, 2012 ... Although, it had no phytotoxic activity on the root or shoot growth of bioassay species, it had ... mays and Eleusine indica seedlings by 11, 31, 37 and. 54%, respectively ..... might provide chemical basis for the development of.

  20. Effect of Trinexapac-Ethyl and Traffic Stress on Physiological and Morphological Characteristics of Wheat Grass(Agropyron desertorum

    Directory of Open Access Journals (Sweden)

    M. H. Sheikh Mohamadi

    2015-06-01

    Full Text Available In order to evaluate the effect of trinexapac ethyl concentrations (0, 250 and 500 g/h and traffic stress (traffic and non traffic treatments on wheat grass physiological and morphological traits, an experiment was conducted on research farm of Isfahan University of Technology in 2011 - 2012 as factorial in completely randomized designs with three replications. The studied traits involved plant height and plant density, shoot dry weight and fresh weights, tillering, chlorophyll level, roots and shoot dissolved carbohydrates. Results showed that Trinexapac ethyl reduced plant height, fresh weight and dry weight of cut parts significantly. Application of 250 and 500 g/h Trinexapac ethyl decreased plant height by 21.23 percent and 31.85 percent respectively. Application of Trinexapac ethyl improved plant height, tillering and chlorophyll level. In contrast, chlorophyll level was decreased substantially under traffic treatment and this treatment did not affect wheat grass density and tillering significantly. Under 500 g/h Trinexapac ethyl treatment, tillering was increased by 36 percent compared with under control condition one. Results showed that Trinexapac ethyl application and traffic increased dissolved carbohydrates of root and shoot significantly. As a result, it was found that wheat grass is a traffic resistant plant and it seems that the use of Trinexapac ethyl increases plant resistance to traffic stress

  1. Why rooting fails

    OpenAIRE

    Creutz, Michael

    2007-01-01

    I explore the origins of the unphysical predictions from rooted staggered fermion algorithms. Before rooting, the exact chiral symmetry of staggered fermions is a flavored symmetry among the four "tastes." The rooting procedure averages over tastes of different chiralities. This averaging forbids the appearance of the correct 't Hooft vertex for the target theory.

  2. Rooting gene trees without outgroups: EP rooting.

    Science.gov (United States)

    Sinsheimer, Janet S; Little, Roderick J A; Lake, James A

    2012-01-01

    Gene sequences are routinely used to determine the topologies of unrooted phylogenetic trees, but many of the most important questions in evolution require knowing both the topologies and the roots of trees. However, general algorithms for calculating rooted trees from gene and genomic sequences in the absence of gene paralogs are few. Using the principles of evolutionary parsimony (EP) (Lake JA. 1987a. A rate-independent technique for analysis of nucleic acid sequences: evolutionary parsimony. Mol Biol Evol. 4:167-181) and its extensions (Cavender, J. 1989. Mechanized derivation of linear invariants. Mol Biol Evol. 6:301-316; Nguyen T, Speed TP. 1992. A derivation of all linear invariants for a nonbalanced transversion model. J Mol Evol. 35:60-76), we explicitly enumerate all linear invariants that solely contain rooting information and derive algorithms for rooting gene trees directly from gene and genomic sequences. These new EP linear rooting invariants allow one to determine rooted trees, even in the complete absence of outgroups and gene paralogs. EP rooting invariants are explicitly derived for three taxon trees, and rules for their extension to four or more taxa are provided. The method is demonstrated using 18S ribosomal DNA to illustrate how the new animal phylogeny (Aguinaldo AMA et al. 1997. Evidence for a clade of nematodes, arthropods, and other moulting animals. Nature 387:489-493; Lake JA. 1990. Origin of the metazoa. Proc Natl Acad Sci USA 87:763-766) may be rooted directly from sequences, even when they are short and paralogs are unavailable. These results are consistent with the current root (Philippe H et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470:255-260).

  3. From pasture grass to cattle milk

    International Nuclear Information System (INIS)

    Miyamoto, Susumu

    1979-01-01

    Iodine-131 is one of the important fission products since it is selectively accumulated in the thyroid gland of man. The transfer of this isotope from contaminated grass to cows' milk is therefore of particular importance since milk is a major constituent of the diet especially for infants. The purpose of this paper is to discuss the transfer rate of this isotope from grass to milk of lactuating cows and its distribution in milk. It is said that the orally administered iodide is rapidly absorbed through the rumen wall and excreted mainly to urine. The absorbed iodine is accumulated highly in the thyroid gland and the considerable amount is secreted to milk. Garner et al. showed that about 5% of a dose of 131 I was found in the milk within 7 days. The extremes were 1.43 to 16.4%. Present author obtained that 18 - 30% of the dosed 131 I was secreted into milk within 7 days, indicating somewhat higher transfer rate than that of Garner et al. It was reported that more than 90% of 131 I was found in milk serum in the ionic form. The countermeasures for diminishing 131 I in milk were also presented. (author)

  4. Genetic modification of wetland grasses for phytoremediation

    Energy Technology Data Exchange (ETDEWEB)

    Czako, M.; Liang Dali; Marton, L. [Dept. of Biological Sciences, Univ. of South Carolina, Columbia, SC (United States); Feng Xianzhong; He Yuke [National Lab. of Plant Molecular Genetics, Shanghai Inst. of Plant Physiology, Chinese Academy of Sciences, Shanghai, SH (China)

    2005-04-01

    Wetland grasses and grass-like monocots are very important natural remediators of pollutants. Their genetic improvement is an important task because introduction of key transgenes can dramatically improve their remediation potential. Tissue culture is prerequisite for genetic manipulation, and methods are reported here for in vitro culture and micropropagation of a number of wetland plants of various ecological requirements such as salt marsh, brackish water, riverbanks, and various zones of lakes and ponds, and bogs. The monocots represent numerous genera in various families such as Poaceae, Cyperaceae, Juncaceae, and Typhaceae. The reported species are in various stages of micropropagation and Arundo donax is scaled for mass propagation for selecting elite lines for pytoremediation. Transfer of key genes for mercury phytoremediation into the salt marsh cordgrass (Spartina alterniflora) is also reported here. All but one transgenic lines contained both the organomercurial lyase (merB) and mercuric reductase (merA) sequences showing that co-introduction into Spartina of two genes from separate Agrobacterium strains is possible. (orig.)

  5. Factors influencing seed germination in Cerrado grasses

    Directory of Open Access Journals (Sweden)

    Rosana Marta Kolb

    2016-03-01

    Full Text Available Few studies address the ecology of herbs of Cerrado grasslands, which are ecosystems where the long dry season, high temperatures, insolation, fire and invasive grasses greatly influencing germination and the establishment of plants. We assessed germination of 13 species of Poaceae from Cerrado grasslands under nursery conditions or in germination chambers, the latter with i recently collected seeds and seeds after six months storage, ii under constant and alternating temperatures, and iii in the presence and absence of light. Germinability, mean germination time (MGT and required light were quantified to elucidate factors involved in successful germination. Germinability was low for most grasses, probably because of low seed viability. For most species, germinability and MGT were not altered by seed storage. Germination percentages were higher at alternating temperatures and in the presence of light, factors that are more similar to natural environmental situations compared with constant temperature or the absence of light. Our findings indicate that alternating temperatures and light incidence are key factors for germination of species of Poaceae. The maintenance of these environmental factors, which are crucial for the conservation of Cerrado grasslands, depends on appropriate management interventions, such as fire management and the control of biological invasion.

  6. Elephant grass clones for silage production

    Directory of Open Access Journals (Sweden)

    Rerisson José Cipriano dos Santos

    2013-02-01

    Full Text Available Ensiling warm-season grasses often requires wilting due to their high moisture content, and the presence of low-soluble sugars in these grasses usually demands the use of additives during the ensiling process. This study evaluated the bromatological composition of the fodder and silage from five Pennisetum sp. clones (IPA HV 241, IPA/UFRPE Taiwan A-146 2.114, IPA/UFRPE Taiwan A-146 2.37, Elephant B, and Mott. The contents of 20 Polyvinyl chloride (PVC silos, which were opened after 90 days of storage, were used for the bromatological analysis and the evaluation of the pH, nitrogen, ammonia, buffer capacity, soluble carbohydrates, and fermentation coefficients. The effluent losses, gases and dry matter recovery were also calculated. Although differences were observed among the clones (p < 0.05 for the concentrations of dry matter, insoluble nitrogen in acid detergents, insoluble nitrogen in neutral detergents, soluble carbohydrates, fermentation coefficients, and in vitro digestibility in the forage before ensiling, no differences were observed for most of these variables after ensiling. All of the clones were efficient in the fermentation process. The IPA/UFRPE TAIWAN A-146 2.37 clone, however, presented a higher dry matter concentration and the best fermentation coefficient, resulting in a better silage quality, compared to the other clones.

  7. Perennial Grass Bioenergy Cropping on Wet Marginal Land

    NARCIS (Netherlands)

    Das, Srabani; Teuffer, Karin; Stoof, Cathelijne R.; Walter, Michael F.; Walter, M.T.; Steenhuis, Tammo S.; Richards, Brian K.

    2018-01-01

    The control of soil moisture, vegetation type, and prior land use on soil health parameters of perennial grass cropping systems on marginal lands is not well known. A fallow wetness-prone marginal site in New York (USA) was converted to perennial grass bioenergy feedstock production. Quadruplicate

  8. Analysis of Fusarium causing dermal toxicosis in marram grass planters

    NARCIS (Netherlands)

    Snijders, CHA; Samson, RA; Hoekstra, ES; Ouellet, T; Miller, JD; deRooijvanderGoes, PCEM; Baar, AJM; Dubois, AEJ; Kauffman, HF

    1996-01-01

    In the European coastal dunes, marram grass (Ammophila arenaria) is planted in order to control sand erosion. In the years 1986 to 1991, workers on the Wadden islands in the Netherlands planting marram grass showed lesions of skin and mucous membranes, suggesting a toxic reaction. Fusarium culmorum

  9. Conceptual model for reinforced grass on inner dike slopes

    NARCIS (Netherlands)

    Verhagen, H.J.; ComCoast

    2005-01-01

    A desk study has been carried out in order to develop a conceptual model for the erosion of inner dike slopes with reinforced grass cover. Based on the results the following can be concluded: The presence of a geosynthetic in a grass slope can be taken into account in the EPM method by increasing

  10. Grass defoliation affecting survival and growth of seedlings of ...

    African Journals Online (AJOL)

    Two experiments were conducted, one in the field and the other in the greenhouse, to investigate the effects of the intensity and frequency of grass defoliation on the survival and growth of Acacia karroo seedlings. In the greenhouse, seedlings growing with heavily clipped grasses had higher biomass production than those ...

  11. Defoliation effects of perennial grasses – continuing confusion | DL ...

    African Journals Online (AJOL)

    Although an adequate knowledge of growth patterns and defoliation effects in perennial grasses is a prerequisite for the rational use of veld and pastures for animal production, our knowledge of this subject is far from adequate. The results of various physiological and clipping studies on tropical and sub-tropical grasses are ...

  12. EBIPM | Finding the Tools to Manage Invasive Annual Grasses

    Science.gov (United States)

    management decisions for a given landscape based on ecological principles. Take a look at our video " Grass Management How much could prevention save you? Guidelines to Implement EBIPM Weed Prevention Areas Grass Facts/ID The EBIPM Model Crooked River Weed Management Area Guide Tools for Educators EBIPM High

  13. Lessons learned in managing alfalfa-grass mixtures

    Science.gov (United States)

    Grass-alfalfa mixtures have a number of benefits that make them attractive to producers. However, they can be problematic to establish and maintain. Research programs have made progress in understanding the benefits and challenges of alfalfa-grass mixtures. Mixtures may have greater winter survival ...

  14. Effect of grass species on NDF ruminal degradability and ...

    African Journals Online (AJOL)

    uzivatel

    Abstract. The objective of this study was to compare the ruminal degradability of neutral detergent fibre (NDF) .... Felina were evaluated in the present study. The grass was harvested from the primary growth of monocultured grasses on 19 and 26 May of 2004 and 27 May and 10 ...... Nutritional Ecology of the Ruminant.

  15. Soil nitrogen mineralization not affected by grass species traits

    Science.gov (United States)

    Maged Ikram Nosshi; Jack Butler; M. J. Trlica

    2007-01-01

    Species N use traits was evaluated as a mechanism whereby Bromus inermis (Bromus), an established invasive, might alter soil N supply in a Northern mixed-grass prairie. We compared soils under stands of Bromus with those from three representative native grasses of different litter C/N: Andropogon...

  16. Seed production and establishment of western Oregon native grasses

    Science.gov (United States)

    Dale C. Darris

    2005-01-01

    It is well understood that native grasses are ecologically important and provide numerous benefits. However, unfavorable economics, low seed yields for some species, genetic issues, and a lack of experience behind the production and establishment of most western Oregon native grasses remain significant impediments for their expanded use. By necessity, adaptation of...

  17. Analysis of Some Heavy Metals in Grass ( Paspalum Orbiculare ...

    African Journals Online (AJOL)

    The increased deposition of trace metals from vehicle exhausts on plants has raised concerns about the risks of the quality of food consumed by humans since the heavy metals emitted through the exhaust by vehicles can enter food chain through deposition on grass grazed by animals. Grass (Paspalum Orbiculare) and ...

  18. Identification of grazed grasses using epidermal characters | R ...

    African Journals Online (AJOL)

    The use of anatomical features of the abaxial epidermis of grasses is discussed for the identification of fragments of epidermis present in samples of rumen. The reliability of this technique, and the variation of the epidermal characters in two widely distributed species of grass, is given. A "Key" to identity certain genera of ...

  19. Invasive grasses change landscape structure and fire behavior in Hawaii

    Science.gov (United States)

    Lisa M. Ellsworth; Creighton M. Litton; Alexander P. Dale; Tomoaki Miura

    2014-01-01

    How does potential fire behavior differ in grass-invaded non-native forests vs open grasslands? How has land cover changed from 1950–2011 along two grassland/forest ecotones in Hawaii with repeated fires? A study on non-native forest with invasive grass understory and invasive grassland (Megathyrsus maximus) ecosystems on Oahu, Hawaii, USA was...

  20. Seasonal variations of cadmium and zinc in Arrhenatherum elatius, a perennial grass species from highly contaminated soils

    International Nuclear Information System (INIS)

    Deram, Annabelle; Denayer, Franck-Olivier; Petit, Daniel; Van Haluwyn, Chantal

    2006-01-01

    There is interest in studying bioaccumulation in plants because they form the base of the food chain as well as their potential use in phytoextraction. From this viewpoint, our study deals with the seasonal variation, from January to July, of Cd and Zn bioaccumulation in three metallicolous populations of Arrhenatherum elatius, a perennial grass with a high biomass production. In heavily polluted soils, while Zn bioaccumulation is weak, A. elatius accumulates more Cd than reported gramineous plants, with concentration of up to 100 μg g -1 . Our results also showed seasonal variations of bioaccumulation, underlying the necessity for in situ studies to specify the date of sampling and also the phenology of the collected plant sample. In our experimental conditions, accumulation is lower in June, leading us to the hypothesis of restriction in heavy metals translocation from roots to aerial parts during seed production. - Cd and Zn bioaccumulation varies seasonally in a perennial grass

  1. Seasonal variations of cadmium and zinc in Arrhenatherum elatius, a perennial grass species from highly contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Deram, Annabelle [Institut Lillois d' Ingenierie de la Sante, Universite Droit et Sante de Lille, EA 2690, 42 rue Ambroise Pare, 59120 Loos (France)]. E-mail: aderam@ilis.univ-lille2.fr; Denayer, Franck-Olivier [Institut Lillois d' Ingenierie de la Sante, Universite Droit et Sante de Lille, EA 2690, 42 rue Ambroise Pare, 59120 Loos (France); Petit, Daniel [Laboratoire de Genetique et Evolution des Populations Vegetales, UPRESA-CNRS 8016, Bat SN2, Universite des Sciences et Techniques de Lille, 59655 Villeneuve d' Ascq, F59655 France (France); Van Haluwyn, Chantal [Faculte des Sciences Pharmaceutiques et Biologiques, Departement de Botanique, Universite Droit et Sante de Lille, EA 2690, B.P. 83, 59006 Lille Cedex (France)

    2006-03-15

    There is interest in studying bioaccumulation in plants because they form the base of the food chain as well as their potential use in phytoextraction. From this viewpoint, our study deals with the seasonal variation, from January to July, of Cd and Zn bioaccumulation in three metallicolous populations of Arrhenatherum elatius, a perennial grass with a high biomass production. In heavily polluted soils, while Zn bioaccumulation is weak, A. elatius accumulates more Cd than reported gramineous plants, with concentration of up to 100 {mu}g g{sup -1}. Our results also showed seasonal variations of bioaccumulation, underlying the necessity for in situ studies to specify the date of sampling and also the phenology of the collected plant sample. In our experimental conditions, accumulation is lower in June, leading us to the hypothesis of restriction in heavy metals translocation from roots to aerial parts during seed production. - Cd and Zn bioaccumulation varies seasonally in a perennial grass.

  2. The incidence of Pyrenochaeta terrestris in root of different plant species in Serbia

    Directory of Open Access Journals (Sweden)

    Lević Jelena T.

    2013-01-01

    Full Text Available Root samples of cereals (oats, wheat, barley, maize and sorghum, vegetables (garlic, onion, pepper, cucumber, pumpkin, carrot and tomato, industrial plant (soya bean and weeds (Johnson grass, barnyard grass and green bristle-grass collected in different agroecological conditions in Serbia were analysed for the presence of Pyrenochaeta terrestris. The fungus was found in 42 out of 51 samples (82.4%, while the incidence varied from 2.5 to 72.5%. The highest incidence was detected in cereals (average 30.3%, and then in weeds of the Poaceae family (average 14.2%. Considering single species, maize (up to 72.5% in root and Johnson grass (up to 37.5% were mostly attacked by this fungus. The lowest incidence of the fungus was determined in vegetable crops (average 6.7%. Red to reddish discoloration of root was correlated with the incidence of the fungus. Obtained data indicate that P. terrestris is widespread in Serbia and conditions for its development are favourable. [Projekat Ministarstva nauke Republike Srbije, br. TR-31023

  3. Responses of Szarvasi-1 energy grass to sewage sludge treatments in hydroponics.

    Science.gov (United States)

    Rév, Ambrus; Tóth, Brigitta; Solti, Ádám; Sipos, Gyula; Fodor, Ferenc

    2017-09-01

    Sewage sludge (SS) originating from communal wastewater is a hazardous material but have a potentially great nutritive value. Its disposal after treatment in agricultural lands can be a very economical and safe way of utilization once fast growing, high biomass, perennial plants of renewable energy production are cultivated. Szarvasi-1 energy grass (Elymus elongatus subsp. ponticus cv. Szarvasi-1), a good candidate for this application, was grown in hydroponics in order to assess its metal accumulation and tolerance under increasing SS amendments. The applied SS had a composition characteristic to SS from communal wastes and did not contain any toxic heavy metal contamination from industrial sludge in high concentration. Toxic effects was assessed in quarter strength Hoagland nutrient solution and only the two highest doses (12.5-18.75 g dm -3 ) caused decreases in root growth, shoot water content and length and stomatal conductance whereas shoot growth, root water content, chlorophyll concentration and the maximal quantum efficiency of photosystem II was unaffected. Shoot K, Ca, Mg, Mn, Zn and Cu content decreased but Na and Ni increased in the shoot compared to the unamended control. The nutritive effect was tested in 1/40 strength Hoagland solution and only the highest dose (12.5 g dm -3 ) decreased root growth and stomatal conductance significantly while lower doses (1.25-6.25 g dm -3 ) had a stimulative effect. Shoot K, Na, Fe and Ni increased and Ca, Mg, Mn, Zn and Cu decreased in this treatment. It was concluded that SS with low heavy metal content can be a potentially good fertilizer for high biomass non-food crops such as Szarvasi-1 energy grass. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  4. Soil amendment effects on the exotic annual grass Bromus tectorum L. and facilitation of its growth by the native perennial grass Hilaria jamesii (Torr.) Benth

    Science.gov (United States)

    Belnap, J.; Sherrod, S.K.

    2009-01-01

    Greenhouse experiments were undertaken to identify soil factors that curtail growth of the exotic annual grass Bromus tectorum L. (cheatgrass) without significantly inhibiting growth of native perennial grasses (here represented by Hilaria jamesii [Torr.] Benth). We grew B. tectorum and H. jamesii alone (monoculture pots) and together (combination pots) in soil treatments that manipulated levels of soil phosphorus, potassium, and sodium. Hilaria jamesii showed no decline when its aboveground biomass in any of the applied treatments was compared to the control in either the monoculture or combination pots. Monoculture pots of B. tectorum showed a decline in aboveground biomass with the addition of Na2HPO4 and K2HPO4. Interestingly, in pots where H. jamesii was present, the negative effect of these treatments was ameliorated. Whereas the presence of B. tectorum generally decreased the aboveground biomass of H. jamesii (comparing aboveground biomass in monoculture versus combination pots), the presence of H. jamesii resulted in an enhancement of B. tectorum aboveground biomass by up to 900%. We hypothesize that B. tectorum was able to obtain resources from H. jamesii, an action that benefited B. tectorum while generally harming H. jamesii. Possible ways resources may be gained by B. tectorum from native perennial grasses include (1) B. tectorum is protected from salt stress by native plants or associated soil biota; (2) when B. tectorum is grown with H. jamesii, the native soil biota is altered in a way that favors B. tectorum growth, including B. tectorum tapping into the mycorrhizal network of native plants and obtaining resources from them; (3) B. tectorum can take advantage of root exudates from native plants, including water and nutrients released by natives via hydraulic redistribution; and (4) B. tectorum is able to utilize some combination of the above mechanisms. In summary, land managers may find adding soil treatments can temporarily suppress B. tectorum

  5. Modelling the transfer of 14C from the atmosphere to grass: A case study in a grass field near AREVA-NC La Hague

    International Nuclear Information System (INIS)

    Aulagnier, C.; Le Dizès, S.; Maro, D.; Hébert, D.; Lardy, R.; Martin, R.; Gonze, M.-A.

    2012-01-01

    Radioactive 14 C is formed as a by-product of nuclear power generation and from operation of nuclear fuel reprocessing plants like AREVA-NC La Hague (North France), which releases about 15 TBq per year of 14 C into the atmosphere. Since the autumn of 2006, 14 C activity concentrations in samples from the terrestrial environment (air, grass and soil) have been monitored monthly on grassland 2 km downwind of the reprocessing plant. The monitoring data provides an opportunity to validate radioecology models used to assess 14 C transfer to grassland ecosystems. This article compares and discusses the ability of two different models to reproduce the observed temporal variability in grass 14 C activity in the vicinity of AREVA-NC La Hague. These two models are the TOCATTA model which is specifically designed for modelling transfer of 14 C and tritium in the terrestrial environment, and PaSim, a pasture model for simulating grassland carbon and nitrogen cycling. Both TOCATTA and PaSim tend to under-estimate the magnitude of observed peaks in grass 14 C activity, although they reproduce the general trends. PaSim simulates 14 C activities in substrate and structural pools of the plant. We define a mean turn-over time for 14 C within the plant, which is based on both experimental data and the frequency of cuts. An adapted PaSim result is presented using the 15 and 20 day moving average results for the 14 C activity in the substrate pool, which shows a good match to the observations. This model reduces the Root Mean Square Error (RMSE) by nearly 40% in comparison to TOCATTA. - Highlights: ► We model 14 C transfer from the atmosphere to grass near AREVA-NC reprocessing plant. ► Both models considered under-estimate the observed variability and highest peaks. ► A model based solely on the sap 14 C activity and mean turn-over time is considered. ► It performs well and could be applied to case studies around nuclear facilities.

  6. Establishing native warm season grasses on Eastern Kentucky strip mines

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, T.G.; Larkin, J.L.; Arnett, M.B. [Univ. of Kentucky, Lexington, KY (United States). Dept. of Forestry

    1998-12-31

    The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomass samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife habitat.

  7. Establishing native warm season grasses on Eastern Kentucky strip mines

    International Nuclear Information System (INIS)

    Barnes, T.G.; Larkin, J.L.; Arnett, M.B.

    1998-01-01

    The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomass samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife habitat

  8. Rumen escape protein in grass and grass silage deterimened with a nylon bag and an enzymatic technique

    NARCIS (Netherlands)

    Cone, J.W.; Gelder, van A.H.; Mathijssen-Kamman, A.A.; Hindle, V.A.

    2004-01-01

    Rumen escape protein (REP) was determined for six grasses and 16 grass silages using a nylon bag technique and an in vitro technique using a proteolytic enzyme preparation of Streptomyces griseus. In vitro, the samples were incubated for 0, 1, 6 and 24 h. The highest correlation observed between

  9. EroGRASS : Failure of grass cover layers at seaward and shoreward dike slopes. design, construction and performance

    NARCIS (Netherlands)

    Verhagen, H.J.; Verheij, H.J.; Cao, T.M.; Dassanayake, D.; Roelvink, D.; Piontkowitz, T.

    2009-01-01

    A large number of the dikes in the North Sea and Baltic Sea regions are covered with grass that is exposed to hydraulic loading from waves and currents during storm surges. During previous storm surges the grass cover layers often showed large strength and remained undamaged. A clear physical

  10. Established native perennial grasses out-compete an invasive annual grass regardless of soil water and nutrient availability

    Science.gov (United States)

    Christopher M. McGlone; Carolyn Hull Sieg; Thomas E. Kolb; Ty Nietupsky

    2012-01-01

    Competition and resource availability influence invasions into native perennial grasslands by nonnative annual grasses such as Bromus tectorum. In two greenhouse experiments we examined the influence of competition, water availability, and elevated nitrogen (N) and phosphorus (P) availability on growth and reproduction of the invasive annual grass B. tectorum and two...

  11. The dehydration stress of couch grass is associated with its lipid metabolism, the induction of transporters and the re-programming of development coordinated by ABA.

    Science.gov (United States)

    Janská, Anna; Svoboda, Pavel; Spiwok, Vojtěch; Kučera, Ladislav; Ovesná, Jaroslava

    2018-05-02

    The wild relatives of crop species represent a potentially valuable source of novel genetic variation, particularly in the context of improving the crop's level of tolerance to abiotic stress. The mechanistic basis of these tolerances remains largely unexplored. Here, the focus was to characterize the transcriptomic response of the nodes (meristematic tissue) of couch grass (a relative of barley) to dehydration stress, and to compare it to that of the barley crown formed by both a drought tolerant and a drought sensitive barley cultivar. Many of the genes up-regulated in the nodes by the stress were homologs of genes known to be mediated by abscisic acid during the response to drought, or were linked to either development or lipid metabolism. Transporters also featured prominently, as did genes acting on root architecture. The resilience of the couch grass node arise from both their capacity to develop an altered, more effective root architecture, but also from their formation of a lipid barrier on their outer surface and their ability to modify both their lipid metabolism and transporter activity when challenged by dehydration stress. Our analysis revealed the nature of dehydration stress response in couch grass. We suggested the tolerance is associated with lipid metabolism, the induction of transporters and the re-programming of development coordinated by ABA. We also proved the applicability of barley microarray for couch grass stress-response analysis.

  12. The Physiological, Morphological and Bio-Chemical Comparison of the Current Grass Shiraz City’s Green Space withTall Fescue (Festuca arundinacea Schreb

    Directory of Open Access Journals (Sweden)

    M. Zadehbagheri

    2016-02-01

    Full Text Available One of the main problems of Shiraz city’s green space is the change of color and visual quality of turf during cold months. Therefore, we aimed to evaluate tall fescue in order to find if it is suitable for replacement. This experiment was in the form of complete random blocks and it was done during two consecutive years. Each treatment had 4 repetitions. Data were analyzed using SPSS software, version 16.0, and the means were compared using t or LSD tests at a significance level of 5%. The results showed that tall fescue was superior to normal sport grass in cold months with respect to its chlorophyll, catalase, protein, prolin, and soluble sugar content, as well as its visual quality and root depth. Prolin fluctuations in tall fescue were very high which showed that these types of grass can increase the plant’s prolin content under stress. Therefore, there is a fivefold increase in the prolin content of the grass in cold months (cold tension compared to the beginning of spring (best condition for growth. However, this change does not exist in sport grass. Based on the obtained results we can conclude that tall fescue can resist environmental tension, especially coldness, using different mechanisms, and is a good substitute for normal sport grass.

  13. EFFECT OF DROUGHT STRESS AND ADDITION OF ARBUSCULA MYCORRHIZAL FUNGI (AMF ON GROWTH AND PRODUCTIVITY OF TROPICAL GRASSES (Chloris gayana, Paspalum dilatatum, and Paspalum notatum

    Directory of Open Access Journals (Sweden)

    Pebriansyah A

    2014-06-01

    Full Text Available Grasses productivity is affected by soil water availability. Arbuscular Mycorrhizal Fungi (AMF was innoculated to support plant to overcome drought stress during its growth. The aim of this study was to understand the role of  Arbuscular Mycorrhizal Fungi (AMF to support growth and the production of grasses in drought stress condition. Three species of tropical grasses : Chloris    gayana,    Paspalum    notatum,    and  Paspalum dilatatum were used. The research used completely randomized design with 4 treatments consisting of M0S0 = without AMF and daily watering, M0S1 = without AMF and without watering; M1S0 = with mycorrhiza and daily watering; M1S1 = with AMF and without watering. and 5 replications. The four treatments research were as follows; Each type of grasses were obsereved in a separate study. The result showed that AMF played significant role in improving growth and root dry weight biomass of Chloris    gayana in drought condition. Paspalum notatum is the most adaptive grass in the drought condition. Chloris gayana has the growth and a better production than Paspalum dilatatum.

  14. Linking root hydraulic properties to carbon allocation patterns in annual plant

    Science.gov (United States)

    Hosseini, A.; Ewers, B. E.; Adjesiwor, A. T.; Kniss, A. R.

    2017-12-01

    Incorporation of root structure and function into biophysical models is an important tool to predict plant water and nutrient uptake from the soil, plant carbon (C) assimilation, partitioning and release to the soils. Most of the models describing root water uptake (RWU) are based on semi-empirical (i.e. built on physiological hypotheses, but still combined with empirical functions) approaches and hydraulic parameters involved are hardly available. Root conductance is essential to define the interaction between soil-to-root and canopy-to-atmosphere. Also root hydraulic limitations to water flow can impact gas exchange rates and plant biomass partitioning. In this study, sugar beet (B. vulgaris) seeds under two treatments, grass (Kentucky bluegrass) and no grass (control), were planted in 19 L plastic buckets in June 2016. Photosynthetic characteristics (e.g. gas exchange and chlorophyll fluorescence), leaf morphology and anatomy, root morphology and above and below ground biomass of the plants was monitored at 15, 30, 50, 70 and 90 days after planting (DAP). Further emphasis was placed on the limits to water flow by coupling of hydraulic conductance (k) whole root-system with water relation parameters and gas exchange rates in fully established plants.

  15. Homogenous stands of a wetland grass harbour diverse consortia of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Wirsel, Stefan G R

    2004-05-01

    A molecular approach was applied to investigate the colonisation of arbuscular mycorrhizal fungi (AMF) on the wetland grass Phragmites australis. A PCR assay targeting the traditional families of the Glomeromycota yielded products that were used to construct libraries of 18S rDNA. Five hundred and forty six clones were typed by restriction analysis and 76 representatives were sequenced. The majority corresponded to a wide range of taxa within Glomus group A, a few belonged to the "Diversisporaceae" and none to the genera Scutellospora or Acaulospora. Among these sequences, some were very similar to those reported earlier, e.g. Glomus mosseae and G. fasciculatum, other pointed to various new taxa. Although this wetland habitat harboured just one single plant species, phylogenetic analysis exhibited 21 AMF phylotypes, which is in the same range as reported for other natural ecosystems composed of more diverse host communities. Diversity indices supported the perception that the AMF mycoflora associated with this natural grass "monoculture" is not depauperate as it had been described for grasses of crop monocultures. Soil conditions determined the mycorrhizal state of the host, since AMF were not detected at the lakeward front of the reed belt, which is permanently waterlogged.

  16. Perrenial Grasses for Sustainable European Protein Production

    DEFF Research Database (Denmark)

    Jørgensen, Uffe; Lærke, Poul Erik

    2016-01-01

    reduction goals for agriculture. Denmark has an especially vulnerable aquatic environment due to sandy soils, a long coast line, and high precipitation. Thus, fulfilling the WFD means some areas must halve their nitrate leaching, and radical changes are required to reduce losses while maintaining profitable...... crop production. National scenarios show that up to ten million tonnes of additional biomass can be sourced in Denmark without reducing food production or increasing the area under cultivation if a biorefinery industry is established. In one of the scenarios optimized for additional environmental...... in the “environment” scenario. This scenario was achieved by converting approx. 9 % of agricultural land from annual crops into perennial grass. New experimental results support the anticipated increase in total biomass yield and reduction in nitrate leaching, when converting land currently used for grain crop...

  17. Different Phylogenetic and Environmental Controls of First-order Root Morphological and Chemical Traits

    Science.gov (United States)

    Wang, R.; Wang, Q.; Zhao, N.; Yu, G.; He, N.

    2017-12-01

    Fine roots are the most distal roots that act as the primary belowground organs in acquiring limiting nutrients and water from the soil. However, limited by the inconsistency in definitions of fine roots and the different protocols among studies, knowledge of root system traits has, to date, still lagged far behind our understanding of above-ground traits. In particular, whether variation in fine root traits among the plant species along a single root economics spectrum and this underlying mechanism are still hotly debated. In this study, we sampled the first-order root using the standardized protocols, and measured six important root traits related to resource use strategies, from 181 plant species from subtropical to boreal forests. Base on this large dataset, we concluded that different phylogenetic and environmental factors affected on root thickness and nutrient, resulting in the decoupled pattern between them. Specifically, variation in species-level traits related to root thickness (including root diameter, RD and specific root length, SRL) was restricted by common ancestry and little plastic to the changing environments, whereas the large-scale variation in woody root nutrient was mainly controlled by environmental differences, especially soil variables. For community-level traits, mean annual temperature (MAT) mainly influenced the community-level root thickness through the direct effect of changes in plant species composition, while soil P had a positive influence effect on community-level root nitrogen concentration (CWM_RN), reflecting the strong influence of soil fertility on belowground root nutrient. The different environmental constraints and selective pressures acting between root thickness and nutrient traits allows for multiple ecological strategies to adapt to complex environmental conditions. In addition, strong relationships between community-level root traits and environmental variables, due to environmental filters, indicate that in contrast

  18. Indigenous knowledge of Rural Communities for Combating Climate ...

    African Journals Online (AJOL)

    HP

    and extremes, suppress diseases and crop pests and usd to conserve soil moisture so as to increase ..... materials such as leaves, grass clippings, kitchen scraps and yard wastes. As a result, ... consumption in urban and rural communities.

  19. Uptake of 2,4,6-Trinitrotoluene (TNT) by Vetiver grass (Vetiviera ziznoides L.) -- Preliminary results from a hydroponic study

    Science.gov (United States)

    Shakya, K. M.; Sarkar, D.; Datta, R.; Makris, K.; Pachanoor, D.

    2006-05-01

    2,4,6-Trinitrotoluene(TNT) is a potent mutagen and a Group C human carcinogen that has been widely used to produce munitions and explosives. As a result, vast areas that have been previously used as military ranges, munition burning and open detonation sites have been heavily contaminated with TNT. Conventional remedial activities in such contaminated sites commonly rely on methods such as incineration, land filling and soil composting. Phytoremediation offers a cost-effective solution, utilizing plants to phytoextract TNT from the contaminated soil. We propose the use of vetiver grass (Vetiveria zizanoides) to remove TNT from such contaminated soils. Vetiver is a fast-growing and adaptive grass, enabling its use in TNT-contaminated sites in a wide variety of soil types and climate. We also hypothesized that TNT removal by vetiver grass will be enhanced by utilizing a chaotropic agent (urea) to alter rhizosphere/root hair chemical environment. The objectives of this preliminary hydroponic study were: i) to investigate the effectiveness of vetiver grass in removing TNT from solution, and ii) to evaluate the use of a common agrochemical (urea) in enhancing TNT removal by vetiver grass. Vetiver plants were grown in a hydroponic system with five different TNT concentrations (0, 5, 10, 25, and 50 mg TNT L-1) and three urea concentrations (0, 0.01 and 0.1%). A plant density of 10 g L-1 and three replicate vessels per treatment were used. Aliquots were collected at several time intervals up to 192 hour, and were analyzed for TNT with HPLC. Results showed that vetiver was able to remove TNT from hydroponic solutions. The overall magnitude and kinetics of TNT removal by vetiver grass was enhanced in the presence of urea. TNT removal kinetics depended on TNT and urea initial concentrations, suggestive of second-order kinetic reactions. Preliminary results are encouraging, but in need for verification using more detailed studies involving TNT-contaminated soils. Ongoing

  20. Genetic association among root morphology, root quality and root yield in ashwagandha (Withania somnifera)

    OpenAIRE

    Kumar Ramesh R.; Reddy Anjaneya Prasanna L.; Subbaiah Chinna J.; Kumar Niranjana A.; Prasad Nagendra H.N.; Bhukya Balakishan

    2011-01-01

    Ashwagandha (Withania somnifera) is a dryland medicinal crop and roots are used as valuable drug in traditional systems of medicine. Morphological variants (morphotypes) and the parental populations were evaluated for root - morphometric, quality and yield traits to study genetic association among them. Root morphometric traits (root length, root diameter, number of secondary roots/ plant) and crude fiber content exhibited strong association among them and ...

  1. The Social Roots of a Global Community

    Science.gov (United States)

    Soholt, Polli

    2015-01-01

    Polli Soholt points to normalization in the first plane as leading to the successful realization of the human personality, which is the basis of social development. Children who have cultivated concentration and purposeful work at an early age develop the virtues to become world citizens. Normalization can be assisted by certain practices: 1)…

  2. Decomposition of 14C-labeled roots in a pasture soil exposed to 10 years of elevated CO2

    NARCIS (Netherlands)

    Groenigen, van C.J.; Gorissen, A.; Six, J.; Harris, D.; Kuikman, P.J.; Groenigen, van J.W.; Kessel, van C.

    2005-01-01

    The net flux of soil C is determined by the balance between soil C input and microbial decomposition, both of which might be altered under prolonged elevated atmospheric CO2. In this study, we determined the effect of elevated CO2 on decomposition of grass root material (Lolium perenne L.).

  3. Endoscopic root canal treatment.

    Science.gov (United States)

    Moshonov, Joshua; Michaeli, Eli; Nahlieli, Oded

    2009-10-01

    To describe an innovative endoscopic technique for root canal treatment. Root canal treatment was performed on 12 patients (15 teeth), using a newly developed endoscope (Sialotechnology), which combines an endoscope, irrigation, and a surgical microinstrument channel. Endoscopic root canal treatment of all 15 teeth was successful with complete resolution of all symptoms (6-month follow-up). The novel endoscope used in this study accurately identified all microstructures and simplified root canal treatment. The endoscope may be considered for use not only for preoperative observation and diagnosis but also for active endodontic treatment.

  4. RUNTIME DICTIONARIES FOR ROOT

    CERN Document Server

    Wind, David Kofoed

    2013-01-01

    ROOT is the LHC physicists' common tool for data analysis; almost all data is stored using ROOT's I/O system. This system benefits from a custom description of types (a so-called dictionary) that is optimised for the I/O. Until now, the dictionary cannot be provided at run-time; it needs to be prepared in a separate prerequisite step. This project will move the generation of the dictionary to run-time, making use of ROOT 6's new just-in-time compiler. It allows a more dynamic and natural access to ROOT's I/O features especially for user code.

  5. Creationism at the grass roots: A study of a local creationist institution

    Science.gov (United States)

    Wendel, Paul J.

    Relying on the book of Genesis as a source text, young-earth creationists or "creation scientists" claim to find physical evidence that the earth was created in six 24-hour periods less than ten thousand years ago and that most of the geologic column was laid down in a year-long worldwide flood. Unsurprisingly, these claims lead to a boundary dispute over the definition of science, in which mainstream scientists impugn the validity of creation science and creation scientists respond in kind. Although young-earth creationism is a growing movement, little is known about it. In particular, little is known about how creationists view the relationship between creationism and science or how the rhetoric of moral, cultural, environmental, and/or biological decline informs creationist practice. In order to investigate these issues, I studied the Fossil Museum (pseudonym), a local young-earth creationist institution, through a combination of naturalistic inquiry and visitor interviews. With respect to the rhetoric of decline, I found that cultural, environmental, and biological decline appear to function independently of one another in Fossil Museum rhetoric. With respect to views of the relationship between creationism and science, I found that despite having limited training or experience in science and despite committing numerous scientific errors, Fossil Museum associates respect and emulate science. Believing that physical evidence mediated by honest science will vindicate young-earth creationism, Fossil Museum associates speak of science in highly Baconian terms, invoking the ideal of assumption-free data and privileging observation over inference. They also accept the notion that science should be falsifiable and they suggest that on this criterion, mainstream science is not scientific. Yet because of their belief that physical evidence can vindicate their position, they openly discuss counterevidence to young-earth creationism, regarding such counterevidence as anomalies for future resolution rather than occasions for crisis. I conclude that because of Fossil Museum associates' honest approach to physical data and their belief that science can resolve disputes, productive dialogue is possible and desirable between mainstream scientists and some young-earth creationists, but such dialogue will be useful only if it is aimed at mutual understanding rather than mutual conversion.

  6. 26 CFR 56.4911-3 - Expenditures for direct and/or grass roots lobbying communications.

    Science.gov (United States)

    2010-04-01

    .... The other advertisement contains only the membership and fundraising appeals, along with a general... advertising in various media and by pamphlets distributed in various areas. P annually provides its literature...

  7. 26 CFR 56.4911-2 - Lobbying expenditures, direct lobbying communications, and grass roots lobbying communications.

    Science.gov (United States)

    2010-04-01

    ... rebuttable presumption regarding certain paid mass media communications) and § 56.4911-5 (special, more... mass media communications about highly publicized legislation. Paragraph (d) of this section contains... the farm economy. The advertisement is not a mass media communication described in paragraph (b)(5)(ii...

  8. Symbiosis in the Context of an Invasive, Non-Native Grass: Fungal Biodiversity and Student Engagement

    Science.gov (United States)

    Lehr, Gavin

    Grasslands in the western United States face severe environmental threats including those brought about by climate change, such as changes in precipitation regimes and altered fire cycles; land-use conversion and development; and the introduction, establishment, and spread of non-native species. Lehmann's lovegrass (Eragrostis lehmanniana) was introduced to the southwestern United States in the early 1900s. Since its introduction, it has become the dominant grass in the mid-elevation grasslands of southern Arizona, including the Santa Rita Experimental Range (SRER), where it has displaced native grasses including Arizona cottontop, three awns, and gramas. Like all plants in terrestrial ecosystems, this grass harbors fungal symbionts that can be important for its establishment and persistence. This thesis focuses on fungal symbionts of Lehmann's lovegrass and has two components. First, the diversity and distributions of endophytes in Lehmann's lovegrass are evaluated in the context of biotic and abiotic factors in the SRER. Culturing from roots and shoots of Lehmann's lovegrass at points beneath and outside the canopy of native mesquites, which are encroaching on grasslands over time, provides insight into how a single plant species can exhibit local variation in the composition of its symbionts. Second, the thesis is used as the basis for engagement of students in science, technology, engineering, and mathematics (STEM) through the development and implementation of classroom- and field activities centered on endophytes, which help high school students address core learning aims while also gaining real research experience. Engaging students in important questions relevant to their local environment can catalyze interest in science and help students cross the threshold into research. The contributions of such approaches with respect to learning not only fulfills key next-generation science standards and common core objectives, but provides students with a meaningful

  9. Influence of soil fertility on waterlogging tolerance of two Brachiaria grasses

    Directory of Open Access Journals (Sweden)

    Juan de la Cruz Jiménez

    2015-04-01

    Full Text Available As a consequence of global warming, rainfall is expected to increase in several regions around the world. This, together with poor soil drainage, will result in waterlogged soil conditions. Brachiaria grasses are widely sown in the tropics and, these grasses confront seasonal waterlogged conditions. Several studies have indicated that an increase in nutrient availability could reduce the negative impact of waterlogging. Therefore, an outdoor study was conducted to evaluate the responses of two Brachiaria sp. grasses with contrasting tolerances to waterlogging, B. ruziziensis (sensitive and B. humidicola (tolerant, with two soil fertility levels. The genotypes were grown with two different soil fertilization levels (high and low and under well-drained or waterlogged soil conditions for 15 days. The biomass production, chlorophyll content, photosynthetic efficiency, and macro- (N, P, K, Ca, Mg and S and micronutrient (Fe, Mn, Cu, Zn and B contents in the shoot tissue were determined. Significant differences in the nutrient content of the genotypes and treatments were found. An increase of redoximorphic elements (Fe and Mn in the soil solution occurred with the waterlogging. The greater tolerance of B. humidicola to waterlogged conditions might be due to an efficient root system that is able to acquire nutrients (N, P, K and potentially exclude phytotoxic elements (Fe and Mn under waterlogged conditions. A high nutrient availability in the waterlogged soils did not result in an improved tolerance for B. ruziziensis. The greater growth impairment seen in the B. ruziziensis with high soil fertility and waterlogging (as opposed to low soil fertility and waterlogging was possibly due to an increased concentration of redoximorphic elements under these conditions.

  10. Environmental performance assessment of Napier grass for bioenergy production

    DEFF Research Database (Denmark)

    Nimmanterdwong, Prathana; Chalermsinsuwan, Benjapon; Østergård, Hanne

    2017-01-01

    equivalence. This idea provides the quantitative indicators involving the resource use and the percent renewability of the systems. For the proposed biorefinery model, Napier grass (Pennisetum purpureum) grown in Thailand was used as lignocellulosic feedstock. An emergy assessment was performed in two parts...... cultivation and biorefinery stages. For Napier grass cultivation, most of the emergy support came from local resources in term of evapotranspiration of Napier grass (33%) and the diesel consumption during the cultivation process (21%). The emergy sustainability indicator of the cultivation was 0...

  11. The effects of energy grass plantations on biodiversity

    Energy Technology Data Exchange (ETDEWEB)

    Semere, T; Slater, F

    2005-07-01

    The ecological impact on local wildlife of biomass plantations of three different species of grasses has been monitored in the years 2002 to 2004 inclusive at farms in Herefordshire UK. Two of the grasses were not native to Britain. Wildlife monitored included ground flora, beetles, insects, birds, small mammals, butterflies, bees and hoverflies. The results provide a baseline of biodiversity data from biomass farms in England, although due to poor crop growth, the data from the switch-grass plantation was incomplete. The surveys were carried out by Cardiff University supported financially by the DTI.

  12. The effects of energy grass plantations on biodiversity

    International Nuclear Information System (INIS)

    Semere, T.; Slater, F.

    2005-01-01

    The ecological impact on local wildlife of biomass plantations of three different species of grasses has been monitored in the years 2002 to 2004 inclusive at farms in Herefordshire UK. Two of the grasses were not native to Britain. Wildlife monitored included ground flora, beetles, insects, birds, small mammals, butterflies, bees and hoverflies. The results provide a baseline of biodiversity data from biomass farms in England, although due to poor crop growth, the data from the switch-grass plantation was incomplete. The surveys were carried out by Cardiff University supported financially by the DTI

  13. Effect of Vetiver Grass on Reduction of Soil Salinity and Some Minerals

    Directory of Open Access Journals (Sweden)

    Masoud Noshadi

    2017-02-01

    Full Text Available Introduction: Soil salinity is one of the major limitations of agriculture in the warm and dry regions. Soil sodification also damages soil structure and reduce soil permeability. Therefore, control of soil salinity and sodium is very important. Vetiver grass has unique characteristics that can be useful in phytoremediation. Materials and Methods: This research was conducted to investigate the effects of irrigation with different salinities on vetiver grass and the effects of this plant on the control of soil salinity and soil reclamation.The experimental design was randomized complete block design. Irrigation water salinities were 0.68(blank, 2, 4, 6, 8 and 10 dS/m, respectively, which artificially were constructed using sodium chloride and calcium chloride. At first, vetiver was transplanted and then moved to the farm. The amount of soil moisture was measured by the neutron probe. Irrigation depth was applied to refill soil water deficit up to field capacity. To evaluate the soil salinity in above salinity treatments, soil was sampled in each plot from 0-30, 30-60 and 60-90 cm depths and for each layer, electrical conductivity of saturated extract (ECe, sodium, potassium and chloride concentrations was measured .To measure the sodium, potassium and chloride concentrations in the leaves and roots of vetiver plant, samples were dried in oven. The dried samples were powdered and passed through the sieve (No. 200 and they were reduced to ash in 250 ◦C. 5 ml HCl was added to one gram of the ash, and after passing through filter paper, the volume of sample was brought to 50 ml by boiled distilled water. After preparing plant samples, the sodium, potassium and chloride concentrations were measured by Flame Photometer. Reults and discussion: The results showed that the vetiver grass was able to decrease soil salinity at different salinity levels except highest water salinity (10 dS/m and prevented salt accumulation in the soil. However, in the

  14. Phosphorus effect on the uptake, translocation and accumulation of the 14C-urea in orchard grass (Dactylis glomerata L.)

    International Nuclear Information System (INIS)

    Panak, H.; Nowak, G.; Nowak, J.; Akademia Rolniczo-Technicza, Olsztyn

    1981-01-01

    The effect of different phosphorus supplies on the uptake, translocation and accumulation of 14 C-urea by orchard grass was investigated. Phosphorus starvation inhibits the uptake, translocation and accumulation of the carbon of urea similarly to the nitrogen of urea. As compared with the uptake process the reduction of the accumulation is much more effected by the inhibition of the carbon translocation from roots to the aboveground parts. Lack of phosphorus also decreases the incorporation of the 14 C of urea into high-molecular compounds. The effect of phosphorus deficit on the accumulation of 14 C-urea increases with time of starvation. (orig.)

  15. Exudation of fluorescent beta-carbolines from Oxalis tuberosa L roots.

    Science.gov (United States)

    Bais, Harsh Pal; Park, Sang-Wook; Stermitz, Frank R; Halligan, Kathleen M; Vivanco, Jorge M

    2002-11-01

    Root fluorescence is a phenomenon in which roots of seedlings fluoresce when irradiated with ultraviolet (UV) light. Soybean (Glycine max) and rye grass (Elymus glaucus) are the only plant species that have been reported to exhibit this occurrence in germinating seedling roots. The trait has been useful as a marker in genetic, tissue culture and diversity studies, and has facilitated selection of plants for breeding purposes. However, the biological significance of this occurrence in plants and other organisms is unknown. Here we report that the Andean tuber crop species Oxalis tuberosa, known as oca in the highlands of South America, secretes a fluorescent compound as part of its root exudates. The main fluorescent compounds were characterized as harmine (7-methoxy-1-methyl-beta-carboline) and harmaline (3, 4-dihydroharmine). We also detected endogenous root fluorescence in other plant species, including Arabidopsis thaliana and Phytolacca americana, a possible indication that this phenomenon is widespread within the plant kingdom.

  16. Linking root traits and competitive success in grassland species

    NARCIS (Netherlands)

    Ravenek, Janneke M.; Mommer, Liesje; Visser, Eric J.W.; Ruijven, van Jasper; Paauw, van der Jan Willem; Smit-Tiekstra, Annemiek; Caluwe, de Hannie; Kroon, de Hans

    2016-01-01

    Background and aims: Competition is an important force shaping plant communities. Here we test the hypothesis that high overall root length density and selective root placement in nutrient patches, as two alternative strategies, confer competitive advantage in species mixtures. Methods: We

  17. Root structure-function relationships in 74 species: evidence of a root economics spectrum related to carbon economy.

    Science.gov (United States)

    Roumet, Catherine; Birouste, Marine; Picon-Cochard, Catherine; Ghestem, Murielle; Osman, Normaniza; Vrignon-Brenas, Sylvain; Cao, Kun-Fang; Stokes, Alexia

    2016-05-01

    Although fine roots are important components of the global carbon cycle, there is limited understanding of root structure-function relationships among species. We determined whether root respiration rate and decomposability, two key processes driving carbon cycling but always studied separately, varied with root morphological and chemical traits, in a coordinated way that would demonstrate the existence of a root economics spectrum (RES). Twelve traits were measured on fine roots (diameter ≤ 2 mm) of 74 species (31 graminoids and 43 herbaceous and dwarf shrub eudicots) collected in three biomes. The findings of this study support the existence of a RES representing an axis of trait variation in which root respiration was positively correlated to nitrogen concentration and specific root length and negatively correlated to the root dry matter content, lignin : nitrogen ratio and the remaining mass after decomposition. This pattern of traits was highly consistent within graminoids but less consistent within eudicots, as a result of an uncoupling between decomposability and morphology, and of heterogeneity of individual roots of eudicots within the fine-root pool. The positive relationship found between root respiration and decomposability is essential for a better understanding of vegetation-soil feedbacks and for improving terrestrial biosphere models predicting the consequences of plant community changes for carbon cycling. © 2016 CNRS. New Phytologist © 2016 New Phytologist Trust.

  18. Root strength of tropical plants - An investigation in the Western Ghats of Kerala, India

    Science.gov (United States)

    Lukose Kuriakose, S.; van Beek, L. P. H.; van Westen, C. J.

    2009-04-01

    Earlier research on debris flows in the Tikovil River basin of the Western Ghats concluded that root cohesion is significant in maintaining the overall stability of the region. In this paper we present the most recent results (December 2008) of root tensile strength tests conducted on nine species of plants that are commonly found in the region. They are 1) Rubber (Hevea Brasiliensis), 2) Coconut Palm (Cocos nucifera), 3) Jackfruit trees (Artocarpus heterophyllus), 4) Teak (Tectona grandis), 5) Mango trees (Mangifera indica), 6) Lemon grass (Cymbopogon citratus), 7) A variety of Tamarind (Garcinia gummigutta), 8) Coffee (Coffea Arabica) and Tea (Camellia sinensis). About 1500 samples were collected of which only 380 could be tested (in the laboratory) due to breakage of roots during the tests. In the successful tests roots failed in tension. Roots having diameters between 2 mm and 12 mm were tested. Each sample tested has a length of 15 cm. Results indicate that the roots of Coffee, Tamarind, Lemon grass and Jackfruit are the strongest of the nine plant types tested whereas Tea and Teak plants had the most fragile roots. Coconut roots behaved atypical to the others, as the bark of the roots was crushed and slipped from the clamp when tested whereas its internal fiber was the strongest of all tested. Root tensile strength decreases with increasing diameters, Rubber showing more ductile behaviour than Coffee and Tamarind that behaved more brittle, root tensile strength increasing exponentially for finer roots. Teak and Tea showed almost a constant root tensile strength over the range of diameters tested and little variability. Jack fruit and mango trees showed the largest variability, which may be explained by the presence of root nodules, preventing the derivation of an unequivocal relationship between root diameters and tensile strength. This results in uncertainty of root strength estimates that are applicable. These results provide important information to

  19. The Effect of Soil Type and Moisture Content on Head Impacts on Natural Grass Athletic Fields

    Directory of Open Access Journals (Sweden)

    Kyley Dickson

    2018-02-01

    Full Text Available Studies are warranted to evaluate head injury criterion (HIC on athletic fields to determine baseline numbers and compare those findings to current critical thresholds for impact attenuation. A two year (2016 and 2017 study was conducted on University of Tennessee athletic fields (Knoxville, TN, USA to determine the effect of soil type (cohesive soil, United States Golf Association sand specifications and grass species (Poa pratensis and Cynodon dactylon × C. transvaalensis on HIC. Additionally soil moisture conditions monitored were: dry (0.06–0.16 m3/m3, acceptable (0.17–0.29 m3/m3, and wet (0.30–0.40 m3/m3. A linear relationship (r = 0.91 was identified between drop height (0.5–2.9 M and HIC value (35-1423 HIC on granular root zones of both grass types. However, HIC on cohesive soil is a function of soil water content in addition to drop height. These results demonstrate to aid in head injury prevention on cohesive soil athletic fields the HIC can be lowered by managing soil water content.

  20. Energy evaluation of fresh grass in the diets of lactating dairy cows

    NARCIS (Netherlands)

    Bruinenberg, M.H.; Zom, R.L.G.; Valk, H.

    2002-01-01

    The discrepancy between the estimated feeding value of fresh grass and the output per kg grass in terms of milk and maintenance was studied by evaluating 12 experiments with grass-fed dairy cows. The percentage grass in the diets varied between 40 and 90. Intake and milk production were recorded

  1. Quantification of fructan concentration in grasses using NIR spectroscopy and PLSR

    DEFF Research Database (Denmark)

    Shetty, Nisha; Gislum, Rene

    2011-01-01

    Near-infrared reflectance (NIR) spectroscopy combined with chemometrics was used to quantify fructan concentration in samples from seven grass species. Savitzky-Golay first derivative with filter width 7 and polynomial order 2 with mean centering was applied as a spectral pre-treatment method...... to remove unimportant baseline signals. In order to model the NIR spectroscopy data the partial least squares regression (PLSR) approach was used on the full spectra. Variable selection based on PLSR by jack-knifing within a cross-model validation (CMV) framework was applied in order to remove non...... quantification of fructans by NIR spectroscopy is possible and that jack-knifing PLSR within a CMV framework is an effective way to eliminate the wavelengths of no interest. Jack-knifing PLSR did not improve the predictive ability because the root mean square error of prediction (RMSEP) increased (1.37) compared...

  2. N transfer in three species grass-clover mixtures with chicory, ribwort plantain or caraway

    DEFF Research Database (Denmark)

    Dhamala, Nawa Raj; Rasmussen, Jim; Carlsson, Georg

    2017-01-01

    Background and aimsThere is substantial evidence that legume-derived Nitrogen (N) is transferred to neighboring non-legumes in grassland mixtures. However, there is sparse information about how deep rooted non-legume forage herbs (forbs) influence N transfer in multi-species grasslands. Methodology......Red clover (Trifolium pretense L.) was grown together with perennial ryegrass (Lolium perenne L.) and one of three forb species: chicory (Cichorium intybus L.), ribwort plantain (Plantago lanceolata L.) or caraway (Carum carvi L.) in a field experiment. During the first year after the establishment, red...... clover leaves were labeled with 15N-urea to determine the N transfer from red clover to companion ryegrass and forbs. ResultsOn an annual basis, up to 15 % of red clover N was transferred to the companion ryegrass and forbs, but predominantly to the grass. The forb species did not differ in their ability...

  3. Effects of Infection by Belonolaimus longicaudatus on Rooting Dynamics among St. Augustinegrass and Bermudagrass Genotypes.

    Science.gov (United States)

    Aryal, Sudarshan K; Crow, William T; McSorley, Robert; Giblin-Davis, Robin M; Rowland, Diane L; Poudel, Bishow; Kenworthy, Kevin E

    2015-12-01

    Understanding rooting dynamics using the minirhizotron technique is useful for cultivar selection and to quantify nematode damage to roots. A 2-yr microplot study including five bermudagrass ('Tifway', Belonolaimus longicaudatus susceptible; two commercial cultivars [TifSport and Celebration] and two genotypes ['BA132' and 'PI 291590'], which have been reported to be tolerant to B. longicaudatus) and two St. Augustinegrass ('FX 313', susceptible, and 'Floratam' that was reported as tolerant to B. longicaudatus) genotypes in a 5 x 2 and 2 x 2 factorial design with four replications, respectively, was initiated in 2012. Two treatments included were uninoculated and B. longicaudatus inoculated. In situ root images were captured each month using a minirhizotron camera system from April to September of 2013 and 2014. Mixed models analysis and comparison of least squares means indicated significant differences in root parameters studied across the genotypes and soil depths of both grass species. 'Celebration', 'TifSport' and 'PI 291590' bermudagrass, and 'Floratam' St. Augustinegrass had significantly different root parameters compared to the corresponding susceptible genotypes (P ≤ 0.05). Only 'TifSport' had no significant root loss when infested with B. longicaudatus compared to non-infested. 'Celebration' and 'PI 291590' had significant root loss but retained significantly greater root densities than 'Tifway' in B. longicaudatus-infested conditions (P ≤ 0.05). Root lengths were greater at the 0 to 5 cm depth followed by 5 to 10 and 10 to 15 cm of vertical soil depth for both grass species (P ≤ 0.05). 'Celebration', 'TifSport', and 'PI 291590' had better root vigor against B. longicaudatus compared to Tifway.

  4. Irrational Square Roots

    Science.gov (United States)

    Misiurewicz, Michal

    2013-01-01

    If students are presented the standard proof of irrationality of [square root]2, can they generalize it to a proof of the irrationality of "[square root]p", "p" a prime if, instead of considering divisibility by "p", they cling to the notions of even and odd used in the standard proof?

  5. Brassinosteroid Mediated Cell Wall Remodeling in Grasses under Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Xiaolan Rao

    2017-05-01

    Full Text Available Unlike animals, plants, being sessile, cannot escape from exposure to severe abiotic stresses such as extreme temperature and water deficit. The dynamic structure of plant cell wall enables them to undergo compensatory changes, as well as maintain physical strength, with changing environments. Plant hormones known as brassinosteroids (BRs play a key role in determining cell wall expansion during stress responses. Cell wall deposition differs between grasses (Poaceae and dicots. Grass species include many important food, fiber, and biofuel crops. In this article, we focus on recent advances in BR-regulated cell wall biosynthesis and remodeling in response to stresses, comparing our understanding of the mechanisms in grass species with those in the more studied dicots. A more comprehensive understanding of BR-mediated changes in cell wall integrity in grass species will benefit the development of genetic tools to improve crop productivity, fiber quality and plant biomass recalcitrance.

  6. Effect of machinery wheel load on grass yield

    DEFF Research Database (Denmark)

    Green, Ole; Jørgensen, Rasmus Nyholm; Kristensen, Kristian

    2010-01-01

    Effect of machinery wheel load on grass   Ole Green1, Rasmus N. Jørgensen2, Kristian Kristensen3, René Gislum3, Dionysis Bochtis1, & Claus G. Sørensen1   1University of Aarhus, Dept. of Agricultural Engineering 2University of Southern Denmark, Inst. of Chemical Eng., Biotechnology and Environmental...... 3University of Aarhus, Dept. of Genetics and Biotechnology   Corresponding author: Ole Green Address & e-mail: Research Centre Foulum, Blichers Allé 20, 8830 Tjele. Ole.Green@agrsci.dk     Abstract   Different traffic intensities have been shown to have a negative influence on the yield of grass...... and clover. A full scale grass-clover field trial was established to estimate the effect on clover-grass yields as a function of different wheel loads and tire pressures. The trial comprised 16 different traffic intensities with 35 replicates and 1 traffic free treatment with 245 replicates, totalling 17...

  7. Seasonal variation in diurnal atmospheric grass pollen concentration profiles

    DEFF Research Database (Denmark)

    Peel, Robert George; Ørby, Pia Viuf; Skjøth, Carsten Ambelas

    2014-01-01

    the time of day when peak concentrations are most likely to occur using seasonally averaged diurnal profiles. Atmospheric pollen loads are highly dependent upon emissions, and different species of grass are known to flower and emit pollen at different times of the day and during different periods......In this study, the diurnal atmospheric grass pollen concentration profile within the Danish city of Aarhus was shown to change in a systematic manner as the pollen season progressed. Although diurnal grass pollen profiles can differ greatly from day-to-day, it is common practice to establish...... of the pollen season. Pollen concentrations are also influenced by meteorological factors - directly through those parameters that govern pollen dispersion and transport, and indirectly through the weather-driven flowering process. We found that three different profiles dominated the grass pollen season...

  8. The design and development of GRASS file reservation system

    International Nuclear Information System (INIS)

    Huang Qiulan; Zhu Suijiang; Cheng Yaodong; Chen Gang

    2010-01-01

    GFRS (GRASS File Reservation System) is designed to improve the file access performance of GRASS (Grid-enabled Advanced Storage System) which is a Hierarchical Storage Management (HSM) system developed at Computing Center, Institute of High Energy Physics. GRASS can provide massive storage management and data migration, but the data migration policy is simply based factors such as pool water level, the intervals for migration and so on, so it is short of precise control over files. As for that, we design GFRS to implement user-based file reservation which is to reserve and keep the required files on disks for High Energy physicists. CFRS can improve file access speed for users by avoiding migrating frequently accessed files to tapes. In this paper we first give a brief introduction of GRASS system and then detailed architecture and implementation of GFRS. Experiments results from GFRS have shown good performance and a simple analysis is made based on it. (authors)

  9. Designing a New Raster Sub-System for GRASS-7

    Directory of Open Access Journals (Sweden)

    Martin Hruby

    2012-03-01

    Full Text Available The paper deals with a design of a new raster sub-system intended for modern GIS systems open for client and server operation, database connection and strong application interface (API. Motivation for such a design comes from the current state of API working in GRASS 6. If found attractive, the here presented design and its implementation (referred as RG7 may be integrated to the future new generation of the GRASS Geographical Information System version 7-8. The paper describes in details the concept of raster tiling, computer storage of rasters and basic raster access procedures. Finally, the paper gives a simple benchmarking experiment of random read access to raster files imported from the Spearfish dataset. The experiment compares the early implementation of RG7 with the current implementation of rasters in GRASS 6. As the result, the experiment shows the RG7 to be significantly faster than GRASS in random read access to large raster files.

  10. Grass survey of the Itremo Massif records endemic central highland ...

    African Journals Online (AJOL)

    Grasses are members of the plant family Poaceae, and are primar- ily known for their ... Madagascar Conservation & Development is the journal of. Indian Ocean .... cording to the classification by Kellogg (2015). With 64 ..... Flowering plants.

  11. Root phenology at Harvard Forest and beyond

    Science.gov (United States)

    Abramoff, R. Z.; Finzi, A.

    2013-12-01

    maximum growth period. In contrast, root growth was characterized by multiple production peaks. Q. rubra root growth experienced many small flushes around day of year (DOY) 156 (early June) and one large peak on 234 (late August). T. canadensis root growth peaked on DOY 188 (early July), 234.5 (late August) and 287 (mid-October). However, particular phenological patterns varied widely from site to site. Despite large spatial heterogeneity, it appears that Q. rubra experiences greater overall root production as well as more allocation to roots during the growing season. The storage pool of nonstructural carbohydrates experiences a mid-summer drawdown in Q. rubra but not T. canadensis roots. Timing of belowground C allocation to root growth and nonstructural carbohydrate accumulation may be regulated by climate factors as well as endogenous factors such as vessel size, growth form, or tradeoffs in C allocated between plant organs. Plant roots supply substrate to microbial communities and hence their production feeds back to other plant and soil processes that affect ecosystem C fluxes.

  12. Sonoran Desert ecosystem transformation by a C4 grass without the grass/fire cycle

    Science.gov (United States)

    Olsson, Aaryn D.; Betancourt, Julio; McClaran, Mitchel P.; Marsh, Stuart E.

    2012-01-01

    Aim Biological invasions facilitate ecosystem transformation by altering the structure and function, diversity, dominance and disturbance regimes. A classic case is the grass–fire cycle in which grass invasion increases the frequency, scale and/or intensity of wildfires and promotes the continued invasion of invasive grasses. Despite wide acceptance of the grass–fire cycle, questions linger about the relative roles that interspecific plant competition and fire play in ecosystem transformations. Location Sonoran Desert Arizona Upland of the Santa Catalina Mountains, Arizona, USA. Methods We measured species cover, density and saguaro (Carnegiea gigantea) size structure along gradients of Pennisetum ciliare invasion at 10 unburned/ungrazed P. ciliare patches. Regression models quantified differences in diversity, cover and density with respect to P. ciliare cover, and residence time and a Fisher's exact test detected demographic changes in saguaro populations. Because P. ciliare may have initially invaded locations that were both more invasible and less diverse, we ran analyses with and without the plots in which initial infestations were located. Results Richness and diversity decreased with P. ciliare cover as did cover and density of most dominant species. Richness and diversity declined with increasing time since invasion, suggesting an ongoing transformation. The proportion of old-to-young Carnegiea gigantea was significantly lower in plots with dominant P. ciliare cover. Main conclusions Rich desert scrub (15–25 species per plot) was transformed into depauperate grassland (2–5 species per plot) within 20 years following P. ciliare invasion without changes to the fire regime. While the onset of a grass–fire cycle may drive ecosystem change in the later stages and larger scales of grass invasions of arid lands, competition by P. ciliare can drive small-scale transformations earlier in the invasion. Linking competition-induced transformation rates with

  13. Chromatic roots and hamiltonian paths

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2000-01-01

    We present a new connection between colorings and hamiltonian paths: If the chromatic polynomial of a graph has a noninteger root less than or equal to t(n) = 2/3 + 1/3 (3)root (26 + 6 root (33)) + 1/3 (3)root (26 - 6 root (33)) = 1.29559.... then the graph has no hamiltonian path. This result...

  14. BUFFEL GRASS MORPHOAGRONOMIC CHARACTERIZATION FROM Cenchrus GERMPLASM ACTIVE BANK

    OpenAIRE

    BRUNO, LEILA REGINA GOMES PASSOS; ANTONIO, RAFAELA PRISCILA; ASSIS, JOSÉ GERALDO DE AQUINO; MOREIRA, JOSÉ NILTON; LIRA, IRLANE CRISTINE DE SOUZA ANDRADE

    2017-01-01

    ABSTRACT This study aimed to characterize buffel grass accessions of the Cenchrus Germplasm Active Bank (CGAB) from Embrapa Semi-Arid in a morphoagronomic way, checking the descriptors variability and efficiency in accessions on two consecutive cuts. Twenty-five accessions and five buffel grass cultivars were used in randomized complete block design with three replications. Evaluations were conducted after two consecutive cuts, each evaluation performed 90 days after each cut. Characterizatio...

  15. Buffel grass morphoagronomic characterization from cenchrus germplasm active bank.

    OpenAIRE

    BRUNO, L. R. G. P.; ANTONIO, R. P.; ASSIS, J. G. de A.; MOREIRA, J. N.; LIRA, I. C. de S. A.

    2017-01-01

    his study aimed to characterize buffel grass accessions of the Cenchrus Germplasm Active Bank (CGAB) from Embrapa Semi - Arid in a morphoagronomic way, checking the descriptors variability and efficiency in accessions on two consecutive cuts. Twenty - five accessions and five buffel grass cultivars were used in randomized complete block design with three replications. Evaluations were conducted after two consecutive cuts, each evaluation performed 90 days after each ...

  16. Persistence of Overseeded Cool-Season Grasses in Bermudagrass Turf

    OpenAIRE

    Thomas Serensits; Matthew Cutulle; Jeffrey F. Derr

    2011-01-01

    Cool-season grass species are commonly overseeded into bermudagrass turf for winter color. When the overseeded grass persists beyond the spring; however, it becomes a weed. The ability of perennial ryegrass, Italian (annual) ryegrass, intermediate ryegrass, and hybrid bluegrass to persist in bermudagrass one year after seeding was determined. Perennial ryegrass, intermediate ryegrass, and Italian ryegrass produced acceptable ground cover in the spring after fall seeding. Hybrid bluegrass di...

  17. Postharvest residues from grass seed crops for bioenergy

    OpenAIRE

    Simić, Aleksandar; Čolić, Vladislava; Vučković, Savo; Dželetović, Željko; Bijelić, Zorica; Mandić, Violeta

    2016-01-01

    During grass seed production, a large amount of low forage quality biomass has been produced. Tall growing perennial grasses such as tall fescue (Festuca arundinacea L.) and Italian ryegrass (Lolium multiflorum Lam.) can be used as an alternative source for bioenergy production as they can be grown in less cultivated areas, their residues in seed production could be valuable energy source and can be potentially used as a dual purpose crop (bioenergy and forage). In this research, potentials o...

  18. The Potential of Cellulosic Ethanol Production from Grasses in Thailand

    Directory of Open Access Journals (Sweden)

    Jinaporn Wongwatanapaiboon

    2012-01-01

    Full Text Available The grasses in Thailand were analyzed for the potentiality as the alternative energy crops for cellulosic ethanol production by biological process. The average percentage composition of cellulose, hemicellulose, and lignin in the samples of 18 types of grasses from various provinces was determined as 31.85–38.51, 31.13–42.61, and 3.10–5.64, respectively. The samples were initially pretreated with alkaline peroxide followed by enzymatic hydrolysis to investigate the enzymatic saccharification. The total reducing sugars in most grasses ranging from 500–600 mg/g grasses (70–80% yield were obtained. Subsequently, 11 types of grasses were selected as feedstocks for the ethanol production by simultaneous saccharification and cofermentation (SSCF. The enzymes, cellulase and xylanase, were utilized for hydrolysis and the yeasts, Saccharomyces cerevisiae and Pichia stipitis, were applied for cofermentation at 35°C for 7 days. From the results, the highest yield of ethanol, 1.14 g/L or 0.14 g/g substrate equivalent to 32.72% of the theoretical values was obtained from Sri Lanka ecotype vetiver grass. When the yields of dry matter were included in the calculations, Sri Lanka ecotype vetiver grass gave the yield of ethanol at 1,091.84 L/ha/year, whereas the leaves of dwarf napier grass showed the maximum yield of 2,720.55 L/ha/year (0.98 g/L or 0.12 g/g substrate equivalent to 30.60% of the theoretical values.

  19. Grass buffers for playas in agricultural landscapes: An annotated bibliography

    Science.gov (United States)

    Melcher, Cynthia P.; Skagen, Susan K.

    2005-01-01

    This bibliography and associated literature synthesis (Melcher and Skagen, 2005) was developed for the Playa Lakes Joint Venture (PLJV). The PLJV sought compilation and annotation of the literature on grass buffers for protecting playas from runoff containing sediments, nutrients, pesticides, and other contaminants. In addition, PLJV sought information regarding the extent to which buffers may attenuate the precipitation runoff needed to fill playas, and avian use of buffers. We emphasize grass buffers, but we also provide information on other buffer types.

  20. Fate and chemical speciation of antimony (Sb) during uptake, translocation and storage by rye grass using XANES spectroscopy.

    Science.gov (United States)

    Ji, Ying; Sarret, Géraldine; Schulin, Rainer; Tandy, Susan

    2017-12-01

    Antimony (Sb) is a contaminant of increased prevalence in the environment, but there is little knowledge about the mechanisms of its uptake and translocation within plants. Here, we applied for the synchrotron based X-ray absorption near-edge structure (XANES) spectroscopy to analyze the speciation of Sb in roots and shoots of rye grass (Lolium perenne L. Calibra). Seedlings were grown in nutrient solutions to which either antimonite (Sb(III)), antimonate (Sb(V)) or trimethyl-Sb(V) (TMSb) were added. While exposure to Sb(III) led to around 100 times higher Sb accumulation in the roots than the other two treatments, there was no difference in total Sb in the shoots. Antimony taken up in the Sb(III) treatment was mainly found as Sb-thiol complexes (roots: >76% and shoots: 60%), suggesting detoxification reactions with compounds such as glutathione and phytochelatins. No reduction of accumulated Sb(V) was found in the roots, but half of the translocated Sb was reduced to Sb(III) in the Sb(V) treatment. Antimony accumulated in the TMSb treatment remained in the methylated form in the roots. By synchrotron based XANES spectroscopy, we were able to distinguish the major Sb compounds in plant tissue under different Sb treatments. The results help to understand the translocation and transformation of different Sb species in plants after uptake and provide information for risk assessment of plant growth in Sb contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Microbial diversity and metagenomic analysis of the rhizosphere of para grass (Urochloa mutica) growing under saline conditions

    International Nuclear Information System (INIS)

    Mukhtar, S.; Awan, H. A.; Maqbool, A.; Mehnaz, S.; Malik, K. A.

    2016-01-01

    Para grass is a salt tolerant plant, grown on salt affected soils of Punjab, Pakistan. The aim of this study was to investigate the distribution of culturable and non-culturable bacteria in the rhizosphere, rhizoplane and histoplane of para grass, growing under saline conditions. A total of seventy four, bacterial strains were isolated and characterized. Among these, thirty two from rhizosphere, twenty two from rhizoplane and twenty were from the histoplane. Cultureable bacteria were characterized by biochemical tests and 16S rRNA gene sequence analysis. Non-culturable bacteria were identified by PCR amplification of 16S rRNA gene, using metagenomic approach. Seventy seven percent bacterial isolates from rhizosphere and rhizoplane fractions were identified as member of Proteobacteria. Twenty five percent isolates of histoplane fraction were members of firmicutes while 68.75 percent were of Proteobacteria. Of total isolates, 50 percent could grow in nitrogen free medium and 21.67 percent on halophilic medium. Nitrogen fixers and halophilic bacteria were more abundant in the rhizosphere as compared to roots. 16S rRNA gene clone library analysis showed that out of 48 clones, 14 were uncultured, classified; eighteen un-cultured un-classified, while others related to 16 different known cultured groups of bacteria. Results for cultured and uncultured bacteria revealed a wide diversity of bacterial population present in the rhizosphere of para grass. (author)

  2. Turbulent transfer characteristics of radioiodine effluents from air to grass

    Energy Technology Data Exchange (ETDEWEB)

    Markee, E. H. [ARFRO, Environmental Science Services Administration, Idaho Falls, Idaho (United States)

    1967-07-01

    A total of 20 controlled field releases of radioiodine have been performed at the National Reactor Testing Station in Idaho as a portion of a program to study the transmission of gaseous radioiodine through the air-vegetation-cow-milk-human chain. Most of the releases were conducted over typical pasture grasses during different wind and stability conditions. Radioiodine adherence to grass and carbon plates was measured during most of the tests. Vertical air concentration profiles and turbulence parameters were measured to determine flux characteristics. Analysis of the data reveals the complex interdisciplinary nature of transfer of radioiodine from air to a natural surface. The data are in reasonable agreement with the deposition models of Sheppard and Chamberlain when corrections for the physical and biological receptiveness of the grass and grass density are made. The average ratios of momentum to mass flux were found to be 0.9 in stable conditions and 1.4 in unstable conditions. These ratios demonstrate the effect on mass flux in the lowest 4m by a surface that acts as a partial sink for gaseous effluents. This series of releases indicates the need for further research on the biological receptiveness of grass and turbulent transfer within a grass canopy. (author)

  3. Estimating grass-clover ratio variations caused by traffic intensities using image analysis

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Nyholm; Sørensen, Claus Grøn; Green, Ole

    Grass and especially clover have a negative yield response as a function of  traffic intensity.  Conventional grass-clover production for silage have high traffic intensity due to fertilizing with slurry, cutting the grass, rolling the grass into swaths, and collecting and chopping the grass...... to fulfill the aim [1]http://www.ruralni.gov.uk/index/publications/press_articles/dairy-2/role-of-clover.htm...

  4. Designing Resilient and Productive Grasses with Plasticity to Extreme Weather Events

    Science.gov (United States)

    Loka, D.; Humphreys, M.; Gwyn Jones, D.; Scullion, J.; Doonan, J.; Gasior, D.; Harper, J.; Farrell, M.; Kingston-Smith, A.; Dodd, R.; Chadwick, D.; Hill, P.; Robinson, D.; Jones, D.

    2016-12-01

    Grasslands occupy more than 70% of the world's agricultural land and are major providers of healthy feed for livestock and for ecosystem services. Global warming is projected to increase the intensity and frequency of extreme weather events such as drought and flooding and will reduce persistency of currently productive but stress sensitive forage grass varieties, thereby challenging global food security and compromising on their existing ecosystem functionality. New perennial grass varieties, tolerant to the onsets of more than one abiotic stresses, are required in order to achieve sustainable grassland production and function over years under adverse environmental conditions. Identifying and selecting reliable morphological and physiological traits associated with increased resistance to multiple stress conditions is a prerequisite to ensure future grasslands resilience. The objectives of our study were to select from diverse and novel Festulolium (ryegrass spp. x fescue spp. hybrids) grass populations capable of providing optimal combinations of good forage production together with resilience to multiple stresses and to monitor morphological and physiological responses under multiple stress conditions. The grasses were: Festulolium variety Prior (L. perenne x F. pratensis), shown to alter soil structure and hydrology to mitigate run-off and flooding; two advanced breeding populations of diploid L. perenne with genes for drought tolerance derived from the Mediterranean fescue species F. arundinacea and F. glaucescens; two tetraploid hybrid populations involving L. perenne in combination with F. glaucescens and F. mairei (from North Africa), respectively. As controls, Festulolium variety AberNiche and L. perenne variety AberWolf varieties, were used. Treatments consisted of: A) Control; plants maintained at optimum conditions, B) Flood; plants were flooded for 6 weeks followed by a 4-week recovery, C) Drought; plants received limited quantity of water for 12 weeks

  5. Growing Community Roots for the Geosciences in Miami, Florida, A Program Aimed at High School and Middle School Students to Increase Awareness of Career and Educational Opportunities in the Geosciences

    Science.gov (United States)

    Whitman, D.; Hickey-Vargas, R.; Gebelein, J.; Draper, G.; Rego, R.

    2013-12-01

    Growing Community Roots for the Geosciences is a 2-year pilot recruitment project run by the Department of Earth and Environment at Florida International University (FIU) and funded by the NSF OEDG (Opportunities for Enhancing Diversity in the Geosciences) program. FIU, the State University of Florida in Miami is a federally recognized Minority Serving Institution with over 70% of the undergraduate population coming from groups underrepresented in the geoscience workforce. The goal of this project is to inform students enrolled in the local middle and high schools to career opportunities in the geosciences and to promote pathways for underrepresented groups to university geoscience degree programs. The first year's program included a 1-week workshop for middle school teachers and a 2-week summer camp aimed at high school students in the public school system. The teacher workshop was attended by 20 teachers who taught comprehensive and physical science in grades 6-8. It included lectures on geoscience careers, fundamental concepts of solid earth and atmospheric science, hands on exercises with earth materials, fossils and microscopy, interpretation of landform with Google Earth imagery, and a field trip to a local working limestone quarry. On the first day of the workshop, participants were surveyed on their general educational background in science and their familiarity and comfort with teaching basic geoscience concepts. On the final day, the teachers participated in a group discussion where we discussed how to make geoscience topics and careers more visible in the school curriculum. The 2-week summer camp was attended by 21 students entering grades 9-12. The program included hands on exercises on geoscience and GIS concepts, field trips to local barrier islands, the Everglades, a limestone quarry and a waste to energy facility, and tours of the NOAA National Hurricane Center and the FIU SEM lab. Participants were surveyed on their general educational background

  6. Root profile in Multi-layered Dehesas: an approach to plant-to-plant Interaction

    Science.gov (United States)

    Rolo, V.; Moreno, G.

    2009-04-01

    Assessing plant-to-plant relationship is a key issue in agroforestry systems. Due to the sessile feature of plants most of these interactions take place within a restricted space, so characterizing the zone where the plant alters its environment is important to find overlapping areas where the facilitation or competition could occur. Main part of plan-to-plant interactions in the dehesa are located at belowground level, thus the main limited resources in Mediterranean ecosystems are soil nutrient and water. Hence a better knowledge of rooting plant profile can be useful to understand the functioning of the dehesa. The Iberian dehesa has always been considered as a silvopastoral system where, at least, two strata of vegetation coexist: native grasses and trees. However the dehesa is also a diverse system where cropland and encroached territories have been systematically combined, more or less periodically, with native pasture in order to obtain agricultural, pastoral and forestry outputs. These multipurpose mosaic-type systems generate several scenarios where the plant influence zone may be overlapped and the interaction, competition or facilitation, between plants can play an important role in the ecosystem functioning in terms of productivity and stability. In the present study our aim was to characterize the rooting profile of multi-layered dehesas in order to understand the competitive, and/or facilitative, relationships within the different plant strata. The root profile of Quercus ilex subsp. ballota, Cistus ladanifer, Retama spaherocarpa and natural grasses was studied. So 48 trenches, up to 2 meters deep, were excavated in 4 different environments: (i) grass; (ii) tree-grass; (iii) tree-shrub and (iv) tree-shrub-grass (12 trenches in each environment). The study was carried out in 4 dehesas, 2 encroached with C. ladanifer and 2 with R. spaherocarpa. In every trench soil samples were taken each 20 cm. Subsequently, all samples were sieved using different mesh

  7. Response of dominant grass and shrub species to water manipulation: an ecophysiological basis for shrub invasion in a Chihuahuan Desert grassland.

    Science.gov (United States)

    Throop, Heather L; Reichmann, Lara G; Sala, Osvaldo E; Archer, Steven R

    2012-06-01

    Increases in woody vegetation and declines in grasses in arid and semi-arid ecosystems have occurred globally since the 1800s, but the mechanisms driving this major land-cover change remain uncertain and controversial. Working in a shrub-encroached grassland in the northern Chihuahuan Desert where grasses and shrubs typically differ in leaf-level nitrogen allocation, photosynthetic pathway, and root distribution, we asked if differences in leaf-level ecophysiology could help explain shrub proliferation. We predicted that the relative performance of grasses and shrubs would vary with soil moisture due to the different morphological and physiological characteristics of the two life-forms. In a 2-year experiment with ambient, reduced, and enhanced precipitation during the monsoon season, respectively, the encroaching C(3) shrub (honey mesquite Prosopis glandulosa) consistently and substantially outperformed the historically dominant C(4) grass (black grama Bouteloua eriopoda) in terms of photosynthetic rates while also maintaining a more favorable leaf water status. These differences persisted across a wide range of soil moisture conditions, across which mesquite photosynthesis was decoupled from leaf water status and moisture in the upper 50 cm of the soil profile. Mesquite's ability to maintain physiologically active leaves for a greater fraction of the growing season than black grama potentially amplifies and extends the importance of physiological differences. These physiological and phenological differences may help account for grass displacement by shrubs in drylands. Furthermore, the greater sensitivity of the grass to low soil moisture suggests that grasslands may be increasingly susceptible to shrub encroachment in the face of the predicted increases in drought intensity and frequency in the desert of the southwestern USA.

  8. Post-treatment efficacy of discontinuous treatment with 300IR 5-grass pollen sublingual tablet in adults with grass pollen-induced allergic rhinoconjunctivitis

    DEFF Research Database (Denmark)

    Didier, A; Malling, H-J; Worm, Marcel

    2013-01-01

    Sustained efficacy over three pollen seasons of pre- and co-seasonal treatment with 300IR 5-grass pollen sublingual tablet has been demonstrated in adults with moderate-severe grass pollen-associated allergic rhinoconjunctivitis.......Sustained efficacy over three pollen seasons of pre- and co-seasonal treatment with 300IR 5-grass pollen sublingual tablet has been demonstrated in adults with moderate-severe grass pollen-associated allergic rhinoconjunctivitis....

  9. Preliminary Results of Clover and Grass Coverage and Total Dry Matter Estimation in Clover-Grass Crops Using Image Analysis

    Directory of Open Access Journals (Sweden)

    Anders K. Mortensen

    2017-12-01

    Full Text Available The clover-grass ratio is an important factor in composing feed ratios for livestock. Cameras in the field allow the user to estimate the clover-grass ratio using image analysis; however, current methods assume the total dry matter is known. This paper presents the preliminary results of an image analysis method for non-destructively estimating the total dry matter of clover-grass. The presented method includes three steps: (1 classification of image illumination using a histogram of the difference in excess green and excess red; (2 segmentation of clover and grass using edge detection and morphology; and (3 estimation of total dry matter using grass coverage derived from the segmentation and climate parameters. The method was developed and evaluated on images captured in a clover-grass plot experiment during the spring growing season. The preliminary results are promising and show a high correlation between the image-based total dry matter estimate and the harvested dry matter ( R 2 = 0.93 with an RMSE of 210 kg ha − 1 .

  10. Upgraded fuel from reed canary grass

    Energy Technology Data Exchange (ETDEWEB)

    Heiskanen, V P

    1996-12-31

    The feasibility of RCG for commercial utilization depends primarily on its applicability for pulp production and its use in energy production will be based on the residue that will be available after extracting the pulp fraction of the RCG. Roughly 20 ..30% of the material will be available for energy production purposes. However, the percentage may be higher/lower depending on the quality standards of the pulp fiber material. The harvesting period has a significant effect on the fuel characteristics of RCG. For instance the contents of N, S, Cl, K are clearly lower if the RCG is harvested in the spring (delayed) instead of summer/autumn. These elements affect significantly overall emission formation and ash behaviour and its melting temperature. The combustion related research in this project has been focused on the spring-harvested RCG. The project aims to evaluate the feasibility of delayed harvested RCG for energy production. In order to reach this goal, the following combustion methods will be tested and studied: combustion of pelletized RCG; gasification; combustion of pulverized RCG. In addition, pelletizing, reactivity and NO conversion of pulverized RCG will be studied. The research described here is a part of `Reed Canary Grass` project (in AIR programme). The contractors of the project are Swedish University of Agricultural Sciences (coordinator), United Milling Systems from Denmark, Jaakko Poeyry Oy and VTT Energy. In addition, there are partners from several countries participating in the project. The project has been divided in five tasks, VTT Energy being responsible for combustion related task `Upgraded fuel` that includes the research topics discussed in this paper

  11. Upgraded fuel from reed canary grass

    Energy Technology Data Exchange (ETDEWEB)

    Heiskanen, V.P.

    1995-12-31

    The feasibility of RCG for commercial utilization depends primarily on its applicability for pulp production and its use in energy production will be based on the residue that will be available after extracting the pulp fraction of the RCG. Roughly 20 ..30% of the material will be available for energy production purposes. However, the percentage may be higher/lower depending on the quality standards of the pulp fiber material. The harvesting period has a significant effect on the fuel characteristics of RCG. For instance the contents of N, S, Cl, K are clearly lower if the RCG is harvested in the spring (delayed) instead of summer/autumn. These elements affect significantly overall emission formation and ash behaviour and its melting temperature. The combustion related research in this project has been focused on the spring-harvested RCG. The project aims to evaluate the feasibility of delayed harvested RCG for energy production. In order to reach this goal, the following combustion methods will be tested and studied: combustion of pelletized RCG; gasification; combustion of pulverized RCG. In addition, pelletizing, reactivity and NO conversion of pulverized RCG will be studied. The research described here is a part of `Reed Canary Grass` project (in AIR programme). The contractors of the project are Swedish University of Agricultural Sciences (coordinator), United Milling Systems from Denmark, Jaakko Poeyry Oy and VTT Energy. In addition, there are partners from several countries participating in the project. The project has been divided in five tasks, VTT Energy being responsible for combustion related task `Upgraded fuel` that includes the research topics discussed in this paper

  12. GRASS GIS: The first Open Source Temporal GIS

    Science.gov (United States)

    Gebbert, Sören; Leppelt, Thomas

    2015-04-01

    GRASS GIS is a full featured, general purpose Open Source geographic information system (GIS) with raster, 3D raster and vector processing support[1]. Recently, time was introduced as a new dimension that transformed GRASS GIS into the first Open Source temporal GIS with comprehensive spatio-temporal analysis, processing and visualization capabilities[2]. New spatio-temporal data types were introduced in GRASS GIS version 7, to manage raster, 3D raster and vector time series. These new data types are called space time datasets. They are designed to efficiently handle hundreds of thousands of time stamped raster, 3D raster and vector map layers of any size. Time stamps can be defined as time intervals or time instances in Gregorian calendar time or relative time. Space time datasets are simplifying the processing and analysis of large time series in GRASS GIS, since these new data types are used as input and output parameter in temporal modules. The handling of space time datasets is therefore equal to the handling of raster, 3D raster and vector map layers in GRASS GIS. A new dedicated Python library, the GRASS GIS Temporal Framework, was designed to implement the spatio-temporal data types and their management. The framework provides the functionality to efficiently handle hundreds of thousands of time stamped map layers and their spatio-temporal topological relations. The framework supports reasoning based on the temporal granularity of space time datasets as well as their temporal topology. It was designed in conjunction with the PyGRASS [3] library to support parallel processing of large datasets, that has a long tradition in GRASS GIS [4,5]. We will present a subset of more than 40 temporal modules that were implemented based on the GRASS GIS Temporal Framework, PyGRASS and the GRASS GIS Python scripting library. These modules provide a comprehensive temporal GIS tool set. The functionality range from space time dataset and time stamped map layer management

  13. Measurement of unsaturated flow below the root zone at an arid site

    International Nuclear Information System (INIS)

    Kirkham, R.R.; Gee, G.W.

    1983-12-01

    We measured moisture content changes below the root zone of a grass-covered area at the Hanford Site in Washington State and determined that drainage exceeded 5 cm or 20% of the total precipitation for November 1982 through October 1983. Although the average annual rainfall at the Hanford Site is 16 cm, the test year precipitation exceeded 24 cm with nearly 75% of the precipitation occurring during November through April. The moisture content at all depths in the soil reached a maximum and the monthly average potential evapotranspiration reached a minimum during this period of time. Moisture content profiles were measured at depth on biweekly intervals from January through October; these data were used to estimate drainage from the profile. Grass roots were not found below 1 m, hence moisture changes below 1 m were assumed to be entirely due to drainage. Upward capillary flow was considered to be negligible since the soil was a coars sand and the water table was below 10 m. The large amount of drainage from this arid site is attributed to rainfall distribution pattern, shallow root-zone, and soil drainage characteristics. Unsaturated flow model simulations predicted about 5-cm drainage from the grass site using daily climatic data, estimated soil hydraulic properties, and estimated transpiration parameters for cheatgrass at the Hanford Site. Improvements in the comparisons between measured and predicted drainage are anticipated with field-measured hydraulic properties and more realistic estimates of grass cover transpiration. However, both measurements and model predictions support the conclusion that under conditions where the majority of the rainfall occurs during periods of low potential evaporation and where soils are coarse textured, significant drainage can occur from the root zone of vegetated areas at Hanford or similar arid zone sites

  14. Inclusion of caraway in the ryegrass-red clover mixture modifies soil microbial community composition

    DEFF Research Database (Denmark)

    Cong, Wenfeng; Jing, Jingying; Søegaard, Karen

    -containing grass-clover mixtures may potentially affect soil microbial community structure, biomass and associated ecosystem functions, but it is yet to be elucidated. We hypothesized that inclusion of plantain in the grass-clover mixture would enhance soil microbial biomas and functions through its high biomass...

  15. Long-term impacts of nitrogen deposition on coastal plant communities

    DEFF Research Database (Denmark)

    Pakeman, Robin J.; Brooker, Rob; Alexander, Jim

    2016-01-01

    , Fixed dune, Heath, Slack and Tall grass mire communities and despite falls in EIV-N for Improved grass, Strand and Wet grassland. The increase in EIV-N was highly correlated to the cumulative deposition between the surveys, and for sites in south-east Scotland, eutrophication impacts appear severe...

  16. Fagopyrum esculentum Alters Its Root Exudation after Amaranthus retroflexus Recognition and Suppresses Weed Growth.

    Science.gov (United States)

    Gfeller, Aurélie; Glauser, Gaétan; Etter, Clément; Signarbieux, Constant; Wirth, Judith

    2018-01-01

    Weed control by crops through growth suppressive root exudates is a promising alternative to herbicides. Buckwheat ( Fagopyrum esculentum ) is known for its weed suppression and redroot pigweed ( Amaranthus retroflexus ) control is probably partly due to allelopathic root exudates. This work studies whether other weeds are also suppressed by buckwheat and if the presence of weeds is necessary to induce growth repression. Buckwheat and different weeds were co-cultivated in soil, separating roots by a mesh allowing to study effects due to diffusion. Buckwheat suppressed growth of pigweed, goosefoot and barnyard grass by 53, 42, and 77% respectively without physical root interactions, probably through allelopathic compounds. Root exudates were obtained from sand cultures of buckwheat (BK), pigweed (P), and a buckwheat/pigweed mixed culture (BK-P). BK-P root exudates inhibited pigweed root growth by 49%. Characterization of root exudates by UHPLC-HRMS and principal component analysis revealed that BK and BK-P had a different metabolic profile suggesting that buckwheat changes its root exudation in the presence of pigweed indicating heterospecific recognition. Among the 15 different markers, which were more abundant in BK-P, tryptophan was identified and four others were tentatively identified. Our findings might contribute to the selection of crops with weed suppressive effects.

  17. Herbivory of an invasive slug is affected by earthworms and the composition of plant communities.

    Science.gov (United States)

    Zaller, Johann G; Parth, Myriam; Szunyogh, Ilona; Semmelrock, Ines; Sochurek, Susanne; Pinheiro, Marcia; Frank, Thomas; Drapela, Thomas

    2013-05-13

    Biodiversity loss and species invasions are among the most important human-induced global changes. Moreover, these two processes are interlinked as ecosystem invasibility is considered to increase with decreasing biodiversity. In temperate grasslands, earthworms serve as important ecosystem engineers making up the majority of soil faunal biomass. Herbivore behaviour has been shown to be affected by earthworms, however it is unclear whether these effects differ with the composition of plant communities. To test this we conducted a mesocosm experiment where we added earthworms (Annelida: Lumbricidae) to planted grassland communities with different plant species composition (3 vs. 12 plant spp.). Plant communities had equal plant densities and ratios of the functional groups grasses, non-leguminous forbs and legumes. Later, Arion vulgaris slugs (formerly known as A. lusitanicus; Gastropoda: Arionidae) were added and allowed to freely choose among the available plant species. This slug species is listed among the 100 worst alien species in Europe. We hypothesized that (i) the food choice of slugs would be altered by earthworms' specific effects on the growth and nutrient content of plant species, (ii) slug herbivory will be less affected by earthworms in plant communities containing more plant species than in those with fewer plant species because of a more readily utilization of plant resources making the impacts of earthworms less pronounced. Slug herbivory was significantly affected by both earthworms and plant species composition. Slugs damaged 60% less leaves when earthworms were present, regardless of the species composition of the plant communities. Percent leaf area consumed by slugs was 40% lower in communities containing 12 plant species; in communities containing only three species earthworms increased slug leaf area consumption. Grasses were generally avoided by slugs. Leaf length and number of tillers was increased in mesocosms containing more plant

  18. How much gas can we get from grass?

    International Nuclear Information System (INIS)

    Nizami, A.S.; Orozco, A.; Groom, E.; Dieterich, B.; Murphy, J.D.

    2012-01-01

    Highlights: ► We highlight the various results for biomethane potential that may be obtained from the same grass silage. ► The results indicated that methane potential varied from 350 to 493 L CH 4 kg −1 VS added for three different BMP procedures. ► We compare two distinct digestion systems using the same grass. ► A two stage wet system achieved 451 L CH 4 kg −1 VS added over a 50 day retention period. ► A two phase system achieved 341 L CH 4 kg −1 VS added at a 30 day retention time. -- Abstract: Grass biomethane has been shown to be a sustainable gaseous transport biofuel, with a good energy balance, and significant potential for economic viability. Of issue for the designer is the variation in characteristics of the grass depending on location of source, time of cut and species. Further confusion arises from the biomethane potential tests (BMP) which have a tendency to give varying results. This paper has dual ambitions. One of these is to highlight the various results for biomethane potential that may be obtained from the same grass silage. The results indicated that methane potential from the same grass silage varied from 350 to 493 L CH 4 kg −1 VS added for three different BMP procedures. The second ambition is to attempt to compare two distinct digestion systems again using the same grass: a two stage continuously stirred tank reactor (CSTR); and a sequentially fed leach bed reactor connected to an upflow anaerobic sludge blanket (SLBR–UASB). The two engineered systems were designed, fabricated, commissioned and operated at small pilot scale until stable optimal operating conditions were reached. The CSTR system achieved 451 L CH 4 kg −1 VS added over a 50 day retention period. The SLBR–UASB achieved 341 L CH 4 kg −1 VS added at a 30 day retention time.

  19. Contrasting patterns of groundwater evapotranspiration in grass and tree dominated riparian zones of a temperate agricultural catchment

    Science.gov (United States)

    Satchithanantham, Sanjayan; Wilson, Henry F.; Glenn, Aaron J.

    2017-06-01

    Consumptive use of shallow groundwater by phreatophytic vegetation is a significant part of the water budget in many regions, particularly in riparian areas. The influence of vegetation type on groundwater level fluctuations and evapotranspiration has rarely been quantified for contrasting plant communities concurrently although it has implications for downstream water yield and quality. Hourly groundwater evapotranspiration (ETG) rates were estimated for grass and tree riparian vegetation in southwestern Manitoba, Canada using two modified White methods. Groundwater table depth was monitored in four 21 m transects of five 3 m deep monitoring wells in the riparian zone of a stream reach including tree (Acer negundo; boxelder) and grass (Bromus inermis; smooth brome) dominated segments. The average depths to the groundwater table from the surface were 1.4 m and 1 m for the tree and grass segments, respectively, over the two-year study. During rain free periods of the growing season ETG was estimated for a total of 70 days in 2014 and 79 days in 2015 when diurnal fluctuations were present in groundwater level. Diurnal groundwater level fluctuations were observed during dry periods under both segments, however, ETG was significantly higher (p < 0.001) under trees compared to grass cover in 2014 (a wet year with 72% higher than normal growing season precipitation) and 2015 (a drier year with 15% higher than normal growing season precipitation). The two methods used to estimate ETG produced similar daily and seasonal values for the two segments. In 2014, total ETG was approximately 50% (148 mm) and 100% (282-285 mm) of reference evapotranspiration (ETref, 281 mm) for the grass and tree segments, respectively. In 2015, total ETG was approximately 40% (106-127 mm) and 120% (369-374 mm) of ETref (307 mm) for the grass and tree segments, respectively. Results from the study show the tree dominated portions of the stream reach consumed approximately 2.4 ML ha-1 yr-1 more

  20. Rooting an Android Device

    Science.gov (United States)

    2015-09-01

    1. Overview The purpose of this document is to demonstrate how to gain administrative privileges on an Android device. The term “rooting” is...is applicable for the Samsung Galaxy S3 as well as many other Android devices, but there are several steps involved in rooting an Android device (as...root access has been granted. 4. Conclusion This document serves as a tutorial on how to grant user administrative privilege to an Android device by