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Sample records for grass species differing

  1. Basalt Weathering, Nutrient Uptake, And Carbon Release By An Exotic And A Native Arizona Grass Species Under Different Temperature Conditions

    NASA Astrophysics Data System (ADS)

    Gallas, G.; Dontsova, K.; Chorover, J.; Hunt, E.; Ravi, S.

    2010-12-01

    During this past summer, the National Science Foundation funded a 10-week Research Experience for Undergraduates (REU) program “Environmental and Earth Systems Research at Biosphere 2”. This program provides undergraduates with an opportunity to conduct guided research in environmental and Earth systems science and has resulted in this work. Biosphere 2 allows for the exploration of complex questions in Earth sciences because of its large scale and the precise control allowed over many experimental elements. The goal of this study was to observe plant-mediated weathering of granular basalt under two temperature conditions. Two grass species were studied, one native to Arizona: Tanglehead, Heteropogan contortus, and one exotic to Arizona: Buffelgrass, Pennisetum ciliar. The grasses were grown in pots located in the Desert and the Savannah Biomes in the Biosphere 2 to take advantage of a 4° C temperature difference. Understanding differences in how native and invasive grasses weather soil and take up nutrients may explain the mechanism behind current invasion of Sonoran Desert by exotic species and help predict response of native and invasive vegetation to expected increase in temperatures. Each biome also contained three replicate “control” pots without vegetation, and mixtures of the two grass species to observe possible competition between the species. Three factors were compared in this study: 1. Temperature: the same species of grass under two different temperature conditions 2. Species: Native Arizonan species vs. a species exotic to Arizona 3. Temporal: How the grasses use resources differently as they grow Leachate samples were collected and analyzed for pH, electrical conductivity, total organic carbon, total nitrogen, inorganic carbon by high temperature combustion coupled with infrared gas analysis; F-, Cl-, Br-, NO3-, NO2-, SO42-, and PO43- by ion chromatography; and cations and metals by ICP-MS. The data trends indicate that plants enhanced

  2. Soil microbial activity under different grass species: Underground impacts of biofuel cropping

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microbial and plant communities interact to determine local nutrient cycling rates. As lands are converted to bioenergy crops, including corn and cellulosic grasses, focus has been on changes in soil carbon sequestration. Little attention has been paid to impacts of such land conversion on the acti...

  3. Phylogenetic divergence morphological and physiological differences distinguish a new neotyphodium endophyte species in the grass bromus auleticus from South America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungi of genus Neotyphodium are systemic, constitutive, symbionts of grasses of subfamily Pooideae. In the southern hemisphere most of these asexual endophytes are the result of the hybridization between two sexual species, Epichloe festucae and E. typhina, from the northern hemisphere. However ...

  4. INTESPECIIC DIFFERENCES IN GRASS SEED IMBIBITION

    EPA Science Inventory

    Seeds from 12 grass species were studied relative to mode of wetting and time of exposure to water to document interspecific differences in imbibition characteristics. Imbibition causes seeds to become wet, and wet seeds are more detectable to consumers than dry seeds. Thus, ge...

  5. Differences in responses to flooding by germinating seeds of two contrasting rice cultivars and two species of economically important grass weeds.

    PubMed

    Estioko, Lucy P; Miro, Berta; Baltazar, Aurora M; Merca, Florinia E; Ismail, Abdelbagi M; Johnson, David E

    2014-01-01

    Crop productivity is largely affected by abiotic factors such as flooding and by biotic factors such as weeds. Although flooding after direct seeding of rice helps suppress weeds, it also can adversely affects germination and growth of rice, resulting in poor crop establishment. Barnyard grasses (Echinochloa spp.) are among the most widespread weeds affecting rice, especially under direct seeding. The present work aimed to establish effective management options to control these weeds. We assessed the effects of variable depths and time of submergence on germination, seedling growth and carbohydrate metabolism of (i) two cultivars of rice known to differ in their tolerance to flooding during germination and (ii) two barnyard grasses (Echinochloa colona and E. crus-galli) that commonly infest rice fields. Flooding barnyard grasses with 100-mm-deep water immediately after seeding was effective in suppressing germination and growth. Echinochloa colona showed greater reductions in emergence, shoot and root growth than E. crus-galli. Delaying flooding for 2 or 4 days was less injurious to both species. Echinochloa colona was also more susceptible to flooding than the flood-sensitive rice cultivar 'IR42'. The activity of alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) in rice seedlings was increased by flooding after sowing but with greater increases in 'Khao Hlan On' compared with 'IR42'. The activity of ADH and PDC was enhanced to a similar extent in both barnyard grasses. Under aerobic conditions, the activity of ADH and PDC in the two barnyard grasses was downregulated, which might contribute to their inherently faster growth compared with rice. Aldehyde dehydrogenase activity was significantly enhanced in flood-tolerant 'Khao Hlan On' and E. crus-galli, but did not increase in flood-sensitive E. colona and 'IR42', implying a greater ability of the flood-tolerant types to detoxify acetaldehyde generated during anaerobic fermentation. Confirmation of this

  6. Exploiting the Potential Differences in Pasture Grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temperate grasses grown for pasture in Wisconsin exhibit a range of chemical and physical characteristics that influence their utilization by grazing cattle. Potential intake of all grasses declines with maturity due to decreasing cell wall digestiblity, but the leaves and stems of orchardgrass and...

  7. Field drying rate differences among three cool-season grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conserving cool-season grasses as silage or hay remains a challenge due to the time required for curing and the unpredictability of weather. We compared the drying rates of three grasses with differing yield potential, morphology, and physical characteristics. Inflorescence-stage meadow fescue, orch...

  8. Long-term persistence of seeded grass species: an unwanted side effect of ecological restoration.

    PubMed

    Rydgren, Knut; Auestad, Inger; Hamre, Liv Norunn; Hagen, Dagmar; Rosef, Line; Skjerdal, Gudrun

    2016-07-01

    Spoil heaps are the visible footprint of hydropower production, particularly in vulnerable alpine environments. Speeding up vegetation development by seeding commercial grass species has been a common restoration practice for the last 50 years, but we lack information on whether seeded species decline and allow native plant cover to develop. We visually estimated cover of native vascular plants and five seeded grass species (Agrostis capillaris, Festuca ovina, Festuca rubra, Schedonorus pratensis and Phleum pratense) on eight spoil heaps at different elevations (boreal-alpine zone) in western Norway. Spoil heap vegetation was censused twice (9-20 and 24-36 years after spoil heap construction); the undisturbed surrounding vegetation was also censused on the second occasion. Total cover on the spoil heaps showed some increase, but remained far below that in surrounding areas. Cover of seeded grass species in the surroundings was low (but not negligible), indicating suboptimal establishment ability. Seeded species usually covered less than 20 % of the spoil heaps, and only F. rubra, F. ovina and A. capillaris contributed substantially. Proportional cover indicated better initial establishment by seeded species, but their cover decreased between the censuses on all but the highest located spoil heap. The persistence of seeded grass species is problematic, and despite the decrease in proportional cover, they are likely to persist for decades on spoil heaps, posing a risk of invasion of surrounding areas. We therefore recommend replacing the practice of seeding with more appropriate restoration measures. PMID:25687605

  9. Contrasting impacts of grass species on nitrogen cycling in a grazed Sudanian savanna

    NASA Astrophysics Data System (ADS)

    Yé, Lambiénou; Abbadie, Luc; Bardoux, Gérard; Lata, Jean-Christophe; Nacro, Hassan Bismarck; Masse, Dominique; de Parseval, Henri; Barot, Sébastien

    2015-02-01

    We investigated the impact of perennial and annuals grass species on nitrogen cycling in a Sudanian savanna of Burkina Faso. We also analysed how the local context in terms of grazing and soil properties modifies these impacts. We selected four plots differing both by the intensity of grazing by cattle and soil depth, and used soil and grass biomass 15N as integrative indicators of N cycle. If perennials are able to foster a more efficient nitrogen cycling there should be lower 15N abundances in their biomass and soil. If soil depth and cattle pressure significantly modify nitrogen fluxes, soil depth and cattle pressure should influence 15N signatures. Our results suggest that perennial grasses are more conservative for nitrogen (inhibition of nitrification, less leaching via a perennial root system, slower cycling). The increase in leaf δ15N with N concentration is steeper in Loudetia togoensis than in the three other grasses. No significant difference was found between the 15N signatures of the four plots. Our results on 15N signatures and the fact that perennial grasses are much more abundant in the plots that are less grazed and have deeper soils, confirm that the switch from perennial to annual grasses is linked to a degradation in soil fertility and pasture quality. This suggests that 15N signatures can be used as indicators of fertility.

  10. Effect of Morphological Traits on Intake Characteristics of Four Grass Species Found in Temperate Biodiverse Pasture Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four grass species (meadow fescue (MF), Festuca pratensis; orchard grass (ORG), Dactylis glomerata, L.; quack grass (QG), Agropyron repens; and reed canary grass (RCG), Phalaris arundinacea) were sown in micro-sward boxes (79 cm x 47 cm x 11.5 cm) to investigate intake characteristics of four grass ...

  11. CO2-caused change in plant species composition rivals the shift in vegetation between mid-grass and tallgrass prairies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atmospheric CO2 enrichment usually changes the contributions of plant species to biomass production of grasslands, but the types of species favored and mechanisms by which change is mediated differ among ecosystems. We measured changes in the contributions of C3 perennial forbs and C4 grasses to abo...

  12. Composition and hydrothermal pretreatment and enzymatic saccharification performance of grasses and legumes from a mixed-species prairie

    PubMed Central

    2011-01-01

    Background Mixtures of prairie species (mixed prairie species; MPS) have been proposed to offer important advantages as a feedstock for sustainable production of fuels and chemicals. Therefore, understanding the performance in hydrothermal pretreatment and enzymatic hydrolysis of select species harvested from a mixed prairie is valuable in selecting these components for such applications. This study examined composition and sugar release from the most abundant components of a plot of MPS: a C3 grass (Poa pratensis), a C4 grass (Schizachyrium scoparium), and a legume (Lupinus perennis). Results from this study provide a platform to evaluate differences between grass and leguminous species, and the factors controlling their recalcitrance to pretreatment and enzymatic hydrolysis. Results Significant differences were found between the grass and leguminous species, and between the individual anatomical components that influence the recalcitrance of MPS. We found that both grasses contained higher levels of sugars than did the legume, and also exhibited higher sugar yields as a percentage of the maximum possible from combined pretreatment and enzymatic hydrolysis. Furthermore, particle size, acid-insoluble residue (AcIR), and xylose removal were not found to have a direct significant effect on glucan digestibility for any of the species tested, whereas anatomical composition was a key factor in both grass and legume recalcitrance, with the stems consistently exhibiting higher recalcitrance than the other anatomical fractions. Conclusions The prairie species tested in this study responded well to hydrothermal pretreatment and enzymatic saccharification. Information from this study supports recommendations as to which plant types and species are more desirable for biological conversion in a mixture of prairie species, in addition to identifying fractions of the plants that would most benefit from genetic modification or targeted growth. PMID:22085451

  13. EFFECT OF MORPHOLOGICAL TRAITS ON INTAKE CHARACTERISTICS OF FOUR GRASS SPECIES FOUND IN TEMPERATE BIODIVERSE PASTURE SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four grass species (meadow fescue (MF), Festuca elatior; orchard grass (ORG), Dactylis glomerata, L.; quack grass (QG), Elytrigia repens; and reed canarygrass (RCG), Phalaris arundinacea) were sown in micro-sward boxes (31 in. x 19 in. x 5 in.) to investigate intake characteristics of four grass spe...

  14. Establishment and growth of experimental grass species mixtures on coal mine sites reclaimed with municipal biosolids

    SciTech Connect

    Halofsky, J.E.; McCormick, L.H.

    2005-05-01

    The Surface Mining Control and Reclamation Act of 1977 requires that coal mine sites in the United States be reclaimed to establish vegetative cover that is diverse, native, and capable of plant succession. However, there is a question as to whether vegetation established on coal mine sites reclaimed with biosolids is diverse and capable of plant succession. The influx of nutrients with the addition of biosolids leads to long-term dominance by early-successional species, most notably grasses, and consequently, a low establishment of woody and volunteer species. Additionally, many grass species commonly planted in reclamation have aggressive growth habits that lead to their dominance in coal mine plant communities. The establishment and growth of selected grass mixes was evaluated to determine whether alternative grass mixes would be less competitive with woody and volunteer species as compared to commonly used grass mixes. Percent vegetative cover, species richness, and the survival of direct-seeded woody species were assessed for each treatment grass mixture. It was found that Poa compress and a mixture of P. compress, Panicum virgatum, and Trifolium repens provided adequate coverage while still allowing the highest species richness and survival of woody species. Use of these species mixtures in coal mine reclamation with biosolids in the eastern United States would likely lead to establishment of a more species-rich plant community with a greater woody species component while still providing erosion control and site protection.

  15. Establishment and growth of experimental grass species mixtures on coal mine sites reclaimed with municipal biosolids.

    PubMed

    Halofsky, Jessica E; McCormick, Larry H

    2005-05-01

    The Surface Mining Control and Reclamation Act of 1977 requires that coal mine sites in the United States be reclaimed to establish vegetative cover that is diverse, native, and capable of plant succession. However, there is a question as to whether vegetation established on coal mine sites reclaimed with biosolids is diverse and capable of plant succession. The influx of nutrients with the addition of biosolids leads to long-term dominance by early-successional species, most notably grasses, and consequently, a low establishment of woody and volunteer species. Additionally, many grass species commonly planted in reclamation have aggressive growth habits that lead to their dominance in coal mine plant communities. The establishment and growth of selected grass mixes was evaluated to determine whether alternative grass mixes would be less competitive with woody and volunteer species as compared to commonly used grass mixes. Percent vegetative cover, species richness, and the survival of direct-seeded woody species were assessed for each treatment grass mixture. It was found that Poa compressa and a mixture of P. compressa, Panicum virgatum, and Trifolium repens provided adequate coverage while still allowing the highest species richness and survival of woody species. Use of these species mixtures in coal mine reclamation with biosolids in the eastern United States would likely lead to establishment of a more species-rich plant community with a greater woody species component while still providing erosion control and site protection. PMID:15920668

  16. Relationships between functional traits and inorganic nitrogen acquisition among eight contrasting European grass species

    PubMed Central

    Grassein, Fabrice; Lemauviel-Lavenant, Servane; Lavorel, Sandra; Bahn, Michael; Bardgett, Richard D.; Desclos-Theveniau, Marie; Laîné, Philippe

    2015-01-01

    Backgrounds and Aims Leaf functional traits have been used as a basis to categoize plants across a range of resource-use specialization, from those that conserve available resources to those that exploit them. However, the extent to which the leaf functional traits used to define the resource-use strategies are related to root traits and are good indicators of the ability of the roots to take up nitrogen (N) are poorly known. This is an important question because interspecific differences in N uptake have been proposed as one mechanism by which species’ coexistence may be determined. This study therefore investigated the relationships between functional traits and N uptake ability for grass species across a range of conservative to exploitative resource-use strategies. Methods Root uptake of NH4+ and NO3–, and leaf and root functional traits were measured for eight grass species sampled at three grassland sites across Europe, in France, Austria and the UK. Species were grown in hydroponics to determine functional traits and kinetic uptake parameters (Imax and Km) under standardized conditions. Key Results Species with high specific leaf area (SLA) and shoot N content, and low leaf and root dry matter content (LDMC and RDMC, respectively), which are traits associated with the exploitative syndrome, had higher uptake and affinity for both N forms. No trade-off was observed in uptake between the two forms of N, and all species expressed a higher preference for NH4+. Conclusions The results support the use of leaf traits, and especially SLA and LDMC, as indicators of the N uptake ability across a broad range of grass species. The difficulties associated with assessing root properties are also highlighted, as root traits were only weakly correlated with leaf traits, and only RDMC and, to a lesser extent, root N content were related to leaf traits. PMID:25471096

  17. Abiotic stresses activate a MAPkinase in the model grass species Lolium temulentum L.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage and turf grasses are utilized in diverse environments which exposes them to a variety of abiotic stresses, however very little is known concerning the perception or molecular responses to these various stresses. In the model grass species Lolium temulentum (Lt), a 46 kDa mitogen-activated pro...

  18. Assessing impacts of introduced aquatic species: Grass carp in large systems

    NASA Astrophysics Data System (ADS)

    Bain, Mark B.

    1993-03-01

    Introduced species have created environmental benefits and unanticipated disasters so a priori assessments of species introductions are needed for environmental management. A checklist for assessing impacts of introduced species was developed from studies of introduced species and recommendations for planning introductions. Sterile, triploid grass carp ( Ctenopharyngodon idella) are just beginning to be used as a biocontrol agent for the management of aquatic vegetation in open waterways. Potential impacts of grass carp in open systems were identified by reviewing grass carp biology relative to the impact assessment checklist. The potential consequences of introduced grass carp were reviewed for one case study. The case study demonstrated that conclusions about potential impacts and monitoring needs can be made despite incomplete information and uncertainty. Indicators of environmental impact and vulnerability of host systems were grouped into six categories: population control, hybridization, diseases and parasites, habitat alterations, biological effects, and management issues. Triploid grass carp can significantly alter habitat and biological resources through the secondary effects of reductions in aquatic vegetation. Potential impacts and significant uncertainties involve fish dispersions from plant control areas, inability to control vegetation loss, loss of diverse plant communities and their dependent species, and conflicts with human use of the water resource. Adequate knowledge existed to assess most potential consequences of releasing large numbers of triploid grass carp in Guntersville Reservoir, Alabama. However, the assessment of potential impacts indicated that moderate, incremental stockings combined with monitoring of vegetation and biological resources are necessary to control the effects of grass carp and achieve desirable, intermediate plant densities.

  19. Fire Intensity and its Effects on Four Major Grass Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fuel and fire conditions needed to cause grass mortality are largely unknown. Individual plants of Hesperostipa comata, Carex filifolia, Bouteloua gracilis, and Pascopyrum smithii were collected from rangeland, potted, and acclimated to greenhouse conditions. Plants were exposed to fire in 1-by-0...

  20. Divergent Evolutionary Pattern of Sugar Transporter Genes is Associated with the Difference in Sugar Accumulation between Grasses and Eudicots.

    PubMed

    Wang, Wei; Zhou, Hui; Ma, Baiquan; Owiti, Albert; Korban, Schuyler S; Han, Yuepeng

    2016-01-01

    Sugars play a variety of roles in plants, and their accumulation in seeds and/or surrounding pericarp tissues is distinctly different between grasses and eudicots. However, little is known about the evolutionary pattern of genes involved in sugar accumulation in these two major groups of flowering plants. Here, we compared evolutionary rates, gene duplication, and selective patterns of genes involved in sugar metabolism and transport between grasses and eudicots using six grass species and seven eudicot species as materials. Overall, sugar transporter genes exhibit divergent evolutionary patterns, whereas, sugar metabolism genes showing similar evolutionary pattern between monocots and eudicots. Sugar transporter genes have higher frequencies of recent duplication in eudicots than in grasses and their patterns of evolutionary rate are different. Evidence for divergent selection of these two groups of flowering plants is also observed in sugar transporter genes, wherein, these genes have undergone positive selection in eudicots, but not in grasses. Taken together, these findings suggest that sugar transporter genes rather than sugar metabolism genes play important roles in sugar accumulation in plants, and that divergent evolutionary patterns of sugar transporter genes are associated with the difference of sugar accumulation in storage tissues of grasses and eudicots. PMID:27356489

  1. Divergent Evolutionary Pattern of Sugar Transporter Genes is Associated with the Difference in Sugar Accumulation between Grasses and Eudicots

    PubMed Central

    Wang, Wei; Zhou, Hui; Ma, Baiquan; Owiti, Albert; Korban, Schuyler S.; Han, Yuepeng

    2016-01-01

    Sugars play a variety of roles in plants, and their accumulation in seeds and/or surrounding pericarp tissues is distinctly different between grasses and eudicots. However, little is known about the evolutionary pattern of genes involved in sugar accumulation in these two major groups of flowering plants. Here, we compared evolutionary rates, gene duplication, and selective patterns of genes involved in sugar metabolism and transport between grasses and eudicots using six grass species and seven eudicot species as materials. Overall, sugar transporter genes exhibit divergent evolutionary patterns, whereas, sugar metabolism genes showing similar evolutionary pattern between monocots and eudicots. Sugar transporter genes have higher frequencies of recent duplication in eudicots than in grasses and their patterns of evolutionary rate are different. Evidence for divergent selection of these two groups of flowering plants is also observed in sugar transporter genes, wherein, these genes have undergone positive selection in eudicots, but not in grasses. Taken together, these findings suggest that sugar transporter genes rather than sugar metabolism genes play important roles in sugar accumulation in plants, and that divergent evolutionary patterns of sugar transporter genes are associated with the difference of sugar accumulation in storage tissues of grasses and eudicots. PMID:27356489

  2. Evaluating indigenous grass species as on-site sediment trapping measures, northwest Ethiopian highlands

    NASA Astrophysics Data System (ADS)

    Mekonnen, Mulatie; Keesstra, Saskia; Ritsema, Coen; Stroosnijder, Leo; Baartman, Jantiene

    2016-04-01

    Although many studies have been conducted to evaluate the sediment trapping efficacy (STE) of grass species as an on-site sediment trapping measure, still a lot of grass species are availab1e of which their STE is unknown. Lack of information on the STE of such grass species has a negative influence on their acceptance and practical application by the users. Therefore, this study was conducted at Debre Mewi watershed, northwestern Ethiopian highlands, to evaluate the STE of four locally dominant indigenous grass species (Desho, Senbelet, Akirma and Sebez) and one exotic species (Vetiver) using plot experiments. On average, the annual runoff produced was found to be 79; 64; 69; 71; 74; 75 l m-2, which resulted in 7; 1.7; 2.9; 3.6; 4.5 and 5.6 kg m-2 yr-1 of sediment yield on the Control, Desho, Vetiver, Senbelet, Akirma and Sebez plots, respectively. Desho had a trapping efficacy of 76 % because of its fast growth and lateral spreading nature. Vetiver and Senbelet reduced the transported sediment with 59 % and 49 % STE, respectively. Because of their slow growth nature, Akirma and Sebez showed low STEs, 36 % and 20 %, respectively. The grass species were found to be important sources of livestock feed in addition to trapping sediment and reducing soil loss. Desho, Senbelet, Akirma, Vetiver and Sebez provided 132, 106, 76, 69 and 51 t ha-1 yr-1 fresh biomass, respectively. The indigenous grass species provided a practical means to reduce sediment yield, therefore, it can be concluded that such indigenous grass species can be used as an on-site sediment trapping measure in the northwestern highlands of Ethiopia.

  3. Are High-Impact Species Predictable? An Analysis of Naturalised Grasses in Northern Australia

    PubMed Central

    van Klinken, Rieks D.; Panetta, F. Dane; Coutts, Shaun R.

    2013-01-01

    Predicting which species are likely to cause serious impacts in the future is crucial for targeting management efforts, but the characteristics of such species remain largely unconfirmed. We use data and expert opinion on tropical and subtropical grasses naturalised in Australia since European settlement to identify naturalised and high-impact species and subsequently to test whether high-impact species are predictable. High-impact species for the three main affected sectors (environment, pastoral and agriculture) were determined by assessing evidence against pre-defined criteria. Twenty-one of the 155 naturalised species (14%) were classified as high-impact, including four that affected more than one sector. High-impact species were more likely to have faster spread rates (regions invaded per decade) and to be semi-aquatic. Spread rate was best explained by whether species had been actively spread (as pasture), and time since naturalisation, but may not be explanatory as it was tightly correlated with range size and incidence rate. Giving more weight to minimising the chance of overlooking high-impact species, a priority for biosecurity, meant a wider range of predictors was required to identify high-impact species, and the predictive power of the models was reduced. By-sector analysis of predictors of high impact species was limited by their relative rarity, but showed sector differences, including to the universal predictors (spread rate and habitat) and life history. Furthermore, species causing high impact to agriculture have changed in the past 10 years with changes in farming practice, highlighting the importance of context in determining impact. A rationale for invasion ecology is to improve the prediction and response to future threats. Although our study identifies some universal predictors, it suggests improved prediction will require a far greater emphasis on impact rather than invasiveness, and will need to account for the individual circumstances of

  4. Discriminating indicator grass species for rangeland degradation assessment using hyperspectral data resampled to AISA Eagle resolution

    NASA Astrophysics Data System (ADS)

    Mansour, Khalid; Mutanga, Onisimo; Everson, Terry; Adam, Elhadi

    2012-06-01

    The development of techniques to estimate and map increaser grass species is critical for better understanding the condition of the rangeland and levels of rangeland degradation. This paper investigates whether canopy reflectance spectra, resampled to AISA Eagle resolution can discriminate among four increaser species representing different levels of rangeland degradation. Canopy spectral measurements were taken from the four indicator species: Hyparrhenia hirta (HH), Eragrostis curvula (EC), Sporobolus africanus (SA), and Aristida diffusa (AD). The random forest algorithm and a forward variable selection technique were used to identify optimal wavelengths for discriminating the species. Results revealed that the optimal number of wavelengths (n = 8) that yielded the lowest OOB error (11.36%) in discriminating among the four increaser species are located in 966.7, 877.6, 691.9, 718.7, 902.7, 854.8, 674.1 and 703 nm. These wavelengths are located in the visible, red-edge and near-infrared regions of the electromagnetic spectrum. The random forest algorithm can accurately discriminate species with an overall accuracy of 88.64% and a KHAT value of 0.85. The study demonstrated the possibility to upscale the method to airborne sensors such as AISA Eagle for mapping indicator species of rangeland degradation. A rotational grazing management plan should be considered as a way to create sustainable rangeland management in degraded areas.

  5. THE HEALING HAND OF TIME: NATIVE SPECIES REPLACE INTRODUCED GRASS CULTIVARS SEEDED FOLLOWING WILDFIRE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seeding of non-native species following wildfires to prevent erosion has become a controversial practice for several reasons: it risks inhibiting tree regeneration, introducing noxious weeds, and permanently replacing native species. The paper reports the fate of non-native seeded grasses 31 years ...

  6. Habitat-specific differences in plasticity of foliar δ13C in temperate steppe grasses

    PubMed Central

    Liu, Yanjie; Zhang, Lirong; Niu, Haishan; Sun, Yue; Xu, Xingliang

    2014-01-01

    A decrease in foliar δ13C with increasing precipitation is a common tendency in steppe plants. However, the rate of decrease has been reported to differ between different species or populations. We here hypothesized that plant populations in the same habitat of temperate steppes may not differ in foliar δ13C response patterns to precipitation, but could differ in the levels of plasticity of foliar δ13C across different habitats. In order to test this hypothesis, we conducted controlled watering experiments in northeast China at five sites along a west–east transect at latitude 44°N, which show substantial interannual fluctuations and intra-annual changes in precipitation among them. In 2001, watering treatment (six levels, three replicates) was assigned to 18 plots at each site. The responses of foliar δ13C to precipitation (i.e., the sum of watering and rainfall) were determined in populations of several grass species that were common across all sites. Although similar linear regression slopes were observed for populations of different species growing at the same site, significantly different slopes were obtained for populations of the same species growing at different sites. Further, the slope of the line progressively decreased from Site I to Site V for all species in this study. These results suggest habitat-specific differences in plasticity of foliar δ13C in temperate steppe grasses. This indicates that species' δ13C response to precipitation is conservative at the same site due to their long-term acclimation, but the mechanism responsible behind this needs further investigations. PMID:25035804

  7. Endophytic Epichloë species and their grass hosts: from evolution to applications.

    PubMed

    Saikkonen, Kari; Young, Carolyn A; Helander, Marjo; Schardl, Christopher L

    2016-04-01

    The closely linked fitness of the Epichloë symbiont and the host grass is presumed to align the coevolution of the species towards specialization and mutually beneficial cooperation. Ecological observations demonstrating that Epichloë-grass symbioses can modulate grassland ecosystems via both above- and belowground ecosystem processes support this. In many cases the detected ecological importance of Epichloë species is directly or indirectly linked to defensive mutualism attributable to alkaloids of fungal-origin. Now, modern genetic and molecular techniques enable the precise studies on evolutionary origin of endophytic Epichloë species, their coevolution with host grasses and identification the genetic variation that explains phenotypic diversity in ecologically relevant characteristics of Epichloë-grass associations. Here we briefly review the most recent findings in these areas of research using the present knowledge of the genetic variation that explains the biosynthetic pathways driving the diversity of alkaloids produced by the endophyte. These findings underscore the importance of genetic interplay between the fungus and the host in shaping their coevolution and ecological role in both natural grass ecosystems, and in the agricultural arena. PMID:26542393

  8. Native species replace introduced grass cultivars seeded following wildfire

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seeding of non-native species following wildfires to stabilize soils and prevent erosion has become a controversial practice because it risks inhibiting tree regeneration, introducing noxious weeds, and permanently replacing native species. This paper reports the fate of non-native seeded species du...

  9. Effects of grass species and grass growth on atmospheric nitrogen deposition to a bog ecosystem surrounded by intensive agricultural land use

    PubMed Central

    Hurkuck, Miriam; Brümmer, Christian; Mohr, Karsten; Spott, Oliver; Well, Reinhard; Flessa, Heinz; Kutsch, Werner L

    2015-01-01

    We applied a 15N dilution technique called “Integrated Total Nitrogen Input” (ITNI) to quantify annual atmospheric N input into a peatland surrounded by intensive agricultural practices over a 2-year period. Grass species and grass growth effects on atmospheric N deposition were investigated using Lolium multiflorum and Eriophorum vaginatum and different levels of added N resulting in increased biomass production. Plant biomass production was positively correlated with atmospheric N uptake (up to 102.7 mg N pot−1) when using Lolium multiflorum. In contrast, atmospheric N deposition to Eriophorum vaginatum did not show a clear dependency to produced biomass and ranged from 81.9 to 138.2 mg N pot−1. Both species revealed a relationship between atmospheric N input and total biomass N contents. Airborne N deposition varied from about 24 to 55 kg N ha−1 yr−1. Partitioning of airborne N within the monitor system differed such that most of the deposited N was found in roots of Eriophorum vaginatum while the highest share was allocated in aboveground biomass of Lolium multiflorum. Compared to other approaches determining atmospheric N deposition, ITNI showed highest airborne N input and an up to fivefold exceedance of the ecosystem-specific critical load of 5–10 kg N ha−1 yr−1. PMID:26257870

  10. Relationships among non-Acremonium sp. fungal endophytes in five grass species.

    PubMed Central

    An, Z Q; Siegel, M R; Hollin, W; Tsai, H F; Schmidt, D; Schardl, C L

    1993-01-01

    Many cool-season grasses (subfamily Pooideae) possess maternally transmitted fungal symbionts which cause no known pathology and often enhance the ecological fitness and biochemical capabilities of the grass hosts. The most commonly described endophytes are the Acremonium section Albo-lanosa spp. (Acremonium endophytes), which are conidial anamorphs (strictly asexual forms) of Epichloë typhina. Other endophytes which have been noted are a Gliocladium-like fungus in perennial ryegrass (Lolium perenne L.) and a Phialophora-like fungus in tall fescue (Festuca arundinacea Schreb.). Here, we report the identification of additional non-Acremonium sp. endophytes (herein designated p-endophytes) in three more grass species: Festuca gigantea, Festuca arizonica, and Festuca pratensis. In each grass species, the p-endophyte was cosymbiotic with an Acremonium endophyte. Serological analysis and sequence determinations of variable portions of their rRNA genes indicated that the two previously identified non-Acremonium endophytes are closely related to each other and to the newly identified p-endophytes. Therefore, the p-endophytes represent a second group of widely distributed grass symbionts. Images PMID:8517749

  11. Measurement of key compositional parameters in two species of energy grass by Fourier transform infrared spectroscopy.

    PubMed

    Allison, Gordon G; Morris, Catherine; Hodgson, Edward; Jones, Jenny; Kubacki, Michal; Barraclough, Tim; Yates, Nicola; Shield, Ian; Bridgwater, Anthony V; Donnison, Iain S

    2009-12-01

    Two energy grass species, switch grass, a North American tuft grass, and reed canary grass, a European native, are likely to be important sources of biomass in Western Europe for the production of biorenewable energy. Matching chemical composition to conversion efficiency is a primary goal for improvement programmes and for determining the quality of biomass feed-stocks prior to use and there is a need for methods which allow cost effective characterisation of chemical composition at high rates of sample through-put. In this paper we demonstrate that nitrogen content and alkali index, parameters greatly influencing thermal conversion efficiency, can be accurately predicted in dried samples of these species grown under a range of agronomic conditions by partial least square regression of Fourier transform infrared spectra (R(2) values for plots of predicted vs. measured values of 0.938 and 0.937, respectively). We also discuss the prediction of carbon and ash content in these samples and the application of infrared based predictive methods for the breeding improvement of energy grasses. PMID:19660936

  12. MT and WY Tamarix soil properties influence germination and early growth of three native grass species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As a riparian invader, Tamarix spp. often leads to native species (e.g., plains cottonwood and willows, grasses) decline and lower habitat quality. Since Tamarix excretes excess salt and has high salt tolerance, negative soil feedback via high soil salinity may negatively affect native plants. Howev...

  13. Three new species of eriophyoid mites from grass hosts in Croatia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three new species of grass-feeding eriophyid mites are described from Croatia: Acaralox croatiae n. sp., inhabiting purple moorgrass, Molinia coerulea (L.) Moench; Aculodes festucae n. sp., inhabiting tall fescue, Festuca arundinacea Schreb.; and Aculodes sylvatici n. sp., inhabiting false brome, Br...

  14. Intake characteristics of grass species from semi-natural pastures in the United Kingdom

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four grass species (Lolium perenne L., Holcus lanatus L. cv Glen, Agrostis stolonifera L. cv Kromi, and Poa trivialis L.) commonly found in mesotropic lowland semi-natural grassland communities in the UK were sown in boxes (85 x 44 x 14 cm) to create micro-swards. Once established, the micro-sward...

  15. Selenium accumulation and selenium-salt co-tolerance in five grass species. [Festuca arundinaceae; Agropyron deserorum; Buchloe dactyloides; Agrostis stolonifera; Cynodon dactylon

    SciTech Connect

    Wu, L.; Huang, Z.; Burau, R.G.

    1987-04-01

    Five grass species including Tall fescue (Festuca arundinaceae Schred), Crested wheatgrass (Agropyron deserorum Fisch), Buffalo grass (Buchlor dactyloides (Nutt.) Engelm.), Seaside bentgrass (Agrostis stolonifera L.) and Bermuda grass (Cynodon dactylon (L.) Pers., Syn.) were examined for selenium and salt tolerance and selenium accumulation under solution culture conditions. Distinct differences in both selenium and salt tolerance were detected among the five species, but no direct association between selenium and salt resistance was found. Tall fescue displayed considerable tolerance under 1 ppm selenium and 100 mM salt treatment. Combined selenium and salt treatment revealed that selenium uptake was increased by the incorporation of salt in the culture solution. However, salt uptake was not significantly affected by the presence of selenium in the culture solution. At moderate toxic levels of selenium, the species with greater tolerance accumulated less selenium than did the less tolerant species.

  16. Species introductions and the phylogenetic and functional structure of California's grasses.

    PubMed

    Sandel, Brody; Tsirogiannis, Constantinos

    2016-02-01

    Many species assemblages represent a nonrandom subset of a larger species pool. When an assemblage tends to contain close evolutionary relatives or species with similar functional traits, it can be described as phylogenetically or functionally clustered. Clustering is often interpreted as evidence for filtering by some combination of environmental and biotic factors. At sufficiently large spatial extents, however, biogeographic barriers can also lead to strong clustering. Here, we suggest that the breakdown of biogeographic barriers associated with human introductions of exotic species can be used as an unintentional experiment to assess their importance in driving phylogenetic and functional structure. An important role of biogeographic barriers would be revealed by a breakdown in clustering, particularly phylogenetic clustering, following species introductions. On the other hand, a role of filtering can be supported by similar patterns of clustering in the native and exotic assemblages along environmental gradients. We test these predictions using the grasses of California, a diverse group including many introduced species. Native grass assemblages in the state are highly clustered with respect to the global grass species pool, both phylogenetically and functionally. Within the state, variation in the strength of clustering is well explained by climatic variables, suggesting an important role for environmental-biotic filtering. Further, subregions within the state with highly clustered native assemblages also contain highly clustered exotic assemblages. Contrary to expectation, though, the introduction of exotic species led to even more strongly clustered assemblages. We conclude that biogeographic barriers have generally not excluded the major grass lineages (e.g., tribes) from the state and likely act only on finer taxonomic scales (for example, excluding particular genera). Our approach should prove broadly applicable and contribute to improved understanding

  17. Differences in grass pollen allergen exposure across Australia

    PubMed Central

    Beggs, Paul J.; Katelaris, Constance H.; Medek, Danielle; Johnston, Fay H.; Burton, Pamela K.; Campbell, Bradley; Jaggard, Alison K.; Vicendese, Don; Bowman, David M.J.S.; Godwin, Ian; Huete, Alfredo R.; Erbas, Bircan; Green, Brett J.; Newnham, Rewi M.; Newbigin, Ed; Haberle, Simon G.; Davies, Janet M.

    2015-01-01

    Objective Allergic rhinitis and allergic asthma are important chronic diseases posing serious public health issues in Australia with associated medical, economic, and societal burdens. Pollen are significant sources of clinically relevant outdoor aeroallergens, recognised as both a major trigger for, and cause of, allergic respiratory diseases. This study aimed to provide a national, and indeed international, perspective on the state of Australian pollen data using a large representative sample. Methods Atmospheric grass pollen concentration is examined over a number of years within the period 1995 to 2013 for Brisbane, Canberra, Darwin, Hobart, Melbourne, and Sydney, including determination of the ‘clinical’ grass pollen season and grass pollen peak. Results The results of this study describe, for the first time, a striking spatial and temporal variability in grass pollen seasons in Australia, with important implications for clinicians and public health professionals, and the Australian grass pollen-allergic community. Conclusions These results demonstrate that static pollen calendars are of limited utility and in some cases misleading. This study also highlights significant deficiencies and limitations in the existing Australian pollen monitoring and data. Implications Establishment of an Australian national pollen monitoring network would help facilitate advances in the clinical and public health management of the millions of Australians with asthma and allergic rhinitis. PMID:25648730

  18. Field drying rate differences amoung cool-season grasses harvested for hay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Making high-quality, cool-season grass hay is a challenge, due to the field drying time needed to reach the appropriate moisture content and the high probability of rain in the spring when hay is typically produced. This study was conducted to determine if cool-season grasses with different yield po...

  19. Interactive effects of plant-available soil silicon and herbivory on competition between two grass species

    PubMed Central

    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

  20. Defending the leaf surface: intra- and inter-specific differences in silicon deposition in grasses in response to damage and silicon supply

    PubMed Central

    Hartley, Sue E.; Fitt, Rob N.; McLarnon, Emma L.; Wade, Ruth N.

    2015-01-01

    Understanding interactions between grasses and their herbivores is central to the conservation of species-rich grasslands and the protection of our most important crops against pests. Grasses employ a range of defenses against their natural enemies; silicon-based defenses have been shown to be one of the most effective. Silicon (Si) is laid down on the leaf surface as spines and other sharp bodies, known as phytoliths, making grasses abrasive and their foliage indigestible to herbivores. Previous studies on Si defenses found that closely related species may have similar levels of Si in the leaves but differ markedly in abrasiveness. Here we show how the number, shape and distribution of Si-rich phytoliths and spines differ within and between different grass species and demonstrate that species also differ in their ability to change the deposition and distribution of these defenses in response to damage or increases in Si supply. Specifically, we tested the response of two genotypes of Festuca arundinacea known to differ in their surface texture and three different grass species (F. ovina, F. rubra, and Deschampsia cespitosa) differing in their abrasiveness to combined manipulation of leaf damage and Si supply. F. arundinacea plants with a harsh leaf surface had higher Si content and more spines on their leaf surface than soft varieties. F. ovina and D. cespitosa plants increased their leaf Si concentration and produced an increase in the number of leaf spines and phytoliths on the leaf surface in response to Si addition. F rubra also increased leaf Si content in response to treatments, particularly in damaged leaves, but did not deposit this in the form of spines or increased densities of phytoliths. We discuss how the form in which grasses deposit Si may affect their anti-herbivore characteristics and consider the ecological and agricultural implications of the differences in allocation to Si-based defenses between grass species. PMID:25717331

  1. Control of one invasive plant species allows exotic grasses to become dominant in northern Great Plains grasslands

    USGS Publications Warehouse

    Larson, D.L.; Larson, J.L.

    2010-01-01

    Decline of leafy spurge (Euphorbia esula) in the northern Great Plains of the US is generally viewed as a success story for biological control, but quality of the vegetation that survived the infestation is key to recovery of ecosystem function. In addition, effects of other invasive species, notably cool-season exotic grasses, must be taken into account. Objectives of this study were (1) to evaluate direction and significance of changes in biomass of native and exotic grasses, forbs, and leafy spurge and in plant species composition following control of leafy spurge by flea beetles and (2) to evaluate the relative effects of leafy spurge and exotic grasses on biomass of native grasses, biomass of forbs, and richness of native species. We monitored species composition (1998-2003 and 2008) and biomass (2000, 2002, 2003 and 2008) of these groups on spurge-infested and noninfested permanent plots at three sites with unbroken prairie sod in North Dakota, USA. We found little evidence, in terms of species richness or biomass of native grasses or forbs, that leafy spurge was being replaced by desirable native species, although desirable as well as weedy and exotic species were characteristic of 2008 vegetation at all three sites. Structural equation models revealed that leafy spurge had temporally intermittent negative effects on forb biomass and species richness, but no effects on native grasses. In contrast, exotic grass had consistently strong, negative effects on native grass biomass, as well as stronger negative effects than leafy spurge on native species richness. Although substantial native plant diversity remains at these sites, exotic grasses pose an important threat to these crucial building blocks of native prairie ecosystems. ?? 2010.

  2. Four new species in Magnaporthaceae from grass roots in New Jersey Pine Barrens.

    PubMed

    Luo, Jing; Walsh, Emily; Zhang, Ning

    2014-01-01

    Based on morphology and DNA sequences of SSU, ITS, LSU, MCM7, RPB1 and TEF1 genes, we describe four new species in Magnaporthaceae that are associated with grass roots collected from New Jersey Pine Barrens. A new genus, Pseudophialophora, is erected to accommodate three species, which is characterized by slow growth on potato dextrose agar, curved conidiogenous cells without a conspicuous collarette at the apex and oblong ellipsoidal conidia. Pseudophialophora eragrostis, P. panicorum and P. schizachyrii are assigned to this genus. A new species of Magnaporthiopsis also is reported and named as M. panicorum. Distinctions between them and phylogenetic relationships with other Magnaporthaceae taxa are discussed. PMID:24871590

  3. Five new Pseudophialophora species from grass roots in the oligotrophic pine barrens ecosystem.

    PubMed

    Luo, Jing; Walsh, Emily; Blystone, David; Zhang, Ning

    2015-12-01

    During our recent survey of fungi in the oligotrophic pine barrens ecosystem, five new Pseudophialophora species, Pseudophialophora angusta, P. dichanthii, P. magnispora, P. tarda, and P. whartonensis, were uncovered from the roots of switchgrass (Panicum virgatum) and tapered rosette grass (Dichanthelium acuminatum). The five new fungal species are described based on morphological characteristics and DNA sequences of SSU, ITS, LSU, MCM7, RPB1, and TEF1 genes. The 6-locus phylogeny indicates that Pseudophialophora species form a monophyletic clade in Magnaporthaceae of Magnaporthales. A key for all described species in Pseudophialophora is provided, including these five and three previously published species. Distinctions among the new species and other related species are discussed. The plant-fungal interaction experiment indicates that P. angusta, Pseudophialophora eragrostis, P. magnispora, Pseudophialophora schzachyrii, P. tarda, and P. whartonensis have negative effects on the growth of switchgrass. Runner hyphae were observed from the inoculated switchgrass roots, which are typical structures of root-infecting pathogens. PMID:26615743

  4. Links between Genetic Groups, Indole Alkaloid Profiles and Ecology within the Grass-Parasitic Claviceps purpurea Species Complex

    PubMed Central

    Negård, Mariell; Uhlig, Silvio; Kauserud, Håvard; Andersen, Tom; Høiland, Klaus; Vrålstad, Trude

    2015-01-01

    The grass parasitic fungus Claviceps purpurea sensu lato produces sclerotia with toxic indole alkaloids. It constitutes several genetic groups with divergent habitat preferences that recently were delimited into separate proposed species. We aimed to 1) analyze genetic variation of C. purpurea sensu lato in Norway, 2) characterize the associated indole alkaloid profiles, and 3) explore relationships between genetics, alkaloid chemistry and ecology. Approximately 600 sclerotia from 14 different grass species were subjected to various analyses including DNA sequencing and HPLC-MS. Molecular results, supported by chemical and ecological data, revealed one new genetic group (G4) in addition to two of the three known; G1 (C. purpurea sensu stricto) and G2 (C. humidiphila). G3 (C. spartinae) was not found. G4, which was apparently con-specific with the recently described C. arundinis sp. nov, was predominantly found in very wet habitats on Molinia caerulea and infrequently in saline habitats on Leymus arenarius. Its indole-diterpene profile resembled G2, while its ergot alkaloid profile differed from G2 in high amounts of ergosedmam. In contrast to G1, indole-diterpenes were consistently present in G2 and G4. Our study supports and complements the newly proposed species delimitation of the C. purpurea complex, but challenges some species characteristics including host spectrum, habitat preferences and sclerotial floating ability. PMID:25928134

  5. Links between Genetic Groups, Indole Alkaloid Profiles and Ecology within the Grass-Parasitic Claviceps purpurea Species Complex.

    PubMed

    Negård, Mariell; Uhlig, Silvio; Kauserud, Håvard; Andersen, Tom; Høiland, Klaus; Vrålstad, Trude

    2015-05-01

    The grass parasitic fungus Claviceps purpurea sensu lato produces sclerotia with toxic indole alkaloids. It constitutes several genetic groups with divergent habitat preferences that recently were delimited into separate proposed species. We aimed to 1) analyze genetic variation of C. purpurea sensu lato in Norway, 2) characterize the associated indole alkaloid profiles, and 3) explore relationships between genetics, alkaloid chemistry and ecology. Approximately 600 sclerotia from 14 different grass species were subjected to various analyses including DNA sequencing and HPLC-MS. Molecular results, supported by chemical and ecological data, revealed one new genetic group (G4) in addition to two of the three known; G1 (C. purpurea sensu stricto) and G2 (C. humidiphila). G3 (C. spartinae) was not found. G4, which was apparently con-specific with the recently described C. arundinis sp. nov, was predominantly found in very wet habitats on Molinia caerulea and infrequently in saline habitats on Leymus arenarius. Its indole-diterpene profile resembled G2, while its ergot alkaloid profile differed from G2 in high amounts of ergosedmam. In contrast to G1, indole-diterpenes were consistently present in G2 and G4. Our study supports and complements the newly proposed species delimitation of the C. purpurea complex, but challenges some species characteristics including host spectrum, habitat preferences and sclerotial floating ability. PMID:25928134

  6. Green leaf volatiles, fire and nonanoic acid activate MAPkinases in the model grass species Lolium temulentum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage and turf related grasses are utilized in diverse environments where they are routinely subjected to herbicides and exposed to fire and volatiles after cutting, however very little is known concerning the perception or molecular responses to these different stresses or compounds. In the model ...

  7. Efficacy of Biosolids in Assisted Phytostabilization of Metalliferous Acidic Sandy Soils with Five Grass Species

    PubMed Central

    Kacprzak, Malgorzata; Grobelak, Anna; Grosser, Anna; Prasad, M. N. V.

    2013-01-01

    The role of sewage sludge as an immobilising agent in the phytostabilization of metal-contaminated soil was evaluated using five grass species viz., Dactylis glomerata L., Festuca arundinacea Schreb., F. rubra L., Lolium perenne L., L. westerwoldicum L. The function of metal immobilization was investigated by monitoring pH, Eh and Cd, Pb, and Zn levels in column experiment over a period of 5-months. Grasses grown on sewage sludge-amendments produced high biomass in comparison to controls. A significant reduction in metal uptake by plants was also observed as a result of sewage sludge application, which was attributed to decreased bioavailability through soil stabilisation. We have observed that the sludge amendment decreased metal bioavailability and concentrations in soil at a depth of 25 cm, in contrast to untreated columns, where metal concentrations in the soil solution were very high. PMID:24912245

  8. Distribution of infective gastrointestinal helminth larvae in tropical erect grass under different feeding systems for lambs.

    PubMed

    Tontini, Jalise Fabíola; Poli, Cesar Henrique Espírito Candal; Bremm, Carolina; de Castro, Juliane Machado; Fajardo, Neuza Maria; Sarout, Bruna Nunes Marsiglio; Castilhos, Zélia Maria de Souza

    2015-08-01

    This study examined tropical pasture contamination dynamics under different feeding systems for finishing lambs. The experiment aimed to evaluate the vertical distribution of gastrointestinal helminth infective larvae (L3) in erect grass subjected to grazing and to assess the parasite load and its impact on lamb performance in three production systems. Three treatments based on Aruana grass (Panicum maximum cv. IZ-5) were as follows: T1, grass only; T2, grass with 1.5% of body weight (BW) nutrient concentrate supplementation; and T3, grass with 2.5% BW concentrate supplementation. The randomized block design had three replicates of three treatments, with six lambs per replicate. L3 were recovered from three pasture strata (upper, middle, and bottom), each representing one third of the sward height, and correlated with microclimatic data. Significant differences (P < 0.05) were observed among treatments in the L3 recovery. Despite different grass heights between treatments and microclimates within the sward, the L3 concentration generally did not differ significantly among the three strata within a treatment (P > 0.05). Pasture microclimate did not correlate with larval recovery. At the end of the experiment, the animal fecal egg count was similar among treatments (P > 0.05). The results indicated that different lamb feeding systems in a tropical erect grassland caused differences in grass height but did not affect the distribution of infective larvae among strata. Larvae were found from the base to the top of the grass sward. PMID:26003429

  9. Preference for different inorganic nitrogen forms among plant functional types and species of the Patagonian steppe.

    PubMed

    Gherardi, Laureano A; Sala, Osvaldo E; Yahdjian, Laura

    2013-11-01

    We have explored species-specific preferences for nitrate (NO3(-)) and ammonium (NH4(+)) as an alternative niche separation in ecosystems where nitrogen (N) is present mostly in inorganic forms. The Patagonian steppe is dominated by shrubs and grasses. Shrubs absorb water and nutrients from deep soil layers, which are poor in N, while grasses have the opposite pattern, absorbing most of their water and nutrients from the upper layers of the soil. We hypothesized that the preferences of shrub and grass for inorganic N forms are different and that the rate of potential N uptake is greater in shrubs than in grasses. To test this hypothesis, we grew individuals of six dominant species in solutions of different NH4(+):NO3(-) concentration ratios. Nitrate uptake was found to be higher in shrubs, while ammonium uptake was similar between plant functional types. The NH4(+):NO3(-) uptake ratio was significantly lower for shrubs than grasses. Shrubs, which under field conditions have deeper rooting systems than grasses, showed a higher N absorption capacity than grasses and a preference for the more mobile N form, nitrate. Grasses, which had lower N uptake rates than shrubs, preferred ammonium over nitrate. These complementary patterns between grasses and shrubs suggest a more thorough exploitation of resources by diverse ecosystems than those dominated by just one functional type. The loss of one plant functional group or a significant change in its abundance would therefore represent a reduction in resource use efficiency and ecosystem functioning. PMID:23812108

  10. Soil modification by invasive plants: Effects on native and invasive species of mixed-grass prairies

    USGS Publications Warehouse

    Jordan, N.R.; Larson, D.L.; Huerd, S.C.

    2008-01-01

    Invasive plants are capable of modifying attributes of soil to facilitate further invasion by conspecifics and other invasive species. We assessed this capability in three important plant invaders of grasslands in the Great Plains region of North America: leafy spurge (Euphorbia esula), smooth brome (Bromus inermis) and crested wheatgrass (Agropyron cristatum). In a glasshouse, these three invasives or a group of native species were grown separately through three cycles of growth and soil conditioning in both steam-pasteurized and non-pasteurized soils, after which we assessed seedling growth in these soils. Two of the three invasive species, Bromus and Agropyron, exhibited significant self-facilitation via soil modification. Bromus and Agropyron also had significant facilitative effects on other invasives via soil modification, while Euphorbia had significant antagonistic effects on the other invasives. Both Agropyron and Euphorbia consistently suppressed growth of two of three native forbs, while three native grasses were generally less affected. Almost all intra- and interspecific effects of invasive soil conditioning were dependent upon presence of soil biota from field sites where these species were successful invaders. Overall, these results suggest that that invasive modification of soil microbiota can facilitate plant invasion directly or via 'cross-facilitation' of other invasive species, and moreover has potential to impede restoration of native communities after removal of an invasive species. However, certain native species that are relatively insensitive to altered soil biota (as we observed in the case of the forb Linum lewisii and the native grasses), may be valuable as 'nurse'species in restoration efforts. ?? 2007 Springer Science+Business Media B.V.

  11. Factors associated with plant species richness in a coastal tall-grass prairie

    USGS Publications Warehouse

    Grace, J.B.; Allain, L.; Allen, C.

    2000-01-01

    In this study we examine the factors associated with variations in species richness within a remnant tall-grass prairie in order to gain insight into the relative importance of controlling variables. The study area was a small, isolated prairie surrounded by wetlands and located within the coastal prairie region, which occurs along the northwestern Gulf of Mexico coastal plain. Samples were taken along three transects that spanned the prairie. Parameters measured included micro-elevation, soil characteristics, indications of recent disturbance, above-ground biomass (including litter), light penetration through the plant canopy, and species richness. Species richness was found to correlate with micro-elevation, certain soil parameters, and light penetration through the canopy, but not with above-ground biomass. Structural equation analysis was used to assess the direct and indirect effects of micro-elevation, soil properties, disturbance, and indicators of plant abundance on species richness. The results of this analysis showed that observed variations in species richness were primarily associated with variations in environmental effects (from soil and microtopography) and were largely unrelated to variations in measures of plant abundance (biomass and light penetration). These findings suggest that observed variations in species richness in this system primarily resulted from environmental effects on the species pool. These results fit with a growing body of information that suggests that environmental effects on species richness are of widespread importance.

  12. Two distinct Epichloë species symbiotic with Achnatherum inebrians, drunken horse grass.

    PubMed

    Chen, Li; Li, Xiuzhang; Li, Chunjie; Swoboda, Ginger A; Young, Carolyn A; Sugawara, Koya; Leuchtmann, Adrian; Schardl, Christopher L

    2015-01-01

    Achnatherum inebrians, colloquially known as drunken horse grass, is associated with livestock toxicity in northern China. Epichloë gansuensis (Eg) was described from endophyte isolates from A. inebrians in Sunan County, Gansu Province, whereas a morphologically distinct variety, E. gansuensis var. inebrians (Ei), was described based on two isolates from A. inebrians seeds collected in Urumqi County, Xinjiang Province. Genome sequencing and alkaloid analyses also distinguish these taxa; the Ei isolates produce neurotropic lysergic acid amides (ergot alkaloids), and an Eg isolate produces paxilline (an indole-diterpene alkaloid). To better elucidate the taxonomic diversity of Epichloë spp. symbiotic with A. inebrians, we surveyed eight populations in Xinjiang, Gansu and Inner Mongolia provinces of China and analyzed their genotypes by multiplex PCR for alkaloid biosynthesis genes and mating-type genes. Genotypes consistent with Ei were present in all eight populations, of which they dominated seven. The Ei isolates were all mating type A and tested positive for the ergot alkaloid gene, dmaW. In contrast Eg isolates were all mating type B and had the indole-diterpene gene, idtG. The genome was sequenced from an Ei isolate from seeds collected in Xiahe County, Gansu, and compared to that of the varietal ex type isolate from Urumqi. Alkaloid genes and four different housekeeping genes were nearly identical between the two sequenced Ei isolates and were distinct from a sequenced Eg isolate. Phylogenetic analysis placed Ei, Eg and Epichloë sibirica into respective subclades of a clade that emanated from the base of the Epichloë phylogeny. Given its chemotypic, genotypic, morphological and phylogenetic distinctiveness, its widespread occurrence in rangelands of northern China, and its importance in livestock toxicity, we propose raising Ei to species rank as Epichloë inebrians. PMID:25911697

  13. Grass pollen allergens globally: the contribution of subtropical grasses to burden of allergic respiratory diseases.

    PubMed

    Davies, J M

    2014-06-01

    Grass pollens of the temperate (Pooideae) subfamily and subtropical subfamilies of grasses are major aeroallergen sources worldwide. The subtropical Chloridoideae (e.g. Cynodon dactylon; Bermuda grass) and Panicoideae (e.g. Paspalum notatum; Bahia grass) species are abundant in parts of Africa, India, Asia, Australia and the Americas, where a large and increasing proportion of the world's population abide. These grasses are phylogenetically and ecologically distinct from temperate grasses. With the advent of global warming, it is conceivable that the geographic distribution of subtropical grasses and the contribution of their pollen to the burden of allergic rhinitis and asthma will increase. This review aims to provide a comprehensive synthesis of the current global knowledge of (i) regional variation in allergic sensitivity to subtropical grass pollens, (ii) molecular allergenic components of subtropical grass pollens and (iii) allergic responses to subtropical grass pollen allergens in relevant populations. Patients from subtropical regions of the world show higher allergic sensitivity to grass pollens of Chloridoideae and Panicoideae grasses, than to temperate grass pollens. The group 1 allergens are amongst the allergen components of subtropical grass pollens, but the group 5 allergens, by which temperate grass pollen extracts are standardized for allergen content, appear to be absent from both subfamilies of subtropical grasses. Whilst there are shared allergenic components and antigenic determinants, there are additional clinically relevant subfamily-specific differences, at T- and B-cell levels, between pollen allergens of subtropical and temperate grasses. Differential immune recognition of subtropical grass pollens is likely to impact upon the efficacy of allergen immunotherapy of patients who are primarily sensitized to subtropical grass pollens. The literature reviewed herein highlights the clinical need to standardize allergen preparations for both

  14. Detection and Isolation of Epichloë Species, Fungal Endophytes of Grasses.

    PubMed

    Florea, Simona; Schardl, Christopher L; Hollin, Walter

    2015-01-01

    Epichloë species (including former Neotyphodium species) are endophytic fungi that significantly affect fitness of cool-season grass hosts, potentially by increasing nutrient uptake and resistance to drought, parasitism and herbivory. Epichloë species are obligately biotrophic, living in the intercellular spaces of their plant hosts, and spreading systemically throughout host aerial tissues. The reproduction of Epichloë species is versatile; some strains have both sexual and asexual modes of reproduction, but others are restricted to one or the other mode. The reproduction mode determines the dissemination mechanism, and the asexual species most important to agriculture are strictly seed-borne, cause no signs or symptoms, and are undetectable except by specialized microscopic, molecular or antigenic procedures. These procedures can be used to identify endophytes in a variety of plant tissues. Similar protocols can be modified to detect less common symbionts, such as the penicillate "p-endophytes," when they occur by themselves or together with Epichloë species. PMID:26237108

  15. Persistence of biological nitrogen fixation in high latitude grass-clover grasslands under different management practices

    NASA Astrophysics Data System (ADS)

    Tzanakakis, Vasileios; Sturite, Ievina; Dörsch, Peter

    2016-04-01

    Biological nitrogen fixation (BNF) can substantially contribute to N supply in permanent grasslands, improving N yield and forage quality, while reducing inorganic N inputs. Among the factors critical to the performance of BNF in grass-legume mixtures are selected grass and legume species, proportion of legumes, the soil-climatic conditions, in particular winter conditions, and management practices (e.g. fertilization and compaction). In high latitude grasslands, low temperatures can reduce the performance of BNF by hampering the legumés growth and by suppressing N2 fixation. Estimation of BNF in field experiments is not straightforward. Different methods have been developed providing different results. In the present study, we evaluated the performance of BNF, in a newly established field experiment in North Norway over four years. The grassland consisted of white clover (Trifolium repens L.) and red clover (Trifolium pretense L.) sawn in three proportions (0, 15 and 30% in total) together with timothy (Pheum pretense L.) and meadow fescue (Festuca pratensis L.). Three levels of compaction were applied each year (no tractor, light tractor, heavy tractor) together with two different N rates (110 kg N/ha as cattle slurry or 170 kg N/ha as cattle slurry and inorganic N fertilizer). We applied two different methods, the 15N natural abundance and the difference method, to estimate BNF in the first harvest of each year. Overall, the difference method overestimated BNF relative to the 15N natural abundance method. BNF in the first harvest was compared to winter survival of red and white clover plants, which decreased with increasing age of the grassland. However, winter conditions did not seem to affect the grassland's ability to fix N in spring. The fraction of N derived from the atmosphere (NdfA) in white and red clover was close to 100% in each spring, indicating no suppression of BNF. BNF increased the total N yield of the grasslands by up to 75%, mainly due to high

  16. Influence of different chemical pretreatments of elephant grass (Pennisetum purpureum, Schum.) used as a substrate for cellulase and xylanase production in submerged cultivation.

    PubMed

    Menegol, Daiane; Scholl, Angélica Luisi; Dillon, Aldo José Pinheiro; Camassola, Marli

    2016-09-01

    This study evaluated the potential use of elephant grass biomass, a highly productive species, for cellulase and xylanase production by the cellulolytic mutant Penicillium echinulatum 9A02S1 in submerged cultivation, using untreated biomass, biomass pretreated with different concentrations of NaOH, H2SO4 or NH4OH, or biomass pretreated with H2O at 121 °C. For filter paper activity, all cultivation carried out with pretreated elephant grass under the evaluated conditions showed superior activity when compared with the control (untreated elephant grass). The activities of endoglucanases and β-glucosidases were higher in the cultivation prepared from pretreated samples than the control made with cellulose (Celuflok(®)). Without pretreatment, elephant grass can be used for xylanase production, enabling similar activities to those obtained in the cultivation with cellulose, reducing the enzyme production cost. These results indicate that the pretreatment of elephant grass, especially when pretreated with H2SO4, may be used as a partial or total replacement for cellulose to cellulase production, and untreated elephant grass may be used for xylanase production. PMID:27164962

  17. Consequences of Seed Origin and Biological Invasion for Early Establishment in Restoration of a North American Grass Species

    PubMed Central

    Herget, Mollie E.; Hufford, Kristina M.; Mummey, Daniel L.; Shreading, Lauren N.

    2015-01-01

    Local, wild-collected seeds of native plants are recommended for use in ecological restoration to maintain patterns of adaptive variation. However, some environments are so drastically altered by exotic, invasive weeds that original environmental conditions may no longer exist. Under these circumstances, cultivated varieties selected for improved germination and vigor may have a competitive advantage at highly disturbed sites. This study investigated differences in early establishment and seedling performance between wild and cultivated seed sources of the native grass, Poa secunda, both with and without competition from the invasive exotic grass, Bromus tectorum. We measured seedling survival and above-ground biomass at two experimental sites in western Montana, and found that the source of seeds selected for restoration can influence establishment at the restoration site. Cultivars had an overall advantage when compared with local genotypes, supporting evidence of greater vigor among cultivated varieties of native species. This advantage, however, declined rapidly in the presence of B. tectorum and most accessions were not significantly different for growth and survival in competition plots. Only one cultivar had a consistent advantage despite a strong decline in its performance when competing with invasive plants. As a result, cultivated varieties did not meet expectations for greater establishment and persistence relative to local genotypes in the presence of invasive, exotic species. We recommend the use of representative local or regional wild seed sources in restoration to minimize commercial selection, and a mix of individual accessions (wild, or cultivated when necessary) in highly invaded settings to capture vigorous genotypes and increase the odds native plants will establish at restoration sites. PMID:25741702

  18. An evaluation of the use of individual grass species in retaining polluted soil and dust particulates in vegetated sustainable drainage devices.

    PubMed

    Charlesworth, S M; Bennett, J; Waite, A

    2016-08-01

    A sustainable means of preventing polluted particulates carried in urban storm water entering rivers, groundwater and lakes is by employing vegetated sustainable drainage system (SUDS) devices, or best management practices to trap or biodegrade them. In the UK, a mixture of grass species is recommended for use in devices such as swales or filter strips. However, there is little evidence in support of the efficiency of the individual grasses or mixtures to deal with such contaminated material. A pot-based pollutant retention study was conducted using processed street dust from central Coventry, UK, as a simulated pollutant to be applied in different quantities to a variety of recommended grasses for vegetated SUDS devices. Analysis was conducted on compost cores, roots and shoots for heavy metals (Cd, Cu, Ni, Pb and Zn). Street dust mainly concentrated in the top compost layer for all grasses with only the finer material migrating down the profile. Analysis of roots indicated little accumulation, with ANOVA statistical tests indicating significant differences in heavy metal concentrations, with less in the compost and more in the shoots. Development of root systems on or near the surface possibly explains increased uptake of heavy metals by some species. Overall Agrostis canina and Poa pratensis showed the greatest accumulations compared to their controls although Agrostis capillaris syn.tenuis and Agrostis stolonifera also demonstrated accumulation potential. On ranking, Agrostis canina and Poa pratensis were highest overall. These rankings will assist in selecting the best grasses to address pollution of the urban environment by contaminated particulates. PMID:26753553

  19. Identification and characterization of an expansin gene AsEXP1 associated with heat tolerance in C3 Agrostis grass species.

    PubMed

    Xu, Jichen; Tian, Jiang; Belanger, Faith C; Huang, Bingru

    2007-01-01

    Plant tolerance of heat stress involves various changes at physiological and molecular levels. The objective of this study was to examine the expression of a gene encoding expansin protein in relation to heat tolerance in two C(3) grass species and genotypes differing in heat tolerance. Heat-tolerant, thermal Agrostis scabra, adapted to high temperatures in geothermal areas in Yellowstone National Park, was subjected to 20 degrees C (control) or 40 degrees C (heat stress) for 7 d in a growth chamber. Differential display analysis identified that a gene, AsEXP1, encoding an expansin protein, was strongly up-regulated in leaves exposed to heat stress in thermal A. scabra. Virtual northern hybridization and RT-PCR confirmed that AsEXP1 was a heat-inducible gene in leaves. The expression of AsEXP1 was induced at 1 h of plant exposure to heat stress and reached the highest level of expression at 4 h of treatment. A 1.3 kb full-length cDNA of AsEXP1 was isolated, which encodes a 251 amino acid protein. Two ecotypes of thermal A. scabra and 10 genotypes of Agrostis stolonifera (creeping bentgrass), a widely used turfgrass species in cool climatic regions, varying in the level of heat tolerance, were exposed to 40 degrees C for 7 d to examine the level of AsEXP1 expression in relation to heat tolerance. Genetic variation in heat tolerance was evaluated by measuring cell membrane stability, photochemical efficiency, and leaf growth. RT-PCR analysis revealed that the level of AsEXP1 in different genotypes was positively correlated with the level of heat tolerance in both grass species. The results first identified a heat-related expansin gene in grass species and suggest that AsEXP1 may be useful as a molecular marker to select for heat-tolerant grass germplasm. PMID:17928368

  20. ECOLOGICAL DETERMINANTS OF POPULATION STRUCTURE AND GENE FLOW BETWEEN SYMPATRIC FUNGAL SPECIES IN THE GENUS COLLEOTRICHUM FROM DIVERSE GRASS COMMUNITIES

    EPA Science Inventory

    This comparative analysis will allow us to detect historical events of interest such as population fragmentations, range expansions, and colonization in the Colletotrichum species that inhabit pooid grasses. What is learned from C. cereale populations in agro...

  1. Cloning and characterization of a salt stress-inducible small GTPase gene from the model grass species Lolium temulentum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A gene encoding a small GTP binding protein (smGTP) related to the Rab2 gene family of GTPases was identified during the analysis of a salt stress suppression subtractive hybridization (SSH) expression library from the model grass species Lolium temulentum L. (Darnel ryegrass). The smGTP gene was fo...

  2. Tree species from different functional groups respond differently to environmental changes during establishment.

    PubMed

    Barbosa, Eduardo R M; van Langevelde, Frank; Tomlinson, Kyle W; Carvalheiro, Luísa G; Kirkman, Kevin; de Bie, Steven; Prins, Herbert H T

    2014-04-01

    Savanna plant communities change considerably across time and space. The processes driving savanna plant species diversity, coexistence and turnover along environmental gradients are still unclear. Understanding how species respond differently to varying environmental conditions during the seedling stage, a critical stage for plant population dynamics, is needed to explain the current composition of plant communities and to enable us to predict their responses to future environmental changes. Here we investigate whether seedling response to changes in resource availability, and to competition with grass, varied between two functional groups of African savanna trees: species with small leaves, spines and N-fixing associations (fine-leaved species), and species with broad leaves, no spines, and lacking N-fixing associations (broad-leaved species). We show that while tree species were strongly suppressed by grass, the effect of resource availability on seedling performance varied considerably between the two functional groups. Nutrient inputs increased stem length only of broad-leaved species and only under an even watering treatment. Low light conditions benefited mostly broad-leaved species' growth. Savannas are susceptible to ongoing global environment changes. Our results suggest that an increase in woody cover is only likely to occur in savannas if grass cover is strongly suppressed (e.g. by fire or overgrazing). However, if woody cover does increase, broad-leaved species will benefit most from the resulting shaded environments, potentially leading to an expansion of the distribution of these species. Eutrophication and changes in rainfall patterns may also affect the balance between fine- and broad-leaved species. PMID:24337711

  3. Draft genome sequences of three Xanthomonas translucens pathovar reference strains (pv. arrhenatheri, pv. poae and pv. phlei) with different specificities for forage grasses.

    PubMed

    Hersemann, Lena; Wibberg, Daniel; Widmer, Franco; Vorhölter, Frank-Jörg; Kölliker, Roland

    2016-01-01

    As causal agents of bacterial wilt in pastures and meadows, bacteria of the species Xanthomonas translucens are a serious issue in forage grass production. So far, only little is known about host-pathogen interactions at the molecular level and the lack of comprehensive genome data impeded targeted breeding strategies towards resistant forage grass cultivars. Here we announce the draft genome sequences of three grass-pathogenic Xanthomonas translucens pathotype strains, i.e. pv. arrhenatheri LMG 727, pv. poae LMG 728 and pv. phlei LMG 730 isolated from Arrhenatherum elatius (L.) P. Beauv. ex J. Presl & C. Presl (Switzerland), Poa trivialis L. (Switzerland) and Phleum pratense L. (Norway), respectively. The genomes of all three strains revealed a non-canonical type III secretion system and a set of 22 type III effectors as common virulence-related traits. Distinct inter-pathovar differences were observed for the lipopolysaccharide biosynthesis gene cluster and the presence of nonribosomal peptide synthetases. PMID:27536340

  4. Modeling greenup date of dominant grass species in the Inner Mongolian Grassland using air temperature and precipitation data

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoqiu; Li, Jing; Xu, Lin; Liu, Li; Ding, Deng

    2014-05-01

    This work was undertaken to examine the combined effect of air temperature and precipitation during late winter and early spring on modeling greenup date of grass species in the Inner Mongolian Grassland. We used the traditional thermal time model and developed two revised thermal time models coupling air temperature and precipitation to simulate greenup date of three dominant grass species at six stations from 1983 to 2009. Results show that climatic controls on greenup date of grass species were location-specific. The revised thermal time models coupling air temperature and precipitation show higher simulation parsimony and efficiency than the traditional thermal time model for five of 11 data sets at Bayartuhushuo, Xilinhot and Xianghuangqi, whereas the traditional thermal time model indicates higher simulation parsimony and efficiency than the revised thermal time models coupling air temperature and precipitation for the other six data sets at E'ergunayouqi, Ewenkeqi and Chaharyouyihouqi. The mean root mean square error of the 11 models is 4.9 days. Moreover, the influence of late winter and early spring precipitation on greenup date seems to be stronger at stations with scarce precipitation than at stations with relatively abundant precipitation. From the mechanism perspectives, accumulated late winter and early spring precipitation may play a more important role as the precondition of forcing temperature than as the supplementary condition of forcing temperature in triggering greenup. Our findings suggest that predicting responses of grass phenology to global climate change should consider both thermal and moisture scenarios in some semiarid and arid areas.

  5. Translational Genomics for Bioenergy Production from Fuelstock Grasses: Maize as the Model Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Meeting U.S. and world energy needs using biofuels rests on our ability to improve grasses that use the efficient C4 photosynthetic pathway in which carbon dioxide concentrating mechanisms sustain high biomass production, particularly when water is limiting. Today two C4 grasses yield substantial e...

  6. Gibberellin-Stimulation of Rhizome Elongation and Differential GA-Responsive Proteomic Changes in Two Grass Species.

    PubMed

    Ma, Xiqing; Huang, Bingru

    2016-01-01

    Rapid and extensive rhizome development is a desirable trait for perennial grass growth and adaptation to environmental stresses. The objective of this study was to determine proteomic changes and associated metabolic pathways of gibberellin (GA) -regulation of rhizome elongation in two perennial grass species differing in rhizome development. Plants of a short-rhizome bunch-type tall fescue (TF; Festuca arundinacea; 'BR') and an extensive rhizomatous Kentucky bluegrass (KB; Poa pratensis; 'Baron') were treated with 10 μM GA3 in hydroponic culture in growth chambers. The average rhizome length in KB was significantly longer than that in TF regardless of GA3 treatment, and increased significantly with GA3 treatment, to a greater extent than that in TF. Comparative proteomic analysis using two-dimensional electrophoresis and mass spectrometry was performed to further investigate proteins and associated metabolic pathways imparting increased rhizome elongation by GA. A total of 37 and 38 differentially expressed proteins in response to GA3 treatment were identified in TF and KB plants, respectively, which were mainly involved in photosynthesis, energy and amino acid metabolism, protein synthesis, defense and cell development processes. Accelerated rhizome elongation in KB by GA could be mainly associated with the increased abundance of proteins involved in energy metabolism (glyceraldehyde-3-phosphate dehydrogenase, fructose-bisphosphate aldolase, and ATP synthase), amino acid metabolism (S-adenosylmethionine and adenosylhomocysteinase), protein synthesis (HSP90, elongation factor Tu and eukaryotic translation initiation factor 5A), cell-wall development (cell dividion cycle protein, alpha tubulin-2A and actin), and signal transduction (calreticulin). These proteins could be used as candidate proteins for further analysis of molecular mechanisms controlling rhizome growth. PMID:27446135

  7. Gibberellin-Stimulation of Rhizome Elongation and Differential GA-Responsive Proteomic Changes in Two Grass Species

    PubMed Central

    Ma, Xiqing; Huang, Bingru

    2016-01-01

    Rapid and extensive rhizome development is a desirable trait for perennial grass growth and adaptation to environmental stresses. The objective of this study was to determine proteomic changes and associated metabolic pathways of gibberellin (GA) -regulation of rhizome elongation in two perennial grass species differing in rhizome development. Plants of a short-rhizome bunch-type tall fescue (TF; Festuca arundinacea; ‘BR’) and an extensive rhizomatous Kentucky bluegrass (KB; Poa pratensis; ‘Baron’) were treated with 10 μM GA3 in hydroponic culture in growth chambers. The average rhizome length in KB was significantly longer than that in TF regardless of GA3 treatment, and increased significantly with GA3 treatment, to a greater extent than that in TF. Comparative proteomic analysis using two-dimensional electrophoresis and mass spectrometry was performed to further investigate proteins and associated metabolic pathways imparting increased rhizome elongation by GA. A total of 37 and 38 differentially expressed proteins in response to GA3 treatment were identified in TF and KB plants, respectively, which were mainly involved in photosynthesis, energy and amino acid metabolism, protein synthesis, defense and cell development processes. Accelerated rhizome elongation in KB by GA could be mainly associated with the increased abundance of proteins involved in energy metabolism (glyceraldehyde-3-phosphate dehydrogenase, fructose-bisphosphate aldolase, and ATP synthase), amino acid metabolism (S-adenosylmethionine and adenosylhomocysteinase), protein synthesis (HSP90, elongation factor Tu and eukaryotic translation initiation factor 5A), cell-wall development (cell dividion cycle protein, alpha tubulin-2A and actin), and signal transduction (calreticulin). These proteins could be used as candidate proteins for further analysis of molecular mechanisms controlling rhizome growth. PMID:27446135

  8. Flavor, glucosinolates, and isothiocyanates of nau (Cook's scurvy grass, Lepidium oleraceum) and other rare New Zealand Lepidium species.

    PubMed

    Sansom, Catherine E; Jones, Veronika S; Joyce, Nigel I; Smallfield, Bruce M; Perry, Nigel B; van Klink, John W

    2015-02-18

    The traditionally consumed New Zealand native plant nau, Cook's scurvy grass, Lepidium oleraceum, has a pungent wasabi-like taste, with potential for development as a flavor ingredient. The main glucosinolate in this Brassicaceae was identified by LC-MS and NMR spectroscopy as 3-butenyl glucosinolate (gluconapin, 7-22 mg/g DM in leaves). The leaves were treated to mimic chewing, and the headspace was analyzed by solid-phase microextraction and GC-MS. This showed that 3-butenyl isothiocyanate, with a wasabi-like flavor, was produced by the endogenous myrosinase. Different postharvest treatments were used to create leaf powders as potential flavor products, which were tasted and analyzed for gluconapin and release of 3-butenyl isothiocyanate. A high drying temperature (75 °C) did not give major glucosinolate degradation, but did largely inactivate the myrosinase, resulting in no wasabi-like flavor release. Drying at 45 °C produced more pungent flavor than freeze-drying. Seven other Lepidium species endemic to New Zealand were also analyzed to determine their flavor potential and also whether glucosinolates were taxonomic markers. Six contained mostly gluconapin, but the critically endangered Lepidium banksii had a distinct composition including isopropyl glucosinolate, not detected in the other species. PMID:25625566

  9. Attenuation of foot pressure during running on four different surfaces: asphalt, concrete, rubber, and natural grass.

    PubMed

    Tessutti, Vitor; Ribeiro, Ana Paula; Trombini-Souza, Francis; Sacco, Isabel C N

    2012-01-01

    The practice of running has consistently increased worldwide, and with it, related lower limb injuries. The type of running surface has been associated with running injury etiology, in addition other factors, such as the relationship between the amount and intensity of training. There is still controversy in the literature regarding the biomechanical effects of different types of running surfaces on foot-floor interaction. The aim of this study was to investigate the influence of running on asphalt, concrete, natural grass, and rubber on in-shoe pressure patterns in adult recreational runners. Forty-seven adult recreational runners ran twice for 40 m on all four different surfaces at 12 ± 5% km · h(-1). Peak pressure, pressure-time integral, and contact time were recorded by Pedar X insoles. Asphalt and concrete were similar for all plantar variables and pressure zones. Running on grass produced peak pressures 9.3% to 16.6% lower (P < 0.001) than the other surfaces in the rearfoot and 4.7% to 12.3% (P < 0.05) lower in the forefoot. The contact time on rubber was greater than on concrete for the rearfoot and midfoot. The behaviour of rubber was similar to that obtained for the rigid surfaces - concrete and asphalt - possibly because of its time of usage (five years). Running on natural grass attenuates in-shoe plantar pressures in recreational runners. If a runner controls the amount and intensity of practice, running on grass may reduce the total stress on the musculoskeletal system compared with the total musculoskeletal stress when running on more rigid surfaces, such as asphalt and concrete. PMID:22897427

  10. Native Grasses as a Management Alternative on Vegetated Closure Caps

    NASA Astrophysics Data System (ADS)

    Kwit, Charles; Collins, Beverly

    2008-06-01

    Capped waste sites often are vegetated with commercial turf grasses to increase evapotranspiration and prevent erosion and possible exposure of the barrier. Fertilizer, frequent watering, and mowing may be required to establish the turf grass and prevent invasion by trees and shrubs. Oldfield vegetation of grasses and forbs is a possible sustainable alternative to turf grass communities. To determine if oldfield vegetation can establish on caps, we (1) compared establishment of a dominant oldfield grass and a commercial turf grass under different combinations of new closure cap management: spring or summer planting and presence or absence of amendments to alleviate drought (watering, mulch) or increase soil fertility (fertilizer, lime, a nitrogen-fixing legume); (2) surveyed existing caps to determine if oldfield species establish naturally; and (3) performed a greenhouse experiment to compare growth of two native grasses under low and amended (added water, soil nutrients) conditions. Both the commercial grass and oldfield species established under new cap conditions; fertilizer, water, and mulch improved vegetation establishment in spring or summer, but legumes decreased grass cover. In the greenhouse, both native grasses grew best with amendments; however, substantial stem and root length were obtained with no fertilizer and only once-weekly watering. Existing vegetated caps supported planted grasses and naturally established oldfield species. Overall, the results indicate native grasses can establish on new caps and oldfields can serve as a management model; further work is needed to determine the management strategy to maintain herbaceous vegetation and slow woody species invasion.

  11. PHYTOREMEDIATION OF ATRAZINE BY FIVE FORAGE GRASS SPECIES: TRANSFORMATION, UPTAKE AND DETOXIFICATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A sound multi-species vegetation buffer design should incorporate the species that facilitate rapid degradation and sequestration of deposited herbicides in the buffer. A field lysimeter study with six different ground covers (bare ground, orchardgrass, tall fescue, timothy, smooth bromegrass, and s...

  12. Modeling greenup date of dominant grass species in the Inner Mongolian Grassland using air temperature and precipitation data.

    PubMed

    Chen, Xiaoqiu; Li, Jing; Xu, Lin; Liu, Li; Ding, Deng

    2014-05-01

    This work was undertaken to examine the combined effect of air temperature and precipitation during late winter and early spring on modeling greenup date of grass species in the Inner Mongolian Grassland. We used the traditional thermal time model and developed two revised thermal time models coupling air temperature and precipitation to simulate greenup date of three dominant grass species at six stations from 1983 to 2009. Results show that climatic controls on greenup date of grass species were location-specific. The revised thermal time models coupling air temperature and precipitation show higher simulation parsimony and efficiency than the traditional thermal time model for five of 11 data sets at Bayartuhushuo, Xilinhot and Xianghuangqi, whereas the traditional thermal time model indicates higher simulation parsimony and efficiency than the revised thermal time models coupling air temperature and precipitation for the other six data sets at E'ergunayouqi, Ewenkeqi and Chaharyouyihouqi. The mean root mean square error of the 11 models is 4.9 days. Moreover, the influence of late winter and early spring precipitation on greenup date seems to be stronger at stations with scarce precipitation than at stations with relatively abundant precipitation. From the mechanism perspectives, accumulated late winter and early spring precipitation may play a more important role as the precondition of forcing temperature than as the supplementary condition of forcing temperature in triggering greenup. Our findings suggest that predicting responses of grass phenology to global climate change should consider both thermal and moisture scenarios in some semiarid and arid areas. PMID:24065573

  13. Classification of images of wheat, ryegrass and brome grass species at early growth stages using principal component analysis

    PubMed Central

    2011-01-01

    Wheat is one of the most important crops in Australia, and the identification of young plants is an important step towards developing an automated system for monitoring crop establishment and also for differentiating crop from weeds. In this paper, a framework to differentiate early narrow-leaf wheat from two common weeds from their digital images is developed. A combination of colour, texture and shape features is used. These features are reduced to three descriptors using Principal Component Analysis. The three components provide an effective and significant means for distinguishing the three grasses. Further analysis enables threshold levels to be set for the discrimination of the plant species. The PCA model was evaluated on an independent data set of plants and the results show accuracy of 88% and 85% in the differentiation of ryegrass and brome grass from wheat, respectively. The outcomes of this study can be integrated into new knowledge in developing computer vision systems used in automated weed management. PMID:21943349

  14. Optimization of delignification of two Pennisetum grass species by NaOH pretreatment using Taguchi and ANN statistical approach.

    PubMed

    Mohaptra, Sonali; Dash, Preeti Krishna; Behera, Sudhanshu Shekar; Thatoi, Hrudayanath

    2016-01-01

    In the bioconversion of lignocelluloses for bioethanol, pretreatment seems to be the most important step which improves the elimination of the lignin and hemicelluloses content, exposing cellulose to further hydrolysis. The present study discusses the application of dynamic statistical techniques like the Taguchi method and artificial neural network (ANN) in the optimization of pretreatment of lignocellulosic biomasses such as Hybrid Napier grass (HNG) (Pennisetum purpureum) and Denanath grass (DG) (Pennisetum pedicellatum), using alkali sodium hydroxide. This study analysed and determined a parameter combination with a low number of experiments by using the Taguchi method in which both the substrates can be efficiently pretreated. The optimized parameters obtained from the L16 orthogonal array are soaking time (18 and 26 h), temperature (60°C and 55°C), and alkali concentration (1%) for HNG and DG, respectively. High performance liquid chromatography analysis of the optimized pretreated grass varieties confirmed the presence of glucan (47.94% and 46.50%), xylan (9.35% and 7.95%), arabinan (2.15% and 2.2%), and galactan/mannan (1.44% and 1.52%) for HNG and DG, respectively. Physicochemical characterization studies of native and alkali-pretreated grasses were carried out by scanning electron microscopy and Fourier transformation Infrared spectroscopy which revealed some morphological differences between the native and optimized pretreated samples. Model validation by ANN showed a good agreement between experimental results and the predicted responses. PMID:26584152

  15. Individual differences in rhythms of behavioral sleep and its neural substrates in Nile grass rats.

    PubMed

    Schwartz, M D; Smale, L

    2005-12-01

    Laboratory populations of grass rats (Arvicanthis niloticus) housed with a running wheel show considerable variation in patterns of locomotor activity. At the extremes are "day-active" (DA) animals with a monophasic distribution of running throughout the light phase and "night-active" (NA) animals exhibiting a biphasic pattern with an extended peak at the beginning of the dark phase and a brief peak shortly before lights-on. Here, the authors use this intraspecific variation to explore interactions between circadian and homeostatic influences on sleep and the effects of these interactions on the activity of brain regions involved in sleep regulation. Male animals were singly housed with running wheels in a 12:12 LD cycle, videotaped for 24 h, and perfused at ZT 4 or 16. Behavioral sleep was scored from the videotapes, and brains were processed for cFos immunoreactivity (cFos-ir). Sleep duration within the light and dark phases was higher in NA and DA animals, respectively, but these groups did not differ with respect to total sleep. In both groups, sleep bouts were shortest in the light phase and longest between ZT 20 and ZT 23. In the ventrolateral preoptic area (VLPO), cFos-ir was higher at ZT 16 than at ZT 4 in DA but not NA grass rats, and it was correlated with behavioral sleep at ZT 16 but not ZT 4. In OXA neurons, cFos-ir was high at ZT 4 in DA grass rats and at ZT 16 in NA grass rats, and it was correlated with behavioral sleep at both times. In the lower subparaventricular zone (LSPV), cFos-ir was higher at ZT 16 in both DA and NA animals, and it was unrelated to behavioral sleep. Thus, patterns of cFos-ir in the LSPV and OXA neurons were most tightly linked to time and sleep, respectively, whereas cFos-ir in the VLPO was influenced by an interaction between these 2 variables. PMID:16275771

  16. Growth and Quality of Cool-Season Perennial Grass Species in the Southern Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Annually planted winter wheat is the major cool-season livestock forage enterprise in a large part of the southern Great Plains and is a good complement to warm-season perennials. However, gaps in both fall and spring exist in the system. Cool-season perennial grasses that have origins in the Nort...

  17. Native Grass Canopy Management and Species Mixture Effects on Soil C and N

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are 2.9 million conservation reserve program (CRP) acres in South Dakota and Minnesota. This region is also slated to provide cellulosic feedstocks for biofuels. Thus, scientific inquiry on the effect of CRP/grass management on soil condition is an important priority. Experiment objectives ...

  18. Automated conserved non-coding sequence (CNS) discovery reveals differences in gene content and promoter evolution among grasses

    PubMed Central

    Turco, Gina; Schnable, James C.; Pedersen, Brent; Freeling, Michael

    2013-01-01

    Conserved non-coding sequences (CNS) are islands of non-coding sequence that, like protein coding exons, show less divergence in sequence between related species than functionless DNA. Several CNSs have been demonstrated experimentally to function as cis-regulatory regions. However, the specific functions of most CNSs remain unknown. Previous searches for CNS in plants have either anchored on exons and only identified nearby sequences or required years of painstaking manual annotation. Here we present an open source tool that can accurately identify CNSs between any two related species with sequenced genomes, including both those immediately adjacent to exons and distal sequences separated by >12 kb of non-coding sequence. We have used this tool to characterize new motifs, associate CNSs with additional functions, and identify previously undetected genes encoding RNA and protein in the genomes of five grass species. We provide a list of 15,363 orthologous CNSs conserved across all grasses tested. We were also able to identify regulatory sequences present in the common ancestor of grasses that have been lost in one or more extant grass lineages. Lists of orthologous gene pairs and associated CNSs are provided for reference inbred lines of arabidopsis, Japonica rice, foxtail millet, sorghum, brachypodium, and maize. PMID:23874343

  19. Attacking invasive grasses

    USGS Publications Warehouse

    Keeley, Jon E.

    2015-01-01

    In grasslands fire may play a role in the plant invasion process, both by creating disturbances that potentially favour non-native invasions and as a possible tool for controlling alien invasions. Havill et al. (Applied Vegetation Science, 18, 2015, this issue) determine how native and non-native species respond to different fire regimes as a first step in understanding the potential control of invasive grasses.

  20. Long-term exposure to elevated CO2 enhances plant community stability by suppressing dominant plant species in a mixed-grass prairie

    PubMed Central

    Zelikova, Tamara Jane; Blumenthal, Dana M.; Williams, David G.; Souza, Lara; LeCain, Daniel R.; Morgan, Jack; Pendall, Elise

    2014-01-01

    Climate controls vegetation distribution across the globe, and some vegetation types are more vulnerable to climate change, whereas others are more resistant. Because resistance and resilience can influence ecosystem stability and determine how communities and ecosystems respond to climate change, we need to evaluate the potential for resistance as we predict future ecosystem function. In a mixed-grass prairie in the northern Great Plains, we used a large field experiment to test the effects of elevated CO2, warming, and summer irrigation on plant community structure and productivity, linking changes in both to stability in plant community composition and biomass production. We show that the independent effects of CO2 and warming on community composition and productivity depend on interannual variation in precipitation and that the effects of elevated CO2 are not limited to water saving because they differ from those of irrigation. We also show that production in this mixed-grass prairie ecosystem is not only relatively resistant to interannual variation in precipitation, but also rendered more stable under elevated CO2 conditions. This increase in production stability is the result of altered community dominance patterns: Community evenness increases as dominant species decrease in biomass under elevated CO2. In many grasslands that serve as rangelands, the economic value of the ecosystem is largely dependent on plant community composition and the relative abundance of key forage species. Thus, our results have implications for how we manage native grasslands in the face of changing climate. PMID:25313034

  1. Long-term exposure to elevated CO2 enhances plant community stability by suppressing dominant plant species in a mixed-grass prairie

    NASA Astrophysics Data System (ADS)

    Zelikova, Tamara Jane; Blumenthal, Dana M.; Williams, David G.; Souza, Lara; LeCain, Daniel R.; Morgan, Jack; Pendall, Elise

    2014-10-01

    Climate controls vegetation distribution across the globe, and some vegetation types are more vulnerable to climate change, whereas others are more resistant. Because resistance and resilience can influence ecosystem stability and determine how communities and ecosystems respond to climate change, we need to evaluate the potential for resistance as we predict future ecosystem function. In a mixed-grass prairie in the northern Great Plains, we used a large field experiment to test the effects of elevated CO2, warming, and summer irrigation on plant community structure and productivity, linking changes in both to stability in plant community composition and biomass production. We show that the independent effects of CO2 and warming on community composition and productivity depend on interannual variation in precipitation and that the effects of elevated CO2 are not limited to water saving because they differ from those of irrigation. We also show that production in this mixed-grass prairie ecosystem is not only relatively resistant to interannual variation in precipitation, but also rendered more stable under elevated CO2 conditions. This increase in production stability is the result of altered community dominance patterns: Community evenness increases as dominant species decrease in biomass under elevated CO2. In many grasslands that serve as rangelands, the economic value of the ecosystem is largely dependent on plant community composition and the relative abundance of key forage species. Thus, our results have implications for how we manage native grasslands in the face of changing climate.

  2. Plant species richness at different scales in native and exotic grasslands in Southeastern Arizona

    USGS Publications Warehouse

    McLaughlin, S.P.; Bowers, Janice E.

    2006-01-01

    Species richness in Madrean mixed-grass prairies dominated by native or exotic species in southeastern Arizona was characterized at the community and point scales using ten 1-m2 quadrats nested within each of eight 1000-m2 plots. In the 1000-m2 plots average richness was significantly higher in oak savanna (OS, 121.0 species) than in exotic grassland on mesa tops (EMT, 52.0 species), whereas native grassland on mesa slopes (NMS, 92.5 species) and native grassland on mesa tops (NMT, 77.0 species) did not differ significantly in richness from OS or EMT When richness was partitioned by life form, EMT was notably poorer than other community types in species of perennial grasses, perennial herbs, and summer annuals. In the 1-m2 quadrats, OS (21.2 species), NMS (20.9 species), and NMT (20.7 species) were significantly richer than EMT (5.9 species). Cover in 1-m2 plots was significantly higher in EMT than in NMT, NMS, or OS. Species richness at the point scale showed a unimodal relation to canopy cover, with cover accounting for 30% of the variation in number of species in 1-m2 quadrats. Competitive exclusion and allelopathy have perhaps limited species richness at the point scale in exotic grassland. There was no evidence of a species-pool effect between point and community scales, but such an effect between community and landscape scales was supported. Madrean mixed-grass prairies are landscapes with high species richness in comparison to other grassland types in North America, providing a large pool of potential colonizing species at the community scale. Beta-diversity (between communities) within the landscape of the Appleton-Whittell Research Ranch was consequently high despite a relative lack of habitat diversity.

  3. Accumulation of seleno-amino acids in legume and grass plant species grown in selenium-laden soils

    SciTech Connect

    Wu, L.; Guo, X.; Banuelos, G.S.

    1997-03-01

    Seleno-amino acid accumulation was studied for two legume and two grass species grown in Selenium (Se)-laden soils. An antagonistic relationship was found between the tissue Se-amino acid concentration and the corresponding sulfur-amino acid concentration. This relationship demonstrates a competitive interaction between Se and sulfate at the amino acid synthesis level. The nonsulfur-containing amino acids were not substantially affected by the increase of tissue Se concentration. Sour clover (Melilotus indica L.) was able to accumulate much greater tissue Se concentration than the other three species. Tissue methionine concentration of sour clover, rabbitfoot grass (Polypogon monspeliensis L.), and tall fescue (Festuca arundinacea Schreb.) was not significantly affected by the increase of tissue selenomethionine concentration, but a highly significant negative correlation was found in alfalfa (Medicago sativa L.). This discrepancy suggests that a less antagonistic effect on sulfur-amino acids under the increase of Se-amino acid analogues in the tissue might be able to minimize Se toxicity to the plant. Both Se-methylselenocysteine (nonprotein amino acid) and selenomethionine (protein amino acid) accumulated in the plants when grown in Se-laden soils. Possible effects of these Se-amino acids accumulated by plants on animal health should be tested before the plants are used for forage supplementation.

  4. Placentation in different mammalian species.

    PubMed

    Chavatte-Palmer, Pascale; Tarrade, Anne

    2016-06-01

    The placenta is a complex, transient organ associated with viviparity, which is located at the interface of the dam and fetus during pregnancy. It is formed after attachment, or implantation, of the blastocyst on the uterine lining and derives from complex cellular and molecular interactions between uterine and embryonic tissues. In mammals, there are many forms of placentation but this organ has the same function in all species: it is responsible for orchestrating materno-fetal exchanges, together with endocrine and immunological functions. PMID:27155775

  5. Genome size differences in Hyalella cryptic species.

    PubMed

    Vergilino, Roland; Dionne, Kaven; Nozais, Christian; Dufresne, France; Belzile, Claude

    2012-02-01

    The Hyalella azteca (Saussure) complex includes numerous amphipod cryptic species in freshwater habitats in America as revealed by DNA barcoding surveys. Two ecomorphs (small and large) have evolved numerous times in this complex. Few phenotypic criteria have been found to differentiate between the numerous species of this complex. The present study aims to explore genome size differences between some species of the H. azteca complex co-occurring in a Canadian boreal lake using flow cytometry. Nuclear DNA content was estimated for 50 individuals belonging to six COI haplotypes corresponding to four provisional species of the H. azteca complex. Species from the large ecomorph had C-values significantly larger than species from the small ecomorph, whereas slight differences were found among species of the small ecomorph. These differences in genome sizes might be linked to ecological and physiological differences among species of the H. azteca complex. PMID:22263854

  6. DNA barcoding discriminates a new cryptic grass species revealed in an ethnobotany study by the hill tribes of the Western Ghats in southern India.

    PubMed

    Ragupathy, Subramanyam; Newmaster, Steven G; Murugesan, Maruthakkutti; Balasubramaniam, Velusamy

    2009-05-01

    Our research brought together traditional aboriginal knowledge (TK) and scientific knowledge (SK) to explore the relationship between scientific and aboriginal systems of botanical classification and the corresponding valorization(s) of biological diversity in the Western Ghats of southern India. We worked with two aboriginal cultures namely 'Irulas' and 'Malasars' of the Nilgiri Biosphere Reserve with an objective of evaluating the ability of different knowledge systems (SK and TK) to distinguish grass species belonging to the genus Tripogon, and assess the ability of DNA barcoding to discriminate a new cryptic species 'Tripogon cope' as deciphered by the hill tribes. We discovered that the aboriginal informants identified a common ethnotaxa 'Sunai pul', which is a cryptic species of grass not recognized by the SK classification.'sunai pul' is very important to both aboriginal cultures with ritualistic and economic utility. Morphometric analysis confirms the cryptic nature of this new species, which was validated using DNA barcoding. DNA barcode regions matK and trnH-psbA showed distinct sequence variations among the closely related ethnotaxa. Given the cryptic nature of ethnotaxa, we propose that a DNA barcode may be a reliable tool to identify ethnotaxa. We have initiated further studies in other cultures to develop theoretically sophisticated insights concerning the encounter between 'local' and 'scientific' approaches to the use of biodiversity knowledge. Furthermore, the research will add to a unifying global effort to speed up the documentation and understanding of the planet's natural diversity, while simultaneously respecting the cultural heterogeneity as a vital component of biological diversity. PMID:21564975

  7. Genetic diversity and structure of Neotyphodium species and their host Achnatherum sibiricum in a natural grass-endophyte system.

    PubMed

    Zhang, Xin; Ren, Anzhi; Ci, Huacong; Gao, Yubao

    2010-05-01

    Achnatherum sibiricum (Poaceae) is a perennial bunchgrass native to the Inner Mongolia Steppe of China. This grass is commonly infected by epichloë endophytes with high-infection frequencies. Previously, we identified two predominant Neotyphodium spp., N. sibiricum and N. gansuense. In the present study, genetic diversity and structure were analyzed for the two predominant Neotyphodium spp. as well as the host grass. We obtained 103 fungal isolates from five populations; 33 were identified as N. sibiricum and 61 as N. gansuense. All populations hosted both endophytic species, but genetic variation was much higher for N. gansuense than for N. sibiricum. The majority of fungal isolates were haploid, and 13% of them were heterozygous at one SSR locus, suggesting hybrid origins of those isolates. Significant linkage disequilibrium of fungal SSR loci suggested that both fungal species primarily propagate by clonal growth through plant seeds, whereas variation in genetic diversity and the presence of hybrids in both endophytic species revealed that although clonal propagation was prevalent, occasional recombination might also occur. By comparing genetic differentiation among populations, we found around 4-7-fold greater differentiation of endophyte populations than host populations, implying more restricted gene flow of endophytes than hosts. We proposed that endophyte infection of A. sibiricum might confer the host some selective advantages under certain conditions, which could help to maintain high-endophyte-infection frequencies in host populations, even when their gene flows do not match each other. Furthermore, we suggested that the same genotype of endophyte as well as host should be confirmed if the objective of the study is to know the influence of endophyte or host genotype on their symbiotic relationship, instead of just considering whether the plant is infected by an endophyte or not, since endophytes from the same host species could exhibit high levels of

  8. Functional Traits Differ between Cereal Crop Progenitors and Other Wild Grasses Gathered in the Neolithic Fertile Crescent

    PubMed Central

    Cunniff, Jennifer; Wilkinson, Sarah; Charles, Michael; Jones, Glynis; Rees, Mark; Osborne, Colin P.

    2014-01-01

    The reasons why some plant species were selected as crops and others were abandoned during the Neolithic emergence of agriculture are poorly understood. We tested the hypothesis that the traits of Fertile Crescent crop progenitors were advantageous in the fertile, disturbed habitats surrounding early settlements and in cultivated fields. We screened functional traits related to competition and disturbance in a group of grass species that were increasingly exploited by early plant gatherers, and that were later domesticated (crop progenitors); and in a set of grass species for which there is archaeological evidence of gathering, but which were never domesticated (wild species). We hypothesised that crop progenitors would have greater seed mass, growth rate, height and yield than wild species, as these traits are indicative of greater competitive ability, and that crop progenitors would be more resilient to defoliation. Our results show that crop progenitors have larger seed mass than wild species, germinate faster and have greater seedling size. Increased seed size is weakly but positively correlated with a higher growth rate, which is primarily driven by greater biomass assimilation per unit leaf area. Crop progenitors also tend to have a taller stature, greater grain yield and higher resilience to defoliation. Collectively, the data are consistent with the hypothesis that adaptations to competition and disturbance gave crop progenitors a selective advantage in the areas surrounding early human settlements and in cultivated environments, leading to their adoption as crops through processes of unconscious selection. PMID:24489941

  9. In the shadow of a megalopolis, a new Flexamia from a threatened grass species in the New Jersey Pine Barrens (Hemiptera, Cicadellidae, Deltocephalinae, Paralimnini).

    PubMed

    Hicks, Andrew

    2015-01-01

    A previously unknown species of the North American leafhopper genus Flexamia, Flexamiawhitcombi sp. n., is described from pinebarren smokegrass (Muhlenbergiatorreyana (Schult.) Hitchc.), a state-listed threatened grass in the New Jersey Pine Barrens. The serrata species group, to which it belongs, is redefined and a key to the species of the group is provided. This is the first reported insect association with Muhlenbergiatorreyana. PMID:26257551

  10. In the shadow of a megalopolis, a new Flexamia from a threatened grass species in the New Jersey Pine Barrens (Hemiptera, Cicadellidae, Deltocephalinae, Paralimnini)

    PubMed Central

    Hicks, Andrew

    2015-01-01

    Abstract A previously unknown species of the North American leafhopper genus Flexamia, Flexamia whitcombi sp. n., is described from pinebarren smokegrass (Muhlenbergia torreyana (Schult.) Hitchc.), a state-listed threatened grass in the New Jersey Pine Barrens. The serrata species group, to which it belongs, is redefined and a key to the species of the group is provided. This is the first reported insect association with Muhlenbergia torreyana. PMID:26257551

  11. The effects of seed ingestion by livestock, dung fertilization, trampling, grass competition and fire on seedling establishment of two woody plant species.

    PubMed

    Tjelele, Julius; Ward, David; Dziba, Luthando

    2015-01-01

    The increasing rate of woody plant encroachment in grasslands or savannas remains a challenge to livestock farmers. The causes and control measures of woody plant encroachment are of common interest, especially where it negatively affects the objectives of an agricultural enterprise. The objectives of this study were to determine the effects of gut passage (goats, cattle), dung (nutrients), fire, grass competition and trampling on establishment of A. nilotica and D. cinerea seedlings. Germination trials were subjected to the following treatments: 1) seed passage through the gut of cattle and goats and unpassed/ untreated seeds (i.e. not ingested), 2) dung and control (no dung), 3) grass and control (mowed grass), 4) fire and control (no fire), 5) trampling and control (no trampling). The interaction of animal species, grass and fire had an effect on seedling recruitment (P < 0.0052). Seeds retrieved from goats and planted with no grass and with fire (6.81% ± 0.33) had a significant effect on seedling recruitment than seeds retrieved from goats and planted with grass and no fire (2.98% ± 0.33). Significantly more D. cinerea and A. nilotica seeds germinated following seed ingestion by goats (3.59% ± 0.16) than cattle (1.93% ± 0.09) and control or untreated seeds (1.69% ± 0.11). Less dense grass cover, which resulted in reduced grass competition with tree seedlings for light, space and water, and improved seed scarification due to gut passage were vital for emergence and recruitment of Acacia seedlings. These results will contribute considerably to the understanding of the recruitment phase of woody plant encroachment. PMID:25695765

  12. Loss of native herbaceous species due to woody plant encroachment facilitates the establishment of an invasive grass.

    PubMed

    Alofs, Karen M; Fowler, Norma L

    2013-03-01

    Although negative relationships between diversity (frequently measured as species richness) and invasibility at neighborhood or community scales have often been reported, realistic natural diversity gradients have rarely been studied at this scale. We recreated a naturally occurring gradient in species richness to test the effects of species richness on community invasibility. In central Texas savannas, as the proportion of woody plants increases (a process known as woody plant encroachment), herbaceous habitat is both lost and fragmented, and native herbaceous species richness declines. We examined the effects of these species losses on invasibility in situ by removing species that occur less frequently in herbaceous patches as woody plant encroachment advances. This realistic species removal was accompanied by a parallel and equivalent removal of biomass with no changes in species richness. Over two springs, the nonnative bunchgrass Bothriochloa ischaemum germinated significantly more often in the biomass-removal treatment than in unmanipulated control plots, suggesting an effect of native plant density independent of diversity. Additionally, significantly more germination occurred in the species-removal treatment than in the biomass-removal treatment. Changes in species richness had a stronger effect on B. ischaemum germination than changes in plant density, demonstrating that niche-related processes contributed more to biotic resistance in this system than did species-neutral competitive interactions. Similar treatment effects were found on transplant growth. Thus we show that woody plant encroachment indirectly facilitates the establishment of an invasive grass by reducing native diversity. Although we found a negative relationship between species richness and invasibility at the scale of plots with similar composition and environmental conditions, we found a positive relationship between species richness and invasibility at larger scales. This apparent

  13. Cellulosic ethanol production from warm-season perennial grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Warm-season (C4) perennial grasses are able to produce large quantities of biomass, and will play a key role in bioenergy production, particularly in areas with long warm growing seasons. Several different grass species have been studied as candidate bioenergy crops for the Southeast USA, and each ...

  14. Genome-Wide Analysis of NBS-LRR Genes in Sorghum Genome Revealed Several Events Contributing to NBS-LRR Gene Evolution in Grass Species

    PubMed Central

    Yang, Xiping; Wang, Jianping

    2016-01-01

    The nucleotide-binding site (NBS)–leucine-rich repeat (LRR) gene family is crucially important for offering resistance to pathogens. To explore evolutionary conservation and variability of NBS-LRR genes across grass species, we identified 88, 107, 24, and 44 full-length NBS-LRR genes in sorghum, rice, maize, and Brachypodium, respectively. A comprehensive analysis was performed on classification, genome organization, evolution, expression, and regulation of these NBS-LRR genes using sorghum as a representative of grass species. In general, the full-length NBS-LRR genes are highly clustered and duplicated in sorghum genome mainly due to local duplications. NBS-LRR genes have basal expression levels and are highly potentially targeted by miRNA. The number of NBS-LRR genes in the four grass species is positively correlated with the gene clustering rate. The results provided a valuable genomic resource and insights for functional and evolutionary studies of NBS-LRR genes in grass species. PMID:26792976

  15. Root Antioxidant Mechanisms in Relation to Root Thermotolerance in Perennial Grass Species Contrasting in Heat Tolerance.

    PubMed

    Xu, Yi; Burgess, Patrick; Huang, Bingru

    2015-01-01

    Mechanisms of plant root tolerance to high temperatures through antioxidant defense are not well understood. The objective of this study was to investigate whether superior root thermotolerance of heat-tolerant Agrostis scabra relative to its congeneric heat-sensitive Agrostis stolonifera was associated with differential accumulation of reactive oxygen species and antioxidant scavenging systems. A. scabra 'NTAS' and A. stolonifera 'Penncross' plants were exposed to heat stress (35/30°C, day/night) in growth chambers for 24 d. Superoxide (O2(-)) content increased in both A. stolonifera and A. scabra roots under heat stress but to a far lesser extent in A. scabra than in A. stolonifera. Hydrogen peroxide (H2O2) content increased significantly in A. stolonifera roots but not in A. scabra roots responding to heat stress. The content of antioxidant compounds (ascorbate and glutathione) did not differ between A. stolonifera and A. scabra under heat stress. Enzymatic activity of superoxide dismutase was less suppressed in A. scabra than that in A. stolonifera under heat stress, while peroxidase and catalase were more induced in A. scabra than in A. stolonifera. Similarly, their encoded transcript levels were either less suppressed, or more induced in A. scabra roots than those in A. stolonifera during heat stress. Roots of A. scabra exhibited greater alternative respiration rate and lower cytochrome respiration rate under heat stress, which was associated with suppression of O2(-) and H2O2 production as shown by respiration inhibitors. Superior root thermotolerance of A. scabra was related to decreases in H2O2 and O2(-) accumulation facilitated by active enzymatic antioxidant defense systems and the maintenance of alternative respiration, alleviating cellular damages by heat-induced oxidative stress. PMID:26382960

  16. Root Antioxidant Mechanisms in Relation to Root Thermotolerance in Perennial Grass Species Contrasting in Heat Tolerance

    PubMed Central

    Xu, Yi; Burgess, Patrick; Huang, Bingru

    2015-01-01

    Mechanisms of plant root tolerance to high temperatures through antioxidant defense are not well understood. The objective of this study was to investigate whether superior root thermotolerance of heat-tolerant Agrostis scabra relative to its congeneric heat-sensitive Agrostis stolonifera was associated with differential accumulation of reactive oxygen species and antioxidant scavenging systems. A. scabra ‘NTAS’ and A. stolonifera ‘Penncross’ plants were exposed to heat stress (35/30°C, day/night) in growth chambers for 24 d. Superoxide (O2-) content increased in both A. stolonifera and A. scabra roots under heat stress but to a far lesser extent in A. scabra than in A. stolonifera. Hydrogen peroxide (H2O2) content increased significantly in A. stolonifera roots but not in A. scabra roots responding to heat stress. The content of antioxidant compounds (ascorbate and glutathione) did not differ between A. stolonifera and A. scabra under heat stress. Enzymatic activity of superoxide dismutase was less suppressed in A. scabra than that in A. stolonifera under heat stress, while peroxidase and catalase were more induced in A. scabra than in A. stolonifera. Similarly, their encoded transcript levels were either less suppressed, or more induced in A. scabra roots than those in A. stolonifera during heat stress. Roots of A. scabra exhibited greater alternative respiration rate and lower cytochrome respiration rate under heat stress, which was associated with suppression of O2- and H2O2 production as shown by respiration inhibitors. Superior root thermotolerance of A. scabra was related to decreases in H2O2 and O2- accumulation facilitated by active enzymatic antioxidant defense systems and the maintenance of alternative respiration, alleviating cellular damages by heat-induced oxidative stress. PMID:26382960

  17. Testing the mechanisms of diversity-dependent overyielding in a grass species.

    PubMed

    Atwater, Daniel Z; Callaway, Ragan M

    2015-12-01

    Plant diversity enhances many ecosystem processes, including productivity, but these effects have been studied almost exclusively at the taxonomic scale of species. We explore the effect of intraspecific diversity on the productivity of a widespread and dominant grassland species using accessions collected from populations throughout its range. We found that increasing population/ecotype diversity of Pseudoroegneria spicata increased productivity to a similar degree as that reported for species diversity. However, we did not find evidence that overyielding was related to either resource depletion or to pathogenic soil fungi, two causes of overyielding in species-diverse communities. Instead, larger accessions overyielded at low diversity at the expense of smaller accessions, and small accessions overyielded through complementarity at all levels of diversity. Furthermore, overyielding was stronger for accessions from mesic environments, suggesting that local adaptation might predictably influence how plants respond to increases in diversity. This suggests that mass-based competition or other cryptic accession-specific processes had complex but important effects on overyielding. Our results indicate that the effects of diversity within a species can be substantial but that overyielding by intraspecifically diverse populations may not be through the same processes thought to cause overyielding in species diverse communities. PMID:26909438

  18. Are Mojave Desert annual species equal? Resource acquisition and allocation for the invasive grass Bromus madritensis subsp. rubens (Poaceae) and two native species

    USGS Publications Warehouse

    DeFalco, L.A.; Bryla, D.R.; Smith-Longozo, V.; Nowak, R.S.

    2003-01-01

    Abundance of invasive plants is often attributed to their ability ot outcompete native species. We compared resource acquisition and allocation of the invasive annual grass Bromus madritensis subsp. rubens with that of two native Mojave Desert annuals, Vulpia octoflora and Descurainia pinnata, in a glasshouse experiment. Each species was grown in monoculture at two densities and two levels of N availability to compare how these annuals capture resources and to understand their relative sensitivities to environmental change. During >4 mo of growth, Bromus used water more rapidly and had greater biomass and N content than the natives, partly because of its greater root-surface area and its exploitation of deep soils. Bromus also had greater N uptake, net assimilation and transpiration rates, and canopy area than Vulpia. Resource use by Bromus was less sensitive to changes in N availability or density than were the natives. The two native species in this study produced numerous small seeds that tended to remain dormant, thus ensuring escape of offspring from unfavorable germination conditions; Bromus produced fewer but larger seeds that readily germinated. Collectively, these traits give Bromus the potential to rapidly establish in diverse habitats of the Mojave Desert, thereby gaining an advantage over coexisting native species.

  19. Fusarium dactylidis sp. nov., a novel nivalenol toxin-producing species sister to F. pseudograminearum isolated from orchard grass (Dactylis glomerata) in Oregon and New Zealand.

    PubMed

    Aoki, Takayuki; Vaughan, Martha M; McCormick, Susan P; Busman, Mark; Ward, Todd J; Kelly, Amy; O'Donnell, Kerry; Johnston, Peter R; Geiser, David M

    2015-01-01

    The B trichothecene toxin-producing clade (B clade) of Fusarium includes the etiological agents of Fusarium head blight, crown rot of wheat and barley and stem and ear rot of maize. B clade isolates also have been recovered from several wild and cultivated grasses, including Dactylis glomerata (orchard grass or cock's foot), one of the world's most important forage grasses. Two isolates from the latter host are formally described here as F. dactylidis. Phenotypically F. dactylidis most closely resembles F. ussurianum from the Russian Far East. Both species produce symmetrical sporodochial conidia that are similar in size and curved toward both ends. However, conidia of F. ussurianum typically end in a narrow apical beak while the apical cell of F. dactylidis is acute. Fusarium dactylidis produced nivalenol mycotoxin in planta as well as low but detectable amounts of the estrogenic mycotoxin zearalenone in vitro. Results of a pathogenicity test revealed that F. dactylidis induced mild head blight on wheat. PMID:25550300

  20. Untangling a species complex of arid zone grasses (Triodia) reveals patterns congruent with co-occurring animals.

    PubMed

    Anderson, Benjamin M; Barrett, Matthew D; Krauss, Siegfried L; Thiele, Kevin

    2016-08-01

    The vast Australian arid zone formed over the last 15million years, and gradual aridification as well as more extreme Pliocene and Pleistocene climate shifts have impacted the evolution of its biota. Understanding the evolutionary history of groups of organisms or regional biotas such as the Australian arid biota requires clear delimitation of the units of biodiversity (taxa). Here we integrate evidence from nuclear (ETS and ITS) and chloroplast (rps16-trnK spacer) regions and morphology to clarify taxonomic boundaries in a species complex of Australian hummock grasses (Triodia) to better understand the evolution of Australian arid zone plants and to evaluate congruence in distribution patterns with co-occurring organisms. We find evidence for multiple new taxa in the T. basedowii species complex, but also incongruence between data sets and indications of hybridization that complicate delimitation. We find that the T. basedowii complex has high lineage diversity and endemism in the biologically important Pilbara region of Western Australia, consistent with the region acting as a refugium. Taxa show strong geographic structure in the Pilbara, congruent with recent work on co-occurring animals and suggesting common evolutionary drivers across the biota. Our findings confirm recognition of the Pilbara as an important centre of biodiversity in the Australian arid zone, and provide a basis for future taxonomic revision of the T. basedowii complex and more detailed study of its evolutionary history and that of arid Australia. PMID:27179699

  1. Identifying biochemical phenotypic differences between cryptic species

    PubMed Central

    Liebeke, Manuel; Bruford, Michael W.; Donnelly, Robert K.; Ebbels, Timothy M. D.; Hao, Jie; Kille, Peter; Lahive, Elma; Madison, Rachael M.; Morgan, A. John; Pinto-Juma, Gabriela A.; Spurgeon, David J.; Svendsen, Claus; Bundy, Jacob G.

    2014-01-01

    Molecular genetic methods can distinguish divergent evolutionary lineages in what previously appeared to be single species, but it is not always clear what functional differences exist between such cryptic species. We used a metabolomic approach to profile biochemical phenotype (metabotype) differences between two putative cryptic species of the earthworm Lumbricus rubellus. There were no straightforward metabolite biomarkers of lineage, i.e. no metabolites that were always at higher concentration in one lineage. Multivariate methods, however, identified a small number of metabolites that together helped distinguish the lineages, including uncommon metabolites such as Nε-trimethyllysine, which is not usually found at high concentrations. This approach could be useful for characterizing functional trait differences, especially as it is applicable to essentially any species group, irrespective of its genome sequencing status. PMID:25252836

  2. Differences in drought sensitivities and photosynthetic limitations between co-occurring C3 and C4 (NADP-ME) Panicoid grasses

    PubMed Central

    Ripley, Brad; Frole, Kristen; Gilbert, Matthew

    2010-01-01

    Background and Aims The success of C4 plants lies in their ability to attain greater efficiencies of light, water and nitrogen use under high temperature, providing an advantage in arid, hot environments. However, C4 grasses are not necessarily less sensitive to drought than C3 grasses and are proposed to respond with greater metabolic limitations, while the C3 response is predominantly stomatal. The aims of this study were to compare the drought and recovery responses of co-occurring C3 and C4 NADP-ME grasses from the subfamily Panicoideae and to determine stomatal and metabolic contributions to the observed response. Methods Six species of locally co-occurring grasses, C3 species Alloteropsis semialata subsp. eckloniana, Panicum aequinerve and Panicum ecklonii, and C4 (NADP-ME) species Heteropogon contortus, Themeda triandra and Tristachya leucothrix, were established in pots then subjected to a controlled drought followed by re-watering. Water potentials, leaf gas exchange and the response of photosynthetic rate to internal CO2 concentrations were determined on selected occasions during the drought and re-watering treatments and compared between species and photosynthetic types. Key Results Leaves of C4 species of grasses maintained their photosynthetic advantage until water deficits became severe, but lost their water-use advantage even under conditions of mild drought. Declining C4 photosynthesis with water deficit was mainly a consequence of metabolic limitations to CO2 assimilation, whereas, in the C3 species, stomatal limitations had a prevailing role in the drought-induced decrease in photosynthesis. The drought-sensitive metabolism of the C4 plants could explain the observed slower recovery of photosynthesis on re-watering, in comparison with C3 plants which recovered a greater proportion of photosynthesis through increased stomatal conductance. Conclusions Within the Panicoid grasses, C4 (NADP-ME) species are metabolically more sensitive to drought than

  3. CO2 enrichment increases element concentrations in grass mixtures by changing species abundances

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The continuing rise in atmospheric carbon dioxide (CO2) concentration may increase plant growth relatively more than the uptake of soil-derived chemical elements that are essential for herbivores. Rising CO2 also may alter the nutritional quality of forage or fodder derived from multi-species veget...

  4. Quantitative Analysis of Plant Consumption and Preference by Oedaleus asiaticus (Acrididae: Oedipodinae) in Changed Plant Communities Consisting of Three Grass Species.

    PubMed

    Huang, X; McNeill, M; Zhang, Z

    2016-02-01

    We used Oedaleus asiaticus Bey-Bienko (Acrididae: Oedipodinae) as a model species to examine how plant community composition influenced grasshopper population densities and feeding habits. Our results show that in the Xinli Gol Grassland ecosystem, both plant community composition and grasshopper density vary considerably over fairly small distances, and that O. asiaticus density was directly related to the proportional abundance of specific plant species. A 60-d field-cage study showed that O. asiaticus food preference and consumption differed when the ratios of three dominant grass species (Leymus chinensis (Trin.) Tzvel, Stipa krylovii Roshev, and Cleistogenes squarrosa (Trin.) Keng) differed. The consumption of both S. krylovii and C. squarrosa increased with a corresponding increase in their respective biomass availability. Although O. asiaticus preferred S. krylovii and ate only small amounts of L. chinensis, a specific amount of L. chinensis was always consumed. Feeding of these three plant species could be divided into three levels based on diet selectivity index (SI), with O. asiaticus showing a strong preference for S. krylovii (SI > 1), over that for C. squarrosa (0.5 < SI ≤ 1), and a low acceptance for L. chinensis (0 < SI ≤ 0.5). Plant consumption and preference by O. asiaticus was in decreasing order S. krylovii>C. squarrosa>L. chinensis. This study shows that small-scale changes in plant community composition can have large affects on grasshopper diets and populations. As such, this study is useful for developing guidelines for the monitoring of O. asiaticus impacts against the background of vegetation succession and changing plant communities in response to grazing or human activities. PMID:26577863

  5. Grass allergy

    MedlinePlus

    Although the grass itself may not be harmful, fertilizers, insecticides , and herbicides applied to the grass can ... with a chemical of any sort such as fertilizer, insecticide, or herbicide, find out the product name ...

  6. Rapidly evolving R genes in diverse grass species confer resistance to rice blast disease

    PubMed Central

    Yang, Sihai; Li, Jing; Zhang, Xiaohui; Zhang, Qijun; Huang, Ju; Chen, Jian-Qun; Hartl, Daniel L.; Tian, Dacheng

    2013-01-01

    We show that the genomes of maize, sorghum, and brachypodium contain genes that, when transformed into rice, confer resistance to rice blast disease. The genes are resistance genes (R genes) that encode proteins with nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains (NBS–LRR proteins). By using criteria associated with rapid molecular evolution, we identified three rapidly evolving R-gene families in these species as well as in rice, and transformed a randomly chosen subset of these genes into rice strains known to be sensitive to rice blast disease caused by the fungus Magnaporthe oryzae. The transformed strains were then tested for sensitivity or resistance to 12 diverse strains of M. oryzae. A total of 15 functional blast R genes were identified among 60 NBS–LRR genes cloned from maize, sorghum, and brachypodium; and 13 blast R genes were obtained from 20 NBS–LRR paralogs in rice. These results show that abundant blast R genes occur not only within species but also among species, and that the R genes in the same rapidly evolving gene family can exhibit an effector response that confers resistance to rapidly evolving fungal pathogens. Neither conventional evolutionary conservation nor conventional evolutionary convergence supplies a satisfactory explanation of our findings. We suggest a unique mechanism termed “constrained divergence,” in which R genes and pathogen effectors can follow only limited evolutionary pathways to increase fitness. Our results open avenues for R-gene identification that will help to elucidate R-gene vs. effector mechanisms and may yield new sources of durable pathogen resistance. PMID:24145399

  7. Grass Lignocellulose

    NASA Astrophysics Data System (ADS)

    Akin, Danny E.

    Grass lignocelluloses are limited in bioconversion by aromatic constituents, which include both lignins and phenolic acids esters. Histochemistry, ultraviolet absorption microspectrophotometry, and response to microorganisms and specific enzymes have been used to determine the significance of aromatics toward recalcitrance. Coniferyl lignin appears to be the most effective limitation to biodegradation, existing in xylem cells of vascular tissues; cell walls with syringyl lignin, for example, leaf sclerenchyma, are less recalcitrant. Esterified phenolic acids, i.e., ferulic and p-coumaric acids, often constitute a major chemical limitation in nonlignified cell walls to biodegradation in grasses, especially warm-season species. Methods to improve biodegradability through modification of aromatics include: plant breeding, use of lignin-degrading white-rot fungi, and addition of esterases. Plant breeding for new cultivars has been especially effective for nutritionally improved forages, for example, bermudagrasses. In laboratory studies, selective white-rot fungi that lack cellulases delignified the lignocellulosic materials and improved fermentation of residual carbohydrates. Phenolic acid esterases released p-coumaric and ferulic acids for potential coproducts, improved the available sugars for fermentation, and improved biodegradation. The separation and removal of the aromatic components for coproducts, while enhancing the availability of sugars for bioconversion, could improve the economics of bioconversion.

  8. Comparative Proteomic Analysis of the Stolon Cold Stress Response between the C4 Perennial Grass Species Zoysia japonica and Zoysia metrella

    PubMed Central

    Xuan, Jiping; Song, Yufeng; Zhang, Hongxiao; Liu, Jianxiu; Guo, Zhongren; Hua, Yuelou

    2013-01-01

    Zoysiagrass, the most cold-tolerant grass among the warm-season turfgrasses, is often used as a model species for isolating cellular components related to cold stress. To understand the proteomic responses to cold stress in zoysiagrass stolons, we extracted stolon proteins from Zoysiajaponica, cv. Meyer (cold-tolerant) and Z. metrella, cv. Diamond (cold-sensitive), which were grown with or without cold treatment. Approximately 700 proteins were resolved on 2-DE gels, and 70 protein spots were differentially accumulated. We further observed that 45 of the identified proteins participate in 10 metabolic pathways and cellular processes. A significantly greater number of proteins accumulated in the Meyer than in the Diamond and 15 increased proteins were detected only in the Meyer cultivar under cold stress. Furthermore, we propose a cold stress-responsive protein network composed of several different functional components that exhibits a balance between reactive oxygen species (ROS) production and scavenging, accelerated protein biosynthesis and proteolysis, reduced protein folding, enhanced photosynthesis, abundant energy supply and enhanced biosynthesis of carbohydrates and nucleotides. Generally, the cold-tolerant Meyer cultivar showed a greater ROS scavenging ability, more abundant energy supply and increased photosynthesis and protein synthesis than did the cold-sensitive Diamond cultivar, which may partly explain why Meyer is more cold tolerant. PMID:24086619

  9. Grass species influence on plant N uptake - Determination of atmospheric N deposition to a semi-natural peat bog site using a 15N labelling approach

    NASA Astrophysics Data System (ADS)

    Hurkuck, Miriam; Brümmer, Christian; Spott, Oliver; Flessa, Heinz; Kutsch, Werner L.

    2014-05-01

    Large areas of natural peat bogs in Northwestern Germany have been converted to arable land and were subjected to draining and peat cutting in the past. The few protected peatland areas remaining are affected by high nitrogen (N) deposition. Our study site - a moderately drained raised bog - is surrounded by highly fertilized agricultural land and livestock production. In this study, we used a 15N pool dilution technique called 'Integrated Total Nitrogen Input' (ITNI) to quantify annual deposition of atmospheric N into biomonitoring pots over a two-year period. Since it considers direct N uptake by plants, it was expected to result in higher N input than conventional methods for determination of N deposition (e.g. micrometeorological approaches, bulk N samplers). Using Lolium multiflorum and Eriophorum vaginatum as monitor plants and low, medium and high levels of fertilization, we aimed to simulate increasing N deposition to planted pots and to allocate airborne N after its uptake by the soil-plant system in aboveground biomass, roots and soil. Increasing N fertilization was positively correlated with biomass production of Eriophorum vaginatum, whereas atmospheric plant N uptake decreased and highest airborne N input of 899.8 ± 67.4 µg N d-1 pot-1 was found for low N fertilization. In contrast, Lolium multiflorum showed a clear dependency of N supply on plant N uptake and was highest (688.7 ± 41.4 µg N d-1 pot-1) for highly fertilized vegetation pots. Our results suggest that grass species respond differently to increasing N input. While crop grasses such as Lolium multiflorum take up N according to N availability, species adopted to nutrient-limited conditions like Eriophorum vaginatum show N saturation effects with increasing N supply. Total airborne N input ranged from about 24 to 66 kg N ha-1 yr-1 dependent on the used indicator plant and the amount of added fertilizer. Parallel determination of atmospheric N deposition using a micrometeorological approach

  10. The importance of rare species: a trait-based assessment of rare species contributions to functional diversity and possible ecosystem function in tall-grass prairies

    PubMed Central

    Jain, Meha; Flynn, Dan FB; Prager, Case M; Hart, Georgia M; DeVan, Caroline M; Ahrestani, Farshid S; Palmer, Matthew I; Bunker, Daniel E; Knops, Johannes MH; Jouseau, Claire F; Naeem, Shahid

    2014-01-01

    The majority of species in ecosystems are rare, but the ecosystem consequences of losing rare species are poorly known. To understand how rare species may influence ecosystem functioning, this study quantifies the contribution of species based on their relative level of rarity to community functional diversity using a trait-based approach. Given that rarity can be defined in several different ways, we use four different definitions of rarity: abundance (mean and maximum), geographic range, and habitat specificity. We find that rarer species contribute to functional diversity when rarity is defined by maximum abundance, geographic range, and habitat specificity. However, rarer species are functionally redundant when rarity is defined by mean abundance. Furthermore, when using abundance-weighted analyses, we find that rare species typically contribute significantly less to functional diversity than common species due to their low abundances. These results suggest that rare species have the potential to play an important role in ecosystem functioning, either by offering novel contributions to functional diversity or via functional redundancy depending on how rare species are defined. Yet, these contributions are likely to be greatest if the abundance of rare species increases due to environmental change. We argue that given the paucity of data on rare species, understanding the contribution of rare species to community functional diversity is an important first step to understanding the potential role of rare species in ecosystem functioning. PMID:24455165

  11. The importance of rare species: a trait-based assessment of rare species contributions to functional diversity and possible ecosystem function in tall-grass prairies.

    PubMed

    Jain, Meha; Flynn, Dan Fb; Prager, Case M; Hart, Georgia M; Devan, Caroline M; Ahrestani, Farshid S; Palmer, Matthew I; Bunker, Daniel E; Knops, Johannes Mh; Jouseau, Claire F; Naeem, Shahid

    2014-01-01

    The majority of species in ecosystems are rare, but the ecosystem consequences of losing rare species are poorly known. To understand how rare species may influence ecosystem functioning, this study quantifies the contribution of species based on their relative level of rarity to community functional diversity using a trait-based approach. Given that rarity can be defined in several different ways, we use four different definitions of rarity: abundance (mean and maximum), geographic range, and habitat specificity. We find that rarer species contribute to functional diversity when rarity is defined by maximum abundance, geographic range, and habitat specificity. However, rarer species are functionally redundant when rarity is defined by mean abundance. Furthermore, when using abundance-weighted analyses, we find that rare species typically contribute significantly less to functional diversity than common species due to their low abundances. These results suggest that rare species have the potential to play an important role in ecosystem functioning, either by offering novel contributions to functional diversity or via functional redundancy depending on how rare species are defined. Yet, these contributions are likely to be greatest if the abundance of rare species increases due to environmental change. We argue that given the paucity of data on rare species, understanding the contribution of rare species to community functional diversity is an important first step to understanding the potential role of rare species in ecosystem functioning. PMID:24455165

  12. The effect of glyphosate on the growth and competitive effect of perennial grass species in semi-natural grasslands.

    PubMed

    Damgaard, Christian; Strandberg, Beate; Mathiassen, Solvejg K; Kudsk, Per

    2014-01-01

    Biodiversity within European semi-natural biotopes in agro-ecosystem is declining, and herbicide drift from neighbouring fields is considered as an important factor for the decline. The aim of the present study was to investigate whether the growth and competitive interactions in a model system of two perennial grass species, Festuca ovina and Agrostis capillaris, are affected by sub-lethal doses of glyphosate in field margins. In a glasshouse experiment with ample nitrogen, the interspecific competitive interactions were found to be significantly affected by glyphosate; the competitive effect of F. ovina on A. capillaris increased and the competitive effect of A. capillaris on F. ovina decreased with increasing doses of glyphosate. Furthermore, the importance of interspecific competition increased with the glyphosate dose. The results of the study of competitive interactions are in agreement with the observed plant community dynamics at the field site where F. ovina was found to be more dominant in plots treated with a relatively high dose of glyphosate. Importantly, the effects of glyphosate on the plant community dynamics critically depended on the effect of glyphosate on the plant competitive interactions. The study concludes that the current practice in the environmental risk assessment of non-target effects of herbicides, where single species are tested in the greenhouse, may be inadequate for assessing the effect of herbicides in semi-natural plant communities. The presented methods can be used for assessing the importance of competitive interactions for the sensitivity of non-target plants to herbicides in risk assessment. PMID:25310805

  13. The Physical and Biochemical Alteration of the Platte River by Phragmites australis, an Invasive Species of Wetland Grass

    NASA Astrophysics Data System (ADS)

    Mohr, R. C.; Krueger, R.; Triplett, L.; Michal, T.; Kettenring, K. M.

    2014-12-01

    Invasive species can have a profound impact on the ecosystems to which they are introduced. Beginning in 2003, the Platte River, Nebraska, USA, was invaded by an aggressive species of wetland grass, Phragmites australis. The invasion by Phragmites, in combination with river flow reductions due to agricultural irrigation, has drastically altered the character and morphology of the river. Once a braided and largely unvegetated river, the Platte had become densely colonized with vegetation by 2010. We measured some physical and biochemical characteristics of Platte River sediments to infer how that vegetation has changed the system. Specifically, we measured particle size, which is an indicator of flow velocity, and biogenic silica (BSi), which is a critical source of silicon for some aquatic organisms. Sediment was collected from areas of the riverbed that are unvegetated, and from areas that are occupied by Phragmites or native vegetation. Particle size was measured using a laser diffractometer to determine how much fine particle deposition was occurring. Biogenic silica (BSi) concentrations were measured using timed NaOH digestions and inductively coupled plasma mass spectrometry (ICP-MS). Our results indicate that stands of Phragmites in the Platte River cause more deposition of finer silt-sized particles than other parts of the river that are unvegetated or are occupied by native vegetation. Also, Phragmites increased the sequestration of BSi in the river sediments. These changes to the Platte reverberate beyond the river itself; by sequestering silica in sediments, Phragmites could be diminishing the supply of silica to estuaries and coastal oceans. Hypothesizing that the silica content of the Platte's water had been reduced by the arrival of Phragmites, we measured dissolved (DSi) and biogenic silica (BSi) concentrations of Platte water using ICP-MS to compare to existing data from the 1990s.

  14. Experimental determination of vertical uprooting resistance for grass species used in flume experiments

    NASA Astrophysics Data System (ADS)

    Edmaier, K.; Crouzy, B.; Ennos, R.; Burlando, P.; Perona, P.

    2012-12-01

    Vegetation affects river morphodynamics by contributing to the stabilization of alluvial sediment via the root system. The survival and establishment of riparian pioneer vegetation on river bars and islands is determined by timescales of vegetation growth and flood interarrival times. Several laboratory experiments have investigated the role of vegetation in river morphodynamics but none of those has quantied the forces involved to produce uprooting of growing plants. Thus, parallel analyses on root resistance to uprooting are needed. In this work we investigate the uprooting resistance of young vegetation in laboratory experiments, where we vertically uprooted seedlings of Avena sativa and Medicago sativa. Uprooting force and work were related to the root structure (root length, number of roots, root tortuosity) and environmental conditions (grain size, saturation). We found the uprooting work of both species to follow a power law relation with the total root length which was found to be the main driving factor of the process. In addition, the number of roots was found to increase uprooting work. For similar total root length, the multi-root system of Avena sativa shows greater uprooting resistance in terms of work than the single-root system of Medicago sativa. Less sediment saturation produces higher uprooting forces and favors root breaking. Smaller sediment sizes lead to a higher uprooting resistance than bigger ones. Nevertheless, both saturation and grain size showed minor influence on the uprooting process compared to root characteristics. From measured uprooting forces of Avena sativa grown on sediment with a grain size distribution similar to that used in the flume experiments of Perona et al. (2012) we computed the ensemble probability of Avena sativa being uprooted by a particular drag force at certain growth stages, allowing us to compute a probability distribution of being uprooted in dependence of the root length and thus experimentally assess the

  15. Competition between a Lawn-Forming Cynodon dactylon and a Tufted Grass Species Hyparrhenia hirta on a South-African Dystrophic Savanna

    PubMed Central

    Zwerts, J. A.; Prins, H. H. T.; Bomhoff, D.; Verhagen, I.; Swart, J. M.; de Boer, W. F.

    2015-01-01

    South African savanna grasslands are often characterised by indigestible tufted grass species whereas lawn grasses are far more desirable in terms of herbivore sustenance. We aimed to investigate the role of nutrients and/or the disturbance (grazing, trampling) by herbivores on the formation of grazing lawns. We conducted a series of common garden experiments to test the effect of nutrients on interspecific competition between a typical lawn-forming grass species (Cynodon dactylon) and a species that is frequently found outside grazing lawns (Hyparrhenia hirta), and tested for the effect of herbivore disturbance in the form of trampling and clipping. We also performed a vegetation and herbivore survey to apply experimentally derived insights to field observations. Our results showed that interspecific competition was not affected by soil nutrient concentrations. C. dactylon did show much more resilience to disturbance than H. hirta, presumably due to the regenerative capacity of its rhizomes. Results from the field survey were in line with these findings, describing a correlation between herbivore pressure and C. dactylon abundance. We conclude that herbivore disturbance, and not soil nutrients, provide C. dactylon with a competitive advantage over H. hirta, due to vegetative regeneration from its rhizomes. This provides evidence for the importance of concentrated, high herbivore densities for the creation and maintenance of grazing lawns. PMID:26510157

  16. Competition between a Lawn-Forming Cynodon dactylon and a Tufted Grass Species Hyparrhenia hirta on a South-African Dystrophic Savanna.

    PubMed

    Zwerts, J A; Prins, H H T; Bomhoff, D; Verhagen, I; Swart, J M; de Boer, W F

    2015-01-01

    South African savanna grasslands are often characterised by indigestible tufted grass species whereas lawn grasses are far more desirable in terms of herbivore sustenance. We aimed to investigate the role of nutrients and/or the disturbance (grazing, trampling) by herbivores on the formation of grazing lawns. We conducted a series of common garden experiments to test the effect of nutrients on interspecific competition between a typical lawn-forming grass species (Cynodon dactylon) and a species that is frequently found outside grazing lawns (Hyparrhenia hirta), and tested for the effect of herbivore disturbance in the form of trampling and clipping. We also performed a vegetation and herbivore survey to apply experimentally derived insights to field observations. Our results showed that interspecific competition was not affected by soil nutrient concentrations. C. dactylon did show much more resilience to disturbance than H. hirta, presumably due to the regenerative capacity of its rhizomes. Results from the field survey were in line with these findings, describing a correlation between herbivore pressure and C. dactylon abundance. We conclude that herbivore disturbance, and not soil nutrients, provide C. dactylon with a competitive advantage over H. hirta, due to vegetative regeneration from its rhizomes. This provides evidence for the importance of concentrated, high herbivore densities for the creation and maintenance of grazing lawns. PMID:26510157

  17. Population structure in the model grass Brachypodium distachyon is highly correlated with flowering differences across broad geographic areas

    DOE PAGESBeta

    Tyler, Ludmila; Lee, Scott J.; Young, Nelson D.; DeIulio, Gregory A.; Benavente, Elena; Reagon, Michael; Sysopha, Jessica; Baldini, Riccardo M.; Troia, Angelo; Hazen, Samuel P.; et al

    2016-04-29

    The small, annual grass Brachypodium distachyon (L.) Beauv., a close relative of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.), is a powerful model system for cereals and bioenergy grasses. Genome-wide association studies (GWAS) of natural variation can elucidate the genetic basis of complex traits but have been so far limited in B. distachyon by the lack of large numbers of well-characterized and sufficiently diverse accessions. Here, we report on genotyping-by-sequencing (GBS) of 84 B. distachyon, seven B. hybridum, and three B. stacei accessions with diverse geographic origins including Albania, Armenia, Georgia, Italy, Spain, and Turkey. Over 90,000 high-qualitymore » single-nucleotide polymorphisms (SNPs) distributed across the Bd21 reference genome were identified. Our results confirm the hybrid nature of the B. hybridum genome, which appears as a mosaic of B. distachyon-like and B. stacei-like sequences. Analysis of more than 50,000 SNPs for the B. distachyon accessions revealed three distinct, genetically defined populations. Surprisingly, these genomic profiles are associated with differences in flowering time rather than with broad geographic origin. High levels of differentiation in loci associated with floral development support the differences in flowering phenology between B. distachyon populations. Genome-wide association studies combining genotypic and phenotypic data also suggest the presence of one or more photoperiodism, circadian clock, and vernalization genes in loci associated with flowering time variation within B. distachyon populations. As a result, our characterization elucidates genes underlying population differences, expands the germplasm resources available for Brachypodium, and illustrates the feasibility and limitations of GWAS in this model grass.« less

  18. Predicting timothy mineral concentrations, dietary cation-anion difference, and grass tetany index by near-infrared reflectance spectroscopy.

    PubMed

    Tremblay, G F; Nie, Z; Bélanger, G; Pelletier, S; Allard, G

    2009-09-01

    The mineral concentration of forage grasses plays a significant role in 2 metabolic disorders in dairy cattle production, namely, hypocalcemia (milk fever) and hypomagnesemia (grass tetany). Risks of occurrence of these 2 metabolic disorders can be evaluated by determining the dietary cation-anion difference (DCAD) and the grass tetany (GT) index of forages and specific rations. The objective of this study was to evaluate the feasibility of predicting timothy (Phleum pratense L.) mineral concentrations of Na, K, Ca, Mg, Cl, S, and P, the DCAD, and the GT index by near-infrared reflectance spectroscopy (NIRS). Timothy samples (n = 1,108) were scanned using NIRS and analyzed for the concentration of 7 mineral elements. Calculations of the DCAD were made using 3 different formulas, and the GT index was also calculated. Samples were divided into calibration (n = 240) and validation (n = 868) sets. The calibration, cross-validation, and prediction for mineral concentrations, the DCAD, and the GT index were performed using modified partial least squares regression. Concentrations of K, Ca, Mg, Cl, and P were successfully predicted with coefficients of determination of prediction (R(P)2) of 0.69 to 0.92 and coefficients of variation of prediction (CV(P)) ranging from 6.6 to 11.4%. The prediction of Na and S concentrations failed, with respective R(P)2 of 0.58 and 0.53 and CV(P) of 82.2 and 12.9%. The 3 calculated DCAD and the GT index were predicted successfully, with R(P)2 >0.90 and CV(P) <20%. Our results confirm the feasibility of using NIRS to predict K, Ca, Mg, and Cl concentrations, as well as the DCAD and the GT index, in timothy. PMID:19700711

  19. Dexamethasone metabolism in vitro: species differences.

    PubMed

    Tomlinson, E S; Maggs, J L; Park, B K; Back, D J

    1997-07-01

    Dexamethasone (DEX) is extensively metabolized to 6-hydroxyDEX (6OH-DEX) and side-chain cleaved metabolites in human liver both in vitro and in vivo with CYP3A4 responsible for the formation of 6-hydroxylated products. In the present study, the metabolism of [3H]DEX has been examined in the liver fractions from various mammalian species and metabolite profiles compared with those obtained with human liver microsomes. Metabolites were quantified by radiometric high-pressure liquid chromatography (HPLC) and characterized by liquid chromatography-mass spectrometry (LC-MS) and co-chromatography with chemical standards, where available. 6OH-DEX formation was quantified for each species and the inhibitory potency of ketoconazole at 1 and 20 microM determined. Glycyrrhetinic acid, a specific inhibitor of 11-dehydrogenase, was also used to determine the extent of reductive DEX metabolism. Species differences in metabolite profiles obtained from microsomal incubations were both quantitative and qualitative. 6-Hydroxylation was variable (highest in the hamster) and was not always the major route of metabolism, and formation was sex-specific in the rat (male > female). The inhibition of 6-hydroxylation (CYP3A) by ketoconazole was variable, and indicates that ketoconazole cannot be regarded as a selective inhibitor of CYP3A proteins in all species. Cytosolic incubations produced similar profiles in different species with the formation of a metabolite (M5) which was inhibited by glycyrrhetinic acid and tentatively identified in this study as 11-dehydro-side-chain cleaved DEX (11DH-9alphaF-A). In conclusion, the male rat gave a metabolite profile which was closest to that seen in the human. However, 6-hydroxylation was most extensive in the hamster which may therefore be a suitable model to use for further studies on DEX metabolism by CYP3A. PMID:9408089

  20. Molecular understandings on 'the never thirsty' and apomictic Cenchrus grass.

    PubMed

    Syamaladevi, Divya P; Meena, S S; Nagar, R P

    2016-03-01

    The genus Cenchrus comprises around 25 species of 'bristle clade' grasses. Cenchrus ciliaris (buffel grass) is a hardy, perennial range grass that survives in poor sandy soils and limiting soil moisture conditions and, due to the very same reasons, this grass is one of the most prevalent fodder grasses of the arid and semi-arid regions. Most of the germplasms of Cenchrus produce seeds asexually through the process of apomeiosis. Therefore, the lack of sufficient sexual lines has hindered the crop improvement efforts in Cenchrus being confined to simple selection methods. Many attempts have been initiated in buffel grass to investigate the various molecular aspects such as genomic signatures of different species and genotypes, molecular basis of abiotic stress tolerance and reproductive performance. Even though it is an important fodder crop, molecular investigations in Cenchrus lack focus and the molecular information available on this grass is scanty. Cenchrus is a very good gene source for abiotic stress tolerance and apomixis studies. Biotechnological interventions in Cenchrus can help in crop improvement in Cenchrus as well as other crops through transgenic technology or marker assisted selection. To date no consolidated review on biotechnological interventions in Cenchrus grass has been published. Therefore we provide a thorough and in depth review on molecular research in Cenchrus focusing on molecular signatures of evolution, tolerance to abiotic stress and apomictic reproductive mechanism. PMID:26601981

  1. Aboveground productivity of C3 and C4 perennial grasses are differentially affected by elevated CO2 and warming in a Wyoming northern mixed-grass prairie

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Responses of North American Great Plains grasslands to global change are uncertain, due in part to differing physiologies of dominant C3 and C4 grasses. Warmer temperatures would presumably favor warm-season, C4 grasses, while rising CO2 would benefit C3 species, whose photosynthetic apparatus is CO...

  2. Greenhouse gas flux under warm-season perennial C4 grasses across different soil and climate gradients on the Islands of Hawaii

    NASA Astrophysics Data System (ADS)

    Pawlowski, M. N.; Crow, S. E.; Sumiyoshi, Y.; Wells, J.; Kikkawa, H. R.

    2011-12-01

    Agricultural soils can serve as either a sink or a source for atmospheric carbon (C) and other greenhouse gases (GHG). This is particularly true for tropical soils where influences from climate and soil gradients are wide ranging. Current estimates of GHG flux from soil are often under or overestimated due to high variability in sample sites and inconsistencies in land use and vegetation type, making extrapolation to new study systems difficult. This work aimed to identify patterns of trace fluxes of carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) across two soil types and three species of warm season perennial C4 grasses: Pennisetum purpureum (Napier grass), Panicum maximum (Guinea grass) and Saccharum officinarum (sugar cane) on the islands of Oahu and Maui in Hawaii. Multiple static vented chambers were installed into replicate plots for each species; flux measurements were made during the growth, fertilization and harvest cycles at set time intervals for one hour and analyzed by gas chromatography. Initial results from Oahu indicate no significant differences in CO2 flux between the P. maximum and P. purpureum species after fertilization or at full growth. We observed an average flux of 143 mg m-2 h-1 and 155 mg m-2 h-1 for P. maximum and P. purpureum respectively at full growth for CO2 and 1.7 μg m-2 h-1and 0.3 μg m-2 h-1 for N2O. Additionally, N2O rates sampled after a typical fertilizer application were significantly greater than at full growth (p=0.0005) with flux rates of 25.2 μg m2h-1 and 30.3 μg m2h-1 for P. maximum and P. purpureum respectively. With a global warming potential of 310 for N2O, even short-term spikes following fertilizer application can cause long lasting effects of GHG emission from agricultural soils. CH4 flux was negligible for all species on the Oahu plots during these sample periods. Globally, water limitation is a major factor influencing the potential productivity of agricultural crops and the sustainability of

  3. Radiocarbon age differences between coexisting foraminiferal species

    NASA Astrophysics Data System (ADS)

    Broecker, Wallace; Matsumoto, Katsumi; Clark, Elizabeth; Hajdas, Irka; Bonani, Georges

    1999-08-01

    Radiocarbon-age measurements on single species of foraminifera from a core on the Ceara Rise demonstrate the importance of the joint effect of bioturbation and variable rain abundance of foraminifera. The relatively high mixed layer ages for Pulleniatina obliquiloculata reflect, at least in part, an early Holocene peak in its abundance while the relatively young ages for Globorotalia menardii reflect the delay until mid Holocene of its reappearance in the Atlantic Ocean. These results clearly demonstrate that core-top sediment samples need not be representative foraminifera falling from today's surface ocean. Rather, at least on the Ceara Rise, such samples consist of a composite of changing species groupings. These results also reconfirm the pitfalls associated with attempts to reconstruct the radiocarbon age of deep ocean water on the basis of benthic-planktonic foraminiferal age differences.

  4. Establishment of non-native plant species after wildfires: Effects of fuel treatments, abiotic and biotic factors, and post-fire grass seeding treatments

    USGS Publications Warehouse

    Hunter, M.E.; Omi, P.N.; Martinson, E.J.; Chong, G.W.

    2006-01-01

    Establishment and spread of non-native species following wildfires can pose threats to long-term native plant recovery. Factors such as disturbance severity, resource availability, and propagule pressure may influence where non-native species establish in burned areas. In addition, pre- and post-fire management activities may influence the likelihood of non-native species establishment. In the present study we examine the establishment of non-native species after wildfires in relation to native species richness, fire severity, dominant native plant cover, resource availability, and pre- and post-fire management actions (fuel treatments and post-fire rehabilitation treatments). We used an information-theoretic approach to compare alternative hypotheses. We analysed post-fire effects at multiple scales at three wildfires in Colorado and New Mexico. For large and small spatial scales at all fires, fire severity was the most consistent predictor of non-native species cover. Non-native species cover was also correlated with high native species richness, low native dominant species cover, and high seeded grass cover. There was a positive, but non-significant, association of non-native species with fuel-treated areas at one wildfire. While there may be some potential for fuels treatments to promote non-native species establishment, wildfire and post-fire seeding treatments seem to have a larger impact on non-native species. ?? IAWF 2006.

  5. Adverse Events During Immunotherapy Against Grass Pollen-Induced Allergic Rhinitis - Differences Between Subcutaneous and Sublingual Treatment.

    PubMed

    Aasbjerg, Kristian; Dalhoff, Kim Peder; Backer, Vibeke

    2015-08-01

    Allergic rhinitis (AR) triggered by grass pollen is a common disease, affecting millions of people worldwide. Treatment consists of symptom-alleviating drugs, such as topical corticosteroids or antihistamines. Another option is potentially curative immunotherapy, currently available as sublingual and subcutaneous treatment. We investigated the potential differences in the prevalence and severity of adverse events related to subcutaneous and sublingual immunotherapy (SLIT) against grass pollen-induced AR. A thorough literature search was performed with PubMed and EMBASE. The findings were compared with the available summaries of product characteristics (SPC) and with commercial pharmacology databases (Micromedex). The majority of available safety data originate from registered products of standardized allergens. A surprisingly large percentage of drugs, especially those used in the United States, have no systematically collected safety data. No sufficiently powered randomized trials comparing sublingual and subcutaneous immunotherapy (SCIT) were available, but general safety assessments indicate that sublingual tablet treatment is safer than subcutaneous treatment. Not all commonly used immunotherapy drugs are officially registered, and not all have systematically collected safety data. This is especially true for older drugs used in the United States. In contrast, newer drugs that have undergone extensive clinical testing have better documentation, but unified collection of safety data is still lacking. Considering the evidence available, most drugs elicit similar side effects from the same organ systems, and symptoms from the sublingual drug classes are probably less severe. However, a head-to-head comparison of safety and efficacy is lacking. PMID:25968654

  6. The effect of ensiling and haymaking on the concentrations of steroidal saponin in two Brachiaria grass species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Brachiaria (signalgrass) is now the most widely used tropical grass genus in Central and South America. However, Brachiaria spp. can cause hepatogenous photosensitization in livestock. Steroidal saponins, specifically protodioscin, present in Brachiaria spp. may be responsible for liver injury and s...

  7. A Comparison of Canopy Evapotranspiration for Maize and Two Perennial Grass Species Identified as Potential Bioenergy Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Perennial rhizomatous grasses (PRGs) that utilize the C4 photosynthetic pathway are considered one of the most promising vegetation types to accommodate a cellulosic feedstock for renewable energy production. The potential widespread use of biomass crops for renewable energy production has sparked n...

  8. Profiles of Nonstructural Carbohydrates, as a Function of Species and Extraction Method, in Four Cool-Season Forage Grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nonstructural carbohydrates (NSC) of forage grasses, particularly long-chain fructans, have been proposed as the causal agent of equine laminitis. In order to evaluate the correlation between NSC and laminitis, NSC must be quantified in the forages being fed to and grazed by horses. The goal of th...

  9. Wounding systemically activates a mitogen-activated protein kinase in forage and turf grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage and turf grasses are continually cut and grazed by livestock, however very little is known concerning the perception or molecular responses to wounding. Mechanical wounding rapidly activated a 46 kDa and a 44 kDa mitogen-activated protein kinase (MAPK) in six different grass species. In the m...

  10. Stripe smuts of grasses: one lineage or high levels of polyphyly?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe smut of grasses, Ustilago striiformis s.l., is caused by a complex of smut fungi widely distributed over temperate and subtropical regions. The disease results in the shredding and death of leaf tissue following the rupture of elongated sori. Nearly 100 different grass species in more than 30...

  11. Establishing native warm season grasses on Eastern Kentucky strip mines

    SciTech Connect

    Barnes, T.G.; Larkin, J.L.; Arnett, M.B.

    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.

  12. Soil sand content can alter effects of different taxa of mycorrhizal fungi on plant biomass production of grassland species

    PubMed Central

    Zaller, Johann G.; Frank, Thomas; Drapela, Thomas

    2011-01-01

    In this greenhouse experiment we tested whether (i) ubiquitous arbuscular mycorrhizal fungi (AMF) taxa (Glomus claroideum, Glomus geosporum, Glomus intraradices, Glomus mosseae) singly and in a mixture differently affect growth and biomass production of four co-occurring grassland species (grass: Arrhenatherum elatius, non-leguminous forbs: Plantago lanceolata, Salvia pratensis and leguminous forb Trifolium pratense), and (ii) different soil sand contents alter AMF influence. We hypothesized that AMF effects on plants will increase with an increased AMF diversity and with increasing sand content. Percent AMF colonization of roots differed between plant species and AMF taxa and was higher with higher sand content. Plant growth responses to AMF were species-specific both regarding plants and AMF. Generally, biomass production of the non-leguminous forbs was the most responsive, the grass species the least and the legume intermediate both for AMF treatments and sand content. Across species, AMF influence on plant biomass increased with increasing soil sand content. Plant species growing in soil containing a mix of four AMF taxa showed similar growth responses than species in soil containing only one AMF taxon. These results suggest that both interference among AMF taxa and soil sand content can trigger the influence of AMF on plant production in grassland species. PMID:26109837

  13. Different Leishmania Species Drive Distinct Neutrophil Functions.

    PubMed

    Hurrell, Benjamin P; Regli, Ivo B; Tacchini-Cottier, Fabienne

    2016-05-01

    Leishmaniases are vector-borne diseases of serious public health importance. During a sand fly blood meal, Leishmania parasites are deposited in the host dermis where neutrophils are rapidly recruited. Neutrophils are the first line of defense and can kill pathogens by an array of mechanisms. They can also form web-like structures called neutrophil extracellular traps (NETs) that can trap and/or kill microbes. The function of neutrophils in leishmaniasis was reported to be either beneficial by contributing to parasite killing or detrimental by impairing immune response development and control of parasite load. Here we review recent data showing that different Leishmania species elicit distinct neutrophil functions thereby influencing disease outcomes. Emerging evidence suggests that neutrophils should be considered important modulators of leishmaniasis. PMID:26944469

  14. Phylogenetic niche conservatism in C4 grasses.

    PubMed

    Liu, Hui; Edwards, Erika J; Freckleton, Robert P; Osborne, Colin P

    2012-11-01

    Photosynthetic pathway is used widely to discriminate plant functional types in studies of global change. However, independent evolutionary lineages of C(4) grasses with different variants of C(4) photosynthesis show different biogeographical relationships with mean annual precipitation, suggesting phylogenetic niche conservatism (PNC). To investigate how phylogeny and photosynthetic type differentiate C(4) grasses, we compiled a dataset of morphological and habitat information of 185 genera belonging to two monophyletic subfamilies, Chloridoideae and Panicoideae, which together account for 90 % of the world's C(4) grass species. We evaluated evolutionary variance and covariance of morphological and habitat traits. Strong phylogenetic signals were found in both morphological and habitat traits, arising mainly from the divergence of the two subfamilies. Genera in Chloridoideae had significantly smaller culm heights, leaf widths, 1,000-seed weights and stomata; they also appeared more in dry, open or saline habitats than those of Panicoideae. Controlling for phylogenetic structure showed significant covariation among morphological traits, supporting the hypothesis of phylogenetically independent scaling effects. However, associations between morphological and habitat traits showed limited phylogenetic covariance. Subfamily was a better explanation than photosynthetic type for the variance in most morphological traits. Morphology, habitat water availability, shading, and productivity are therefore all involved in the PNC of C(4) grass lineages. This study emphasized the importance of phylogenetic history in the ecology and biogeography of C(4) grasses, suggesting that divergent lineages need to be considered to fully understand the impacts of global change on plant distributions. PMID:22569558

  15. Diffusion limitations and metabolic factors associated with inhibition and recovery of photosynthesis from drought stress in a C perennial grass species.

    PubMed

    Hu, Longxing; Wang, Zhaolong; Huang, Bingru

    2010-05-01

    Stomatal closure and metabolic impairment under drought stress limits photosynthesis. The objective of this study was to determine major stomatal and metabolic factors involved in photosynthetic responses to drought and recovery upon re-watering in a C(3) perennial grass species, Kentucky bluegrass (Poa pratensis L.). Two genotypes differing in drought resistance, 'Midnight' (tolerant) and 'Brilliant' (sensitive), were subjected to drought stress for 15 days and then re-watered for 10 days in growth chambers. Single-leaf net photosynthetic rate (A), stomatal conductance (g(s)) and transpiration rate (Tr) decreased during drought, with a less rapid decline in 'Midnight' than in 'Brilliant'. Photochemical efficiency, Rubisco activity and activation state declined during drought, but were significantly higher in 'Midnight' than in 'Brilliant'. The relationship between A and internal leaf CO(2) concentration (A/Ci curve) during drought and re-watering was analyzed to estimate the relative influence of stomatal and non-stomatal components on photosynthesis. Stomatal limitation (Ls %), non-stomatal limitation (Lns %), CO(2) compensation point (CP) and dark respiration (Rd) increased with stress duration in both genotypes, but to a lesser extent in 'Midnight'. Maximum CO(2) assimilation rate (A(max)), carboxylation efficiency (CE) and mesophyll conductance (g(m)) declined, but 'Midnight' had significantly higher levels of A(max), CE and g(m) than 'Brilliant'. Maximum carboxylation rate of Rubisco (V(cmax)) and ribulose-1,5-bisphospate (RuBP) regeneration capacity mediated by maximum electron transport rate (J(max)) decreased from moderate to severe drought stress in both genotypes, but to a greater extent in 'Brilliant' than in 'Midnight'. After re-watering, RWC restored to about 90% of the control levels in both genotypes, whereas A, g(s), Tr and Fv/Fm was only partially recovered, with a higher recovery level in 'Midnight' than in 'Brilliant'. Rubisco activity and

  16. LIGNIN ACYLATION IN GRASSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acylation of lignin during growth and development is a commonly found among some plant species. Grasses form unique acylated lignins involving p-coumarate (pCA). In corn rind tissue, it is exclusively attached to the gamma-carbon of lignin monomers, with a strong preference (over 90%) for attachment...

  17. Metabolite production by different Ulocladium species.

    PubMed

    Andersen, Birgitte; Hollensted, Morten

    2008-08-15

    Ulocladium, which is phylogenetically related to Alternaria, contains species that are food spoilers and plant pathogens, but also species that have potential as enzyme producers and bio-control agents. Ulocladium spp. are often found on dead vegetation, in soil, air and dust, but also on food and feedstuffs and on water-damaged building materials. The aim was to study the morphological and chemical diversity within the genus Ulocladium. Cultures of 52 Ulocladium strains were identified morphologically, and then extracted and analyzed using automated Chemical Image Analysis. Production of individual metabolites was correlated to species identity and source of isolation (substratum). Chemical analyses corroborated the morphological identifications and showed the existence of several species species-specific metabolites, of which most were known compounds. The production of curvularins was specific to Ulocladium atrum, while most species produced infectopyrones and derivatives of altertoxin I. None of the 52 Ulocladium strains produced alternariols, tenuazonic acid, altersolanols or macrosporin, which are common in species of Alternaria. PMID:18599140

  18. A high loading overland flow system: Impacts on soil characteristics, grass constituents, yields and nutrient removal.

    PubMed

    Wen, C G; Chen, T H; Hsu, F H; Lu, C H; Lin, J B; Chang, C H; Chang, S P; Lee, C S

    2007-04-01

    The objectives of this paper are to determine effects of different grass species and their harvests on pollutant removal, elucidate impacts on soil characteristics and grass constituents, observe grass yield and quantify nutrient uptake by vegetation in an overland flow system (OLFS). Polluted creek water was applied to eight channels in the OLFS, which were planted with Paragrass, Nilegrass, Cattail, and Vetiver, with each two channels being randomly planted with a given grass species. The grass in one channel was harvested while that in the other channel was not. At a high rate of 27.8 m d(-1) hydraulic loading, the removal efficiencies of conventional pollutants such as BOD, COD, suspended solids (SS), and total coliforms in wastewater are not affected by the type of the grasses species, but those of nitrogen and phosphorus are affected by different species. Overall average removal efficiencies of BOD, COD, SS, ammonia, total nitrogen, total phosphorus and total coliforms through the OLFS are 42%, 48%, 78%, 47%, 40%, 33% and 89%, respectively. The concentration of nitrate, however, increases due to nitrification. Soil characteristics in OLFS have been changed significantly; specific conductivity, organic matter, exchangeable magnesium, extractable copper and zinc in soils all increase with time while pHs decrease. During the winter season, there is a significant accumulation of nitrate in grass with the subsequent reduction during the active growing season (Spring). The contents of nitrate and phosphorus in grass tissue are higher than those of grass in general pastureland, probably due to nutrient luxury uptake by grass. The overall grass yield, growth rate and nutrient uptake are quantified and implication of such high rate OLFS discussed. PMID:17234253

  19. Architectural Evolution and its Implications for Domestication in Grasses

    PubMed Central

    Doust, Andrew

    2007-01-01

    Background The cereal crops domesticated from grasses provide a large percentage of the calories consumed by humans. Domestication and breeding in individual cereals has historically occurred in isolation, although this is rapidly changing with comparative genomics of the sequenced or soon-to-be sequenced genomes of rice, sorghum, maize and Brachypodium. Genetic information transferred through genomic comparisons is helping our understanding of genetically less tractable crops such as the hexaploid wheats and polyploid sugarcane, as well as the approx. 10 000 species of wild grasses. In turn, phylogenetic analysis helps put our knowledge of the morphology of cereal crops into an evolutionary context. Grass Architecture Domestication often involves a change in the pattern and timing of branching, which affects both vegetative and inflorescence architecture, and ultimately yield. Cereal grasses exhibit two main forms of vegetative architecture: the pooid and erhartoid cereals such as wheat and rice have multiple basal tillers, while panicoid cereals such as maize, sorghum and the millets have few tillers or even only a single main stem. These differences are reflected in the differences between the wild species of pooid and some erhartoid grasses, which emphasize basal branching over axillary branching, and the panicoid grasses, where axillary branching is more frequently found. A combination of phylogenetic and genomic analysis is beginning to reveal the similarities and differences between different cereal crops, and relate these to the diversity of wild grasses to which they are related. Recent work on genes controlling branching emphasizes that developmental genetics needs to be viewed in both an evolutionary and ecological framework, if it is to be useful in understanding how morphology evolves. Increasingly, exploring the phylogenetic context of the crop grasses will suggest new ways to identify and create combinations of morphological traits that will best

  20. Species interactions differ in their genetic robustness

    DOE PAGESBeta

    Chubiz, Lon M.; Granger, Brian R.; Segre, Daniel; Harcombe, William R.

    2015-04-14

    Conflict and cooperation between bacterial species drive the composition and function of microbial communities. Stability of these emergent properties will be influenced by the degree to which species' interactions are robust to genetic perturbations. We use genome-scale metabolic modeling to computationally analyze the impact of genetic changes when Escherichia coli and Salmonella enterica compete, or cooperate. We systematically knocked out in silico each reaction in the metabolic network of E. coli to construct all 2583 mutant stoichiometric models. Then, using a recently developed multi-scale computational framework, we simulated the growth of each mutant E. coli in the presence of S.more » enterica. The type of interaction between species was set by modulating the initial metabolites present in the environment. We found that the community was most robust to genetic perturbations when the organisms were cooperating. Species ratios were more stable in the cooperative community, and community biomass had equal variance in the two contexts. Additionally, the number of mutations that have a substantial effect is lower when the species cooperate than when they are competing. In contrast, when mutations were added to the S. enterica network the system was more robust when the bacteria were competing. These results highlight the utility of connecting metabolic mechanisms and studies of ecological stability. Cooperation and conflict alter the connection between genetic changes and properties that emerge at higher levels of biological organization.« less

  1. Urban Rights-of-Way as Reservoirs for Tall-Grass Prairie Plants and Butterflies.

    PubMed

    Leston, Lionel; Koper, Nicola

    2016-03-01

    Urban rights-of-way may be potential reservoirs of tall-grass prairie plants and butterflies. To determine if this is true, in 2007-2008, we conducted vegetation surveys of species richness and cover, and butterfly surveys of species richness and abundance, along 52 transmission lines and four remnant prairies in Winnipeg, Manitoba. We detected many prairie plants and butterflies within transmission lines. Some unmowed and infrequently managed transmission lines had native plant species richness and total percent cover of native plants comparable to that of similar-sized remnant tall-grass prairies in the region. Although we did not find significant differences in overall native butterfly numbers or species richness between rights-of-way and remnant prairies, we found lower numbers of some prairie butterflies along frequently mowed rights-of-way than within remnant tall-grass prairies. We also observed higher butterfly species richness along sites with more native plant species. By reducing mowing and spraying and reintroducing tall-grass prairie plants, urban rights-of-way could serve as extensive reservoirs for tall-grass prairie plants and butterflies in urban landscapes. Eventually, managing urban rights-of-way as reservoirs for tall-grass prairie plants and animals could contribute to the restoration of tall-grass prairie in the North American Midwest. PMID:26604009

  2. Urban Rights-of-Way as Reservoirs for Tall-Grass Prairie Plants and Butterflies

    NASA Astrophysics Data System (ADS)

    Leston, Lionel; Koper, Nicola

    2016-03-01

    Urban rights-of-way may be potential reservoirs of tall-grass prairie plants and butterflies. To determine if this is true, in 2007-2008, we conducted vegetation surveys of species richness and cover, and butterfly surveys of species richness and abundance, along 52 transmission lines and four remnant prairies in Winnipeg, Manitoba. We detected many prairie plants and butterflies within transmission lines. Some unmowed and infrequently managed transmission lines had native plant species richness and total percent cover of native plants comparable to that of similar-sized remnant tall-grass prairies in the region. Although we did not find significant differences in overall native butterfly numbers or species richness between rights-of-way and remnant prairies, we found lower numbers of some prairie butterflies along frequently mowed rights-of-way than within remnant tall-grass prairies. We also observed higher butterfly species richness along sites with more native plant species. By reducing mowing and spraying and reintroducing tall-grass prairie plants, urban rights-of-way could serve as extensive reservoirs for tall-grass prairie plants and butterflies in urban landscapes. Eventually, managing urban rights-of-way as reservoirs for tall-grass prairie plants and animals could contribute to the restoration of tall-grass prairie in the North American Midwest.

  3. Feeding behavior, ruminal fermentation, and performance of pregnant beef cows differing in phenotypic residual feed intake offered grass silage.

    PubMed

    Fitzsimons, C; Kenny, D A; Fahey, A G; McGee, M

    2014-05-01

    -RFI cows had more and a longer total duration of nonfeeding events (P < 0.001) than low-RFI cows. This study showed that compared to cows with high RFI, those with low RFI consumed less feed for similar levels of productivity, spent less time engaged in feeding-behavior-related activities, and differed in ruminal fermentation parameters. Feeding events are a significant (17%) contributory factor to variation in RFI in pregnant beef cows offered grass silage. PMID:24663212

  4. Variation of soil and plant characteristics among old world bluestem species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Old world bluestems (Bothriochloa spp.) have been successfully introduced as grasses for livestock forage in the semiarid Texas High Plains. Questions remain, however, on effects of these grasses on soil resources. We tested the hypothesis that differences in grass species produce differences in so...

  5. Species interactions differ in their genetic robustness

    SciTech Connect

    Chubiz, Lon M.; Granger, Brian R.; Segre, Daniel; Harcombe, William R.

    2015-04-14

    Conflict and cooperation between bacterial species drive the composition and function of microbial communities. Stability of these emergent properties will be influenced by the degree to which species' interactions are robust to genetic perturbations. We use genome-scale metabolic modeling to computationally analyze the impact of genetic changes when Escherichia coli and Salmonella enterica compete, or cooperate. We systematically knocked out in silico each reaction in the metabolic network of E. coli to construct all 2583 mutant stoichiometric models. Then, using a recently developed multi-scale computational framework, we simulated the growth of each mutant E. coli in the presence of S. enterica. The type of interaction between species was set by modulating the initial metabolites present in the environment. We found that the community was most robust to genetic perturbations when the organisms were cooperating. Species ratios were more stable in the cooperative community, and community biomass had equal variance in the two contexts. Additionally, the number of mutations that have a substantial effect is lower when the species cooperate than when they are competing. In contrast, when mutations were added to the S. enterica network the system was more robust when the bacteria were competing. These results highlight the utility of connecting metabolic mechanisms and studies of ecological stability. Cooperation and conflict alter the connection between genetic changes and properties that emerge at higher levels of biological organization.

  6. Underutilized Grasses.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Perennial warm-season grasses have been recognized for having several properties, such as high rates of net photosynthesis, energy and labor savings, and reduced soil and nutrient losses that make them better suited for biofuel production than many annual crops. Prairie cordgrass (Spartina pectinat...

  7. Ornamental Landscape Grasses. Slide Script.

    ERIC Educational Resources Information Center

    Still, Steven M.; Adams, Denise W.

    This slide script to accompany the slide series, Ornamental Landscape Grasses, contains photographs of the 167 slides and accompanying narrative text intended for use in the study and identification of commercially important ornamental grasses and grasslike plants. Narrative text is provided for slides of 62 different perennial and annual species…

  8. Phytotoxic Activity of Ocimum tenuiflorum Extracts on Germination and Seedling Growth of Different Plant Species

    PubMed Central

    2014-01-01

    Phytotoxic activity of Ocimum tenuiflorum (Lamiaceae) plant extracts was investigated against the germination and seedling growth of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), Italian ryegrass (Lolium multiflorum), barnyard grass (Echinochloa crus-galli), and timothy (Phleum pratense) at four different concentrations. The plant extracts at concentrations greater than 30 mg dry weight equivalent extract mL−1 reduced significantly the total germination percent (GP), germination index (GI), germination energy (GE), speed of emergence (SE), seedling vigour index (SVI), and coefficient of the rate of germination (CRG) of all test species except barnyard grass and GP of lettuce. In contrast, time required for 50% germination (T50) and mean germination time (MGT) were increased at the same or higher than this concentration. The increasing trend of T50 and MGT and the decreasing trend of other indices indicated a significant inhibition or delay of germination of the test species by O. tenuiflorum plant extracts and vice versa. In addition, the shoot and root growth of all test species were significantly inhibited by the extracts at concentrations greater than 10 mg dry weight equivalent extract mL−1. The I50 values for shoot and root growth were ranged from 26 to 104 mg dry weight equivalent extract mL−1. Seedling growth was more sensitive to the extracts compared to seed germination. Results of this study suggest that O. tenuiflorum plant extracts have phytotoxic properties and thus contain phytotoxic substances. Isolation and characterization of those substances from this plant may act as a tool for new natural, biodegradable herbicide development to control weeds. PMID:25032234

  9. Evolutionary relationship of nuclear genes encoding mitochondrial proteins across grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Comparative genome studies were done across taxa to provide a basic understanding of genome evolution regarding nuclear genes encoding for mitochondrial proteins and their conservation in grass species. Two different mitochondria-related gene sets, one from rice and another from Arabidopsis, were us...

  10. Examining differences between recovered and declining endangered species

    USGS Publications Warehouse

    Abbitt, R.J.F.; Michael, Scott J.

    2001-01-01

    Between 1973 and 1999, 43 species in the United States were reclassified from endangered to threatened or removed entirely from the Endangered Species List. Of these, 23 were identified as recovered. In 1999 the U.S. Fish and Wildlife Service (USFWS) published a list of 33 additional species for possible reclassification and/or delisting. We initiated this study to examine why some endangered species recover but others continue to decline and to identify differences in management activities between these two groups. We defined recovered/recovering species as previously recovered species and the additional recovered/recovering species listed by the USFWS. We defined declining species as those identified as declining in the most recent USFWS Report to Congress. Information on recovered/recovering and declining species was gathered from relevant literature, recovery plans, U.S. Federal Register documents, and individuals responsible for the recovery management of each species. We used this information to examine (1) the percentage of current and historic range covered by management activities; (2) threats affecting the species; (3) population sizes at the time of listing; (4) current versus historic range size; and (5) percentage of recovery management objectives completed. Although few statistical analyses provided significant results, those that did suggest the following differences between recovered/recovering and declining species: (1) recovered/recovering species face threats that are easier to address; (2) recovered/recovering species occupy a greater percentage of their historic range; and (3) recovered/recovering species have a greater percentage of their recovery management objectives completed. Those species with threats easier to address and that occupy a greater percentage of their historic range are recovered/recovering. In contrast, declining species face threats more difficult to address and occupy significantly less of their historic range. If this

  11. Salinity tolerance of foxtail barley (Hordeum jubatum) and desirable pasture grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouse studies were conducted to determine the relative salinity tolerance of foxtail barley and seven desirable pasture grasses. Grass species were reed canarygrass, timothy, altai wildrye, tall fescue, tall wheatgrass, orchardgrass, creeping meadow foxtail, and foxtail barley. Grasses were e...

  12. Effect of different levels of raw and heated grass pea seed (Lathyrus sativus) on nutrient digestibility, intestinal villus morphology and growth performance of broiler chicks.

    PubMed

    Riasi, A; Mahdavi, A H; Bayat, E

    2015-10-01

    This study aimed to investigate chemical composition and effect of different levels (0%, 10% and 20%) of raw grass pea (RGP) and heat-treated (120 °C for 30 min) grass pea seed (HGP) on nutrient digestibility, dressing percentage, relative internal organ weights, intestinal villous morphology and broiler chicks' performance. A total number of 200 day-old male chicks were raised under similar condition for 10 days. On day 11, chicks were randomly assigned to five dietary treatments and four replicates of 10 birds each. The result of chemical analysis indicated that Iranian grass pea seed has low levels of total and condensed tannin, and it may be considered as a good source of protein (36.1%) and energy (17.09 kJ GE/g). Heat treatment reduced (p < 0.05) the total and condensed tannin to 21% and 78% respectively. Grass peas seed had higher levels of nitrogen-free extract, P, Na, Mg and Zn than soya bean meal. The apparent digestibility of gross energy and lipid was affected (p < 0.01) by the treatment diets, and it was the lowest after feeding 20% of HGP (p < 0.05). The relative weight of breast and pancreas (p < 0.05) was affected by treatments. Percentage weight of breast and pancreas increased (p < 0.05) after feeding high levels (20%) of RGP and HGP. Substitution of 20% of RGP and HGP increased the duodenal crypt depth (p < 0.05); however, it had no suppressive effect on villus height as the absorptive surface of intestine. The feed conversion ratio was not affected by the treatments in the total experimental period. This study showed that, although the high level of grass pea seed caused a remarkable increase in the relative weight of pancreas and decreased the apparent digestibility of gross energy and lipid, it had beneficial effect on breast relative weight. It seems that heat processing is not effective method for improving quality of Iranian grass pea seed. PMID:25846572

  13. [Optimized Spectral Indices Based Estimation of Forage Grass Biomass].

    PubMed

    An, Hai-bo; Li, Fei; Zhao, Meng-li; Liu, Ya-jun

    2015-11-01

    As an important indicator of forage production, aboveground biomass will directly illustrate the growth of forage grass. Therefore, Real-time monitoring biomass of forage grass play a crucial role in performing suitable grazing and management in artificial and natural grassland. However, traditional sampling and measuring are time-consuming and labor-intensive. Recently, development of hyperspectral remote sensing provides the feasibility in timely and nondestructive deriving biomass of forage grass. In the present study, the main objectives were to explore the robustness of published and optimized spectral indices in estimating biomass of forage grass in natural and artificial pasture. The natural pasture with four grazing density (control, light grazing, moderate grazing and high grazing) was designed in desert steppe, and different forage cultivars with different N rate were conducted in artificial forage fields in Inner Mongolia. The canopy reflectance and biomass in each plot were measured during critical stages. The result showed that, due to the influence in canopy structure and biomass, the canopy reflectance have a great difference in different type of forage grass. The best performing spectral index varied in different species of forage grass with different treatments (R² = 0.00-0.69). The predictive ability of spectral indices decreased under low biomass of desert steppe, while red band based spectral indices lost sensitivity under moderate-high biomass of forage maize. When band combinations of simple ratio and normalized difference spectral indices were optimized in combined datasets of natural and artificial grassland, optimized spectral indices significant increased predictive ability and the model between biomass and optimized spectral indices had the highest R² (R² = 0.72) compared to published spectral indices. Sensitive analysis further confirmed that the optimized index had the lowest noise equivalent and were the best performing index in

  14. The effect of exotic grass Urochloa decumbens (Stapf) R.D.Webster (Poaceae) in the reduction of species richness and change of floristic composition of natural regeneration in the Floresta Nacional de Carajás, Brazil.

    PubMed

    Ferreira, Leandro V; Parolin, Pia; Matos, Darley C L; Cunha, Denise A; Chaves, Priscilla P; Neckel, Selvino O

    2016-01-01

    The introduction of exotic species is considered as one of the major causes of biodiversity loss. The National Forest of Carajás is one of the largest mineral provinces in the world. Mining activities caused changes of the natural habitats, leaving degraded areas after the mineral exploitation. One of the mining areas within FLONA Carajás was used for the extraction of gold. In the process of exploitation, a huge depression was formed by the removal of soil which was mounded up nearby. To prevent soil erosion of these mounds, an exotic grass, Urochloa decumbens (Stapf) R.D.Webster (Poaceae) was planted. The objective of this study was to compare the impact of this non-native grass on species richness and species composition of the natural regeneration in the degraded areas. Four areas were compared, two with and two without presence of U. decumbens. In each area, twenty four 1m²/plots were established. Species richness of the regeneration areas and population sizes were significantly lower in the plots where the exotic grass was present. Our study shows that U. decumbens had a negative effect on species richness and population density, and its presence changed the species composition and distribution of life forms of the natural regeneration. PMID:27142539

  15. Characterizing compositional changes of Napier grass at different stages of growth for biofuel and biobased products potential.

    PubMed

    Takara, Devin; Khanal, Samir Kumar

    2015-01-01

    Napier grass, Pennisetum purpureum, is a high yielding, perennial feedstock that can be harvested year-round in (sub)tropical geographies of the world. Because of its high moisture content (∼ 80%w/w), Napier grass presents a unique opportunity for fractionation into solid and liquid streams, where the extruded cellulosic fibers can serve as a substrate for biofuel production, and the nutrient-rich juice can serve as a substrate for co-product generation. The aim of this study evaluated the effects of biomass age on constituents relevant to biofuel and biobased product generation. Although obvious morphological changes can be observed in the field due to natural senescence, the results obtained in this work suggested that the cellulose content does not change significantly with respect to age. Data surrounding the hemicellulose and lignin contents, however, were inconclusive as their degree of significance varied with the statistics applied to analyze the raw data. PMID:25727997

  16. Nucelotide Diversity and Molecular Evolution of the PSY1 Gene in Zea mays Compared to some Other Grass Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytoene synthase is the first rate-limiting enzyme in the plant carotenoid biosynthetic pathway, and is encoded by the phytoene synthase 1 (PSY1) gene. To examine the genetic diversity and pattern of evolution of PSY1 within the Andropogoneae, sequences of 76 accessions from 5 species (including ma...

  17. Lr34 multi-pathogen resistance ABC transporter: molecular analysis of homoeologous and orthologous genes in hexaploid wheat and other grass species.

    PubMed

    Krattinger, Simon G; Lagudah, Evans S; Wicker, Thomas; Risk, Joanna M; Ashton, Anthony R; Selter, Liselotte L; Matsumoto, Takashi; Keller, Beat

    2011-02-01

    The Triticum aestivum (bread wheat) disease resistance gene Lr34 confers durable, race non-specific protection against three fungal pathogens, and has been a highly relevant gene for wheat breeding since the green revolution. Lr34, located on chromosome 7D, encodes an ATP-binding cassette (ABC) transporter. Both wheat cultivars with and without Lr34-based resistance encode a putatively functional protein that differ by only two amino acid polymorphisms. In this study, we focused on the identification and characterization of homoeologous and orthologous Lr34 genes in hexaploid wheat and other grasses. In hexaploid wheat we found an expressed and putatively functional Lr34 homoeolog located on chromosome 4A, designated Lr34-B. Another homoeologous Lr34 copy, located on chromosome 7A, was disrupted by the insertion of repetitive elements. Protein sequences of LR34-B and LR34 were 97% identical. Orthologous Lr34 genes were detected in the genomes of Oryza sativa (rice) and Sorghum bicolor (sorghum). Zea mays (maize), Brachypodium distachyon and Hordeum vulgare (barley) lacked Lr34 orthologs, indicating independent deletion of this particular ABC transporter. Lr34 was part of a gene-rich island on the wheat D genome. We found gene colinearity on the homoeologous A and B genomes of hexaploid wheat, but little microcolinearity in other grasses. The homoeologous LR34-B protein and the orthologs from rice and sorghum have the susceptible haplotype for the two critical polymorphisms distinguishing the LR34 proteins from susceptible and resistant wheat cultivars. We conclude that the particular Lr34-haplotype found in resistant wheat cultivars is unique. It probably resulted from functional gene diversification that occurred after the polyploidization event that was at the origin of cultivated bread wheat. PMID:21265893

  18. An overview of X inactivation based on species differences.

    PubMed

    Migeon, Barbara R

    2016-08-01

    X inactivation, a developmental process that takes place in early stages of mammalian embryogenesis, balances the sex difference in dosage of X-linked genes. Although all mammals use this form of dosage compensation, the details differ from one species to another because of variations in the staging of embryogenesis and evolutionary tinkering with the DNA blueprint for development. Such differences provide a broader view of the process than that afforded by a single species. My overview of X inactivation is based on these species variations. PMID:26805440

  19. Distinct Effects of Different Phosphatidylglycerol Species on Mouse Keratinocyte Proliferation

    PubMed Central

    Xie, Ding; Seremwe, Mutsa; Edwards, John G.; Podolsky, Robert; Bollag, Wendy B.

    2014-01-01

    We have previously shown that liposomes composed of egg-derived phosphatidylglycerol (PG), with a mixed fatty acid composition (comprising mainly palmitate and oleate), inhibit the proliferation and promote the differentiation of rapidly dividing keratinocytes, and stimulate the growth of slowly proliferating epidermal cells. To determine the species of PG most effective at modulating keratinocyte proliferation, primary mouse keratinocytes were treated with different PG species, and proliferation was measured. PG species containing polyunsaturated fatty acids were effective at inhibiting rapidly proliferating keratinocytes, whereas PG species with monounsaturated fatty acids were effective at promoting proliferation in slowly dividing cells. Thus, palmitoyl-arachidonyl-PG (16∶0/20∶4), palmitoyl-linoleoyl-PG (16∶0/18∶2), dilinoleoyl-PG (18∶2/18∶2) and soy PG (a PG mixture with a large percentage of polyunsaturated fatty acids) were particularly effective at inhibiting proliferation in rapidly dividing keratinocytes. Conversely, palmitoyl-oleoyl-PG (16∶0/18∶1) and dioleoyl-PG (18∶1/18∶1) were especially effective proproliferative PG species. This result represents the first demonstration of opposite effects of different species of a single class of phospholipid and suggests that these different PG species may signal to diverse effector enzymes to differentially affect keratinocyte proliferation and normalize keratinocyte proliferation. Thus, different PG species may be useful for treating skin diseases characterized by excessive or insufficient proliferation. PMID:25233484

  20. Mycorrhizal fungi affect root stele tissue in grasses.

    SciTech Connect

    Miller, R. M.; Hetrick, B. A. D.; Wilson, G. W. T.; Environmental Research; Northern Iowa Univ.; Kansas State Univ.

    1997-01-01

    Although arbuscular mycorrhizal symbiosis was initially believed to have little or no impact on root morphology, we now recognize that subtle changes do occur and that these changes may be of considerable consequence to host growth and nutrition, as well as functional growth strategy. In examining the stele and root diameters of C3 and C4 grasses, C4 grasses were demonstrated to have a significantly larger proportion of their fibrous roots occupied by stele tissue than do C3 grasses. In fact, functional growth strategy (C3 versus C4) was observed to be a relatively good predictor of stele area. Mycorrhizal fungi also influenced the amount of stele tissue, but the effect was not the same for both C3 and C4 grasses. The stele area of all C4 grasses except for Sorghastrum nutans was greater in the presence of mycorrhizal colonization. Among the C3 grasses, only Bromus inermis showed a significant increase, although Elymus cinereus and Lolium perenne displayed significant decreases in response to arbuscular mycorrhizal colonization. Changes in the stele area of the plant species were closely related to their responsiveness to mycorrhizal symbiosis and might in part explain both beneficial and detrimental responses of plants to mycorrhizae. An increase in stele circumference induced by mycorrhizae would allow for greater uptake and passage of water and nutrients to the vascular cylinder, and growth depressions could be a direct outcome of reduced stele circumference. Thus, differences in stele circumference represent a possible mechanism for mycorrhizal impacts on host plants. These findings indicate that structural differences among grasses are related to different functional capabilities and further emphasize the need for better integration of comparative anatomy and morphology procedures in the study of mycorrhizal symbiosis.

  1. The effect of nitrogen and glyphosate on survival and colonisation of perennial grass species in an agro-ecosystem: does the relative importance of survival decrease with competitive ability?

    PubMed

    Damgaard, Christian; Strandberg, Beate; Mathiassen, Solvejg K; Kudsk, Per

    2013-01-01

    The ecological success of a plant species is typically described by the observed change in plant abundance or cover, but in order to more fully understand the fundamental plant ecological processes, it is necessary to inspect the underlying processes of survival and colonization and how they are affected by environmental conditions. A general ecological hypothesis on the effect of environmental gradients on demographic parameters is proposed and tested. The hypothesis is that decreasing fitness or competitive ability along an environmental gradient is associated with an increasing importance of survival for regulating the abundance of the species. The tested hypothesis is related to both the stress gradient hypothesis and whether the importance of competition increases along productivity gradients. The combined effect of nitrogen and glyphosate on the survival and colonization probability of two perennial grass species, Festuca ovina and Agrostis capillaris, which are known to differ in their responses to both glyphosate and nitrogen treatments, is calculated using pin-point cover data in permanent frames. We found that the relative importance of survival increased with the level of glyphosate for the glyphosate sensitive A. capillaris and decreased for the glyphosate tolerant F. ovina. Likewise, increasing levels of nitrogen increased the importance of survival for the relative nitrophobic F. ovina. Consequently, the proposed hypothesis was corroborated in this specific study. The proposed method will enable predictions of the effects of agricultural practices on community dynamics in a relatively simple setup eliminating the need to quantify all the interaction among the species in the plant community. The method will be immediately useful for the regulation of non-cultivated buffer strips between agricultural fields and semi-natural and natural biotopes such as hedgerows and waterways. PMID:23593371

  2. Detection of Different DNA Animal Species in Commercial Candy Products.

    PubMed

    Muñoz-Colmenero, Marta; Martínez, Jose Luis; Roca, Agustín; Garcia-Vazquez, Eva

    2016-03-01

    Candy products are consumed all across the world, but there is not much information about their composition. In this study we have used a DNA-based approach for determining the animal species occurring in 40 commercial candies of different types. We extracted DNA and performed PCR amplification, cloning and sequencing for obtaining species-informative DNA sequences. Eight species were identified including fish (hake and anchovy) in 22% of the products analyzed. Bovine and porcine were the most abundant appearing in 27 samples each one. Most products contained a mixture of species. Marshmallows (7), jelly-types, and gummies (20) contained a significantly higher number of species than hard candies (9). We demonstrated the presence of DNA animal species in candy product which allow consumers to make choices and prevent allergic reaction. PMID:26807698

  3. Heat Shock Proteins in Association with Heat Tolerance in Grasses

    PubMed Central

    Xu, Yan; Zhan, Chenyang; Huang, Bingru

    2011-01-01

    The grass family Poaceae includes annual species cultivated as major grain crops and perennial species cultivated as forage or turf grasses. Heat stress is a primary factor limiting growth and productivity of cool-season grass species and is becoming a more significant problem in the context of global warming. Plants have developed various mechanisms in heat-stress adaptation, including changes in protein metabolism such as the induction of heat shock proteins (HSPs). This paper summarizes the structure and function of major HSPs, recent research progress on the association of HSPs with grass tolerance to heat stress, and incorporation of HSPs in heat-tolerant grass breeding. PMID:22084689

  4. Arsenic and mercury in native aquatic bryophytes: differences among species.

    PubMed

    Díaz, Santiago; Villares, Rubén; López, Jesús; Carballeira, Alejo

    2013-04-01

    This study investigated the capacities of five species of aquatic bryophytes to accumulate As and Hg from their natural habitats in rivers in Galicia (NW Spain). The distributions of the concentrations of both elements in all species were skewed to the right, with a higher incidence of extreme values in the As data, which may indicate a greater degree of contamination by this metalloid. There were no significant differences in the accumulation of either of the elements between the different species studied, which justifies their combined use as biomonitors of As and Hg, at least in the study area. PMID:23275977

  5. Differences in hoarding behaviors among six sympatric rodent species on seeds of oil tea ( Camellia oleifera) in Southwest China

    NASA Astrophysics Data System (ADS)

    Chang, Gang; Zhang, Zhibin

    2011-05-01

    Seed hoarding is an important behavioral adaptation to food shortages for many rodent species. Sympatric rodents may affect the natural regeneration of large-seeded trees differently as seed dispersers or seed predators. Using seeds of oil tea ( Camellia oleifera), we investigated differences in hoarding behaviors among six sympatric rodent species in semi-natural enclosures in a subtropical forest in southwest of China. We found that all these six species ate seeds of C. oleifera, but only Edward's long-tailed rats ( Leopoldamys edwardsi) were predominantly scatter hoarders; chestnut rats ( Niviventer fulvescens) and white-bellied rats ( Niviventer confucianus) scatter hoarded and larder hoarded few seeds, but were seed predators; South China field mice ( Apodemus draco) exhibited little larder-hoarding behavior; and Chevrier's field mice ( A. chevrieri) as well as Himalayan rats ( Rattus nitidusa) did not hoard seeds at all. The rodents that engaged in scatter hoarding often formed single-seed caches and tended to cache seeds under grass or shrubs. Our findings indicate that sympatric rodents consuming seeds of the same species of plant can have different hoarding strategies, affecting seed dispersal and plant regeneration differently. We conclude by discussing the role of these species in hoarding seeds of C. oleifera and highlight the essential role of Edward's long-tailed rats as predominantly potential dispersers of this plant species.

  6. REACTIVE OXYGEN SPECIES, ABA AND NITRIC OXIDE INTERACTIONS ON THE GERMINATION OF WARM-SEASON C4-GRASSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrogen peroxide (H2O2) significantly stimulated germination of switchgrass (Panicum virgatum L.) seeds with an optimal concentration of 20 mM at both 25°C and 35°C. For non-dormant switchgrass seeds exhibiting different levels of germination, treatment with H2O2 resulted in rapid germination (>3 d...

  7. Chemical composition and in vitro gas production of silage from guinea grass, cassava peel and cashew apple waste at different periods of ensilage.

    PubMed

    Dele, P A; Jolaosho, A O; Arigbede, O M; Ojo, V O A; Amole, T A; Okukenu, O A; Akinyemi, B T

    2013-12-01

    A study was carried out to determine the quality of silage produced from guinea grass, cassava peel and cashew apple waste at different ensiling periods. The materials were mixed into nine different proportions and ensiled for 30, 60 and 90 days making twenty-seven (27) treatments with each replicated three times. At the expiration of ensiling duration, the jars were opened, the contents were mixed, oven-dried and the proximate composition and fibre fractions were determined. The results showed that there were significant (p < 0.05) reduction in the Dry Matter (DM), Crude Protein (CP) and Neutral Detergent Fibre (NDF) with increase in ensiling duration while the Non Fibre Carbohydrate (NFC) increased with increased ensiling duration. The highest CP content (14.44%) was obtained in 25% Guinea Grass (GG)+25% cassava peel (CAP)+50% Cashew Apple Waste (CAW) which was not significantly (p > 0.05) different from 100% CAW. The NDF varied (p < 0.05) from 44.21 in 75% CAP+25% CAW silage to 60.31 in 100% GG. The reduction in the CP and NDF of the silage is still within the range required for growth and maintenance in ruminant animals. PMID:24506052

  8. Nutritive value and fermentation parameters of warm-season grass silage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to investigate the nutritive value and fermentation characteristics of different species of warm-season grass silages treated with or without bacterial inoculants in the summer and fall. Nine forage species and cultivars, elephantgrass (Pennisetum purpureum Schumach),...

  9. Method and device for identifying different species of honeybees

    DOEpatents

    Kerr, Howard T.; Buchanan, Michael E.; Valentine, Kenneth H.

    1989-01-01

    A method and device have been provided for distinguishing Africanized honeybees from European honeybees. The method is based on the discovery of a distinct difference in the acoustical signatures of these two species of honeybees in flight. The European honeybee signature has a fundamental power peak in the 210 to 240 Hz range while the Africanized honeybee signature has a fundamental power peak in the 260 to 290 Hz range. The acoustic signal produced by honeybees is analyzed by means of a detecting device to quickly determine the honeybee species through the detection of the presence of frequencies in one of these distinct ranges. The device includes a microphone for acoustical signal detection which feeds the detected signal into a frequency analyzer which is designed to detect the presence of either of the known fundamental wingbeat frequencies unique to the acoustical signatures of these species as an indication of the identity of the species and indicate the species identity on a readout device.

  10. Global Expression Patterns of Three Festuca Species Exposed to Different Doses of Glyphosate Using the Affymetrix GeneChip Wheat Genome Array

    PubMed Central

    Cebeci, Ozge; Budak, Hikmet

    2009-01-01

    Glyphosate has been shown to act as an inhibitor of an aromatic amino acid biosynthetic pathway, while other pathways that may be affected by glyphosate are not known. Cross species hybridizations can provide a tool for elucidating biological pathways conserved among organisms. Comparative genome analyses have indicated a high level of colinearity among grass species and Festuca, on which we focus here, and showed rearrangements common to the Pooideae family. Based on sequence conservation among grass species, we selected the Affymetrix GeneChip Wheat Genome Array as a tool for the analysis of expression profiles of three Festuca (fescue) species with distinctly different tolerances to varying levels of glyphosate. Differences in transcript expression were recorded upon foliar glyphosate application at 1.58 mM and 6.32 mM, representing 5% and 20%, respectively, of the recommended rate. Differences highlighted categories of general metabolic processes, such as photosynthesis, protein synthesis, stress responses, and a larger number of transcripts responded to 20% glyphosate application. Differential expression of genes encoding proteins involved in the shikimic acid pathway could not be identified by cross hybridization. Microarray data were confirmed by RT-PCR and qRT-PCR analyses. This is the first report to analyze the potential of cross species hybridization in Fescue species and the data and analyses will help extend our knowledge on the cellular processes affected by glyphosate. PMID:20182642

  11. Genome-Wide Transcriptional Profiling and Metabolic Analysis Uncover Multiple Molecular Responses of the Grass Species Lolium perenne Under Low-Intensity Xenobiotic Stress

    PubMed Central

    Serra, Anne-Antonella; Couée, Ivan; Heijnen, David; Michon-Coudouel, Sophie; Sulmon, Cécile; Gouesbet, Gwenola

    2015-01-01

    Lolium perenne, which is a major component of pastures, lawns, and grass strips, can be exposed to xenobiotic stresses due to diffuse and residual contaminations of soil. L. perenne was recently shown to undergo metabolic adjustments in response to sub-toxic levels of xenobiotics. To gain insight in such chemical stress responses, a de novo transcriptome analysis was carried out on leaves from plants subjected at the root level to low levels of xenobiotics, glyphosate, tebuconazole, and a combination of the two, leading to no adverse physiological effect. Chemical treatments influenced significantly the relative proportions of functional categories and of transcripts related to carbohydrate processes, to signaling, to protein-kinase cascades, such as Serine/Threonine-protein kinases, to transcriptional regulations, to responses to abiotic or biotic stimuli and to responses to phytohormones. Transcriptomics-based expressions of genes encoding different types of SNF1 (sucrose non-fermenting 1)-related kinases involved in sugar and stress signaling or encoding key metabolic enzymes were in line with specific qRT-PCR analysis or with the important metabolic and regulatory changes revealed by metabolomic analysis. The effects of pesticide treatments on metabolites and gene expression strongly suggest that pesticides at low levels, as single molecule or as mixture, affect cell signaling and functioning even in the absence of major physiological impact. This global analysis of L. perenne therefore highlighted the interactions between molecular regulation of responses to xenobiotics, and also carbohydrate dynamics, energy dysfunction, phytohormones and calcium signaling. PMID:26734031

  12. Quantitative analysis of diet structure by real-time PCR, reveals different feeding patterns by two dominant grasshopper species

    PubMed Central

    Huang, Xunbing; Wu, Huihui; McNeill, Mark Richard; Qin, Xinghu; Ma, Jingchuan; Tu, Xiongbing; Cao, Guangchun; Wang, Guangjun; Nong, Xiangqun; Zhang, Zehua

    2016-01-01

    Studies on grasshopper diets have historically employed a range of methodologies, each with certain advantages and disadvantages. For example, some methodologies are qualitative instead of quantitative. Others require long experimental periods or examine population-level effects, only. In this study, we used real-time PCR to examine diets of individual grasshoppers. The method has the advantage of being both fast and quantitative. Using two grasshopper species, Oedaleus asiaticus and Dasyhippus barbipes, we designed ITS primer sequences for their three main host plants, Stipa krylovii, Leymus chinensis and Cleistogenes squarrosa and used real-time PCR method to test diet structure both qualitatively and quantitatively. The lowest detection efficiency of the three grass species was ~80% with a strong correlation between actual and PCR-measured food intake. We found that Oedaleus asiaticus maintained an unchanged diet structure across grasslands with different grass communities. By comparison, Dasyhippus barbipes changed its diet structure. These results revealed why O. asiaticus distribution is mainly confined to Stipa-dominated grassland, and D. barbipes is more widely distributed across Inner Mongolia. Overall, real-time PCR was shown to be a useful tool for investigating grasshopper diets, which in turn offers some insight into grasshopper distributions and improved pest management. PMID:27562455

  13. Quantitative analysis of diet structure by real-time PCR, reveals different feeding patterns by two dominant grasshopper species.

    PubMed

    Huang, Xunbing; Wu, Huihui; McNeill, Mark Richard; Qin, Xinghu; Ma, Jingchuan; Tu, Xiongbing; Cao, Guangchun; Wang, Guangjun; Nong, Xiangqun; Zhang, Zehua

    2016-01-01

    Studies on grasshopper diets have historically employed a range of methodologies, each with certain advantages and disadvantages. For example, some methodologies are qualitative instead of quantitative. Others require long experimental periods or examine population-level effects, only. In this study, we used real-time PCR to examine diets of individual grasshoppers. The method has the advantage of being both fast and quantitative. Using two grasshopper species, Oedaleus asiaticus and Dasyhippus barbipes, we designed ITS primer sequences for their three main host plants, Stipa krylovii, Leymus chinensis and Cleistogenes squarrosa and used real-time PCR method to test diet structure both qualitatively and quantitatively. The lowest detection efficiency of the three grass species was ~80% with a strong correlation between actual and PCR-measured food intake. We found that Oedaleus asiaticus maintained an unchanged diet structure across grasslands with different grass communities. By comparison, Dasyhippus barbipes changed its diet structure. These results revealed why O. asiaticus distribution is mainly confined to Stipa-dominated grassland, and D. barbipes is more widely distributed across Inner Mongolia. Overall, real-time PCR was shown to be a useful tool for investigating grasshopper diets, which in turn offers some insight into grasshopper distributions and improved pest management. PMID:27562455

  14. The effect of seaweed Ecklonia maxima extract and mineral nitrogen on fodder grass chemical composition.

    PubMed

    Ciepiela, Grażyna Anna; Godlewska, Agnieszka; Jankowska, Jolanta

    2016-02-01

    The objective of this study was to determine the effect of the biostimulant Kelpak and different nitrogen rates on cellulose, hemicellulose and lignin contents as well as non-structural carbohydrates in orchard grass and Braun's festulolium. The experiment was a split-plot arrangement with three replicates. It was set up at the experimental facility of the University of Natural Sciences and Humanities, Siedlce, in late April 2009. The following factors were examined: biostimulant with the trade name Kelpak SL applied at 2 dm(3) ha(-1) and a control-no biostimulant; nitrogen application rates 50 and 150 kg ha(-1) and a control (0 kg ha(-1)); pure stands of grass species grown in monoculture--orchard grass (Dactylis glomerata), cv. Amila,-Braun's festulolium (Festulolium braunii), cv. Felopa. Kelpak significantly increased non-structural carbohydrates, and increasing nitrogen rates reduced the concentration of these components in plants. Increasing nitrogen rates significantly decreased cellulose, hemicellulose, lignin and non-structural carbohydrate contents. Compared with orchard grass, Braun's festulolium proved to be of a higher nutritional value due to lower cellulose, hemicellulose and lignin contents and more non-structural carbohydrates. The aforementioned contents in the grasses differed significantly depending on the cut. Most cellulose and non-structural carbohydrates were determined in second-cut grass whereas most hemicellulose and lignin in second-cut grass. PMID:26408121

  15. Production, Nutritional Quality and In vitro Methane Production from Andropogon gayanus Grass Harvested at Different Maturities and Preserved as Hay or Silage

    PubMed Central

    Ribeiro, G. O.; Teixeira, A. M.; Velasco, F. O.; Faria Júnior, W. G.; Pereira, L. G. R.; Chaves, A. V.; Gonçalves, L. C.; McAllister, T. A.

    2014-01-01

    Andropogon gayanus is an important grass due to its high biomass production, drought tolerance and favorable growth on low fertility acidic soils. Currently, there is little research on the impact of growth stage on the nutritional quality or the degree of CH4 production that may arise from this forage during ruminal fermentation. The objectives of this study were to determine the effects of regrowth stage of A. gayanus on its chemical composition, in vitro production of gas and CH4, as well as in vitro dry matter (DM) digestibility when grown under tropical Brazilian conditions and conserved as hay or as silage. The nutritional value of A. gayanus grass declined with increasing maturity; however digestible DM yield linearly increased. After 112 d of regrowth, A. gayanus produced higher quality silage (higher lactate and lower pH and butyrate content) and higher DM yield. However, the low levels of crude protein at this time would make protein supplementation a necessity for proper rumen fermentation. No differences in CH4 kinetic parameters were found with advancing maturity or preservation method (hay or silage). PMID:25049959

  16. Bovine-associated CNS species resist phagocytosis differently

    PubMed Central

    2013-01-01

    Background Coagulase-negative staphylococci (CNS) cause usually subclinical or mild clinical bovine mastitis, which often remains persistent. Symptoms are usually mild, mostly only comprising slight changes in the appearance of milk and possibly slight swelling. However, clinical mastitis with severe signs has also been reported. The reasons for the differences in clinical expression are largely unknown. Macrophages play an important role in the innate immunity of the udder. This study examined phagocytosis and killing by mouse macrophage cells of three CNS species: Staphylococcus chromogenes (15 isolates), Staphylococcus agnetis (6 isolates) and Staphylococcus simulans (15 isolates). Staphylococcus aureus (7 isolates) was also included as a control. Results All the studied CNS species were phagocytosed by macrophages, but S. simulans resisted phagocytosis more effectively than the other CNS species. Only S. chromogenes was substantially killed by macrophages. Significant variations between isolates were seen in both phagocytosis and killing by macrophages and were more common in the killing assays. Significant differences between single CNS species and S. aureus were observed in both assays. Conclusion This study demonstrated that differences in the phagocytosis and killing of mastitis-causing staphylococci by macrophages exist at both the species and isolate level. PMID:24207012

  17. Species composition and abundance of Brevipalpus spp. on different citrus species in Mexican orchards.

    PubMed

    Salinas-Vargas, D; Santillán-Galicia, M T; Valdez-Carrasco, J; Mora-Aguilera, G; Atanacio-Serrano, Y; Romero-Pescador, P

    2013-08-01

    We studied the abundance of Brevipalpus spp. in citrus orchards in the Mexican states of Yucatan, Quintana Roo and Campeche. Mites were collected from 100 trees containing a mixture of citrus species where sweet orange was always the main species. Eight collections were made at each location from February 2010 to February 2011. Mites from the genus Brevipalpus were separated from other mites surveyed and their abundance and relationships with the different citrus species were quantified throughout the collection period. A subsample of 25% of the total Brevipalpus mites collected were identified to species level and the interaction of mite species and citrus species were described. Brevipalpus spp. were present on all collection dates and their relative abundance was similar on all citrus species studies. The smallest number of mites collected was during the rainy season. Brevipalpus phoenicis (Geijskes) and Brevipalpus californicus (Banks) were the only two species present and they were found in all locations except Campeche, where only B. phoenicis was present. Yucatan and Campeche are at greater risk of leprosis virus transmission than Quintana Roo because the main vector, B. phoenicis, was more abundant than B. californicus. The implications of our results for the design of more accurate sampling and control methods for Brevipalpus spp. are discussed. PMID:23949863

  18. Local versus landscape-scale effects of savanna trees on grasses

    USGS Publications Warehouse

    Riginos, C.; Grace, J.B.; Augustine, D.J.; Young, T.P.

    2009-01-01

    1. Savanna ecosystems - defined by the coexistence of trees and grasses - cover more than one-fifth the world's land surface and harbour most of the world's rangelands, livestock and large mammal diversity. Savanna trees can have a variety of effects on grasses, with consequences for the wild and domestic herbivores that depend on them. 2.Studies of these effects have focused on two different spatial scales. At the scale of individual trees, many studies have shown net positive effects of trees on sub-canopy grass nutrient concentrations and biomass. At the landscape scale, other studies have shown negative effects of high tree densities on grass productivity. These disparate results have led to different conclusions about the effects of trees on forage quality and ungulate nutrition in savannas. 3.We integrate these approaches by examining the effects of trees on grasses at both spatial scales and across a range of landscape-scale tree densities. 4.We quantified grass biomass, species composition and nutrient concentrations in these different contexts in an Acacia drepanolobium savanna in Laikipia, Kenya. Individual trees had positive effects on grass biomass, most likely because trees enrich soil nitrogen. Grass leaf phosphorus in sub-canopy areas, however, was depressed. The effects of individual trees could explain the effects of increasing landscape-scale tree cover for the biomass of only two of the four dominant grass species. 5.The negative effects of trees on grass and soil phosphorus, combined with depressed grass productivity in areas of high tree cover, suggest that ungulate nutrition may be compromised in areas with many trees. 6.Synthesis. We conclude that few, isolated trees may have positive local effects on savanna grasses and forage, but in areas of high tree density the negative landscape-scale effects of trees are likely to outweigh these positive effects. In savannas and other patchy landscapes, attempts to predict the consequences of changes

  19. [Quality survey of different species of clematidis radix et rhizoma].

    PubMed

    Li, Qian-Qian; Ma, Chang-Hua; Liu, Chun-Sheng; Xiao, Yao; Chen, Mei-Lan; Tian, Zhi-Hao; Wang, Yuan; Kong, Fan-Yao; Xu, Wen-Ying

    2013-04-01

    Quality survey of different species of Clematidis Radix et Rhizoma was made by determining the content of hederagenin and oleanolic acid from Clematidis Radix et Rhizoma. The result showed that only a few samples of Clematis chinensis met the quality standard for Clematidis Radix et Rhizoma in Chinese Pharmacopoeia 2010 Edition. PMID:23944036

  20. Comparative proteomic analysis of developing rhizomes of the ancient vascular plant Equisetum hyemale and different monocot species.

    PubMed

    Salvato, Fernanda; Balbuena, Tiago S; Nelson, William; Rao, R Shyama Prasad; He, Ruifeng; Soderlund, Carol A; Gang, David R; Thelen, Jay J

    2015-04-01

    The rhizome is responsible for the invasiveness and competitiveness of many plants with great economic and agricultural impact worldwide. Besides its value as an invasive organ, the rhizome plays a role in the establishment and massive growth of forage, providing biomass for biofuel production. Despite these features, little is known about the molecular mechanisms that contribute to rhizome growth, development, and function in plants. In this work, we characterized the proteome of rhizome apical tips and elongation zones from different species using a GeLC-MS/MS (one-dimensional electrophoresis in combination with liquid chromatography coupled online with tandem mass spectrometry) spectral-counting proteomics strategy. Five rhizomatous grasses and an ancient species were compared to study the protein regulation in rhizomes. An average of 2200 rhizome proteins per species were confidently identified and quantified. Rhizome-characteristic proteins showed similar functional distributions across all species analyzed. The over-representation of proteins associated with central roles in cellular, metabolic, and developmental processes indicated accelerated metabolism in growing rhizomes. Moreover, 61 rhizome-characteristic proteins appeared to be regulated similarly among analyzed plants. In addition, 36 showed conserved regulation between rhizome apical tips and elongation zones across species. These proteins were preferentially expressed in rhizome tissues regardless of the species analyzed, making them interesting candidates for more detailed investigative studies about their roles in rhizome development. PMID:25716083

  1. Genetic variations of body weight and GCRV resistance in a random mating population of grass carp

    PubMed Central

    Huang, Rong; Sun, Jiaxian; Luo, Qing; He, Libo; Liao, Lanjie; Li, Yongming; Guo, Fuhua; Zhu, Zuoyan; Wang, Yaping

    2015-01-01

    The grass carp (Ctenopharyngodon idellus) is an important species in freshwater aquaculture both in China and on a global scale. Variety degeneration and frequent diseases have limited the further development of grass carp aquaculture. Thus, new and improved varieties are required. Here, we identified and assessed the body weight and disease resistance in a random mating population of 19 ♀ × 22 ♂ grass carp, which were derived from different water systems. In both the growth experimental group of 10,245 fish and grass carp reovirus (GCRV)-infected group with 10,000 fish, 78 full-sib families were statistically analyzed for body weight and GCRV resistance. The findings showed that body weight traits had low heritability (0.11 ± 0.04, 0.10 ± 0.03 and 0.12 ± 0.05), GCRV resistance traits had high heritability (0.63 ± 0.11); body weight was higher in 3 families, whereas GCRV resistance was significantly greater in 11 families. Our results confirmed that the natural germplasm resources of wild grass carp were genetically diverse. Breeding of GCRV resistant varieties of grass carp have better genetic basis. This study provides the basis for constructing basal populations for grass carp selective breeding, quantitative trait loci (QTL) and genome-wide association studies (GWAS) analysis. PMID:26439690

  2. Checklist of Serengeti Ecosystem Grasses

    PubMed Central

    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

  3. Checklist of Serengeti Ecosystem Grasses.

    PubMed

    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. PMID:27226761

  4. Brain organization of gorillas reflects species differences in ecology.

    PubMed

    Barks, Sarah K; Calhoun, Michael E; Hopkins, William D; Cranfield, Michael R; Mudakikwa, Antoine; Stoinski, Tara S; Patterson, Francine G; Erwin, Joseph M; Hecht, Erin E; Hof, Patrick R; Sherwood, Chet C

    2015-02-01

    Gorillas include separate eastern (Gorilla beringei) and western (Gorilla gorilla) African species that diverged from each other approximately 2 million years ago. Although anatomical, genetic, behavioral, and socioecological differences have been noted among gorilla populations, little is known about variation in their brain structure. This study examines neuroanatomical variation between gorilla species using structural neuroimaging. Postmortem magnetic resonance images were obtained of brains from 18 captive western lowland gorillas (Gorilla gorilla gorilla), 15 wild mountain gorillas (Gorilla beringei beringei), and 3 Grauer's gorillas (Gorilla beringei graueri) (both wild and captive). Stereologic methods were used to measure volumes of brain structures, including left and right frontal lobe gray and white matter, temporal lobe gray and white matter, parietal and occipital lobes gray and white matter, insular gray matter, hippocampus, striatum, thalamus, each hemisphere and the vermis of the cerebellum, and the external and extreme capsules together with the claustrum. Among the species differences, the volumes of the hippocampus and cerebellum were significantly larger in G. gorilla than G. beringei. These anatomical differences may relate to divergent ecological adaptations of the two species. Specifically, G. gorilla engages in more arboreal locomotion and thus may rely more on cerebellar circuits. In addition, they tend to eat more fruit and have larger home ranges and consequently might depend more on spatial mapping functions of the hippocampus. PMID:25360547

  5. Species differences and molecular determinant of TRPA1 cold sensitivity

    PubMed Central

    Chen, Jun; Kang, Dawon; Xu, Jing; Lake, Marc; Hogan, James O.; Sun, Chaohong; Walter, Karl; Yao, Betty; Kim, Donghee

    2013-01-01

    TRPA1 is an ion channel and has been proposed as a thermosensor across species. In invertebrate and ancestral vertebrates such as fly, mosquito, frog, lizard and snakes, TRPA1 serves as a heat receptor, a sensory input utilized for heat avoidance or infrared detection. However, in mammals, whether TRPA1 is a receptor for noxious cold is highly controversial, as channel activation by cold was observed by some groups but disputed by others. Here we attribute the discrepancy to species differences. We show that cold activates rat and mouse TRPA1 but not human or rhesus monkey TRPA1. At the molecular level, a single residue within the S5 transmembrane domain (G878 in rodent but V875 in primate) accounts for the observed difference in cold sensitivity. This residue difference also underlies the species-specific effects of menthol. Together, our findings identify the species-specific cold activation of TRPA1 and reveal a molecular determinant of cold-sensitive gating. PMID:24071625

  6. Brain organization of gorillas reflects species differences in ecology

    PubMed Central

    Barks, Sarah K.; Calhoun, Michael E.; Hopkins, William D.; Cranfield, Michael R.; Mudakikwa, Antoine; Stoinski, Tara S.; Patterson, Francine G.; Erwin, Joseph M.; Hecht, Erin E.; Hof, Patrick R.; Sherwood, Chet C.

    2014-01-01

    Gorillas include separate eastern (Gorilla beringei) and western (Gorilla gorilla) African species that diverged from each other approximately 2 million years ago. Although anatomical, genetic, behavioral, and socioecological differences have been noted among gorilla populations, little is known about variation in their brain structure. This study examines neuroanatomical variation between gorilla species using structural neuroimaging. Postmortem magnetic resonance images were obtained of brains from 18 captive western lowland gorillas (Gorilla gorilla gorilla), 15 wild mountain gorillas (Gorilla beringei beringei), and 3 Grauer's gorillas (Gorilla beringei graueri) (both wild and captive). Stereologic methods were used to measure volumes of brain structures, including left and right frontal lobe gray and white matter, temporal lobe gray and white matter, parietal and occipital lobes gray and white matter, insular gray matter, hippocampus, striatum, thalamus, each hemisphere and the vermis of the cerebellum, and the external and extreme capsules together with the claustrum. Among the species differences, the volumes of the hippocampus and cerebellum were significantly larger in G. gorilla than G. beringei. These anatomical differences may relate to divergent ecological adaptations of the two species. Specifically, G. gorilla engage in more arboreal locomotion and thus may rely more on cerebellar circuits. In addition, they tend to eat more fruit and have larger home ranges and consequently might depend more on spatial mapping functions of the hippocampus. PMID:25360547

  7. Four pathogenic Candida species differ in salt tolerance.

    PubMed

    Krauke, Yannick; Sychrova, Hana

    2010-10-01

    The virulence of Candida species depends on many environmental conditions, including extracellular pH and concentration of alkali metal cations. Tests of the tolerance/sensitivity of four pathogenic Candida species (C. albicans, C. dubliniensis, C. glabrata, and C. parapsilosis) to alkali metal cations under various growth conditions revealed significant differences among these species. Though all of them can be classified as rather osmotolerant yeast species, they exhibit different levels of tolerance to different salts. C. parapsilosis and C. albicans are the most salt-tolerant in general; C. dubliniensis is the least tolerant on rich YPD media and C. glabrata on acidic (pH 3.5) minimal YNB medium. C. dubliniensis is relatively salt-sensitive in spite of its ability to maintain as high intracellular K(+)/Na(+) ratio as its highly salt-tolerant relative C. albicans. On the other hand, C. parapsilosis can grow in the presence of very high external NaCl concentrations in spite of its high intracellular Na(+) concentrations (and thus lower K(+)/Na(+) ratio) and thus resembles salt-tolerant (halophilic) Debaryomyces hansenii. PMID:20300937

  8. Fusarium dactylidis sp. nov., a novel nivalenol toxin-producing species sister to F. pseudograminearum isolated from orchard grass (Dactylis glomerata) in Oregon and New Zealand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The B trichothecene toxin-producing clade (B clade) of Fusarium includes the etiological agents of Fusarium head blight, crown rot of wheat and barley and stem and ear rot of maize. B clade isolates also have been recovered from several wild and cultivated grasses, including Dactylis glomerata (orch...

  9. Response of dominant grass and shrub species to water manipulation: an ecophysiological basis for shrub invasion in a Chihuahuan Desert grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  10. Possible difference in glycosylation of the thyrotropin receptor among species.

    PubMed

    Kosugi, S; Akamizu, T; Mori, T

    1994-05-16

    Residue 113 of the thyrotropin receptor (TSHR) is a possible asparagine-linked glycosylation site in the human TSHR, but not in rat or dog TSHR. Russo et al. (Mol Endocrinol 5:29-33) reported that mutation of this residue in the human TSHR diminished TSH binding activity after transfection. To investigate the difference in the role of residue 113 of the TSHR among species, we created a mutant at residue 113 in the rat TSHR, transfected Cos-7 cells with the mutant DNA and measured TSH binding and TSH- and Graves' IgG-stimulated cAMP and phosphoinositide signals. No difference was found in the activities of the mutant transfectant from the wild type receptor transfectant. These results might suggest a real difference in glycosylation of the TSHR among species. PMID:8185569

  11. Similarities and differences in rubber biochemistry among plant species.

    PubMed

    Cornish, K

    2001-08-01

    This report reviews aspects of the biochemical regulation of rubber yield and rubber quality in three contrasting rubber-producing species, Hevea brasiliensis, Parthenium argentatum and Ficus elastica. Although many similarities are revealed, considerable differences also exist in enzymatic mechanisms regulating biosynthetic rate and the molecular weight of the rubber biopolymers produced. In all three species, rubber molecule initiation, biosynthetic rate and molecular weight, in vitro, are dependent upon substrate concentration and the ratio of isopentenyl pyrophosphate (IPP, the elongation substrate, or monomer) and farnesyl pyrophosphate (FPP, an initiator), but these parameters are affected by intrinsic properties of the rubber transferases as well. All three rubber transferases are capable of producing a wide range of rubber molecular weight, depending upon substrate concentration, clearly demonstrating that the transferases are not the prime determinants of product size in vivo. However, despite these commonalities, considerable differences exist between the species with respect to cosubstrate effects, binding constants, effective concentration ranges, and the role of negative cooperativity in vitro. The P. argentatum rubber transferase appears to exert more control over the molecular weight it produces than the other two species and may, therefore, provide the best prospect for the source of genes for transformation of annual crop species. The kinetic data, from the three contrasting rubber-producing species, also were used to develop a model of the rubber transferase active site in which, in addition to separate IPP and allylic-PP binding sites, there exists a hydrophobic region that interacts with the linear portion of allylic-PP initiator proximal to the pyrophosphate. Substrate affinity increases until the active site is traversed and the rubber interior of the rubber particle is reached. The kinetic data suggest that the hydrophobic region in H

  12. Method and device for identifying different species of honeybees

    SciTech Connect

    Kerr, H.T.; Buchanan, M.E.; Valentine, K.H.

    1989-10-24

    A method and device have been provided for distinguishing Africanized honeybees from European honeybees. The method is based on the discovery of a distinct difference in the acoustical signatures of these two species of honeybees in flight. The European honeybee signature has a fundamental power peak in the 210 to 240 Hz range while the Africanized honeybee signature has a fundamental power peak in the 260 to 290 Hz range. The acoustic signal produced by honeybees is analyzed by means of a detecting device to quickly determine the honeybee species through the detection of the presence of frequencies in one of these distinct ranges. The device includes a microphone for acoustical signal detection which feeds the detected signal into a frequency analyzer which is designed to detect the presence of either of the known fundamental wingbeat frequencies unique to the acoustical signatures of these species as an indication of the identity of the species and indicate the species identity on a readout device. 8 figs.

  13. Plant response to aqueous effluents derived from in-situ fossil-fuel processing. Part II. Five grass plant species and their response to five produced retort waters: oil shale, tar sands, and underground coal gasification. [Wildrye; wheatgrass; alkali sacaton; alkaligrass

    SciTech Connect

    Skinner, Q.D.

    1981-11-01

    In situ produced waters collected from retorting oil shale and tar sands to produce oil and in-situ coal gasification to produce gas were tested for their effect on plant growth. Five native grass plant species were utilized for monitoring growth response. Root weight, shoot weight, total dry weight, leaf area, root/shoot ratio and shoot/leaf area ratio were parameters measured. All experiments were conducted under greenhouse conditions using hydroponic techniques and commercial grade perlite as support systems. Measurements were collected after a 10 week growth period. Hypotheses tested were: (a) there is a difference between in situ produced waters, and (b) plant species respond differently to various retort waters. Results indicated that the stated hypotheses were true.

  14. Comparative study on sound production in different Holocentridae species

    PubMed Central

    2011-01-01

    Background Holocentrids (squirrelfish and soldierfish) are vocal reef fishes whose calls and sound-producing mechanisms have been studied in some species only. The present study aims to compare sound-producing mechanisms in different Holocentridae genera (Holocentrus, Myripristis, Neoniphon, Sargocentron) from separate regions and, in some cases, at different developmental stages. An accurate comparison was made by recording six species while being hand-held, by observing TEM) the sonic muscles and by dissections of the sound-producing mechanism. Results In all these species, calls presented harmonics, their dominant frequency was between 80 and 130 Hz and they were composed of trains of 4 to 11 pulses with gradual increasing periods towards the end of the call. In each case, the calls did not provide reliable information on fish size. The sounds were produced by homologous fast-contracting sonic muscles that insert on articulated ribs whose proximal heads are integrated into the swimbladder: each pulse is the result of the back and forth movements of the ribs. Small differences in the shape of the oscillograms of the different species could be related to the number of ribs that are involved in the sound-producing mechanism. These fish species are able to make sounds as soon as they settle on the reef, when they are 40 days old. Comparison between Neoniphon from Madagascar and from Rangiroa in French Polynesia showed a new, unexpected kind of dialect involving differences at the level of pulse distribution. Neoniphon calls were characterised by a single pulse that was isolated at the beginning of the remaining train in Madagascar whereas they did not show any isolated single pulses at the beginning of the call in Rangiroa. Conclusion This family cannot use the acoustic fundamental frequencies (or pulse periods) of grunts to infer the size of partners. Pulse duration and number of pulses are statistically related to fish size. However, these characteristics are

  15. Temporal changes of soil respiration under different tree species.

    PubMed

    Akburak, Serdar; Makineci, Ender

    2013-04-01

    Soil respiration rates were measured monthly (from April 2007 to March 2008) under four adjacent coniferous plantation sites [Oriental spruce (Picea orientalis L.), Austrian pine (Pinus nigra Arnold), Turkish fir (Abies bornmulleriana L.), and Scots pine (Pinus sylvestris L.)] and adjacent natural Sessile oak forest (Quercus petraea L.) in Belgrad Forest-Istanbul/Turkey. Also, soil moisture, soil temperature, and fine root biomass were determined to identify the underlying environmental variables among sites which are most likely causing differences in soil respiration. Mean annual soil moisture was determined to be between 6.3 % and 8.1 %, and mean annual temperature ranged from 13.0°C to 14.2°C under all species. Mean annual fine root biomass changed between 368.09 g/m(2) and 883.71 g/m(2) indicating significant differences among species. Except May 2007, monthly soil respiration rates show significantly difference among species. However, focusing on tree species, differences of mean annual respiration rates did not differ significantly. Mean annual soil respiration ranged from 0.56 to 1.09 g C/m(2)/day. The highest rates of soil respiration reached on autumn months and the lowest rates were determined on summer season. Soil temperature, soil moisture, and fine root biomass explain mean annual soil respiration rates at the highest under Austrian pine (R (2) = 0.562) and the lowest (R (2) = 0.223) under Turkish fir. PMID:22828980

  16. Differences in Time until Dispersal between Cryptic Species of a Marine Nematode Species Complex

    PubMed Central

    De Meester, Nele; Derycke, Sofie; Moens, Tom

    2012-01-01

    Co-occurrence of closely related species may be achieved in environments with fluctuating dynamics, where competitively inferior species can avoid competition through dispersal. Here we present an experiment in which we compared active dispersal abilities (time until first dispersal, number and gender of dispersive adults, and nematode densities at time of dispersal) in Litoditis marina, a common bacterivorous nematode species complex comprising four often co-occurring cryptic species, Pm I, II, III, and IV, as a function of salinity and food distribution. The experiment was conducted in microcosms consisting of an inoculation plate, connection tube, and dispersal plate. Results show species-specific dispersal abilities with Pm I dispersing almost one week later than Pm III. The number of dispersive adults at time of first dispersal was species-specific, with one dispersive female in Pm I and Pm III and a higher, gender-balanced, number in Pm II and Pm IV. Food distribution affected dispersal: in absence of food in the inoculation plate, all species dispersed after ca four days. When food was available Pm I dispersed later, and at the same time and densities irrespective of food conditions in the dispersal plate (food vs no food), suggesting density-dependent dispersal. Pm III dispersed faster and at a lower population density. Salinity affected dispersal, with slower dispersal at higher salinity. These results suggest that active dispersal in Litoditis marina is common, density-dependent, and with species, gender- and environment-specific dispersal abilities. These differences can lead to differential responses under suboptimal conditions and may help to explain temporary coexistence at local scales. PMID:22876328

  17. Can species-specific differences in foliar chemistry influence leaf litter decomposition in grassland species?

    NASA Astrophysics Data System (ADS)

    Sanaullah, M.; Chabbi, A.; Rumpel, C.

    2009-04-01

    The influence of litter quality on its rate of decomposition is a crucial aspect of C cycle. In this study we concentrated on grassland ecosystems where leaf litter is one of the major sources of C input. To quantify the contribution of initial leaf chemistry within different plant species, the decomposition of chemically different leaf litter of three grassland species (Lolium perenne, Festuca arundinacea and Dactylis glomerata) was monitored, using the litter bag technique. Litter of different maturity stages i.e. green (fresh leaves) and brown litter (brown leaves were still attached to the plant), were incubated on bare soil surface. Samples were taken at different time intervals (0, 2, 4, 8, 20 and 44 weeks) and were analyzed for mass loss, organic C and N contents and stable isotopic signatures (C and N). Changes in litter chemistry were addressed by determining lignin-derived phenols after CuO oxidation and non-cellulosic polysaccharides after acid hydrolysis followed by gas chromatography. Green litter was chemically different from brown litter due to higher initial N and lower lignin contents. While in grassland species, both L. perenne and D. glomerata were similar in their initial chemical composition compared with F. arundinacea. Green litter showed higher rate of degradation. In green litter, Percent lignin remaining of initial (% OI) followed the similar decomposition pattern as of C remaining indicating lignin as controlling factor in decomposition. Constant Acid-to-Aldehyde ratios of lignin-derived phenols (vanillyl and syringyl) did not suggest any transformation in lignin structures. In green litter, increase in non-cellulosic polysaccharides ratios (C6/C5 and deoxy/C5) proposed microbial-derived sugars, while there was no significant increase in these ratios in brown litter. In conclusion, due to the differences in initial chemical composition (initial N and lignin contents), green litter decomposition was higher than brown litter in all

  18. Germination sensitivities to water potential among co-existing C3 and C4 grasses of cool semi-arid prairie grasslands.

    PubMed

    Mollard, F P O; Naeth, M A

    2015-03-01

    An untested theory states that C4 grass seeds could germinate under lower water potentials (Ψ) than C3 grass seeds. We used hydrotime modelling to study seed water relations of C4 and C3 Canadian prairie grasses to address Ψ divergent sensitivities and germination strategies along a risk-spreading continuum of responses to limited water. C4 grasses were Bouteloua gracilis, Calamovilfa longifolia and Schizachyrium scoparium; C3 grasses were Bromus carinatus, Elymus trachycaulus, Festuca hallii and Koeleria macrantha. Hydrotime parameters were obtained after incubation of non-dormant seeds under different Ψ PEG 6000 solutions. A t-test between C3 and C4 grasses did not find statistical differences in population mean base Ψ (Ψb (50)). We found idiosyncratic responses of C4 grasses along the risk-spreading continuum. B. gracilis showed a risk-taker strategy of a species able to quickly germinate in a dry soil due to its low Ψb (50) and hydrotime (θH ). The high Ψb (50) of S. scoparium indicates it follows the risk-averse strategy so it can only germinate in wet soils. C. longifolia showed an intermediate strategy: the lowest Ψb (50) yet the highest θH . K. macrantha, a C3 grass which thrives in dry habitats, had the highest Ψb (50), suggesting a risk-averse strategy for a C3 species. Other C3 species showed intermediate germination patterns in response to Ψ relative to C4 species. Our results indicate that grasses display germination sensitivities to Ψ across the risk-spreading continuum of responses. Thus seed water relations may be poor predictors to explain differential recruitment and distribution of C3 and C4 grasses in the Canadian prairies. PMID:25580949

  19. Biochemistry of photosynthesis in species of triticum of differing ploidy.

    PubMed

    Holbrook, G P; Keys, A J; Leech, R M

    1984-01-01

    Illuminated flag leaves of Triticum monococcum(2X), T. urartu(2X), T. dicoccum(4X), T. dicoccoides(4X), and T. aestivum(6X) were exposed to (14)CO(2) for 10 seconds and subsequently allowed to continue photosynthesis in the ambient air for periods of up to 2 minutes. The relative distribution of (14)C among water-soluble products in the leaves was similar for each species at each sampling time. After the 10-second pulse of (14)CO(2), radioactivity was mainly in phosphate esters with less than 5% in C(4) acids. Subsequently, radioactivity increased in sucrose, glycine, and serine at the expense of that in phosphate esters. By 2 minutes, between 18% and 29% of the (14)C was in glycine plus serine. The results suggest rapid photorespiration in all species and an absence of C(4) photosynthesis.d-Ribulose 1,5-bisphosphate carboxylase (EC 4.1.1.39) was partly purified from seedling leaves of each of the five Triticum species. Each preparation was assayed for simultaneous carboxylase and oxygenase activities in 2.1 millimolar NaHCO(3) and 265 micromolar O(2) at pH 8.2 and 25 degrees C. The mean ratio of carboxylase to oxygenase activities was 6.11 +/- 0.16 (standard error); differences between values for different species were not statistically significant. The results do not explain the faster rates of photosynthesis per unit leaf area reported for diploid and tetraploid species of Triticum compared to the hexaploid. PMID:16663364

  20. Plasticity of nitrogen allocation in the leaves of the invasive wetland grass, Phalaris arundinacea and co-occurring Carex species determines the photosynthetic sensitivity to nitrogen availability.

    PubMed

    Holaday, A Scott; Schwilk, Dylan W; Waring, Elizabeth F; Guvvala, Hasitha; Griffin, Chelsea M; Lewis, O Milo

    2015-04-01

    Phalaris arundinacea displaces the slower-growing, native sedge, Carex stricta, where nitrogen availability is high. Our aim was to address whether morphological and physiological traits associated with carbon gain for P. arundinacea and C. stricta responded to nitrogen supply differently and if the species exhibited different degrees of plasticity in these traits. The plants were grown in gravel and provided modified Hoagland's solution containing four nitrogen concentrations from 0.15 to 15 mM for 6 to 7 weeks. Supplied nitrogen affected the leaf nitrogen content to the same degree for both species. Increasing supplied nitrogen strongly increased CO2 assimilation (A), photosynthetic nitrogen use efficiency (PNUE), and respiration for P. arundinacea but had only a small effect on these parameters for C. stricta. Relative to growth at 15 mM nitrogen, growth at 0.15 mM for young leaves decreased carboxylation capacity and efficiency and the capacity for electron transport for P. arundinacea and a larger, stouter Carex species, Carex lacustris, by 53 to 70% but only 20 to 24% for C. stricta. Leaf nitrogen decreased approximately 50% for all species, but vacuolar nitrate did not decrease for P. arundinacea and C. stricta, suggesting that it does not serve as a nitrogen reserve for use during nitrogen deprivation in these species. After 4 months of nitrogen deprivation, P. arundinacea doubled A in 12 days after being supplied 15 mM nitrogen, whereas A for C. stricta increased only 22%. We propose that one factor linking P. arundinacea abundance to nitrogen availability involves this species' plastic response of carbon gain to nitrogen supply. C. stricta appears to be adapted to tolerate low nitrogen availability but cannot respond as rapidly and extensively as P. arundinacea when nitrogen supply is high. PMID:25659333

  1. Ecological rehabilitation and phytoremediation with four grasses in oil shale mined land.

    PubMed

    Xia, H P

    2004-01-01

    Vetiver grass (Vetiveria zizanioides), bahia grass (Paspalum notatum), St. Augustine grass (Stenotaphrum secundatum), and bana grass (Pennisetum glaucumxP. purpureum) were selected to rehabilitate the degraded ecosystem of an oil shale mined land of Maoming Petro-Chemical Company located in Southwest of Guangdong Province, China. Among them, vetiver had the highest survival rate, up to 99%, followed by bahia and St. Augustine, 96% and 91%, respectively, whereas bana had the lowest survival rate of 62%. The coverage and biomass of vetiver were also the highest after 6-month planting. Fertilizer application significantly increased biomass and tiller number of the four grasses, of which St. Augustine was promoted most, up to 70% for biomass, while vetiver was promoted least, only 27% for biomass. Two heavy metals, lead (Pb) and cadmium (Cd) tested in this trial had different concentrations in the oil shale residue, and also had different contents and distributions in the four grass species. Concentrations of Pb and Cd in the four grasses presented a disparity of only 1.6-3.8 times, but their uptake amounts to the two metals were apart up to 27.5-35.5 times, which was chiefly due to the significantly different biomasses among them. Fertilizer application could abate the ability of the four species to accumulate heavy metals, namely concentration of heavy metals in plants decreased as fertilizer was applied. The total amount of metals accumulated by each plant under the condition of fertilization did not decrease due to an increase of biomass. In summary, vetiver may be the best species used for vegetation rehabilitation in oil shale disposal piles. PMID:14575747

  2. Unique aspects of the grass cell wall

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grasses are amongst the most important crops worldwide, and the composition of their cell walls is critical for uses as food, feed, and energy crops. Grass cell walls differ dramatically from dicot cell walls in terms of the major structural polysaccharides present, how those polysaccharides are lin...

  3. Preferences of different tick species for human hosts in Turkey.

    PubMed

    Kar, S; Dervis, E; Akın, A; Ergonul, O; Gargili, A

    2013-11-01

    The ticks removed from the patients who applied to the hospitals in Istanbul and neighboring cities, Turkey, with the complaint of tick bite were examined in this study, on account of their species, biological stages, attachment sites on the body, and the age of the affected patients. A total of 16,969 ticks were identified. Encountered species were as follows: 33.6 % Ixodes spp. immature, 25.3 % Hyalomma spp. immature, 24.3 % I. ricinus, 9.5 % Rhipicephalus sanguineus gr., 3.2 % R. bursa, 2.2 % Hyalomma marginatum, 1.96 % Haemaphysalis adults, 1.66 % Hyalomma aegyptium, 0.52 % Dermacentor marginatus, 0.39 % Rhipicephalus spp. nymphs, 0.12 % Dermacentor spp. nymphs, 0.11 % Haemaphysalis spp. nymphs, 0.09 % Hyalomma scupense, and 0.03 % Hyalomma excavatum. The distribution of attachment sites of the species and instars showed significant differences. Furthermore, age data of the patients also revealed that certain tick species were more common within certain age groups. PMID:23620419

  4. Differences in trophic position among sympatric sea urchin species

    NASA Astrophysics Data System (ADS)

    Vanderklift, Mathew A.; Kendrick, Gary A.; Smit, Albertus J.

    2006-01-01

    Three species of sea urchin regularly co-occur in high abundances on subtidal rocky reefs in south-western Australia. We used two lines of evidence (stable isotope analysis and gut contents analysis), to test whether these species occupy different trophic positions. We looked at five discrete populations to test whether patterns were consistent. The gut contents of Heliocidaris erythrogramma contained almost exclusively fragments of macroalgae, and the δ15N of muscle was consistent with that expected for a herbivore. In contrast, the gut contents of Phyllacanthus irregularis and Centrostephanus tenuispinus contained a greater proportion of animal tissue, and the δ15N of muscle suggested that animal tissue was an important source of nutrition. Of the three co-occurring sea urchin species, one ( H. erythrogramma) was ecologically dissimilar to the others and occupied a lower trophic position. This pattern was consistent among populations separated by up to 270 km in south-western Australia. Food resource partitioning might be one way in which these species are able to coexist.

  5. Sonoran Desert ecosystem transformation by a C4 grass without the grass/fire cycle

    USGS Publications Warehouse

    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

  6. DNA repair in species with extreme lifespan differences

    PubMed Central

    MacRae, Sheila L.; Croken, Matthew McKnight; Calder, R.B.; Aliper, Alexander; Milholland, Brandon; White, Ryan R.; Zhavoronkov, Alexander; Gladyshev, Vadim N.; Seluanov, Andrei; Gorbunova, Vera; Zhang, Zhengdong D.; Vijg, Jan

    2015-01-01

    Differences in DNA repair capacity have been hypothesized to underlie the great range of maximum lifespans among mammals. However, measurements of individual DNA repair activities in cells and animals have not substantiated such a relationship because utilization of repair pathways among animals—depending on habitats, anatomical characteristics, and life styles—varies greatly between mammalian species. Recent advances in high-throughput genomics, in combination with increased knowledge of the genetic pathways involved in genome maintenance, now enable a comprehensive comparison of DNA repair transcriptomes in animal species with extreme lifespan differences. Here we compare transcriptomes of liver, an organ with high oxidative metabolism and abundant spontaneous DNA damage, from humans, naked mole rats, and mice, with maximum lifespans of ∼120, 30, and 3 years, respectively, with a focus on genes involved in DNA repair. The results show that the longer-lived species, human and naked mole rat, share higher expression of DNA repair genes, including core genes in several DNA repair pathways. A more systematic approach of signaling pathway analysis indicates statistically significant upregulation of several DNA repair signaling pathways in human and naked mole rat compared with mouse. The results of this present work indicate, for the first time, that DNA repair is upregulated in a major metabolic organ in long-lived humans and naked mole rats compared with short-lived mice. These results strongly suggest that DNA repair can be considered a genuine longevity assurance system. PMID:26729707

  7. Interpopulation differences in the salt tolerance of two Cladophora species

    NASA Astrophysics Data System (ADS)

    Thomas, D. N.; Collins, J. C.; Russell, G.

    1990-02-01

    The effects of changes in external salinity upon Baltic and U.K. populations of Cladophora rupestris (L) Kütz and C. glomerata (L) Kütz have been studied. Rates of net photosynthesis after salinity treatment (0-102‰) were used as a measure of salinity tolerance. There were very pronounced differences in the salt tolerance of the two C. glomerata populations, whereas Baltic and U.K. C. rupestris differed significantly only in responses to extreme hyposaline treatment. The effect of salinity on the thallus content of K + and Na + was measured. There were significant differences in the ratios of these ions in populations of both species. The populations also differed significantly in the dimensions of their cells and cellular volume.

  8. Plant response to aqueous effluents derived from in-situ fossil-fuel processing. Part III. Three grass species and their response to Omega 9 and to five produced retort waters: oil shale, tar sands and underground coal gasification. [Basin wildrye; western wheatgrass; alkali sacaton

    SciTech Connect

    Skinner, Q.D.

    1981-12-01

    In situ produced waters collected from retorting oil shale and tar sands to produce oil and in-situ coal gasification to produce gas were tested for their effect on plant growth. Three native grass plant species were utilized for monitoring growth response. Root weight, shoot weight, total dry weight, leaf area, root/shoot ratio and shoot/leaf area ratio were parameters measured. All experiments were conducted under greenhouse conditions using hydroponic techniques and commercial grade perlite as support systems. Measurements were collected after a 10-week growth period. The hypothesis tested was, there is a difference between produced waters diluted by ground water and those where dilution is non-existent and their effect on plant growth. Results indicated that retort water diluted by ground water has a less toxic effect on plant species tested.

  9. [Fatty acids in different edible fish species from Mexico].

    PubMed

    Castro González, María Isabel; Rodríguez, Ana Gabriela Maafs; Galindo Gómez, Carlos

    2013-12-01

    Different biotic and abiotic factors determine the fatty acid (FA) composition of fish tissues and organs. This information is useful for humans due to the fact that fish consumption is associated with health benefits. The aim of the present study was to identify the variation in the concentration of fatty acids, according to different factors, among ten edible marine fish species in Mexico, collected from June to December 2009 in the largest fish market in Mexico City: Euthynnus alletteratus, Sciaenops ocellatus, Bairdiella chrysoura, Sphyraena guachancho, Symphurus elongatus, Istiophorus platypterus, Ophichthus rex, Eugerres plumieri, Eucinostomus entomelas and Oreochromrnis mossambicus. Lipid content was gravimetrically quantified, the fatty acids were determined using a gas chromatograph and the results were statistically analyzed. Total lipid content ranged from 0.93 to 1.95 g/100 g in E. entomelas and O. urolepis hornorum, respectively. E. alletteratus, B. chrysoura, S. elongatus, I. platypterus, O. rex and E. plumieri presented the following order in FA concentration: Polyunsaturated FA (PUFA)>Saturated FA (SFA)>Monounsaturated FA (MUFA). S. ocellatus, S. guachancho and E. entomelas presented SFA>PUFA>MUFA; and only O. mossambicus presented SFA>MUFA>PUFA. O. mossambicus had the highest concentration (mg/100 g) of SFA (559.40) and MUFA (442.60), while B. chrysoura presented the highest content (mg/100 g) of PUFA (663.03), n-3 PUFA (514.03), EPA+DHA (506.10) and n-6 PUFA (145.80). Biotic and abiotic factors of the analyzed fish significantly influenced their FA concentration. Subtropical species presented 42.1% more EPA+DHA than tropical specie. Values presented here will vary according to the changes in the ecosystem and characteristics of each fish species, however the information generated in the present study is useful for improving fish consumption recommendations. PMID:24432548

  10. Variations in Km(CO2) of Ribulose-1,5-bisphosphate Carboxylase among Grasses

    PubMed Central

    Yeoh, Hock-Hin; Badger, Murray R.; Watson, Leslie

    1980-01-01

    A survey of the Km(CO2) values of ribulose-1,5-bisphosphate carboxylase from 60 grass species shows that enzyme from C3 grasses consistently exhibits lower Km(CO2) than does that from C4 grasses. Systematically ordered variation in Km(CO2) of ribulose-1,5-bisphosphate carboxylases from C3 and C4 grasses is also apparent and, among C4 grasses, this shows some correlation with C4 types. PMID:16661586

  11. The effect of enzyme addition on anaerobic digestion of JoseTall Wheat Grass.

    PubMed

    Romano, Rowena T; Zhang, Ruihong; Teter, Sarah; McGarvey, Jeffery A

    2009-10-01

    The effects of the addition of enzyme products containing cellulase, hemicellulase, and beta-glucosidase to anaerobic digestion systems were studied using JoseTall Wheat Grass (wheat grass) as a model substrate. Anaerobic digestion tests were performed using batch reactors operated at 50 degrees C. The application of enzyme products in three digestion configurations were simulated and investigated: (1) enzyme addition to a single-stage digester, (2) pre-treatment of wheat grass with enzymes followed by a single-stage anaerobic digestion, and (3) enzyme addition to the first stage (hydrolysis and acidification) of a two-stage digestion system. The enzyme products showed positive effects on the solubilization of wheat grass when used alone to treat the wheat grass. However, no significant differences in biogas and methane yields, and volatile solids reduction resulted when the enzyme products were tested in the anaerobic digestion systems. This reveals that the microorganisms present in the inoculum were effective in carrying out the digestion of wheat grass. The types of microorganisms present in the inoculum were identified using 16S rRNA sequence analysis. A comparison of the sequences between the different inocula revealed that the prevalent operational taxonomic units were similar, but that the acidified inoculum contained a higher percentage of the species Thermotogae. PMID:19467589

  12. Intra-annual rainfall regime shifts competitive interactions between coastal sage scrub and invasive grasses.

    PubMed

    Goldstein, Leah J; Suding, Katharine N

    2014-02-01

    Changes in rainfall distribution, generally predicted by many climate models, can affect resource dynamics and ecosystem function. While little studied, intra-annual rainfall distribution may have particularly strong effects on competitive interactions. Here, we test whether increased rainfall event size and decreased frequency within a growing season can influence competitive dynamics related to the invasion of exotic annual grasses in California coastal sage scrub (CSS). We hypothesized that larger rainfall events and decreased frequency will increase the competitive ability of native CSS species: a deeper root system will permit greater water use during dry periods between pulses and enhance their resource depletion effect on more shallow-rooted grasses. We planted grass and CSS seedlings in an additive competition design under three rainfall treatments: frequent small events, infrequent large events, and infrequent small events. The first two treatments had the same total rainfall but different frequency, while the second and third treatments had the same frequency but different total rainfall. Rainfall treatment altered the competitive interactions between CSS and grasses. In the first year, the competitive effect of annual grasses on shrub seedlings was strongest under the frequent small rainfall regime where they reduced deep soil moisture and light. In year two, the established shrubs began to exert strong competitive effects on grasses, and these effects were strongest under the infrequent small rainfall regime (low total rain) where they reduced shallow soil moisture and decreased grass stomatal conductance. Results suggest that reductions in both rainfall frequency and total rainfall may be important to competitive interactions, and can alter plant community composition and invasion when species have different rooting depths and different responses to soil moisture. PMID:24669735

  13. Accumulation of mercury in selected plant species grown in soils contaminated with different mercury compounds

    SciTech Connect

    Su, Yi; Han, Fengxiang; Shiyab, Safwan; Chen, Jian; Monts, David L.

    2007-07-01

    The objective of our research is to screen and search for suitable plant species for phyto-remediation of mercury-contaminated soil. Currently our effort is specifically focused on mercury removal from the U.S. Department of Energy (DOE) sites, where mercury contamination is a major concern. In order to cost effectively implement mercury remediation efforts, it is necessary now to obtain an improved understanding of biological means of removing mercury and mercury compounds.. Phyto-remediation is a technology that uses various plants to degrade, extract, contain, or immobilize contaminants from soil and water. In particular, phyto-extraction is the uptake of contaminants by plant roots and translocation within the plants to shoots or leaves. Contaminants are generally removed by harvesting the plants. We have investigated phyto-extraction of mercury from contaminated soil by using some of the known metal-accumulating plants since no natural plant species with mercury hyper-accumulating properties has yet been identified. Different natural plant species have been studied for mercury uptake, accumulation, toxicity and overall mercury removal efficiency. Various mercury compounds, such as HgS, HgCl{sub 2}, and Hg(NO{sub 3}){sub 2}, were used as contaminant sources. Different types of soil were examined and chosen for phyto-remediation experiments. We have applied microscopy and diffuse reflectance spectrometry as well as conventional analytical chemistry to monitor the phyto-remediation processes of mercury uptake, translocation and accumulation, and the physiological impact of mercury contaminants on selected plant species. Our results indicate that certain plant species, such as beard grass (Polypogon monospeliensis), accumulated a very limited amount of mercury in the shoots (<65 mg/kg), even though root mercury accumulation is significant (maximum 2298 mg/kg). Consequently, this plant species may not be suitable for mercury phyto-remediation. Other plant species

  14. The role of wild grasses in the management of lepidopterous stem-borers on maize in the humid tropics of western Africa.

    PubMed

    Ndemah, R; Gounou, S; Schulthess, F

    2002-12-01

    Sites in the humid forest of Cameroon and the derived savanna of Benin were selected to evaluate the effect of planting border rows of wild host plants on lepidopterous stem-borer infestations and on maize yield. Grass species were chosen that in surveys and greenhouse trials were highly attractive to ovipositing female moths but with offspring mortality of close to 100%, thus acting as trap plants. In Cameroon, elephant grass Pennisetum purpureum Moench significantly lowered infestations of Busseola fusca (Fuller), Sesamia calamistis Hampson and Eldana saccharina Walker and increased yields of maize though the differences were not significant during all three cropping seasons. In 1998 in Benin, the only grass tested, Pennisetum polystachion L., significantly increased parasitism of mainly S. calamistis eggs by Telenomus spp. and larvae by Cotesia sesamiae Cameron and reduced numbers of the cob-borer Mussidia nigrivenella Ragonot. In 1999, three grass species; P. polystachion, Sorghum arundinaceum (Desv.) Stapf and Panicum maximum Jacq. were tested. Panicum maximum was the most efficient species for suppressing S. calamistis and M. nigrivenella infestations and enhancing egg and larval parasitism. In the Benin trials, with the exception of M. nigrivenella damage to cobs, the grass species tested had no beneficial effect on yield because pest densities were too low and also rodent damage to maize was enhanced with grasses in the vicinity of the crop. By contrast, stand losses due to Fusarium verticillioides Sacc. (Nirenberg), were significantly reduced by border rows of grasses. PMID:17598302

  15. Species differences in biliary excretion of benzo(a)pyrene

    SciTech Connect

    Weyand, E.H.; Bevan, D.R.

    1986-05-01

    Biliary excretion of benzo(a)pyrene (B(a)P) was investigated in rats, hamsters, and guinea pigs following intratracheal administration. (/sup 3/H)-B(a)P, in amounts of approximately 150 ng or 350 ..mu..g, was instilled into lungs and amounts of radioactivity excreted in bile were monitored for six hrs following administration. Differences in biliary excretion of (/sup 3/H)-B(a)P and/or metabolites among species were observed at low doses but not at high doses. Six hours after instillation of a low dose of B(a)P, 70, 54, and 62% of the dose was excreted in bile of rats, hamsters, and guinea pigs, respectively. Upon administration of the higher dose of B(a)P, approximately 50% of the dose was excreted in bile in six hrs by all species. Thus, rats and guinea pigs exhibit differences in biliary excretion of low and high doses of B(a)P whereas hamsters do not. Profiles of phase II metabolites in rats and hamsters were similar at both low and high doses, with the majority of metabolites being glucuronides and thioether conjugates. However, differences in relative amounts of these conjugates were observed between the two doses, with a shift towards a greater proportion of glucuronides at the higher dose. Metabolites in bile from guinea pigs were primarily thioether conjugates, which accounted for 88% of metabolites at the low dose and 95% at the high dose.

  16. Protocols for Robust Herbicide Resistance Testing in Different Weed Species.

    PubMed

    Panozzo, Silvia; Scarabel, Laura; Collavo, Alberto; Sattin, Maurizio

    2015-01-01

    Robust protocols to test putative herbicide resistant weed populations at whole plant level are essential to confirm the resistance status. The presented protocols, based on whole-plant bioassays performed in a greenhouse, can be readily adapted to a wide range of weed species and herbicides through appropriate variants. Seed samples from plants that survived a field herbicide treatment are collected and stored dry at low temperature until used. Germination methods differ according to weed species and seed dormancy type. Seedlings at similar growth stage are transplanted and maintained in the greenhouse under appropriate conditions until plants have reached the right growth stage for herbicide treatment. Accuracy is required to prepare the herbicide solution to avoid unverifiable mistakes. Other critical steps such as the application volume and spray speed are also evaluated. The advantages of this protocol, compared to others based on whole plant bioassays using one herbicide dose, are related to the higher reliability and the possibility of inferring the resistance level. Quicker and less expensive in vivo or in vitro diagnostic screening tests have been proposed (Petri dish bioassays, spectrophotometric tests), but they provide only qualitative information and their widespread use is hindered by the laborious set-up that some species may require. For routine resistance testing, the proposed whole plant bioassay can be applied at only one herbicide dose, so reducing the costs. PMID:26167668

  17. Differences in the volatile compositions of ginseng species (Panax sp.).

    PubMed

    Cho, In Hee; Lee, Hyun Jeong; Kim, Young-Suk

    2012-08-01

    The volatile compositions in dried white ginseng according to species (Panax ginseng, Panax notoginseng, and Panax quinquefolius) were analyzed and compared by applying multivariate statistical techniques to gas chromatography-mass spectrometry data sets. Main volatile compounds of ginseng species in the present study were sesquiterpenes, such as bicyclogermacrene, (E)-β-farnesene, β-panasinsene, calarene, α-humulene, β-elemene, etc. In particular, α-selinene, α-terpinolene, β-bisabolene, β-phellandrene, β-sesquiphellandrene, zingiberene, germacrene D, limonene, α-gurjunene, (E)-caryophyllene, δ-cadinene, (E)-β-farnesene, α-humulene, bicyclogermacrene, longiborn-8-ene, β-neoclovene, and (+)-spathulenol were mainly associated with the difference between P. ginseng and P. notoginseng versus P. quinquefolius species. On the other hand, the discrimination between P. ginseng and P. notoginseng could be constructed by hexanal, 2-pyrrolidinone, (E)-2-heptenal, (E)-2-octenal, heptanal, isospathulenol, (E,E)-2,4-decadienal, 3-octen-2-one, benzaldehyde, 2-pentylfuran, and (E)-2-nonenal. PMID:22804575

  18. Metabolomic Analyses of Leishmania Reveal Multiple Species Differences and Large Differences in Amino Acid Metabolism

    PubMed Central

    Wang, Lijie; Zhang, Tong; Watson, David G.; Silva, Ana Marta; Coombs, Graham H.

    2015-01-01

    Comparative genomic analyses of Leishmania species have revealed relatively minor heterogeneity amongst recognised housekeeping genes and yet the species cause distinct infections and pathogenesis in their mammalian hosts. To gain greater information on the biochemical variation between species, and insights into possible metabolic mechanisms underpinning visceral and cutaneous leishmaniasis, we have undertaken in this study a comparative analysis of the metabolomes of promastigotes of L. donovani, L. major and L. mexicana. The analysis revealed 64 metabolites with confirmed identity differing 3-fold or more between the cell extracts of species, with 161 putatively identified metabolites differing similarly. Analysis of the media from cultures revealed an at least 3-fold difference in use or excretion of 43 metabolites of confirmed identity and 87 putatively identified metabolites that differed to a similar extent. Strikingly large differences were detected in their extent of amino acid use and metabolism, especially for tryptophan, aspartate, arginine and proline. Major pathways of tryptophan and arginine catabolism were shown to be to indole-3-lactate and arginic acid, respectively, which were excreted. The data presented provide clear evidence on the value of global metabolomic analyses in detecting species-specific metabolic features, thus application of this technology should be a major contributor to gaining greater understanding of how pathogens are adapted to infecting their hosts. PMID:26368322

  19. Iodine Emissions from Seaweeds: Species-dependent and Seasonal Differences

    NASA Astrophysics Data System (ADS)

    Adams, Thomas; Ball, Stephen; Leblanc, Catherine; Potin, Philippe

    2015-04-01

    Emissions of iodine from macroalgae into the marine boundary layer (MBL) significantly impact tropospheric chemistry and the biogeochemical cycling of iodine. Gas-phase iodine chemistry perturbs the usual HOx and NOx radical cycles, provides additional sink reactions for tropospheric ozone, and modifies atmospheric oxidizing capacity. Iodine oxides (IxOywith x ≥ 2) formed through the reaction of iodine atoms with ozone nucleate new aerosol particles which, if they grow sufficiently, can act as cloud condensation nuclei (CCN) and so influence the local climate in coastal regions. Some seaweeds, such as brown algae, are important bio-accumulators of iodine. They specifically induce iodine metabolism to protect themselves against oxidative stress, both as a defence mechanism and when exposed to air around low tide. Indeed the dominant emission source of iodine into the atmosphere in coastal regions comes from intertidal macroalgal beds, particularly those of kelp species. We present results from an extensive laboratory study of molecular iodine (I2) emissions from five seaweed species (two Fucales, Ascophyllum nodosum and Fucus vesiculosus, and three kelp species, Laminaria digitata, L. hyperborea and Saccharina latissima). Eighty-four incubation experiments were performed at the Station Biologique in Roscoff (Brittany, France) between September 2012 and June 2013 to quantify species-dependent I2 emission rates in response to progressive air exposure, mimicking low tide, and to investigate any seasonal differences. Measurements were conducted on 'fresh' biological samples: Ascophyllum and Fucus thalli were collected whilst still submerged on an ebbing tide, transported in seawater to the laboratory and analysed immediately; kelp samples were collected by boat, stored in an outside aquarium in running seawater and analysed within a few days. I2 emissions were quantified at high time resolution by broadband cavity enhanced absorption spectrometry (1σ detection limit

  20. Cotrapping different species in ion traps using multiple radio frequencies

    NASA Astrophysics Data System (ADS)

    Trypogeorgos, Dimitris; Foot, Christopher J.

    2016-08-01

    We consider the stability of systems subjected to periodic parametric driving in the context of ions confined by oscillating electric fields. The behavior of these systems can be understood in terms of a pseudopotential approximation and resonances arising from parametric excitation. We investigate the key properties of a way of operating a linear Paul trap with two radio frequencies that simultaneously confines two species with extremely different charge-to-mass ratios. The theoretical calculations have been verified by molecular dynamics simulations and normal modes analysis.

  1. Leaf damage in cool-season grasses subjected to simulated hoof pressures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although a potential for damage to tissue of grasses by grazing animals may exist, there are few reported estimates of susceptibility of different species or cultivars to trampling, and there is no standard method of measurement of damage to tissues of herbage. Experiments were undertaken with excis...

  2. Breeding bird community colonization of sown stands of native grasses in North Dakota

    USGS Publications Warehouse

    Higgins, K.F.; Arnold, T.W.; Barta, R.M.

    1984-01-01

    Breeding passerine birds were studied in three native grass plantings of predominantly western wheatgrass (Agropyron smithii) and green needlegrass (Stipa viridula) in south-central North Dakota during 1982-1984. A total of eight different species of passerines readily colonized this relatively new type of wildlife habitat during the second, third. and fourth growing seasons.

  3. Differentiation of plant age in grasses using remote sensing

    NASA Astrophysics Data System (ADS)

    Knox, Nichola M.; Skidmore, Andrew K.; van der Werff, Harald M. A.; Groen, Thomas A.; de Boer, Willem F.; Prins, Herbert H. T.; Kohi, Edward; Peel, Mike

    2013-10-01

    Phenological or plant age classification across a landscape allows for examination of micro-topographical effects on plant growth, improvement in the accuracy of species discrimination, and will improve our understanding of the spatial variation in plant growth. In this paper six vegetation indices used in phenological studies (including the newly proposed PhIX index) were analysed for their ability to statistically differentiate grasses of different ages in the sequence of their development. Spectra of grasses of different ages were collected from a greenhouse study. These were used to determine if NDVI, NDWI, CAI, EVI, EVI2 and the newly proposed PhIX index could sequentially discriminate grasses of different ages, and subsequently classify grasses into their respective age category. The PhIX index was defined as: (AVNIRn+log(ASWIR2n))/(AVNIRn-log(ASWIR2n)), where AVNIRn and ASWIR2n are the respective normalised areas under the continuum removed reflectance curve within the VNIR (500-800 nm) and SWIR2 (2000-2210 nm) regions. The PhIX index was found to produce the highest phenological classification accuracy (Overall Accuracy: 79%, and Kappa Accuracy: 75%) and similar to the NDVI, EVI and EVI2 indices it statistically sequentially separates out the developmental age classes. Discrimination between seedling and dormant age classes and the adult and flowering classes was problematic for most of the tested indices. Combining information from the visible near infrared (VNIR) and shortwave infrared region (SWIR) region into a single phenological index captures the phenological changes associated with plant pigments and the ligno-cellulose absorption feature, providing a robust method to discriminate the age classes of grasses. This work provides a valuable contribution into mapping spatial variation and monitoring plant growth across savanna and grassland ecosystems.

  4. Effects of the Epichloë fungal endophyte symbiosis with Schedonorus pratensis on host grass invasiveness.

    PubMed

    Shukla, Kruti; Hager, Heather A; Yurkonis, Kathryn A; Newman, Jonathan A

    2015-07-01

    Initial studies of grass-endophyte mutualisms using Schedonorus arundinaceus cultivar Kentucky-31 infected with the vertically transmitted endophyte Epichloë coenophiala found strong, positive endophyte effects on host-grass invasion success. However, more recent work using different cultivars of S. arundinaceus has cast doubt on the ubiquity of this effect, at least as it pertains to S. arundinaceus-E. coenophiala. We investigated the generality of previous work on vertically transmitted Epichloë-associated grass invasiveness by studying a pair of very closely related species: S. pratensis and E. uncinata. Seven cultivars of S. pratensis and two cultivars of S. arundinaceus that were developed with high- or low-endophyte infection rate were broadcast seeded into 2 × 2-m plots in a tilled, old-field grassland community in a completely randomized block design. Schedonorus abundance, endophyte infection rate, and co-occurring vegetation were sampled 3, 4, 5, and 6 years after establishment, and the aboveground invertebrate community was sampled in S. pratensis plots 3 and 4 years after establishment. Endophyte infection did not enable the host grass to achieve high abundance in the plant community. Contrary to expectations, high-endophyte S. pratensis increased plant richness relative to low-endophyte cultivars. However, as expected, high-endophyte S. pratensis marginally decreased invertebrate taxon richness. Endophyte effects on vegetation and invertebrate community composition were inconsistent among cultivars and were weaker than temporal effects. The effect of the grass-Epichloë symbiosis on diversity is not generalizable, but rather specific to species, cultivar, infection, and potentially site. Examining grass-endophyte systems using multiple cultivars and species replicated among sites will be important to determine the range of conditions in which endophyte associations benefit host grass performance and have subsequent effects on co

  5. An outbreak of lethal adenovirus infection among different otariid species.

    PubMed

    Inoshima, Yasuo; Murakami, Tomoaki; Ishiguro, Naotaka; Hasegawa, Kazuhiro; Kasamatsu, Masahiko

    2013-08-30

    An outbreak of fatal fulminant hepatitis at a Japanese aquarium involved 3 otariids: a California sea lion (Zalophus californianus), a South African fur seal (Arctocephalus pusillus) and a South American sea lion (Otaria flavescens). In a span of about a week in February 2012, 3 otariids showed diarrhea and were acutely low-spirited; subsequently, all three animals died within a period of 3 days. Markedly increased aspartate amino transferase and alanine amino transferase activities were observed. Necrotic hepatitis and eosinophilic intranuclear inclusion bodies in liver hepatocytes and intestinal epithelial cells were observed in the South American sea lion on histological examination. Otarine adenovirus DNA was detected from the livers of all three animals by polymerase chain reaction and determination of the sequences showed that all were identical. These results suggest that a single otarine adenovirus strain may have been the etiological agent of this outbreak of fatal fulminant hepatitis among the different otariid species, and it may be a lethal threat to wild and captive otariids. This is the first evidence of an outbreak of lethal adenovirus infection among different otariid species. PMID:23643878

  6. A grass molecular identification system for forensic botany: a critical evaluation of the strengths and limitations.

    PubMed

    Ward, Jodie; Gilmore, Simon R; Robertson, James; Peakall, Rod

    2009-11-01

    Plant material is frequently encountered in criminal investigations but often overlooked as potential evidence. We designed a DNA-based molecular identification system for 100 Australian grasses that consisted of a series of polymerase chain reaction assays that enabled the progressive identification of grasses to different taxonomic levels. The identification system was based on DNA sequence variation at four chloroplast and two mitochondrial loci. Seventeen informative indels and 68 single-nucleotide polymorphisms were utilized as molecular markers for subfamily to species-level identification. To identify an unknown sample to subfamily level required a minimum of four markers or nine markers for species identification. The accuracy of the system was confirmed by blind tests. We have demonstrated "proof of concept" of a molecular identification system for trace botanical samples. Our evaluation suggests that the adoption of a system that combines this approach with DNA sequencing could assist the morphological identification of grasses found as forensic evidence. PMID:19818109

  7. Species differences in the formation of vabicaserin carbamoyl glucuronide.

    PubMed

    Tong, Zeen; Chandrasekaran, Appavu; DeMaio, William; Jordan, Ronald; Li, Hongshan; Moore, Robin; Poola, Nagaraju; Burghart, Peter; Hultin, Theresa; Scatina, JoAnn

    2010-04-01

    Vabicaserin is a potent 5-hydroxtryptamine 2C full agonist with therapeutic potential for a wide array of psychiatric disorders. Metabolite profiles indicated that vabicaserin was extensively metabolized via carbamoyl glucuronidation after oral administration in humans. In the present study, the differences in the extent of vabicaserin carbamoyl glucuronide (CG) formation in humans and in animals used for safety assessment were investigated. After oral dosing, the systemic exposure ratios of CG to vabicaserin were approximately 12 and up to 29 in monkeys and humans, respectively, and the ratios of CG to vabicaserin were approximately 1.5 and 1.7 in mice and dogs, respectively. These differences in systemic levels of CG are likely related to species differences in the rate and extent of CG formation and elimination. Whereas CG was the predominant circulating metabolite in humans and a major metabolite in mice, dogs, and monkeys, it was a relatively minor metabolite in rats, in which oxidative metabolism was the major metabolic pathway. Although the CG was not detected in plasma or urine of rats, approximately 5% of the dose was excreted in bile as CG in the 24-h collection postdose, indicating the rat had the metabolic capability of producing the CG. In vitro, in a CO(2)-enriched environment, the CG was the predominant metabolite in dog and human liver microsomes, a major metabolite in monkey and mice, and only a very minor metabolite in rats. Carbamoyl glucuronidation and hydroxylation had similar contributions to vabicaserin metabolism in mouse and monkey liver microsomes. However, only trace amounts of CG were formed in rat liver microsomes, and other metabolites were more prominent than the CG. In conclusion, significant differences in the extent of formation of the CG were observed among the various species examined. The exposure ratios of CG to vabicaserin were highest in humans, followed by monkeys, then mice and dogs, and lowest in rats, and the in vitro

  8. Phytochemical changes in leaves of subtropical grasses and fynbos shrubs at elevated atmospheric CO 2 concentrations

    NASA Astrophysics Data System (ADS)

    Hattas, D.; Stock, W. D.; Mabusela, W. T.; Green, I. R.

    2005-07-01

    The effects of elevated atmospheric CO 2 concentrations on plant polyphenolic, tannin, nitrogen, phosphorus and total nonstructural carbohydrate concentrations were investigated in leaves of subtropical grass and fynbos shrub species. The hypothesis tested was that carbon-based secondary compounds would increase when carbon gain is in excess of growth requirements. This premise was tested in two ecosystems involving plants with different photosynthetic mechanisms and growth strategies. The first ecosystem comprised grasses from a C 4-dominated, subtropical grassland, where three plots were subjected to three different free air CO 2 enrichment treatments, i.e., elevated (600 to 800 μmol mol -1), intermediate (400 μmol mol -1) and ambient atmospheric CO 2. One of the seven grass species, Alloteropsis semialata, had a C 3 photosynthetic pathway while the other grasses were all C 4. The second ecosystem was simulated in a microcosm experiment where three fynbos species were grown in open-top chambers at ambient and 700 μmol mol -1 atmospheric CO 2 in low nutrient acid sands typical of south western coastal and mountain fynbos ecosystems. Results showed that polyphenolics and tannins did not increase in the grass species under elevated CO 2 and only in Leucadendron laureolum among the fynbos species. Similarly, foliar nitrogen content of grasses was largely unaffected by elevated CO 2, and among the fynbos species, only L. laureolum and Leucadendron xanthoconus showed changes in foliar nitrogen content under elevated CO 2, but these were of different magnitude. The overall decrease in nitrogen and phosphorus and consequent increase in C:N and C:P ratio in both ecosystems, along with the increase in polyphenolics and tannins in L. laureolum in the fynbos ecosystem, may negatively affect forage quality and decomposition rates. It is concluded that fast growing grasses do not experience sink limitation and invest extra carbon into growth rather than polyphenolics and

  9. Physiological and Morphological Responses of Ischaemum rugosum Salisb. (Wrinkled Grass) to Different Nitrogen Rates and Rice Seeding Rates

    PubMed Central

    Awan, Tahir Hussain; Chauhan, Bhagirath Singh; Cruz, Pompe C. Sta.

    2014-01-01

    Ischaemum rugosum is a competitive weed in direct-seeded rice systems. Developing integrated weed management strategies that promote the suppression of weeds by crop density, cultivar selection, and nutrition requires better understanding of the extent to which rice interferes with the growth of this weed and how it responds to resource limitation due to rice interference. The growth of I. rugosum was studied when grown with four rice seeding rates (0, 25, 50, and 100 kg ha−1) and four nitrogen (N) rates (0, 50, 100, and 150 kg ha−1). Compared to the weed plants grown alone, weed tiller number was reduced by 63–80%, leaf number by 68–77%, leaf area by 69–77%, leaf biomass by 72–84%, and inflorescence biomass by 81–93% at the rice seeding rates of 25–100 kg ha−1. All these parameters increased with increasing rates of N from 0 to 150 kg ha−1. At weed maturity, I. rugosum plants were 100% taller than rice at 0 kg N ha−1, whereas, with added N, the weeds were only 50% taller than rice. Weed biomass increased by 82–160%, whereas rice biomass increased by 92–229%, with the application of 50–150 kg N ha−1. Added N favored rice biomass production more than it did the weed. Rice interference reduced the height and biomass of I. rugosum, but did not suppress its growth completely. I. rugosum showed the ability to reduce the effects of rice interference by increasing leaf area, leaf weight ratio, and specific leaf area, and by decreasing the root-shoot weight ratio in comparison to the weed plants grown alone. The results suggest that rice crop interference alone may reduce I. rugosum growth but may not provide complete control of this weed. The need for integrated weed management practices to effectively control this weed species is highlighted. PMID:24910995

  10. Physiological and morphological responses of Ischaemum rugosum Salisb. (wrinkled grass) to different nitrogen rates and rice seeding rates.

    PubMed

    Awan, Tahir Hussain; Chauhan, Bhagirath Singh; Cruz, Pompe C Sta

    2014-01-01

    Ischaemum rugosum is a competitive weed in direct-seeded rice systems. Developing integrated weed management strategies that promote the suppression of weeds by crop density, cultivar selection, and nutrition requires better understanding of the extent to which rice interferes with the growth of this weed and how it responds to resource limitation due to rice interference. The growth of I. rugosum was studied when grown with four rice seeding rates (0, 25, 50, and 100 kg ha(-1)) and four nitrogen (N) rates (0, 50, 100, and 150 kg ha(-1)). Compared to the weed plants grown alone, weed tiller number was reduced by 63-80%, leaf number by 68-77%, leaf area by 69-77%, leaf biomass by 72-84%, and inflorescence biomass by 81-93% at the rice seeding rates of 25-100 kg ha(-1). All these parameters increased with increasing rates of N from 0 to 150 kg ha(-1). At weed maturity, I. rugosum plants were 100% taller than rice at 0 kg N ha(-1), whereas, with added N, the weeds were only 50% taller than rice. Weed biomass increased by 82-160%, whereas rice biomass increased by 92-229%, with the application of 50-150 kg N ha(-1). Added N favored rice biomass production more than it did the weed. Rice interference reduced the height and biomass of I. rugosum, but did not suppress its growth completely. I. rugosum showed the ability to reduce the effects of rice interference by increasing leaf area, leaf weight ratio, and specific leaf area, and by decreasing the root-shoot weight ratio in comparison to the weed plants grown alone. The results suggest that rice crop interference alone may reduce I. rugosum growth but may not provide complete control of this weed. The need for integrated weed management practices to effectively control this weed species is highlighted. PMID:24910995

  11. DIFFERENCES IN RELEASE AND TRANSPORT OF MANURE-BORNE E. COLI AND ENTEROCOCCI IN GRASS BUFFER CONDITIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Echerichia coli and Enterococci are common indicator organisms used to detect potential fecal contamination of surface and ground water and to determine water quality. Coupled monitoring of both organisms in karst demonstrated differences in dynamics of their concentrations in waters that were reach...

  12. The potential of C4 grasses for cellulosic biofuel production.

    PubMed

    van der Weijde, Tim; Alvim Kamei, Claire L; Torres, Andres F; Vermerris, Wilfred; Dolstra, Oene; Visser, Richard G F; Trindade, Luisa M

    2013-01-01

    With the advent of biorefinery technologies enabling plant biomass to be processed into biofuel, many researchers set out to study and improve candidate biomass crops. Many of these candidates are C4 grasses, characterized by a high productivity and resource use efficiency. In this review the potential of five C4 grasses as lignocellulosic feedstock for biofuel production is discussed. These include three important field crops-maize, sugarcane and sorghum-and two undomesticated perennial energy grasses-miscanthus and switchgrass. Although all these grasses are high yielding, they produce different products. While miscanthus and switchgrass are exploited exclusively for lignocellulosic biomass, maize, sorghum, and sugarcane are dual-purpose crops. It is unlikely that all the prerequisites for the sustainable and economic production of biomass for a global cellulosic biofuel industry will be fulfilled by a single crop. High and stable yields of lignocellulose are required in diverse environments worldwide, to sustain a year-round production of biofuel. A high resource use efficiency is indispensable to allow cultivation with minimal inputs of nutrients and water and the exploitation of marginal soils for biomass production. Finally, the lignocellulose composition of the feedstock should be optimized to allow its efficient conversion into biofuel and other by-products. Breeding for these objectives should encompass diverse crops, to meet the demands of local biorefineries and provide adaptability to different environments. Collectively, these C4 grasses are likely to play a central role in the supply of lignocellulose for the cellulosic ethanol industry. Moreover, as these species are evolutionary closely related, advances in each of these crops will expedite improvements in the other crops. This review aims to provide an overview of their potential, prospects and research needs as lignocellulose feedstocks for the commercial production of biofuel. PMID:23653628

  13. Mineral concentration in selected native temperate grasses with potential use as biofuel feedstock.

    PubMed

    El-Nashaar, H M; Griffith, S M; Steiner, J J; Banowetz, G M

    2009-07-01

    Stands of native grasses along roadways, in buffer strips, riparian zones and grass prairies have potential utility as feedstock for bioenergy production. The sustainability of harvesting these stands is reliant, in part, on knowledge of the mineral concentration of the harvested grasses because removal of mineral nutrients such as phosphorus (P) and potassium (K) can impact subsequent biomass production and ecosystem services associated with these stands. Mineral content of biomass, particularly that of silicon (Si), chlorine (Cl), and sulfur (S) also impacts thermochemical conversion approaches that convert grasses into bioproducts. This study quantified Cl, S, Si, P and K in Bromus marginatus, Elymus glaucus, Poa secunda, Pseudoroegneria, Elymus lanceolatus, Elymus trachycaulus, Leymus cinereus, Leymus triticoides, and Pseudoroegneria spicata collected at three growth developmental stages from four plant introduction stations located in the western US. Differences (P< or =0.05) in mineral concentrations were associated with developmental stage, species, and location. Variability was greatest in Si concentrations which ranged from 1847 to 28620 mg kg(-1), similar to those recorded in other grasses. Variability in Cl and S concentrations also occurred, but at less magnitude than that of Si. Concentrations of P and K, two mineral fertilizer components, varied approximately threefold among these grasses. Differences in mineral concentrations among these grasses were not completely dependent upon soil mineral content. Long-term evaluations of available soil mineral concentrations under contrasting management practices are needed to quantify how local conditions impact mineral cycling, and in turn, the sustainability of harvesting these stands. The data presented here establish baselines for these species in locations subject to contrasting environmental and microbiological conditions that affect mineral cycling and availability. PMID:19329307

  14. Possible species differences between Sarcocystis from mule deer and cattle.

    PubMed

    Hudkins-Vivion, G; Kistner, T P; Fayer, R

    1976-01-01

    In preliminary studies with Sarcocystis from bovine (Bos taurus) and mule deer (Odocoileus hemionus hemionus), a coccidia-free laboratory dog (Canis familiaris) and captive coyote (Canis latrans) were fed flesh from a local Sarcocystis-infected bovine and later flesh from an infected mule deer from Eastern Oregon. Sporocysts were passed in the feces of both canine hosts 10-15 days after ingestion of infected meat. There was a statistical difference in the size of sporocysts derived from bovine and deer. It was concluded that the Sarcocystis from bovine and mule deer probably constitute distinct species with a life cycle dependent on the respective ruminant host and a canine host. PMID:815572

  15. Distinct antibody species: structural differences creating therapeutic opportunities.

    PubMed

    Muyldermans, Serge; Smider, Vaughn V

    2016-06-01

    Antibodies have been a remarkably successful class of molecules for binding a large number of antigens in therapeutic, diagnostic, and research applications. Typical antibodies derived from mouse or human sources use the surface formed by complementarity determining regions (CDRs) on the variable regions of the heavy chain/light chain heterodimer, which typically forms a relatively flat binding surface. Alternative species, particularly camelids and bovines, provide a unique paradigm for antigen recognition through novel domains which form the antigen binding paratope. For camelids, heavy chain antibodies bind antigen with only a single heavy chain variable region, in the absence of light chains. In bovines, ultralong CDR-H3 regions form an independently folding minidomain, which protrudes from the surface of the antibody and is diverse in both its sequence and disulfide patterns. The atypical paratopes of camelids and bovines potentially provide the ability to interact with different epitopes, particularly recessed or concave surfaces, compared to traditional antibodies. PMID:26922135

  16. Gastrointestinal somatostatin: extraction and radioimmunoassay in different species.

    PubMed Central

    McIntosh, C; Arnold, R; Bothe, E; Becker, H; Köbberling, J; Creutzfeldt, W

    1978-01-01

    A radioimmunoassay capable of detecting 300 fg somatostatin has been developed and levels of the polypeptide in gastrointestinal tissues from man, dog, and rat have been measured. Rapid freezing of collected samples and careful control of extraction is necessary. Concentrations in different regions of dog antrum (425 +/- 50 to 773 +/- 254 ng/g tissue) are similar to those in antrum from duodenal ulcer patients and control subjects: 614 +/- 125 and 465 +/- 104 ng/g tissue respectively. Levels in histologically normal human pancreas (253 +/- 43 ng/g tissue) are comparable with those in dog pancreas (333 +/- 66 ng/g tissue), whereas in two cases of neonatal hypoglycaemia the concentration exceeded 3000 ng/g tissue. On gel chromatography the majority of immunoreactive somatostatin elutes as the synthetic tetradecapeptide and a small fraction as a larger species. PMID:680597

  17. Pests in Ornamental Grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ornamental perennial grasses are becoming increasingly popular in the landscape due to their beauty and ease of care. Although few pest problems are encountered in ornamental grasses, they are not immune to insects and disease. Two lined spittlebugs (Prosapia bicincta) can cause damage to ornament...

  18. [The selection of sexual partners of different species by mammals].

    PubMed

    Sambraus, H H

    1990-06-01

    It appears biologically sensible that every animal seeks its mating partner within its own species. Sexual contact with alien species may occur when animals are isolated from members of their own species, particularly, however, after they have been raised in the environment of alien species. Copulations of this nature do not, as a rule, result in offspring, although an entire series of bastards among closely related species is known. Among domestic animals bastardization is partly planned systematically as this has advantages in comparison to original forms. Sodomy, i.e. interspecific sexual contact between a human being and an animal, was already described in ancient times. PMID:2383225

  19. Chemical behavior of different species of phosphorus in coagulation.

    PubMed

    Park, Taejun; Ampunan, Vanvimol; Lee, Sanghyup; Chung, Eunhyea

    2016-02-01

    Phosphorus is one of the elements that have a significant impact on such environmental problems as eutrophication or algal bloom. Phosphorus compounds in water can be hydrolyzed to orthophosphate that is the only form of phosphorus that algae can assimilate. In this study, phosphorus removal in terms of orthophosphate and total phosphorus from wastewater was studied using alum or ferric ions as coagulants. It was observed that alum shows higher phosphorus removal efficiency than ferric ions in the same mole ratio concentrations. The proportion of orthophosphate among total phosphorus did not change significantly during coagulation process when the coagulant concentration is low. However, the proportion becomes gradually decreased as the coagulant concentration increases. Not only the electrolyte concentration difference in solution, but the characteristics of orthophosphate and polyphosphate such as reactivity and ionic size might also cause the differences in the removal rate. Orthophosphate that has greater reactivity than other phosphorus species would be involved in chemical reactions dominantly when large amounts of coagulants are applied. However, the effect of reactivity was diminished due to the large ionic size of polyphosphate and low concentration of electrolyte in low coagulant concentration during the coagulation process. PMID:26598995

  20. Convergent tapering of xylem conduits in different woody species.

    PubMed

    Anfodillo, Tommaso; Carraro, Vinicio; Carrer, Marco; Fior, Claudio; Rossi, Sergio

    2006-01-01

    A recent theoretical model (the West, Brown and Enquist, WBE model) hypothesized that plants have evolved a network of xylem conduits with a tapered structure (narrower conduits distally) which should minimize the cost of water transport from roots to leaves. Specific measurements are required to test the model predictions. We sampled both angiosperms and gymnosperms (50 trees) growing in different environments with heights ranging from 0.5 to 44.4 m, measuring variations of the xylem-conduit diameter from tree top to stem base. In all trees measured, mean hydraulically weighted conduit diameters (Dh) at the tree top were narrower than those at the stem base. In actively growing trees, the longitudinal variation of Dh showed a degree of tapering in agreement with WBE predictions, while trees close to their maximum height showed slightly lower conduit tapering. Comparing different species, a very good correlation was observed between degree of xylem tapering and tree height (r2 = 0.88; P < 0.0001) independently of any other variable (age, site, altitude, etc.). As predicted by WBE, sampled trees seemed to converge towards similar xylem conduit tapering. However, trees approaching their maximum height had a nonoptimal tapering which appeared insufficient to compensate for the progressive increase in tree height. PMID:16411931

  1. How might you compare mitochondria from different tissues and different species?

    PubMed

    Hulbert, A J; Turner, Nigel; Hinde, Jack; Else, Paul; Guderley, Helga

    2006-02-01

    Mitochondria were isolated from the liver, kidney and mixed hindlimb skeletal muscle of three vertebrate species; the laboratory rat Rattus norvegicus, the bearded dragon lizard Pogona vitticeps, and the cane toad Bufo marinus. These vertebrate species are approximately the same body mass and have similar body temperatures. The content of cytochromes B, C, C1, and A were measured in these isolated mitochondria by oxidised-reduced difference spectra. Adenine nucleotide translocase (ANT) was measured by titration of mitochondrial respiration with carboxyactractyloside and the protein and phospholipid content of isolated mitochondria were also measured. Fatty acid composition of mitochondrial phospholipids was measured. Mitochondrial respiration was measured at 37 degrees C under states III and IV conditions as well as during oligomycin inhibition. Species differed in the ratios of different mitochondrial cytochromes. Muscle mitochondria differed from kidney and liver mitochondria by having a higher ANT content relative to cytochrome content. Respiration rates were compared relative to a number of denominators and found to be most variable when expressed relative to mitochondrial protein content and least variable when expressed relative to mitochondrial cytochrome A and ANT content. The turnover of cytochromes was calculated and found to vary between 1 and 94 electrons s(-1). The molecular activity of mitochondrial cytochromes was found to be significantly positively correlated with the relative polyunsaturation of mitochondrial membrane lipids. PMID:16408229

  2. No effect of seed source on multiple aspects of ecosystem functioning during ecological restoration: cultivars compared to local ecotypes of dominant grasses.

    PubMed

    Baer, Sara G; Gibson, David J; Gustafson, Danny J; Benscoter, Allison M; Reed, Lewis K; Campbell, Ryan E; Klopf, Ryan P; Willand, Jason E; Wodika, Ben R

    2014-02-01

    Genetic principles underlie recommendations to use local seed, but a paucity of information exists on the genetic distinction and ecological consequences of using different seed sources in restorations. We established a field experiment to test whether cultivars and local ecotypes of dominant prairie grasses were genetically distinct and differentially influenced ecosystem functioning. Whole plots were assigned to cultivar and local ecotype grass sources. Three subplots within each whole plot were seeded to unique pools of subordinate species. The cultivar of the increasingly dominant grass, Sorghastrum nutans, was genetically different than the local ecotype, but genetic diversity was similar between the two sources. There were no differences in aboveground net primary production, soil carbon accrual, and net nitrogen mineralization rate in soil between the grass sources. Comparable productivity of the grass sources among the species pools for four years shows functional equivalence in terms of biomass production. Subordinate species comprised over half the aboveground productivity, which may have diluted the potential for documented trait differences between the grass sources to influence ecosystem processes. Regionally developed cultivars may be a suitable alternative to local ecotypes for restoration in fragmented landscapes with limited gene flow between natural and restored prairie and negligible recruitment by seed. PMID:24567751

  3. No effect of seed source on multiple aspects of ecosystem functioning during ecological restoration: cultivars compared to local ecotypes of dominant grasses

    PubMed Central

    Baer, Sara G; Gibson, David J; Gustafson, Danny J; Benscoter, Allison M; Reed, Lewis K; Campbell, Ryan E; Klopf, Ryan P; Willand, Jason E; Wodika, Ben R

    2014-01-01

    Genetic principles underlie recommendations to use local seed, but a paucity of information exists on the genetic distinction and ecological consequences of using different seed sources in restorations. We established a field experiment to test whether cultivars and local ecotypes of dominant prairie grasses were genetically distinct and differentially influenced ecosystem functioning. Whole plots were assigned to cultivar and local ecotype grass sources. Three subplots within each whole plot were seeded to unique pools of subordinate species. The cultivar of the increasingly dominant grass, Sorghastrum nutans, was genetically different than the local ecotype, but genetic diversity was similar between the two sources. There were no differences in aboveground net primary production, soil carbon accrual, and net nitrogen mineralization rate in soil between the grass sources. Comparable productivity of the grass sources among the species pools for four years shows functional equivalence in terms of biomass production. Subordinate species comprised over half the aboveground productivity, which may have diluted the potential for documented trait differences between the grass sources to influence ecosystem processes. Regionally developed cultivars may be a suitable alternative to local ecotypes for restoration in fragmented landscapes with limited gene flow between natural and restored prairie and negligible recruitment by seed. PMID:24567751

  4. Distinguishing grass from ground using LiDAR: Techniques and applications

    NASA Astrophysics Data System (ADS)

    Pelletier, J. D.; Swetnam, T.; Papuga, S. A.; Nelson, K.; Brooks, P. D.; Harpold, A. A.; Chorover, J.

    2011-12-01

    Standard protocols exist for extracting bare-earth Digital Elevation Models (DEMs) from LiDAR point clouds that include trees and other large woody vegetation. Grasses and other herbaceous plants can also obscure the ground surface, yet methods for optimally distinguishing grass from ground to generate accurate LiDAR-based raster products for geomorphic and ecological applications are still under development. Developing such methods is important because LiDAR-based difference products (e.g. snow thickness) require accurate representations of the ground surface and because raster data for grass height and density have important applications in ecology. In this study, we developed and tested methods for constructing optimal bare-earth and grass height raster layers from LiDAR point clouds and compared the results to high-quality field-based measurements of grass height, density, and species type for nearly 1000 precisely geo-referenced locations collected during the acquisition of a >200 km^2 airborne LiDAR flight of the Valles Caldera National Preserve (New Mexico). In cases of partially bare ground (where the skewness of return heights above a plane fit to the lowest first returns is sufficiently large), a planar fit to the lowest first returns provides a good method of producing an accurate bare-earth DEM and the statistics of the first returns above that planar fit provide good estimates of the mean and variance of grass height. In areas of relatively thick grass cover, however, a fit to the lowest first returns yields a bare-earth DEM that may be a meter or more above the actual ground surface. Here we propose a method to solve this problem using field-measured correlations among the mean, variance, and skewness of grass heights. In this method, the variance and skewness of the differences between LiDAR first returns and a 10m^2 planar fit to the lowest first returns is used, together with field-based correlations of grass height statistics, to estimate the mean

  5. Molecular control of grass inflorescence development.

    PubMed

    Zhang, Dabing; Yuan, Zheng

    2014-01-01

    The grass family is one of the largest families in angiosperms and has evolved a characteristic inflorescence morphology, with complex branches and specialized spikelets. The origin and development of the highly divergent inflorescence architecture in grasses have recently received much attention. Increasing evidence has revealed that numerous factors, such as transcription factors and plant hormones, play key roles in determining reproductive meristem fate and inflorescence patterning in grasses. Moreover, some molecular switches that have been implicated in specifying inflorescence shapes contribute significantly to grain yields in cereals. Here, we review key genetic and molecular switches recently identified from two model grass species, rice (Oryza sativa) and maize (Zea mays), that regulate inflorescence morphology specification, including meristem identity, meristem size and maintenance, initiation and outgrowth of axillary meristems, and organogenesis. Furthermore, we summarize emerging networks of genes and pathways in grass inflorescence morphogenesis and emphasize their evolutionary divergence in comparison with the model eudicot Arabidopsis thaliana. We also discuss the agricultural application of genes controlling grass inflorescence development. PMID:24471834

  6. Species differences in tumour responses to cancer chemotherapy

    PubMed Central

    Lawrence, Jessica; Cameron, David; Argyle, David

    2015-01-01

    Despite advances in chemotherapy, radiotherapy and targeted drug development, cancer remains a disease of high morbidity and mortality. The treatment of human cancer patients with chemotherapy has become commonplace and accepted over the past 100 years. In recent years, and with a similar incidence of cancer to people, the use of cancer chemotherapy drugs in veterinary patients such as the dog has also become accepted clinical practice. The poor predictability of tumour responses to cancer chemotherapy drugs in rodent models means that the standard drug development pathway is costly, both in terms of money and time, leading to many drugs failing in Phase I and II clinical trials. This has led to the suggestion that naturally occurring cancers in pet dogs may offer an alternative model system to inform rational drug development in human oncology. In this review, we will explore the species variation in tumour responses to conventional chemotherapy and highlight our understanding of the differences in pharmacodynamics, pharmacokinetics and pharmacogenomics between humans and dogs. Finally, we explore the potential hurdles that need to be overcome to gain the greatest value from comparative oncology studies. PMID:26056373

  7. Species difference in adaptive use of public information in sticklebacks.

    PubMed Central

    Coolen, Isabelle; van Bergen, Yfke; Day, Rachel L; Laland, Kevin N

    2003-01-01

    Animals foraging on variable food sources can refine their estimates of patch quality by monitoring the success of others (i.e. collect 'public information'). Here, we show that both three-spined sticklebacks (Gasterosteus aculeatus) and nine-spined sticklebacks (Pungitius pungitius) use past cues provided by others to locate food but only nine-spined sticklebacks use prior public information to assess patch quality, regardless of whether demonstrators were conspecifics or heterospecifics. Moreover, nine-spined but not three-spined sticklebacks preferentially hid in vegetation during the demonstration, a position from which they could observe both patches simultaneously and collect public information. We conclude that species differences in the use of public information can be explained by variations in habitat choice and response to predation. Our findings expand current understanding of the scope of public-information use in animals by showing that fishes can use public-information in a foraging context and from heterospecifics. The study suggests that public-information use is an adaptation that allows animals vulnerable to predation to acquire valuable foraging information at low risk. PMID:14667359

  8. Species differences in metabolism of 1,3-butadiene

    SciTech Connect

    Henderson, R.F.

    1995-02-01

    1,3-Butadiene (BD) is a 4-carbon gaseous compound with two double bonds. Used in high tonnage to make styrene-butadiene polymers in the rubber industry. Because of large amounts in use, BD was tested for toxicity in 2-year inhalation exposures of both Sprague-Dawley rats and B6C3F{sub 1} mice. The results of the two-species studies were dramatically different. In the initial study in mice, BD was shown to be a potent multiple-site carcinogen at exposure levels of 625 and 1250 ppM. There were increased incidences of neoplasia in the heart, lung, mammary gland, and ovary; malignant lymphomas resulted in early deaths of the mice so that the planned 2-year study was stopped after only 61 weeks of exposure. The second study in mice was conducted at much lower exposure concentrations (6.25, 20, 62.5, 200, and 625 ppM) and lasted 104 weeks. Increased incidences of hemangiosarcomas of the heart and lung neoplasia were observed in males exposed to 62.5 ppM BD, while females had increased lung neoplasia even at the 6.25 ppM exposure level. Early deaths from lymphomas were again observed at the high exposure concentration (625 ppm). A noncancer toxicity observed in mice was a macrocytic, megaloblastic anemia.

  9. Species differences in tumour responses to cancer chemotherapy.

    PubMed

    Lawrence, Jessica; Cameron, David; Argyle, David

    2015-07-19

    Despite advances in chemotherapy, radiotherapy and targeted drug development, cancer remains a disease of high morbidity and mortality. The treatment of human cancer patients with chemotherapy has become commonplace and accepted over the past 100 years. In recent years, and with a similar incidence of cancer to people, the use of cancer chemotherapy drugs in veterinary patients such as the dog has also become accepted clinical practice. The poor predictability of tumour responses to cancer chemotherapy drugs in rodent models means that the standard drug development pathway is costly, both in terms of money and time, leading to many drugs failing in Phase I and II clinical trials. This has led to the suggestion that naturally occurring cancers in pet dogs may offer an alternative model system to inform rational drug development in human oncology. In this review, we will explore the species variation in tumour responses to conventional chemotherapy and highlight our understanding of the differences in pharmacodynamics, pharmacokinetics and pharmacogenomics between humans and dogs. Finally, we explore the potential hurdles that need to be overcome to gain the greatest value from comparative oncology studies. PMID:26056373

  10. Dual effects of different selenium species on wheat.

    PubMed

    Guerrero, B; Llugany, M; Palacios, O; Valiente, M

    2014-10-01

    Wheat (Triticum aestivum) and its derivative products account for a major source of dietary intake of selenium (Se) in humans and animals, because of its essentiality due to its presence in vital enzymes. Se antioxidant role has resulted in the popularity of agronomic biofortification practises in Se deficient areas. Controlling Se uptake, metabolism, translocation and accumulation in plants will be important to decrease healthy risk of toxicity and deficiency and to help selecting adequate methods for biofortification. Selenate and selenite are the two main inorganic Se forms available in soil and in most of the studies are given separately. That study reveals that both Se species behave differently but combined the prevalent pattern is that of selenite; so it is taken up faster and it seems that interferes with selenate uptake and transport. Selenium has dual effects on wheat plants; at low concentrations it acts as growth stimulant whereas at high concentrations it reduces root elongation and biomass production and alters uptake and translocation of several essential nutrients. PMID:25208508