Sample records for bromus auleticus trin
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Directory of Open Access Journals (Sweden)
Leonardo Luís Artico
2017-04-01
Full Text Available Chromosome morphometry and nuclear DNA content are useful data for cytotaxonomy and to understand the evolutionary history of different taxa. For the genus Bromus Linnaeus, 1753, distinct ploidy levels have been reported, occurring from diploid to duodecaploid species. The geographic distribution of Bromus species has been correlated with chromosome number and ploidy level. In this study, the aims were to determine the nuclear genome size and characterize the karyotype of the South American Bromus species: Bromus auleticus Trinius ex Nees, 1829, Bromus brachyanthera Döll, 1878 and Bromus catharticus Vahl, 1791. The mean nuclear 2C value ranged from 2C = 12.64 pg for B. catharticus to 2C = 17.92 pg for B. auleticus, meaning a maximum variation of 2C = 5.28 pg, equivalent to 41.70%. Despite this significant difference in 2C value, the three species exhibit the same chromosome number, 2n = 6x = 42, which confirms their hexaploid origin. Corroborating the genome size, the chromosome morphometry (total, short- and long-arm length and, consequently, the class differed among the karyotypes of the species. Based on the first karyograms for these Bromus species, some morphologically similar and several distinct chromosome pairs were found. Therefore, the karyotype characterization confirmed the hexaploid origin of the studied Bromus species, which differ in relation to the karyogram and the nuclear 2C value. Considering this, cytogenetics and flow cytometry can be used to discriminate Bromus species, contributing to taxonomy and systematic studies and providing information on the evolutionary history of this taxa.
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Artico, Leonardo Luís; Mazzocato, Ana Cristina; Ferreira, Juliano Lino; Carvalho, Carlos Roberto; Clarindo, Wellington Ronildo
2017-01-01
Chromosome morphometry and nuclear DNA content are useful data for cytotaxonomy and to understand the evolutionary history of different taxa. For the genus Bromus Linnaeus, 1753, distinct ploidy levels have been reported, occurring from diploid to duodecaploid species. The geographic distribution of Bromus species has been correlated with chromosome number and ploidy level. In this study, the aims were to determine the nuclear genome size and characterize the karyotype of the South American Bromus species: Bromus auleticus Trinius ex Nees, 1829, Bromus brachyanthera Döll, 1878 and Bromus catharticus Vahl, 1791. The mean nuclear 2C value ranged from 2C = 12.64 pg for B. catharticus to 2C = 17.92 pg for B. auleticus , meaning a maximum variation of 2C = 5.28 pg, equivalent to 41.70%. Despite this significant difference in 2C value, the three species exhibit the same chromosome number, 2n = 6x = 42, which confirms their hexaploid origin. Corroborating the genome size, the chromosome morphometry (total, short- and long-arm length) and, consequently, the class differed among the karyotypes of the species. Based on the first karyograms for these Bromus species, some morphologically similar and several distinct chromosome pairs were found. Therefore, the karyotype characterization confirmed the hexaploid origin of the studied Bromus species, which differ in relation to the karyogram and the nuclear 2C value. Considering this, cytogenetics and flow cytometry can be used to discriminate Bromus species, contributing to taxonomy and systematic studies and providing information on the evolutionary history of this taxa.
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TOR-inhibitor insensitive-1 (TRIN1) regulates cotyledons greening in Arabidopsis.
Li, Linxuan; Song, Yun; Wang, Kai; Dong, Pan; Zhang, Xueyan; Li, Fuguang; Li, Zhengguo; Ren, Maozhi
2015-01-01
Target of Rapamycin (TOR) is an eukaryotic protein kinase and evolutionally conserved from the last eukaryotic common ancestor (LECA) to humans. The growing evidences have shown that TOR signaling acts as a central controller of cell growth and development. The downstream effectors of TOR have been well-identified in yeast and animals by using the immunosuppression agent rapamycin. However, less is known about TOR in plants. This is largely due to the fact that plants are insensitive to rapamycin. In this study, AZD8055 (AZD), the novel ATP-competitive inhibitor of TOR, was employed to decipher the downstream effectors of TOR in Arabidopsis. One AZD insensitive mutant, T O R - i nhibitor i n sensitive- 1 (trin1), was screened from 10,000 EMS-induced mutation seeds. The cotyledons of trin1 can turn green when its seeds were germinated on ½ MS medium supplemented with 2 μM AZD, whereas the cotyledons greening of wild-type (WT) can be completely blocked at this concentration. Through genetic mapping, TRIN1 was mapped onto the long arm of chromosome 2, between markers SGCSNP26 and MI277. Positional cloning revealed that TRIN1 was an allele of ABI4, which encoded an ABA-regulated AP2 domain transcription factor. Plants containing P35S::TRIN1 or P35S::TRIN1-GUS were hypersensitive to AZD treatment and displayed the opposite phenotype observed in trin1. Importantly, GUS signaling was significantly enhanced in P35S::TRIN1-GUS transgenic plants in response to AZD treatment, indicating that suppression of TOR resulted in the accumulation of TRIN1. These observations revealed that TOR controlled seed-to-seedling transition by negatively regulating the stability of TRIN1 in Arabidopsis. For the first time, TRIN1, the downstream effector of TOR signaling, was identified through a chemical genetics approach.
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Chambers, Jeanne; Germino, Matthew; Belnap, Jayne; Brown, Cynthia; Schupp, Eugene W.; St. Clair, Samuel B
2016-01-01
The factors that determine plant community resistance to exotic annual Bromus species (Bromushereafter) are diverse and context specific. They are influenced by the environmental characteristics and attributes of the community, the traits of Bromus species, and the direct and indirect interactions of Bromus with the plant community. Environmental factors, in particular ambient and soil temperatures, have significant effects on the ability of Bromus to establish and spread. Seasonality of precipitation relative to temperature influences plant community resistance toBromus through effects on soil water storage, timing of water and nutrient availability, and dominant plant life forms. Differences among plant communities in how well soil resource use by the plant community matches resource supply rates can influence the magnitude of resource fluctuations due to either climate or disturbance and thus the opportunities for invasion. The spatial and temporal patterns of resource availability and acquisition of growth resources by Bromus versus native species strongly influence resistance to invasion. Traits of Bromus that confer a “priority advantage” for resource use in many communities include early-season germination and high growth and reproductive rates. Resistance to Bromus can be overwhelmed by high propagule supply, low innate seed dormancy, and large, if short-lived, seed banks. Biological crusts can inhibit germination and establishment of invasive annual plants, including several annual Bromus species, but are effective only in the absence of disturbance. Herbivores can have negative direct effects on Bromus, but positive indirect effects through decreases in competitors. Management strategies can be improved through increased understanding of community resistance to exotic annual Bromus species.
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Jeanne C. Chambers; Matthew J. Germino; Jayne Belnap; Cynthia S. Brown; Eugene W. Schupp; Samuel B. St. Clair
2016-01-01
The factors that determine plant community resistance to exotic annual Bromus species (Bromus hereafter) are diverse and context specific. They are influenced by the environmental characteristics and attributes of the community, the traits of Bromus species, and the direct and indirect interactions of Bromus with the plant community. Environmental factors, in...
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Nota sobre Bromus Willdenowii Kunth
Directory of Open Access Journals (Sweden)
Pinto Escobar Polidoro
1985-09-01
Full Text Available Procedente de Suramérica fue introducida en Norteamérica una planta que es utilizada como buen forraje y que corresponde a una especie del género Bromus de la sección Ceratochloa (Gramineae referida a Bromus unioloides Kunth. HITCHCOCK (1934 después de examinar fragmentos del ejernplar de Commerson "ex agro bonaerinsi" (C, considerado como tipo nomenclatural y asumir que el ejemplar había sido obtenido en Lima (Perú, 10 asignó a Bromus catbarticus Yah!. Posteriormente PARODI (1956 Y HUBBARD (1956, rechazaron el nornbre de Bromus catbarticus Yah 1 como nomen confussum y propusieron la validez de Bromus unioloides Kunth.
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Notes on Alien Bromus Grasses in Taiwan
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Ming-Jer Jung
2006-06-01
Full Text Available Bromus carinatus Hook. & Arn., Bromus hordeaceus L., Bromus pubescens Muhl. ex Willd. and Bromus secalinus L. were recently found at middle elevations of southern and central Taiwan, respectively. We present taxonomic treatments, distribution map, and line-drawings of these introduced alien brome grasses.
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Introduction: Exotic Annual Bromus in the Western USA
Germino, Matthew; Chambers, Jeanne C.; Brown, Cynthia S.
2016-01-01
The spread and impacts of exotic species are unambiguous, global threats to many ecosystems. A prominent example is the suite of annual grasses in the Bromus genus (Bromus hereafter) that originate from Europe and Eurasia but have invaded or are invading large areas of the Western USA. This book brings a diverse, multidisciplinary group of authors together to synthesize current knowledge, research needs, and management implications for Bromus. Exotic plant invasions are multifaceted problems, and understanding and managing them requires the biological, ecological, sociological, and economic perspectives that are integrated in this book. Knowing how well information from one geographic or environmental setting can transfer to another is a key need for broadly distributed Bromus species especially given ongoing climate change. Thus, the chapters in the book compare and contrast invasibility of different ecoregions and invasiveness of different Bromus species. A universal theme is managing for ecosystems that are resilient to disturbance and resistant to invasion which will be essential for adaptation to the human-caused problem of Bromus in the Western USA.
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Land uses, fire, and invasion: Exotic annual Bromus and human dimensions
Pyke, David A.; Chambers, Jeanne C.; Beck, Jeffrey L.; Brooks, Matthew L.; Mealor, Brian A.
2016-01-01
Human land uses are the primary cause of the introduction and spread of exotic annual Bromusspecies. Initial introductions were likely linked to contaminated seeds used by homesteading farmers in the late 1880s and early 1900s. Transportation routes aided their spread. Unrestricted livestock grazing from the 1800s through the mid-1900s reduced native plant competitors leaving large areas vulnerable to Bromus dominance. Ecosystems with cooler and moister soils tend to have greater potential to recover from disturbances (resilience) and to be more resistant to Bromusinvasion and dominance. Warmer and drier ecosystems are less resistant to Bromus and are threatened by altered fire regimes which can lead to Bromus dominance, impacts to wildlife, and alternative stable states. Native Americans used fire for manipulating plant communities and may have contributed to the early dominance of Bromus in portions of California. Fire as a tool is now limited to site preparation for revegetation in most ecosystems where Bromus is a significant problem. Once Bromus dominates, breaking annual grass/fire cycles requires restoring fire-tolerant perennial grasses and forbs, which can compete with Bromus and resist its dominance. Current weed management policies often lack regulations to prevent further expansion of Bromus. Research is needed on how and where livestock grazing might help increase perennial grass and forb cover and density to create ecosystems that are more resistant to Bromus. Also, studies are needed to ascertain the role, if any, of oil and gas development in contributing to the spread of Bromus.
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Ecosystem impacts of exotic annual invaders in the Genus Bromus
Germino, Matthew J.; Belnap, Jayne; Stark, John M.; Allen, Edith B.; Rau, Benjamin M.
2016-01-01
An understanding of the impacts of exotic plant species on ecosystems is necessary to justify and guide efforts to limit their spread, restore natives, and plan for conservation. Invasive annual grasses such as Bromus tectorum, B. rubens, B. hordeaceus, and B. diandrus (hereafter collectively referred to as Bromus) transform the structure and function of ecosystems they dominate. Experiments that prove cause-and-effect impacts of Bromus are rare, yet inferences can be gleaned from the combination of Bromus-ecosystem associations, ecosystem condition before/after invasion, and an understanding of underlying mechanisms. Bromus typically establishes in bare soil patches and can eventually replace perennials such as woody species or bunchgrasses, creating a homogeneous annual cover. Plant productivity and cover are less stable across seasons and years when Bromus dominates, due to a greater response to annual climate variability. Bromus’ “flash” of growth followed by senescence early in the growing season, combined with shallow rooting and annual habit, may lead to incomplete use of deep soil water, reduced C sequestration, and accelerated nutrient cycling. Litter produced by Bromus alters nearly all aspects of ecosystems and notably increases wildfire occurrence. Where Bromus has become dominant, it can decrease soil stability by rendering soils bare for months following fire or episodic, pathogen-induced stand failure. Bromus-invaded communities have lower species diversity, and associated species tend to be generalists adapted to unstable and variable habitats. Changes in litter, fire, and soil properties appear to feedback to reinforce Bromus’ dominance in a pattern that portends desertification.
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Nota sobre el Ejemplar Tipo de "Bromus catharticus" Vahl
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Pinto Escobar Polidoro
1976-09-01
Full Text Available EI agrostólogo inglés C. E. Hubbard y simultáneamente el agrostólogo argentino Lorenzo Parodi en sendas notas (1956 concluyeron en declarar dudosa la especie Bromus catharticus Vahl y restablecer para la planta conocida como "rescue grass" en USA y "cebadilla criolla" en la Argentina el nombre Bromus unioloides H. B. K. Este trabajo presenta nuevas evidencias que permiten restablecer la validez de Bromus catharticus Vahl.
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Shkalim, Eleanor; Ben-Porath, Yossef S; Handel, Richard W; Almagor, Moshe; Tellegen, Auke
2016-01-01
In this study we examined the utility of the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008/2011; Tellegen & Ben-Porath, 2008/2011) Variable Response Inconsistency-Revised (VRIN-r) and True Response Inconsistency-Revised (TRIN-r) scales, including alternative versions of the scales, in the Hebrew translation of the test. First, we examined the applicability of the U.S. VRIN-r and TRIN-r scales in an Israeli Hebrew-speaking mixed clinical sample, and replaced original item pairs that did not meet the development criteria with substitution item pairs that did. Then, using the Israeli normative sample and a pure clinical sample, we compared the psychometric functioning of the adapted Hebrew-language VRIN-r and TRIN-r scales with that of the original versions of these scales under various conditions of simulated non-content-based (random and fixed) responding. Overall, results showed that the adapted versions of the scales did not improve on the original ones. We therefore recommend using the U.S. VRIN-r and TRIN-r versions, which could also facilitate cross-cultural comparisons.
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Cytogenetic studies in some species of Bromus L., section Genea ...
Indian Academy of Sciences (India)
Unknown
test performed between chromosome number and relative chiasmata values in Bromus species also did not show a significant correlation. Sticky chromosomes. Sticky chromosomes were observed from early stages of prophase and continued to the final stages of meiosis in. Table 1. Meiotic characters in Bromus species ...
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Ecosystem impacts of exotic annual invaders in the genus Bromus
Matthew J. Germino; Jayne Belnap; John M. Stark; Edith B Allen; Benjamin Rau
2016-01-01
An understanding of the impacts of exotic plant species on ecosystems is necessary to justify and guide efforts to limit their spread, restore natives, and plan for conservation. Invasive annual grasses such as Bromus tectorum, B. rubens, B. hordeaceus, and B. diandrus (hereafter collectively referred to as Bromus) transform the structure and function of ecosystems...
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Introduction: Exotic annual Bromus in the western USA [Chapter 1
Matthew J. Germino; Jeanne C. Chambers; Cynthia S. Brown
2016-01-01
The spread and impacts of exotic species are unambiguous, global threats to many ecosystems. A prominent example is the suite of annual grasses in the Bromus genus (Bromus hereafter) that originate from Europe and Eurasia but have invaded or are invading large areas of the Western USA. This book brings a diverse, multidisciplinary group of authors together to...
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An Evaluation of the MMPI-2 and MMPI-A True Response Inconsistency (TRIN) Scales
Handel, Richard W.; Arnau, Randolph C.; Archer, Robert P.; Dandy, Kristina L.
2006-01-01
The Minnesota Multiphasic Personality Inventory--Adolescent (MMPI-A) and Minnesota Multiphasic Personality Inventory--2 (MMPI-2) True Response Inconsistency (TRIN) scales are measures of acquiescence and nonacquiescence included among the standard validity scales on these instruments. The goals of this study were to evaluate the effectiveness of…
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Oxidative stress in bromus seedlings treated with Salvia sclarea L. aqueous extract
Directory of Open Access Journals (Sweden)
Šućur, J.
2016-12-01
Full Text Available Extensive use of synthetic pesticides has negative effects on the environment and on human and animal health. Knowledge on allelopathic interactions could provide effective tools for a better exploitation of natural resources in the management of weeds without using herbicides. One of highly resistant weed species is bromus. The effects of two concentrations (0.1% and 0.2% of Salvia sclarea L. aqueous extract on the activity of the antioxidant enzymes, superoxide dismutase (SOD and catalase (CAT in leaves and roots of bromus (Bromus mollis L. seedlings, were examined. Our results showed that both concentrations of the extract used (0.1% and 0.2% stimulated the significant increase of the superoxide dismutase activity in leaves and roots of bromus 72 hours and 120 hours after the treatment. The significant increase of the catalase activity was recorded in roots of bromus 72 h after the treatment. Two tested extract concentrations affected activity of the antioxidant enzymes in the same way, but the higher activity was observed in the roots treated with higher concentration (0.2%. The increase of the activities of antioxidant enzymes, in response to stress induced by S. sclarea aqueous extract, indicate that the plant extract possesses allelopathic activity on treated plant.
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Brooks, Matthew L.; Brown, Cynthia S.; Chambers, Jeanne C.; D'Antonio, Carla M.; Keeley, Jon E.; Belnap, Jayne
2016-01-01
Exotic annual Bromus species are widely recognized for their potential to invade, dominate, and alter the structure and function of ecosystems. In this chapter, we summarize the invasion potential, ecosystem threats, and management strategies for different Bromus species within each of five ecoregions of the western United States. We characterize invasion potential and threats in terms of ecosystem resistance to Bromus invasion and ecosystem resilience to disturbance with an emphasis on the importance of fi re regimes. We also explain how soil temperature and moisture regimes can be linked to patterns of resistance and resilience and provide a conceptual framework that can be used to evaluate the relative potential for invasion and ecological impact of the dominant exotic annual Bromus species in the western United States.
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Soil moisture and biogeochemical factors influence the distribution of annual Bromus species
Jayne Belnap; John M. Stark; Benjamin M. Rau; Edith B. Allen; Susan Phillips
2016-01-01
Abiotic factors have a strong influence on where annual Bromus species are found. At the large regional scale, temperature and precipitation extremes determine the boundaries of Bromus occurrence. At the more local scale, soil characteristics and climate influence distribution, cover, and performance. In hot, dry, summer-rainfall-dominated deserts (Sonoran, Chihuahuan...
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Energy Technology Data Exchange (ETDEWEB)
L A. DEFALCO; G. C. FERNANDEZ; R. S. NOWAK
2004-01-01
Competition between native and non-native species can change the composition and structure of plant communities, but in deserts the timing of non-native plant establishment can modulate their impacts to native species. In a field experiment, we varied densities of the non-native annual grass Bromus madritensis ssp. rubens around individuals of three native perennials--Larrea iridentata, Achnatherum hymenoides, and Pleuraphis rigida--in either winter or spring. Additional plots were prepared for the Same perennial species and seasons, but with a mixture of native annual species. Relative growth rates of perennial shoots (RGRs) declined with increasing Bromus biomass when Bromus that was established in winter had 2-3 mo of growth and high water use before perennial growth began. However, this high water use did not significantly reduce water potentials for the perennials, suggesting Bromus that established earlier depleted other soil resources, such as N, otherwise used by perennial plants. Spring-established Bromus had low biomass even at higher densities and did not effectively reduce RGRs, resulting in an overall lower impact to perennials than when Bromus was established in winter. Similarly, growth and reproduction of perennials with mixed annuals as neighbors did not differ from those with Bromus neighbors of equivalent biomass, but densities of these annuals did not support the high biomass necessary to reduce perennial growth. Thus, impacts of native Mojave Desert annuals to perennials are expected to be lower than those of Bromus because seed dormancy and narrow requirements for seedling survivorship produce densities and biomass lower than those achieved by Bromus. In comparing the effects of Bromus among perennial species, the impact of increased Bromus biomass on RGR was lower for Larrea than for the two perennial grasses, probably because Lurrea maintains low growth rates throughout the year, even after Bromus has completed its life cycle. This contrasts
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Mechanisms controlling the distribution of two invasive Bromus species
Directory of Open Access Journals (Sweden)
Olga Bykova
2014-03-01
Full Text Available In order to predict future range shifts for invasive species it is important to explore their ability to acclimate to the new environment and understand physiological and reproductive constraints controlling their distribution. My dissertation studied mechanisms by which temperature may affect the distribution of two aggressive plant invaders in North America, Bromus tectorum and Bromus rubens. I first evaluated winter freezing tolerance of Bromus species and demonstrated that the mechanism explaining their distinct northern range limits is different acquisition time of freezing tolerance. While B. rubens has a slower rate of freezing acclimation that leads to intolerance of sudden, late-autumn drops in temperature below -12°C, B. tectorum rapidly hardens and so is not impacted by the sudden onset of severe late-autumn cold. In addition, the analysis of male reproductive development and seed production showed that neither species produces seed at or above 36°C, due to complete pollen sterility, which might trigger climate-mediated range contractions at B. tectorum and B. rubens southern margins. Finally, a detailed gas-exchange analysis combined with biochemical modelling demonstrated that both species acclimate to a broad range of temperatures and photosynthetic response to temperature does not explain their current range separation.
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Bromus interruptus (Hack.) Druce (Poaceae) in Nederland
Rich, Tim C.G.
2001-01-01
Bromus interruptus is a grass which was endemic to England but is now extinct in the wild. Attention is drawn to the two historic records from the Netherlands, where it was probably introduced with agricultural seed, in case it still survives in the wild. It is readily recognised from the contracted
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Hydrothermal emergence model for ripgut brome (Bromus diandrus)
A model that describes the emergence of ripgut brome (Bromus diandrus) was developed using a two-season data set from a no-tilled field in northeastern Spain. The relationship between cumulative emergence and hydrothermal time (HTT) was described by a sigmoid growth function (Chapman equation). HTT ...
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Seed ecology of Bromus sterilis L.
Directory of Open Access Journals (Sweden)
Žďárková, Veronika
2014-02-01
Full Text Available Bromus sterilis L. (barren brome has become a troublesome weed of winter cereals in reduced tillage systems, mainly in South and North America, middle and Western Europe. In the Czech Republic, its importance has increased dramatically over the past 10 years. Barren brome is reported as a problem weed in other winter crops such as oil seed rape, in vineyards and in other cultivated places. In this study, the dormancy and germination under different temperatures, water and light regimes were investigated. Emergence from different depths and persistence in the soil profile were investigated under field conditions. The seeds of Bromus sterilis showed broad ecological valence to hydrothermal factors germinating in the wide range of 5 to 35 °C. Similarly, no strong effect on the germination in an environment with low water potential was observed. The response to light at various temperatures showed that seeds germinated better in darkness. The emergence declined significantly with burial depth (under 40 mm. The loss of primary dormancy was rapid in time and only 50% of the seeds germinated within 8 weeks after collecting from maternal plants. The seeds were not able to survive in the soil seed bank for a longer time and fall seeds lost viability 1 year after burial in a soil profile.
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Matthew L. Brooks; Cynthia S. Brown; Jeanne C. Chambers; Carla M. D' Antonio; Jon E. Keeley; Jayne Belnap
2016-01-01
Exotic annual Bromus species are widely recognized for their potential to invade, dominate, and alter the structure and function of ecosystems. In this chapter, we summarize the invasion potential, ecosystem threats, and management strategies for different Bromus species within each of five ecoregions of the western United States. We characterize invasion...
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Energy Technology Data Exchange (ETDEWEB)
Correa, Marivaldo J.C.; Nunes, Fatima M.; Bitencourt, Heriberto R.; Borges, Fabio C.; Guilhon, Giselle M.S.P.; Arruda, Mara S.P.; Marinho, Andrey M. R.; Santos, Alberdan S.; Alves, Claudio N.; Santos, Lourivaldo S., E-mail: lss@ufpa.b [Universidade Federal do Para (IQ/FEQ/UFPA), Belem, PA (Brazil). Inst. de Tecnologia. Faculdade de Engenharia Quimica; Brasil, Davi S.B. [Universidade Federal do Para (PPGQ/IQ/UFPA), Belem, PA (Brazil). Inst. de Quimica. Programa de Pos-Graduacao em Quimica
2011-07-01
The fungus Aspergillus flavus isolated as endophytic of the plant Paspalum maritimum Trin. was evaluated for its potential application in biotransformation reactions. The compounds chalcone (1), 3,4,5-trimethoxychalcone (2) and 2,3,4,4'-tetramethoxy chalcone (3) were biotransformed, respectively, in dihydrochalcone (4), 3,4,5-trimethoxydihydrochalcone (5) and 2,3,4,4'-tetramethoxydihydrochalcone (6). The structures were elucidated by spectroscopic methods including 1D and 2D NMR techniques, and MS analysis. The dihydrochalcones 5 and 6 are new compounds. (author)
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International Nuclear Information System (INIS)
Correa, Marivaldo J.C.; Nunes, Fatima M.; Bitencourt, Heriberto R.; Borges, Fabio C.; Guilhon, Giselle M.S.P.; Arruda, Mara S.P.; Marinho, Andrey M. R.; Santos, Alberdan S.; Alves, Claudio N.; Santos, Lourivaldo S.; Brasil, Davi S.B.
2011-01-01
The fungus Aspergillus flavus isolated as endophytic of the plant Paspalum maritimum Trin. was evaluated for its potential application in biotransformation reactions. The compounds chalcone (1), 3,4,5-trimethoxychalcone (2) and 2,3,4,4'-tetramethoxy chalcone (3) were biotransformed, respectively, in dihydrochalcone (4), 3,4,5-trimethoxydihydrochalcone (5) and 2,3,4,4'-tetramethoxydihydrochalcone (6). The structures were elucidated by spectroscopic methods including 1D and 2D NMR techniques, and MS analysis. The dihydrochalcones 5 and 6 are new compounds. (author)
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Community ecology of fungal pathogens on Bromus tectorum [Chapter 7
Susan E. Meyer; Julie Beckstead; JanaLynn Pearce
2016-01-01
Bromus tectorum L. (cheatgrass or downy brome) presents a rich resource for soil microorganisms because of its abundant production of biomass, seeds, and surface litter. Many of these organisms are opportunistic saprophytes, but several fungal species regularly found in B. tectorum stands function as facultative or obligate pathogens. These organisms interact...
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Ecological genetics of floret mass variation in Bromus tectorum (Poaceae)
Susan E. Meyer
2010-01-01
Bromus tectorum L. (cheatgrass, downy brome) is a highly invasive inbreeding annual grass that dominates millions of hectares of former shrubland in interior western North America. Factors contributing to its success include strong genetic regulation of key adaptive traits coupled with high phenotypic plasticity in response to resource availability (Meyer and Allen...
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Handel, Richard W.; Ben-Porath, Yossef S.; Tellegen, Auke; Archer, Robert P.
2010-01-01
In the present study, the authors evaluated the effects of increasing degrees of simulated non-content-based (random or fixed) responding on scores on the newly developed Variable Response Inconsistency-Revised (VRIN-r) and True Response Inconsistency-Revised (TRIN-r) scales of the Minnesota Multiphasic Personality Inventory-2 Restructured Form…
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Factors affecting Bromus tectorum seed bank carryover in western Utah
Duane C. Smith; Susan E. Meyer; V. J. Anderson
2008-01-01
Cheatgrass (Bromus tectorum L.) is a winter annual weed that presents a serious obstacle to rangeland restoration in the Intermountain West. The objective of this study was to evaluate factors regulating the size and persistence of cheatgrass carryover seed banks on semiarid sites in western Utah. We prevented current-year seed production in each of...
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Directory of Open Access Journals (Sweden)
M. Rezaei
2018-02-01
Full Text Available Bromus danthoniae Trin. is an annual grass species that is well adapted to harsh climates and could be considered as an important genetic resources for tolerance to environmental stresses such as salinity. In this study, 24 genotypes collected from Ilam, Kurdistan, Kermanshah (non-saline areas and West Azerbaijan (saline area: shores of Uremia Salt Lake provinces of Iran were investigated at the germination stage under salt treatments with concentrations of 0, 60, 120, 180, 240 and 300 mM sodium chloride. Germination percentage, germination rate index, seed vigor, root length, shoot length and seedling fresh and dry weights were measured. In addition, the relationship between the percentage of germination in 300 mM sodium chloride and the survival rate (% after four weeks in 350 mM sodium chloride at the vegetative stage was evaluated. The results of analysis of variance showed that salinity treatments caused significant reductions in all the studied traits. Genotypic variation and the interaction of genotype × salt treatments were also significant. Genotypes USLN3 and KER4 were found to be the most tolerant and sensitive genotypes to salinity stress, with 13% and 98% reduction in germination percentage at 300 mM NaCl, respectively. Cluster analysis divided the genotypes into three groups, with one group containing only tolerant genotypes from Uremia Salt Lake, another one comprising only sensitive genotypes from non-saline regions, and the third one containing genotypes from both regions. The correlation between the germination percentage and the survival rate at the vegetative stage was not significant, indicating that different mechanisms are, perhaps, responsible for salinity tolerance at the germination and vegetative stages in B. danthoniae.
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Bromus tectorum L. invasion: Changes in soil properties and rates of bioturbation
Bromus tectorum (cheatgrass, downy brome), an exotic annual grass of Eurasian origin, has replaced native Artemisia/bunchgrass communities on millions of hectares throughout the Intermountain West. Using Jenny’s (1941) framework that specific vegetation can differentially affect soil development; we...
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Effects of growth regulator herbicide on downy brome (Bromus tectorum) seed production
Previous research showed growth regulator herbicides, such as picloram and aminopyralid, have a sterilizing effect on Japanese brome (Bromus japonicus Thunb.) that can reduce this invasive annual grass’s seed production nearly 100%. This suggests growth regulators might be used to control invasive ...
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Inbreeding, Genetic Variation, and Invasiveness: The Strange Case of Bromus tectorum
Susan E. Meyer; Elizabeth A. Leger
2010-01-01
Cheatgrass (Bromus tectorum, downy brome) is arguably the most common plant in the western United States, dominating literally millions of acres of degraded rangeland; yet it is a relative newcomer, having arrived on the scene only a little over a century ago. It first entered the West as an unknown but probably small number of seeds in contaminated grain or packing...
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Bromus carinatus Hook. et Arn. en Puccinellia distans (L.) Parl. in Midden-Nederland
Floristenclub Gelderse Vallei,
1979-01-01
The authors mention the occurrence of two grasses, Bromus carinatus Hook, et Arn. (fig. 1) and Puccinellia distans (L.) Parl. (fig. 2) in the central part of the Netherlands. The first is a naturalised adventitious plant, the other a species of saline habitats and is spreading through this part of
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Population genetic structure of Bromus tectorum in the mountains of western North America
Spencer Arnesen; Craig E. Coleman; Susan E. Meyer
2017-01-01
PREMISE OF THE STUDY: Invasive species are often initially restricted to a narrow range and may then expand through any of multiple mechanisms including phenotypic plasticity, in situ evolution, or selection on traits preadapted for new habitats. Our study used population genetics to explore possible processes by which the highly selfing invasive annual grass Bromus...
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S. E. Meyer; D. L. Nelson; S. Clement
2001-01-01
Bromus tectorum L. (cheatgrass or downy brome) is an important exotic weed in natural ecosystems as well as in winter cereal cropland in semiarid western North America. The systemic, seedling-infecting head smut pathogen Ustilago bullata Berk. commonly infects cheatgrass stands, often at epidemic levels. We examined factors...
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Alisa P. Ramakrishnan; Susan Meyer; Daniel J. Fairbanks; Craig E. Coleman
2006-01-01
Bromus tectorum (cheatgrass or downy brome) is an exotic annual weed that is abundant in western USA. We examined variation in six microsatellite loci for 17 populations representing a range of habitats in Utah, Idaho, Nevada and Colorado (USA) and then intensively sampled four representative populations, for a total sample size of approximately 1000 individuals. All...
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Land uses, fire, and invasion: Exotic annual Bromus and human dimensions [Chapter 11
David A. Pyke; Jeanne C. Chambers; Jeffrey L. Beck; Matthew L. Brooks; Brian A. Mealor
2016-01-01
Human land uses are the primary cause of the introduction and spread of exotic annual Bromus species. Initial introductions were likely linked to contaminated seeds used by homesteading farmers in the late 1880s and early 1900s. Transportation routes aided their spread. Unrestricted livestock grazing from the 1800s through the mid-1900s reduced native plant competitors...
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Lea Condon; Peter J. Weisberg; Jeanne C. Chambers
2011-01-01
Native sagebrush ecosystems in the Great Basin (western USA) are often invaded following fire by exotic Bromus tectorum (cheatgrass), a highly flammable annual grass. Once B. tectorum is established, higher fire frequencies can lead to local extirpation of Artemisia tridentata ssp. vaseyana (mountain big sagebrush) and have cascading effects on sagebrush ecosystems and...
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Directory of Open Access Journals (Sweden)
Małgorzata Haliniarz
2014-01-01
Full Text Available The aim of the present study was to compare the germination of rye brome (Bromus secalinus L. seeds and the initial growth of seedlings under simulated drought and different thermal conditions. The study included two experiments carried out under laboratory conditions in the spring of 2012. The first experiment involved an evaluation of the speed of germination as well as of the biometric characters and weight of seedlings in polyethylene glycol solutions (PEG 8000 in which the water potential was: -0.2; -0.4; -0.65; -0.9 MPa, and in distilled water as the control treatment. The experiment was conducted at the following temperatures: 25/22oC and 18/14oC day/night, at a relative air humidity of 90%. The other experiment, in which lessive soil was used as a germination substrate, was carried out in a plant growth chamber at two levels of air humidity (55–65% and 85–95% and temperature (22/10oC and 16/5oC. The soil moisture content was determined by the gravimetric method and the water potential corresponding to it was as follows: -0.02, -0.07, -0.16, -0.49, -1.55 MPa. The germination capacity and emergence of Bromus secalinus as well as the weight of sprouts produced were significantly dependent on the water potential of the polyethylene glycol solution and on the soil water potential. The emergence of Bromus secalinus was completely inhibited by reducing the soil water potential below -0.16 MPa (the point of strong growth inhibition. The emergence and biometric characters of rye bro- me seedlings were significantly dependent on temperature and air humidity.
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Fire effects on the mobilization and uptake of nitrogen by cheatgrass (Bromus tectorum L.)
Brittany G. Johnson; Dale W. Johnson; Jeanne C. Chambers; Robert R. Blank
2011-01-01
Cheatgrass (Bromus tectorum L.), an invasive annual grass, is displacing native species and causing increased fire frequency in the Great Basin of the southwestern United States. Growth and nitrogen uptake patterns by cheatgrass were examined in a greenhouse study using soils from sites with the same soil type but different fire histories: 1) an area that burned in...
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Elizabeth A. Leger; Erin K. Espeland; Keith R. Merrill; Susan E. Meyer
2009-01-01
Cheatgrass (Bromus tectorum) is an invasive weed in western North America found primarily growing at elevations less than 2200 m. We asked whether cheatgrass is capable of becoming adapted to a marginal habitat, by investigating a population at a high elevation invasion edge. We used a combination of methods, including reciprocal field transplants, controlled...
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Susan E. Meyer; David L. Nelson; Suzette Clement; Alisa Ramakrishnan
2010-01-01
Evolutionary processes that maintain genetic diversity in plants are likely to include selection imposed by pathogens. Negative frequency-dependent selection is a mechanism for maintenance of resistance polymorphism in plant - pathogen interactions. We explored whether such selection operates in the Bromus tectorum - Ustilago bullata pathosystem. Gene-for-gene...
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Does Fusarium-caused seed mortality contribute to Bromus tectorum stand failure in the Great Basin?
S. E. Meyer; J.-L. Franke; O. W. Baughman; J. Beckstead; B. Geary
2014-01-01
Bromus tectorum (cheatgrass, downy brome) is an important invader in western North America, dominating millions of hectares of former semi-arid shrubland. Stand failure or 'die-off' is relatively common in monocultures of this annual grass. The study reported here investigated whether soil-borne pathogens could be causal agents in die-offs. Soils from two die...
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JanaLynn Franke; Brad Geary; Susan E. Meyer
2014-01-01
The genus Fusarium has a wide host range and causes many different forms of plant disease. These include seed rot and seedling blight diseases of cultivated plants. The diseases caused by Fusarium on wild plants are less well-known. In this study, we examined disease development caused by Fusarium sp. n on nondormant seeds of the important rangeland weed Bromus...
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R.C. Johnson; Vicky J. Erickson; Nancy L. Mandel; J. Bradley St. Clair; Kenneth W. Vance-Borland
2010-01-01
Seed transfer zones ensure that germplasm selected for restoration is suitable and sustainable in diverse environments. In this study, seed zones were developed for mountain brome (Bromus carinatus Hook. & Arn.) in the Blue Mountains of northeastern Oregon and adjoining Washington. Plants from 148 Blue Mountain seed source locations were...
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Keith R. Merrill; Susan E. Meyer; Craig E. Coleman
2012-01-01
The mechanisms for range expansion in invasive species depend on how genetic variation is structured in the introduced range. This study examined neutral genetic variation in the invasive annual grass Bromus tectorum in the Intermountain Western United States. Patterns of microsatellite (SSR) genotype distribution in this highly inbreeding species were used to make...
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Directory of Open Access Journals (Sweden)
Ana M. García
2009-01-01
Full Text Available Bromus setifolius var. pictus (Hook Skottsb., B. setifolius var. setifolius Presl. and B. setifolius var. brevifolius Ness are three native Patagonian taxa in the section Pnigma Dumort of the genus Bromus L. AFLP and RAPD analysis, in conjunction with genetic distance measurements and statistical techniques, revealed variation within this group and indicated that B. setifolius var. brevifolius was closely related to B. setifolius var. pictus, with both taxa being more distantly related to B. setifolius var. setifolius. Cytogenetic analysis confirmed the chromosomal number of B. setifolius var. pictus (2n = 70 and B. setifolius var. setifolius (2n = 28 and showed for the first time that B. setifolius var. brevifolius had 2n = 70. The combination of molecular genetic and cytogenetic evidence supported a species status for two of the three taxa and suggested hypotheses for the evolutionary origin of these complex taxa. Species status was also indicated for B. setifolius var. setifolius. Based on these findings, we suggest that B. setifolius var. pictus be referred to as B. pictus Hook var. pictus, and B. setifolius var brevifolius as B. pictus Hook var brevifolius. The correlation between AFLP diversity and variation in ecological parameters suggested that this marker system could be used to assess breeding progress and to monitor the domestication of Patagonian Bromus species for agronomic use.
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Alison Whittaker; Bruce Roundy; Jeanne Chambers; Susan Meyer; Robert Blank; Stanley Kitchen; John Korfmacher
2008-01-01
Over the past several decades, cheatgrass (Bromus tectorum) has been continually expanding in the sagebrush steppe ecosystem. There has been very little research that examines why cheatgrass is able to invade these communities. To determine the effects of herbaceous vegetation removal and fire on available water for cheatgrass invasion, as well as...
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Directory of Open Access Journals (Sweden)
Deddy Dharmaji
2016-09-01
Full Text Available This research was aimed analyze the ability of perupuk (Phragmites karka Trin in reducing of rubber industrial liquid waste polluters on the scale of the laboratory. The method used was the method of survey. The data laboratory test were tabulated and analyzed descriptively and the level of efficiency was calculated. Referring to South Kalimantan Governor Regulation Number 36/2008, the results showed that, TSS parameters started to be effectively reduced on day 10 with close to 84,33 mg/l (32.53%, BOD5 started to be effectively reduced on day 20 with close to 24.00 mg/l (99,29%, and COD started to be effectively reduced on day 20 with close to 44,65 mg/l (98,90%. Referring to the decision of the Minister of Environment No. KEP-78/MENLH/10/1995, the parameters of the Sulfide started to be effectively reduced on day 10 with close to 0.001 mg/l (93,75% and Manganese start to be effectively reduced on day 20 with close to 0,70 mg/l (-134,00 %. Ph levels and temperature still normal condition. Time retention was best accomplished on day 30 in reducing liquid waste rubber industry.
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Susan E. Meyer; Elizabeth A. Leger; Desiree R. Eldon; Craig E. Coleman
2016-01-01
Bromus tectorum, an inbreeding annual grass, is a dominant invader in sagebrush steppe habitat in North America. It is also common in warm and salt deserts, displaying a larger environmental tolerance than most native species. We tested the hypothesis that a suite of habitat-specific B. tectorum lineages dominates warm desert habitats. We sampled 30 B....
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Brooks, Matthew L.; Hondo Brisbin, graduate student; Andrea Thode, Associate Professor; Karen Weber, graduate student
2013-01-01
The continued threat of an invasive, annual brome (Bromus) species in the western United States has created the need for integrated approaches to postfire restoration. Additionally, the high germination rate, high seed production, and seed bank carryover of annual bromes points to the need to assay soil seed banks as part of monitoring programs. We sampled the soil seed bank to help assess the effectiveness of treatments utilizing the herbicide Plateau® (imazapic) and a perennial native seed mix to control annual Bromus species and enhance perennial native plant establishment following a wildfire in Zion National Park, Utah. This study is one of few that have monitored the effects of imazapic and native seeding on a soil seed bank community and the only one that we know of that has done so in a pinyon–juniper woodland. The study made use of untreated, replicated controls, which is not common for seed bank studies. One year posttreatment, Bromus was significantly reduced in plots sprayed with herbicide. By the second year posttreatment, the effects of imazapic were less evident and convergence with the controls was evident. Emergence of seeded species was low for the duration of the study. Dry conditions and possible interactions with imazapic probably contributed to the lack of emergence of seeded native species. The perennial grass sand dropseed outperformed the other species included in the seed mix. We also examined how the treatments affected the soil seed bank community as a whole. We found evidence that the herbicide was reducing several native annual forbs and one nonnative annual forb. However, overall effects on the community were not significant. The results of our study were similar to what others have found in that imazapic is effective in providing a short-term reduction in Bromus density, although it can impact emergence of nontarget species.
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Marco Masia; Susan Meyer; Suzette Clement; Anna Andolfi; Alessio Cimmino; Antonio. Evidente
2014-01-01
A novel spirocyclic γ-lactam, named spirostaphylotrichin W (1), was isolated together with the well known and closely related spirostaphylotrichins A, C, D, R and V, as well as triticone E, from the liquid cultures of Pyrenophora semeniperda (anamorph: Drechslera), a seed pathogen proposed for cheatgrass (Bromus tectorum) biocontrol. Spirostaphylotrichin W was...
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Directory of Open Access Journals (Sweden)
Arturi, Miguel J.
2008-06-01
Full Text Available Thirty-one populations of Bromus catharticus Vahl., collected from the Pampean Dominion (Argentina, were classified using twenty four highly heritable traits by numerical taxonomic methods. After implementing a stepwise discriminant analysis, 18 traits were chosen as classificatory variables. Eight population groups were classified in two main clusters. Different morphotypes, primarily associated with panicle architecture and micro floral traits, were found. The patterns in the morphological variation seem to correspond to a gradient of humidity and temperature that diminishes from the NE to the SW. This pattern of classification reflects the geographical origin for most of the sampled populations, although there was some noise. Our results fit the patchy variation model, where populations are genetically selected for macro and micro environmental conditions.Treinta y una poblaciones de Bromus catharticus Vahl., recolectadas en el dominio Pampeano (Argentina, fueron clasificadas utilizando 24 caracteres altamente heredables por métodos de taxonomía numérica. Tras implementar el análisis discriminante del paso a paso (Stepwise, 18 variables fueron seleccionadas como variables clasificatorias. Ocho grupos de poblaciones fueron clasificadas en dos clusters principales. Diferentes morfotipos, principalmente asociados a la arquitectura de las panojas y a variables microflorales, fueron encontrados. El patrón de variación morfológico parece responder a un gradiente de humedad y temperatura que disminuye desde el NE al SW. Además, dicho patrón de clasificación refleja un origen geográfico para la mayoría de las poblaciones, aunque hubo algo de ruido. Nuestros resultados se ajustan a un modelo de variación en parches, donde las poblaciones están genéticamente seleccionadas por condiciones micro y macro ambientales.
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Directory of Open Access Journals (Sweden)
Agnieszka Sutkowska
2012-10-01
Full Text Available ‘Broma’ is a grass cultivar belonging to the species Bromus carinatus. In the Lists of Agricultural Plant Varieties of the Research Centre for Cultivar Testing (COBORU, it is shown as Bromus willdenowii (= B. catharticus, B. unioloides (List of Agricultural Plant Varieties 1989-2009, whereas already in 1984 Mirek demonstrated on the basis of morphological analysis that this was a different closely related species – B. carinatus. The aim of the present study was to verify the species affiliation of cv. ‘Broma’. The conducted analysis of ISSR molecular markers included representatives of cv. ‘Broma” as well as of B. carinatus and B. willdenowii. The method used allowed the identification of molecular markers of the above-mentioned taxa. The numerical analysis of the obtained results suggests that cv. ‘Broma’ should be classified in the species B. carinatus, not B. willdenowii.
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Herbicide spring treatments for the control of brome grasses (Bromus spp. in winter cereals
Directory of Open Access Journals (Sweden)
Gehring, Klaus
2014-02-01
Full Text Available The efficacy of different ALS-inhibiting herbicides for the control of brome species (Bromus spp. was tested in three field trials in the year 2010 – 2012 in the region of North-West-Bavaria Franken. As a result of the trials the standard herbicide Attribut (Propoxycarbazone was confirmed for the control of brome. In case of infestation with brome and black grass the herbicide Broadway (Pyroxsulam offers a certain control of both problematic grass weeds. This illustrates the high dependency of sufficient brome control in winter cereals on the effectiveness of specific ALS-Inhibitor herbicides. Because of the high risk of herbicide resistance to ACCaseand ALS-inhibiting herbicides in brome, integrated weed management is essential for the sustainable control of brome in winter cereals, respectively winter wheat.
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Directory of Open Access Journals (Sweden)
Muhammad Asghar
2017-06-01
Full Text Available A field experiment was conducted to evaluate the efficacy of different post emergence herbicides for the control of monocot weed the Japanese broom (Bromus japonicus in wheat crop. Five herbicides viz., metribuzin, isoproturon, metribuzin plus isoproturon, Atlantis and sulfosulfuron were used at their recommended doses in RCBD with three replications. The weedy check was kept as control where no herbicide was sprayed. All the herbicides were applied as post-emergence after second irrigation at 60 days after sowing the crop. The lowest weed counts per m2 (0.583 and highest percent of weed mortality (99.07% were observed where metribuzin plus isoproturon was used. This was followed by Atlantis with 3.26 weeds per m2 with 95.14% mortality of weeds. However, significantly higher 1000 grain weight was noted with Atlantis (29.50 g and metribuzin plus isoproturon (28.58 g. The treatments did not differ significantly with respect to 1000 grain weight. All the herbicide helped to increase the yield from 16 to 22%, but did not differ significantly with respect to yield gain. The highest yield (3759.40 kg ha-1 was produced by Atlantis followed by sulfosulfuron (3757.20 kg ha-1 . On the basis of cost benefit ratio sulfosulfuron (34.95 proved to be the best followed by metribuzin (16.78. Therefore, sulfosulfuron and metribuzin are recommended for the control of Bromus weed in wheat crop.
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Gu, Wen; Reddy, Hima B; Green, Debbie; Belfi, Brian; Einzig, Shanah
2017-01-01
Criminal forensic evaluations are complicated by the risk that examinees will respond in an unreliable manner. Unreliable responding could occur due to lack of personal investment in the evaluation, severe mental illness, and low cognitive abilities. In this study, 31% of Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008/2011) profiles were invalid due to random or fixed-responding (T score ≥ 80 on the VRIN-r or TRIN-r scales) in a sample of pretrial criminal defendants evaluated in the context of treatment for competency restoration. Hierarchical regression models showed that symptom exaggeration variables, as measured by inconsistently reported psychiatric symptoms, contributed over and above education and intellectual functioning in their prediction of both random responding and fixed responding. Psychopathology variables, as measured by mood disturbance, better predicted fixed responding after controlling for estimates of cognitive abilities, but did not improve the prediction for random responding. These findings suggest that random responding and fixed responding are not only affected by education and intellectual functioning, but also by intentional exaggeration and aspects of psychopathology. Measures of intellectual functioning and effort and response style should be considered for administration in conjunction with self-report personality measures to rule out rival hypotheses of invalid profiles.
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Ecological Genetics of Vernalization Response in Bromus tectorum L. (Poaceae)
MEYER, SUSAN E.; NELSON, DAVID L.; CARLSON, STEPHANIE L.
2004-01-01
• Background and Aims Bromus tectorum (cheatgrass or downy brome) is an exotic annual grass that is dominant over large areas of former shrubland in western North America. To flower in time for seed production in early summer, B. tectorum plants generally require vernalization at winter temperatures, either as imbibed seeds or as established seedlings. • Methods Variation in response to increasing periods of vernalization as seeds or seedlings for progeny of ten full‐sib families from each of four B. tectorum populations from contrasting habitats was studied. • Key Results As vernalization was increased from 0 to 10 weeks, the proportion of plants flowering within 20 weeks increased, weeks to initiation of flowering decreased, and seed yield per plant increased, regardless of whether plants were vernalized as seeds or seedlings. Most of the variation was accounted for by differences among populations. Plants of the warm desert population flowered promptly even without vernalization, while those of the cold desert, foothill and montane populations showed incremental changes in response variables as a function of vernalization period. Populations differed in among‐family variance, with the warm desert population generally showing the least variance and the cold desert population the most. Variation among populations and among families within populations decreased as vernalization period increased, whereas the non‐genetic component of variance showed no such pattern. • Conclusions Variation in vernalization response was found to be adaptively significant and apparently represents the result of contrasting selection regimes on a range of founder genotypes. PMID:15087300
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Krimiens filosofiske undersøgelser
DEFF Research Database (Denmark)
Hansen, Kim Toft
I denne artikel tager Kim Toft Hansen over tre trin fat på Henning Mortensens forfatterskab og primært dennes såkaldte Sondrup-trilogi. Første trin bliver at præcisere, hvordan Mortensen metafiktivt dekonstruerer krimiens form. Andet trin analyserer Mortensens samfundskritik, der dukker op trods ...... dekonstruerende elementer. Tredje og sidste trin fokuserer på de filosofiske implikationer i Mortensens eksplicitte brug af Ludwig Wittgensteins filosofi....
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Recherches philosophiques et roman policier
DEFF Research Database (Denmark)
Hansen, Kim Toft
2010-01-01
I denne artikel tager Kim Toft Hansen over tre trin fat på Henning Mortensens forfatterskab og primært dennes såkaldte Sondrup-trilogi. Første trin er at præcisere, hvordan Mortensen metafiktivt dekonstruerer krimiens form. Andet trin analyserer Mortensen samfundskritik, der dukker op trods de...
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Directory of Open Access Journals (Sweden)
Araújo Marcelo Renato Alves de
2004-01-01
Full Text Available Meadow bromegrass (Bromus riparius Rehm. is a recently introduced pasture grass in western Canada. Its leafy production and rapid regrowth have made it a major grass species for pasturing beef animals in this region. As relatively little breeding work has been done on this species, there is little information on its breeding behaviour. The main objective of this study was to estimate total genetic variability, broad-sense heritability, phenotypic and genetic correlations. Forty-four meadow bromegrass clones were evaluated for agronomic characters. Genetic variation for dry matter yield, seed yield, fertility index, harvest index, plant height, plant spread, crude protein, neutral detergent fiber and acid detergent fiber, was significant. Broad-sense heritability estimates exceeded 50% for all characters. Heritability estimates were at least 3.5 times greater than their standard errors. Phenotypic and genetic correlation between all possible characters were measured. There was general agreement in both sign and magnitude between genetic and phenotypic correlations. Correlations between the different characters demonstrated that it is possible to simultaneously improve seed and forage yield. Based on the results, it appears that the development of higher yielding cultivars with higher crude protein, and lower acid and neutral detergent fibers concentration should be possible.
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Energy Technology Data Exchange (ETDEWEB)
Cerne, Marko, E-mail: marko.cerne@ijs.s [Jozef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Smodis, Borut, E-mail: borut.smodis@ijs.s [Jozef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Strok, Marko, E-mail: marko.strok@ijs.s [Jozef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia)
2011-04-15
From uranium mining areas, in particular, the radionuclides are usually discharged to the environment during the mining and milling process. At the former uranium mine Zirovski vrh, Slovenia, mine waste and mill tailings were deposited at the Jazbec site and the Borst site, respectively. Plants grown in soils contaminated with the seepage waters from tailings may represent radiological concern if radionuclides from the uranium decay chain are transferred into the food chain. Uranium is usually accumulated in the roots and translocated to the shoots in limited amounts. Uranium plant accumulators are usually plants from Brassicaceae and Poaceae families. A common reed (Phragmites australis (Cav.) Trin. ex Steud.), a tall perennial grass, growing in a wetland habitats, accumulates metals in the above-ground parts. It may be used for phytoremediation of uranium-contaminated soils, because of high biomass production and high metal-accumulation potential. Preliminary results of radionuclide contents measured in such plants, growing on the deposit tailings are presented. A common reed, that was grown on the Borst tailings pile accumulated 8.6 {+-} 8 mBq/g dry weight (d.w.) and 2.4 {+-} 2 mBq/g dry weight (d.w.) of {sup 238}U in leaves and stems, respectively. In the paper, activity concentrations of other nuclides, i.e. {sup 226}Ra, {sup 210}Pb and {sup 40}K are also shown and discussed.
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Warming, soil moisture, and loss of snow increase Bromus tectorum’s population growth rate
Directory of Open Access Journals (Sweden)
Aldo Compagnoni
2014-01-01
Full Text Available Abstract Climate change threatens to exacerbate the impacts of invasive species. In temperate ecosystems, direct effects of warming may be compounded by dramatic reductions in winter snow cover. Cheatgrass (Bromus tectorum is arguably the most destructive biological invader in basins of the North American Intermountain West, and warming could increase its performance through direct effects on demographic rates or through indirect effects mediated by loss of snow. We conducted a two-year experimental manipulation of temperature and snow pack to test whether 1 warming increases cheatgrass population growth rate and 2 reduced snow cover contributes to cheatgrass’ positive response to warming. We used infrared heaters operating continuously to create the warming treatment, but turned heaters on only during snowfalls for the snowmelt treatment. We monitored cheatgrass population growth rate and the vital rates that determine it: emergence, survival and fecundity. Growth rate increased in both warming and snowmelt treatments. The largest increases occurred in warming plots during the wettest year, indicating that the magnitude of response to warming depends on moisture availability. Warming increased both fecundity and survival, especially in the wet year, while snowmelt contributed to the positive effects of warming by increasing survival. Our results indicate that increasing temperature will exacerbate cheatgrass impacts, especially where warming causes large reductions in the depth and duration of snow cover.
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Effects of high fire frequency in creosote bush scrub vegetation of the Mojave Desert
Brooks, M.L.
2012-01-01
Plant invasions can increase fire frequency in desert ecosystems where fires were historically infrequent. Although there are many resource management concerns associated with high frequency fire in deserts, fundamental effects on plant community characteristics remain largely unstudied. Here I describe the effects of fire frequency on creosote bush scrub vegetation in the Mojave Desert, USA. Biomass of the invasive annual grass Bromus rubens L. increased following fire, but did not increase further with additional fires. In contrast, density, cover and species richness of native perennial plants each decreased following fire and continued to decrease with subsequent fires, although not as dramatically as after the initial fire. Responses were similar 5 and 14 years post-fire, except that cover of Hymenoclea salsola Torr. & A. Gray and Achnatherum speciosa Trin. & Rupr. both increased in areas burnt once. These results suggest that control of B. rubens may be equally warranted after one, two or three fires, but revegetation of native perennial plants is most warranted following multiple fires. These results are valid within the scope of this study, which is defined as relatively short term vegetation responses (???14 years) to short fire return intervals (6.3 and 7.3 years for the two and three fire frequency levels) within creosote bush scrub of the Mojave Desert. ?? 2012 IAWF.
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First record of target-site-resistance of poverty brome (Bromus sterilis to ACCase inhibitors
Directory of Open Access Journals (Sweden)
Dicke, Dominik
2014-02-01
Full Text Available In 2011 reduced efficacy of grass weed herbicides to poverty brome (Bromus sterilis was observed in oilseed rape on a site in East Hessen. The field was cultivated by using the ploughless tillage system more than 25 years. The site showed high densities of poverty brome (>1000 plants/m² prior to herbicide treatment. Poverty brome seeds were collected in 2012 in the hessian oilseed rape field and from a site in East Westphalia, where poverty brome appeared at low densities (10 plants/m² and was not suspected to resistance. The seeds were sown in to pots and plants cultivated. The plants were treated with two application rates (normal dose, double dose with herbicides of different HRAC-classes. The time of treatment was adjusted to the best expectable treatment/efficiency conditions of the individual herbicides (see chapter 3. Clear differences in efficacy that were caused by herbicide, the origins of poverty brome and the dosages were recorded via visual rating eight weeks after spraying. The herbicides Agil and Focus Ultra were able to control about 90% of the poverty brome plants of the East Westphalia site origin. However, only 20-30% of the Hessian plants could be knocked out by the same herbicides. The ACCase-gene of single powerty brome leaf samples from the hessian site was analyzed after resistance assessment. A molecular genetic analysis on 7 variable positions identified target site resistance: Isoleucine (Ile was replaced by asparagine (Asn at position 2041.
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Masi, Marco; Meyer, Susan; Pescitelli, Gennaro; Cimmino, Alessio; Clement, Suzette; Peacock, Beth; Evidente, Antonio
2017-12-01
The winter annual grass Bromus tectorum (cheatgrass) has become highly invasive in semiarid ecosystems of western North America. In these areas, a natural phenomenon, complete cheatgrass stand failure ('die-off'), is apparently caused by a complex interaction among soilborne fungal pathogens. Several Fusarium strains belonging to the Fusarium tricinctum species complex were isolated from these soils and found to be pathogenic on B. tectorum seeds. One of these strains was produced in cheatgrass seed culture to evaluate its ability to produce phytotoxins. Six metabolites were isolated and identified by spectroscopic methods (essentially 1D and 2D NMR and ESIMS) as acuminatopyrone (1), blumenol A (2), chlamydosporol (3), isochlamydosporol (4), ergosterol (5) and 4-hydroxybenzaldehyde (6). Upon testing against B. tectorum in a seedling bioassay, (6) the coleoptile and radicle length of cheatgrass seedlings were significantly reduced. Compounds 1 and 2 showed moderate activity, while 3-5 were not significantly different from the control.
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International Nuclear Information System (INIS)
Blank, R.R.; Young, J.A.
2010-01-01
Invasion of western North America by the annual exotic grass Bromus tectorum L. (cheatgrass) has been an ecological disaster. High soil bioavailability of nitrogen is a contributing factor in the invasive potential of B. tectorum. Application of labile carbon sources to the soil can immobilize soil nitrogen and favor native species. We studied the interaction of labile carbon addition (sucrose), with soil invasion status and fertilizer addition on the growth of B. tectorum. Soils were non invaded (BNI) and B. tectorum invaded (BI). Treatments were control, sucrose, combined fertilizer, and sucrose + fertilizer. The greenhouse experiment continued for 3 growth-cycles. After the 1st growth-cycle, sucrose addition reduced B. tectorum aboveground mass almost 70 times for the BI soil but did not significantly reduce growth in the BNI soil. B. tectorum aboveground mass, after the 1st growth-cycle, was over 27 times greater for BI control soils than BNI control soils. Although sucrose addition reduced soil-solution NO 3 , tissue N was not significantly lowered, suggesting that reduction of soil available N may not be solely responsible for reduction in B. tectorum growth. Non invaded soil inhibits growth of B. tectorum. Understanding this mechanism may lead to viable control strategies.
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West, Amanda M; Kumar, Sunil; Wakie, Tewodros; Brown, Cynthia S; Stohlgren, Thomas J; Laituri, Melinda; Bromberg, Jim
2015-01-01
National Parks are hallmarks of ecosystem preservation in the United States. The introduction of alien invasive plant species threatens protection of these areas. Bromus tectorum L. (commonly called downy brome or cheatgrass), which is found in Rocky Mountain National Park (hereafter, the Park), Colorado, USA, has been implicated in early spring competition with native grasses, decreased soil nitrogen, altered nutrient and hydrologic regimes, and increased fire intensity. We estimated the potential distribution of B. tectorum in the Park based on occurrence records (n = 211), current and future climate, and distance to roads and trails. An ensemble of six future climate scenarios indicated the habitable area of B. tectorum may increase from approximately 5.5% currently to 20.4% of the Park by the year 2050. Using ordination methods we evaluated the climatic space occupied by B. tectorum in the Park and how this space may shift given future climate change. Modeling climate change at a small extent (1,076 km2) and at a fine spatial resolution (90 m) is a novel approach in species distribution modeling, and may provide inference for microclimates not captured in coarse-scale models. Maps from our models serve as high-resolution hypotheses that can be improved over time by land managers to set priorities for surveys and removal of invasive species such as B. tectorum.
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West, Amanda M.; Kumar, Sunil; Wakie, Tewodros; Brown, Cynthia S.; Stohlgren, Thomas J.; Laituri, Melinda; Bromberg, Jim
2015-01-01
National Parks are hallmarks of ecosystem preservation in the United States. The introduction of alien invasive plant species threatens protection of these areas. Bromus tectorum L. (commonly called downy brome or cheatgrass), which is found in Rocky Mountain National Park (hereafter, the Park), Colorado, USA, has been implicated in early spring competition with native grasses, decreased soil nitrogen, altered nutrient and hydrologic regimes, and increased fire intensity. We estimated the potential distribution of B. tectorum in the Park based on occurrence records (n = 211), current and future climate, and distance to roads and trails. An ensemble of six future climate scenarios indicated the habitable area of B. tectorum may increase from approximately 5.5% currently to 20.4% of the Park by the year 2050. Using ordination methods we evaluated the climatic space occupied by B. tectorum in the Park and how this space may shift given future climate change. Modeling climate change at a small extent (1,076 km2) and at a fine spatial resolution (90 m) is a novel approach in species distribution modeling, and may provide inference for microclimates not captured in coarse-scale models. Maps from our models serve as high-resolution hypotheses that can be improved over time by land managers to set priorities for surveys and removal of invasive species such as B. tectorum. PMID:25695255
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Salo, L.F.
2005-01-01
Although invasions by exotic plants have increased dramatically as human travel and commerce have increased, few have been comprehensively described. Understanding the patterns of invasive species spread over space and time will help guide management activities and policy. Tracing the earliest appearances of an exotic plant reveals likely sites of introduction, paving the way for genetic studies to quantify founder events and identify potential source populations. Red brome (Bromus madritensis subsp. rubens) is a Mediterranean winter annual grass that has invaded even relatively undisturbed areas of western North America, where it threatens native plant communities. This study used herbarium records and contemporary published accounts to trace the early introductions and subsequent spread of red brome in western North America. The results challenge the most frequently cited sources describing the early history of this grass and suggest three possible modes for early introductions: the California Gold Rush and Central Valley wheat, southern California shipping, and northern California sheep. Subsequent periods of most rapid spread into new areas, from 1930 to 1942, and of greatest spread into new regions, during the past 50 years, coincide with warm Pacific Decadal Oscillation regimes, which are linked to increased winter precipitation in the southwestern USA and northern Mexico. Global environmental change, including increased atmospheric CO2 levels and N deposition, may be contributing to the success of red brome, relative to native species.
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Directory of Open Access Journals (Sweden)
Amanda M West
Full Text Available National Parks are hallmarks of ecosystem preservation in the United States. The introduction of alien invasive plant species threatens protection of these areas. Bromus tectorum L. (commonly called downy brome or cheatgrass, which is found in Rocky Mountain National Park (hereafter, the Park, Colorado, USA, has been implicated in early spring competition with native grasses, decreased soil nitrogen, altered nutrient and hydrologic regimes, and increased fire intensity. We estimated the potential distribution of B. tectorum in the Park based on occurrence records (n = 211, current and future climate, and distance to roads and trails. An ensemble of six future climate scenarios indicated the habitable area of B. tectorum may increase from approximately 5.5% currently to 20.4% of the Park by the year 2050. Using ordination methods we evaluated the climatic space occupied by B. tectorum in the Park and how this space may shift given future climate change. Modeling climate change at a small extent (1,076 km2 and at a fine spatial resolution (90 m is a novel approach in species distribution modeling, and may provide inference for microclimates not captured in coarse-scale models. Maps from our models serve as high-resolution hypotheses that can be improved over time by land managers to set priorities for surveys and removal of invasive species such as B. tectorum.
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Bio-hydrogen production by dark fermentation from organic wastes and residues
DEFF Research Database (Denmark)
Liu, Dawei
Der er stigende opmærksomhed omkring biohydrogen. Ved hydrogen fermentering kan kun en lille del af det organiske materiale eller COD i affald omdannes til hydrogen. Der findes endnu ingen full-skala bio-hydrogen anlæg, eftersom effektive rentable teknologier ikke er udviklet endnu. En to......-trins proces der kombinerer bio-hydrogen og bio-metan produktionen er en attraktiv mulighed til at øge det totale energi-udbytte af fermentering af organisk materiale. I en to-trins proces, med bio-hydrogen som første trin og bio-methan som andet trin, kunne der opnås 43mL-H2/gVSadded ved 37°C fra...... for en hurtig proces opstart og med højt brint effektivitet. Uden berigelseskulturer fejlede processen, på trods af gentagen genpodning. Optimale procesforhold for brint producerende processer blev bestemt. pH optimum af brintproducerende kulturer var 7.0 og acetat var hæmmende for brintproduktionen...
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Integrated effect of crop sowing date and herbicide stress on fitness of Bromus diandrus Roth
Energy Technology Data Exchange (ETDEWEB)
García, A.L.; Royo-Esnal, A.; Torra, J.; Recasens, J.
2015-07-01
Bromus diandrus Roth is a common weed species that has increased in no-tillage dry-land cereal fields in NE Spain because of the limited control options. The fitness response of plants with different emergence times (ETs) and its influence on demography has huge implications in weed management. With this subject, three ETs (F1, F2 and F3) of B. diandrus were established through three crop-sowing dates (D1, Oct.; D2, Nov.; D3, Dec.) for each of the three years in a barley-wheat-wheat rotation. In barley, the herbicides applied were not specific for B. diandrus, whereas in wheat the specific herbicide mesosulfuron-methyl plus iodosulfuron-methyl-sodium was applied. Plant density after treatments and fitness characteristics were estimated for each weed ET. Weed density decreased for later ETs and fitness was density-dependent, showing significantly higher values when a non-specific herbicide was applied, except in number of caryopses per spikelet. The increasing fitness shown by plants with later ETs and the linear relationships of vegetative biomass vs reproductive biomass and fecundity were disrupted by the herbicide mesosulfuron-methyl plus iodosulfuron-methyl-sodium. Plants that had survived this herbicide when wheat was growing had lower values for all the characteristics analysed. After three seasons, as a consequence of decreasing seed recruitment, a practical depletion of the B. diandrus population was achieved in F2 and F3 (<2.8 and <1 plants/m2, respectively) but not in F1 (60.5 plants/m2). This study shows the importance of delayed crop sowing to optimize the control of B. diandrus in cereal fields with no tillage. (Author)
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Directory of Open Access Journals (Sweden)
Patrick W. Geier
2013-04-01
Full Text Available A study was conducted for three seasons in northwest Kansas, USA to evaluate acetolactate synthase (ALS-inhibiting herbicides for downy brome (Bromus tectorum L. and winter annual broadleaf weed control in winter wheat. Herbicides included pyroxsulam at 18.4 g ai ha−1, propoxycarbazone-Na at 44 g ai ha−1, premixed propoxycarbazone-Na & mesosulfuron-methyl at 27 g ai ha−1, and sulfosulfuron at 35 g ai ha−1. The herbicides were applied postemergence in fall and spring seasons. Averaged over time of application, no herbicide controlled downy brome more than 78% in any year. When downy brome densities were high, control was less than 60%. Pyroxsulam controlled downy brome greater than or similar to other herbicides tested. Flixweed (Descurainia sophia L., blue mustard [Chorispora tenella (Pallas DC.], and henbit (Lamium amplexicaule L. control did not differ among herbicide treatments. All herbicides tested controlled flixweed and blue mustard at least 87% and 94%, respectively. However, none of the herbicides controlled henbit more than 73%. Fall herbicide applications improved weed control compared to early spring applications; improvement ranged from 3% to 31% depending on the weed species. Henbit control was greatly decreased by delaying herbicide applications until spring compared to fall applications (49% vs. 80% control. Herbicide injury was observed in only two instances. The injury was ≤13% with no difference between herbicides and the injury did not impact final plant height or grain yield.
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DEFF Research Database (Denmark)
2016-01-01
Valg af materiale/medie/form: Video med person og skærm til MOOC for elever Valg af arbejdsform: Mundtlig og visuel præsentation af analysemodel trin for trin - som opsamling på enkeltelementer præsenteret i resten af MOOC'et Begrundelse for valg af materiale/medie/form/arbejdsform: Forsøg på at ...
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Soil nitrogen mineralization not affected by grass species traits
Maged Ikram Nosshi; Jack Butler; M. J. Trlica
2007-01-01
Species N use traits was evaluated as a mechanism whereby Bromus inermis (Bromus), an established invasive, might alter soil N supply in a Northern mixed-grass prairie. We compared soils under stands of Bromus with those from three representative native grasses of different litter C/N: Andropogon...
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Lineær programmering med Excel
DEFF Research Database (Denmark)
Lynggaard, Peter
Publikationen giver en introduktion til faget "Lineær programmering". Formulering og løsning bygger på, at modellerne opstilles og løses i et Excel-regneark. Fremgangsmåden er forklaret trin for trin, således at hæftet kan bruges som selvstudiemateriale. Indholdsfortegnelse Generelt om styring og...... planlægning Lineær programmering Excel solveren Fortolkning af udskrifter Degeneration Excel tips Opgaver med løsninger...
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Taxonomy and leaf anatomy of the genus Ehrharta (Poaceae) in southern Africa: the Dura group
G. E. Gibbs Russel; R. P. Ellis
1988-01-01
The Dura species group in the genus Ehrharta Thunb. is differentiated morphologically by the perennial habit and the very large, awned, subglabrous spikelets and anatomically by the occurrence of tanniniferous cells and wax platelets obscuring the stomatal pores. The Dura group consists of two species, E. dura Nees ex Trin. and E. microlaena Nees ex Trin., which occur only in Mountain Fynbos. The group shows no clear morphological or anatomical relationship with other species groups in the ge...
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Schaeffer, Sean M.; Ziegler, Susan E.; Belnap, Jayne; Evans, R.D.
2012-01-01
Soil nitrogen (N) is an important component in maintaining ecosystem stability, and the introduction of non-native plants can alter N cycling by changing litter quality and quantity, nutrient uptake patterns, and soil food webs. Our goal was to determine the effects of Bromus tectorum (C3) invasion on soil microbial N cycling in adjacent non-invaded and invaded C3 and C4 native arid grasslands. We monitored resin-extractable N, plant and soil δ13C and δ15N, gross rates of inorganic N mineralization and consumption, and the quantity and isotopic composition of microbial phospholipid biomarkers. In invaded C3 communities, labile soil organic N and gross and net rates of soil N transformations increased, indicating an increase in overall microbial N cycling. In invaded C4 communities labile soil N stayed constant, but gross N flux rates increased. The δ13C of phospholipid biomarkers in invaded C4 communities showed that some portion of the soil bacterial population preferentially decomposed invader C3-derived litter over that from the native C4 species. Invasion in C4 grasslands also significantly decreased the proportion of fungal to bacterial phospholipid biomarkers. Different processes are occurring in response to B. tectorum invasion in each of these two native grasslands that: 1) alter the size of soil N pools, and/or 2) the activity of the microbial community. Both processes provide mechanisms for altering long-term N dynamics in these ecosystems and highlight how multiple mechanisms can lead to similar effects on ecosystem function, which may be important for the construction of future biogeochemical process models.
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Taxonomy and leaf anatomy of the genus Ehrharta (Poaceae in southern Africa: the Dura group
Directory of Open Access Journals (Sweden)
G. E. Gibbs Russel
1988-10-01
Full Text Available The Dura species group in the genus Ehrharta Thunb. is differentiated morphologically by the perennial habit and the very large, awned, subglabrous spikelets and anatomically by the occurrence of tanniniferous cells and wax platelets obscuring the stomatal pores. The Dura group consists of two species, E. dura Nees ex Trin. and E. microlaena Nees ex Trin., which occur only in Mountain Fynbos. The group shows no clear morphological or anatomical relationship with other species groups in the genus in southern Africa.
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Bromberg, J.E.; Kumar, S.; Brown, C.S.; Stohlgren, T.J.
2011-01-01
Downy brome (Bromus tectorum L.), an invasive winter annual grass, may be increasing in extent and abundance at high elevations in the western United States. This would pose a great threat to high-elevation plant communities and resources. However, data to track this species in high-elevation environments are limited. To address changes in the distribution and abundance of downy brome and the factors most associated with its occurrence, we used field sampling and statistical methods, and niche modeling. In 2007, we resampled plots from two vegetation surveys in Rocky Mountain National Park for presence and cover of downy brome. One survey was established in 1993 and had been resampled in 1999. The other survey was established in 1996 and had not been resampled until our study. Although not all comparisons between years demonstrated significant changes in downy brome abundance, its mean cover increased nearly fivefold from 1993 (0.7%) to 2007 (3.6%) in one of the two vegetation surveys (P = 0.06). Although the average cover of downy brome within the second survey appeared to be increasing from 1996 to 2007, this slight change from 0.5% to 1.2% was not statistically significant (P = 0.24). Downy brome was present in 50% more plots in 1999 than in 1993 (P = 0.02) in the first survey. In the second survey, downy brome was present in 30% more plots in 2007 than in 1996 (P = 0.08). Maxent, a species-environmental matching model, was generally able to predict occurrences of downy brome, as new locations were in the ranges predicted by earlier generated models. The model found that distance to roads, elevation, and vegetation community influenced the predictions most. The strong response of downy brome to interannual environmental variability makes detecting change challenging, especially with small sample sizes. However, our results suggest that the area in which downy brome occurs is likely increasing in Rocky Mountain National Park through increased frequency and cover
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4 trin til succesfuld samskabelse
DEFF Research Database (Denmark)
Hald Larsen, Stine
2014-01-01
Samskabelsesprojekter mellem offentlige, frivillige og private organisationer er en vigtig kilde til innovation. Som leder af samskabelse skal du tage initiativ til og facilitere forhandlingsprocesser, så alle parter får noget ud af samarbejdet. Læs her, hvordan du leder en forhandlingsproces i f...
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DEFF Research Database (Denmark)
Jensen, Lone
2006-01-01
En Creative Commons licens giver en forfatter mulighed for at udbyde sit værk i en alternativ licensløsning, som befinder sig på forskellige trin på en skala mellem yderpunkterne "All rights reserved" og "No rights reserved". Derved opnås licensen "Some rights reserved"......En Creative Commons licens giver en forfatter mulighed for at udbyde sit værk i en alternativ licensløsning, som befinder sig på forskellige trin på en skala mellem yderpunkterne "All rights reserved" og "No rights reserved". Derved opnås licensen "Some rights reserved"...
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National Research Council Canada - National Science Library
Belnap, Jayne; Evans, R. D; Phillips, Susan L; Reheis, Merith; Reynolds, Rich; Sanford, Robert; Webb, Bruce
2004-01-01
Bromus tectorum (hereafter referred to as Bromus) is a non-native annual grass from the Mediterranean region that arrived in the United States in the late 19th century and soon spread throughout the western states...
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Condon, Lea A.; Pyke, David A.
2018-01-01
Shrubs, bunchgrasses and biological soil crusts (biocrusts) are believed to contribute to site resistance to plant invasions in the presence of cattle grazing. Although fire is a concomitant disturbance with grazing, little is known regarding their combined impacts on invasion resistance. We are the first to date to test the idea that biotic communities mediate the effects of disturbance on site resistance. We assessed cover of Bromus tectorum, shrubs, native bunchgrasses, lichens and mosses in 99 burned and unburned plots located on similar soils where fires occurred between 12 and 23 years before sampling. Structural equation modeling was used to test hypothesized relationships between environmental and disturbance characteristics, the biotic community and resistance to B. tectorum cover. Characteristics of fire and grazing did not directly relate to cover of B. tectorum. Relationships were mediated through shrub, bunchgrass and biocrust communities. Increased site resistance following fire was associated with higher bunchgrass cover and recovery of bunchgrasses and mosses with time since fire. Evidence of grazing was more pronounced on burned sites and was positively correlated with the cover of B. tectorum, indicating an interaction between fire and grazing that decreases site resistance. Lichen cover showed a weak, negative relationship with cover of B. tectorum. Fire reduced near-term site resistance to B. tectorum on actively grazed rangelands. Independent of fire, grazing impacts resulted in reduced site resistance to B. tectorum, suggesting that grazing management that enhances plant and biocrust communities will also enhance site resistance.
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Directory of Open Access Journals (Sweden)
Zeinab Alipoor
2015-04-01
Full Text Available This study was conducted in two factorial experiment based on completely randomized design with three replications at research laboratory of faculty of agriculture in University of Birjand in 2013. Factors included saffron organs at 2 levels (leaves and corms and water extract concentrations at 5 levels (0, 0.5, 1, 1.5 and 2 percent.The allelopathic effects of saffron leaves and corms on seed germination and seedling growth characteristics of flixweed (Descurainia sophia L. and downy brome (Bromus tectorum L. were studied in two separate experiments. Results indicated lowest seed germination percentage of downy brome and flixweed were observed at concentration of 2% of corm extract (by 65% and 66% reduce compared to control, respectively. The rate of germination of downy brome decreased (by 71% compared to control with concentration of 2% of leaf extract but the rate of germination on flixweed was not significantly affected by extract concentrations. Different concentrations of leaf and corm extracts significantly decreased length and weight of plumule and radicals of two weeds. A logistic model provided a successful estimation of relationship between leaf water extract and germination percentage of two weeds. Based on orthogonal comparison tests, the allelopathic inhibition effects of saffron leaves and corms were more on downy brome and flixweed, respectively.
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Directory of Open Access Journals (Sweden)
Henryk Skrabka
2015-06-01
Full Text Available The contents of protein, amino acids, reducing sugars, fibre (ADF, lignin (ADL and mineral components in tissues of smooth brome grass – Bromus inermis and rescue grass – Bromus unioloides were determined. The purpose of this investigation was to compare the nutritive value of either species of grass.
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Cheatgrass and red brome; the history and biology of two invaders
Chad R. Reid; Sherel Goodrich; James E. Bowns
2008-01-01
In recent history, there has not been a more ecologically important event than the introduction of cheatgrass (Bromus tectorum) and red brome (Bromus rubens) into the Intermountain West. These grasses are very similar in ecology and history and are separated mostly by function of elevation. Both species are from the Mediterranean...
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Pyrenophoric acids B and C, two new phytotoxic sesquiterpenoids produced by Pyrenophora semeniperda
Marco Masi; Susan Meyer; Alessio Cimmino; Suzette Clement; Beth Black; Antonio Evidente
2014-01-01
Two new phytotoxic sesquiterpenoid acids, named pyrenophoric acids B and C, were isolated together with the related pyrenophoric and abscisic acids from solid Bromus tectorum (cheatgrass) seed culture of the seed pathogen Pyrenophora semeniperda. This fungus has been proposed as a mycoherbicide for biocontrol of cheatgrass (Bromus tectorum), a Eurasian annual grass...
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DEFF Research Database (Denmark)
Mortensen, Thomas Bøtker
2009-01-01
Facebook Marketing – Leverage Social Media to Grow Your Business af Steven Holzner er Facebook Marketing fra A-Z, som kan anbefales til virksomheder, som overvejer at bevæge sig ud i cyber space og afprøve mulighederne for at markedsføre sig dér. Bogen beskriver på hvilke væsentlige punkter...... marketing på Facebook adskiller sig fra traditionel marketing, og gennemgår trin for trin de fundamentale ting, som man skal vide for, at virksomheden kan agere med den tilsigtede effekt i et socialt netværk som Facebook. Og eftersom 34 % af den danske befolkning i dag er hoppet med på Facebook vognen og...... har oprettet en profil på Facebook, er potentialet åbenlyst....
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Directory of Open Access Journals (Sweden)
Instituto de Investigación en Ciencia Animal y Tecnología (IICAT
2016-04-01
Full Text Available This research was conducted in the municipality of Santiago de Machaca is the first section of the province José Manuel Pando, is located southeast of the department of La Paz, a distance of 205 km, from the city of La Paz, the research objectives were to determine the consumption Flames selected a native pasture and determine the nutritional quality selected (% PC, % NDF,% FDA Burning of native pasture. The results were: 18 native grasses consumed by the four camels, fodder were identified that more quantity than was consumed Trifolium pratensis (layu layu No.1 consumed camel, camel No. 2 (473 (462.93 gr. , 6 g, camel No. 3 (544.43 g and the camel No. 4 (477.87 g, native grassland and Bromus catharticus (Cebadilla camélido No.1 consumed (357.12 gr., camel No. 2 (409,6gr., camel No. 3 (445,44gr. and camel No. 4 ( 310,61gr.. The total consumption of 18 forage species based on live weight (Kg. was next, camel No.1 consumed (1,323 Kg. (62 Kg. PV, camel No. 2 (1,280Kg. (60 Kg. PV, camel No. 3 (1,237Kg. (58 Kg. PV and camel No. 4 (1,195 Kg. (56 Kg. PV. The statistical analysis of the four camels, by completely randomized design (ANOVA, is indicating no significant difference (p ≥0.05 with respect to consumption of native grasslands. The samples sent to the laboratory of the Institute of Diagnostic Laboratory Services and Health Research Institute SELADIS were: maximum concentration crude protein found in the pasture Trifolium pratensis (layu layu 15.93% and is lower Bromus grassland catharticus (Cebadilla 15.33%; The concentration of neutral detergent fiber (NDF, Bromus grassland catharticus (Cebadilla has 65.66% and the pasture Trifolium pratensis (layu layu 45.21%, the concentration is directly related to the type of pasture and composition flora, being the Bromus grassland catharticus (Cebadilla is enhanced by the structure of cell walls. Grasslands who consume more camels on the geographic location and area of study is the Trifolium
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Keren, Ilai N.; Menalled, Fabian D.; Weaver, David K.; Robison-Cox, James F.
2015-01-01
Worldwide, the landscape homogeneity of extensive monocultures that characterizes conventional agriculture has resulted in the development of specialized and interacting multitrophic pest complexes. While integrated pest management emphasizes the need to consider the ecological context where multiple species coexist, management recommendations are often based on single-species tactics. This approach may not provide satisfactory solutions when confronted with the complex interactions occurring between organisms at the same or different trophic levels. Replacement of the single-species management model with more sophisticated, multi-species programs requires an understanding of the direct and indirect interactions occurring between the crop and all categories of pests. We evaluated a modeling framework to make multi-pest management decisions taking into account direct and indirect interactions among species belonging to different trophic levels. We adopted a Bayesian decision theory approach in combination with path analysis to evaluate interactions between Bromus tectorum (downy brome, cheatgrass) and Cephus cinctus (wheat stem sawfly) in wheat (Triticum aestivum) systems. We assessed their joint responses to weed management tactics, seeding rates, and cultivar tolerance to insect stem boring or competition. Our results indicated that C. cinctus oviposition behavior varied as a function of B. tectorum pressure. Crop responses were more readily explained by the joint effects of management tactics on both categories of pests and their interactions than just by the direct impact of any particular management scheme on yield. In accordance, a C. cinctus tolerant variety should be planted at a low seeding rate under high insect pressure. However as B. tectorum levels increase, the C. cinctus tolerant variety should be replaced by a competitive and drought tolerant cultivar at high seeding rates despite C. cinctus infestation. This study exemplifies the necessity of
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Directory of Open Access Journals (Sweden)
Bouhaouel, I.
2016-01-01
Full Text Available Description of the subject. The present study focuses on the description of the allelopathic interactions between wild and crop species that may occur in a given ecosystem. Objectives. The objective is the evaluation of the allo- and autoinhibition activity of root exudates of barley (Hordeum vulgare L. subsp. vulgare and great brome (Bromus diandrus Roth. seedlings by water-soluble allelochemicals. Method. The allelopathic activities of five Tunisian barley genotypes (modern varieties and landraces, one Saudi Arabian barley landrace and great brome were assessed using a modified laboratory bioassay named "seedling-after-seedling agar method". Results. The barley or the great brome reduced, to a greater extent, the root growth compared to the shoot growth of receiver species. The response of the root system architecture of the great brome towards barley root exudates was studied in detail. All the measured root traits were highly sensitive to the presence of barley. In our conditions, the allelopathic activity of barley root exudates had no apparent relationship with the size of the root and a prominent action of genetic determinants in the allelopathic potential between genotypes is proposed. The alloinhibitory activity of barley or great brome root exudates deferred between the receiver species but was always higher than the autoinhibition potential. The autoinhibition in barley proved to depend on whether the genotypes used as donor and receiver are identical or different, suggesting a specific interaction of allelochemicals with the receiver plant. These molecules seem to be the main actors in the allelopathic barley potential as external factors such variations of pH have no evident relevance in the inhibition process. Conclusions. Barley and great brome exude molecules in their surroundings. This affects the growth of the receiver plants, suggesting that these compounds might contribute to the plant community dynamics.
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Keren, Ilai N; Menalled, Fabian D; Weaver, David K; Robison-Cox, James F
2015-01-01
Worldwide, the landscape homogeneity of extensive monocultures that characterizes conventional agriculture has resulted in the development of specialized and interacting multitrophic pest complexes. While integrated pest management emphasizes the need to consider the ecological context where multiple species coexist, management recommendations are often based on single-species tactics. This approach may not provide satisfactory solutions when confronted with the complex interactions occurring between organisms at the same or different trophic levels. Replacement of the single-species management model with more sophisticated, multi-species programs requires an understanding of the direct and indirect interactions occurring between the crop and all categories of pests. We evaluated a modeling framework to make multi-pest management decisions taking into account direct and indirect interactions among species belonging to different trophic levels. We adopted a Bayesian decision theory approach in combination with path analysis to evaluate interactions between Bromus tectorum (downy brome, cheatgrass) and Cephus cinctus (wheat stem sawfly) in wheat (Triticum aestivum) systems. We assessed their joint responses to weed management tactics, seeding rates, and cultivar tolerance to insect stem boring or competition. Our results indicated that C. cinctus oviposition behavior varied as a function of B. tectorum pressure. Crop responses were more readily explained by the joint effects of management tactics on both categories of pests and their interactions than just by the direct impact of any particular management scheme on yield. In accordance, a C. cinctus tolerant variety should be planted at a low seeding rate under high insect pressure. However as B. tectorum levels increase, the C. cinctus tolerant variety should be replaced by a competitive and drought tolerant cultivar at high seeding rates despite C. cinctus infestation. This study exemplifies the necessity of
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Directory of Open Access Journals (Sweden)
Ilai N Keren
Full Text Available Worldwide, the landscape homogeneity of extensive monocultures that characterizes conventional agriculture has resulted in the development of specialized and interacting multitrophic pest complexes. While integrated pest management emphasizes the need to consider the ecological context where multiple species coexist, management recommendations are often based on single-species tactics. This approach may not provide satisfactory solutions when confronted with the complex interactions occurring between organisms at the same or different trophic levels. Replacement of the single-species management model with more sophisticated, multi-species programs requires an understanding of the direct and indirect interactions occurring between the crop and all categories of pests. We evaluated a modeling framework to make multi-pest management decisions taking into account direct and indirect interactions among species belonging to different trophic levels. We adopted a Bayesian decision theory approach in combination with path analysis to evaluate interactions between Bromus tectorum (downy brome, cheatgrass and Cephus cinctus (wheat stem sawfly in wheat (Triticum aestivum systems. We assessed their joint responses to weed management tactics, seeding rates, and cultivar tolerance to insect stem boring or competition. Our results indicated that C. cinctus oviposition behavior varied as a function of B. tectorum pressure. Crop responses were more readily explained by the joint effects of management tactics on both categories of pests and their interactions than just by the direct impact of any particular management scheme on yield. In accordance, a C. cinctus tolerant variety should be planted at a low seeding rate under high insect pressure. However as B. tectorum levels increase, the C. cinctus tolerant variety should be replaced by a competitive and drought tolerant cultivar at high seeding rates despite C. cinctus infestation. This study exemplifies the
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A poststructuralistic approach to learning processes in adult education
DEFF Research Database (Denmark)
Jensen, Anne Winther
Konferencepaper: Med en poststrukturalistisk tilgang, fokuserer paperet i en case-analyse på, hvordan der er forskellige diskurser, der dominerer på forskellige niveauer på en konkret Sosu-skole (Social- og sundhedsuddannelserne, trin 1). Analysen peger på, at forskellige elevgrupper positioneres...
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2068-IJBCS-Article-Saidou Ousseina
African Journals Online (AJOL)
hp
que Schoenefeldia gracilis Kunth., Aristida mutabilis Trin. et Rupr., Dactyloctenium aegyptiaca (L.) Willd., Tribulus terrestris L. (Ousseina, 2012) parsemée de plantes ligneuses (Maerua crassifolia. Forsk.,. Balanites aegyptiaca (L.) Del., Acacia senegal (L.) Willd., Acacia tortilis (Forssk.) Hayne subsp. raddiana (Savi) Brenan,.
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Zhang, Fang; Xiong, Hei-gang; Nurbay, Abdusalih; Luan, Fu-ming
2011-12-01
Based on the field-measured Vis-NIR reflectance of four common types of halophyte (Achnatherum splendens(Trin.) Nevski, Sophora alopecuroides L., Camphorosma monspeliaca L. subsp. lessingii(L.)Aellen, Alhagi sparsifolia shap) within given spots in the Northern Slope Area of Tianshan Mountain in Xinjiang, the spectral response characteristics and species recognition of these types of halophyte were analyzed. The results showed that (Alhagi sparsifolia shap) had higher chlorophyll and carotenoid by CARI and SIPI index. (Sophora alopecuroides L. was at a vigorously growing state and had a higher NDVI compared with the other three types of halophyte because of its greater canopy density. But its CARI and SIPI values were lower due to the influence of its flowers. (Sophora alopecuroides L.) and (Camphorosma monspeliaca L. subsp. lessingii(L.)) had stable REPs and BEPs, but REPs and BEPs of (Achnatherum splendens(Trin.)Nevski, Aellen, Alhagi sparsifolia shap) whose spectra red shift and spectra blue shift occurred concurrently obviously changed. There was little difference in spectral curves among the four types of halophyte, so the spectrum mixing phenomenon was severe. (Camphorosma monspeliaca L. subsp. lessingii (L.)Aellen) and (Alhagi sparsifolia shap) could not be separated exactly in a usual R/NIR feature space in remote sensing. Using the stepwise discriminant analysis, five indices were selected to establish the discriminant model, and the model accuracy was discussed using the validated sample group. The total accuracy of the discriminant model was above 92% and (Achnatherum splendens(Trin.)Nevski) and (Camphorosma monspeliaca L. subsp. lessingii(L.)Aellen) could be respectively recognized 100% correctly.
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Multi-Polarization ASAR Backscattering from Herbaceous Wetlands in Poyang Lake Region, China
Directory of Open Access Journals (Sweden)
Huiyong Sang
2014-05-01
Full Text Available Wetlands are one of the most important ecosystems on Earth. There is an urgent need to quantify the biophysical parameters (e.g., plant height, aboveground biomass and map total remaining areas of wetlands in order to evaluate the ecological status of wetlands. In this study, Environmental Satellite/Advanced Synthetic Aperture Radar (ENVISAT/ASAR dual-polarization C-band data acquired in 2005 is tested to investigate radar backscattering mechanisms with the variation of hydrological conditions during the growing cycle of two types of herbaceous wetland species, which colonize lake borders with different elevation in Poyang Lake region, China. Phragmites communis (L. Trin. is semi-aquatic emergent vegetation with vertical stem and blade-like leaves, and the emergent Carex spp. has rhizome and long leaves. In this study, the potential of ASAR data in HH-, HV-, and VV-polarization in mapping different wetland types is examined, by observing their dynamic variations throughout the whole flooding cycle. The sensitivity of ASAR backscattering coefficients to vegetation parameters of plant height, fresh and dry biomass, and vegetation water content is also analyzed for Phragmites communis (L. Trin. and Carex spp. The research for Phragmites communis (L. Trin. shows that HH polarization is more sensitive to plant height and dry biomass than HV polarization. ASAR backscattering coefficients are relatively less sensitive to fresh biomass, especially in HV polarization. However, both are highly dependent on canopy water content. In contrast, the dependence of HH- and HV- backscattering from Carex community on vegetation parameters is poor, and the radar backscattering mechanism is controlled by ground water level.
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Indian Academy of Sciences (India)
2013-12-27
Dec 27, 2013 ... on the basis of multi-wavelength properties of X-ray sources and their ... 1. In trin sic colors are estim ated fro m observed colors corrected fo .... 869#111 in the CHANDRA X-ray source catalogue, and found two sources within.
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Clevering, O.A.
1999-01-01
In many European countries a strong decline of Phragmites australis (Cav.) Trin. Ex Steudel (common reed) has been observed. In some instances this decline has been related to the accumulation of litter. A greenhouse experiment was conducted with P. australis cuttings from different stable and
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DEFF Research Database (Denmark)
Schjerup Hansen, J.; Hansen, K.E.; Kristensen, H.
Statens Byggeforskningsinstitut har i foråret 1996 for Miljø- og Energiministeriets landsplanafdeling evalueret eksempelprojekterne fra Landsplanredegørelsen 1992. I alt 11 eksempelprojekter blev iværksat 14 forskellige steder i landet i 1993/94, og det er forløbet og resultaterne af disse projek...
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Belnap, J.; Sherrod, S.K.
2009-01-01
Greenhouse experiments were undertaken to identify soil factors that curtail growth of the exotic annual grass Bromus tectorum L. (cheatgrass) without significantly inhibiting growth of native perennial grasses (here represented by Hilaria jamesii [Torr.] Benth). We grew B. tectorum and H. jamesii alone (monoculture pots) and together (combination pots) in soil treatments that manipulated levels of soil phosphorus, potassium, and sodium. Hilaria jamesii showed no decline when its aboveground biomass in any of the applied treatments was compared to the control in either the monoculture or combination pots. Monoculture pots of B. tectorum showed a decline in aboveground biomass with the addition of Na2HPO4 and K2HPO4. Interestingly, in pots where H. jamesii was present, the negative effect of these treatments was ameliorated. Whereas the presence of B. tectorum generally decreased the aboveground biomass of H. jamesii (comparing aboveground biomass in monoculture versus combination pots), the presence of H. jamesii resulted in an enhancement of B. tectorum aboveground biomass by up to 900%. We hypothesize that B. tectorum was able to obtain resources from H. jamesii, an action that benefited B. tectorum while generally harming H. jamesii. Possible ways resources may be gained by B. tectorum from native perennial grasses include (1) B. tectorum is protected from salt stress by native plants or associated soil biota; (2) when B. tectorum is grown with H. jamesii, the native soil biota is altered in a way that favors B. tectorum growth, including B. tectorum tapping into the mycorrhizal network of native plants and obtaining resources from them; (3) B. tectorum can take advantage of root exudates from native plants, including water and nutrients released by natives via hydraulic redistribution; and (4) B. tectorum is able to utilize some combination of the above mechanisms. In summary, land managers may find adding soil treatments can temporarily suppress B. tectorum
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Det indskrevne publikum i politiske kommentarer
DEFF Research Database (Denmark)
Bengtsson, Mette
2016-01-01
I denne artikel fremsættes en kritik af kommentargenren i en dansk kontekst. Med udgangspunkt i 90 kommentarartikler fra landsdækkende aviser under folketingsvalget i 2011 laves en analyse af genrens indskrevne publikum efter Edwin Blacks analyseforskrifter i tre trin: Først analyseres materialet...
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DEFF Research Database (Denmark)
Nielsen, Lene
Mennesker forholder sig helst til andre mennesker, ikke til groft forenklede typer eller segmenter. Så enkel er sandheden bag Persona, en brugerfokuseret designmetode, som nu breder sig fra interaktion i it til andre områder. Aktører i fremtidens udviklingsprojekter må tidligt kunne se modtagerne...... af deres produkter for sig, hvad enten det drejer sig om en internetportal eller en møbelfabrik. Udviklere må kunne beskrive nye brugere in persona, i et livagtigt design, som om de med deres forskellige holdninger, ønsker og vaner allerede var godt i gang med at føre et produkts muligheder ud i...... forskningsprojekt og fem års erfaring med at løse opgaver for erhvervslivet gør Danmarks førende ekspert i persona nu sin egen tilgang til metoden praktisk tilgængelig. Udviklere af it, kommunikationsløsninger og innovative produkter af enhver art inviteres til at studere processen trin for trin....
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Van der Putten, W.H.
1997-01-01
Reed (Phragmites australis (Cav.) Trin. ex Steudel) is one of the dominant plant species in European land-water ecotones. During the past decades reed belts have died back, especially in central and eastern Europe. The aim of the European Research Programme on Reed Die-back and Progression (EUREED),
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Ketterer, Holly L.; Han, Kyunghee; Hur, Jaehong; Moon, Kyungjoo
2010-01-01
In response to the concern that Minnesota Multiphasic Personality Inventory-2 (MMPI-2; J. N. Butcher, W. Dahlstrom, J. R. Graham, A. Tellegen, & B. Kaemmer, 1989; J. N. Butcher et al., 2001) Variable Response Inconsistency (VRIN) and True Response Inconsistency (TRIN) score invalidity criteria recommended for use with American samples results…
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Het geslacht Chloris in Nederland
Ooststroom, van S.J.; Reichgelt, Th.J.
1962-01-01
The genus Chloris Sw. is represented in the Netherlands by 4 adventitious species, viz. C. virgata Sw., C. truncata R. Br., C. divaricata R. Br., and C. pycnothrix Trin. Descriptions of these species and figures of their florets are given. The four species may be distinguished with the aid of the
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Energy Technology Data Exchange (ETDEWEB)
Antonova, Elena V.; Pozolotna, Vera N. [Institute of Plant and Animal Ecology UB RAS, 8 Marta str. 202, 620144, Ekaterinburg (Russian Federation); Karimullina, Elina M. [Institute of Plant and Animal Ecology UB RAS, 8 Marta str. 202, 620144, Ekaterinburg (Russian Federation); Department of Developmental and Cell Biology, University of California, 2011 Biological Sciences III, Irvine, CA 92697-2300 (United States); Roeder, Marion S. [Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstrasse 3, D-06466, Gatersleben (Germany)
2014-07-01
This investigation dedicates the problem of remote consequences of radiation impact on plant populations. This is a part of a complex research, which includes the classic triad of radioecology (Timofeev-Ressovsky 1963): 'accumulation and migration of radionuclides in different components of ecosystems - assessment of radiation dose - investigation of radiobiological effects'. We used the populations of smooth brome (Bromus inermis Leyss.) as a model system for the investigation of radiobiological and genetic effects. It is radiosensitive plant (Preobrazhenskaya 1971). These species may be used as objects for bio-indication at the radioactive contaminated areas, and as well as large-scale radioecological studies, because the adaptation processes are faster for radiosensitive species (Shevchenko et al., 1992; Pozolotina et al. 2005). We calculated external and internal whole-body dose rates by ERICA Tool (Karimullina et al., 2013). The total dose rate for brome was under 100 mGy h{sup -1} at the most polluted site but 43-110 times (Tier 3) exceeded the background along the pollution gradient. Therefore it can be concluded that herbaceous plant populations currently exist under low level chronic exposure at the EURT area. During seven years we have studied variability of viability, mutability and radioresistance of brome seed progeny. The combined effects of radiation exposure and weather conductions at the EURT area were absent. It may be connect with wide variability of inter-population test parameters. At the same time the weather conductions had an influence on the quality of seed progeny at the background area. We analyzed also correlation between original viability and radioresistance of seed progeny from the all plots. This dependence was positive. It was shown negative dependence between original viability of seed progeny and low weight molecular antioxidants content too. Ionizing radiation is a mutagenic factor and, accordingly, elevated mutation
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DEFF Research Database (Denmark)
Flyvbjerg, Bent
optimisme og misinformation. RCF bygger på teorier, som vandt Daniel Kahneman Nobelprisen i økonomi i 2002. RCF estimerer budgettet for et givet projekt på grundlag af de faktiske udfald for budgetterne i en reference-klasse af projekter. RCF udføres i tre trin: 1. Identifikation af en relevant reference...
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Symposium on Command and Control Research (1988) Held in Monterey, California on Jun 7-9, 1988
1988-09-30
ELa -1cl~ca aya Display: Show-Icon Show-Overlay-icons Erase-icon Eras e.Overlay-icons Highlight: Highlight-Icon Highlight-Overlay-icons Dehighlight...poanrtiso duty hosirs, for the esastesov 5: ’Referencescomptia. Peacetinme diary hos; are trin lsoors a day’,r days ank.Note that thiscanoles os6sio4- to heo
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Microsporogenesis, reproductive behavior, and fertility in five Pennisetum species
Energy Technology Data Exchange (ETDEWEB)
Dujardin, M.; Hanna, W.
1984-01-01
Microsporogenesis, reproductive behavior, pollen fertility and seed set were studied in Pennisetum basedowii Summerhayes and C. E. Hubbard, 2n=54; P. macrostachyum (Brough.) Trin., 2n=54; P. macrourum Trin., 2n=36; P. polystachion (L.) Schult, 2n=54; and P. squamulatum Fresen 2n=54. Meiosis was regular in P. basedowii with primarily bivalent pairing. As many as 54 univalents were observed at metaphase I in P. macrostachyum. A high frequency of univalents at metaphase I in P. macrourum resulted in lagging chromosomes and micronuclei at anaphase I and telophase I, respectively. Pennisetum polystachion and P. squamulatum showed frequent multivalent chromosome associations. Studies of megasporogenesis and embryo sac development in P. basedowii showed sexual reproduction. Pennisetum macrostachyum was highly male sterile with predominantly aposporous apomictic embryo sac development. Pennisetum macrourum, P. polystachion, and P. squamulatum had only aposporous embryo sac development. Pennisetum macrourum, P. polystachion, and P. squamulatum had only aposporous embryo sac development. Seed propagated progenies of these latter three species were uniform and matromorphic, confirming the obligate apomixis nature.
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LAS ESPECIES DE MUHLENBERGIA (POACEAE: CHLORIDOIDEAE DE ARGENTINA
Directory of Open Access Journals (Sweden)
Peterson Paul
2011-06-01
Full Text Available Se presenta un estudio taxonómico de las especies nativas argentinas del géneroMuhlenbergia, basado en el análisis de los especímenes depositados en 48 herbarios.Se analizan diversos aspectos relativos a la clasifi cación, la nomenclatura y lavariación morfológica de los caracteres. Muhlenbergia está representado enArgentina por 18 especies nativas. Se proporcionan claves para reconocer lasespecies presentes en el país, así como también descripciones de éstas, sinónimos,ilustraciones, distribución geográfica y algunos comentarios morfológicos yecológicos. Muhlenbergia breviaristata (Hack. Parodi y Muhlenbergia holwayorumHitchc., se reducen como sinónimos del híbrido Muhlenbergia angustata (J. PreslKunth × M. rigida (Kunth Kunth. Muhlenbergia diversiglumis Trin. se cita porprimera vez para la Argentina. Por otra parte, las especies Muhlenbergia tenella(Kunth Trin. y Muhlenbergia tenuissima (J. Presl Kunth se excluyen de la fl orade Argentina.
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Rektorers forståelse av mobbing i skolen
DEFF Research Database (Denmark)
Hansen, Helle Rabøl
2008-01-01
PÅ opfordring fra redaktionen gives en kommentar med dansk vinkel til den norske artikel 'Rektorers forståelse av mobbning i skolen'.Den omtalte artikel er at betragte som første trin i indførelse af en nordisk mobbeforståelse med undgangspunkt i Dan Olweus begrebsafgrænsning.Der savnes også en i...
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Kolm näitust, neli kunstnikku, sada õit / Tanel Veenre
Veenre, Tanel, 1977-
2011-01-01
Imbi Ploompuu keraamika ja graafika näitus Eesti Tarbekunsti- ja Disainimuuseumis 4. sept.-ni. Kätrin Beljajevi ja Pilleriin Jürisoo ehtenäitus "Herbaarium" Tallinnas Iida galeriis 31. aug.-ni. Maiu Moosese ehtenäitus "Tänu" Tallinnas Hop-galeriis 19. juulini 2011. Linnainstallatsioonide festivali tööst "Audiotuur", autor arhitekt Kadri Klementi
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Offentliggørelse af kursrelevante oplysninger
DEFF Research Database (Denmark)
Werlauff, Erik; Schaumburg-Müller, Peer
2013-01-01
Artiklen analyserer, særligt på baggrund af EU-Domstolens dom af 28. juni 2012 i C-19/11, Daimler AG, hvilken betydning en række mellemliggende trin, der fører frem til en kursrelevant og offentliggørelsespligtig begivenhed, har for tidspunktet for indtrædelsen af pligten til offentliggørelse. De...
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Plasmafysik og fusionsenergi - fremtidens energikilde
DEFF Research Database (Denmark)
Dam Heiselberg, Bodil; Heiselberg, Henning
Fusionsreaktoren ITER bygges i disse år i Frankrig af EU, Kina, Japan, Rusland, Indien, Sydkorea og USA og afløser JET i England. ITER er nok sidste trin i forskningsfusionsreaktorer. ITER forventes at kunne producere mere energi, end der bruges til at køre den, og vil dermed være den første...
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Provencher, Louis; Frid, Leonardo; Czembor, Christina; Morisette, Jeffrey T.
2016-01-01
State-and-Transition Simulation Modeling (STSM) is a quantitative analysis method that can consolidate a wide array of resource management issues under a “what-if” scenario exercise. STSM can be seen as an ensemble of models, such as climate models, ecological models, and economic models that incorporate human dimensions and management options. This chapter presents STSM as a tool to help synthesize information on social–ecological systems and to investigate some of the management issues associated with exotic annual Bromus species, which have been described elsewhere in this book. Definitions, terminology, and perspectives on conceptual and computer-simulated stochastic state-and-transition models are given first, followed by a brief review of past STSM studies relevant to the management of Bromus species. A detailed case study illustrates the usefulness of STSM for land management. As a whole, this chapter is intended to demonstrate how STSM can help both managers and scientists: (a) determine efficient resource allocation for monitoring nonnative grasses; (b) evaluate sources of uncertainty in model simulation results involving expert opinion, and their consequences for management decisions; and (c) provide insight into the consequences of predicted local climate change effects on ecological systems invaded by exotic annual Bromus species.
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Aanderud, Zachary T.; Schoolmaster, Donald R.; Rigby, Deborah; Bybee, Jordon; Campbell, Tayte; Roundy, Bruce A.
2017-01-01
To stem wildfires, trees are being mechanically shredded into firebreaks with the resulting fine woody debris (FWD) potentially exerting immense control over soil and plants. We linked FWD-induced changes in microbial activity and nutrient availability to the frequency of Bromus tectorum and three native, perennial grasses across 31 piñon-juniper woodlands, UT, USA. Using a series of mixed models, we found that FWD increased the frequency of three of the four grasses by at least 12%. Deep, as opposed to shallow, soils mediated frequencies following FWD additions but only partially explained the variation in Bromus and Pseudoroegneria spicata. Although fertile areas associated with tree-islands elicited no response, FWD-induced increases in nitrogen mineralization in deep soils (15–17 cm) caused the frequency of the exotic and Pseudoroegneria to rise. Higher phosphorus availability in FWD-covered surface soils (0–2 cm) had no impact on grasses. FWD altered deep soil respiration, and deep and shallow microbial biomass structuring Pseudoroegneria frequencies, suggesting that microorganism themselves regulated Pseudoroegneria. The positive effects of FWD on grass frequencies intensified over time for natives but diminished for Bromus. Our results demonstrate that microorganisms in deeper soils helped mediate species-specific responses to disturbance both facilitating exotic invasion and promoting native establishment.
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Directory of Open Access Journals (Sweden)
Giraldo-Cañas Diego
2009-06-01
Full Text Available Se presenta un estudio taxonómico de las especies de Sporobolus para el noroeste de Sudamérica. Se reconocen once especies para el área de estudio. Se incluyen las claves para determinar las especies así como las descripciones morfológicas y sus ilustraciones. Se discuten para cada una de las especies sus relaciones morfológicas, su distribución geográfica y sus preferencias ecológicas; adicionalmente, se relacionan sus usos y sus nombres comunes. Asimismo, se propone la lectotipificación para Sporobolus lasiophyllus Pilg. Por otra parte, se registran tres especies por primera vez para Colombia [Sporobolus pilifer (Trin. Kunth, Sporobolus tenuissimus (Mart. ex Schrank Kuntze y Sporobolus virginicus (L. Kunth]. Se excluyen de este tratamiento a Sporobolus brasiliensis (Raddi Hack. (=Eragrostis airoides Nees y Sporobolus domingensis (Trin. Kunth. Adicionalmente, se propone la adopción y la unificación de algunos términos morfológicos en agrostología, tales como caña, panoja, espiguilla, lema, antecio y cariopsis, en lugar de culmo, panícula, espícula, lemma, flósculo y cariopse-cariópside, respectivamente.
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Directory of Open Access Journals (Sweden)
G. de Martins
1982-06-01
Full Text Available Numa área situada no município de Lavras, MG, o desmatamento realizado há cerca de dez anos propiciou a formação de uma comunidade infestante dominada por Pteridium aquilium (L. Khun., te ndo como codominantes Imperara brasiliensis Trin. e Andropogon bicornis L.. Como fatores que mantém esta comu nidade devem ser considerados: a as queimadas intermiten te s; b a acidez do solo; c a alta percentagem de saturação de aluminio ; d a ação fitotóxica do próprio P. aquilinum; e a falta de palatabilidade das espécies dominantes.A forest was clearcutted about 10 years ago in Lavras county, MG, Brazil and today a natural successional stage community can be found. The dominant weed, in fitomass, coverage an hcight is the bracken-fern Pteridium aquilinum (L. Kuhn. The West Indian foxta il (Andropogon bicornis L. and the brazilian cogon grass (Imperata brasiliensis Trin. are the co-dominats weeds. Periodic burnings, soil acidity, high aluminium saturation and the phytotoxicity of the P. aquilinum itself are probably the factors which could explain the present community successional stage.
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Vapor Pressure of N,N’-Diisopropylcarbodiimide (DICDI)
2016-02-01
11. Furumoto, S. The Synthesis of Carbodiimides from N,N-Disubstituted Thioureas and 2- Chloro-4,6-dimethylpyrimidine, 2,4-Dichloropyrimidine or...N-Phenylbenzimidoyl Chloride . Journal of Synthetic Organic Chemistry, Japan 1975, 33, 748–752. 12. Kagami, H.; Hanzawa, N.; Suzuki, N.; Yamaguchi...25. Brozena, A.; Buchanan, J.H.; Miles, R.W., Jr.; Williams, B.R.; Hulet, M.S. Vapor Pressure of Triethyl and Tri-n- Propyl Phosphates and Diethyl
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International Nuclear Information System (INIS)
Shevtsova, N.L.; Yavnyuk, A.A.; Gudkov, D.Yi.
2012-01-01
Results of the investigation of common reed's (Phragmites australis (Trin) Ex. Steud.) biological characteristics under conditions of long-term ionizing radiation impact are represented. Indices of seeds' vitality and disorders are analyzed. Low vitality indices, significant ontogenesis disorders, and high percent of abnormalities of germs are determined in water bodies, where littoral plants receive the absorbed dose in a low-dose range of 1-12 cGy year -1 .
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Directory of Open Access Journals (Sweden)
Instituto de Investigación en Ciencia Animal y Tecnología (IICAT
2015-10-01
Full Text Available This research work was conducted in the municipality of Santiago de Machaca which is the first section of the province, José Manuel Pando, it is located at the southeast of the Department of La Paz, at a distance of 205 km, from the city of La Paz. The objectives of this research were to: determine the biomass and floristic composition according to vegetative site, the stocking of native grasslands and the chemical composition of native prairie. The results were the following: the biomass composition and floristic composition is diverse, (35 native forrage species were identified in the vegetative site pampa, Marsh (11, hillside (18 and Hill (33. The capacity of stocking ability of (DC a stocking of native grasslands, Urtica flabellata (Itapallu (2.46; Bromus catharticus (bromus (1.26; Trifolium pratensis (Layulayu (1.38; Iberis sp. (tears of Virgin (1.55 and Hordium muticum (tail of mouse (1.64. Regarding chemical composition, the forage species with higher crude protein content of (% is Urtica flabellata (Itapallu, Bromus catharticus (bromus, 181,66 is 25.77%, forage species with higher energy content Kcal100/g Kcal100/g. and forage specie with higher content of iron mg / 100 g was Iberis sp. (Tears of Virgin, 20,97 mg / 100g. These identified species should be preserved and disseminated, since they showed greater amount of production and quality in content of nutrients required by animals. The conservation of these native species identified improve weight gain, consumption of native forage throughout the year, the chemical content, these native species studied, improve quality and cover the requirements from consumption of dry matter and nutrients required by animals. Finally this condition will positively affect the economy of the producers. It is recommended that these native species should be preserved and disseminated on the Prairies, since they showed greater amount of production and quality in content of nutrients required by animals.
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Miguel CAÑEDO-ARGÜELLES; Maria RIERADEVALL
2009-01-01
The epiphytic macroinvertebrate communities associated with the Common Reed, Phragmites australis (Cav.) Trin. ex Steudel, were examined seasonally from summer 2004 to spring 2005 in eleven coastal lagoons of the Llobregat Delta (NE Spain) following the method proposed by Kornijów & Kairesalo (1994). The aims of the study were to: 1) characterise and quantify changes in epiphytic macroinvertebrate communities along environmental gradients; 2) assess the contribution of elements of the epi...
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The weed infestation of extensively managed grass stands
Czech Academy of Sciences Publication Activity Database
Kocourková, Daniela; Fuksa, R.; Hakl, J.; Hlavičková, D.; Mrkvička, J.
2008-01-01
Roč. 2008, Sp.Iss.21 (2008), s. 561-564 ISSN 1861-3829 Institutional research plan: CEZ:AV0Z50380511 Keywords : Bromus inermis * Festuca arundinacea * Festulolium Subject RIV: EF - Botanics Impact factor: 0.566, year: 2008
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CSIR Research Space (South Africa)
Cho, Moses A
2009-01-01
Full Text Available species include Brachypodium genuense, Briza media, Bromus erectus and 101 Festuca sp. Herbs include Helichrysum italicum, Galium verum, Trifolium pratense, Plantago 102 lanceolata, Sanguisorba officinalis and Ononis spinosa. 103 104 2.2. Field data...
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Ecology, genetics, and biological control of invasive annual grasses in the Great Basin
Several annual grass species native to Eurasia, including cheatgrass (Bromus tectorum), red brome (B. rubens), and medusahead (Taeniatherum caput-medusae) have become invasive in the western USA. These invasive species degrade rangelands by compromising forage, outcompeting native flora, and exacerb...
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The ecological integrity of riparian areas is reduced by biological plant invaders like smooth brome grass (Bromus inermis). Smooth brome actively invades recently disturbed riparian zones by its high seed production and fast seedling establishment. Restoring native perennial grasses to these regio...
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The interrelationship between invasive annual grass abundance and soil resource availability varies spatially and temporally within ecosystems and may be altered by land treatments. We evaluated these relationships in two salt desert landscapes where the local abundance of Bromus tectorum L. (downy...
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No effect of ploidy level in plant response to competition in a common garden experiment
Czech Academy of Sciences Publication Activity Database
Münzbergová, Zuzana
2007-01-01
Roč. 92, - (2007), s. 211-219 ISSN 0024-4066 R&D Projects: GA AV ČR KJB6111303 Institutional research plan: CEZ:AV0Z60050516 Keywords : adaptation * Asteraceae * Bromus erectus Subject RIV: EF - Botanics Impact factor: 2.368, year: 2007
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Process-based management approaches for salt desert shrublands dominated by downy brome
Downy brome grass (Bromus tectorum L.) invasion has severely altered key ecological processes such as disturbance regimes, soil nutrient cycling, community assembly, and successional pathways in semi-arid Great Basin salt desert shrublands. Restoring the structure and function of these severly alte...
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Gardens and Gateways: Journeys within the Vision of Han-shan
Directory of Open Access Journals (Sweden)
Anne Beidler
2011-04-01
Full Text Available Although rooted in the work of the T’ang poet Han-shan, this paper is ultimately about the ways in which writers and artists engage with what they experience in the world. The work of filmmaker Trin T Minh-Ha, poems by W.S. Merwin, Burtin Watson’s translations, and the thoughts on the creative process of translation by Tony Barnstone and Gary Snyder have all informed my work as an artist and the images I present here.
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Kopf, Tamara; Galić, Slavka; Matešić, Krunoslav
2016-01-01
The aim of this study was to examine the efficiency of the validity scales (F, Fb, Fp, F-K, K, L, S, VRIN and TRIN) of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) in the detection of malingering mixed anxiety-depressive disorder and the possibility of differentiating between groups of persons with mixed anxiety-depressive disorder and persons instructed to malinger the mixed anxiety-depressive disorder on the basis of basic and content scales. The participants in the study were...
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Soil modification by invasive plants: Effects on native and invasive species of mixed-grass prairies
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.
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Phenology of exotic invasive weeds associated with downy brome
The exotic and highly invasive annual grass downy brome (Bromus tectorum) has invaded millions of hectares of rangelands throughout the Intermountain West. Downy brome increases the chance, rate, season and spread of wildfires, resulting in the destruction of native plant communities and the wildli...
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Population level response of downy brome to soil growing medium
Downy brome (Bromus tectorum) is the most ubiquitous exotic invasive weed in the Intermountain West. A major issue for management is the extreme generalist plastic nature of downy brome. We hypothesized that soil growing medium would effect all measured response variables representing some degree of...
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Forage production of grass-legume binary mixtures on Intermountain Western USA irrigated pastures
A well-managed irrigated pasture is optimized for forage production with the use of N fertilizer which incurs extra expense. The objective was to determine which binary grass-legume mixture and mixture planting ratio of tall fescue (Festuca arundinacea Schreb.) (TF), meadow brome (Bromus bieberstei...
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Downy Brome: evidence for soil engineering
Bromus tectorum L. (downy brome, cheatgrass) is an invasive Eurasian grass largely responsible for landscape level conversion of sagebrush/bunchgrass communities to annual grass dominance. We tested the hypothesis that B. tectorum alters or “engineers” the soil to favor its growth. The hypothesis wa...
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Downy brome seed ecology: From flower to emergence
Downy brome (Bromus tectorum) seed is very common in seed banks throughout Great Basin rangelands. Previously, using a soil bioassay method, we tested 100 separate sites within the Great Basin (1000 samples) to measure downy brome seed bank densities. The locations differed greatly by precipitation,...
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Increased wildfires in the western U.S. are due to the cyclic accumulation and burning of invasive annual plants such as cheatgrass (Bromus tectorum) and red brome (B. rubens), which reduces native rangeland species and results in servere economic losses and land degradation. Fire was not prevalent...
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Competition for soil nitrate and invasive weed resistance of three shrub-steppe growth forms
Eamonn D. Leonard
2007-01-01
Determining mechanisms responsible for weed resistance and invasion success are two issues that have potential in aiding successful land management decisions. The first experiment evaluates the competitive effects of an invasive annual grass downy brome (Bromus tectorum L.), an invasive biennial forb dyer's woad (Isatis tinctoria...
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Increased wildfires in the western U.S. are due to the cyclic accumulation and burning of invasive annual plants such as cheatgrass (Bromus tectorum) and red brome (B. rubens), which reduces native rangeland species and results in severe economic losses and land degradation. Fire was not prevalent ...
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Allelochemicals Effect of Aqueous Leachate from Oudneya Africana R
African Journals Online (AJOL)
nesrine
2014-03-05
Mar 5, 2014 ... This present study was conducted to investigate the possible allelopathic effect of Oudneya africana. (donor species) on Bromus tectorum (weed species) and Triticum aestivum (cv. Sahel1; crop species) through germination bioassay experiment. B. tectorum is a winter annual grass that grows in winter.
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The importance of education in managing invasive plant species
Invasive plant species can establish in diverse environments and with the increase in human mobility, they are no longer restricted to isolated pockets in remote parts of the world. Cheat grass (Bromus tectorum L.) in rangelands, purple loosestrife (Lythrum salicaria L.) in wet lands and Canada this...
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1985-08-01
nitrocellulose con- taining samples was saturated bW incubaticn in 15 ml of a 10% milk-Trin-saline (MTS) solution C10% Carnation instant nonfat drW milk, 10 mM...saturation of all binding sites in the wells, the plates were then incubated overnight at 40C with 200 ul of 0.5% Carnation nonfat drW milk in sensi...in the subsequent oxidation of OPD and formation of an orange - *~ yellow chromagen. The reaction was allowed to proceed at room temperature for 30
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Changes in mycorrhiza development in maize induced by crop management practices
DEFF Research Database (Denmark)
Gavito, M.E.; Miller, M.H.
1998-01-01
(Zea mays L.) or with the original plant species in the field site, bromegrass (Bromus inermis Leys.) and alfalfa (Medicago sativa L.). The delay in mycorrhiza development after cropping with canola was also observed in samples taken from the field and in a bioassay, both conducted at the beginning...
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Allelotoxicity of Oudneya africana R. Br. aqueous leachate on ...
African Journals Online (AJOL)
This present study was conducted to investigate the possible allelopathic effect of Oudneya africana (donor species) on Bromus tectorum (weed species) and Triticum aestivum (cv. Sahel1; crop species) through germination bioassay experiment. B. tectorum is a winter annual grass that grows in winter wheat and other ...
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Germination phenology of some Great Basin native annual forb species
Tara A. Forbis
2010-01-01
Great Basin native plant communities are being replaced by the annual invasive cheatgrass Bromus tectorum. Cheatgrass exhibits a germination syndrome that is characteristic of facultative winter annuals. Although perennials dominate these communities, native annuals are present at many sites. Germination timing is often an important predictor of competitive...
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The most common cause of successional retrogression in the Great Basin is wildfires fueled by downy brome (Bromus tectorum). Downy brome invasion has reduced fire intervals from an estimated 60-100 years down to 5-10 years. Our previous research found that establishment of long-lived perennial grass...
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Integrated management of downy brome in winter wheat
Downy brome (Bromus tectorum L.), also known as cheatgrass, was introduced into North America from the Mediterranean area of Europe. It was first identified in the eastern United States in 1861, and by 1914 this invasive weed had spread throughout the continent. Downy brome is adapted to climates wi...
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Host status of barley to Puccinia coronata from couch grass and P. striiformis from wheat and brome
The pathogenicity and identity of a field sample (PcE) of crown rust fungus Puccinia coronata collected in Hungary on wild couch grass (Elytrigia repens) and of a field sample (Psb) of stripe rust (P. striiformis) collected in the Netherlands on California brome (Bromus carinatus) was studied. We fo...
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Host status of barley to Puccinia coronata from couch grass and P. striiformis from wheat and brome
Niks, R.E.; Heyzen, van S.; Szabo, L.J.; Alemu, S.K.
2013-01-01
The pathogenicity and identity was studied of a field sample (PcE) of crown rust fungus Puccinia coronata collected in Hungary on wild couch grass (Elymus repens) and of a field sample (Psb) of stripe rust (P. striiformis) collected in the Netherlands on California brome (Bromus carinatus). We
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grain and biomass yield reduction due to russian wheat aphid on ...
African Journals Online (AJOL)
ACSS
2015-05-25
May 25, 2015 ... farmers' management is far lower than under on- station and on-farm ... of seeds for improved varieties and insect pests and diseases. .... the control of D. noxia infestation by. Fenitrothion 50 ... International Education (SRF) and Rutgers. Foundation. ... wheat, related cereals and a Bromus grass species. pp.
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Highly invasive grasses (e.g. Bromus spp., Pennisetum ciliare, Taeniatherum caput-medusae) are largely unabated in much of the arid Western U.S., despite more than 70 years of control attempts with a wide array of tools and management practices. The development and sustained integration of new appro...
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Biological Survey, Buffalo River and Outer Harbor of Buffalo, New York. Volume II. Data Report.
1982-06-01
Arctium mimus Schk. (burdock) 3 3 Leonurus cardiaca L. 3 (motherwo-3 Oenothera biennia L. 3 3 (evening pri-rose) Galium AM ine L. 2 (bedstaw) Asclapias...Wild carrot Bromus japonicus Thumb. Japanese brome , Oenothera biennis L. Evening primrose Clematis virginiana Virgin’ s bower Bidens tripartita Beggar
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Huang, Xunbing; McNeill, Mark Richard; Ma, Jingchuan; Qin, Xinghu; Tu, Xiongbing; Cao, Guangchun; Wang, Guangjun; Nong, Xiangqun; Zhang, Zehua
2017-08-01
Oedaleus asiaticus B. Bienko is a persistent pest occurring in north Asian grasslands. We found that O. asiaticus feeding on Stipa krylovii Roshev. had higher approximate digestibility (AD), efficiency of conversion of ingested food (ECI), and efficiency of conversion of digested food (ECD), compared with cohorts feeding on Leymus chinensis (Trin.) Tzvel, Artemisia frigida Willd., or Cleistogenes squarrosa (Trin.) Keng. Although this indicated high food utilization efficiency for S. krylovii, the physiological processes and molecular mechanisms underlying these biological observations are not well understood. Transcriptome analysis was used to examine how gene expression levels in O. asiaticus gut are altered by feeding on the four plant species. Nymphs (fifth-instar female) that fed on S. krylovii had the largest variation in gene expression profiles, with a total of 88 genes significantly upregulated compared with those feeding on the other three plants, mainly including nutrition digestive genes of protein, carbohydrate, and lipid digestion. GO and KEGG enrichment also showed that feeding S. krylovii could upregulate the nutrition digestion-related molecular function, biological process, and pathways. These changes in transcripts levels indicate that the physiological processes of activating nutrition digestive enzymes and metabolism pathways can well explain the high food utilization of S. krylovii by O. asiaticus. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Notice of release of Mountain Home germplasm Sandberg bluegrass (selected germplasm, natural track)
Scott M. Lambert; Stephen B. Monsen; Nancy Shaw
2011-01-01
Mountain Home germplasm Sandberg bluegrass is a small, densely tufted short-lived perennial bunchgrass adapted to low elevation, semi-arid sites with long, hot growing seasons. Mountain Home's drought tolerance, competitive nature, and ease of establishment make it an excellent choice for post-fire restoration of cheatgrass (Bromus tectorum L.) dominated...
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Christopher M. McGlone; Carolyn Hull Sieg; Thomas E. Kolb; Ty Nietupsky
2012-01-01
Competition and resource availability influence invasions into native perennial grasslands by nonnative annual grasses such as Bromus tectorum. In two greenhouse experiments we examined the influence of competition, water availability, and elevated nitrogen (N) and phosphorus (P) availability on growth and reproduction of the invasive annual grass B. tectorum and two...
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Growth and nutrient content of herbaceous seedlings associated with biological soil crusts
R. L. Pendleton; B. K. Pendleton; G. L. Howard; S. D. Warren
2003-01-01
Biological soil crusts of arid and semiarid lands contribute significantly to ecosystem stability by means of soil stabilization, nitrogen fixation, and improved growth and establishment of vascular plant species. In this study, we examined growth and nutrient content of Bromus tectorum, Elymus elymoides, Gaillardia pulchella, and Sphaeralcea munroana grown in soil...
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O gênero Chloris (Poaceae) em Pernambuco, Brasil
Maciel, Jefferson Rodrigues; Silva, Wegliane Campelo da; Costa-e-Silva, Maria Bernadete
2013-01-01
Com o objetivo de colaborar com o conhecimento da riqueza de Poaceae em Pernambuco, foi estudado o gênero Chloris Sw. As coletas foram realizadas no estado, bem como dados foram coligidos de levantamento em herbários da região. Foram registradas sete espécies de Chloris em Pernambuco: C. barbata Sw., C. elata Desv., C. exilis Renv., C. gayana Kunth, C. orthonoton Döll, C. pycnothrix Trin. e C. virgata Sw. O gênero apresenta distribuição ampla em todas as zonas fitogeográficas do estado. Chlor...
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S. E. Meyer; M. Masi; S. Clement; T. L. Davis; J. Beckstead
2015-01-01
Pyrenophora semeniperda, an important pathogen in Bromus tectorum seed banks in semi-arid western North America, exhibits >4-fold variation in mycelial growth rate. Host seeds exhibit seasonal changes in dormancy that affect the risk of pathogen-caused mortality. The hypothesis tested is that contrasting seed dormancy phenotypes select for contrasting strategies...
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The ghost of outcrossing past in downy brome, an inbreeding annual grass
Susan E. Meyer; Sudeep Ghimire; Samuel Decker; Keith R. Merrill; Craig E. Coleman
2013-01-01
We investigated the frequency of outcrossing in downy brome (Bromus tectorum L.), a cleistogamous weedy annual grass, in both common garden and wild populations, using microsatellite and single nucleotide polymorphic (SNP) markers. In the common garden study, 25 lines with strongly contrasting genotypes were planted in close proximity. We fingerprinted 10 seed progeny...
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1985-09-01
bitterbrush Purshia glandulosa Apache plume Fallugia paradoxa Arizona fesce Festuca arizonica Ashe juniper Juniperus ashei Australian saltbush Atriplex...elm Ulmus crassifolia *Cheatgrass Bromus tectorum -Chinkapin oak Quercus muhlenbergii Cholla Opuntia, spp. * Cicer milkvetch Astragalus cicer Clovers...Linum lewisii Little bluestem Schizachyrium scoparium *Littleleaf palo verde Cercidium microphyllum *Live oak Quercus virginiana Lovegrasses Eragrostis
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Marco Masi; Susan Meyer; Alessio Cimmino; Anna Andolfi; Antonio Evidente
2014-01-01
A new phytotoxic sesquiterpenoid penta-2,4- dienoic acid, named pyrenophoric acid, was isolated from solid wheat seed culture of Pyrenophora semeniperda, a fungal pathogen proposed as a mycoherbicide for biocontrol of cheatgrass (Bromus tectorum) and other annual bromes. These bromes are serious weeds in winter cereals and also on temperate semiarid rangelands....
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Controlling cheatgrass in winter range to restore habitat and endemic fire
Jennifer L. Vollmer; Joseph G. Vollmer
2008-01-01
Habitat managers can better prepare a program for prescribed burns, wildfire management, and maximum forage biomass by understanding the response of key shrubs to the tools utilized to reduce cheatgrass (Bromus spp.) competition. Application of Plateau® herbicide, prior to annual brome germination, at rates up to 8 oz/acre with or without surfactant...
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Soil sulfur amendments suppress Selenium uptake by alfalfa and western wheatgrass
C. L. Mackowiak; M. C. Amacher
2008-01-01
Selenium (Se) is a potential soil contaminant in many parts of the world where it can pose a health risk to livestock and wildlife. Phosphate ore mining in Southeast Idaho has resulted in numerous waste rock dumps revegetated with forages to stabilize the dumps and support grazing. Alfalfa (Medicago sativa L.), smooth brome (Bromus inermis...
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Li, Danfeng; Wang, Xunming; Lou, Junpeng; Liu, Wenbin; Li, Hui; Ma, Wenyong; Jiao, Linlin
2018-02-01
The heterogeneity of the composition of surface soils that are affected by aeolian processes plays important roles in ecological evolution and the occurrence of aeolian desertification in fragile ecological zones, but the associated mechanisms are poorly understood. Using field investigation, wind tunnel experiments, and particle size and element analyses, we discuss the variation in the nutrient elements of surface soils that forms in the presence of aeolian processes of four vegetation species (Caragana microphylla Lam, Artemisia frigida Willd. Sp. Pl., Leymus chinensis (Trin.) Tzvel. and Stipa grandis P. Smirn) growing in the Otindag Desert, China. These four vegetation communities correspond to increasing degrees of degradation. A total of 40 macro elements, trace elements, and oxides were measured in the surface soil and in wind-transported samples. The results showed that under the different degradation stages, the compositions and concentrations of nutrients in surface soils differed for the four vegetation species. Aeolian processes may cause higher heterogeneity and higher loss of soil nutrient elements for the communities of Artemisia frigida Willd. Sp. Pl., Leymus chinensis (Trin.) Tzvel, and Stipa grandis P. Smirn than for the Caragana microphylla Lam community. There was remarkable variation in the loss of nutrients under different aeolian transportation processes. Over the past several decades, the highest loss of soil elements occurred in the 1970s, whereas the loss from 2011 to the present was generally 4.0% of that in the 1970s. These results indicate that the evident decrease in nutrient loss has played an important role in the rehabilitation that has occurred in the region recently.
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Lin, Hai; Liu, Junfei; Dong, Yingbo; Ren, Kaiqiang; Zhang, Yu
2018-04-20
The aim of the present study was to investigate three kinds of emergent macrophytes, i.e., Acorus calamus L., Phragmites communis Trin., and Alternanthera philoxeroides (Mart.) Griseb and their combination patterns on their removal efficiency of compound heavy metals (vanadium, chromium, and cadmium) from synthetic aqueous. The results showed that the optimal single-species for compound heavy metals removal was Acorus calamus L. and during experiment period, the average removal efficiency of V 5+ , Cr 6+ , and Cd 2+ was 52.4, 46.8, and 90.0%, respectively. Combination C (the quality ratio of Acorus calamus L., Phragmites communis Trin., and Alternanthera philoxeroides (Mart.) Griseb is 2:1:1) had the highest removal efficiency on compound heavy metals among three groups and the average removal efficiency of V 5+ , Cr 6+ , and Cd 2+ was 18.0, 70.0, and 95.1%, respectively. The highest efficiency of combination C on V 5+ removal was lower than single Alternanthera philoxeroides (Mart.) Griseb group; this may be an existing antagonism in different plants. Heavy metals of V 5+ , Cr 6+ , and Cd 2+ had an obviously positive effect on SOD, CAT, and POD of emergent macrophytes. From these results, we conclude that in a phytoremediation for the removal of compound heavy metals where V was dominated pollution in water, the use of Acorus calamus L. species rather than a mixture of several plants should be suggested. When heavy metal pollution was dominated by Cr and Cd, group C rather than a single plant species should be used.
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Treating downy brome with herbicide and seeding with native shrubs
Suzanne Owen; Carolyn Sieg
2011-01-01
Downy brome or cheatgrass (Bromus tectorum L.) is one of the most invasive and widespread exotic plants in North America. Downy brome can reduce soil nutrient availability, alter native plant community composition, and increase fire frequencies. The effectiveness of Plateau® imazapic herbicide in reducing downy brome cover has been variable, and there is uncertainty...
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Cheating cheatgrass: New research to combat a wily invasive weed
Gail. Wells
2012-01-01
Cheatgrass and its cousin, red brome, are exotic annual grasses that have invaded and altered ecosystem dynamics in more than 41 million acres of desert shrublands between the Rockies and the Cascade-Sierra chain. A fungus naturally associated with these Bromus species has been found lethal to the plants' soil-banked dormant seeds. Supported by the Joint Fire...
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De novo genome assembly of the fungal plant pathogen Pyrenophora semeniperda
Marcus M. Soliai; Susan E. Meyer; Joshua A. Udall; David E. Elzinga; Russell A. Hermansen; Paul M. Bodily; Aaron A. Hart; Craig E. Coleman
2014-01-01
Pyrenophora semeniperda (anamorph Drechslera campulata) is a necrotrophic fungal seed pathogen that has a wide host range within the Poaceae. One of its hosts is cheatgrass (Bromus tectorum), a species exotic to the United States that has invaded natural ecosystems of the Intermountain West. As a natural pathogen of cheatgrass, P. semeniperda has potential as a...
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Martins, G. de; Carvalho, D.A. de
1982-01-01
Numa área situada no município de Lavras, MG, o desmatamento realizado há cerca de dez anos propiciou a formação de uma comunidade infestante dominada por Pteridium aquilium (L.) Khun., te ndo como codominantes Imperara brasiliensis Trin. e Andropogon bicornis L.. Como fatores que mantém esta comu nidade devem ser considerados: a) as queimadas intermiten te s; b) a acidez do solo; c) a alta percentagem de saturação de aluminio ; d) a ação fitotóxica do próprio P. aquilinum; e) a falta de pala...
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International Nuclear Information System (INIS)
Prayitno; Djoko-Sardjono; Nurimaniwati; Adhe-Helmayani
2000-01-01
The influence of extractant and stirring time on the reduction componentcadmium on liquid wastes has been investigated. The method of experimentalused the extraction with liquid membrane emulsion. The parameters to beinvestigated were extractant amount tri-n octylamine (TOA), duration ofstirring time. In this investigated, extractant amount was varied from 5 to25 % (v/v) TOA, duration of stirring time varied from 5 to minutes. Theresult of experimental can be concluded that the best condition obtained forreducing cadmium component was on extractant amount 20 % (v/v) TOA, stirringtime 25 minutes. The best condition for reducing the cadmium component wasefficiency factor 98.35%. (author)
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Learning to live with cheatgrass: Giving up or a necessary paradigm shift?
Stanley G. Kitchen
2014-01-01
Natural ecosystems in the semiarid West face many stressors. Among the most challenging are those associated with invasive plant species. One invader that has had great impact over the last 100 years is the annual grass known as cheatgrass (Bromus tectorum). A few years ago, I made two observations that both confirmed and broadened my perception of this plant. In the...
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Aronson, J; Kigel, J; Shmida, A
1993-03-01
Reproductive effort (relative allocation of biomass to diaspore production) was compared in matched pairs of Mediterranean and desert populations of three unrelated annual species, Erucaria hispanica (L.) Druce, Bromus fasciculatus C. Presl. and Brachypodium distachyon (L.) Beauv., grown under high and low levels of water availability in a common-environment experiment. Desert populations in all three species showed higher reproductive effort than corresponding Mediterranean populations, as expressed by both a reproductive index (RI= reproductive biomass/vegetative biomass), and a reproductive efficiency index (REI=number of diaspores/total plant biomass). Moreover, in E. hispanica and Brachypodium distachyon, inter-populational differences in reproductive effort were greater under water stress, the main limiting factor for plant growth in the desert. These results indicate that variability in reproductive effort in response to drought is a critical and dynamic component of life history strategies in annual species in heterogeneous, unpredictable xeric environments. When subjected to water stress the Mediterranean populations of E. hispanica and B. distachyon showed greater plasticity (e.g. had a greater reduction) in reproductive effort than the desert populations, while in Bromus fasciculatus both populations showed similar amounts of plasticity.
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Interrelationship of MMPI-2 validity scales in personal injury claims.
Fox, D D; Gerson, A; Lees-Haley, P R
1995-01-01
A sample of MMPI-2s of worker's compensation and personal injury cases (N = 289) was gathered to examine the relationship of various indicators of exaggeration. Intercorrelations of the F, F-K, the MMPI Dissimulation Scale-revised (Ds-r), total of obvious minus subtle scales (O-S), Fake Bad Scale (FBS), VRIN, and TRIN were computed and the relative sensitivity of each score calculated using various cut-offs. Factor analysis suggests that malingering may take the form of inconsistent responding as well as symptom exaggeration. Patients evaluated at the request of plaintiff attorneys showed a seemingly greater degree of symptom exaggeration and inconsistent responding than did those referred by defense counsel.
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Neutron spin filter based on optically polarized sup 3 He in a near-zero magnetic field
Skoy, V R; Sorokin, V N; Kolachevsky, N N; Sobelman, I I; Sermyagin, A V
2003-01-01
A test of polarization of sup 3 He nuclei via spin-exchange collisions with optically pumped rubidium atoms in an extremely low applied magnetic field was carried out. Permalloy magnetic shields were used to prevent a fast relaxation of sup 3 He polarization owing to the inhomogeneity of a surrounding magnetic field. The whole installation was placed at the neutron beam line of the IBR-30 facility, and used as a neutron spin filter. Thus, a prototype of new design of neutron polarizer was introduced. We intend to apply this experience for the full-scale KaTRIn facility to test the time reversal violation in neutron-nuclear reactions.
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Basic chromosome numbers and polyploid levels in some South African and Australian grasses (Poaceae
Directory of Open Access Journals (Sweden)
J. J. Spies
1991-10-01
Full Text Available Chromosome numbers of 46 specimens of grasses, involving 24 taxa from South Africa and Australia, have been determined during the present study. For the first time chromosome numbers are given for Eragrostis sarmentosa (Thunb. Trin. (n = 20. Panicum aequinerve Nees (n = 18, Digitaria argyrograpta (Nees Stapf (n = 9 and D. maitlandii Stapf & C.E. Hubb. (n = 9. Additional polyploid levels are described for Diplachne fusca (L. Beauv. ex Roem. & Schult. (n = 10 and Digitaria diagonalis (Nees Stapf var. diagonalis (n = 9. B-chromosomes were observed in several different specimens. The presence of B-chromosomes often results in abnormal chromosomal behaviour during meiosis.
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Temporal priority effects on competition are not consistent among intermountain grassland species
Zuo, Shengpeng; Li, Hongli; Ma, Yongqing; Callaway, Ragan M.
2016-08-01
Previous work indicates that priority effects exist, but mechanisms are not well understood. So we explored shifts in competitive outcomes and intensities as a potential general mechanism. In a standard greenhouse experiment the temporal priority effects of the target species Pseudoroegneria spicata and its competitive responses to five receptor species, i.e., Bromus ciliatus, Bromus marginatus, Coreopsis tinctoria, Senecio atratus, and Solidago canadensis were evaluated. P. spicata adults with a high root: shoot ratio had a significant inhibitory priority effect on B. ciliatus, B. marginatus, and C. tinctoria. Compared with the target species, under later and simultaneous sowing, B. ciliatus, B. marginatus, C. tinctoria, and S. atratus exhibited an increasing trend in terms of competition. However, S. canadensis did not display priority effects. In addition, the gram per gram competitive effect of P. spicata depended on the receptor species in the following order: B. marginatus > B. ciliatus > C. tinctoria > S. atratus. There were positive relationships between the relative interaction indices and the root: shoot ratios in B. ciliatus, B. marginatus, and C. tinctoria, thereby suggesting that the early germination or emergence of P. spicata may reduce the root: shoot ratios of these receptors. The results of this study indicate that priority effects occurred in early colonizers with high root: shoot ratios and greater competitive capacities.
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Bernhardt, Nadine; Brassac, Jonathan; Kilian, Benjamin; Blattner, Frank R
2017-06-16
Triticeae, the tribe of wheat grasses, harbours the cereals barley, rye and wheat and their wild relatives. Although economically important, relationships within the tribe are still not understood. We analysed the phylogeny of chloroplast lineages among nearly all monogenomic Triticeae taxa and polyploid wheat species aiming at a deeper understanding of the tribe's evolution. We used on- and off-target reads of a target-enrichment experiment followed by Illumina sequencing. The read data was used to assemble the plastid locus ndhF for 194 individuals and the whole chloroplast genome for 183 individuals, representing 53 Triticeae species and 15 genera. We conducted Bayesian and multispecies coalescent analyses to infer relationships and estimate divergence times of the taxa. We present the most comprehensive dated Triticeae chloroplast phylogeny and review previous hypotheses in the framework of our results. Monophyly of Triticeae chloroplasts could not be confirmed, as either Bromus or Psathyrostachys captured a chloroplast from a lineage closely related to a Bromus-Triticeae ancestor. The most recent common ancestor of Triticeae occurred approximately between ten and 19 million years ago. The comparison of the chloroplast phylogeny with available nuclear data in several cases revealed incongruences indicating past hybridizations. Recent events of chloroplast capture were detected as individuals grouped apart from con-specific accessions in otherwise monopyhletic groups.
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DEFF Research Database (Denmark)
Hvidtfeldt, Susanne; Sjøstedt, Lotte Ebsen
Bag facaden er et task-baseret materiale der går bag om danskerne kulturelt og sprogligt. Det henvender sig til spor 3-learnere på de sidste trin, men kan i nogle klasser godt anvendes tidligere. Teksterne i bogen er autentiske dagbogsnotater skrevet af danskere i alle aldre. Den nærværende og...... eller hun er i sin sprogtilegnelse og i sit behov for viden om dansk kultur og samfund. Derudover forbereder det fint learneren til almenprøve 2 og DUF eksamen, både hvad angår indhold og arbejdsformer. I forløb hvor der stiles mod folkeskolens afgangseksamner er Bag facaden relevant som supplerende...
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Adaptive restoration of river terrace vegetation through iterative experiments
Dela Cruz, Michelle P.; Beauchamp, Vanessa B.; Shafroth, Patrick B.; Decker, Cheryl E.; O’Neil, Aviva
2014-01-01
Restoration projects can involve a high degree of uncertainty and risk, which can ultimately result in failure. An adaptive restoration approach can reduce uncertainty through controlled, replicated experiments designed to test specific hypotheses and alternative management approaches. Key components of adaptive restoration include willingness of project managers to accept the risk inherent in experimentation, interest of researchers, availability of funding for experimentation and monitoring, and ability to restore sites as iterative experiments where results from early efforts can inform the design of later phases. This paper highlights an ongoing adaptive restoration project at Zion National Park (ZNP), aimed at reducing the cover of exotic annual Bromus on riparian terraces, and revegetating these areas with native plant species. Rather than using a trial-and-error approach, ZNP staff partnered with academic, government, and private-sector collaborators to conduct small-scale experiments to explicitly address uncertainties concerning biomass removal of annual bromes, herbicide application rates and timing, and effective seeding methods for native species. Adaptive restoration has succeeded at ZNP because managers accept the risk inherent in experimentation and ZNP personnel are committed to continue these projects over a several-year period. Techniques that result in exotic annual Bromus removal and restoration of native plant species at ZNP can be used as a starting point for adaptive restoration projects elsewhere in the region.
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International Nuclear Information System (INIS)
Metwally, E.; Saleh, A.Sh.; El-Naggar, H.A.
2005-01-01
Extraction of U(VI) and Th(IV) from chloride and nitrate solutions with tri-n- dodecylamine impregnated on Amberlite XAD4, was investigated. The distribution of U(VI) and Th(IV) was studied at different concentrations of acid, salting-out agent, extractant, aqueous metal ion and other parameters. Absorption spectral studies have been investigated for uranium species in both aqueous HCl solution and the resin phase. From these studies, it is suggested that the tetrachloro complex of U(VI) is formed in the extraction of uranium (VI) from hydrochloric acid solutions by TDA impregnated resin. Stripping of the extracted U(VI) and Th(IV) was assayed with HCl and HNO 3 . Finally, the separation of uranium from thorium and fission products in HCl media was achieved
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Studies on the reproductive biology of downy brome (Bromus tectorum)
International Nuclear Information System (INIS)
Richardson, J.M.
1986-01-01
The ability of downy brome to successfully infest crop lands is partially due to its prolific nature. To better understand its reproductive biology, studies investigating (1) effects of temperature and photoperiod on flowering, (2) prevention of downy brome seed information with herbicides, and (3) effects of drought on reproduction, were conducted. Seedling vernalization was more effective than seed vernalization in promoting downy brome flowering. Vernalizing imbibed downy brome caryopses at 3 C for 0 to 30 days did not induce rapid flowering. Downy brome seedlings were exposed to six photoperiod/temperature treatments. After transfer to long days, plants from the short da/3 C treatment flowered within 30 days. DPX-Y6202 and fluazifop-butyl were tested for their ability to prevent seed formation in downy brome. Fluazifop-butyl prevented seed formation over a wider range of application rates and growth stages than did DPX-Y6202. Seed production was prevented most readily by herbicide applications made early in the reproductive cycle. Translocation of radiolabel was greater with 14 C-fluazifop-butyl than with 14 C-DPX-Y6202, particularly into developing spikelets. Microautoradiographic techniques were used to identify mechanisms involved in the prevention of downy brome seed formation by these herbicides. Tissue localization of both herbicides was similar. The highest concentration of radiolabel was found in developing pollen grains, suggesting that the herbicides prevented seed formation by interrupting pollen development or function. Water stress reduced apparent photosynthesis and increased diffusive resistance of flag leaves
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Conditions favouring Bromus tectorum dominance of endangered sagebrush steppe ecosystems
Reisner, Michael D.; Grace, James B.; Pyke, David A.; Doescher, Paul S.
2013-01-01
1. Ecosystem invasibility is determined by combinations of environmental variables, invader attributes, disturbance regimes, competitive abilities of resident species and evolutionary history between residents and disturbance regimes. Understanding the relative importance of each factor is critical to limiting future invasions and restoring ecosystems.
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New contributions to the knowledge of the alien flora in Baix Llobregat county (Catalonia, Spain
Directory of Open Access Journals (Sweden)
H. Álvarez
2016-08-01
Full Text Available We provide new records of 17 exotic plants in the Baix Llobregat region observed between the years 2011 and 2014. Two species are the first records for Europe: Acacia rostellifera Benth. and Trichloris crinita (Lag. Parodi; two are new plants for the Iberian Peninsula: Bouteloua dactyloides (Nutt. Columbus and Nassella tenuissima (Trin. Barkworth; three are recorded by their first time in Catalonia: Atriplex semibaccata R. Br., Oenothera speciosa Nutt. and Verbena incompta P. W. Michael; five correspond to first records in Baix Llobregat: Parkinsonia aculeata L., Phacelia tanacetifolia Benth., Physalis peruviana L., Salpichroa origanifolia (Lam. Baill. and Verbena brasiliensis Vell. The remaining species are very rare in the studied area: Abutilon grandifolium (Willd. Sweet, Asperugo procumbens L., Eclipta prostrata (L. L. and Oenothera indecora Cambess.
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Atlantis Star – a new herbicide in cereals with efficacy against grasses and dicots
Directory of Open Access Journals (Sweden)
Kerlen, Dirk
2016-02-01
Full Text Available Atlantis Star (mesosulfuron-methyl; iodosulfuron-methyl-sodium; thiencarbazone-methyl; mefenpyr-diethyl is a new cereal herbicide to control blackgrass (Alopecurus myosuroides; sensitive and high infestation, brome grass (Bromus spec., ryegrass (Lolium spec., wild oat (Avena fatua, loose silky-bentgrass (Apera spica-venti L., annual meadow-grass (Poa annua L. and dicot weeds. Atlantis Star can be used in winter wheat, winter triticale, winter rye, winter durum wheat and spelt. The publication is based on efficacy trials from two years of spring application with Atlantis Star.
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Directory of Open Access Journals (Sweden)
Felipe Correa de Mello
2014-07-01
Full Text Available Este texto busca discutir e correlacionar o trinômio comunicação-consumo-entretenimento no âmbito do universo dos games eletrônicos. A centralidade das relações proposta neste trabalho examina especificamente uma característica do console Playstation 3 - da marca Sony - que conjuga entretenimento, rede social e recompensas simbólicas. Para dar conta de um objeto com tamanha complexidade trazemos para este estudo dois aportes nucleares: 1 reflexões sobre do universo dos games e do entretenimento; 2 considerações acerca da noção de campo social, interações sociais e dinâmicas das trocas simbólicas. Para focarmos o escopo da discussão, utilizaremos o jogo exclusivo de Playstation 3, The Last of Us (Naughty Dog, 2013, como objeto de estudo.
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The distribution and accumulation of chromium in the water, sediment and macrophytes of Skadar lake
Directory of Open Access Journals (Sweden)
Kastratović Vlatko
2016-01-01
Full Text Available The aquatic macrophytes Phragmites australis (Cav. Trin. ex Steud., Ceratophyllum demersum L., and Lemna minor L. were used as bioindicator plant species in order to define contamination level by Cr in Skadar lake (Montenegro. Plants, water and sediments were tested for the content of Cr at six locations around Lake Skadar during four periods in 2011. The content of Cr in the examined sediment was in the range of 35.6-127 mg/kg dry weight. The largest proportion of detected Cr (50.6% was associated with the oxidizable phase in the form of organic complexes. The concentration of Cr in the studied macrophytes declined in the following order: C. demersum > P. australis > L. minor. The highest average content of Cr was detected in the leaf of C. demersum (11.4 mg/kg in April.
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Hawkes, C.V.; Belnap, J.; D'Antonio, C.; Firestone, M.K.
2006-01-01
Plant invasions have the potential to significantly alter soil microbial communities, given their often considerable aboveground effects. We examined how plant invasions altered the arbuscular mycorrhizal fungi of native plant roots in a grassland site in California and one in Utah. In the California site, we used experimentally created plant communities composed of exotic (Avena barbata, Bromus hordeaceus) and native (Nassella pulchra, Lupinus bicolor) monocultures and mixtures. In the Utah semi-arid grassland, we took advantage of invasion by Bromus tectorum into long-term plots dominated by either of two native grasses, Hilaria jamesii or Stipa hymenoides. Arbuscular mycorrhizal fungi colonizing roots were characterized with PCR amplification of the ITS region, cloning, and sequencing. We saw a significant effect of the presence of exotic grasses on the diversity of mycorrhizal fungi colonizing native plant roots. In the three native grasses, richness of mycorrhizal fungi decreased; in the native forb at the California site, the number of fungal RFLP patterns increased in the presence of exotics. The exotic grasses also caused the composition of the mycorrhizal community in native roots to shift dramatically both in California, with turnover of Glomus spp., and Utah, with replacement of Glomus spp. by apparently non-mycorrhizal fungi. Invading plants may be able to influence the network of mycorrhizal fungi in soil that is available to natives through either earlier root activity or differential carbon provision compared to natives. Alteration of the soil microbial community by plant invasion can provide a mechanism for both successful invasion and the resulting effects of invaders on the ecosystem. ?? Springer 2006.
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Atlantis FLEX (BAY 22010 H – a new herbicide in cereals with efficacy against grasses
Directory of Open Access Journals (Sweden)
Kerlen, Dirk
2014-02-01
Full Text Available Atlantis FLEX (Mesosulfuron-methyl; Propoxycarbazone-sodium; Mefenpyr-diethyl is a new cereal herbicide to control blackgrass (Alopecurus myosuroides, ryegrass (Lolium spec., brome grass (Bromus spec., wild oat (Avena fatua, loose silky-bentgrass (Apera spica-venti L, annual meadow-grass (Poa annua L. and dicot weeds. Atlantis FLEX can be used in winter wheat, winter triticale, winter rye, winter durum wheat and spelt. The publication is based on efficacy trials from two years of spring application with Atlantis FLEX. It will be shown, that Atlantis FLEX generates a good to excellent efficacy against grass-weeds.
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Smooth brome (Bromus inermis Leyss) response to concrete grinding residue application
Concrete grinding residue (CGR) is a slurry byproduct created by concrete pavement maintenance operations. The application of CGR to roadside soils is not consistently regulated by state agencies across the United States. Much of this variability in regulation may be due to the lack of science-base...
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Directory of Open Access Journals (Sweden)
BRUNA KRIMBERG VON MUHLEN
2015-02-01
Full Text Available Neste ensaio contextualizamos o panorama em que se encontram as mulheres e o HIV. Encadeamos nossas reflexões sobre o empoderamento das mulheres com a teoria de Krista Burlae e a psicologia feminista. Estabelecemos relações entre a hierarquia de gênero e a manutenção da vulnerabilidade feminina presentes nas configurações conjugais heterossexuais e seus efeitos na saúde sexual das mulheres. Enfatizamos o empoderamento das mulheres como um fator de prevenção a ser considerado. Propomos partir dos dados estatísticos relativos à epidemia do HIV/AIDS para centrar atenção na saúde global das mulheres e articular vida privada e saúde pública. Diante das reflexões realizadas entendemos ser necessário transformar o trinômio mulheres/saúde sexual /saúde pública.
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International Nuclear Information System (INIS)
Pattee, D.; Musikas, C.; Faure, A.; Chachaty, C.
1986-09-01
To operate a trivalent actinide-lanthanide (III) group chemical separation from low pH nitric solutions we studied the extractive properties of the di-2 ethyl hexyl dithiophosphoric acid (HDEHDTP); this bidentate ligand which possesses a sulfur donor atom is a good extractant of soft acids. We so expect a better selectivity for the actinides (III) extraction. We also have investigated extractive properties of di-2 ethyl hexyl monothiophosphoric acid (HDEHTP) for trivalent actinides and lanthanides; HDEHDTP is a bidentate ligand with one oxygen donor atom and so is a better extractant for hard acids like actinides and lanthanides (III); but its selectivity is weak. The addition of TBP (tri-n butyl phosphate) to HDEHDTP deals to strong synergistic organic complexes with a great selectivity for Am(III). We explicited this phenomenon. When the metal is macroconcentrated the organic complexes aggregate and form inverted micelles
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Behaviour and failure of C-Mn steel in presence of ageing under strain
International Nuclear Information System (INIS)
Belotteau Schroeder, Jeanne
2009-01-01
As carbon-manganese (C-Mn) steels are largely used in various mechanical applications, and more particularly in secondary circuit pipes of pressurized water nuclear reactors (PWR), this research thesis reports the behaviour and failure modelling of such a steel within a large temperature domain (between 20 and 350 deg C). Tensile tests have been performed on smooth samples and on notches axisymmetric samples, and tear tests have been performed on CT samples. The model of Es trin Kubin-McCormick which takes ageing under strain into account has been used to simulate most of the effects of ageing under strain: negative sensitivity of flow stress to strain rate, Luders bands, PLC effect, modification of tensile mechanical properties, so on. The model is applied to the considered samples. In order to predict the failure of notched specimens, a failure local approach has been applied [fr
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Anther and pollen development in some species of Poaceae (Poales
Directory of Open Access Journals (Sweden)
AT. Nakamura
Full Text Available Anther and pollen development were studied in Olyra humilis Nees, Sucrea monophylla Soderstr, (Bambusoideae, Axonopus aureus P. Beauv., Paspalum polyphyllum Nees ex Trin. (Panicoideae, Eragrostis solida Nees, and Chloris elata Desv. (Chloridoideae. The objective of this study was to characterise, embryologically, these species of subfamilies which are considered basal, intermediate and derivate, respectively. The species are similar to each other and to other Poaceae. They present the following characters: tetrasporangiate anthers; monocotyledonous-type anther wall development, endothecium showing annular thickenings, secretory tapetum; successive microsporogenesis; isobilateral tetrads; spheroidal, tricellular, monoporate pollen grains with annulus and operculum. Nevertheless, the exine patterns of the species studied are distinct. Olyra humilis and Sucrea monophylla (Bambusoideae show a granulose pattern, whereas in the other species, it is insular. In addition, Axonopus aureus and Paspalum polyphyllum (Panicoideae have a compactly insular spinule pattern, while Chloris elata and Eragrostis solida (Chloridoideae show a sparsely insular spinule pattern. The exine ornamentation may be considered an important feature at the infrafamiliar level.
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Dansk oversættelse af MiDAS, et redskab til assessment af musikterapi for personer med demens
DEFF Research Database (Denmark)
Ridder, Hanne Mette Ochsner; Lykkegaard, Chris; McDermott, Orii
2018-01-01
DAS explored which procedures is used for outcome measure translation and cultural adaptation, and based on this recommended a ten-step procedure. We applied this procedure in order to translate MiDAS and hereby develop the Danish MiDAS-DK. The Danish MiDAS version has been tested by more than 20 professionals......) musikterapeuten umiddelbart efter sessionen for at vurdere forandringer i selve sessionen. Der har været stor interesse for at anvende MiDAS i flere Europæiske lande, herunder Danmark. Derfor undersøgte udviklerne af MiDAS hvilke procedurer der anvendes til oversættelse og kulturel tilpasning af...... assessmentredskaber, og anbefalede på den baggrund en ti-trins procedure. Vi anvendte denne procedure til oversættelsen af MiDAS og således udviklingen af den danske MiDAS-DK. Den danske version af MiDAS er afprøvet af mere end 20 fagpersoner på baggrund af 296 udfyldte MiDAS-skemaer. Målet med artiklen er...
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A decifração de um enigma: o título "Esmeraldo de Situ Orbis"
Directory of Open Access Journals (Sweden)
Joaquim Barradas de Carvalho
1964-06-01
Full Text Available O título da célebre obra de Duarte Pacheco Pereira é composto pela palavra Esmeraldo e pela expressão De Situ Orbis. A compreensão da expressão De Situ Orbis não apre-senta a mínima dificuldade. Todos os autores que abordaram o assunto foram unânimes em considerar que se trata do título da obra geográfica de Pompônio Mela, citada aliás uma trin-tena de vêzes por Duarte Pacheco Pereira, e que é, com a História Natural de Plínio, uma das suas duas fontes funda-mentais . Outro tanto não poderemos dizer da primeira parte do título, a palavra Esmeraldo, sôbre a decifração da qual mais de meia dúzia de teses foram até agora elaboradas sem que a unanimidade se tenha feito sôbre nenhuma delas.
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BIODIVERSIDADE FLORESTAL E PAISAGÍSTICA DO TERRITÓRIO MUNICIPAL DE SELLANO - ÚMBRIA - ITÁLIA
Directory of Open Access Journals (Sweden)
Ettore Orsomando
2007-08-01
Full Text Available O Município de Sellano, situado na Úmbria (Itália, ocupando uma superfície de cerca 86 km² no setor regional central mais oriental junto à fronteira com as Marcas, do ponto de vista florestal se destaca pelo elevado índice de cobertura florestal superior a 60% em relação aos 40% da Úmbria. A biodiversidade florestal é constituída por 7 formações de caducifólias naturais (florestas: de Quercus pubescens, de Ostrya carpinifolia, de Quercus cerris com a associação endêmica denominada Carici sylvaticae-Quercetum cerridis rica em Orquídeas, de Quercus cerris com Quercus pubescens, de Castanea sativa, de Fagus sylvatica, de Salix alba e por um artificialismo (reflorestamentos de Pinusnigra e Pinus halepensis. Tais florestas, voltadas para a exploração econômica, em bom estado de conservação, contornadas por áreas de pastagem, por áreas antrópicas com ocupações humanas, áreas cultivadas e zonas de artesanato caracterizam 11 unidades ambientais paisagísticas do conjunto das 42 tipologias de paisagens da Região Úmbria como um todo: vertentes alto-colinares com florestas de Quercus pubescens ou de Ostrya carpinifolia, às vezes interrompidas por pequenas clareiras de pastagens, de origem secundária, de Bromus erectus; vertentes montanas com florestas de Fagus sylvatica e pequenas pastagens, de origem secundária, de Bromus erectus; áreas rupestres com agrupamentos casmofiticos; vertentes alto-colinares e submontanas, com fraca declividade e recobertas por paleossolos fersialíticos, com florestas mesófilas de Quercus cerris (Carpinion betuli e florestas de Castanea sativa de origem antrópica; relevos alto-colinares com florestas de Ostryacarpinifolia ou Quercus pubescens, às vezes interrompidas por pequenas clareiras de pastagem, de origem secundária, de Brachypodium rupestre; leitos fluviais com florestas meso-higrófilas de Salixalba ou Alnus glutinosa; cimos e vertentes com pastagens de origem secundária de
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Bromus response to climate and projected changes with climate change [Chapter 9
Bethany A. Bradley; Caroline A. Curtis; Jeanne C. Chambers
2016-01-01
A prominent goal of invasive plant management is to prevent or reduce the spread of invasive species into uninvaded landscapes and regions. Monitoring and control efforts often rely on scientific knowledge of suitable habitat for the invasive species. However, rising temperatures and altered precipitation projected with climate change are likely to shift the...
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Is Pyrenophora semeniperda the cause of downy brome (Bromus tectorum) die-offs?
Owen W. Baughman; Susan E. Meyer
2013-01-01
Downy brome (cheatgrass) is a highly successful, exotic, winter annual invader in semi-arid western North America, forming near-monocultures across many landscapes. A frequent but poorly understood phenomenon in these heavily invaded areas is periodic 'die-off' or complete stand failure. The fungal pathogen Pyrenophora semeniperda is abundant in cheatgrass...
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Post-fire Downy Brome (Bromus tectorum) invasion at high elevation in Wyoming
The invasive annual grass downy brome is the most ubiquitous weed in sagebrush systems of western North America. The center of invasion has largely been the Great Basin region, but there is an increasing abundance and distribution in the Rocky Mountain States. We evaluated post-fire vegetation chang...
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Soil engineering facilitates Downy brome (Bromus tectorum L.) growth - A case study
Some exotic plants are able to engineer new host soils and engender characteristics that potentially increase their growth. We hypothesized that this positive feedback may be a facet in the competitiveness of the exotic annual grass downy brome. Using rhizotrons in the greenhouse, we compared the gr...
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Mapping and spatial-temporal modeling of Bromus tectorum invasion in central Utah
Jin, Zhenyu
Cheatgrass, or Downy Brome, is an exotic winter annual weed native to the Mediterranean region. Since its introduction to the U.S., it has become a significant weed and aggressive invader of sagebrush, pinion-juniper, and other shrub communities, where it can completely out-compete native grasses and shrubs. In this research, remotely sensed data combined with field collected data are used to investigate the distribution of the cheatgrass in Central Utah, to characterize the trend of the NDVI time-series of cheatgrass, and to construct a spatially explicit population-based model to simulate the spatial-temporal dynamics of the cheatgrass. This research proposes a method for mapping the canopy closure of invasive species using remotely sensed data acquired at different dates. Different invasive species have their own distinguished phenologies and the satellite images in different dates could be used to capture the phenology. The results of cheatgrass abundance prediction have a good fit with the field data for both linear regression and regression tree models, although the regression tree model has better performance than the linear regression model. To characterize the trend of NDVI time-series of cheatgrass, a novel smoothing algorithm named RMMEH is presented in this research to overcome some drawbacks of many other algorithms. By comparing the performance of RMMEH in smoothing a 16-day composite of the MODIS NDVI time-series with that of two other methods, which are the 4253EH, twice and the MVI, we have found that RMMEH not only keeps the original valid NDVI points, but also effectively removes the spurious spikes. The reconstructed NDVI time-series of different land covers are of higher quality and have smoother temporal trend. To simulate the spatial-temporal dynamics of cheatgrass, a spatially explicit population-based model is built applying remotely sensed data. The comparison between the model output and the ground truth of cheatgrass closure demonstrates that the model could successfully simulate the spatial-temporal dynamics of cheatgrass in a simple cheatgrass-dominant environment. The simulation of the functional response of different prescribed fire rates also shows that this model is helpful to answer management questions like, "What are the effects of prescribed fire to invasive species?" It demonstrates that a medium fire rate of 10% can successfully prevent cheatgrass invasion.
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Sage, R. F.; Bykova, O.; Coiner, H.
2010-12-01
One of the main effects of anthropogenic climate change will be widespread shifts in species distribution, with the common assumption that they will migrate to higher elevation and latitude. While this assumption is supported by migration patterns following climate warming in the past 20,000 years, it has not been rigorously evaluated in terms of physiological mechanism, despite the implication that migration in response to climate warming is controlled by some form of thermal adaptation. We have been evaluating the degree to which species range limits are controlled by physiological patterns of thermal tolerance in bioinvaders of North America. Bioinvaders presumably have few biotic controls over their distribution and thus are more likely to fully exploit their thermal niche. In cheatgrass (Bromus tectorum), the minimum lethal temperature in winter is -32C, which corresponds to the mean winter minimum temperature at its northern range limit. In red brome (Bromus rubens), the minimum lethal temperature is also near -32C, which is well below the minimum winter temperature near -20C that corresponds to its northern distribution limit. In kudzu (Pueraria lobata), the minimum lethal temperature is near -20C, which corresponds to the midwinter minimum at its northern distribution limit; however, overwintering kudzu tissues are insulated by soil and snow cover, and thus do not experience lethal temperatures at kudzu's northern range limit. These results demonstrate that some invasive species can exploit the potential range defined by their low temperature tolerance and thus can be predicted by mechanistic models to migrate to higher latitudes with moderation of winter cold. The distribution of other invaders such as kudzu and red brome are not controlled by tolerance of midwinter cold. Developing mechanistic models of their distributions, and how these might change with climate warming, will require extensive physiological study.
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The Effect of Heavy Metal Contaminated Soil on Growth and Development of Perennial Grasses
Directory of Open Access Journals (Sweden)
Żurek G.
2013-04-01
Full Text Available Contamination of agricultural land in Poland by heavy metals is not a general problem but is limited to industrial areas. In regions of long history of industrial emission, of elevated levels of lead, cadmium, zinc and other ions during coal and ore mining and processing, as for example in Silesia, about 10 % of agricultural land may be characterized by exceeded maximum residue limits for Cd, Pb, Cu, Ni and Zn ions. Since the maintenance of agricultural areas in those regions is important from an ecological standpoint, the alternative farming activities are needed. Perennial grass biomass production for energy purposes is currently the best solution for majority of agricultural areas not suitable for food production in Poland. Along with increasing knowledge on separation and utilization of heavy metals (HM during and after biomass processing, phytoremediation of polluted soils will become important and valuable. To detect the effect of soil HM ions concentration on growth and development of selected, tall growing and high biomass yielding perennial grass cultivars, the chlorophyll fluorescence parameters were registered. The elevated content of Pb, Cd and Zn ions in soil influenced on decrease of: minimal (Fo, maximal (Fm and variable (Fv fluorescence level as well as on total complementary area on a diagram of chlorophyll a fluorescence induction curve (Area. Based on detected parameters it was concluded, that the high level of HM ions in soils negatively affected the efficiency of photosynthesis. Therefore, plant growth, as well as development of generative shoots and finally the biomass yield were reduced in some cultivars. Among tested cultivars different reaction for HM ions in polluted soil were noted: from only slightly modified parameters of photosynthesis and unreduced yield (Elytrigia elongata cv. Bamar and Arrhenatherum elatius cv. Wiwena to significantly reduced Fo, Fv, Fm and biomass yield (Bromus carinathus cv. Broma and Bromus
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Ostoja, S.M.; Schupp, E.W.
2009-01-01
Aim The exotic annual cheatgrass (Bromus tectorum) is fast replacing sagebrush (Artemisia tridentata) communities throughout the Great Basin Desert and nearby regions in the Western United States, impacting native plant communities and altering fire regimes, which contributes to the long-term persistence of this weedy species. The effect of this conversion on native faunal communities remains largely unexamined. We assess the impact of conversion from native perennial to exotic annual plant communities on desert rodent communities. Location Wyoming big sagebrush shrublands and nearby sites previously converted to cheatgrass-dominated annual grasslands in the Great Basin Desert, Utah, USA. Methods At two sites in Tooele County, Utah, USA, we investigated with Sherman live trapping whether intact sagebrush vegetation and nearby converted Bromus tectorum-dominated vegetation differed in rodent abundance, diversity and community composition. Results Rodent abundance and species richness were considerably greater in sagebrush plots than in cheatgrass-dominated plots. Nine species were captured in sagebrush plots; five of these were also trapped in cheatgrass plots, all at lower abundances than in the sagebrush. In contrast, cheatgrass-dominated plots had no species that were not found in sagebrush. In addition, the site that had been converted to cheatgrass longer had lower abundances of rodents than the site more recently converted to cheatgrass-dominated plots. Despite large differences in abundances and species richness, Simpson's D diversity and Shannon-Wiener diversity and Brillouin evenness indices did not differ between sagebrush and cheatgrass-dominated plots. Main conclusions This survey of rodent communities in native sagebrush and in converted cheatgrass-dominated vegetation suggests that the abundances and community composition of rodents may be shifting, potentially at the larger spatial scale of the entire Great Basin, where cheatgrass continues to invade
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Mahelka, Václav; Kopecký, David
2010-06-01
Four accessions of hexaploid Elymus repens from its native Central European distribution area were analyzed using sequencing of multicopy (internal transcribed spacer, ITS) and single-copy (granule-bound starch synthase I, GBSSI) DNA in concert with genomic and fluorescent in situ hybridization (GISH and FISH) to disentangle its allopolyploid origin. Despite extensive ITS homogenization, nrDNA in E. repens allowed us to identify at least four distinct lineages. Apart from Pseudoroegneria and Hordeum, representing the major genome constituents, the presence of further unexpected alien genetic material, originating from species outside the Triticeae and close to Panicum (Paniceae) and Bromus (Bromeae), was revealed. GBSSI sequences provided information complementary to the ITS. Apart from Pseudoroegneria and Hordeum, two additional gene variants from within the Triticeae were discovered: One was Taeniatherum-like, but the other did not have a close relationship with any of the diploids sampled. GISH results were largely congruent with the sequence-based markers. GISH clearly confirmed Pseudoroegneria and Hordeum as major genome constituents and further showed the presence of a small chromosome segment corresponding to Panicum. It resided in the Hordeum subgenome and probably represents an old acquisition of a Hordeum progenitor. Spotty hybridization signals across all chromosomes after GISH with Taeniatherum and Bromus probes suggested that gene acquisition from these species is more likely due to common ancestry of the grasses or early introgression than to recent hybridization or allopolyploid origin of E. repens. Physical mapping of rDNA loci using FISH revealed that all rDNA loci except one minor were located on Pseudoroegneria-derived chromosomes, which suggests the loss of all Hordeum-derived loci but one. Because homogenization mechanisms seem to operate effectively among Pseudoroegneria-like copies in this species, incomplete ITS homogenization in our samples
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Energy Technology Data Exchange (ETDEWEB)
Hinds, W.T.
1975-01-01
An experiment to determine the fates of energy and carbon in cheatgrass (Bromus tectorum L.) was carried out on steep (40/sup 0/) north- and south-facing slopes on a small earth mound, using many small lysimeters to emulate swards of cheatgrass. Meteorological conditions and energy fluxes that were measured included air and soil temperatures, relative humidity, wind speed, incoming shortwave radiation, net all-wave radiation, heat flux to the soil, and evaporation and transpiration separately. The fate of photosynthetically fixed carbon during spring growth was determined by analysis of the plant tissues into mineral nutrients, crude protein, crude fat, crude fiber, and nitrogen-free extract (NFE) for roots, shoots, and seeds separately. (auth)
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Provisional catalogue of the flora of San Ignacio de Huinay, Chile
Directory of Open Access Journals (Sweden)
Ramón Morales
2016-09-01
Full Text Available Contribution to the vascular plants flora of San Ignacio de Huinay natural reserve, Comau fiord, Región de los Lagos, Chile. To date, 262 species with their herbaria sheets stored in 5 different American and European herbaria (CONC, M, MA, and SGO and that of Huinay, are known in the territory. In this work some first new records for the South Cone are included, such as Potentilla anglica, Plantago media, and Mentha x rotundifolia. Furthermore, some of the records are new for the Flora of Chile, such as Juncus burkartii, only known from Argentina. Other species very scarcely cited in Chile, such as Solanum nigrum and Bromus squarrosus, are also included.
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Ozone sensitivity of plants in natural communities
Energy Technology Data Exchange (ETDEWEB)
Treshow, M; Stewart, D
1973-07-01
Field fumigation studies conducted in grassland, oak, aspen, and conifer, communities established the injury threshold of prevalent plant species to ozone. Several important species, including Bromus tectorum, Quercus gambelii, and Populus tremuloides, were injured by a single 2-hours exposure to 15 pphM ozone. Over half the perennial forbs and woody species studied were visibly injured at concentrations of 30 pphM ozone or less. It is postulated that lower concentrations at prolonged or repeated exposures to ozone may impair growth and affect community vigor and stability. Continued exposure of natural plant communities to ozone is expected to initiate major shifts in the plant composition of communities. 10 references, 4 figures, 1 table.
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Flora of the city of Podgorica, Montenegro: Taxonomic analysis
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Stešević Danijela
2008-01-01
Full Text Available In this paper we present the taxonomic segment of a floristic study undertaken in the city of Podgorica in the period of 2002-2007. The check-list of spontaneously growing vascular plants includes 1227 species and subspecies belonging to 545 genera and 118 families. The dominant families are Poaceae (11.7%, asteraceae (11.2% and Fabaceae (9.2%. The most abundant genera are Trifolium (2.1%, Euphorbia (1.5%, Carex (1.5%, Bromus (1.3% and Vicia (1.2%. Analysis of the flora of Podgorica in comparison with some other european cities showed that the flora of Podgorica is most similar to that of Rome (Q/S= 0,7.
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Directory of Open Access Journals (Sweden)
AT. Nakamura
2010-05-01
Full Text Available Anther and pollen development were studied in Olyra humilis Nees, Sucrea monophylla Soderstr, (Bambusoideae, Axonopus aureus P. Beauv., Paspalum polyphyllum Nees ex Trin. (Panicoideae, Eragrostis solida Nees, and Chloris elata Desv. (Chloridoideae. The objective of this study was to characterise, embryologically, these species of subfamilies which are considered basal, intermediate and derivate, respectively. The species are similar to each other and to other Poaceae. They present the following characters: tetrasporangiate anthers; monocotyledonous-type anther wall development, endothecium showing annular thickenings, secretory tapetum; successive microsporogenesis; isobilateral tetrads; spheroidal, tricellular, monoporate pollen grains with annulus and operculum. Nevertheless, the exine patterns of the species studied are distinct. Olyra humilis and Sucrea monophylla (Bambusoideae show a granulose pattern, whereas in the other species, it is insular. In addition, Axonopus aureus and Paspalum polyphyllum (Panicoideae have a compactly insular spinule pattern, while Chloris elata and Eragrostis solida (Chloridoideae show a sparsely insular spinule pattern. The exine ornamentation may be considered an important feature at the infrafamiliar level.O desenvolvimento da antera e do grão de pólen de Olyra humilis Nees, Sucrea monophylla Soderstr. (Bambusoideae, Axonopus aureus P. Beauv., Paspalum polyphyllum Nees ex Trin. (Panicoideae, Eragrostis solida Nees and Chloris elata Desv. (Chloridoideae foi estudado visando caracterizar embriologicamente essas espécies de subfamílias consideradas basal, intermediária e derivada, respectivamente. As espécies são similares entre si e entre as demais Poaceae. Apresentam os seguintes caracteres: anteras tetrasporangiadas; desenvolvimento da parede da antera do tipo monocotiledôneo, endotécio com espessamento de parede anelar, tapete secretor; microsporogênese sucessiva; tétrades isobilaterais; grãos de
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International Nuclear Information System (INIS)
Batty, Lesley C.; Younger, Paul L.
2004-01-01
The abandoned mine of Shilbottle Colliery, Northumberland, UK is an example of acidic spoil heap discharge that contains elevated levels of many metals. Aerobic wetlands planted with the common reed, Phragmites australis, were constructed at the site to treat surface runoff from the spoil heap. The presence of a perched water table within the spoil heap resulted in the lower wetlands receiving acidic metal contaminated water from within the spoil heap while the upper wetland receives alkaline, uncontaminated surface runoff from the revegetated spoil. This unique situation enabled the comparison of metal uptake and growth of plants used in treatment schemes in two cognate wetlands. Results indicated a significant difference in plant growth between the two wetlands in terms of shoot height and seed production. Analyses of metal and nutrient concentrations within plant tissues provided the basis for three hypotheses to explain these differences: (i) the toxic effects of high levels of metals in shoot tissues (ii) the inhibition of Ca (an essential nutrient) uptake by the presence of metals and H + ions, and (iii) low concentrations of bioavailable nitrogen sources resulting in nitrogen deficiency. This has important implications for the engineering of constructed wetlands in terms of the potential success of plant establishment and vegetation development
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Relaciones suelo-planta-herbívoro en un sistema pastoral de montaña
Directory of Open Access Journals (Sweden)
Alonso, I.
1996-12-01
Full Text Available The soil characteristics of six communities with pastoral interest in León mountain (Spain and the Ca, Cu, Fe, Mg, N, K and Na contents of soils and vegetation were analysed in relation with the nutritional characteristics of herbivores' diet. The communities were named after the most representative species: Nardus stricta, Bromus erectus. Genista florida. Erica australis. Genista occidentalis and Calluna vulgaris. Soils showed in general good conditions for vegetal growth. There were no relationships between soil and plants mineral contents. Ca and Cu were deficient in some moments during the stay of the animals in the mountain. Mineral concentrations in vegetation communities varied seasonally due to maturity processes and physiological changes in plants, depending on the kind of plant and the microenvironment where they grew.
[es] Se analizaron las características edáficas de seis comunidades de interés pastoral.en la montaña de León denominadas en función de la especie más representativa (Nardus stricta, Bromus erectus, Genista florida. Erica australis, Genista occidentalis, Calluna vulgaris, así como las concentraciones minerales de Ca, Cu, Fe, Mg, N, Ky Na en suelos y pastos por su influencia sobre las características nutritivas de la dieta de los herbívoros. Según los resultados obtenidos, los suelos presentaron en general unas buenas condiciones para el desarrollo vegetal. No se apreció ninguna relación entre la concentración de minerales en suelos y plantas. Las cantidades de Ca y Cu presentes en la vegetación fueron insuficientes para el mantenimiento de los herbívoros domésticos al menos durante parte de su estancia en el puerto. Las concentraciones minerales en la vegetación sufrieron variaciones estacionales debido a procesos de madurez y cambios fisiológicos, en mayor o menor medida según el tipo de planta y el ambiente en que se encuentre. [de] Die Bodeneigenschaften von sechs -
Weather-induced variability of cesium 137 content in overground part of automorphic soil plants
International Nuclear Information System (INIS)
Eliashevich, H.V.
2000-01-01
Daily variability of specific cesium 137 content in plants (12 species) from 30-km zone of Chernobyl NPP in summer time under the influence of climatic factors is shown. The rise of residual solar radiation (exceeding 2 MJ/m 2 in a day) and average diurnal temperature over 10 - 15 degrees centigrade (for different species) induced decrease in activity of overground phyto mass while precipitation takes opposite effect. A threshold and non-threshold type of cesium 137 accumulation in plants was recorded at higher daily fall-out. Critical sum of diurnal precipitation for the latter case in 5 species (Agropyron repens (L.) P.B., Bromus inermis Leyss., Origanum vulgare L., Festuca arundinacea Shreb., Acer plata noides L.) is in the range of 20 - 25 mm
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Osmotic and ionic effects of NaCl and Na2SO4 salinity on Phragmites australis
DEFF Research Database (Denmark)
Pagter, Majken; Bragato, Claudia; Malagoli, Mario
2009-01-01
Osmotic and ion-specific effects of NaCl and Na2SO4 on Phragmites australis (Cav.) Trin ex. Steud. were investigated in a laboratory experiment by examining effects of iso-osmotic solutions of NaCl and Na2SO4 on growth, osmolality of cell sap, proline content, elemental composition and gas exchange....... Plants were supplied with a control standard nutrient solution (Ψ = -0.09 MPa) or solutions of NaCl or Na2SO4 at water potentials of -0.50, -1.09 or -1.74 MPa. Salt treatments increased root concentrations of Na and S or Cl, whereas P. australis had efficient mechanisms for exclusion of Na and S...... and partly Cl ions from the leaves. Incomplete exclusion of Cl from the leaves may affect aboveground biomass production, which was significantly more reduced by NaCl than Na2SO4. Stomatal conductance was negatively influenced by decreasing water potentials caused by NaCl or Na2SO4, implying that a non...
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EFISIENSI PEMBERIAN PERUPUK TERHADAP SERAPAN LIMBAH CAIR INDUSTRI KARET
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Deddy Dharmaji
2016-06-01
Full Text Available This research was aimed to analyze the ability of perupuk (Phragmites karka Trin in reducing the element of rubber industrial liquid waste polluters on the scale of the laboratory. The method used was the method of survey. The data from laboratory test were tabulated and analyzed descriptively and the level of efficiency was calculated. Referring to South Kalimantan Governor Regulation Number 36 in 2008, the results showed that, TSS parameters started to be effectively reduced on day 10 (T 1 with close to 84,33 mg/l (32.53%, BOD5 started to be effectively reduced on day 20 (T 2 with close to 24.00 mg/l (99,29%, and COD started to be effectively reduced on day 20 (T 2 with close to 44,65 mg/l (98,90% due to the levels were already below the value of the Quality Standard Liquid Waste (QSLW. Generally, time retention was best accomplished on day 30 (T 3 in reducing liquid waste rubber industry.
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Dansk oversættelse af MiDAS, et redskab til assessment af musikterapi for personer med demens
DEFF Research Database (Denmark)
Ridder, Hanne Mette Ochsner; Lykkegaard, Chris; McDermott, Orii
2018-01-01
Music in Dementia Assessment Scales, MiDAS, er udviklet til at vurdere ændringer i trivsel hos borgere med demens som har deltaget i musikterapi. Målingen udføres af 1) personale før og efter musikterapien for at vurdere om der er en indflydelse i hverdagssituationer efterfølgende, eller af 2......) musikterapeuten umiddelbart efter sessionen for at vurdere forandringer i selve sessionen. Der har været stor interesse for at anvende MiDAS i flere Europæiske lande, herunder Danmark. Derfor undersøgte udviklerne af MiDAS hvilke procedurer der anvendes til oversættelse og kulturel tilpasning af...... assessmentredskaber, og anbefalede på den baggrund en ti-trins procedure. Vi anvendte denne procedure til oversættelsen af MiDAS og således udviklingen af den danske MiDAS-DK. Den danske version af MiDAS er afprøvet af mere end 20 fagpersoner på baggrund af 296 udfyldte MiDAS-skemaer. Målet med artiklen er...
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Degradation of Total Petroleum Hydrocarbon in Phytoremediation Using Terrestrial Plants
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Mushrifah Idris
2014-06-01
Full Text Available This study focused on the total petroleum hydrocarbon (TPH degradation in phytoremediation of spiked diesel in sand. The diesel was added to the sand that was planted with terrestrial plants. Four selected terrestrial plants used were Paspalum vaginatum Sw, Paspalums crobiculatum L. varbispicatum Hack, Eragrotis atrovirens (Desf. Trin. ex Steud and Cayratia trifolia (L. Domin since all the plants could survive at a hydrocarbon petroleum contaminated site in Malaysia. The samplings were carried out on Day 0, 7, 14, 28, 42 and 72. The analysis of the TPH was conducted by extracting the spiked sand using ultrasonic extraction. The determination of the TPH concentration in the sand was performed using GC-FID. The degradation of TPH depends on the plant species and time of exposure. The highest percentage degradation by P. vaginatum, P. scrobiculatum, E. atrovirens and C. trifolia were 91.9, 74.0, 68.9 and 62.9%, respectively. In conclusion, the ability to degrade TPH by plants were P. vaginatum > P. scrobiculatum > E. atrovirens> C. trifolia.
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Grassby, Terri; Jay, Andrew J; Merali, Zara; Parker, Mary L; Parr, Adrian J; Faulds, Craig B; Waldron, Keith W
2013-10-09
Chinese water chestnut (Eleocharis dulcis (Burman f.) Trin ex Henschel) is a corm consumed globally in Oriental-style cuisine. The corm consists of three main tissues, the epidermis, subepidermis, and parenchyma; the cell walls of which were analyzed for sugar, phenolic, and lignin content. Sugar content, measured by gas chromatography, was higher in the parenchyma cell walls (931 μg/mg) than in the subepidermis (775 μg/mg) or epidermis (685 μg/mg). The alkali-extractable phenolic content, measured by high-performance liquid chromatography, was greater in the epidermal (32.4 μg/mg) and subepidermal cell walls (21.7 μg/mg) than in the cell walls of the parenchyma (12.3 μg/mg). The proportion of diferulic acids was higher in the parenchyma. The Klason lignin content of epidermal and subepidermal cell walls was ~15%. Methylation analysis of Chinese water chestnut cell-wall polysaccharides identified xyloglucan as the predominant hemicellulose in the parenchyma for the first time, and also a significant pectin component, similar to other nongraminaceous monocots.
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Ashton, Isabel; Symstad, Amy J.; Davis, Christopher; Swanson, Daniel J.
2016-01-01
Two Eurasian invasive annual brome grasses, cheatgrass (Bromus tectorum) and Japanese brome (Bromus japonicus), are well known for their impact in steppe ecosystems of the western United States where these grasses have altered fire regimes, reduced native plant diversity and abundance, and degraded wildlife habitat. Annual bromes are also abundant in the grasslands of the Northern Great Plains (NGP), but their impact and ecology are not as well studied. It is unclear whether the lessons learned from the steppe will translate to the mixed-grass prairie where native plant species are adapted to frequent fires and grazing. Developing a successful annual brome management strategy for National Park Service units and other NGP grasslands requires better understanding of (1) the impact of annual bromes on grassland condition; (2) the dynamics of these species through space and time; and (3) the relative importance of environmental factors within and outside managers' control for these spatiotemporal dynamics. Here, we use vegetation monitoring data collected from 1998 to 2015 in 295 sites to relate spatiotemporal variability of annual brome grasses to grassland composition, weather, physical environmental characteristics, and ecological processes (grazing and fire). Concern about the impact of these species in NGP grasslands is warranted, as we found a decline in native species richness with increasing annual brome cover. Annual brome cover generally increased over the time of monitoring but also displayed a 3- to 5-yr cycle of reduction and resurgence. Relative cover of annual bromes in the monitored areas was best predicted by park unit, weather, extant plant community, slope grade, soil composition, and fire history. We found no evidence that grazing reduced annual brome cover, but this may be due to the relatively low grazing pressure in our study. By understanding the consequences and patterns of annual brome invasion, we will be better able to preserve and restore
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Directory of Open Access Journals (Sweden)
Maristela de Oliveira Bauer
2005-12-01
Full Text Available Objetivou-se, com este trabalho, verificar, pela técnica micro-histológica, diferenças entre espécies forrageiras quanto ao percentual de fragmentos identificáveis, em função do processo digestivo e da época do ano. Lâminas foliares frescas recém-expandidas, correspondentes à última e à penúltima posição no perfilho, das espécies Melinis minutiflora Pal. de Beauv (capim-gordura, Hyparrhenia rufa (Nees Stapf. (capim-jaraguá, Brachiaria decumbens Stapf. (capim-braquiária, Imperata brasiliensis Trin. (capim-sapé, de Medicago sativa L. (alfafa e de Schinus terebenthifolius Raddi (aroeira, amostradas nos períodos chuvoso e seco, foram digeridas in vitro e preparadas de acordo com a técnica micro-histológica. Observou-se que as espécies apresentaram diferenças marcantes na porcentagem de fragmentos identificáveis e que a digestão alterou estas porcentagens em torno de 10 %; que o período de amostragem não influenciou a porcentagem de fragmentos identificáveis para a maioria das espécies; que a presença de pigmentos e a adesão da epiderme às células dos tecidos internos da folha prejudicaram a identificação dos fragmentos; e que a digestão melhorou a visualização dos fragmentos dos capins sapé e jaraguá e da aroeira, mas prejudicou a do capim-braquiária e, principalmente, a da alfafa.The objetive of this study was to verify differences among forages species in relation to the percentage of identifiable fragment as affected by the digestion process and season. Fresh last expanded leaf lamina samples of the species Melinis minutiflora Pal. de Beauv (Molassesgrass, Hyparrhenia rufa (Nees Stapf. (Jaraguagrass, Brachiaria decumbens Stapf. (Signalgrass, Imperata brasilienses Trin. (Sapegrass, and foliar laminas of Medicago sativa L. (Alfalfa and Schinus terebenthifolius Raddi (Aroeira, sampled in the rainy and dry seasons, were digested in vitro and prepared according to the microhistological technique. The
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Directory of Open Access Journals (Sweden)
Héctor Andrés Vargas
2015-12-01
Full Text Available ABSTRACT Elachista synethes was recently recognized as an alien species in northern Chile, where its larvae mine the rescue grass Bromus catharticus (Poaceae. In order to provide the necessary information to allow field detection of E. synethes during early ontogeny, we conducted a morphological reappraisal of the immature stages of this leaf-miner moth, based on light and scanning electron microscopy, including the first descriptions of the egg and the first-instar larva. This is the first report of the existence of an apodal early larva for a species of Elachista Treitschke. The legs and prolegs are absent in the first two instars, but are well developed in the last two. Additional observations on the life history are also provided, including a description of the mine.
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UNMANNED AERIAL VEHICLE (UAV) HYPERSPECTRAL REMOTE SENSING FOR DRYLAND VEGETATION MONITORING
Energy Technology Data Exchange (ETDEWEB)
Nancy F. Glenn; Jessica J. Mitchell; Matthew O. Anderson; Ryan C. Hruska
2012-06-01
UAV-based hyperspectral remote sensing capabilities developed by the Idaho National Lab and Idaho State University, Boise Center Aerospace Lab, were recently tested via demonstration flights that explored the influence of altitude on geometric error, image mosaicking, and dryland vegetation classification. The test flights successfully acquired usable flightline data capable of supporting classifiable composite images. Unsupervised classification results support vegetation management objectives that rely on mapping shrub cover and distribution patterns. Overall, supervised classifications performed poorly despite spectral separability in the image-derived endmember pixels. Future mapping efforts that leverage ground reference data, ultra-high spatial resolution photos and time series analysis should be able to effectively distinguish native grasses such as Sandberg bluegrass (Poa secunda), from invasives such as burr buttercup (Ranunculus testiculatus) and cheatgrass (Bromus tectorum).
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Enhanced fire-related traits may contribute to the invasiveness of Downy Brome (Bromus tectorum)
Although several invasive species have induced changes to the fire regime of invaded ecosystems, potential intraspecific shifts in fire-related traits that might enhance their invasion success, have never been addressed. We assumed that traits conferring persistence and competitiveness in post-fire ...
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Composted manure application promotes long-term invasion of semi-arid rangeland by Bromus tectorum
Composted organic matter derived from sewage treatment facilities or livestock manure from feedlots is often applied to rangelands of western North America to increase soil fertility, forage production, forage quality, and soil carbon (C) storage. This practice can have a number of undesirable side ...
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Suzanne M. Owen; Carolyn Hull Sieg; Catherine A. Gehring
2011-01-01
Rehabilitation of downy brome-infested shrublands is challenging once this invasive grass dominates native communities. The effectiveness of imazapic herbicide in reducing downy brome cover has been variable, and there is uncertainty about the impacts of imazapic on native species. We used a before-after-control-impact (BACI) field experiment and greenhouse studies to...
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Liquid-Liquid extraction of sulfuric acid using tri-n-dodecylamine/kerosene
International Nuclear Information System (INIS)
Stas, J.
2009-01-01
The extraction of sulfuric acid has been investigated by trin- dodecylamine (over line TDA) in kerosene in the presence of octanol- 1 as modifier. The effect of octanol-1 has been studied on the equilibrium constant of (TDAH) 2 SO 4 and TDAHHSO 4 formation in the concentration range from 5 to 25% v/v and within the temperature range from 25 to 50 centigrade degree. The equilibrium constants (K 1 and K 2 , at 25 centigrade degree), the enthalpy (ΔH 0 1 , ΔH 0 2 ) and the entropy (ΔS 0 1 , ΔS 0 2 ) changes were calculated for two extraction reactions of sulfuric acid by tri-n-dodecylamine containing 10% octanol-1 and they were found to be 10 9 .642 l 4 /mol 4 , 10 - 0.899 l/mol, -99.11, -22.17 kJ/mol, -0.149, -0.063 kJ/mol.K, respectively. The two reactions are: 2/overline TDA +2 H + +SO 4 2 -/rightleftarrows K 1 /overline (TDAH) 2 SO 4 and /overline (TDHA) 2 SO 4 H + +HSO 4 - /rightleftarrows K 2 2/overline TDAHHSO 4 . (author)
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Wang, Qi; Bao, Yuying; Liu, Xiaowei; Du, Guoxin
2014-10-01
Temporal and spatial patterns of arbuscular mycorrhizal fungi (AMF) and glomalin and soil enzyme activities were investigated in different managed semiarid steppes located in Inner Mongolia, North China. Soils were sampled in a depth up to 30 cm from non-grazed, overgrazed, and naturally restored steppes from June to September. Roots of Leymus chinense (Trin.) Tzvel. and Stipagrandis P. Smirn. were also collected over the same period. Results showed that overgrazing significantly decreased the total mycorrhizal colonization of S. grandis; total colonization of L. chinensis roots was not significantly different in the three managed steppes. Nineteen AMF species belonging to six genera were isolated. Funneliformis and Glomus were dominant genera in all three steppes. Spore density and species richness were mainly influenced by an interaction between plant growth stage and management system (P soil depth. AMF species richness was significantly positively correlated with soil acid phosphatase activity, alkaline phosphatase activity, and two Bradford-reactive soil protein (BRSP) fractions (P soil glomalin and phosphatase activity in different managed semiarid steppes. Based on these observations, AMF communities could be useful indicators for evaluating soil quality and function of semiarid grassland ecosystems.
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Zheng, S; Wang, C; Shen, Z; Quan, Y; Liu, X
2015-01-01
This study presents an efficient heavy metal (HM) control method in HM-contaminated wetlands with varied soil moisture levels through the introduction of extrinsic arbuscular mycorrhizal fungi (AMF) into natural wetland soil containing indigenous AMF species. A pot culture experiment was designed to determine the effect of two soil water contents (5-8% and 25-30%), five extrinsic AMF inoculants (Glomus mosseae, G. clarum, G. claroideum, G. etunicatum, and G. intraradices), and HM contamination on root colonization, plant growth, and element uptake of common reed (Phragmites australis (Cav.) Trin. ex Steudel) plantlets in wetland soils. This study showed the prevalence of mycorrhizae in the roots of all P. australis plantlets, regardless of extrinsic AMF inoculations, varied soil moisture or HM levels. It seems that different extrinsic AMF inoculations effectively lowered HM concentrations in the aboveground tissues of P. australis at two soil moisture levels. However, metal species, metal concentrations, and soil moisture should also be very important factors influencing the elemental uptake performance of plants in wetland ecosystems. Besides, the soil moisture level significantly influenced plant growth (including height, and shoot and root dry weight (DW)), and extrinsic AMF inoculations differently affected shoot DW.
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International Nuclear Information System (INIS)
Ganesh, S.; Velavendan, P.; Pandey, N.K.; Ahmed, M.K.; Kamachi Mudali, U.; Natarajan, R.
2012-01-01
A spectrophotometric method is developed for the determination of dissolved tri-n butyl phosphate (TBP) in aqueous streams of Purex process used in nuclear fuel reprocessing. The method is based on the formation of phosphomolybdate with added ammonium molybdate followed by reduction with hydrazine sulphate in acid medium. Orthophosphate and molybdate ions combine in acidic solution to give molybdophosphoric (phosphomolybdic) acid, which upon selective reduction (with hydrazinium sulphate) produces a blue colour, due to molybdenum blue. The intensity of blue colour is proportional to the amount of phosphate. If the acidity at the time of reduction is 0.5 M in sulphuric acid and hydrazinium sulphate is the reductant, the resulting blue complex exhibits maximum absorption at 810-840 nm. The system obeys Lambert-Beer's law at 830 nm in the concentration range of 0.1-1.0 μg/mol of phosphate. Molar Absorptivity was determined to be 3.1 x 10 4 L mol -1 cm -1 at 830 nm. The results obtained are reproducible with standard deviation of 1 % and relative error less than 2 % and are in good agreement with those obtained by ion chromatographic technique. (author)
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International Nuclear Information System (INIS)
Fan Guolan; Cui Zhaojie; Liu Jing
2009-01-01
To investigate the interspecies variance of Dioxin-like polychlorinated biphenyls (DL-PCBs) in the plants from modern Yellow River delta, the concentrations of 12 DL-PCBs congeners were examined in five plant species and their associated soils. The DL-PCBs concentrations in plants (2.32-287.60 ng/kg dry weight) were low compared to most published literature, and the concentrations and ratios of DL-PCBs congeners in plants varied greatly among species. The properties of plants and PCBs were then studied to explore the factors affecting the interspecies variance of DL-PCBs accumulation. The plants with the smallest variance of morphological and physiological characteristics (Imperata cylindrical var. Major and Phragmites australis (Cav.) Trin. ex Steud) had the most similar accumulation patterns of DL-PCBs among the species tested. As the octanol-air partitioning coefficient (K oa ) of the DL-PCBs increased, interspecies variance decreased on the whole plant level. Interestingly, the correlation between the DL-PCBs concentrations in plants and log K oa of congeners was found to be significant for annual plants, but for perennial plants it was not significant. Thus the patterns of uptake of DL-PCBs are different between annual and perennial plants
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Energy Technology Data Exchange (ETDEWEB)
Guolan, Fan [Environmental Research Institute, Shandong University, Jinan, Shandong Province 250100 (China); Cui Zhaojie [School of Environmental Science and Engineering, Shandong University, Jinan, Shandong Province 250100 (China)], E-mail: cuizj@sdu.edu.cn; Jing, Liu [School of City Planning and Environmental Engineering, Shandong Jianzhu University, Jinan, Shandong Province 250101 (China)
2009-04-30
To investigate the interspecies variance of Dioxin-like polychlorinated biphenyls (DL-PCBs) in the plants from modern Yellow River delta, the concentrations of 12 DL-PCBs congeners were examined in five plant species and their associated soils. The DL-PCBs concentrations in plants (2.32-287.60 ng/kg dry weight) were low compared to most published literature, and the concentrations and ratios of DL-PCBs congeners in plants varied greatly among species. The properties of plants and PCBs were then studied to explore the factors affecting the interspecies variance of DL-PCBs accumulation. The plants with the smallest variance of morphological and physiological characteristics (Imperata cylindrical var. Major and Phragmites australis (Cav.) Trin. ex Steud) had the most similar accumulation patterns of DL-PCBs among the species tested. As the octanol-air partitioning coefficient (K{sub oa}) of the DL-PCBs increased, interspecies variance decreased on the whole plant level. Interestingly, the correlation between the DL-PCBs concentrations in plants and log K{sub oa} of congeners was found to be significant for annual plants, but for perennial plants it was not significant. Thus the patterns of uptake of DL-PCBs are different between annual and perennial plants.
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International Nuclear Information System (INIS)
Cataldo, D.A.
1979-03-01
Studies were undertaken to determine the plant availability of 134 Cs and 85 Sr amended to Rupert surface soil and an associated subsoil. Concentration ratios for cheatgrass (Bromus tectorum) and tumbleweed (Salsola kali) grown on 134 Cs amended Rupert soil were 0.15 and 0.28, respectively; values for amended subsoils were 0.074 and 0.13, respectively. Rupert surface soil and subsoil amended with 85 Sr gave concentration ratios of 15 and 7, respectively, for both tumbleweed and cheatgrass. While pot size (1 vs 4 kg) had a market effect on concentration ratios, values for greenhouses and growth chamber grown plants were generally similar. Aging of both Rupert surface soil and subsoils for 1 to 30 days prior to planting had a pronounced effect on the availability of 134 Cs for uptake by plants, but no effect on 85 Sr uptake
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Salo, L.F.
2004-01-01
Red brome is a Mediterranean winter annual grass that has invaded south-western USA deserts. Unlike native annuals, it does not maintain a soil seed bank, but exhibits early and uniform germination. Above-average winter precipitation in these regions allows red brome to reach high density and biomass. These are time for concern, as large numbers of easily dispersed seeds increase the likelihood that it may spread into new areas. However, early and uniform germination can also lead to population crashes when drought precludes seed production. Winter droughts dramatically reduce densities of red brome, but provide opportunities for management of this exotic grass.
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Negative impacts of invasive plants on conservation of sensitive desert wildlife
Drake, K. Kristina; Bowen, Lizabeth; Nussear, Kenneth E.; Esque, Todd C.; Berger, Andrew J.; Custer, Nathan; Waters, Shannon C.; Johnson, Jay D.; Miles, A. Keith; Lewison, Rebecca L.
2016-01-01
Habitat disturbance from development, resource extraction, off-road vehicle use, and energy development ranks highly among threats to desert systems worldwide. In the Mojave Desert, United States, these disturbances have promoted the establishment of nonnative plants, so that native grasses and forbs are now intermixed with, or have been replaced by invasive, nonnative Mediterranean grasses. This shift in plant composition has altered food availability for Mojave Desert tortoises (Gopherus agassizii), a federally listed species. We hypothesized that this change in forage would negatively influence the physiological ecology, immune competence, and health of neonatal and yearling tortoises. To test this, we monitored the effects of diet on growth, body condition, immunological responses (measured by gene transcription), and survival for 100 captive Mojave tortoises. Tortoises were assigned to one of five diets: native forbs, native grass, invasive grass, and native forbs combined with either the native or invasive grass. Tortoises eating native forbs had better body condition and immune functions, grew more, and had higher survival rates (>95%) than tortoises consuming any other diet. At the end of the experiment, 32% of individuals fed only native grass and 37% fed only invasive grass were found dead or removed from the experiment due to poor body conditions. In contrast, all tortoises fed either the native forb or combined native forb and native grass diets survived and were in good condition. Health and body condition quickly declined for tortoises fed only the native grass (Festuca octoflora) or invasive grass (Bromus rubens) with notable loss of fat and muscle mass and increased muscular atrophy. Bromus rubens seeds were found embedded in the oral mucosa and tongue in most individuals eating that diet, which led to mucosal inflammation. Genes indicative of physiological, immune, and metabolic functions were transcribed at lower levels for individuals fed B
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Fire Impacts on the Mojave Desert Ecosystem: Literature Review
Energy Technology Data Exchange (ETDEWEB)
Fenstermaker Lynn
2012-01-01
The Nevada National Security Site (NNSS) is located within the Mojave Desert, which is the driest region in North America. Precipitation on the NNSS varies from an annual average of 130 millimeters (mm; 5.1 inches) with a minimum of 47 mm (1.9 inches) and maximum of 328 mm (12.9 inches) over the past 15 year period to an annual average of 205 mm (8.1 inches) with an annual minimum of 89 mm (3.5 inches) and maximum of 391 mm (15.4 inches) for the same time period; for a Frenchman Flat location at 970 meters (m; 3182 feet) and a Pahute Mesa location at 1986 m (6516 feet), respectively. The combination of aridity and temperature extremes has resulted in sparsely vegetated basins (desert shrub plant communities) to moderately vegetated mountains (mixed coniferous forest plant communities); both plant density and precipitation increase with increasing elevation. Whereas some plant communities have evolved under fire regimes and are dependent upon fire for seed germination, plant communities within the Mojave Desert are not dependent on a fire regime and therefore are highly impacted by fire (Brown and Minnich, 1986; Brooks, 1999). As noted by Johansen (2003) natural range fires are not prevalent in the Mojave and Sonoran Deserts because there is not enough vegetation present (too many shrub interspaces) to sustain a fire. Fire research and hence publications addressing fires in the Southwestern United States (U.S.) have therefore focused on forest, shrub-steppe and grassland fires caused by both natural and anthropogenic ignition sources. In the last few decades, however, invasion of mid-elevation shrublands by non-native Bromus madritensis ssp. rubens and Bromus tectorum (Hunter, 1991) have been highly correlated with increased fire frequency (Brooks and Berry, 2006; Brooks and Matchett, 2006). Coupled with the impact of climate change, which has already been shown to be playing a role in increased forest fires (Westerling et al., 2006), it is likely that the fire
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Radiation and temperature influence on forage grasses yield
International Nuclear Information System (INIS)
Vadell, J.; Medrano, H.
1986-01-01
Biomass production has been studied in forage plants, as well as the temperature and radiation effects on plant growth. Four cultivars of grasses: Lolium multiflorum var westerwoldicum cv Promenade, Lolium perenne cvs Combi and Compas and Bromus inermis were growing as microswards in a growth chamber with constant temperature and outdoors. A field assay was done also with the same cultivars. L. multiflorum was the highest productive genotype anywhere showing also more active growth at low temperatures. Total production showed significant differences among genotypes. It was also a clear correspondence among microswards and field productions. Highest efficiency values (in % of PAR accumulated as dry matter) was obtained in 6th cut (April) achieving to 5.18 % in L. multiflorum. Biomass production variations through the growth period show a low correlation with <
> and very high correlation with total irradiation received by the sward between consecutive cuts [es -
International Nuclear Information System (INIS)
Auge, R.M.; Gealy, D.R.; Ogg, A.G.; Franceschi, V.R.
1987-01-01
Developing and mature leaves of winter wheat (Triticum aestivum L. var. Daws) and the weed species downy brome (Bromus tectorum L.) were subjected to 10 mM (foliar application) and 1 mM (root application) herbicide solutions. Glyphosate (N-(phosphonomethyl) glycine) and atrazine (2-chloro-4-(ethyl-amino)-6-(isopropylamino)-s-triazine) were prepared in a carrier composed of 5% soybean oil concentrate, 35% acetone and 60% water. Penetration experiments with 3 H-labelled herbicides assessed what percentage of herbicide entered leaves, and microautoradiography was used to determine qualitatively how much herbicide was present in the sections viewed with TEM. Tissue was excised at 4, 18, 62 and 200 hours, and then either freeze-substituted or fixed chemically. Ultrastructural effects of each herbicide on chloroplasts from leaves of newly-germinated seedlings and of well-tillered plants are depicted and discussed. Temporal differences in response of chloroplasts to each herbicide are noted
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Severson, R.C.; Gough, L.P.
1984-01-01
Plant uptake of Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn from mine soils was assessed using alfalfa Medicago sativa, sainfoin Onobrychis viciaefolia, smooth brome Bromus inermis, crested wheatgrass Agropyron cristatum, slender wheatgrass A. trachycaulum and intermediate wheatgrass A. intermedium; mine soil (cover-soil and spoil material) samples were collected from rehabilitated areas of 11 western US surface-coal mines in North Dakota, Montana, Wyoming and Colorado. Correlations between metals in plants and DTPA-extractable metals from mine soils were generally not statistically significant and showed no consistent patterns for a single metal or for a single plant species. Metal uptake by plants, relative to amounts in DTPA extracts of mine soil, was positively related to mine soil organic matter content or negatively related to mine soil pH. DTPA-extractable metal levels were significantly correlated with mine soil pH and organic-matter content.-from Authors
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The 'Big bang' in the Early Iron Age
Directory of Open Access Journals (Sweden)
Medović Aleksandar
2010-01-01
Full Text Available The Early Iron Age granaries of Tell Gradina upon Bosut exploded in a fire inferno in the 8th century B.C. The result of this catastrophe is 2-5 cm thick layer with mixed carbonized seeds and fruits. Recently, eight samples were taken from Gradina's profile for archaeobotanical analysis. The goal was to obtain basic information on land use and on major crops and weeds of that period. The most abundant were cereals, followed by millets, pulses and oil/fibre plants. The dominant cereals were einkorn (Triticum monococcum and hulled barley (Hordeum vulgare vulgare. Broomcorn millet (Panicum miliaceum was also very important. Pulses were represented with six and oil/fibre plants with three species. Among weeds and ruderals, most common are rye brome (Bromus secalinus, fat hen (Chenopodium album, darnel ryegrass (Lolium temulentum, hairy crabgrass (Digitaria sanguinalis and corncockle (Agrostemma githago.
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Fe, Cr, Ni, Cu, Mg, Al, Ti, and S contents in plants and soil of heaps of nickel smelting works
Energy Technology Data Exchange (ETDEWEB)
Banasova, V; Hajduk, J
1977-01-01
The writers established the Fe, Ce, Cr, Ni, Ca, Mg, Al, Ti and S contents in the neopedon of heaps piling up from processing of nickel ore as well as in the plants: Cardaria draba, Salsola cali, Agropyrum repens, Bromus erectus, Calamagrostis epigeios, Cynodon dactylon and Matricaria inodora, growing on such heaps. Ca, Mg and S contents were found to be higher in dicotyledons and Fe, Al, Ti, Ni and Cr contents higher in monocotyledons. The analyzed dicotyledons appeared to be concentrators of Ca and S. Highest Fe, Al, Ti, Ni and Cr contents were found in individuals of the species Agropyrum repens. The neopedon as well as the plants had extraordinarily high Cr concentrations. The species Salsola cali has been found to possess an unusually higher affinity to the dump substrate after processing of nickel ore and to be a concentrator of Mg. 16 references, 1 table.
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Directory of Open Access Journals (Sweden)
Janusz Lipecki
2013-12-01
Full Text Available From 1993 to 1997 a study of spatial distribution of most important weeds in apple orchard herbicide strips was performed. This study was continued in 1998, once the trees were cut down. As the time progressed, Epilobium adenocaulon Hausskn., Chenopodium album L., Polygonum aviculare L. and Atriplex patulum L. showed an increase in their occurrence. An opposite tendency was found with Erigeron canadensis L., Convolvulus arvensis L. and Taraxacum fficinale Web. Some species grew in patches (Convolvulus arvensis L., Chenopodium album L., Atriplex patulum L., while the others appeared sporadically throughout the orchard. In 1998, the decrease of occurrence of Epilobium Haussk. was observed. Simultaneously, this was coupled with an increase of occurrence of Taraxacum officinale Web., Erigeron caanadensis L. and Chenopodium album L. The predominating species in 1998 was Cerastium vulgatum L., followed by Lolium perenne L., Poa annua L. and Bromus mollis L.
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Assessment of macro and microelement accumulation capability of two aquatic plants
International Nuclear Information System (INIS)
Baldantoni, Daniela; Alfani, Anna; Di Tommasi, Paul; Bartoli, Giovanni; De Santo, Amalia Virzo
2004-01-01
The concentrations of four macroelements (C, N, P, S) and eight trace metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) were measured in the leaves and roots of the emergent plant, Phragmites communis Trin., and in the shoots and roots of the submersed Najas marina L., taken from Lake Averno (Naples, Italy). Phragmites communis leaves showed higher concentrations of carbon, nitrogen and phosphorus than roots, while the roots exhibited significantly higher concentrations of sulphur and trace metals. Najas marina roots also showed higher concentrations of sulphur and trace metals than shoots, but these differences were less marked than in Phragmites communis except for sulphur. Sulphur was the only macronutrient to show the highest concentrations in the roots. Phragmites communis roots had higher values of Cr, Cu, Fe, Mn and Ni than Najas marina roots. By contrast, Cd, Cr, Fe, Ni, Pb and Zn concentrations were higher in Najas marina shoots than in Phragmites communis leaves. Phragmites communis, available through the year, showing high capability to accumulate trace metals in the roots, appears a good monitor of lake contamination, better than Najas marina. - Element accumulation in roots and shoots of aquatic plants was used as a criteria for selecting useful biomonitors
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Directory of Open Access Journals (Sweden)
Yue Yuan
2017-01-01
Full Text Available Spartina alterniflora Loisel. is one of the most invasive species in the world. However, little is known about the role of artificial mowing in its invasiveness and competiveness. In this work, we studied the effect of mowing on its interspecific interactions with native species Phragmites australis (Cav. Trin ex Steud of the Yangtze Estuary, China. We calculated their relative neighbor effect (RNE index, effect of relative crowding (Dr index, and interaction strength (I index. The results showed that the RNE of Phragmites australis and Spartina alterniflora was 0.354 and 0.619, respectively, and they have competitive interactions. The mowing treatments can significantly influence the RNE of Phragmites australis and Spartina alterniflora on each other. Concretely, the RNE of Spartina alterniflora in the removal treatments was significantly higher than the value in the controls. But the RNE of Phragmites australis in the removal treatments was significantly lower than the value in the controls. Meanwhile, Dr of the two species on the targets was higher in the removal treatments than that in the controls, and the opposite was for I. We concluded that artificial mowing could promote the invasion of Spartina alterniflora by increasing its competitive performance compared with native species.
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TRABALHO E SAÚDE: O PAPEL DO MODELO DE GESTÃO DA EXCELÊNCIA NA EMPRESA BETA
Directory of Open Access Journals (Sweden)
Almiralva Ferraz Gomes
2008-12-01
Full Text Available As atuais transformações produtivas e organizacionais têm fortes implicações no trabalho e na saúde do trabalhador. Embora fatores econômicos tenham se constituído como impulsionadores das mudanças nos modelos de gestão, as políticas de gestão de pessoas devem considerar aspectos que promovam a saúde do trabalhador, considerando efetivamente o trinômio: indivíduo-trabalhoorganização. O presente trabalho se propõe a caracterizar o modelo de gestão adotado por uma organização de grande porte do setor de serviços, no Estado da Bahia, no que diz respeito à saúde do trabalhador. Esta investigação possui um caráter descritivo e foi realizada a partir de pesquisa documental. Uma das principais constatações da presente pesquisa foi a de que a organização investigada, na implementação do seu modelo de gestão da excelência, vem incorporando boas práticas de relacionamento com os trabalhadores, o que, consequentemente, tem proporcionado um ambiente de proteção à saúde do trabalhador.
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Directory of Open Access Journals (Sweden)
Badr HAJJAJ
2016-12-01
Full Text Available In order to evaluate the efficacy of 11 cereal herbicides on no till soft wheat, two trials were conducted in Chaouia region during 2014-2015 growing season. Dominant species of weed flora in Sidi El Aidi site were: Bromus rigidus, Lolium rigidum and Avena sterilis. Dominant species of weed flora in Ouled Said site were: Avena sterilis, Centaurea diluta and Papaver rhoeas. The obtained results showed that “Pyroxsulam” and “Mesosulfuron Sodium + Iodosulfuron sodium” gavethe best efficacy on rip gut brome. Prosulfocarb provided excellent control of ryegrass but no effect on ripgut brome or wild oat. Broadleaf herbicides provided moderate to good control. “Mesosulfuron Sodium +Iodosulfuron sodium” need to be completed with an broadleaf herbicide in case centaurea diluta is present. “Pyroxsulam” need to be tank mixed with a broadleaf herbicide to widen its weeds spectrum. Treatment with “Pendimethalin”as pre-emergence herbicide allowed an early complete control of weeds and good crop selectivity.
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STEVENS, JAN F.; REED, RALPH L.; ALBER, SUSAN; PRITCHETT, LARRY; MACHADO, STEPHEN
2009-01-01
Meadowfoam (Limnanthes alba) is an oilseed crop grown in western Oregon. After extraction of the oil from the seeds, the remaining seed meal contains 2-4% of the glucosinolate, glucolimnanthin. We investigated the effect of fermentation of seed meal on its chemical composition and the effect of the altered composition on downy brome (Bromus tectorum) coleoptile emergence. Incubation of enzyme-inactive seed meal with enzyme-active seeds (1% by weight) resulted in complete degradation of glucolimnanthin and formation of 3-methoxybenzyl isothiocyanate in 28% yield. Fermentation in the presence of an aqueous solution of FeSO4 (10 mM) resulted in the formation of 3-methoxyphenylacetonitrile and 2-(3-methoxyphenyl)ethanethioamide, a novel natural product. The formation of the isothiocyanate, the nitrile and the thioamide, as a total, correlated with an increase of herbicidal potency of seed meal (r2 = 0.96). The results of this study open new possibilities for the refinement of glucosinolate-containing seed meals for use as bioherbicides. PMID:19170637
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Modeling Phosphorus Capture by Plants Growing in a Multispecies Riparian Buffer
Directory of Open Access Journals (Sweden)
J. M. Kelly
2012-01-01
Full Text Available The NST 3.0 mechanistic nutrient uptake model was used to explore P uptake to a depth of 120 cm over a 126 d growing season in simulated buffer communities composed of mixtures of cottonwood (Populus deltoids Bartr., switchgrass (Panicum virgatum L., and smooth brome (Bromus inermis Leyss. Model estimates of P uptake from pure stands of smooth brome and cottonwood were 18.9 and 24.5 kg ha−1, respectively. Uptake estimates for mixed stands of trees and grasses were intermediate to pure stands. A single factor sensitivity analysis of parameters used to calculate P uptake for each cover type indicated that Imax, k, ro, and Lo were consistently the most responsive to changes ranging from −50% to +100%. Model exploration of P uptake as a function of soil depth interval indicated that uptake was highest in the 0–30 cm intervals, with values ranging from 85% of total for cottonwood to 56% for switchgrass.
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Radiostrontium uptake by plants from different soil types in Kazakhstan
International Nuclear Information System (INIS)
Savinkov, A.; Semioshkina, N.; Howard, B.J.; Voigt, G.
2007-01-01
The transfer of 90 Sr to a range of different plant species grown on a range of different soil types in Kazakhstan, including three from the Semipalatinsk Test Site (STS), has been measured in a lysimeter experiment. 90 Sr uptake by Stipa spp was significantly higher than for other vegetation species. The uptake of 90 Sr from chernozem was significantly lower than that from the other soil types which is consistent with other literature. There was a significant negative relationship between 90 Sr uptake and calcium, humus and CEC concentration in the soil for Agropyrum spp, Artemisia spp but not for Stipa spp or Bromus spp. The transfer to vegetation from soil has been quantified using the aggregated transfer coefficients for each species. Tag values range from 0.6 to 11.9 m 2 kg -1 x 10 -3 over all measurements. The transfer of 90 Sr to plants from the Kazakh soils was low compared to previously reported data and to that given from literature reviews
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A phylogenetic analysis of the monogenomic Triticeae (Poaceae) based on morphology
DEFF Research Database (Denmark)
Seberg, Ole; Frederiksen, Signe Elisabeth
2001-01-01
not traditionally included in Aegilops s.J. Most of the 33 characters used in the analysis are coded as binary. The only four multistate characters in the matrix are treated as unordered. Three diploid species of Bromus are used as outgroup. The number of equally parsimonious trees found is very large (approx....... 170000; length = 107, ci = 0.36, ri = 0.75) and the strict consensus tree has an expectedly low level of resolution. However, most of the equally parsimonious trees owe their existence to an unresolved Aegilops clade. If this clade is replaced by its hypothetical ancestor, the number of equally...... parsimonious trees drops dramatically (48; length = 78, ci = 0.45, ri = 0.76). When trees for which more highly resolved compatible trees exist are excluded, only two trees remain. Bremer support is used as a measure of branch support. The trees based on morphology and on molecular data are largely incongruent....
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Stevens, Jan F; Reed, Ralph L; Alber, Susan; Pritchett, Larry; Machado, Stephen
2009-03-11
Meadowfoam ( Limnanthes alba ) is an oilseed crop grown in western Oregon. After extraction of the oil from the seeds, the remaining seed meal contains 2-4% of the glucosinolate glucolimnanthin. This study investigated the effect of fermentation of seed meal on its chemical composition and the effect of the altered composition on downy brome ( Bromus tectorum ) coleoptile emergence. Incubation of enzyme-inactive seed meal with enzyme-active seeds (1% by weight) resulted in complete degradation of glucolimnanthin and formation of 3-methoxybenzyl isothiocyanate in 28% yield. Fermentation in the presence of an aqueous solution of FeSO(4) (10 mM) resulted in the formation of 3-methoxyphenylacetonitrile and 2-(3-methoxyphenyl)ethanethioamide, a novel natural product. The formation of the isothiocyanate, the nitrile, and the thioamide, as a total, correlated with an increase of herbicidal potency of the seed meal (r(2) = 0.96). The results of this study open new possibilities for the refinement of glucosinolate-containing seed meals for use as bioherbicides.
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Belnap, J.; Sherrod, S.K.; Miller, M.E.
2003-01-01
Downy brome is an introduced Mediterranean annual grass that now dominates millions of hectares of western U.S. rangelands. The presence of this grass has eliminated many native species and accelerated wildfire cycles. The objective of this study was to identify soil additives that allowed germination but inhibited emergence of downy brome, while not affecting germination or emergence of the native perennial grass Hilaria jamesii. On the basis of data from previous studies, we focused on additives that altered the availability of soil nitrogen (N), phosphorus (P), and potassium (K). Most water-soluble treatments inhibited downy brome germination and emergence. We attribute the inhibitory effects of these treatments to excessive salinity and ion-specific effects of the additives themselves. An exception to this was oxalic acid, which showed no effect. Most water-insoluble treatments had no effect in soils with high P but did have an effect in soils with low P. Zeolite was effective regardless of P level, probably due to the high amounts of Na+ it added to the soil solution. Most treatments at higher concentrations resulted in lower downy brome emergence rates in soils currently dominated by downy brome than in uninvaded (but theoretically invadable) Hilaria soils. This difference is possibly attributable to inherent differences in labile soil P. In Stipa soils, where Stipa spp. grow, but which are generally considered to be uninvadable by downy brome, additions of high amounts of N resulted in lower emergence. This may have been an effect of NH4 + interference with uptake of K or other cations or toxicity of high N. We also saw a positive relationship between downy brome emergence and pH in Stipa soils. Hilaria development parameters were not as susceptible to the treatments, regardless of concentration, as downy brome. Our results suggest that there are additions that may be effective management tools for inhibiting downy brome in calcareous soils, including (1) high salt applications, (2) K-reducing additions (e.g., Mg), and (3) P-reducing additions.
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Wang, J.; Hansen, P.K.; Christensen, S.; Qi, G.Z.
2004-01-01
This article discusses the structure of weed reproduction incorporating the application of a mathematical model. This mathematical methodology enables the construction, testing and application of distribution models for the analysis of the structure of weed reproduction and weed ecology. The
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Fire as a long-term stewardship issue for soils contaminated with radionuclides in the western U.S
International Nuclear Information System (INIS)
Shafer, David S.; DuBois, David; Etyemezian, Vic; Kavouras, Ilias; Miller, Julianne J.; Nikolich, George; Stone, Mark
2007-01-01
On both U.S. Department of Energy (DOE) and U.S. Department of Defense sites in the southwestern United States (U.S.), significant areas of surface soils are contaminated with radionuclides from atmospheric nuclear testing, and with depleted uranium, primarily from military training. At DOE sites in Nevada, the proposed regulatory closure strategy for most sites is to leave contaminants in place with administrative controls and periodic monitoring. Closure-in-place is considered an acceptable strategy because the contaminated sites exist on access-restricted facilities, decreasing the potential risk to public receptor, the high cost and feasibility of excavating contaminated soils over large areas, and the environmental impacts of excavating desert soils that recover very slowly from disturbance. The largest of the contaminated sites on the Tonopah Test Range in Nevada covers over 1,200 hectares. However, a factor that has not been fully investigated in the long-term stewardship of these sites is the potential effects of fires. Because of the long half-lives of some of the contaminants (e.g., 24,100 years for 239 Pu) and changes in land-cover and climatic factors that are increasing the frequency of fires throughout the western U.S., it should be assumed that all of these sites will eventually burn, possibly multiple times, during the time frame when they still pose a risk. Two primary factors are contributing to increased fire frequency. The first is the spread of invasive grasses, particularly cheat grass (Bromus tectorum and Bromus rubens), which have out-competed native annuals and invaded inter-spaces between shrubs, allowing fires to burn easier. The second is a sharp increase in fire frequency and size throughout the western U.S. beginning in the mid-1980's. This second factor appears to correlate with an increase in average spring and summer temperatures, which may be contributing to earlier loss of soil moisture and longer periods of dry plant biomass
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Directory of Open Access Journals (Sweden)
Foggi Bruno
2014-06-01
Full Text Available Travišča v katerih prevladujeta vrsti Bromus erectus in/ali Brachypodium rupestre pokrivajo velike površine na podlagi iz peščenjaka in laporasto-glinastega peščenjaka (apnenec je izključen na Apeninih in območju pred njimi med provincama Pistoia in Arezzo (Toskana, srednja Italija. Naša raziskava je bila osredotočena na 71 neobjavljenih in 45 objavljenih vegetacijskih popisov iz Toskane in sosednjih območij. Originalni popisi opisujejo asociacije Astragalo monspessulani-Brometum erecti, Centaureo bracteatae-Brometum erecti in Ononido masquillerii-Brometum erecti. Popise smo obdelali z multivariatno analizo s katero smo zaznali 9 skupin. Konsistenstnost skupin smo preverili s povprečjem NMDS proti Ellenberg/Pignatti indikatorskim vrednostim in CCA proti horotipom in rastnim oblikam. Diagnostične vrste posameznih skupin smo določili z navezanostjo vrst, ki temelji na φ koeficientu asociacije. Z analizo smo podatkovni niz razdelili na dva klastra; prvi (A vključuje nekaj popisov termofilne cenoze z nižje nadmorske višine, ki jih opišemo kot prehod med submediteranskim aspektom razreda Festuco-Brometea in drugih mediteranskih zeliščnih in grmiščnih razredov; drugi klaster (B pa vključuje večino podatkovnega niza in ga lahko členimo na pionirske, mezokserofilne (skupini B1 in B2a in mezofilne združbe (skupina B2b. Popise klastrov B1 in B2a uvrščamo v asociacijo Coronillo minimae-Astragaletum monspessulanii in tri druge skupine: združba Plantago argentea-Carex caryophyllea, združba Tragopogon samaritani-Bromus erectus in Festuco trachyphyllae-Brometum erecti ass. nova. Mezofilna skupina (B2b vključuje popise asociacij Centaureo bracteatae-Brometum erecti in Ononido masquillerii- Brometum erecti, skupaj z delno spremenjeno združbo. Zaradi majhnih razlik v florističnem, ekološkem in horološkem pogledu med temi traviščnimi tipi predlagamo, da jih obravnavamo kot tri subasociacije Centaureo bracteatae
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Directory of Open Access Journals (Sweden)
Rafael Galbieri
2008-02-01
Full Text Available A brusone, causada por Pyricularia grisea (teleomorfa Magnaphorthe grisea, possui uma ampla gama de hospedeiros. No Brasil, arroz, trigo, triticale e cevada são as culturas que sofrem quedas significativas de produtividade devido ao ataque desse patógeno. Além desses cereais, outras gramíneas também têm apresentado sintomas dessa doença. Os objetivos dessa pesquisa foram: a caracterizar sexualmente isolados de P. grisea desses hospedeiros baseado na determinação do "mating type", fertilidade, sexualidade, compatibilidade sexual, b analisar o grau de compatibilidade sexual entre isolados de brusone de trigo e de outras gramíneas, c estudar a ocorrência da reprodução sexual em isolados de trigo. Os resultados obtidos através de ensaios "in vitro" constataram: 1 compatibilidade sexual de P. grisea do trigo com Bromus catharticus, Phalaris canariensis e X. triticosecal; 2 desbalanço entre porcentagem de MAT1-1 e MAT1-2, com predominância de MAT1-1 na população de P. grisea do trigo; 3 existência de um campo de isolados de trigo com baixa habilidade de cruzamento; 4 baixa possibilidade de ocorrência de reprodução sexual de P. grisea em campos de trigo, mesmo com existência de ambos "mating type" num mesmo campo.The blast disease caused by Pyricularia grisea (teleomorph Magnaporthe grisea has a wide host range. In Brazil, significant yield loss has been reported in rice, wheat, triticale and barley crops. Besides those cereals, several other gramineous plants have been shown to develop symptoms of this disease. The objectives of this research were: a sexually characterize isolates of P. grisea from these hosts based on the mating type, fertility, sexuality, sexual compatibility, b to analyze the degree of sexual compatibility among isolates from wheat and other grasses, c to verify the occurrence of sexual reproduction in isolates from wheat. Results of "in vitro" assay showed: 1 sexual compatibility of P. grisea of wheat with
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Directory of Open Access Journals (Sweden)
E. A. Bondarevich
2015-03-01
Full Text Available В работе рассмотрены особенности видового состава редких растительных сообществ с участием Melica virgata Turcz. ex Trin. (Poaceae. При сравнении с ранее известными данными по фитоценозам Монголии с участием этого вида выяснилось, что состав их значительно отличается. Также для фитоценозов из Восточного Забайкалья характерен уникальный видовой состав (заросли трех видов рода Rhamnus: R. davurica, R. erythroxylon, R. pissjaukovae + Ulmus pumila, с высоким проективным покрытием Melica virgata и участием крайне редкого вида для региона – Artemisia rutifolia, представленный на крайне ограниченной территории в бассейне реки Чикой (у с. Усть-Урлук. Сохранение комплекса видов требует создание охраняемой территории и включение в её состав нескольких наиболее ценных участков.
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Rachel Jones; Jeanne C. Chambers; Dale W. Johnson; Robert R. Blank; David I. Board
2015-01-01
Fire has profound effects on ecosystem properties, but few studies have addressed the effect of repeated burns on soil nutrients, and none have been conducted in cold desert ecosystems where invasion by exotic annual grasses is resulting in greater fire frequency. In a 5 year study, we examined effects of repeated burning, litter removal, and post-fire seeding on...
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Directory of Open Access Journals (Sweden)
Muhammad Hamid Raza
2015-01-01
Full Text Available Batch scale studies for the adsorption potential of novel biosorbent Phragmites karka (Trin, in its natural and treated forms, were performed for removal of mercury ions from aqueous solution. The study was carried out at different parameters to obtain optimum conditions of pH, biosorbent dose, agitation speed, time of contact, temperature, and initial metal ion concentration. To analyze the suitability of the process and maximum amount of metal uptake, Dubinin-Radushkevich (D-R model, Freundlich isotherm, and Langmuir isotherm were applied. The values of qmax for natural and treated biosorbents were found at 1.79 and 2.27 mg/g, respectively. The optimum values of contact time and agitation speed were found at 50 min and 150 rpm for natural biosorbent whereas 40 min and 100 rpm for treated biosorbent, respectively. The optimum biosorption capacities were observed at pH 4 and temperature 313 K for both natural P. karka and treated P. karka. RL values indicate that comparatively treated P. karka was more feasible for mercury adsorption compared to natural P. karka. Both pseudo-first-order and pseudo-second-order kinetic models were applied and it was found that data fit best to the pseudo-second-order kinetic model. Thermodynamic studies indicate that adsorption process was spontaneous, feasible, and endothermic.
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Directory of Open Access Journals (Sweden)
V. Huth
2013-10-01
Full Text Available Re-wetting minerotrophic fens has become an important strategy to mitigate climate change in Germany. However, recent studies report raised methane (CH4 effluxes during the first years after flooding. A minerotrophic fen in north-east Germany that was re-wetted 15 years ago was exposed to exceptionally heavy rainfall and freshwater flooding in August 2011. We measured CH4 effluxes from wetland vegetation stands dominated by Phragmites australis (Cav. Trin. ex Steud., Typha latifolia L. and Carex acutiformis Ehrh., using the closed-chamber method, fortnightly from March 2011 to March 2012 with extra sampling during the flooding. The respective annual effluxes of CH4 (mean ± 1 standard error from the three vegetation types were 18.5 ± 1.3, 21.1 ± 1.2 and 47.5 ± 5.0 g m-2 a-1, with the August effluxes contributing 40 %, 50 % and 10 % of the annual effluxes. Despite the freshwater flooding in August, annual CH4 effluxes from the 15-year re-wetted fen are similar to those reported from pristine fens. These results are promising because they indicate that, although CH4 effluxes are elevated after re-wetting, they may return to values typical for pristine fens after 15 years. Hence, re-wetting can achieve the purpose of reducing greenhouse gas effluxes from drained minerotrophic fens.
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Yang, Yang; Zhou, Zhengchao; Bai, Yanying; Jiao, Wentao; Chen, Weiping
2016-07-01
The distribution of trace elements (TEs) in water, sediment, riparian soil and dominant plants was investigated in the Fenghe River, Northwestern China. The Fenghe River ecosystem was polluted with Cd, Cr, Hg and Pb. There was a high pollution risk in the midstream and downstream regions and the risk level for Cd was much higher than that of the other elements. The average values of bioconcentration coefficient for Cd and Zn were 2.21 and 1.75, respectively, indicating a large accumulation of Cd and Zn in the studied species. With broad ecological amplitudes, L. Levl. et Vant. Trin., and L. had the greatest TE concentrations in aboveground and belowground biomass of the studied species and were potential biomonitors or phytoremediators for the study area. Multivariate techniques including cluster analysis, correlation analysis, principal component analysis, and canonical correspondence analysis were used to analyze the relations between TE concentrations in plants and various environmental factors. The soil element concentration is the main factor determining the accumulation of TEs in plants. The co-release behavior of common pollutants and TEs drove the accumulation of Hg, Cd, and As in the studied plants. Significant enrichment of some elements in the Fenghe River has led to a decline in the biodiversity of plants. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.
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Leaf anatomy of the genus Ehrharta (Poaceae in southern Africa: the Setacea group
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R. P. Ellis
1987-10-01
Full Text Available The leaf blade anatomy of the taxa of the Setacea group of species of the genus Ehrharta is described and illustrated. This group includes E. rupestris Nees ex Trin. subsp. rupestris, subsp. tricostata (Stapf Gibbs Russell and subsp. dodii (Stapf Gibbs Russell, as well as E. setacea Nees subsp. setacea, subsp. scabra (Stapf Gibbs Russell, subsp. uniflora (Burch, ex Stapf Gibbs Russell and subsp. disticha Gibbs Russell. All these taxa share a very characteristic leaf anatomy with inrolled or infolded leaves without keels and have adaxial ribs with interlocking prickles. The chlorenchyma is dense and compact with inwardly projecting invaginations visible in all taxa except E. setacea subsp. setacea. In E . setacea subsp. scabra typical arm cells are present. Abaxial costal and intercostal zones are not differentiated and stomata are absent. The long cells are hexagonal or inflated with sinuous walls. Silica bodies are single or paired and rounded in shape. Small hook-like prickles with short barbs are common. Microhairs with a short, truncated distal cell occur. This leaf anatomical structure differs considerably from that of the other species groups recognized in African Ehrharta and the Setacea group appears to be more distinct from the other groups than they are from each other.
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Morphology and anatomy of the diaspores and seedling of Paspalum (Poaceae, Poales
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MAYRA T. EICHEMBERG
2013-09-01
Full Text Available ABSTRACT The knowledge regarding of the diaspore and post-seminal development of Paspalum L. is important for grassland biodiversity conservation, based on their representativeness and genetic improvement of forage. The morphology of the diaspore and the post-seminal development of Paspalum dilatatum Poir. (rhizomatous, P. mandiocanum Trin. var. subaequiglume Barreto (stoloniferous, P. pumilum Nees. (decumbent caespitose and P. urvillei Steud. (erect caespitose was described to distinguish species with different growth forms and to survey the characters useful for taxonomy. P. dilatatum differs by presenting oval diaspores larger than the others, with five prominent nerves and trichomes; P. urvillei presents diaspores with one central nerve that is more developed than the two lateral nerves and trichomes; P. mandiocanum var. subaequiglume presents diaspores with trichomes only in the margin; and P. pumilum differs by presenting glabrous diaspores. The caryopsis involves the seed that presents the differentiated embryo and disposed laterally, an elliptical hilum in all of the studied species and a rostellum in P. dilatatum and P. mandiocanum var. subaequiglume. The post-seminal development is similar in the four species and begins with germination that is marked by the emergence of the coleorhiza, followed by the coleoptile. These characteristics are common to other Poaceae previously studied, indicating a pattern to the family and do not distinguish the growth forms.
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Burrell, A Millie; Pepper, Alan E; Hodnett, George; Goolsby, John A; Overholt, William A; Racelis, Alexis E; Diaz, Rodrigo; Klein, Patricia E
2015-05-01
Imperata cylindrica (Cogongrass, Speargrass) is a diploid C4 grass that is a noxious weed in 73 countries and constitutes a significant threat to global biodiversity and sustainable agriculture. We used a cost-effective genotyping-by-sequencing (GBS) approach to identify the reproductive system, genetic diversity and geographic origins of invasions in the south-eastern United States. In this work, we demonstrated the advantage of employing the closely related, fully sequenced crop species Sorghum bicolor (L.) Moench as a proxy reference genome to identify a set of 2320 informative single nucleotide and insertion-deletion polymorphisms. Genetic analyses identified four clonal lineages of cogongrass and one clonal lineage of Imperata brasiliensis Trin. in the United States. Each lineage was highly homogeneous, and we found no evidence of hybridization among the different lineages, despite geographical overlap. We found evidence that at least three of these lineages showed clonal reproduction prior to introduction to the United States. These results indicate that cogongrass has limited evolutionary potential to adapt to novel environments and further suggest that upon arrival to its invaded range, this species did not require local adaptation through hybridization/introgression or selection of favourable alleles from a broad genetic base. Thus, cogongrass presents a clear case of broad invasive success, across a diversity of environments, in a clonal organism with limited genetic diversity. © 2015 John Wiley & Sons Ltd.
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Electroweak Structure of Three- and Four-Body Nuclei
Energy Technology Data Exchange (ETDEWEB)
Marcucci, Laura Elisa [Old Dominion Univ., Norfolk, VA (United States)
2000-06-01
This work reports results for (i) the elastic electromagnetic form factors of the trin- of ucleons; (ii) the nuclear response functions of interest in ~ experiments, 3 He(~e; e 0 ) experiments, at VERSITY excitation energies below the deuteron breakup threshold; (iii) the astrophysical ark S-factor for proton weak capture on 3 He (the hep reaction). The initial and nal using state wave functions are calculated using the correlated hyperspherical harmonics onsisting method, from a realistic Hamiltonian consisting of the Argonne v 18 two-nucleon uclear and Urbana IX three-nucleon interactions. The nuclear electroweak charge and ts. current operators include one- and many-body components. The predicted mag- netic form factor of 3 H, charge form factors and static properties of both 3 H and ntal 3 He, are in satisfactory agreement with the experimental data. However, the po- sition of the zero in the magnetic form factor of 3 He is underpredicted by theory. disintegration The calculated nuclear response functions in 3 He electrodisintegration at thresh- er old are in good agreement with the experimental data, which have however rather s large errors. Finally, the astrophysical S-factor for the hep reaction is predicted ortant ' 4.5 larger than the value adopted in the standard-solar-model, with important consequences for the solar neutrino spectrum measured by the Super-Kamiokande collaboration.
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Radiostrontium uptake by plants from different soil types in Kazakhstan
Energy Technology Data Exchange (ETDEWEB)
Savinkov, A. [Scientific Research Agricultural Institute of the National Biotechnology Center, Ministry for Science and Higher Education of the Republic of Kazakhstan (SRAI), 480544, Gvardeiski (Kazakhstan)]. E-mail: Chebotar@srai.kz; Semioshkina, N. [GSF-Institut fuer Strahlenschutz, Ingolstaedter Land str.1, D-85764, Neuherberg (Germany)]. E-mail: semi@gsf.de; Howard, B.J. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)]. E-mail: bjho@ceh.ac.uk; Voigt, G. [Agency' s Laboratories - Seibersdorf, IAEA, Vienna (Austria)]. E-mail: g.voigt@iaea.org
2007-02-01
The transfer of {sup 90}Sr to a range of different plant species grown on a range of different soil types in Kazakhstan, including three from the Semipalatinsk Test Site (STS), has been measured in a lysimeter experiment. {sup 90}Sr uptake by Stipa spp was significantly higher than for other vegetation species. The uptake of {sup 90}Sr from chernozem was significantly lower than that from the other soil types which is consistent with other literature. There was a significant negative relationship between {sup 90}Sr uptake and calcium, humus and CEC concentration in the soil for Agropyrum spp, Artemisia spp but not for Stipa spp or Bromus spp. The transfer to vegetation from soil has been quantified using the aggregated transfer coefficients for each species. Tag values range from 0.6 to 11.9 m{sup 2} kg {sup -1}x 10{sup -3} over all measurements. The transfer of {sup 90}Sr to plants from the Kazakh soils was low compared to previously reported data and to that given from literature reviews.
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Directory of Open Access Journals (Sweden)
H. Madani
2012-07-01
Full Text Available The allelopathic effects of leaves at rosette stage of the hoary alyssum (Berteroa incana L. against some associated grasses like, prairie June grass (Koeleria macrantha, Idaho fescue (Festuca idahoensis, blue-bunch wheatgrass (Pseudoroegneria spicata and cheat grass (Bromus tectorum and its own were investigated. The experiment al materials used were the leaf extracts and its allelopathic effects on seed germination and seedling emergence of the abave mentioned grasses in Petri dishes. According to our study, leaves of hoary alyssum rosettes at stage have the potential to reduce germination rate, root and shoot growth of pasture grasses and hoary alyssum itself due to its allelopathic effect. The leaf leachate solution bioassays also showed that the germination of cheat grass was more susceptible to 4% solution of allelopathic extract of leaves. Hoary alyssum leaf extract also exhibited allelopathic self-inhibition, in both seedling root and shoot growth at 2 and 4% concentrations. Self- inhibitory allelopathic effects of hoary alyssum could also be important in preventing seed germination and seedling establishment of neighboring plant.
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Northward invading non-native vascular plant species in and adjacent to Wood Buffalo National Park
Energy Technology Data Exchange (ETDEWEB)
Wein, R.W.; Wein, G.; Bahret, S.; Cody, W.J. (Alberta University, Edmonton, AB (Canada). Canadian Circumpolar Institute)
A survey of the non-native vascular plant species in Wood Buffalo National Park, Canada's largest forested National Park, documented their presence and abundance in key locations. Most of the fifty-four species (nine new records) were found in disturbed sites including roadsides, settlements, farms, areas of altered hydrological regimes, recent bums, and intensive bison grazing. Species that have increased most in geographic area and abundance in recent years include [ital Agropyron repens], [ital Bromus inermis], [ital Chenopodium album], [ital Melilotus spp.], [ital Trifolium spp.], [ital Plantago major], [ital Achillea millefolium], [ital Crepis tectorum] and [ital Sonchus arvensis]. An additional 20 species, now common in the Peace River and Fort Vermilion areas, have the potential to invade the Park if plant communities are subjected to additional stress as northern climates are modified by the greenhouse effect and as other human-caused activities disturb the vegetation. It is recommended that permanent plots be located in key locations and monitored for species invasion and changing abundances as input to management plans.
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Magt & meninger: Pædagogiske værdiprofiler blandt personalet i danske børnehaver
Directory of Open Access Journals (Sweden)
Bent Olsen
2015-03-01
ænge frem mellem et stort antal variable på én gang. Dette arbejde med datasættet skrider frem over tre trin. Først fremkommer et rum af positioner baseret på respondenternes sociale baggrund og deres faglige og kulturelle ressourcer. Her bruges indikatorer på kulturel og social kapital i forlængelse af Pierre Bourdieus teoretiske rammeværk. Med svarene på en række spørgsmål fra børnehavens hverdagsliv konstrueres dernæst et rum af pædagogiske værdier. På det tredje og sidste trin sættes de to rum eller ”kort” i forbindelse med hinanden for at se, om den sociale struktur kan genfindes i rummet af pædagogiske værdier.Resultaterne viser, at der er sammenhænge mellem besiddelse af social og kulturel kapital, og det man værdsætter i det pædagogiske arbejde. Men projektet viser også, at personalet i vid udstrækning samler sig om de pædagogiske værdier på tværs af social baggrund, alder og position i stillingshierarkiet.
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Directory of Open Access Journals (Sweden)
Adriana Tiemi Nakamura
2009-03-01
Full Text Available O presente estudo objetivou verificar a existência de um padrão do desenvolvimento pós-seminal em Poaceae. Para tanto, foram estudadas as seguintes espécies: Olyra humilis Nees (Bambusoideae; Axonopus aureus P. Beauv. e Paspalum polyphyllum Nees ex Trin. (Panicoideae; Chloris elata Nees e Eragrostis solida Desv. (Chloridoideae. Procurou-se também comparar as estruturas da plântula de Poaceae com as demais monocotiledôneas. As espécies estudadas são plantas perenes, rizomatosas, cespitosas e apresentam cariopses de tamanhos diferentes. Apresentam sementes albuminosas; embrião lateral, diferenciado, com raiz endógena (adventícia; cotilédone dividido em hiperfilo (escutelo, bainha reduzida e hipofilo (coleóptilo; coleorriza (raiz primária reduzida e mesocótilo (eixo localizado entre o escutelo e coleóptilo. A presença de epiblasto (folha embrionária foi observada em Olyra humilis, Chloris elata e Eragrostis solida. O desenvolvimento pós-seminal é semelhante nas espécies estudadas e forma um padrão em Poaceae. Primeiramente, observa-se a emissão da coleorriza, que cresce no sentido geotrópico positivo, seguida do coleóptilo e plúmula que crescem em sentido contrário, a partir do desenvolvimento do mesocótilo. As primeiras folhas são semelhantes às folhas definitivas (metafilos das espécies, exceto em Olyra humilis, que são modificadas em catafilos e podem ser interpretadas como caráter basal em Bambusoideae. Raiz primária reduzida (coleorriza e hipofilo modificado em coleóptilo são considerados caracteres derivados em Poaceae, quando comparados com as demais monocotiledôneas.This work has aimed to verify the existence of a pattern of the post-seminal development in Poaceae. Thus, Olyra humilis Nees (Bambusoideae; Axonopus aureus P. Beauv. e Paspalum polyphyllum Nees ex Trin. (Panicoideae; Chloris elata Nees e Eragrostis solida Desv. (Chloridoideae have been studied. Besides, it was compared the structures of
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Energy Technology Data Exchange (ETDEWEB)
Romero Aguilar, Mariana [Centro de Investigacion en Biotecnologia, Universidad Autonoma del Estado de Morelos, Cuernavaca, Morelos (Mexico)]. E-mail: ortizhl@uaem.mx; Colin Cruz, Arturo [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Toluca, Estado de Mexico (Mexico); Sanchez Salinas, Enrique; Ortiz Hernandez, Ma. Laura [Centro de Investigacion en Biotecnologia, Universidad Autonoma del Estado de Morelos, Cuernavaca, Morelos (Mexico)
2009-08-15
Wastewater treatment is a priority at the global level, because it is important to have enough water of good quality, which will allow an improvement of environment, health and life quality. In Mexico, because of insufficient infrastructure, high costs, lack of maintenance and qualified staff, only 36 % of the generated wastewaters are treated, which generates the need for developing alternative technologies for their depuration. Artificial wetlands are an alternative due their high efficiency for removal of polluting agents and their low installation and maintenance costs. This paper evaluates the removal percentage of the organic charge of wastewaters in a treatment system of artificial wetlands of horizontal flux, with two vegetal species. The system was designed with three modules installed in a sequential way. At the first one, organisms of the species Phragmites australis (Cav.) Trin. ex Steudel were integrated; at the second, organisms of the species Typha dominguensis (Pers.) Steudel, and at the third, both species. The experimental modules were installed at the effluent of a primary treatment, which contains municipal wastewater coming from a research building. The following parameters were analyzed in the water: chemical oxygen demand (COD), ions of nitrogen (N-NO{sub 3}-, N-NO{sub 2}- y N-NH{sub 4}{sup +}) and total phosphorus. Additionally, the total count of bacteria associated to the system was evaluated. Results showed that the system is an option for the removal of organic matter and nutrients, of low operation and maintenance costs. [Spanish] El tratamiento de las aguas residuales es una cuestion prioritaria a nivel mundial, ya que es importante disponer de agua de calidad y en cantidad suficiente, lo que permitira una mejora del ambiente, la salud y la calidad de vida. En Mexico, debido a la insuficiente infraestructura, los altos costos, la falta de mantenimiento y de personal capacitado, solo 36 % de las aguas residuales generadas reciben
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Tarescavage, Anthony M; Alosco, Michael L; Ben-Porath, Yossef S; Wood, Arcangela; Luna-Jones, Lynn
2015-04-01
We investigated the internal structure comparability of Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) scores derived from the MMPI-2 and MMPI-2-RF booklets in a sample of 320 criminal defendants (229 males and 54 females). After exclusion of invalid protocols, the final sample consisted of 96 defendants who were administered the MMPI-2-RF booklet and 83 who completed the MMPI-2. No statistically significant differences in MMPI-2-RF invalidity rates were observed between the two forms. Individuals in the final sample who completed the MMPI-2-RF did not statistically differ on demographics or referral question from those who were administered the MMPI-2 booklet. Independent t tests showed no statistically significant differences between MMPI-2-RF scores generated with the MMPI-2 and MMPI-2-RF booklets on the test's substantive scales. Statistically significant small differences were observed on the revised Variable Response Inconsistency (VRIN-r) and True Response Inconsistency (TRIN-r) scales. Cronbach's alpha and standard errors of measurement were approximately equal between the booklets for all MMPI-2-RF scales. Finally, MMPI-2-RF intercorrelations produced from the two forms yielded mostly small and a few medium differences, indicating that discriminant validity and test structure are maintained. Overall, our findings reflect the internal structure comparability of MMPI-2-RF scale scores generated from MMPI-2 and MMPI-2-RF booklets. Implications of these results and limitations of these findings are discussed. © The Author(s) 2014.
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Data on wastewater treatment plant by using wetland method, Babol, Iran
Directory of Open Access Journals (Sweden)
Yousef Dadban Shahamat
2018-02-01
Full Text Available Date in this paper highlights the applications of constructed horizontal surface flow (HF-CW wetland with two different local plants (Louis latifoila and Phragmites -australis (Cav. Trin at the wastewater treatment plant in Babol city. This system was designed as an advanced treatment unit in field scale after the treatment plant. Parameters such as Total Dissolved Solid (TDS, Total Suspended Solid (TSS, Turbidity, Biological Oxygen Demand (BOD and Chemical Oxygen Demand (COD, were investigated. The result shows that treatment efficiency increases with the passage of time. The efficiency of Phragmites planted setups in open environment was fairly good for all studied parameters (28.6% of TDS, 94.4% for TSS, 79.8% for turbidity, 93.7% for BOD and 82.6% for COD. The efficiency of the latifoila set up was also good, but lower than that of Phragmites (26.5% of TDS, 76.9% for TSS, 71.5% for turbidity, 79.1 for BOD and 68.8% for COD. In brief, the obtained dates show that using local plants in (HF-CW wetland not only effectively reduces various contaminants from the effluent of the wastewater according to Effluent Guideline regulations (WHO & EPA, but it is also a cost- effective and environmentally friendly method. Also, it was calculated that in full scale operation [time (1 day and a depth (0.3 m], 8 ha of wetland was needed. Keywords: BOD, Babol, COD, Horizontal subsurface flow wetland, TSS, TSD
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Directory of Open Access Journals (Sweden)
Maristela de Oliveira Bauer
2008-01-01
Full Text Available Avaliou-se a influência das características anatômicas e dos sítios de lignificação dos tecidos sobre o valor nutritivo de lâminas foliares de quatro gramíneas coletadas nas estações chuvosa e seca. Amostras frescas das duas últimas lâminas foliares recém-expandidas, correspondentes à última e à penúltima posição no perfilho de capim-gordura (Melinis minutiflora Pal. De Beauv, capim-braquiária (Brachiaria decumbens Staph., capim-sapé (Imperata brasiliensis Trin. e capim-jaraguá (Hyparrhenia rufa (Nees Staph. foram avaliadas quanto às características anatômicas, segundo técnicas de microscopia de luz e varredura. Nessas amostras analisou-se a proporção de tecidos e de sítios de lignificação. Também foram determinadas as concentrações de fibra em detergente neutro (FDN, fibra em detergente ácido (FDA, lignina e celulose da parede celular, assim como a digestibilidade in vitro da matéria seca (DIVMS. Os dados foram analisados segundo delineamento inteiramente casualizado, com os tratamentos no esquema fatorial, com três repetições. Determinaram-se as correlações entre DIVMS, componentes químicos da parede celular e proporção de tecidos. Observou-se o mesmo padrão de proporção de tecidos e DIVMS no capim-gordura e no capim-braquiária, assim como nos capins sapé e jaraguá. A digestibilidade in vitro da matéria seca e os componentes da parede celular sofreram influência da estação, enquanto as características anatômicas não foram significativamente influenciadas por esse fator. Os capins gordura e braquiária caracterizaram-se por maiores proporções de bainha parenquimática do feixe e os capins sapé e jaraguá por maiores proporções de xilema e esclerênquima. Altos coeficientes negativos de correlação foram estabelecidos entre os coeficientes de digestibilidade e as proporções de xilema e esclerênquima, assim como com os teores de FDN, FDA e lignina das lâminas foliares.It was
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Revegetation following artificial disturbance. Progress report, 1 June 1975--29 February 1976
International Nuclear Information System (INIS)
Fraley, L. Jr.
1976-01-01
Areas at Rocky Flats that had previously been reseeded by Rocky Flats personnel were evaluated for seeding success. Only one species in the seed mixture, Agropyron smithii (western wheatgrass) made a significant contribution to the stand. Two other species which made important contributions but were not in the seed mixture were Bromus tectorum (cheatgrass) and B. inermis (smooth brome). The vegetation receiving chronic exposure to ionizing radiation at the Grasslands Irradiation Study Area appears to be near equilibrium although electromagnet failure prevented irradiation for approximately 3 months during late summer 1975. Secondary succession is continuing in the sectors given a seasonal, short-term exposure in 1969 but at exposures where the dominant species, Bouteloua gracilis (blue grama) was killed there is no indication that any recovery of the B. gracilis is taking place. In plots that were artificially disturbed by burning, scraping and tilling, recovery patterns in the burned plots most nearly parallel recovery patterns of the areas receiving intermediate damage from exposure to ionizing radiation. For the scraped and tilled plots, recovery patterns most nearly paralleled those receiving heavy damage from exposure to ionizing radiation where all B. gracilis was killed
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Forage seeding in rangelands increases production and prevents weed invasion
Directory of Open Access Journals (Sweden)
Josh Davy
2017-07-01
Full Text Available Increasing forage productivity in the Sierra foothill rangelands would help sustain the livestock industry as land availability shrinks and lease rates rise, but hardly any studies have been done on forage selections. From 2009 to 2014, in one of the first long-term and replicated studies of seeding Northern California's Mediterranean annual rangeland, we compared the cover of 22 diverse forages to determine their establishment and survivability over time. Among the annual herbs, forage brassica (Brassica napus L. and chicory (Cichorium intybus L. proved viable options. Among the annual grasses, soft brome (Bromus hordeaceus and annual ryegrass (Lolium multiflorum performed well. However, these species will likely require frequent reseeding to maintain dominance. Long-term goals of sustained dominant cover (> 3 years are best achieved with perennial grasses. Perennial grasses that persisted with greater than 50% cover were Berber orchardgrass (Dactylis glomerata, Flecha tall fescue (Lolium arundinaceum and several varieties of hardinggrass (Phalaris aquatica L., Perla koleagrass, Holdfast, Advanced AT. In 2014, these successful perennials produced over three times more dry matter (pounds per acre than the unseeded control and also suppressed annual grasses and yellow starthistle (Centaurea solstitialis L. cover.
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Goldstein, Harland L.; Miller, Mark E.; Yount, James C.; Reheis, Marith C.; Reynolds, Richard L.; Belnap, Jayne; Lamothe, Paul J.; McGeehan, John P.
2009-01-01
This report presents data and describes the methodology for physical, chemical and ecological measurements of sediment, soil, and vegetation, as well as age determinations of surficial deposits at Hatch Point, Canyon Rims area, Colorado Plateau, southeastern Utah. The results presented in this report support a study that examines geomorphic and soil factors that may influence boundaries between shrubland and grassland ecosystems in the study area. Shrubland ecosystems dominated by sagebrush (Artemisia tridentata) and grassland ecosystems dominated by native perennial grasses (for example, Hilaria jamesii and Sporabolis sp.) are high-priority conservation targets for the Federal Bureau of Land Management (BLM) and other resource managers because of their diversity, productivity, and vital importance as wildlife habitat. These ecosystems have been recognized as imperiled on a regional scale since at least the mid-1990s due to habitat loss (type conversions), land-use practices, and invasive exotic plants. In the Intermountain West, the exotic annual cheatgrass (Bromus tectorum) is recognized as one of the most pervasive and serious threats to the health of native sagebrush and grassland ecosystems through effects on fire regimes and resource conditions experienced by native species.
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Directory of Open Access Journals (Sweden)
Badr HAJJAJ
2016-12-01
Full Text Available In order to evaluate the efficacy of 18 sequences of pre and post emergence herbicides on weeds of no till faba bean and chickpea and their impact on crops grain yield, two trials were conducted during 2014-2015 growing season at Sidi El Aidi INRA research station and at a farmer’s farm in Ouled Said (Settat. Dominant species of weed flora in chickpea in Sidi El Aidi were: Bromus rigidus, Lolium rigidum, Avena sterilis, Cichorium endivia, Centaurea diluta, Emex spinosa and Papaver rhoeas. Dominant species of weed flora in faba bean at Ouled Said were: Avena sterilis, Plantago afra, Chrysanthemum coronarium, Centaurea diluta, Sonchus oleraceus and Silybum marianum. The obtained results showed that herbicides react differently on weed and crops. Treatments which showed good weed control and better selectivity provided the best crop yield. “Pendimethalin (1258,5 g/ha + Bentazon (960 g/ha” and “Acetochlor (2100 g/ha + Bentazon (960 g/ha” provided good weed control and good selectivity in horse bean crop. “Pendimethalin (1258,5 g/ha + Bentazon (960 g/ha” needs to be more tested on chickpea before its recommendation on this crop.
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International Nuclear Information System (INIS)
Severson, R.C.; Gough, L.P.
1976-01-01
The processing of phosphatic shale near Pocatello, Idaho has a direct influence on the element content of local vegetation and soil. Samples of big sagebrush (Artemisia tridentata Nutt. subsp. tridentata) and cheatgrass (Bromus tectorum L.) show important negative relations between the concentration of certain elements (Cd, Cr, F, Ni, P, Se, U, V, and Zn) and distance from phosphate processing factories. Plant tissues within 3 km of the processing factories contain unusually high amounts of these elements except Ni and Se. Important negative relations with distance were also found for certain elements (Be, F, Fe, K, Li, Pb, Rb, Th, and Zn) in A-horizon soil. Amounts of seven elements (Be, F, Li, Pb, Rb, Th, and Zn) being contributed to the upper 5 cm of the soil by phosphate processing, as well as two additional elements (U and V) suspected as being contributed to soil, were estimated, with F showing the greatest increase (about 300 kg/ha) added to soils as far as 4 km downwind from the factories. The greatest number of important relations for both plants and soils was found downwind (northeast) of the processing factories
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Susan E. Meyer; Phil S. Allen
2009-01-01
A principal goal of seed germination modelling for wild species is to predict germination timing under fluctuating field conditions. We coupled our previously developed hydrothermal time, thermal and hydrothermal afterripening time, and hydration-dehydration models for dormancy loss and germination with field seed zone temperature and water potential measurements from...
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International Nuclear Information System (INIS)
Bragato, Claudia; Brix, Hans; Malagoli, Mario
2006-01-01
A recently constructed wetland, located in the Venice lagoon watershed, was monitored to investigate growth dynamics, nutrient and heavy metal shoot accumulation of the two dominating macrophytes: Phragmites australis and Bolboschoenus maritimus. Investigations were conducted over a vegetative season at three locations with different distance to the inlet point to assess effects on vegetation. The distance from the inlet did not affect either shoot biomass or nutrients (N, P, K and Na) and heavy metals (Cr, Ni, Cu and Zn) shoot content. With the exception of Na, nutrient and heavy metal concentrations were higher in shoots of P. australis than in B. maritimus. Heavy metal concentration in the incoming water and in the soil was not correlated to the plant content of either species. Shoot heavy metal concentrations were similar to those reported in the current literature, but accumulation generally increased towards the end of the growing season. - Heavy metal shoot concentration in Phragmites australis and Bolboschoenus maritimus increased significantly at the end of the growing season
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Assunção-Albuquerque, M J T; Peso-Aguiar, M C; Albuquerque, F S
2010-08-01
There is much evidence to support that Mocis latipes larvae (Guenèe, 1852) are the most dangerous pasture pest and usually cause large environmental losses. However, no studies have been carried out to identify the instars during which this moth causes the most damage to the environment. Here we calculate M. latipes larval energy budget to assess its consumption across all instars and estimate the consumption/amount of plant biomass required to complete its larval development. Assimilation, respiration, consumption, excretion, gross growth efficiency and net growth efficiency were calculated. Pearson correlations were used to identify the best predictors that influenced larval growth and weight. Across all instars consumption increased exponentially, especially during the last phase. M. latipes larvae consumed ca 13.8% of total food from the first to the fifth instar, whereas during the sixth instars these larvae consumed ca 72.6%. Results also show that the best gross growth and net growth efficiency were obtained when larvae reached the fifth instar. The results also show that one larva of Mocis latipes consumes 1.02 g (dry weight) of Paspalum maritimum (Trin) in 19 days. Overall, our results indentified the sixth instar as the most destructive instar of this insect. Thus, once we know the most destructive instars of this pest, measures can be taken to disable M. latipes larval development and consequently stop their increase in plant consumption, reducing ecological and economic damage. This knowledge may eventually lead to reduced agricultural damage and contribute to sustainable farming strategies.
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Metodik til studiet af strategiske ledelsesprocesser i organisationer
Directory of Open Access Journals (Sweden)
Jørgen Gulddahl Rasmussen
2010-10-01
Full Text Available Denne artikel handler om at skabe viden om en hverdagspraksis, der sjældent er sat ord på. Den behandler de ledelsesprocesser, der i virksomheder producerer strategi og omsætter sådanne strategier i produktive handlinger. Det er processer, der i små og mellemstore virksomheder er præget af intuition og af meget uformelle samspil mellem virksomhedsledere og medarbejdere. Metodikken er en videreudvikling af de metoder til produktion af kvalitative data, som FIRM-gruppen har eksperimenteret med gennem nogle år. Artiklen kan ses som en afrapportering af et flerårigt metodeudviklingsarbejde. Da erfaringer fra sådanne virksomheder viser, at strategiske processer i høj grad udvikler sig gennem uformel kommunikation, og at lederes intuition spiller en meget stor rolle, arbejder metodikken med en struktureret udviklingsdialog mellem et mindre antal virksomhedsledere med strategiske opgaver og forskere. Denne udviklingsdialog har til formål at følge og forstå de processer, der skaber ledernes egne praksisrelaterede ”teorier” for strategisk handling. Efter en præsentation af temaet gennemgås metodikkens praktiske fremgangsmåde med undersøgelser i en række virksomheder, opbygning af cases i samarbejde med ledere fra disse virksomheder, diskussion af disse og foreløbige konklusioner hen mod de næste trin i metodikken. Artiklen er skrevet samtidigt med arbejdet på et igangværende forskningsprojekt og vil derfor både være en præsentation og en udvikling af muligheder og vanskeligheder i metodikken.
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Uma crítica da utilização da análise de conteúdo qualitativa em psicologia
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Sonia Maria Guedes Gondim
2014-06-01
Full Text Available O objetivo deste artigo é analisar os processos inferenciais que estão na base da interpretação de dados qualitativos em Análise de Conteúdo, os quais envolvem o trinômio teoria-fenômeno-dado. Na primeira seção é apresentado um breve histórico desse método e de suas principais modalidades ou técnicas, e a segunda são discutidos os procedimentos-padrão de uma Análise de Conteúdo categorial na perspectiva de Bardin. Discutem-se os processos de codificação e categorização e os respectivos mecanismos lógicos subjacentes: indução e dedução. São introduzidos alguns questionamentos e reflexões epistemológicas referentes à operacionalização desses dois mecanismos no contexto da Análise de Conteúdo, alertando para a impossibilidade de tomar essa técnica um recurso ad hoc. Nas duas seções seguintes são apresentados subsídios para servir de base a uma crítica da Análise de Conteúdo qualitativa: fenômeno, teoria e dados. Argumenta-se a favor do entendimento desse método como um recurso de análise de dados que deve visar mais à teorização do fenômeno psicológico investigado do que à descrição desses dados ou a sua organização (via categorização.
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Directory of Open Access Journals (Sweden)
MJT. Assunção-Albuquerque
Full Text Available There is much evidence to support that Mocis latipes larvae (Guenèe, 1852 are the most dangerous pasture pest and usually cause large environmental losses. However, no studies have been carried out to identify the instars during which this moth causes the most damage to the environment. Here we calculate M. latipes larval energy budget to assess its consumption across all instars and estimate the consumption/amount of plant biomass required to complete its larval development. Assimilation, respiration, consumption, excretion, gross growth efficiency and net growth efficiency were calculated. Pearson correlations were used to identify the best predictors that influenced larval growth and weight. Across all instars consumption increased exponentially, especially during the last phase. M. latipes larvae consumed ca 13.8% of total food from the first to the fifth instar, whereas during the sixth instars these larvae consumed ca 72.6%. Results also show that the best gross growth and net growth efficiency were obtained when larvae reached the fifth instar. The results also show that one larva of Mocis latipes consumes 1.02 g (dry weight of Paspalum maritimum (Trin in 19 days. Overall, our results indentified the sixth instar as the most destructive instar of this insect. Thus, once we know the most destructive instars of this pest, measures can be taken to disable M. latipes larval development and consequently stop their increase in plant consumption, reducing ecological and economic damage. This knowledge may eventually lead to reduced agricultural damage and contribute to sustainable farming strategies.
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Varietal Response of Chickpea (Cicer arietinum L.) Towards the Allelopathy of Different Weeds
International Nuclear Information System (INIS)
Rahamdad, K.; Ijaz, A.K.
2015-01-01
In a laboratory trial three chickpea varieties viz, Karak-I, Karak-III and Shenghar were tested against the phytotoxicity of five weed species: Parthenium hysterophorus L., Phragmites australis (Cav.) Trin., Datura alba L., Cyperus rotundus L. and Convolvulus arvensis L.in January 2013. The weed extracts were prepared at the rate of 120 g/L (w/v) after shade dry. The results indicated highly significant inhibitory effect of all the tested weed species on the chickpea varieties. The results also showed that the chickpea variety Karak-III was more susceptible to the phototoxicity of the tested weed extracts. Among the extract, C. arvensis proved much toxic in term of inhibition of germination by giving only 43.33% germination in comparison with control where 97.50% germination was recorded. On the other hand, the effect of P. australis extract was found a little stimulator by speeding the seed germination in all varieties and giving a low (2.21) mean germination time (MGT) value. From the current results it can be concluded that the infestation of C. arvensis can pollute the soil by accumulating toxic chemicals that leads to the germination failure and growth suppression in chickpea. Therefore, the prevention and removal of C. arvensis in the chickpea growing areas could be recommended. In addition, P. australis must be tested against chickpea weeds (chickpea varieties withstand against its phototoxicity), so that it can be popularized as bio herbicide in chickpea if it gave promising results in controlling chickpea weeds. (author)
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Pang, Y H; Zhao, J X; Du, W L; Li, Y L; Wang, J; Wang, L M; Wu, J; Cheng, X N; Yang, Q H; Chen, X H
2014-05-23
Leymus mollis (Trin.) Pilger (NsNsXmXm, 2n = 28), a wild relative of common wheat, possesses many traits that are potentially valuable for wheat improvement. In order to exploit and utilize the useful genes of L. mollis, we developed a multiple alien substitution line, 10DM50, from the progenies of octoploid Tritileymus M842-16 x Triticum durum cv. D4286. Genomic in situ hybridization analysis of mitosis and meiosis (metaphase I), using labeled total DNA of Psathyrostachys huashanica as probe, showed that the substitution line 10DM50 was a cytogenetically stable alien substitution line with 36 chromosomes from wheat and three pairs of Ns genome chromosomes from L. mollis. Simple sequence repeat analysis showed that the chromosomes 3D, 6D, and 7D were absent in 10DM50. Expressed sequence tag-sequence tagged sites analysis showed that new chromatin from 3Ns, 6Ns, and 7Ns of L. mollis were detected in 10DM50. We deduced that the substitution line 10DM50 was a multiple alien substitution line with the 3D, 6D, and 7D chromosomes replaced by 3Ns, 6Ns, and 7Ns from L. mollis. 10DM50 showed high resistance to leaf rust and significantly improved spike length, spikes per plant, and kernels per spike, which are correlated with higher wheat yield. These results suggest that line 10DM50 could be used as intermediate material for transferring desirable traits from L. mollis into common wheat in breeding programs.
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Free Trade Agreements in East Asian Countries: What Has Been Done and What Needs to Be Done?
Directory of Open Access Journals (Sweden)
JungTaik Hyun
2005-06-01
Full Text Available In this paper, we attempt to make a critical assessment of East Asia's free trIn this paper, we attempt to make a critical assessment of East Asia's free trade agreements (FTAs and suggest future steps of action. The FTAs of three Northeast Asian countries and five ASEAN countries are examined. We find that the concluded and currently negotiated FTAs of East Asia have produced a fairly limited impact on trade and welfare. The limitation came from the fact that the selection of FTA partners was not based on economic gains but on an ad hoc basis or a defensive purpose. Therefore, we suggest that East Asian countries concentrate FTA activities on trade partners with large trade volumes. In this regard, the successful conclusion of the ongoing Korea-Japan FTA negotiation is crucial, and the two governments need to dissociate social and historical concerns with economic considerations. The FTAs between China, Korea, Japan and the U.S. should immediately follow the Korea-Japan FTA to realize the potentials and to prevent biased specialization. The FTAs of East Asia allowed a wide range of exemptions to protect inefficient sectors such as agriculture. The proper approach, we suggest, is not to avoid the problem but to proceed with comprehensive agreements and thus maximize the gains of FTAs. Restructuring industries and reallocating resources to the sectors with comparative advantage, while providing adequate assistance programs, is required. We also note that East Asian countries should utilize existing unilateral, regional and multilateral methods of liberalization as well as bilateral FTAs.
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Directory of Open Access Journals (Sweden)
Mahgoub, O.
1994-01-01
Full Text Available Forty two, 21 males and 21 females, weaned Sudan Desert lambs were divided according to sex and live weight into three equal groups (3 x 14. Each group was randomly fed ad libitum for 11 weeks on one of three diets : humra Aristida funiculata Trin. & Rupr., humra plus limited amound of cotton seed cake, and a balanced ration. After those 11 weeks of differential feeding, each group was fed ad libitum on the balanced ration for 12 weeks. Six lambs (3 males and 3 females, 2 from each group, were randomly slaughtered at the start of the differential feeding period. Half of the remaining lambs (3 x 6 in each treatment group (3 x 12 were slaughtered at the end of the differential feeding period and the other half (3 x 6 at the end of the experiment. Live-weight growth of lambs fed humra, with or without supplemental cottonseed cake, was restricted compared to lambs fed the balanced ration. Upon refeeding, previously restricted growing lambs expressed compensatory growth. The pattern of relative increase in weight of body components was not affected by nutritional history but was influenced by body weight. Following refeeding, animals fed earlier humra with or without cottonseed cake, recovered in body conformation and composition. It was concluded that, supplementation of range lambs with a source of protein during the season of graze scarcity and afterwards feeding them on high energy yielding rations shortly before slaughter is recommended under the conditions of the Sudan.
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Chambers, Jeanne C.; Bradley, Bethany A.; Brown, Cynthia S.; D'Antonio, Carla; Germino, Matthew J.; Grace, James B.; Hardegree, Stuart P.; Miller, Richard F.; Pyke, David A.
2013-01-01
Alien grass invasions in arid and semi-arid ecosystems are resulting in grass–fire cycles and ecosystem-level transformations that severely diminish ecosystem services. Our capacity to address the rapid and complex changes occurring in these ecosystems can be enhanced by developing an understanding of the environmental factors and ecosystem attributes that determine resilience of native ecosystems to stress and disturbance, and resistance to invasion. Cold desert shrublands occur over strong environmental gradients and exhibit significant differences in resilience and resistance. They provide an excellent opportunity to increase our understanding of these concepts. Herein, we examine a series of linked questions about (a) ecosystem attributes that determine resilience and resistance along environmental gradients, (b) effects of disturbances like livestock grazing and altered fire regimes and of stressors like rapid climate change, rising CO2, and N deposition on resilience and resistance, and (c) interacting effects of resilience and resistance on ecosystems with different environmental conditions. We conclude by providing strategies for the use of resilience and resistance concepts in a management context. At ecological site scales, state and transition models are used to illustrate how differences in resilience and resistance influence potential alternative vegetation states, transitions among states, and thresholds. At landscape scales management strategies based on resilience and resistance—protection, prevention, restoration, and monitoring and adaptive management—are used to determine priority management areas and appropriate actions.
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Witwicki, Dana L.; Doescher, Paul S.; Pyke, David A.; DeCrappeo, Nicole M.; Perakis, Steven S.
2012-01-01
Annual grass invasion into shrub-dominated ecosystems is associated with changes in nutrient cycling that may alter nitrogen (N) limitation and retention. Carbon (C) applications that reduce plant-available N have been suggested to give native perennial vegetation a competitive advantage over exotic annual grasses, but plant community and N retention responses to C addition remain poorly understood in these ecosystems. The main objectives of this study were to (1) evaluate the degree of N limitation of plant biomass in intact versus B. tectorum-invaded sagebrush communities, (2) determine if plant N limitation patterns are reflected in the strength of tracer 15N retention over two growing seasons, and (3) assess if the strength of plant N limitation predicts the efficacy of carbon additions intended to reduce soil N availability and plant growth. Labile C additions reduced biomass of exotic annual species; however, growth of native A. tridentata shrubs also declined. Exotic annual and native perennial plant communities had divergent responses to added N, with B. tectorum displaying greater ability to use added N to rapidly increase aboveground biomass, and native perennials increasing their tissue N concentration but showing little growth response. Few differences in N pools between the annual and native communities were detected. In contrast to expectations, however, more 15N was retained over two growing seasons in the invaded annual grass than in the native shrub community. Our data suggest that N cycling in converted exotic annual grasslands of the northern Intermountain West, USA, may retain N more strongly than previously thought.
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Fernelius, Kaitlynn J.; Madsen, Matthew D.; Hopkins, Bryan G.; Bansal, Sheel; Anderson, Val J.; Eggett, Dennis L.; Roundy, Bruce A.
2017-01-01
Woody plant encroachment can increase nutrient resources in the plant-mound zone. After a fire, this zone is often found to be water repellent. This study aimed to understand the effects of post-fire water repellency on soil water and inorganic nitrogen and their effects on plant growth of the introduced annual Bromus tectorum and native bunchgrass Pseudoroegneria spicata. Plots centered on burned Juniperus osteosperma trees were either left untreated or treated with surfactant to ameliorate water repellency. After two years, we excavated soil from the untreated and treated plots and placed it in zerotension lysimeter pots. In the greenhouse, half of the pots received an additional surfactant treatment. Pots were seeded separately with B. tectorum or P. spicata. Untreated soils had high runoff, decreased soilwater content, and elevated NO3eN in comparison to surfactant treated soils. The two plant species typically responded similar to the treatments. Above-ground biomass and microbial activity (estimated through soil CO2 gas emissions) was 16.8-fold and 9.5-fold higher in the surfactant-treated soils than repellent soils, respectably. This study demonstrates that water repellency can influence site recovery by decreasing soil water content, promoting inorganic N retention, and impairing plant growth and microbial activity.
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Sonoran Desert winter annuals affected by density of red brome and soil nitrogen
Salo, L.F.; McPherson, G.R.; Williams, D.G.
2005-01-01
Red brome [Bromus madritensis subsp. rubens (L.) Husn.] is a Mediterranean winter annual grass that has invaded Southwestern USA deserts. This study evaluated interactions among 13 Sonoran Desert annual species at four densities of red brome from 0 to the equivalent of 1200 plants ma??2. We examined these interactions at low (3 I?g) and high (537 I?g NO3a?? g soila??1) nitrogen (N) to evaluate the relative effects of soil N level on survival and growth of native annuals and red brome. Red brome did not affect emergence or survival of native annuals, but significantly reduced growth of natives, raising concerns about effects of this exotic grass on the fecundity of these species. Differences in growth of red brome and of the three dominant non nitrogen-fixing native annuals at the two levels of soil N were similar. Total species biomass of red brome was reduced by 83% at low, compared to high, N levels, whereas that of the three native species was reduced by from 42 to 95%. Mean individual biomass of red brome was reduced by 87% at low, compared to high, N levels, whereas that of the three native species was reduced by from 72 to 89%.
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Vascular flora of saline lakes in the southern high plains of Texas and eastern New Mexico
Rosen, David J.; Conway, Warren C.; Haukos, David A.; Caskey, Amber D.
2013-01-01
Saline lakes and freshwater playas form the principal surface hydrological feature of the High Plains of the Southern Great Plains. Saline lakes number less than 50 and historically functioned as discharge wetlands with relatively consistent water availability due to the presence of one or more springs. Currently, less than ten saline lakes contain functional springs. A survey of vascular plants at six saline lakes in the Southern High Plains of northwest Texas and one in eastern New Mexico during May and September 2009 resulted in a checklist of 49 species representing 16 families and 40 genera. The four families with the most species were Asteraceae (12), Amaranthaceae (8), Cyperaceae (5), and Poaceae (12). Non-native species (Bromus catharticus, Poa compressa, Polypogon monspeliensis, Sonchus oleraceus, Kochia scoparia, and Tamarix ramosissima) accounted for 10% of the total species recorded. Whereas nearly 350 species of vascular plants have been identified in playas in the Southern High Plains, saline lakes contain a fraction of this species richness. The Southern High Plains saline lake flora is regionally unique, containing taxa not found in playas, with species composition that is more similar to temperate desert wetlands of the Intermountain Region and Gulf Coastal Plain of North America.
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Evaportranspiration studies for protective barriers: FY 1989 status report
International Nuclear Information System (INIS)
Link, S.O.; Thiede, M.E.; Downs, J.L.; Lettau, D.J.; Waugh, W.J.
1992-05-01
This document describes the results of technological developments and experiments at the Small Tube Lysimeter Facility. The objective of this research is to develop the capability to predict evapotranspiration in support of studies of water infiltration control for the Hanford Protective Barrier Development Program. Evapotranspiration is the combined loss of water from plants and soil surfaces to the atmosphere. This process must be predictable to adequately model soil water dynamics. We develop a miniature greenhouse (gas exchange chamber), where internal temperature and relative humidity can be controlled. With this device we measured evapotranspiration, transpiration, and carbon dioxide exchange rates from lysimeters with various surface and plant characteristics. We tested the effect on gas exchange rates and sand, gravel, admix, and soil surfaces in lysimeters where, cheat-grass, Bromus tectorum, had been seeded. Results showed that evapotranspiration was unaffected by the surface treatments. Estimated transpiration rates were higher for plants growing in sand compared with rates for plants growing in the admix and soil treatments. Soil evaporation rates were higher in the gravel treatment than in the sand treatment. Future research will entail parameterization of relationships between evapotranspiration, transpiration, soil evaporation, carbon dioxide exchange, and the abiotic and biotic factors that drive these processes for model development
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Common mycelial networks impact competition in an invasive grass.
Workman, Rachael E; Cruzan, Mitchell B
2016-06-01
Mycorrhizal hyphal complexes can connect multiple host plants to form common mycelial networks (CMNs) that may affect plant competitive outcomes and community composition through differential resource allocation. The impacts of CMN interactions on invasive plants are not well understood and could be crucial to the understanding of invasive plant establishment and success. We grew the invasive grass Brachypodium sylvaticum in intra- and interspecific pairings with native grass Bromus vulgaris in a greenhouse and controlled for the effects of CMN and root interactions by manipulating the belowground separation between competitors. Comparison of plant growth in pots that allowed CMN interactions and excluded root competition and vice versa, or both, allowed us to delineate the effects of network formation and root competition on invasive plant establishment and performance. Brachypodium sylvaticum grown in pots allowing for only hyphal interactions, but no root competition, displayed superior growth compared with conspecifics in other treatments. Invasive performance was poorest when pairs were not separated by a barrier. Shoot nitrogen content in B. sylvaticum was higher in mycorrhizal plants only when connections were allowed between competitors. Our results indicate that the presence of CMN networks can have positive effects on B. sylvaticum establishment and nutrient status, which may affect plant competition and invasion success. © 2016 Botanical Society of America.
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Binnicker, M. J.; Jespersen, D. J.; Harring, J. A.; Rollins, L. O.; Bryant, S. C.; Beito, E. M.
2008-01-01
The diagnosis of Lyme borreliosis (LB) is commonly made by serologic testing with Western blot (WB) analysis serving as an important supplemental assay. Although specific, the interpretation of WBs for diagnosis of LB (i.e., Lyme WBs) is subjective, with considerable variability in results. In addition, the processing, reading, and interpretation of Lyme WBs are laborious and time-consuming procedures. With the need for rapid processing and more objective interpretation of Lyme WBs, we evaluated the performances of two automated interpretive systems, TrinBlot/BLOTrix (Trinity Biotech, Carlsbad, CA) and BeeBlot/ViraScan (Viramed Biotech AG, Munich, Germany), using 518 serum specimens submitted to our laboratory for Lyme WB analysis. The results of routine testing with visual interpretation were compared to those obtained by BLOTrix analysis of MarBlot immunoglobulin M (IgM) and IgG and by ViraScan analysis of ViraBlot and ViraStripe IgM and IgG assays. BLOTrix analysis demonstrated an agreement of 84.7% for IgM and 87.3% for IgG compared to visual reading and interpretation. ViraScan analysis of the ViraBlot assays demonstrated agreements of 85.7% for IgM and 94.2% for IgG, while ViraScan analysis of the ViraStripe IgM and IgG assays showed agreements of 87.1 and 93.1%, respectively. Testing by the automated systems yielded an average time savings of 64 min/run compared to processing, reading, and interpretation by our current procedure. Our findings demonstrated that automated processing and interpretive systems yield results comparable to those of visual interpretation, while reducing the subjectivity and time required for Lyme WB analysis. PMID:18463211
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Binnicker, M J; Jespersen, D J; Harring, J A; Rollins, L O; Bryant, S C; Beito, E M
2008-07-01
The diagnosis of Lyme borreliosis (LB) is commonly made by serologic testing with Western blot (WB) analysis serving as an important supplemental assay. Although specific, the interpretation of WBs for diagnosis of LB (i.e., Lyme WBs) is subjective, with considerable variability in results. In addition, the processing, reading, and interpretation of Lyme WBs are laborious and time-consuming procedures. With the need for rapid processing and more objective interpretation of Lyme WBs, we evaluated the performances of two automated interpretive systems, TrinBlot/BLOTrix (Trinity Biotech, Carlsbad, CA) and BeeBlot/ViraScan (Viramed Biotech AG, Munich, Germany), using 518 serum specimens submitted to our laboratory for Lyme WB analysis. The results of routine testing with visual interpretation were compared to those obtained by BLOTrix analysis of MarBlot immunoglobulin M (IgM) and IgG and by ViraScan analysis of ViraBlot and ViraStripe IgM and IgG assays. BLOTrix analysis demonstrated an agreement of 84.7% for IgM and 87.3% for IgG compared to visual reading and interpretation. ViraScan analysis of the ViraBlot assays demonstrated agreements of 85.7% for IgM and 94.2% for IgG, while ViraScan analysis of the ViraStripe IgM and IgG assays showed agreements of 87.1 and 93.1%, respectively. Testing by the automated systems yielded an average time savings of 64 min/run compared to processing, reading, and interpretation by our current procedure. Our findings demonstrated that automated processing and interpretive systems yield results comparable to those of visual interpretation, while reducing the subjectivity and time required for Lyme WB analysis.
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Directory of Open Access Journals (Sweden)
Yue Yuan
Full Text Available The invasive species Spartina alterniora Loisel was introduced to the eastern coast of China in the 1970s and 1980s for the purposes of land reclamation and the prevention of soil erosion. The resulting interspecific competition had an important influence on the distribution of native vegetation, which makes studying the patterns and mechanisms of the interactions between Spartina alterniora Loisel and the native species Phragmites australis (Cav. Trin ex Steud in this region very important. There have been some researches on the interspecific interactions between P. australis and S. alterniora in the Dongtan wetland of Chongming, east China, most of which has focused on the comparison of their physiological characteristics. In this paper, we conducted a neighbor removal experiment along a tidal gradient to evaluate the relative competitive abilities of the two species by calculating their relative neighbor effect (RNE index. We also looked at the influence of environmental stress and disturbance on the competitive abilities of the two species by comparing interaction strength (I among different tidal zones both for P. australis and S. alterniora. Finally, we measured physiological characteristics of the two species to assess the physiological mechanisms behind their different competitive abilities. Both negative and positive interactions were found between P. australis and S. alterniora along the environmental gradient. When the direction of the competitive intensity index for P. australis and S. alterniora was consistent, the competitive or facilitative effect of S. alterniora on P. australis was stronger than that of P. australis on S. alterniora. The interspecific interactions of P. australis and S. alterniora varied with environmental conditions, as well as with the method used, to measure interspecific interactions.
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Jankju, M; Maghamnia, A
2010-07-01
Plant-plant interactions are known as the main biotic drivers of the vegetation dynamics. Therefore, understanding such processes is beneficial for the applied vegetation management. The aim of this research was to investigate the type and intensity of plant-plant interaction during the time course of a growth season. We studied ecophysiological aspects of facilitation and competition between two aridland shrubs, A. meschedensis Bunge and A. raddeanam Czernjak and one perennial grass, B. kopetdaghensis Krasch. Soil and plant sampling were carried out for shrubs and the grass that were either growing alone or the grass was growing under the canopy of shrubs. In Spring (May), soil humidity weight was higher under the shrubs+grass than the grass-only site. By the beginning of Summer (July) grass consumed the common soil water and rapidly terminated its yearly growth. Therefore, in August and September, soil humidity weight was lower under the shrubs+grass than shrub-only sites. Photosynthesis rate of B. kopetdaghensis was sharply reduced from the beginning towards the end of growth season, but was not varied between the different plant combinations. Leaf proline measurement in July indicated higher stress for B. kopetdaghensis that were growing under shrubs than those of open areas. In conclusion, we found facilitation effects of shrubs on the grass at the early times of growth season, but it shifted into the competition for water during summer times. The outcome of plant interaction was positive for the grass but negative for the shrubs, especially A. meschedensis.
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Directory of Open Access Journals (Sweden)
Koszałka Joanna
2015-03-01
Full Text Available The paper presents the results of research of plant macrofossils from the grain deposit deriving from the 18th/19th centuries. The analysed material included 24760 diaspores representing 73 taxa. The majority were cultivated cereal crop species, and there was also abundance of accompanying segetal weed species. About 95% of the gathered crop material was Secale cereale. Another important crop was Hordeum vulgare and there were also some remains of Avena sativa, Triticum aestivum, Fagopyrum esculentum. Cannabis sativa and Linum usitatissimum were found as well. Weeds competing with these crops were, among others, the following species: Agrostemma githago, Raphanus raphanistrum, Apera spica-venti, Bromus secalinus, Centaurea cyanus, Spergula arvensis, Thlaspi arvense, Viola arvensis/tricolor, Fallopia convolvulus, Polygonum persicaria, Mentha arvensis, Anthemis arvensis, Papaver rhoeas, Rumex acetosella, Scleranthus annuus, Aphanes arvensis, Setaria pumila, Setaria viridis/verticilata. Extremely large presence of wild plant diaspores in the material allowed conducting economic and environmental interpretations. Reconstruction methods applied, used primarily in the case of macroremains from granaries, were fully applicable to the analysed plant residues. Weed species composition in the analysed material showed that they were mostly typical for the main winter crop. Some amount of species typical for other habitats were also found and they probably came from the near-by rye field. The presence of perennial diaspores indicated that the field was probably set aside
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Klabi, Rim; Bell, Terrence H; Hamel, Chantal; Iwaasa, Alan; Schellenberg, Mike; Raies, Aly; St-Arnaud, Marc
2015-01-01
Adding inorganic P- and N-fixing legumes to semi-arid grasslands can increase forage yield, but soil nutrient concentrations and plant cover may also interact to modify soil fungal populations, impacting short- and long-term forage production. We tested the effect of plant assemblage (seven native grasses, seven native grasses + the domesticated N-fixing legume Medicago sativa, seven native grasses + the native N-fixing legume Dalea purpurea or the introduced grass Bromus biebersteinii + M. sativa) and soil P concentration (addition of 0 or 200 P2O5 kg ha(-1) at sowing) on the diversity and community structure of arbuscular mycorrhizal (AM) fungi and total fungi over two consecutive years, using 454-pyrosequencing of 18S rDNA and ITS amplicons. Treatment effects were stronger in the wet year (2008) than the dry year (2009). The presence of an N-fixing legume with native grasses generally increased AM fungal diversity, while the interaction between soil P concentration and plant assemblage modified total fungal community structure in 2008. Excluding interannual variations, which are likely driven by moisture and plant productivity, AM fungal communities in semi-arid grasslands appear to be primarily affected by plant assemblage composition, while the composition of other fungi is more closely linked to soil P. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Directory of Open Access Journals (Sweden)
Gebrewahd Amha Abesha
2014-06-01
Full Text Available An existence of information in the form database and full knowledge of grazing land vegetation resources and trend over time is essential for management decisions. This study was conducted in Kiltew -Awelaelo, eastern Tigray, Ethiopia. The study aimed to investigate species composition and diversity of the herbaceous vegetation, and examine the physical soil condition of the grazing lands. A total of 45 quadrats measuring 20m×20m (400m2 were laid out in 15 sample sites from three corresponding land use types (i.e. ten year enclosure, five year enclosure and open grazing land. From each land use type five sites having three quadrats were investigated. Each quadrat was laid out at an interval of 400m in five parallel transects each 200m apart from other. To collect data of herbaceous and soil five randomly located 1m2 area each, was selected and marked, within each 400m2 sample quadrat of sample sites located along the main transect. There was significant (PBracharia sp., Bromus pectinatus, Chloris gayana, Cenchurs cilarias, chloris radiata, Cynodon dactylon, Dactyloctenium aegyptium, Digitaria Velutina, Eragrostis teniufolia, Lintonia nutans, Setaria pumila, Seteria verticillate, and Tragus racemosus all occurred frequently forming the major constituents of the sites. Therefore, regeneration from area enclosure can be on advocated practice for grazing lands rehabilitation.
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Regional climate model downscaling may improve the prediction of alien plant species distributions
Liu, Shuyan; Liang, Xin-Zhong; Gao, Wei; Stohlgren, Thomas J.
2014-12-01
Distributions of invasive species are commonly predicted with species distribution models that build upon the statistical relationships between observed species presence data and climate data. We used field observations, climate station data, and Maximum Entropy species distribution models for 13 invasive plant species in the United States, and then compared the models with inputs from a General Circulation Model (hereafter GCM-based models) and a downscaled Regional Climate Model (hereafter, RCM-based models).We also compared species distributions based on either GCM-based or RCM-based models for the present (1990-1999) to the future (2046-2055). RCM-based species distribution models replicated observed distributions remarkably better than GCM-based models for all invasive species under the current climate. This was shown for the presence locations of the species, and by using four common statistical metrics to compare modeled distributions. For two widespread invasive taxa ( Bromus tectorum or cheatgrass, and Tamarix spp. or tamarisk), GCM-based models failed miserably to reproduce observed species distributions. In contrast, RCM-based species distribution models closely matched observations. Future species distributions may be significantly affected by using GCM-based inputs. Because invasive plants species often show high resilience and low rates of local extinction, RCM-based species distribution models may perform better than GCM-based species distribution models for planning containment programs for invasive species.
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Panthaleus major /Duges/ of cereals in Bulgaria
Directory of Open Access Journals (Sweden)
V. Maneva
2016-12-01
Full Text Available Abstract. Until recently, Penthaleus major (Dugès has not been recognized as an economically significant pest for the cereal crops. After climatic changes, its population began to grow and inflict damages around the world. The aim of this study was to investigate its distribution in Bulgaria and establish whether it presents a danger to the cereal crops. In the autumn of 2015 and the spring of 2016, a monitoring survey was conducted to establish Penthaleus major (Dugès with the cereal crops in Bulgaria. Over 60 sowed fields were investigated from all around the country. Samples were taken to identify the pest. It was established that Penthaleus major (Dugès inflicted harm to the wheat in north-eastern (12-14 mites per stem and south-eastern Bulgaria (6-8 mites per stem. Its density was under the threshold of economic harm. There was not found infestation of barley, rye, oat and triticale. On the field boundaries bordering the areas attacked by the mite were reported the following weeds: Capsella bursa pastoris (L. Medic, Descurania sophia (L. Welb. et Berth, Senecio spp., Sisymbrium orientale Torn., Taraxsacum officinale Weber, Anthemis spp., Bromus arvensis L., Eragrostis pilosa (L. P.B. Lolium temulentum L., which can be habitat for Penthaleus major (Dugès.
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Alguacil, M. M.; Torrecillas, E.; Roldán, A.; Díaz, G.; Torres, P.
2012-04-01
The arbuscular mycorrhizal fungi (AMF) communities composition regulate plant interactions and determine the structure of plant communities. In this study we analysed the diversity of AMF in the roots of two perennial gypsophyte plant species, Herniaria fruticosa and Senecio auricula, and an annual herbaceous species, Bromus rubens, growing in a gypsum soil from a semiarid area. The objective was to determine whether perennial and annual host plants support different AMF communities in their roots and whether there are AMF species that might be indicators of specific functional plant roles in these ecosystems. The roots were analysed by nested PCR, cloning, sequencing of the ribosomal DNA small subunit region and phylogenetic analysis. Twenty AMF sequence types, belonging to the Glomus group A, Glomus group B, Diversisporaceae, Acaulosporaceae, Archaeosporaceae and Paraglomeraceae, were identified. Both gypsophyte perennial species had differing compositions of the AMF community and higher diversity when compared with the annual species, showing preferential selection by specific AMF sequences types. B. rubens did not show host specificity, sharing the full composition of its AMF community with both perennial plant species. Seasonal variations in the competitiveness of AM fungi could explain the observed differences in AMF community composition, but this is still a working hypothesis that requires the analysis of further data obtained from a higher number of both annual and perennial plant species in order to be fully tested.
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Viral pathogen production in a wild grass host driven by host growth and soil nitrogen.
Whitaker, Briana K; Rúa, Megan A; Mitchell, Charles E
2015-08-01
Nutrient limitation is a basic ecological constraint that has received little attention in studies on virus production and disease dynamics. Nutrient availability could directly limit the production of viral nucleic acids and proteins, or alternatively limit host growth and thus indirectly limit metabolic pathways necessary for viral replication. In order to compare direct and indirect effects of nutrient limitation on virus production within hosts, we manipulated soil nitrogen (N) and phosphorus (P) availability in a glasshouse for the wild grass host Bromus hordeaceus and the viral pathogen Barley yellow dwarf virus-PAV. We found that soil N additions increased viral concentrations within host tissues, and the effect was mediated by host growth. Specifically, in statistical models evaluating the roles of host biomass production, leaf N and leaf P, viral production depended most strongly on host biomass, rather than the concentration of either nutrient. Furthermore, at low soil N, larger plants supported greater viral concentrations than smaller ones, whereas at high N, smaller plants supported greater viral concentrations. Our results suggest that enhanced viral productivity under N enrichment is an indirect consequence of nutrient stimulation to host growth rate. Heightened pathogen production in plants has important implications for a world facing increasing rates of nutrient deposition. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
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Interaction of historical and nonhistorical disturbances maintains native plant communities.
Davies, K W; Svejcar, T J; Bates, J D
2009-09-01
Historical disturbance regimes are often considered a critical element in maintaining native plant communities. However, the response of plant communities to disturbance may be fundamentally altered as a consequence of invasive plants, climate change, or prior disturbances. The appropriateness of historical disturbance patterns under modern conditions and the interactions among disturbances are issues that ecologists must address to protect and restore native plant communities. We evaluated the response of Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh plant communities to their historical disturbance regime compared to other disturbance regimes. The historical disturbance regime of these plant communities was periodic fires with minimal grazing by large herbivores. We also investigated the influence of prior disturbance (grazing) on the response of these communities to subsequent disturbance (burning). Treatments were: (1) ungrazed (livestock grazing excluded since 1936) and unburned, (2) grazed and unburned, (3) ungrazed and burned (burned in 1993), and (4) grazed and burned. The ungrazed-burned treatment emulated the historical disturbance regime. Vegetation cover, density, and biomass production were measured the 12th, 13th, and 14th year post-burning. Prior to burning the presence of Bromus tectorum L., an exotic annual grass, was minimal (resilience to more severe disturbances. Modern deviations from historical conditions can alter ecosystem response to disturbances, thus restoring the historical disturbance regime may not be an appropriate strategy for all ecosystems.
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Jeanne C. Chambers; Bethany A. Bradley; Cynthia S. Brown; Carla D' Antonio; Matthew J. Germino; James B. Grace; Stuart P. Hardegree; Richard F. Miller; David A. Pyke
2014-01-01
Alien grass invasions in arid and semi-arid ecosystems are resulting in grass-fire cycles and ecosystem-level transformations that severely diminish ecosystem services. Our capacity to address the rapid and complex changes occurring in these ecosystems can be enhanced by developing an understanding of the environmental factors and ecosystem attributes that determine...
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Separation techniques for the clean-up of radioactive mixed waste for ICP-AES/ICP-MS analysis
International Nuclear Information System (INIS)
Swafford, A.M.; Keller, J.M.
1993-01-01
Two separation techniques were investigated for the clean-up of typical radioactive mixed waste samples requiring elemental analysis by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) or Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). These measurements frequently involve regulatory or compliance criteria which include the determination of elements on the EPA Target Analyte List (TAL). These samples usually consist of both an aqueous phase and a solid phase which is mostly an inorganic sludge. Frequently, samples taken from the waste tanks contain high levels of uranium and thorium which can cause spectral interferences in ICP-AES or ICP-MS analysis. The removal of these interferences is necessary to determine the presence of the EPA TAL elements in the sample. Two clean-up methods were studied on simulated aqueous waste samples containing the EPA TAL elements. The first method studied was a classical procedure based upon liquid-liquid extraction using tri-n- octylphosphine oxide (TOPO) dissolved in cyclohexane. The second method investigated was based on more recently developed techniques using extraction chromatography; specifically the use of a commercially available Eichrom TRU·Spec trademark column. Literature on these two methods indicates the efficient removal of uranium and thorium from properly prepared samples and provides considerable qualitative information on the extraction behavior of many other elements. However, there is a lack of quantitative data on the extraction behavior of elements on the EPA Target Analyte List. Experimental studies on these two methods consisted of determining whether any of the analytes were extracted by these methods and the recoveries obtained. Both methods produced similar results; the EPA target analytes were only slightly or not extracted. Advantages and disadvantages of each method were evaluated and found to be comparable
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Bioaccumulation of Aluminium in Hydromacrophytes in Polish Coastal Lakes
Directory of Open Access Journals (Sweden)
Senze Magdalena
2015-03-01
Full Text Available The research on aluminium content was conducted in water and on aquatic flora of Polish lakes in the central part of the coast. The study included the lakes Sarbsko, Choczewskie, Bia.e, K.odno, D.brze and Salino investigated in the summer of 2013. The examined lakes belong mainly to the direct basin of the Baltic Sea. Samples of aquatic plants and lake waters were collected. In the water samples pH and electrolytic conductivity were measured. The aluminium content was determined both in water and aquatic plants. Submerged hydromacrophyte studies included Myriophyllum alterniflorum L., Potamogeton perfoliatus L. and Ceratophyllum demersum L. Emergent hydromacrophyte studies included Phragmites australis (Cav. Trin. ex Steud., Juncus bulbosus L., Iris pseudacorus L., Eleocharis palustris (L. Roem. % Schult., Phalaris arundinacea L., Carex riparia Curt., Mentha aquatic L., Stratiotes aloides L., Alisma plantago-aquatica L., Glyceria maxima (Hartman Holmb., Sagittaria sagittifolia L., Scirpus lacustris L. and Typha angustifolia L. The purpose of this investigation was the determination of the aluminium content in submerged and emergent hydromacrophytes and also the definition of their bioaccumulative abilities. The average concentration of aluminium in water was 2.68 fęg Al dm.3. The average content of aluminium in plants was 2.8015 mg Al kg.1. The bioaccumulation factor ranged from BCF=19.74 to BCF=16619. On the basis of the analysis of the aluminium content in water and aquatic plants results show that both water and plants were characterized by a moderate level of aluminium. The recorded concentrations indicate a mid-range value and are much lower than those which are quoted for a variety of surface waters in various parts of the world.
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Directory of Open Access Journals (Sweden)
Miguel CAÑEDO-ARGÜELLES
2009-08-01
Full Text Available The epiphytic macroinvertebrate communities associated with the Common Reed, Phragmites australis (Cav. Trin. ex Steudel, were examined seasonally from summer 2004 to spring 2005 in eleven coastal lagoons of the Llobregat Delta (NE Spain following the method proposed by Kornijów & Kairesalo (1994. The aims of the study were to: 1 characterise and quantify changes in epiphytic macroinvertebrate communities along environmental gradients; 2 assess the contribution of elements of the epiphytic compartment to structuring the community; 3 define the optima and tolerances of selected epiphytic macroinvertebrate taxa for the most relevant ecological factors responsible for assemblage composition; and 4 identify possible epiphytic species assemblages that would allow a lagoon’s typology to be established, as well as their representative indicator species. Communities showed statistically significant seasonal variation, with two faunal peaks: one in summer, with high chironomid densities, and the other in winter, with high naidid densities. These peaks showed a clear response to the influence of environmental factors. Salinity explained the highest percentage of total variance (36%, while trophic variables (nutrients, phytoplanktonic chlorophyll-a, and total organic carbon and epiphyton biomass (19.2 and 4% of total variance explained, respectively were secondary. Three different epiphytic macroinvertebrate species assemblages could be defined. These assemblages were directly linked to conductivity conditions, which determined the rate of survival of certain taxa, and to the existence of a direct connection with the sea, which permitted the establishment of "brackish-water" species. In spite of the existence of these species assemblages, the species composition and biomass of epiphytic macroinvertebrates and epiphyton differed substantially between lagoons; both elements were subject to changes in the environment, which finally determined the site
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Comparative anthelmintic activity investigation of selected ethno-medicinal weeds
Pueblos, Kirstin Rhys S.; Bajalla, Mark; Pacheco, Dixie; Ganot, Sheila; Paig, Daisy; Tapales, Radyn; Lagare, Jeanne; Quimque, Mark Tristan J.
2017-01-01
Helminth infections are one of the seriously neglected potent diseases in many parts of the world. The problems of parasitic helminthes becoming resistant to currently available anthelmintic drugs pose a challenge for the search - relying on natural products - for new and better anthelmintics. In this paper, four abundant Philippine weeds: Chrysopogon aciculatus Trin. Cyperus brevifolius Rottb., Ruellia tuberosa Linn. and Saccharum spontaneum Linn. were investigated for their anthelmintic activities to establish basis of their folkloric claim. The hexane-soluble and chloroform-soluble extracts were obtained through sequential solvent partitioning of the crude ethanolic extract of the air-dried aerial part of each plant sample. Meanwhile, the decoction was obtained from fresh aerial part of the plant samples. All extracts were then subjected to in vitro anthelmintic screening at different concentration as per method of Ghosh, et al. against African nightcrawler earthworms (Eudrillus euginiae) in which the activity of the extracts was determined by correlation with time. The anthelmintic bioassay results revealed a dose-dependent toxicity relationship. It indicated relatively low anthelmintic activities of the decoction of the four plant samples as compared to their corresponding crude ethanol extracts. Among the crude ethanol extracts, C. brevifolius (CBE) gave fastest time to bring about paralysis and death to the test organisms at all concentrations tested. For the hexane extracts, R. tuberosa (RTH) gave better activity among other plant samples. Lastly, among the chloroform-soluble extracts, both that of C. brevifolius (CBC) and R. tuberosa (RTC) comparably showed strongest anthelmintic activities at all tested concentrations, thus, exhibited best anthelmintic activity that is remarkably comparable to the positive control, Mebendazole at the highest concentration tested. In fact, CBC and RTC showed highest anthelmintic potential compared to all extracts tested in
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Energy Technology Data Exchange (ETDEWEB)
Chen, Shuangyan [Chinese Academy of Sciences (CAS), Institute of Botany (IB), Beijing; Huang, Xin [Chinese Academy of Sciences (CAS), Institute of Botany (IB), Beijing; Yang, Xiaohan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liu, Gongshe [Chinese Academy of Sciences (CAS), Institute of Botany (IB), Beijing
2013-07-04
BACKGROUND: Sheepgrass [Leymus chinensis (Trin.) Tzvel.] is an important perennial forage grass across the Eurasian Steppe and is known for its adaptability to various environmental conditions. However, insufficient data resources in public databases for sheepgrass limited our understanding of the mechanism of environmental adaptations, gene discovery and molecular marker development. RESULTS: The transcriptome of sheepgrass was sequenced using Roche 454 pyrosequencing technology. We assembled 952,328 high-quality reads into 87,214 unigenes, including 32,416 contigs and 54,798 singletons. There were 15,450 contigs over 500 bp in length. BLAST searches of our database against Swiss-Prot and NCBI non-redundant protein sequences (nr) databases resulted in the annotation of 54,584 (62.6%) of the unigenes. Gene Ontology (GO) analysis assigned 89,129 GO term annotations for 17,463 unigenes. We identified 11,675 core Poaceae-specific and 12,811 putative sheepgrass-specific unigenes by BLAST searches against all plant genome and transcriptome databases. A total of 2,979 specific freezing-responsive unigenes were found from this RNAseq dataset. We identified 3,818 EST-SSRs in 3,597 unigenes, and some SSRs contained unigenes that were also candidates for freezing-response genes. Characterizations of nucleotide repeats and dominant motifs of SSRs in sheepgrass were also performed. Similarity and phylogenetic analysis indicated that sheepgrass is closely related to barley and wheat. CONCLUSIONS: This research has greatly enriched sheepgrass transcriptome resources. The identified stress-related genes will help us to decipher the genetic basis of the environmental and ecological adaptations of this species and will be used to improve wheat and barley crops through hybridization or genetic transformation. The EST-SSRs reported here will be a valuable resource for future gene-phenotype studies and for the molecular breeding of sheepgrass and other Poaceae species.
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Obolewski, Krystian; Bąkowska, Martyna
2017-10-01
The species composition and abundance of epiphytic fauna inhabiting common reed (Phragmites australis (Cav.) Trin. ex Steud.) was performed in five coastal lakes in Słowiński National Park (southern Baltic coast in northern Poland). The lakes represent a salinity gradient (from freshwater to β-oligohaline waters) and four types of coastal lakes: (1) lagoon, L (Lake Łebsko, seawater enters it permanently); (2) coastal lake with periodically brackish water, CLB (Lake Gardno); (3) freshwater costal lake, CLF (Lake Smołdzińskie); and (4) coastal dune lakes, CLD (Dołgie Wielkie and Dołgie Małe). Using statistical ordination techniques, we found that the structure of epiphytic fauna (microinvertebrates and macroinvertebrates) is determined primarily by hydrological connectivity (water exchange) with the sea. Canonical Correspondence Analysis, coupled with variance partitioning, showed that hydrological connectivity accounted for 24% of the variation in the invertebrate community, followed by physico-chemical (19%) and trophic (8%) factors. Our results indicate that the assemblages of Ciliata-libera and Cnidaria are characteristic for L (β-oligohaline), Rotifera, Suctoria, Chaetogaster sp., Gastropoda and Trichoptera are characteristic for CLB (limnetic/β-oligohaline), but no taxonomic groups are characteristic for CLF and CLD (both limnetic). The index of multivariate dispersion showed a decreasing trend with the increasing lake isolation from the open sea, except for CLD. However, in terms of the structure of epiphytic fauna, Multi-Response Permutation Procedures showed that CLD significantly differed only from CLB. Our results suggest that the identified characteristic taxonomic groups of plant-associated macroinvertebrates have a high potential to be used as bioindicators of salinity and water exchange with the sea, due to their sensitivity to environmental stress.
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Chen, Shuangyan; Huang, Xin; Yan, Xueqing; Liang, Ye; Wang, Yuezhu; Li, Xiaofeng; Peng, Xianjun; Ma, Xingyong; Zhang, Lexin; Cai, Yueyue; Ma, Tian; Cheng, Liqin; Qi, Dongmei; Zheng, Huajun; Yang, Xiaohan; Li, Xiaoxia; Liu, Gongshe
2013-01-01
Sheepgrass [Leymus chinensis (Trin.) Tzvel.] is an important perennial forage grass across the Eurasian Steppe and is known for its adaptability to various environmental conditions. However, insufficient data resources in public databases for sheepgrass limited our understanding of the mechanism of environmental adaptations, gene discovery and molecular marker development. The transcriptome of sheepgrass was sequenced using Roche 454 pyrosequencing technology. We assembled 952,328 high-quality reads into 87,214 unigenes, including 32,416 contigs and 54,798 singletons. There were 15,450 contigs over 500 bp in length. BLAST searches of our database against Swiss-Prot and NCBI non-redundant protein sequences (nr) databases resulted in the annotation of 54,584 (62.6%) of the unigenes. Gene Ontology (GO) analysis assigned 89,129 GO term annotations for 17,463 unigenes. We identified 11,675 core Poaceae-specific and 12,811 putative sheepgrass-specific unigenes by BLAST searches against all plant genome and transcriptome databases. A total of 2,979 specific freezing-responsive unigenes were found from this RNAseq dataset. We identified 3,818 EST-SSRs in 3,597 unigenes, and some SSRs contained unigenes that were also candidates for freezing-response genes. Characterizations of nucleotide repeats and dominant motifs of SSRs in sheepgrass were also performed. Similarity and phylogenetic analysis indicated that sheepgrass is closely related to barley and wheat. This research has greatly enriched sheepgrass transcriptome resources. The identified stress-related genes will help us to decipher the genetic basis of the environmental and ecological adaptations of this species and will be used to improve wheat and barley crops through hybridization or genetic transformation. The EST-SSRs reported here will be a valuable resource for future gene-phenotype studies and for the molecular breeding of sheepgrass and other Poaceae species.
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Directory of Open Access Journals (Sweden)
Claudia Barchiesi-Ferrari
2011-06-01
Full Text Available Enzymatic in vitro digestibility has been studied as a method to predict energy values of forages for ruminants, although results have been affected by type of forage and methodological details of the technique. This work was performed to evaluate the effects of cellulase concentration (0.75, 1.0 and 6.25 g L-1, incubation time (24 or 48 h and type of final washing of the residue (water or acetone on the in vitro digestibility of the dry matter (DMD, organic matter (OMD and content of digestible organic matter in the DM (D value of silages made at three maturity stages from three types of pastures: a permanent pasture (Dactylis glomerata, Lolium perenne, Bromus catharticus Vahl var. catharticus, Trifolium repens and Holcus lanatus; b Italian ryegrass ley (Lolium multiflorum Lam. cv. Tama; c oats (Avena sativa L. and d mixed pasture (L. perenne-T. repens. Regression equations among cellulase results and in vitro values obtained with rumen fluid were also developed. Higher enzyme concentration, longer incubation time and final washing with acetone, resulted in a significant (P La digestibilidad enzimática in vitro ha sido estudiada para predecir el valor energético de forrajes para rumiantes, aunque el tipo de forraje y los detalles metodológicos han afectado los resultados obtenidos. Este trabajo pretende evaluar los efectos de la concentración de celulasa (0,75; 1,0 y 6,25 g L-1, tiempo de incubación (24 o 48 h y tipo de lavado final (agua o acetona del residuo, sobre la digestibilidad in vitro de la materia seca (DMD, materia orgánica (OMD y el contenido de materia orgánica digestible en la materia seca, o valor D (D value de ensilajes hechos con tres estados de madurez, de diferentes praderas: a pradera permanente (Dactylis glomerata, Lolium perenne, Bromus catharticus Vahl var. catharticus, Trifolium repens y Holcus lanatus; b ballica Italiana (Lolium multiflorum Lam. cv. Tama; c avena (Avena sativa L.; y d pradera mixta (L. perenne
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Histopatología de Ustilaginales (carbones) en Poaceas de los géneros Sorghum, Bromus y Glyceria
Astiz Gassó, Marta Mónica
2017-01-01
Sporisorium cruentum (Kühn.), es el agente causal de enfermedades en el género Sorghum incluyendo Sorghum halepense (L.) Pers.. El presente trabajo tuvo por objeto analizar el desarrollo y la evolución del patógeno en los tejidos del hospedante, y evaluar las implicancias de la enfermedad en el crecimiento vegetativo de los rizomas del sorgo de alepo. Para determinar la presencia del hongo se realizaron cortes histológicos del hospedante que se observaron por medio de microscopía óptica (MO) ...
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Gannon, Jill J.; Moore, Clinton T.; Shaffer, Terry L.; Flanders-Wanner, Bridgette
2011-01-01
Much of the native prairie managed by the U.S. Fish and Wildlife Service (Service) in the Prairie Pothole Region (PPR) is extensively invaded by the introduced cool-season grasses smooth brome (Bromus inermis) and Kentucky bluegrass (Poa pratensis). The central challenge to managers is selecting appropriate management actions in the face of biological and environmental uncertainties. We describe the technical components of a USGS management project, and explain how the components integrate and inform each other, how data feedback from individual cooperators serves to reduce uncertainty across the whole region, and how a successful adaptive management project is coordinated and maintained on a large scale. In partnership with the Service, the U.S. Geological Survey is developing an adaptive decision support framework to assist managers in selecting management actions under uncertainty and maximizing learning from management outcomes. The framework is built around practical constraints faced by refuge managers and includes identification of the management objective and strategies, analysis of uncertainty and construction of competing decision models, monitoring, and mechanisms for model feedback and decision selection. Nineteen Service field stations, spanning four states of the PPR, are participating in the project. They share a common management objective, available management strategies, and biological uncertainties. While the scope is broad, the project interfaces with individual land managers who provide refuge-specific information and receive updated decision guidance that incorporates understanding gained from the collective experience of all cooperators.
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Survival of a Rifampicin-Resistant Pseudomonas fluorescens Strain in Nine Mollisols
Directory of Open Access Journals (Sweden)
Tami L. Stubbs
2014-01-01
Full Text Available Pseudomonas fluorescens strain D7 (P.f. D7 is a naturally occurring soil bacterium that shows promise as a biological herbicide to inhibit growth of annual grass weeds, including downy brome (Bromus tectorum L., in crop- and rangelands. Pseudomonas fluorescens strain D7rif (P.f. D7rif is a rifampicin-resistant strain of P.f. D7. One of the greatest obstacles to successful biological weed control is survival of the organism under field conditions. Nine soils in the taxonomic order of Mollisols, collected from downy brome-infested areas of the Western and Central United States, were inoculated with P.f. D7rif and incubated in the laboratory to determine the effects of soil type, soil properties, incubation temperature, and soil water potential on survival of P.f. D7rif over 63 days. Silt loam soils from Lind, Washington, and Moro, Oregon, sustained the highest P.f. D7rif populations, and recovery was the lowest from Pendleton, Oregon soil. Survival and recovery of P.f. D7rif varied with soil type and temperature but not with the two soil water potentials tested. After 63 days, P.f. D7rif was recovered at levels greater than log 5.5 colony forming units (CFU g−1 soil from five of the nine test soils, a level adequate to suppress downy brome under field or range conditions.
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West, Amanda M.; Evangelista, Paul H.; Jarnevich, Catherine S.; Kumar, Sunil; Swallow, Aaron; Luizza, Matthew; Chignell, Steve
2017-01-01
Among the most pressing concerns of land managers in post-wildfire landscapes are the establishment and spread of invasive species. Land managers need accurate maps of invasive species cover for targeted management post-disturbance that are easily transferable across space and time. In this study, we sought to develop an iterative, replicable methodology based on limited invasive species occurrence data, freely available remotely sensed data, and open source software to predict the distribution of Bromus tectorum (cheatgrass) in a post-wildfire landscape. We developed four species distribution models using eight spectral indices derived from five months of Landsat 8 Operational Land Imager (OLI) data in 2014. These months corresponded to both cheatgrass growing period and time of field data collection in the study area. The four models were improved using an iterative approach in which a threshold for cover was established, and all models had high sensitivity values when tested on an independent dataset. We also quantified the area at highest risk for invasion in future seasons given 2014 distribution, topographic covariates, and seed dispersal limitations. These models demonstrate the effectiveness of using derived multi-date spectral indices as proxies for species occurrence on the landscape, the importance of selecting thresholds for invasive species cover to evaluate ecological risk in species distribution models, and the applicability of Landsat 8 OLI and the Software for Assisted Habitat Modeling for targeted invasive species management.
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Biotic soil crusts in relation to topography, cheatgrass, and fire in the Columbia Basin, Washington
Ponzetti, Jeanne; McCune, B.; Pyke, David A.
2007-01-01
We studied lichen and bryophyte soil crust communities in a large public grazing allotment within a sagebrush steppe ecosystem in which the biotic soil crusts are largely intact. The allotment had been rested from grazing for 12 years, but experienced an extensive series of wildfires. In the 350, 4 ?? 0.5 m plots, stratified by topographic position, we found 60 species or species groups that can be distinguished in the field with a hand lens, averaging 11.5 species groups per plot. Lichen and bryophyte soil crust communities differed among topographic positions. Draws were the most disturbed, apparently from water erosion in a narrow channel and mass wasting from the steepened sides. Presumably because of this disturbance, draws had the lowest average species richness of all the topographic strata we examined. Biotic crust species richness and cover were inversely related to cover of the invasive annual, cheatgrass (Bromus tectorum), and positively related to cover of native bunchgrasses. Integrity of the biotic crust was more strongly related to cheatgrass than to fire. In general, we observed good recovery of crusts following fire, but only in those areas dominated by perennial bunchgrasses. We interpret the resilience of the biotic crust, in this case, to the low abundance of cheatgrass, low amounts of soil disturbance and high moss cover. These fires have not resulted in an explosion of the cheatgrass population, perhaps because of the historically low levels of livestock grazing.
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Bradley, Bethany A; Mustard, John F
2006-06-01
Improved understanding of the spatial dynamics of invasive plant species may lead to more effective land management and reduced future invasion. Here, we identified the spatial extents of nonnative cheatgrass (Bromus tectorum) in the north central Great Basin using remotely sensed data from Landsat MSS, TM, and ETM+. We compared cheatgrass extents in 1973 and 2001 to six spatially explicit landscape variables: elevation, aspect, hydrographic channels, cultivation, roads, and power lines. In 2001, Cheatgrass was 10% more likely to be found in elevation ranges from 1400 to 1700 m (although the data suggest a preferential invasion into lower elevations by 2001), 6% more likely on west and northwest facing slopes, and 3% more likely within hydrographic channels. Over this time period, cheatgrass expansion was also closely linked to proximity to land use. In 2001, cheatgrass was 20% more likely to be found within 3 km of cultivation, 13% more likely to be found within 700 m of a road, and 15% more likely to be found within 1 km of a power line. Finally, in 2001 cheatgrass was 26% more likely to be present within 150 m of areas occupied by cheatgrass in 1973. Using these relationships, we created a risk map of future cheatgrass invasion that may aid land management. These results highlight the importance of including land use variables and the extents of current plant invasion in predictions of future risk.
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Kleinhesselink, Andrew R; Magnoli, Susan M; Cushman, J Hall
2014-08-01
Ecosystem-engineering plants modify the physical environment and can increase species diversity and exotic species invasion. At the individual level, the effects of ecosystem engineers on other plants often become more positive in stressful environments. In this study, we investigated whether the community-level effects of ecosystem engineers also become stronger in more stressful environments. Using comparative and experimental approaches, we assessed the ability of a native shrub (Ericameria ericoides) to act as an ecosystem engineer across a stress gradient in a coastal dune in northern California, USA. We found increased coarse organic matter and lower wind speeds within shrub patches. Growth of a dominant invasive grass (Bromus diandrus) was facilitated both by aboveground shrub biomass and by growing in soil taken from shrub patches. Experimental removal of shrubs negatively affected species most associated with shrubs and positively affected species most often found outside of shrubs. Counter to the stress-gradient hypothesis, the effects of shrubs on the physical environment and individual plant growth did not increase across the established stress gradient at this site. At the community level, shrub patches increased beta diversity, and contained greater rarified richness and exotic plant cover than shrub-free patches. Shrub effects on rarified richness increased with environmental stress, but effects on exotic cover and beta diversity did not. Our study provides evidence for the community-level effects of shrubs as ecosystem engineers in this system, but shows that these effects do not necessarily become stronger in more stressful environments.
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Directory of Open Access Journals (Sweden)
Dorin-Benone Pleşa
2012-05-01
Full Text Available Lately it is a high interest in the establishing of temporary grasslands, these being considered a valuable source of fodder from the quantitative and qualitative point of view. Temporary grasslands can be established instead of degraded permanent grasslands or in arable lands. In the paper are presented the results of the research which took place in 2010 and 2011, regarding the fodder evolution of a double factor experience; A factor – mixtures (8 complex mixtures of perennial grasses and legumes and one alfalfa pure crop, considered as a witness,B factor – levels of fertilization (0N0P2O5, 60N70P2O5,120N70P2O5 kg·ha-1. In 2010 the highest productions (13.16 SU t·ha-1 were obtained at all the cycles from the 5th mixture composed from red clover and 4 species of grasses Trifolium pratense L., Dactylis glomerata L., Festulolium Asch. & Graebn., Phleum pratense L., Lolium perenne L.. In 2011, mixture number 3, recognized as being recommended for the forest steppe area and composed from Lotus corniculatus L.,Onobrychis viciifolia Scop., Dactylis glomerata L., Festuca pratensis Huds., Bromus inermis Leyss, presented the highest productions (4.82 t·ha-1 for the 60N70P2O5 and 120N70P2O5 kg·ha-1 levels of fertilization.
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Directory of Open Access Journals (Sweden)
M. Borhani
2016-05-01
Full Text Available In order to investigate the effects of range management plans on species diversity, richness and evenness in Semirum rangelands, 52 sites (28 with treated plan and 24 without treated plan were selected. The non-parametric indices for species richness (Margalof, Menhinick, Jacknife and counting method and species diversity (Simpson, Camargo, Smith and Wilson and modified Nee were compared in two management plans. The mean comparisons were made by independent T Student Test and Mann-Witheny U Test, and correlation was determined between diversity indices and vegetation parameters. Based on the results there was no significant difference between the two management systems regarding environmental features, while the implementation of range management plans caused significant reduction of stocking rate. Among the studied indices, evenness of species in sites without treated plan was significantly more than the sites with treated plan. The correlation matrix showed that there was a significant positive correlation between species richness and vegetation cover, production of perennial plans, and the rangeland condition and trend, while evenness showed significant negative correlation with these indices. Generally, implementation of range management plans has considerable effect on increasing climax species, dominance of Bromus tomentellus and it causes improvement of rangeland condition and reduction of evenness. This behavior could be explained by the balance between species competition and grazing pressure. Further, succession process of the studied communities demonstrates domination of some desirable species, high production and less diversity.
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Recovery of 15N-labelled fertilizers applied to bromegrass on a thin black chernozem soil
International Nuclear Information System (INIS)
Malhi, S.S.
1995-01-01
The availability of N fertilizers on established grass stands is a function of such processes as immobilization, gaseous loss, leaching and position of applied N. A field experiment was conducted on a Thin Black Chernozem soil at Crossfield, Alberta to determine the effect of source, time and method of application on the recovery of 15 N-labelled fertilizers applied to smooth bromegrass (Bromus inermis Leyss.). The treatments included two sources of N [urea and ammonium nitrate (AN)], four application times (early autumn, late autumn, early spring and late spring) and two methods of placement (surface-broadcast and subsurface banding). In most cases the 15 N recovery in soil did not differ much between urea and AN. However, when urea was surface-broadcast, there was, on average, 10.2% less 15 N recovery in plants than AN. The N recovery for late spring > early spring > late autumn = early autumn. When urea was banded 4 cm deep into the soil, N recovery in plants increased significantly compared with its surface-broadcast application. However, this was not observed when the source of N was AN. Banding generally increased the amount of immobilized N present in the soil and N recovery. We concluded that the N recovery in plants and in plants plus soil was less for urea than for AN and was less with autumn broadcast N application than with spring broadcast application. (author). 23 refs., 3 tabs
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Revisiting the Life Cycle of Dung Fungi, Including Sordaria fimicola.
Newcombe, George; Campbell, Jason; Griffith, David; Baynes, Melissa; Launchbaugh, Karen; Pendleton, Rosemary
2016-01-01
Dung fungi, such as Sordaria fimicola, generally reproduce sexually with ascospores discharged from mammalian dung after passage through herbivores. Their life cycle is thought to be obligate to dung, and thus their ascospores in Quaternary sediments have been interpreted as evidence of past mammalian herbivore activity. Reports of dung fungi as endophytes would seem to challenge the view that they are obligate to dung. However, endophyte status is controversial because surface-sterilization protocols could fail to kill dung fungus ascospores stuck to the plant surface. Thus, we first tested the ability of representative isolates of three common genera of dung fungi to affect plant growth and fecundity given that significant effects on plant fitness could not result from ascospores merely stuck to the plant surface. Isolates of S. fimicola, Preussia sp., and Sporormiella sp. reduced growth and fecundity of two of three populations of Bromus tectorum, the host from which they had been isolated. In further work with S. fimicola we showed that inoculations of roots of B. tectorum led to some colonization of aboveground tissues. The same isolate of S. fimicola reproduced sexually on inoculated host plant tissues as well as in dung after passage through sheep, thus demonstrating a facultative rather than an obligate life cycle. Finally, plants inoculated with S. fimicola were not preferred by sheep; preference had been expected if the fungus were obligate to dung. Overall, these findings make us question the assumption that these fungi are obligate to dung.
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Epanchin-Niell, Rebecca; Englin, Jeffrey; Nalle, Darek
2009-01-01
In large areas of the arid western United States, much of which are federally managed, fire frequencies and associated management costs are escalating as flammable, invasive cheatgrass (Bromus tectorum) increases its stronghold. Cheatgrass invasion and the subsequent increase in fire frequency result in the loss of native vegetation, less predictable forage availability for livestock and wildlife, and increased costs and risk associated with firefighting. Revegetation following fire on land that is partially invaded by cheatgrass can reduce both the dominance of cheatgrass and its associated high fire rate. Thus restoration can be viewed as an investment in fire-prevention and, if native seed is used, an investment in maintaining native vegetation on the landscape. Here we develop and employ a Markov model of vegetation dynamics for the sagebrush steppe ecosystem to predict vegetation change and management costs under different intensities and types of post-fire revegetation. We use the results to estimate the minimum total cost curves for maintaining native vegetation on the landscape and for preventing cheatgrass dominance. Our results show that across a variety of model parameter possibilities, increased investment in post-fire revegetation reduces long-term fire management costs by more than enough to offset the costs of revegetation. These results support that a policy of intensive post-fire revegetation will reduce long-term management costs for this ecosystem, in addition to providing environmental benefits. This information may help justify costs associated with revegetation and raise the priority of restoration in federal land budgets.
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Effects of competition on induction of crassulacean acid metabolism in a facultative CAM plant.
Yu, Kailiang; D'Odorico, Paolo; Li, Wei; He, Yongli
2017-06-01
Abiotic drivers of environmental stress have been found to induce CAM expression (nocturnal carboxylation) in facultative CAM species such as Mesembryanthemum crystallinum. The role played by biotic factors such as competition with non-CAM species in affecting CAM expression, however, remains largely understudied. This research investigated the effects of salt and water conditions on the competition between M. crystallinum and the C 3 grass Bromus mollis with which it is found to coexist in California's coastal grasslands. We also investigated the extent to which CAM expression in M. crystallinum was affected by the intensity of the competition with B. mollis. We found that M. crystallinum had a competitive advantage over B. mollis in drought and saline conditions, while B. mollis exerted strong competitive effects on M. crystallinum in access to light and soil nutrients in high water conditions. This strong competitive effect even outweighed the favorable effects of salt or water additions in increasing the biomass and productivity of M. crystallinum in mixture. Regardless of salt conditions, M. crystallinum did not switch to CAM photosynthesis in response to this strong competitive effect from B. mollis. Disturbance (i.e., grass cutting) reduced the competitive pressure by B. mollis and allowed for CAM expression in M. crystallinum when it was grown mixed with B. mollis. We suggest that moderate competition with other functional groups can enhance CAM expression in M. crystallinum, thereby affecting its plasticity and ability to cope with biological stress.
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Directory of Open Access Journals (Sweden)
César Augusto Castro
2009-01-01
Full Text Available Diversas concepções estabelecidas entre a leitura, o texto e o leitor são aqui analisadas. Para isso, o ponto de partida é uma perspectiva sócio-histórica, tratando de compreender as estratégias, o desenvolvimento e as transformações nas diversas apropriações da produção cultural e sua influência na formação leitora. Destacam-se alguns dos fatores que intervêm na manipulação dos suportes culturais, expondo as diversas modificações a que foram sujeitadas as formas de ler, as apropriações do sentido dos textos, a produção dos impressos e sua representação no tecido societal. Conclui-se com a situação em que o Maranhão se encontra em relação às práticas leitoras, à literatura, ao livro didático e às formas de ler no contexto escolar e não escolar, destacando a importância que as crenças, as intenções, as atitudes, as expectativas sobre a leitura têm, seja por parte do aluno, seja por parte do professor, para uma prática inovadora na formação leitora e nas diferentes situações do ato de ler.Different conceptions established among the reading, the text and the reader are analyzed here. For this, the starting point is a social-historical perspective, trying to understand the strategies, the development and the transformations in the various appropriations of the cultural production and its influence in the reader formation. Some factors of the manipulation of the cultural supports are highlighted, displaying the various modifications the forms of reading have been subjected; , the appropriations of the meaning of the texts, the production of printed materials and their representation in the society. We conclude with the situation of the state of Maranhão in relation to the practice of reading, literature, the didactic book and the forms of reading in the school and not in the school context, showing the importance that the beliefs, the intentions, the attitudes and the expectations on the reading process have, either on the part of the pupil, or the teacher, for a practical innovation in the reading formation and the different situations of the act of reading.
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Directory of Open Access Journals (Sweden)
Claudia Barchiesi-Ferrari
2011-06-01
Full Text Available In pasture-based dairy herds where silage is a widely adopted supplement, optimized feeding requires reliable estimations of nutritional quality of this conserved forage. Metabolizable energy, an important nutritional fraction, can be predicted from digestibility-related traits, such as the digestible organic matter contained in the dry matter (D-value. The aim of the present study was to evaluate the prediction of D-value and dry matter digestibility (DMD of grass silages made from four different pastures and maturity stages, using the pepsin-cellulase method. Fungal cellulase was used, applying different enzyme concentrations, incubation times and types of final wash. The silages were prepared from permanent pasture (Dactylis glomerata L., Lolium perenne L., Bromus catharticus Vahl var. catharticus, Trifolium repens L. and Holcus lanatus L., rotation pasture (Lolium multiflorum Lam. cv. Tama, oats (Avena sativa L., and mixed pasture (L. perenne-T. repens. These were harvested at three different physiological stages (vegetative, ear emergence and dough grain. The treatment using an incubation time of 24 h, a cellulase concentration of 6.25 g L-1 and final wash with water (Treatment 3 presented the best prediction capacity of the in vivo D-value (R² = 0.78 and in vivo DMD (R² = 0.71. In vivo D-value prediction improved (R² = 0.8 when a chemical determination (crude fibre, gross energy, neutral detergent fibre, total ash or acid detergent fibre was included in addition (multiple regression to D-value obtained with cellulases (Treatment 3. Results of DMD obtained with cellulases show good precision, but underestimate in vivo values, and are closer to those obtained with ruminal fluid. Suitable equations could be used to improve accuracy.En sistemas lecheros pastoriles que utilizan ensilaje como suplemento, se requiere conocer el valor nutricional de éste para optimizar la alimentación del ganado. La energía metabolizable, importante fracci
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Knutson, Kevin C.; Pyke, David A.; Wirth, Troy A.; Pilliod, David S.; Brooks, Matthew L.; Chambers, Jeanne C.
2009-01-01
Department of the Interior (DOI) bureaus have invested heavily (for example, the U.S. Bureau of Land Management (BLM) spent more than $60 million in fiscal year 2007) in seeding vegetation for emergency stabilization and burned area rehabilitation of non-forested arid lands over the past 10 years. The primary objectives of these seedings commonly are to (1) reduce the post-fire dominance of non-native annual grasses, such as cheatgrass (Bromus tectorum) and red brome (Bromus rubens); (2) minimize the probability of recurrent fire; and (3) ultimately produce desirable vegetation characteristics (for example, ability to recover following disturbance [resilience], resistance to invasive species, and a capacity to support a diverse flora and fauna). Although these projects historically have been monitored to varying extents, land managers currently lack scientific evidence to verify whether seeding arid and semiarid lands achieves desired objectives. Given the amount of resources dedicated to post-fire seeding projects, a synthesis of information determining the factors that result in successful treatments is critically needed. Although results of recently established experiments and monitoring projects eventually will provide useful insights for the future direction of emergency stabilization and burned area rehabilitation programs, a chronosequence approach evaluating emergency stabilization and burned area rehabilitation treatments (both referenced hereafter as ESR treatments) over the past 30 years could provide a comprehensive assessment of treatment success across a range of regional environmental gradients. By randomly selecting a statistically robust sample from the population of historic ESR treatments in the Intermountain West, this chronosequence approach would have inference for most ecological sites in this region. The goal of this feasibility study was to compile and examine historic ESR records from BLM field offices across the Intermountain West to
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Palta, Şahin; Lermi, Ayşe Genç; Beki, Rıdvan
2016-06-01
The object of the present research was to establish correlations between the status of root colonization of arbuscular mycorrhizal fungi (AMF) and different types of land use. In order to achieve this aim, rhizosphere soil samples from grassland crops were taken during June and July of 2013 in order to use for determining several soil characteristics. The 27 different taxa and 60 soil samples were collected from the rhizosphere level in the study areas. The existence of AMF was confirmed in 100 % of these plants with different rations of colonization (approximately 12-89 %). Bromus racemosus L. (pasture) was the most dense taxon with the percentage of AMF colonization of 88.9 %, and Trifolium pratense L. (forest) was the least dense taxon with the percentage of AMF colonization of 12.2 % (average 52.0 %). As a result of the statistical analysis, a positive relationship was found between the botanical composition of legumes and AMF colonization (r = 0.35; p = 0.006). However, a negative relationship was determined between botanical composition of other plant families and AMF colonization (r = -0.39; p = 0.002). In addition, a positive relationship was defined between soil pH (H2O) and the root colonization of AMF (r = 0.35; p = 0.005). The pasture had the highest mean value of AMF root colonization. However, the pasture and gap in the forest were in the same group, according to the results of the S-N-K test.
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Plant growth and trace-element uptake on acidic coal refuse amended with lime or fly ash
Energy Technology Data Exchange (ETDEWEB)
Jastrow, J.D. (Argonne National Lab., IL); Zimmerman, C.A.; Dvorak, A.J.; Hinchman, R.R.
1981-04-01
Two commonly used revegetation species, Kentucky 31 tall fescue (Festuca arundinacea Schreb.) and Lincoln smooth brome (Bromus inermis Leyss.), were grown for 60 days in pots containing coarse coal mine refuse (referred to as gob, pH = 3.5) amended with either lime or alkaline powerplant fly ash. Both species were also grown in pots containing a silt loam surface soil as a control. Morphological growth parameters were measured over time; dry weights and shoot/root ratios were determined at harvest. Concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn in the plant shoots were determined by atomic absorption spectrophotometry. Plant growth of both species was not as good on either lime- or fly ash-amended gob as it was on surface soil; however, more vigorous growth occurred on lime-amended gob than on fly ash-amended gob. Significant differences (rho < 0.05) in the tissue concentrations of Cd, Co, Fe, Hg, Mn, Pb, V, and Zn were found among the plants grown on the three substrates. Except for Hg and Pb, these elements were higher in plants grown on at least one of the amended-gob substrates than in plants grown on surface soil. Significant substrate differences were not observed for Al, As, Cr, Cu, Ni, and Se. The tissue concentrations of some elements - notably Al, Cu, Fe, Mn, V, and Zn - were high enough in plants from one or more of the substrates to either approach or exceed concentrations which have been reported to be associated with toxic effects in some plant species.
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Bird-habitat relationships in interior Columbia Basin shrubsteppe
Earnst, S.L.; Holmes, A.L.
2012-01-01
Vegetation structure is considered an important habitat feature structuring avian communities. In the sagebrush biome, both remotely-sensed and field-acquired measures of big sagebrush (Artemisia tridentata) cover have proven valuable in understanding avian abundance. Differences in structure between the exotic annual cheatgrass (Bromus tectorum) and native bunchgrasses are also expected to be important. We used avian abundance data from 318 point count stations, coupled with field vegetation measurements and a detailed vegetation map, to model abundance for four shrub- and four grassland-associated avian species in southeastern Washington shrubsteppe. Specifically, we ask whether species distinguish between bunchgrass and cheatgrass, and whether mapped, categorical cover types adequately explain species' abundance or whether fine-grained, field-measured differences in vegetation cover are also important. Results indicate that mapped cover types alone can be useful for predicting patterns of distribution and abundance within the sagebrush biome for several avian species (five of eight studied here). However, field-measured sagebrush cover was a strong positive predictor for Sage Sparrow (Amphispiza belli), the only sagebrush obligate in this study, and a strong negative predictor for two grassland associates, Horned Lark (Eremophila alpestris) and Grasshopper Sparrow (Ammodramus savannarum). Likewise, shrub associates did not differ in abundance in sagebrush with a cheatgrass vs. bunchgrass understory, but grassland associates were more common in either bunchgrass (Horned Lark and Grasshopper Sparrow) or cheatgrass grasslands (Long-billed Curlew, Numenius americanus), or tended to use sagebrush-cheatgrass less than sagebrush-bunchgrass (Horned Lark, Grasshopper Sparrow, and Savannah Sparrow, Passerculus sandwichensis).
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Directory of Open Access Journals (Sweden)
Scott Abella
2015-06-01
Full Text Available Globally, invasion by non-native plants threatens resources that nature reserves are designated to protect. We assessed the status of non-native plant invasion on 1,662, 0.1-ha plots in Death Valley National Park, Mojave National Preserve, and Lake Mead National Recreation Area. These parks comprise 2.5 million ha, 23% of the national park land in the contiguous USA. At least one non-native species inhabited 82% of plots. Thirty-one percent of plots contained one non-native species, 30% two, 17% three, and 4% four to ten non-native species. Red brome (Bromus rubens, an ‘ecosystem engineer’ that alters fire regimes, was most widespread, infesting 60% of plots. By identifying frequency of species through this assessment, early detection and treatment can target infrequent species or minimally invaded sites, while containment strategies could focus on established invaders. We further compared two existing systems for prioritizing species for management and found that a third of species on plots had no rankings available. Moreover, rankings did not always agree between ranking systems for species that were ranked. Presence of multiple non-native species complicates treatment, and while we found that 40% of plots contained both forb and grass invaders, exploiting accelerated phenology of non-natives (compared to native annuals might help manage multi-species invasions. Large sizes of these parks and scale of invasion are formidable challenges for management. Yet, precisely because of their size, these reserves represent opportunities to conserve large landscapes of native species by managing non-native plant invasions.
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González, Eduardo; Sher, Anna A.; Anderson, Robert M.; Bay, Robin F.; Bean, Daniel W.; Bissonnete, Gabriel J.; Cooper, David J.; Dohrenwend, Kara; Eichhorst, Kim D.; El Waer, Hisham; Kennard, Deborah K.; Harms-Weissinger, Rebecca; Henry, Annie L.; Makarick, Lori J.; Ostoja, Steven M.; Reynolds, Lindsay V.; Robinson, W. Wright; Shafroth, Patrick B.; Tabacchi, Erich
2017-01-01
Control of invasive species within ecosystems may induce secondary invasions of non-target invaders replacing the first alien. We used four plant species listed as noxious by local authorities in riparian systems to discern whether 1) the severity of these secondary invasions was related to the control method applied to the first alien; and 2) which species that were secondary invaders persisted over time. In a collaborative study by 16 research institutions, we monitored plant species composition following control of non-native Tamarix trees along southwestern U.S. rivers using defoliation by an introduced biocontrol beetle, and three physical removal methods: mechanical using saws, heavy machinery, and burning in 244 treated and 79 untreated sites across six U.S. states. Physical removal favored secondary invasions immediately after Tamarix removal (0–3 yrs.), while in the biocontrol treatment, secondary invasions manifested later (> 5 yrs.). Within this general trend, the response of weeds to control was idiosyncratic; dependent on treatment type and invader. Two annual tumbleweeds that only reproduce by seed (Bassia scoparia and Salsola tragus) peaked immediately after physical Tamarix removal and persisted over time, even after herbicide application. Acroptilon repens, a perennial forb that vigorously reproduces by rhizomes, and Bromus tectorum, a very frequent annual grass before removal that only reproduces by seed, were most successful at biocontrol sites, and progressively spread as the canopy layer opened. These results demonstrate that strategies to control Tamarix affect secondary invasions differently among species and that time since disturbance is an important, generally overlooked, factor affecting response.
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Soto-Navarro, S A; Knight, M H; Lardy, G P; Bauer, M L; Caton, J S
2004-12-01
Six Angus crossbred cow-calf pairs (653 +/- 35 kg and 157 +/- 10 kg initial BW for cows and calves, respectively) were used to evaluate the influence of a fiber-based creep feed on intake, ruminal fermentation, digestion characteristics, and microbial efficiency in nursing beef calves. Cow-calf pairs were stratified by calf age and assigned randomly to one of two treatments: control (no supplement) or supplemented. Supplemented calves received 0.9 kg of a 49% soy hulls, 44% wheat middlings, 6% molasses, and 1% limestone supplement (DM basis) daily. All calves were cannulated in the rumen and duodenum and given ad libitum access to chopped brome hay (Bromus inermus L; 7.43% CP, 40.96% ADF, and 63.99% NDF; DM basis). Supplementation was initiated on May 1 (88 +/- 10.3 d calf age). Three sampling periods were conducted throughout the study (June 14 to 25, July 5 to 16, and August 9 to 20). Supplement and forage were offered at 0800 daily. Total, hay, and milk OM intakes of nursing calves were not affected by supplementation (2,014 vs. 2,328 +/- 288.8, 1,486 vs. 1,029 +/- 3,06.9, and 528 vs. 575 +/- 87.0 g/d, respectively). Milk OM intake was less (P 0.40) total-tract OM digestibility during June and August; however, during July, total-tract OM digestibility was lower (P = 0.03) for the control calves. Ruminal ammonia concentration, total VFA, and butyrate molar proportion increased (P effects on OM intake, total-tract OM digestibility, and ruminal fermentation characteristics in nursing beef calves.
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Revisiting the Life Cycle of Dung Fungi, Including Sordaria fimicola.
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George Newcombe
Full Text Available Dung fungi, such as Sordaria fimicola, generally reproduce sexually with ascospores discharged from mammalian dung after passage through herbivores. Their life cycle is thought to be obligate to dung, and thus their ascospores in Quaternary sediments have been interpreted as evidence of past mammalian herbivore activity. Reports of dung fungi as endophytes would seem to challenge the view that they are obligate to dung. However, endophyte status is controversial because surface-sterilization protocols could fail to kill dung fungus ascospores stuck to the plant surface. Thus, we first tested the ability of representative isolates of three common genera of dung fungi to affect plant growth and fecundity given that significant effects on plant fitness could not result from ascospores merely stuck to the plant surface. Isolates of S. fimicola, Preussia sp., and Sporormiella sp. reduced growth and fecundity of two of three populations of Bromus tectorum, the host from which they had been isolated. In further work with S. fimicola we showed that inoculations of roots of B. tectorum led to some colonization of aboveground tissues. The same isolate of S. fimicola reproduced sexually on inoculated host plant tissues as well as in dung after passage through sheep, thus demonstrating a facultative rather than an obligate life cycle. Finally, plants inoculated with S. fimicola were not preferred by sheep; preference had been expected if the fungus were obligate to dung. Overall, these findings make us question the assumption that these fungi are obligate to dung.
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Segetal flora of cereal crop agrocenoses in the Suwałki Landscape Park
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Matusiewicz Marta
2016-06-01
Full Text Available Segetal flora of cereal crop agrocenoses in the Suwałki Landscape Park was studied in between the years 2012 and 2013. One hundred phytosociological Braun-Blanquet releves were taken, documenting the occurrence of 152 species of vascular plants that represented 29 botanic families. Analysis of the contributions of geographic-historical groups revealed the dominance of the native species, apophytes (87 species, making 57.2%, over anthropophytes (65 species, 42.8%. The number of short-lived species was twice greater (103 species, 67.8% than the perennial ones (49 species, 32.2%. As regards the lifeforms, the therophytes were dominant (96 species, 63.2% over hemicryptophytes (44 species, 28.9% and geophytes (12 species, 7.9%. Among the species of segetal flora in the area studied, 23 valuable species classified to different categories of protection, were identified. The presence of Consolida regalis, Centaurea cyanus and Bromus secalinus, belonging to threatened species in other regions of Poland, was abundant. Also the species: Anthemis tinctoria, Echium vulgare and Anchusa officinalis were met with high frequency. The species: Agrostemma githago, Papaver argemone and Papaver dubium were represented by single plants, which can suggest their dying out. In the Park area, expansive species, threatening the biodiversity, such as Myosotis arvensis, Viola arvensis, Galeopsis tetraehit, Stellaria media, Artemisia vulgaris, Galinsoga parviflora, Elymus repens, Capsella bursa pastoris, Erodium cicutarium, Chamomilla recutita, Matricaria maritima subsp. inodora, Convolvulus arvensis, Polygonum persicaria, Polygonum lapathifolium subsp. pallidum and Polygonum lapathifolium subsp. lapathifolium, were commonly seen in the crop land.
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Goergen, Erin; Chambers, Jeanne C
2012-01-01
In semi-arid ecosystems, heterogeneous resources can lead to variable seedling recruitment. Existing vegetation can influence seedling establishment by modifying the resource and physical environment. We asked how a native legume, Lupinus argenteus, modifies microenvironments in unburned and burned sagebrush steppe, and if L. argenteus presence facilitates seedling establishment of native species and the non-native annual grass, Bromus tectorum. Field treatments examined mechanisms by which L. argenteus likely influences establishment: (1) live L. argenteus; (2) dead L. argenteus; (3) no L. argenteus; (4) no L. argenteus with L. argenteus litter; (5) no L. argenteus with inert litter; and (6) mock L. argenteus. Response variables included soil nitrogen, moisture, temperature, solar radiation, and seedling establishment of the natives Elymus multisetus and Eriogonum umbellatum, and non-native B. tectorum. In both unburned and burned communities, there was higher spring soil moisture, increased shade and reduced maximum temperatures under L. argenteus canopies. Adult L. argenteus resulted in greater amounts of soil nitrogen (N) only in burned sagebrush steppe, but L. argenteus litter increased soil N under both unburned and burned conditions. Although L. argenteus negatively affected emergence and survival of B. tectorum overall, its presence increased B. tectorum biomass and reproduction in unburned plots. However, L. argenteus had positive facilitative effects on size and survival of E. multisetus in both unburned and burned plots. Our study indicates that L. argenteus can facilitate seedling establishment in semi-arid systems, but net effects depend on the species examined, traits measured, and level of abiotic stress.
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Nemec, Kristine T.; Allen, Craig R.; Helzer, Christopher J.; Wedin, David A.
2013-01-01
In recent years, agricultural producers and non-governmental organizations and agencies have restored thousands of hectares of cropland to grassland in the Great Plains of the United States. However, little is known about the relationships between richness and seeding density in these restorations and resistance to invasive plant species. We assessed the effects of richness and seeding density on resistance to invasive and other unseeded plant species in experimental tallgrass prairie plots in central Nebraska. In 2006, twenty-four 55 m × 55 m plots were planted with six replicates in each of four treatments: high richness (97 species typically planted by The Nature Conservancy), at low and high seeding densities, and low richness (15 species representing a typical Conservation Reserve Program mix, CP25), at low and high seeding densities. There was a significant negative relationship between richness and basal cover of unseeded perennial forbs/legumes and unseeded perennial/annual grasses, abundance of bull thistle (Cirsium vulgare), and the number of inflorescences removed from smooth brome (Bromus inermis) transplants. Invasion resistance may have been higher in the high richness treatments because of the characteristics of the dominant species in these plots or because of greater interspecific competition for limiting resources among forbs/legumes with neighboring plants belonging to the same functional group. Seeding density was not important in affecting invasion resistance, except in the cover of unseeded grasses. Increasing seed mix richness may be more effective than increasing the seeding density for decreasing invasion by unseeded perennial species, bull thistle, and smooth brome.
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Sediment remediation treatment techniques for the Venice industrial canals
Energy Technology Data Exchange (ETDEWEB)
Pippa, R.; Scanferla, P.; Cammarata, F.; Zampieri, L.; Carlon, C. [Consorzio Venezia Ricerche (Italy); Pavoni, B. [Ca' Foscari University of Venice (Italy). Dept. of Environmental Sciences; Pannocchia, G. [Venezia Technologie SpA, Venice (Italy); Hreglich, S. [Stazione Sperimentale del Vetro, Venice (Italy); Avezzu, F. [Depuracque Impianti srl, Venice (Italy)
2003-07-01
The main objective of SeRTech project (Sediment Remediation Technologies) is to develop an integrated cost-effective treatment system to address heterogeneous contamination and matrixes, such as those of Venice lagoon dredged materials. Seven treatment techniques, selected over a large array, have been tested: Thermal Desorption. A preliminary set of isothermal treatments at different temperatures was performed to evaluated the losses of organic and the most volatile metals (such as Pb and As). An almost full volatilisation of organic compounds was observed at temperatures ranging between 200 and 300 C. Chemical stabilization-solidification. Depuracque Impianti srl process uses innovative patented additives (polimers and superplasticizers) to immobilize heavy metals into cement pellets. Solvent extraction. Organic contaminants such as PAHs and PCBs were extracted from sediments by using ethyl acetate. The results showed that solvent extraction obtained high efficiency in removal of PAHs and other organic contaminants. Immobilization of heavy metals employing sulfate-reducing bacteria. High Gradient Magnetic Separation (HGMS). Sulfate reducing bacteria (SBR) produce an iron sulfide containing biomass with a high capability to adsorbe hevy metals and some organic compounds. This biomass can be separated through a high gradient magnetic field removing a substantial fraction of contaminants. Vitrification. Sediment was mixed with other inorganic wastes (glass cullet, feldsphatic tailings) and low amounts of row material to obtain an inert glass, which in turn can be recycled into other useful products, for example glass fibres, foam glass and glass ceramics. Phytoremediation. Phragmites australis (Cav.), Trin; Juncus Iacustrus, Arthrocnmemum fruticosum, Spartina maritima, Helianthus annuus L., Zea mais L., Brassica napus L., Brassica juncea L. have been selected to verify limit and efficiency of phytoextraction for heavy metals (Zn, Pb, Hg, Cd, As, Ni). Not only
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Bu, Chongfeng; Wu, Shufang; Han, Fengpeng; Yang, Yongsheng; Meng, Jie
2015-01-01
Biological soil crusts (BSCs, or biocrusts) have important positive ecological functions such as erosion control and soil fertility improvement, and they may also have negative effects on soil moisture in some cases. Simultaneous discussions of the two-sided impacts of BSCs are key to the rational use of this resource. This study focused on the contribution of BSCs while combining with specific types of vegetation to erosion reduction and their effects on soil moisture, and it addressed the feasibility of removal or raking disturbance. Twelve plots measuring 4 m × 2 m and six treatments (two plots for each) were established on a 15° slope in a small watershed in the Loess Plateau using BSCs, bare land (as a control, BL), Stipa bungeana Trin. (STBU), Caragana korshinskii Kom. (CAKO), STBU planted with BSCs (STBU+BSCs) and CAKO planted with BSCs (CAKO+BSCs). The runoff, soil loss and soil moisture to a depth of 3 m were measured throughout the rainy season (from June to September) of 2010. The results showed that BSCs significantly reduced runoff by 37.3% and soil loss by 81.0% and increased infiltration by 12.4% in comparison with BL. However, when combined with STBU or CAKO, BSCs only made negligible contributions to erosion control (a runoff reduction of 7.4% and 5.7% and a soil loss reduction of 0.7% and 0.3%). Generally, the soil moisture of the vegetation plots was lower in the upper layer than that of the BL plots, although when accompanied with a higher amount of infiltration, this soil moisture consumption phenomenon was much clearer when combining vegetation with BSCs. Because of the trivial contributions from BSCs to erosion control and the remaining exacerbated consumption of soil water, moderate disturbance by BSCs should be considered in plots with adequate vegetation cover to improve soil moisture levels without a significant erosion increase, which was implied to be necessary and feasible.
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Directory of Open Access Journals (Sweden)
Granieri A
2013-08-01
Full Text Available Antonella Granieri,1 Stella Tamburello,2 Antonino Tamburello,2 Silvia Casale,3 Chiara Cont,1 Fanny Guglielmucci,1 Marco Innamorati21Università degli Studi di Torino, Turin, Italy; 2Università Europea di Roma, Rome, Italy; 3Università di Firenze, Firenze, ItalyAbstract: Asbestos exposure causes significant pleural diseases, including malignant pleural mesothelioma (MPM. Taking into account the impact of MPM on emotional functioning and wellbeing, this study aimed to evaluate the quality of life and personality traits in patients with MPM and their first-degree caregivers through the World Health Organization Quality of Life–BREF (WHOQOL-BREF and the Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF. The sample was composed of 27 MPM patients, 55 first-degree relatives enrolled in Casale Monferrato and Monfalcone (Italy, and 40 healthy controls (HC. Patients and relatives reported poorer physical health than the HC. Patients had a higher overall sense of physical debilitation and poorer health than relatives and the HC, more numerous complaints of memory problems and difficulties in concentrating, and a greater belief that goals cannot be reached or problems solved, while often claiming that they were more indecisive and inefficacious than the HC. First-degree relatives reported lower opinions of others, a greater belief that goals cannot be reached or problems solved, support for the notion that they are indecisive and inefficacious, and were more likely to suffer from fear that significantly inhibited normal activities than were HC. In multinomial regression analyses, partial models indicated that sex, physical comorbidities, and the True Response Inconsistency (TRIN-r, Malaise (MLS, and Behavior-Restricting Fears (BRF dimensions of the MMPI-2-RF had significant effects on group differences. In conclusion, health care providers should assess the ongoing adjustment and emotional wellbeing of people with MPM and their
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Directory of Open Access Journals (Sweden)
Bożena Cwalina-Ambroziak
2012-12-01
Full Text Available Field experiments were carried out in 1999-2001 in the experimental field in Knopin near Dobre Miasto to determine the intensity of fodder galega diseases cultivated in pure sowing and mixed with smooth brome-grass (the Hillstrand and Auld' s modified scale, 1982. The fungi colonising the phyllosphere of fodder galega were analysed in a laboratory (Chruoeciak , 1974. The following symptoms were observed in fodder galega: ascochyta blight (Ascochyta sp., gray mould (Botrytis cinerea and plant wilting (Fusarium oxysporum.. The climatic conditions had an effect on the development of diseases. The greatest intensity of gray mould (Ii = 24.3% and plant wilting (17.9% of plants with the disease symptoms were observed in 2001. Ascochyta blight occurred with the lowest intensity and the highest infection index in 1999 in the cultivation of fodder galega mixed with smooth brome-grass was only 12.1%. The type of cultivation also modified fodder galega disease intensity. Gray mould and plant wilting developed better in pure sowing than in mixed sowing with smooth brome-grass. Throughout the entire experiment period the average infection index was 22.8% and 15.9% of plants with the wilt symptoms. Ascochyta blight found better conditions for development in plants cultivated in a mix with smooth brome-grass (average infection index - 10.0%. The fodder galega phyllosphere provided 4149 fungal isolates represented by 17 species and yeast-like fungi. Yeast-like fungi dominated (75.6% of the total isolates. The following species were less numerous: Botrytis cinerea, Humicola brevis, Acremonium strictum and Cladosporium cladosporioides. From the leaves of fodder galega cultivated in pure sowing, 3.8% more fungi were obtained than from the leaves of plants cultivated with a mix of smooth brome-grass, including more frequently isolated pathogenic fungi representing the genera of Fusarium and the species of Botrytis cinerea.
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Energy Technology Data Exchange (ETDEWEB)
Guerrero-Casado, J.; Carpio, A.J.; Prada, L.M.; Tortosa, F.S.
2015-07-01
Cover crops are an effective means to reduce soil erosion and to provide food and shelter for wildlife. However, in areas of intensive farming, which are characterised by the scarcity of weed communities, wild herbivores may focus their grazing on cover crops, which could make their implementation difficult. In this work, we test whether rabbit grazing can prevent the growth of herbaceous cover crops in olive groves in Southern Spain in addition to assessing the role of rabbit abundance and diversity of weeds in the development of cover crops. This question has been addressed by sowing Bromus rubens between the rows of five olive groves in Cordoba province (Spain). We then monitored the surface covered by B. rubens, along with both diversity of weed communities and rabbit abundance. Two rabbit exclusion areas were also placed in each olive grove in order to assess the impact of rabbits on the development of cover crops. Our results showed that the surface occupied by B. rubens was considerably higher in the rabbit exclusion areas (mean 56.8 ± 5.65 %) than in those areas in which they could feed (mean 35.6 ± 4.32 %). The coverage occupied by cover crops was higher in areas with lower rabbit density, although this relationship was modulated by the weed diversity index, since in areas with the same rabbit abundance the coverage was higher in those with a richer weed community. These findings suggest that high rabbit abundances can prevent the development of herbaceous cover crops in olive groves, particularly in areas in which alternative food resources (measured as weed diversity) are scarce. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Uresk, D.W.; Uresk, V.A.
1980-10-01
Forty-four food items were identified in the fecal pellets of the mule deer (Odocoileus hemionus hemionus) on three areas of the Hanford Site. Microscopic analysis of plant fragments indicated that bitterbrush was the most common species occurring in the diets of deer from the B-C Cribs area. Russian thistle (Salsola kali) and goldenrod (Solidago sp.) were the most abundant plants found in the fecal pellets collected from B Pond and Gable Mountain Pond habitats, respectively. The similarity in diets among the habitats was low, ranging from 10% to 16%. Preference indices of forage plants among sites were not similar (7% to 19%). The B-C Cribs, B Pond and Gable Mountain Pond habitats were characterized for canopy cover and frequency of occurrence of plant species. Twelve species were sampled in the B-C Cribs and B Pond areas; 22 species were identified on the Gable Mountain site. The most commonly occurring plant was cheatgrass (Bromus tectorum) in all three sites. The similarity in frequency and canopy cover of plants was low among sites. Mule deer inhabiting the Hanford site can serve as a pathway for movement of radioactive material from low-level radioactive waste management areas to man. Maximum levels of /sup 137/Cs found in deer pellet groups collected from B Pond and Gable Mountain Pond areas were 100 pCi/g and 128 pCi/g, respectively. Background levels were reported at B-C Cribs area. Maximum /sup 90/Sr values found in deer pellets at B Pond were 107 pCi/g and 184 pCi/g at Gable Mountain Pond.
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Characterization of the Hanford 300 area burial grounds. Task IV. Biological transport
International Nuclear Information System (INIS)
Fitzner, R.E.; Gano, K.A.; Rickard, W.H.; Rogers, L.E.
1979-10-01
The characteristics of radioactive waste burial sites at the 300 area burial grounds on the Department of Energy's Hanford Site, southeastern Washington were studied. The potential vectors of radionuclide transport studied were vegetation and animals. The overall results showed a low potential for uptake and transport of radionuclides from the 300 area sites. However, additional methods to control physical and biological mechanisms may contribute to the effectiveness of waste burial practices. From the results, the Biological Transport task recommended field studies which include reduction of soil erosion and addition of biobarriers to plants and animals. Vegetation plays a major role in reducing soil erosion, and thereby maintaining the backfill over the burial sites. Of the several species found on the 300 area sites, cheatgrass (Bromus tectorum) appears to be the most desirable as a cover. Besides retarding erosion, it has a shallow root system (does not easily penetrate buried material); it has a low affinity for radionuclide uptake; and its tissues are not easily blown away. Small mammals (specifically, mice) appear to have the most potential for radionuclide exposure and uptake. Small mammals were live-trapped within 10 x 10-meter trap grids. Each animal trapped was surgically implanted with a thermoluminescent dosimeter. When the animal was recaptured, the dosimeter was removed and read for exposure. Exposures were reported in milli-Roentgens. The most consistently trapped small mammals were the Great Basin pocket mouse (Perognathus parvus) and the deer mouse (Peromyscus maniculatus). Results from the dosimeter readings showed that some of those animals had higher than background exposures. Biobarriers to animals could be considered as a mechanism to reduce the potential for radionuclide transport
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Characterization of the Hanford 300 area burial grounds. Task IV. Biological transport
Energy Technology Data Exchange (ETDEWEB)
Fitzner, R.E.; Gano, K.A.; Rickard, W.H.; Rogers, L.E.
1979-10-01
The characteristics of radioactive waste burial sites at the 300 area burial grounds on the Department of Energy's Hanford Site, southeastern Washington were studied. The potential vectors of radionuclide transport studied were vegetation and animals. The overall results showed a low potential for uptake and transport of radionuclides from the 300 area sites. However, additional methods to control physical and biological mechanisms may contribute to the effectiveness of waste burial practices. From the results, the Biological Transport task recommended field studies which include reduction of soil erosion and addition of biobarriers to plants and animals. Vegetation plays a major role in reducing soil erosion, and thereby maintaining the backfill over the burial sites. Of the several species found on the 300 area sites, cheatgrass (Bromus tectorum) appears to be the most desirable as a cover. Besides retarding erosion, it has a shallow root system (does not easily penetrate buried material); it has a low affinity for radionuclide uptake; and its tissues are not easily blown away. Small mammals (specifically, mice) appear to have the most potential for radionuclide exposure and uptake. Small mammals were live-trapped within 10 x 10-meter trap grids. Each animal trapped was surgically implanted with a thermoluminescent dosimeter. When the animal was recaptured, the dosimeter was removed and read for exposure. Exposures were reported in milli-Roentgens. The most consistently trapped small mammals were the Great Basin pocket mouse (Perognathus parvus) and the deer mouse (Peromyscus maniculatus). Results from the dosimeter readings showed that some of those animals had higher than background exposures. Biobarriers to animals could be considered as a mechanism to reduce the potential for radionuclide transport.
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A comparison of stable caesium uptake by six grass species of contrasting growth strategy
International Nuclear Information System (INIS)
Willey, N.J.; Martin, M.H.
1997-01-01
Six plants in the family Gramineae were used to investigate the relationship between Cs uptake, nutrient regime and plant growth strategy sensu Grime (1979: Plant Growth Strategies and Vegetation Processes, John Wiley). The roots of 66 day old Elymus repens (L.) Gould., Bromus sterilis L., Agrostis stolonifera L., Anthoxanthum odoratum L., Festuca ovina L. and Nardus stricta L. plants grown in acid-washed sand at high and low nutrient levels were exposed to a 96 h pulse of stable Cs at 0.05 mM, 0.15 mM, 0.3 mM, 1.0 mM and 3.0 mM concentrations. Different nutrient regimes induced large differences in dry wt in E. repens, B. sterilis and A. stolonifera plants but only small differences in N. stricta and F. ovina plants. At high nutrient concentrations, A. stolonifera, A. odoratum, F. ovina and N. stricta shoots showed significantly greater increases in internal Cs concentration with rising external Cs concentrations than did E. repens and B. sterilis shoots. The relationship between increases in shoot and external Cs concentrations was statistically indistinguishable between species in plants grown at the low nutrient concentration. These patterns of Cs uptake ensured that with long-term high K concentrations the more competitive plants (E. repens and B. sterilis) accumulated higher concentrations of Cs from low external concentrations than did non-competitive plants or competitive plants grown at low nutrient levels. It is suggested that the relationship between plant growth strategy sensu Grime (1979) and Cs accumulation patterns may help to explain the different concentrations to which species accumulate radiocaesium from the soil. (author)
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Directory of Open Access Journals (Sweden)
José Guerrero-Casado
2015-09-01
Full Text Available Cover crops are an effective means to reduce soil erosion and to provide food and shelter for wildlife. However, in areas of intensive farming, which are characterised by the scarcity of weed communities, wild herbivores may focus their grazing on cover crops, which could make their implementation difficult. In this work, we test whether rabbit grazing can prevent the growth of herbaceous cover crops in olive groves in Southern Spain in addition to assessing the role of rabbit abundance and diversity of weeds in the development of cover crops. This question has been addressed by sowing Bromus rubens between the rows of five olive groves in Cordoba province (Spain. We then monitored the surface covered by B. rubens, along with both diversity of weed communities and rabbit abundance. Two rabbit exclusion areas were also placed in each olive grove in order to assess the impact of rabbits on the development of cover crops. Our results showed that the surface occupied by B. rubens was considerably higher in the rabbit exclusion areas (mean 56.8 ± 5.65 % than in those areas in which they could feed (mean 35.6 ± 4.32 %. The coverage occupied by cover crops was higher in areas with lower rabbit density, although this relationship was modulated by the weed diversity index, since in areas with the same rabbit abundance the coverage was higher in those with a richer weed community. These findings suggest that high rabbit abundances can prevent the development of herbaceous cover crops in olive groves, particularly in areas in which alternative food resources (measured as weed diversity are scarce.
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Diversity of bacteria nesting the plant cover of north Sinai deserts, Egypt
Directory of Open Access Journals (Sweden)
Amira L. Hanna
2013-01-01
Full Text Available North Sinai deserts were surveyed for the predominant plant cover and for the culturable bacteria nesting their roots and shoots. Among 43 plant species reported, 13 are perennial (e.g. Fagonia spp., Pancratium spp. and 30 annuals (e.g. Bromus spp., Erodium spp.. Eleven species possessed rhizo-sheath, e.g. Cyperus capitatus, Panicum turgidum and Trisetaria koelerioides. Microbiological analyses demonstrated: the great diversity and richness of associated culturable bacteria, in particular nitrogen-fixing bacteria (diazotrophs; the majority of bacterial residents were of true and/or putative diazotrophic nature; the bacterial populations followed an increasing density gradient towards the root surfaces; sizeable populations were able to reside inside the root (endorhizosphere and shoot (endophyllosphere tissues. Three hundred bacterial isolates were secured from studied spheres. The majority of nitrogen-fixing bacilli isolates belonged to Bacillus megaterium, Bacillus pumilus, Bacillus polymexa, Bacillus macerans, Bacillus circulans and Bacillus licheniformis. The family Enterobacteriaceae represented by Enterobacter agglomerans, Enterobacter sackazakii, Enterobacter cloacae, Serratia adorifera, Serratia liquefaciens and Klebsiella oxytoca. The non-Enterobacteriaceae population was rich in Pantoae spp., Agrobacterium rdiobacter, Pseudomonas vesicularis, Pseudomonas putida, Stenotrophomonas maltophilia, Ochrobactrum anthropi, Sphingomonas paucimobilis and Chrysemonas luteola. Gluconacetobacter diazotrophicus were reported inside root and shoot tissues of a number of tested plants. The dense bacterial populations reported speak well to the very possible significant role played by the endophytic bacterial populations in the survival, in respect of nutrition and health, of existing plants. Such groups of diazotrophs are good candidates, as bio-preparates, to support the growth of future field crops grown in deserts of north Sinai and irrigated by the
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The use of less common grass varieties as a factor of increasing forage lands productivity
Directory of Open Access Journals (Sweden)
В. Д. Бугайов
2017-03-01
Full Text Available Purpose. To assess introduced samples of drought-resistant species of perennial grasses, select a promising parent material and create on its base high-yielding varie ies with economic characters. Methods. Field experiment, laboratory testing. Results. The results of studies on introduction and breeding were given aimed to improve drought tolerance of non-traditional perennial grasses under the conditions of the Right-Bank Forest-Steppe zone of Ukraine. Based on the selected parent material, varieties were created by the use of hybridization and ecotype breeding methods and then entered into the State Register of plant varieties suitable for dissemination in Ukraine, among them: intermediate wheatgrass (Elytrigia intermedia (Host Nevski – ‘Hors’, crested wheatgrass (Agropyron cristatum (L. Gaertn. – ‘Petrivskyi’; meadow brome (Bromus riparia Rehm. – ‘Boian’; slender wheatgrass (Roegneria trachycaulon (Link Nevski – ‘Coumb’. As compared with conventional, relatively drought-tolerant species of smooth brome (Bromopsis inermis (Leyss. Holub – ‘Mars’, increment of dry matter content of these species in the extreme drought conditions of 2011 was increased by 1,52–3,73 t/ha. Under more sufficient moistening conditions of 2012, slender wheatgrass ‘Columb’ was at the level of the сheck variety in terms of this indicator. Other varieties exceeded it by 1.44–3.22 t/ha. The data was given including seed productivity and sowing quality indicators, after-ripening duration and economic fitness of seeds. Conclusions. The use of the recommended varieties of drought-resistant species of perennial grasses as part of grass mixtures will increase significantly the productivity of grasslands and pastures in the current context of climate change.
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Root plasticity buffers competition among plants: theory meets experimental data.
Schiffers, Katja; Tielbörger, Katja; Tietjen, Britta; Jeltsch, Florian
2011-03-01
Morphological plasticity is a striking characteristic of plants in natural communities. In the context of foraging behavior particularly, root plasticity has been documented for numerous species. Root plasticity is known to mitigate competitive interactions by reducing the overlap of the individuals' rhizospheres. But despite its obvious effect on resource acquisition, plasticity has been generally neglected in previous empirical and theoretical studies estimating interaction intensity among plants. In this study, we developed a semi-mechanistic model that addresses this shortcoming by introducing the idea of compensatory growth into the classical-zone-of influence (ZOI) and field-of-neighborhood (FON) approaches. The model parameters describing the belowground plastic sphere of influence (PSI) were parameterized using data from an accompanying field experiment. Measurements of the uptake of a stable nutrient analogue at distinct distances to the neighboring plants showed that the study species responded plastically to belowground competition by avoiding overlap of individuals' rhizospheres. An unexpected finding was that the sphere of influence of the study species Bromus hordeaceus could be best described by a unimodal function of distance to the plant's center and not with a continuously decreasing function as commonly assumed. We employed the parameterized model to investigate the interplay between plasticity and two other important factors determining the intensity of competitive interactions: overall plant density and the distribution of individuals in space. The simulation results confirm that the reduction of competition intensity due to morphological plasticity strongly depends on the spatial structure of the competitive environment. We advocate the use of semi-mechanistic simulations that explicitly consider morphological plasticity to improve our mechanistic understanding of plant interactions.
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Crested wheatgrass-cheatgrass seedling competition in a mixed-density design
Francis, Mark G.; Pyke, David A.
1996-01-01
Plant competition experiments have historically used designs that are difficult to interpret due to confounding problems. Recently, designs based on a 'response function' approach have been proposed and tested in various plant mixture settings. For this study, 3 species were used that are important in current revegetation practices in the Intermountain West. 'Nordan' (Agropyron desertorum [Fish. ex Link] Shult.) and 'Hycrest' (A. cristatum [L.] Gaertn. x desertorum) crested wheatgrass are commonly-used revegetation species on rangelands susceptible to cheatgrass (Bromus tectorum L.) invasion, although little quantitative data exist that compare their competitive abilities. We evaluated the competitive ability of Hycrest and Nordan seedlings in 2-species mixtures with cheatgrass in a greenhouse study. Linear and nonlinear models were developed for a range of densities (130- 520 seeds m-2) for each species to predict median above-ground biomass and tiller numbers and to further test the usefulness of this design for evaluating species to rehabilitate rangelands. In both experiments, increasing Hycrest and Nordan densities reduced their own biomass and tiller production while increasing Hycrest densities reduced cheatgrass biomass and tiller production. Nordan did not affect cheatgrass biomass and tiller production. However, increasing cheatgrass densities reduced Hycrest and Nordan biomass and tiller production, and its own biomass and tiller production. The competition index i.e. substitution rate, indicated that Hycrest seedlings were better competitors with cheatgrass than Nordan, although in all mixtures, cheatgrass plants were the superior competitors. Further field research using this design, where environmental inputs are less optimal and diverse, is needed to validate these results and to further evaluate the use of this approach in examining effects of intra- and interspecific competition.
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International Nuclear Information System (INIS)
Uresk, D.W.; Uresk, V.A.
1980-10-01
Forty-four food items were identified in the fecal pellets of the mule deer (Odocoileus hemionus hemionus) on three areas of the Hanford Site. Microscopic analysis of plant fragments indicated that bitterbrush was the most common species occurring in the diets of deer from the B-C Cribs area. Russian thistle (Salsola kali) and goldenrod (Solidago sp.) were the most abundant plants found in the fecal pellets collected from B Pond and Gable Mountain Pond habitats, respectively. The similarity in diets among the habitats was low, ranging from 10% to 16%. Preference indices of forage plants among sites were not similar (7% to 19%). The B-C Cribs, B Pond and Gable Mountain Pond habitats were characterized for canopy cover and frequency of occurrence of plant species. Twelve species were sampled in the B-C Cribs and B Pond areas; 22 species were identified on the Gable Mountain site. The most commonly occurring plant was cheatgrass (Bromus tectorum) in all three sites. The similarity in frequency and canopy cover of plants was low among sites. Mule deer inhabiting the Hanford site can serve as a pathway for movement of radioactive material from low-level radioactive waste management areas to man. Maximum levels of 137 Cs found in deer pellet groups collected from B Pond and Gable Mountain Pond areas were 100 pCi/g and 128 pCi/g, respectively. Background levels were reported at B-C Cribs area. Maximum 90 Sr values found in deer pellets at B Pond were 107 pCi/g and 184 pCi/g at Gable Mountain Pond
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DeCrappeo, Nicole; DeLorenze, Elizabeth J.; Giguere, Andrew T; Pyke, David A.; Bottomley, Peter J.
2017-01-01
AimThere is interest in determining how cheatgrass (Bromus tectorum L.) modifies N cycling in sagebrush (Artemisia tridentata Nutt.) soils of the western USA.MethodsTo gain insight into the roles of fungi and bacteria in N cycling of cheatgrass-invaded and uninvaded sagebrush soils, the fungal protein synthesis inhibitor, cycloheximide (CHX), and the bacteriocidal compound, bronopol (BRO) were combined with a 15NH4+ isotope pool dilution approach.ResultsCHX reduced gross N mineralization to the same rate in both sagebrush and cheatgrass soils indicating a role for fungi in N mineralization in both soil types. In cheatgrass soils BRO completely inhibited gross N mineralization, whereas, in sagebrush soils a BRO-resistant gross N mineralization rate was detected that was slower than CHX sensitive gross N mineralization, suggesting that the microbial drivers of gross N mineralization were different in sagebrush and cheatgrass soils. Net N mineralization was stimulated to a higher rate in sagebrush than in cheatgrass soils by CHX, implying that a CHX inhibited N sink was larger in the former than the latter soils. Initial gross NH4+ consumption rates were reduced significantly by both CHX and BRO in both soil types, yet, consumption rates recovered significantly between 24 and 48 h in CHX-treated sagebrush soils. The recovery of NH4+ consumption in sagebrush soils corresponded with an increase in the rate of net nitrification.ConclusionsThese results suggest that cheatgrass invasion of sagebrush soils of the northern Great Basin reduces the capacity of the fungal N consumption sink, enhances the capacity of a CHX resistant N sink and alters the contributions of bacteria and fungi to gross N mineralization.
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The Seed Semipermeable Layer and Its Relation to Seed Quality Assessment in Four Grass Species
Directory of Open Access Journals (Sweden)
Yan Y. Lv
2017-07-01
Full Text Available The existence of a semipermeable layer in grass seeds has been extensively reported, yet knowledge of its influence on tests for seed viability and vigor that depend upon measurement of electrical conductivity (EC is limited. This study determined the presence and location of the semipermeable layer, and its relation to seed viability and vigor assessment, in seeds of four important grass species-Elymus nutans Griseb., Lolium perenne L., Leymus chinensis (Trin. Tzvel., and Avena sativa L. Intact seeds of E. nutans, Lolium perenne, and Leymus chinensis exhibited little staining with triphenyl tetrazolium chloride (TTC, and there were no differences in EC between seeds with different germination percentage (GP (P > 0.05. After piercing the seed coat, however, all three species displayed positive staining with TTC, along with a significant negative correlation between EC and GP (E. nutans: R2 = 0.7708; Lolium perenne: R2= 0.8414; Leymus chinensis: R2 = 0.859; P < 0.01. In contrast, both intact and pierced seeds of A. sativa possessed a permeable seed coat that showed positive staining with TTC and EC values that were significantly negatively correlated with GP [R2 = 0.9071 (intact and 0.9597 (pierced; P < 0.01]. In commercial seed lots of A. sativa, a field emergence test indicated that EC showed a significant negative correlation with field emergence at two sowing dates (R2= 0.6069, P < 0.01 and 0.5316, P < 0.05. Analysis of seed coat permeability revealed the presence of a semipermeable layer located in the seed coat adjacent to the endosperm in E. nutans, Lolium perenne, and Leymus chinensis; however, no semipermeable layer was observed in A. sativa. This is the first report of the absence of a semipermeable layer in a grass species. The existence of a semipermeable layer is one of the most important factors affecting seed viability and vigor testing (based on EC measurement in E. nutans, Lolium perenne, and Leymus chinensis. Increasing the
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Energy Technology Data Exchange (ETDEWEB)
Waechtler, Thomas
2010-05-25
Copper-based multi-level metallization systems in today's ultralarge-scale integrated electronic circuits require the fabrication of diffusion barriers and conductive seed layers for the electrochemical metal deposition. Such films of only several nanometers in thickness have to be deposited void-free and conformal in patterned dielectrics. The envisaged further reduction of the geometric dimensions of the interconnect system calls for coating techniques that circumvent the drawbacks of the well-established physical vapor deposition. The atomic layer deposition method (ALD) allows depositing films on the nanometer scale conformally both on three-dimensional objects as well as on large-area substrates. The present work therefore is concerned with the development of an ALD process to grow copper oxide films based on the metal-organic precursor bis(trin- butylphosphane)copper(I)acetylacetonate [({sup n}Bu{sub 3}P){sub 2}Cu(acac)]. This liquid, non-fluorinated {beta}-diketonate is brought to react with a mixture of water vapor and oxygen at temperatures from 100 to 160 C. Typical ALD-like growth behavior arises between 100 and 130 C, depending on the respective substrate used. On tantalum nitride and silicon dioxide substrates, smooth films and selfsaturating film growth, typical for ALD, are obtained. On ruthenium substrates, positive deposition results are obtained as well. However, a considerable intermixing of the ALD copper oxide with the underlying films takes place. Tantalum substrates lead to a fast self-decomposition of the copper precursor. As a consequence, isolated nuclei or larger particles are always obtained together with continuous films. The copper oxide films grown by ALD can be reduced to copper by vapor-phase processes. If formic acid is used as the reducing agent, these processes can already be carried out at similar temperatures as the ALD, so that agglomeration of the films is largely avoided. Also for an integration with subsequent
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Energy Technology Data Exchange (ETDEWEB)
Waechtler, Thomas
2010-05-25
Copper-based multi-level metallization systems in today's ultralarge-scale integrated electronic circuits require the fabrication of diffusion barriers and conductive seed layers for the electrochemical metal deposition. Such films of only several nanometers in thickness have to be deposited void-free and conformal in patterned dielectrics. The envisaged further reduction of the geometric dimensions of the interconnect system calls for coating techniques that circumvent the drawbacks of the well-established physical vapor deposition. The atomic layer deposition method (ALD) allows depositing films on the nanometer scale conformally both on three-dimensional objects as well as on large-area substrates. The present work therefore is concerned with the development of an ALD process to grow copper oxide films based on the metal-organic precursor bis(trin- butylphosphane)copper(I)acetylacetonate [({sup n}Bu{sub 3}P){sub 2}Cu(acac)]. This liquid, non-fluorinated {beta}-diketonate is brought to react with a mixture of water vapor and oxygen at temperatures from 100 to 160 C. Typical ALD-like growth behavior arises between 100 and 130 C, depending on the respective substrate used. On tantalum nitride and silicon dioxide substrates, smooth films and selfsaturating film growth, typical for ALD, are obtained. On ruthenium substrates, positive deposition results are obtained as well. However, a considerable intermixing of the ALD copper oxide with the underlying films takes place. Tantalum substrates lead to a fast self-decomposition of the copper precursor. As a consequence, isolated nuclei or larger particles are always obtained together with continuous films. The copper oxide films grown by ALD can be reduced to copper by vapor-phase processes. If formic acid is used as the reducing agent, these processes can already be carried out at similar temperatures as the ALD, so that agglomeration of the films is largely avoided. Also for an integration with subsequent
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Directory of Open Access Journals (Sweden)
Marta Bruno Loureiro
2013-12-01
Full Text Available Jatropha curcas L., conhecida popularmente como pinhão-manso, é uma espécie encontrada em quase todas as regiões intertropicais do planeta. Possui sementes oleaginosas de importância medicinal e econômica, sendo apontada atualmente como promissora fonte de matéria-prima para a produção de biocombustíveis. Os objetivos deste trabalho consistiram em identificar as diferentes fases do processo de germinação, descrever e ilustrar a morfologia de sementes e plântulas de Jatropha curcas L. e os aspectos anatômicos das sementes, relacionando as mudanças que ocorrem nos tecidos durante as fases de embebição. Para a análise morfológica das sementes e plântulas, observaram-se os detalhes externos e internos. Para o estudo das fases de germinação, foi realizado um ensaio para avaliar o comportamento das sementes durante a embebição; para a análise anatômica, foram preparadas lâminas permanentes com cortes das sementes após 0, 4, 24 e 72 h de embebição. As sementes de Jatropha curcas L. são endospermáticas, elípticas e anátropas com tegumento glabro, possuindo poros e fissuras em sua superfície. Os cotilédones são foliáceos, com formato cordiforme e nervuras trinérvias. A germinação é do tipo fanerocotiledonar, epígea. Anatomicamente, as sementes são albuminosas, sendo o tegumento constituído de células parenquimáticas, vacuoladas e poligonais com feixes vasculares e células esclereficadas. O endosperma é composto por células poliédricas ricas em substâncias de reserva, principalmente lipídios. Durante as fases de germinação, observaram-se alterações no acúmulo de grânulos de amido presentes no endosperma, bem como mudanças na organização dos seus feixes vasculares.
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Energy Technology Data Exchange (ETDEWEB)
Menser, H.A.; Winant, W.M.; Bennett, O.L.; Lundberg, P.E.
1979-01-01
Spray irrigation was used to test the survival and efficiency of forage grasses as a concentrating mechanism for the inorganic waste elements in leachate from a municipal solid waste sanitary landfill. Lime (0.67 metric tonnes ha), rock phosphate, and superphosphate (each at 11.2 metric tonnes ha) were applied in a randomised complete block design to reed canarygrass Phalaris arundinacea L., tall fescue Festuca arundinacea Schreb., cv. Ky31, orchardgrass Dactylis glomerata L., bromegrass Bromus inermis Leyss., and bermudagrass Cynodon dactylon (L.) Pers. cvs. Midland and Tufcote. Leachate was applied by overhead rotary sprinklers in weekly 8-h applications from 22 October 1974 to 28 April 1975. The total application averages about 155 cm. Sprayed leachate contained about 500 ppM of Ca, 150 to 200 ppM of Na, Fe, and Cl, 50 to 100 ppM of Mn, K, Mg, and N, 2 to 5 ppM of Al, Sr, Zn, and P, and less than 0.5 ppM of Ni, Co, Cr, Cu, Pb, and Cd. Chemical oxygen demand (COD) decreased from approximately 7500 mg liter in water emerging from landfill drains to 5000 mg litre in sprayed leachate. Electroconductivity ranged from 3000 to 4000 ..mu..mhos cm and pH from 5.3 to about 5.5. Leachate irrigation appreciably increased Na, Fe, Mn, Cl, and S levels in all forages except orchardgrass. Lime significantly prevented Mn accumulation and benefited forage grass persistence. Reed canarygrass generally contained the highest levels of most elements and along with Tufcote bermudagrass was more leachate-tolerant than other grasses. Seasonal factors affected the uptake of several elements, e.g. Na, Fe, Mn, Zn, K and Co were significantly lower in regrowth cuttings as compared with first cuttings of Midland bermudagrass and reed canarygrass.
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Zhou, Xiaobo; Helmers, Matthew J; Asbjornsen, Heidi; Kolka, Randy; Tomer, Mark D
2010-01-01
Many croplands planted to perennial grasses under the Conservation Reserve Program are being returned to crop production, and with potential consequences for water quality. The objective of this study was to quantify the impact of grassland-to-cropland conversion on nitrate-nitrogen (NO3-N) concentrations in soil and shallow groundwater and to assess the potential for perennial filter strips (PFS) to mitigate increases in NO3-N levels. The study, conducted at the Neal Smith National Wildlife Refuge (NSNWR) in central Iowa, consisted of a balanced incomplete block design with 12 watersheds and four watershed-scale treatments having different proportions and topographic positions of PFS planted in native prairie grasses: 100% rowcrop, 10% PFS (toeslope position), 10% PFS (distributed on toe and as contour strips), and 20 PFS (distributed on toe and as contour strips). All treatments were established in fall 2006 on watersheds that were under bromegrass (Bromus L.) cover for at least 10 yr. Nonperennial areas were maintained under a no-till 2-yr corn (Zea mays L.)--soybean [Glycine max. (L.) Merr.] rotation since spring 2007. Suction lysimeter and shallow groundwater wells located at upslope and toeslope positions were sampled monthly during the growing season to determine NO3-N concentration from 2005 to 2008. The results indicated significant increases in NO3-N concentration in soil and groundwater following grassland-to-cropland conversion. Nitrate-nitrogen levels in the vadose zone and groundwater under PFS were lower compared with 100% cropland, with the most significant differences occurring at the toeslope position. During the years following conversion, PFS mitigated increases in subsurface nitrate, but long-term monitoring is needed to observe and understand the full response to land-use conversion.
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Mixed artificial grasslands with more roots improved mine soil infiltration capacity
Wu, Gao-Lin; Yang, Zheng; Cui, Zeng; Liu, Yu; Fang, Nu-Fang; Shi, Zhi-Hua
2016-04-01
Soil water is one of the critical limiting factors in achieving sustainable revegetation. Soil infiltration capacity plays a vital role in determining the inputs from precipitation and enhancing water storage, which are important for the maintenance and survival of vegetation patches in arid and semi-arid areas. Our study investigated the effects of different artificial grasslands on soil physical properties and soil infiltration capacity. The artificial grasslands were Medicago sativa, Astragalus adsurgens, Agropyron mongolicum, Lespedeza davurica, Bromus inermis, Hedysarum scoparium, A. mongolicum + Artemisia desertorum, A. adsurgens + A. desertorum and M. sativa + B. inermis. The soil infiltration capacity index (SICI), which was based on the average infiltration rate of stage I (AIRSI) and the average infiltration rate of stage III (AIRS III), was higher (indicating that the infiltration capacity was greater) under the artificial grasslands than that of the bare soil. The SICI of the A. adsurgens + A. desertorum grassland had the highest value (1.48) and bare soil (-0.59) had the lowest value. It was evident that artificial grassland could improve soil infiltration capacity. We also used principal component analysis (PCA) to determine that the main factors that affected SICI were the soil water content at a depth of 20 cm (SWC20), the below-ground root biomasses at depths of 10 and 30 cm (BGB10, BGB30), the capillary porosity at a depth of 10 cm (CP10) and the non-capillary porosity at a depth of 20 cm (NCP20). Our study suggests that the use of Legume-poaceae mixtures and Legume-shrub mixtures to create grasslands provided an effective ecological restoration approach to improve soil infiltration properties due to their greater root biomasses. Furthermore, soil water content, below-ground root biomass, soil capillary porosity and soil non-capillary porosity were the main factors that affect the soil infiltration capacity.
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Chambers, Jeanne C.; Miller, Richard F.; Board, David I.; Pyke, David A.; Roundy, Bruce A.; Grace, James B.; Schupp, Eugene W.; Tausch, Robin J.
2014-01-01
In sagebrush ecosystems invasion of annual exotics and expansion of piñon (Pinus monophylla Torr. and Frem.) and juniper (Juniperus occidentalis Hook., J. osteosperma [Torr.] Little) are altering fire regimes and resulting in large-scale ecosystem transformations. Management treatments aim to increase resilience to disturbance and enhance resistance to invasive species by reducing woody fuels and increasing native perennial herbaceous species. We used Sagebrush Steppe Treatment Evaluation Project data to test predictions on effects of fire vs. mechanical treatments on resilience and resistance for three site types exhibiting cheatgrass (Bromus tectorum L.) invasion and/or piñon and juniper expansion: 1) warm and dry Wyoming big sagebrush (WY shrub); 2) warm and moist Wyoming big sagebrush (WY PJ); and 3) cool and moist mountain big sagebrush (Mtn PJ). Warm and dry (mesic/aridic) WY shrub sites had lower resilience to fire (less shrub recruitment and native perennial herbaceous response) than cooler and moister (frigid/xeric) WY PJ and Mtn PJ sites. Warm (mesic) WY Shrub and WY PJ sites had lower resistance to annual exotics than cool (frigid to cool frigid) Mtn PJ sites. In WY shrub, fire and sagebrush mowing had similar effects on shrub cover and, thus, on perennial native herbaceous and exotic cover. In WY PJ and Mtn PJ, effects were greater for fire than cut-and-leave treatments and with high tree cover in general because most woody vegetation was removed increasing resources for other functional groups. In WY shrub, about 20% pretreatment perennial native herb cover was necessary to prevent increases in exotics after treatment. Cooler and moister WY PJ and especially Mtn PJ were more resistant to annual exotics, but perennial native herb cover was still required for site recovery. We use our results to develop state and transition models that illustrate how resilience and resistance influence vegetation dynamics and management options.
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Carbon balances during land conversion in early bioenergy systems
Zenone, T.; Chen, J.; Gelfand, I.; Robertson, G. P.; Hamilton, S. K.
2012-12-01
In this study, we established a field experiment and deployed seven eddy-covariance towers to quantify the roles of land use change and the subsequent carbon (C) balances of three different bioenergy systems (corn, switchgrass, and mixed prairie species) that were developed from two historical land use types: monocultural grasslands dominated by smooth brome (Bromus inermis Leyss) and lands in the Conservation Reserve Program (CRP). Three CRP fields and three cropland fields were converted to soybean in 2009 (conversion year) before establishing the cellulosic biofuel cropping systems in 2010 (establishment year). A CRP perennial grassland site was kept undisturbed as a reference. Conversion of CRP to soybean induced net C emissions during the conversion year (134 -262 g C m-2 yr-1), while in the same year the net C balance at the CRP grassland reference was -35 g C m-2 yr-1 (i.e., net C sequestration). The establishment of switchgrass and mixed prairie induced a cumulative C balance of -113 g C m-2 (switchgrass from CRP), 250 g C m-2 (switchgrass from cropland), 706 g C m-2 (mixed prairie from CRP), and 59 g C m-2 (mixed prairie from cropland) over the three-year study period. The cumulative three-year C balance of corn converted from CRP and from cropland was -151 g C m-2 and -183 g C m-2, respectively. Eddy flux measurements during cellulosic biofuel crop establishment reveal annual changes in C balance that cannot be detected using conventional mass balance approaches. When end-use of harvested biomass was considered, the C balances for all studied systems, except the reference site, exhibited large C emissions ranging from 150 to 990 g C m-2 over the three-year conversion phase.
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Managed grassland alters soil N dynamics and N2O emissions in temperate steppe.
Xu, Lijun; Xu, Xingliang; Tang, Xuejuan; Xin, Xiaoping; Ye, Liming; Yang, Guixia; Tang, Huajun; Lv, Shijie; Xu, Dawei; Zhang, Zhao
2018-04-01
Reclamation of degraded grasslands as managed grasslands has been increasingly accelerated in recent years in China. Land use change affects soil nitrogen (N) dynamics and nitrous oxide (N 2 O) emissions. However, it remains unclear how large-scale grassland reclamation will impact the grassland ecosystem as a whole. Here, we investigated the effects of the conversion from native to managed grasslands on soil N dynamics and N2O emissions by field experiments in Hulunber in northern China. Soil (0-10cm), nitrate (NO 3 - ), ammonium (NH 4 + ), and microbial N were measured in plots in a temperate steppe (Leymus chinensis grassland) and two managed grasslands (Medicago sativa and Bromus inermis grasslands) in 2011 and 2012. The results showed conversion of L. chinensis grassland to M. sativa or B. inermis grasslands decreased concentrations of NO 3 - -N, but did not change NH 4 + -N. Soil microbial N was slightly decreased by the conversion of L. chinensis grassland to M. sativa, but increased by the conversion to B. inermis. The conversion of L. chinensis grassland to M. sativa (i.e., a legume grass) increased N 2 O emissions by 26.2%, while the conversion to the B. inermis (i.e., a non-legume grass) reduced N 2 O emissions by 33.1%. The conversion from native to managed grasslands caused large created variations in soil NO 3 - -N and NH 4 + -N concentrations. Net N mineralization rates did not change significantly in growing season or vegetation type, but to net nitrification rate. These results provide evidence on how reclamation may impact the grassland ecosystem in terms of N dynamics and N 2 O emissions. Copyright © 2017. Published by Elsevier B.V.
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Boyte, Stephen P.; Wylie, Bruce K.; Major, Donald J.
2016-01-01
Cheatgrass (Bromus tectorum L.) is a highly invasive species in the Northern Great Basin that helps decrease fire return intervals. Fire fragments the shrub steppe and reduces its capacity to provide forage for livestock and wildlife and habitat critical to sagebrush obligates. Of particular interest is the greater sage grouse (Centrocercus urophasianus), an obligate whose populations have declined so severely due, in part, to increases in cheatgrass and fires that it was considered for inclusion as an endangered species. Remote sensing technologies and satellite archives help scientists monitor terrestrial vegetation globally, including cheatgrass in the Northern Great Basin. Along with geospatial analysis and advanced spatial modeling, these data and technologies can identify areas susceptible to increased cheatgrass cover and compare these with greater sage grouse priority areas for conservation (PAC). Future climate models forecast a warmer and wetter climate for the Northern Great Basin, which likely will force changing cheatgrass dynamics. Therefore, we examine potential climate-caused changes to cheatgrass. Our results indicate that future cheatgrass percent cover will remain stable over more than 80% of the study area when compared with recent estimates, and higher overall cheatgrass cover will occur with slightly more spatial variability. The land area projected to increase or decrease in cheatgrass cover equals 18% and 1%, respectively, making an increase in fire disturbances in greater sage grouse habitat likely. Relative susceptibility measures, created by integrating cheatgrass percent cover and temporal standard deviation datasets, show that potential increases in future cheatgrass cover match future projections. This discovery indicates that some greater sage grouse PACs for conservation could be at heightened risk of fire disturbance. Multiple factors will affect future cheatgrass cover including changes in precipitation timing and totals and
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Grant, T.A.; Flanders-Wanner, B.; Shaffer, T.L.; Murphy, R.K.; Knutsen, G.A.
2009-01-01
In the northern Great Plains, native prairies managed by the U.S. Fish and Wildlife Service (Service) can be pivotal in conservation of North America's biological diversity. From 2002 to 2006, we surveyed 7,338 belt transects to assess the general composition of mixed-grass and tallgrass prairie vegetation across five "complexes" (i.e., administrative groupings) of national wildlife refuges managed by the Service in North Dakota and South Dakota. Native grasses and forbs were common (mean frequency of occurrence 47%-54%) on two complexes but uncommon (4%-13%) on two others. Conversely, an introduced species of grass, smooth brome (Bromus inermis), accounted for 45% to 49% of vegetation on two complexes and another species, Kentucky bluegrass (Poa pratensis) accounted for 27% to 36% of the vegetation on three of the complexes. Our data confirm prior suspicions of widespread invasion by introduced species of plants on Service-owned tracts of native prairie, changes that likely stem in part from a common management history of little or no disturbance (e.g., defoliation by grazing or fire). However, variability in the degree and type of invasion among prairie tracts suggests that knowledge of underlying causes (e.g., edaphic or climatic factors, management histories) could help managers more effectively restore prairies. We describe an adaptive management approach to acquire such knowledge while progressing with restoration. More specifically, we propose to use data from inventories of plant communities on Service-owned prairies to design and implement, as experiments, optimal restoration strategies. We will then monitor these experiments and use the results to refine future strategies. This comprehensive, process-oriented approach should yield reliable and robust recommendations for restoration and maintenance of native prairies in the northern Great Plains. 2009 by the Board of Regents of the University of Wisconsin System.
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Lockyer, Zachary B.; Coates, Peter S.; Casazza, Michael L.; Espinosa, Shawn; Delehanty, David J.
2015-01-01
Identifying links between micro-habitat selection and wildlife reproduction is imperative to population persistence and recovery. This information is particularly important for landscape species such as greater sage-grouse (Centrocercus urophasianus; sage-grouse). Although this species has been widely studied, because environmental factors can affect sage-grouse populations, local and regional studies are crucial for developing viable conservation strategies. We studied the habitat-use patterns of 71 radio-marked sage-grouse inhabiting an area affected by wildfire in the Virginia Mountains of northwestern Nevada during 2009–2011 to determine the effect of micro-habitat attributes on reproductive success. We measured standard vegetation parameters at nest and random sites using a multi-scale approach (range = 0.01–15,527 ha). We used an information-theoretic modeling approach to identify environmental factors influencing nest-site selection and survival, and determine whether nest survival was a function of resource selection. Sage-grouse selected micro-sites with greater shrub canopy cover and less cheatgrass (Bromus tectorum) cover than random sites. Total shrub canopy, including sagebrush (Artemisia spp.) and other shrub species, at small spatial scales (0.8 ha and 3.1 ha) was the single contributing selection factor to higher nest survival. These results indicate that reducing the risk of wildfire to maintain important sagebrush habitats could be emphasized in sage-grouse conservation strategies in Nevada. Managers may seek to mitigate the influx of annual grass invasion by preserving large intact sagebrush-dominated stands with a mixture of other shrub species. For this area of Nevada, the results suggest that ≥40% total shrub canopy cover in sage-grouse nesting areas could yield improved reproductive success.
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Williams, C. J.; Pierson, F. B.; Robichaud, P. R.; Spaeth, K. E.; Hardegree, S. P.; Clark, P. E.; Moffet, C. A.; Al-Hamdan, O. Z.; Boll, J.
2010-12-01
Landscape-scale plant community transitions and altered fire regimes across Great Basin, USA, rangelands have increased the likelihood of post-fire flooding and erosion events. These hazards are particularly concerning for western urban centers along the rangeland urban-wildland interface where natural resources, property, and human life are at risk. Extensive conversion of 4-7 million hectares of Great Basin shrub-steppe to cheatgrass-dominated (Bromus tectorum) grasslands has increased the frequency and size of wildland fires within these ecosystems. Fire frequencies have increased by more than an order of magnitude and occur on 3-10 year intervals across much of the cheatgrass-dominated landscape. Extensive tree (Pinus spp. and Juniperus spp.) encroachment into wooded shrub-steppe has increased heavy fuel loads. Ladder fuels in these ecosystems promote rapidly spreading, high-intensity and severe ground-surface-crown fires. These altered fuel structures across much of the historical Great Basin shrub-steppe have initiated an upsurge in large rangeland wildfires and have increased the spatial and temporal vulnerability of these landscapes to amplified runoff and erosion. Resource and infrastructure damages, and loss of life have been reported due to flooding following recent large-scale burning of western rangelands and dry forests. We present a decade of post-fire rangeland hydrologic research that provides a foundation for conceptual modeling of the hydrologic impacts associated with an increased role of rangeland wildfires. We highlight advancements in predictive tools to address this large-scale phenomenon and discuss vital research voids requiring attention. Our geographic emphasis is the Great Basin Region, however, these concepts likely extend elsewhere given the increased role of fire in many geographic regions and across rangeland-to-forest ecotones in the western United States.
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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. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.
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Ceradnini, Joseph P.; Chalfoun, Anna
2017-01-01
Modification of habitat structure due to invasive plants can alter the risk landscape for wildlife by, for example, changing the quality or availability of refuge habitat. Whether perceived risk corresponds with actual fitness outcomes, however, remains an important open question. We simultaneously measured how habitat changes due to a common invasive grass (cheatgrass, Bromus tectorum) affected the perceived risk, habitat selection, and apparent survival of a small mammal, enabling us to assess how well perceived risk influenced important behaviors and reflected actual risk. We measured perceived risk by nocturnal rodents using a giving-up density foraging experiment with paired shrub (safe) and open (risky) foraging trays in cheatgrass and native habitats. We also evaluated microhabitat selection across a cheatgrass gradient as an additional assay of perceived risk and behavioral responses for deer mice (Peromyscus maniculatus) at two spatial scales of habitat availability. Finally, we used mark-recapture analysis to quantify deer mouse apparent survival across a cheatgrass gradient while accounting for detection probability and other habitat features. In the foraging experiment, shrubs were more important as protective cover in cheatgrass-dominated habitats, suggesting that cheatgrass increased perceived predation risk. Additionally, deer mice avoided cheatgrass and selected shrubs, and marginally avoided native grass, at two spatial scales. Deer mouse apparent survival varied with a cheatgrass–shrub interaction, corresponding with our foraging experiment results, and providing a rare example of a native plant mediating the effects of an invasive plant on wildlife. By synthesizing the results of three individual lines of evidence (foraging behavior, habitat selection, and apparent survival), we provide a rare example of linkage between behavioral responses of animals indicative of perceived predation risk and actual fitness outcomes. Moreover, our results
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A common-garden study of resource-island effects on a native and an exotic, annual grass after fire
Hoover, Amber N.; Germino, Matthew J.
2012-01-01
Plant-soil variation related to perennial-plant resource islands (coppices) interspersed with relatively bare interspaces is a major source of heterogeneity in desert rangelands. Our objective was to determine how native and exotic grasses vary on coppice mounds and interspaces (microsites) in unburned and burned sites and underlying factors that contribute to the variation in sagebrush-steppe rangelands of the Idaho National Lab, where interspaces typically have abiotic crusts. We asked how the exotic cheatgrass (Bromus tectorum L.) and native bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Löve) were distributed among the microsites and measured their abundances in three replicate wildfires and nearby unburned areas. We conducted a common-garden study in which soil cores from each burned microsite type were planted with seed of either species to determine microsite effects on establishment and growth of native and exotic grasses. We assessed soil physical properties in the common-garden study to determine the intrinsic properties of each microsite surface and the retention of microsite soil differences following transfer of soils to the garden, to plant growth, and to wetting/drying cycles. In the field study, only bluebunch wheatgrass density was greater on coppice mounds than interspaces, in both unburned and burned areas. In the common-garden experiment, there were microsite differences in soil physical properties, particularly in crust hardness and its relationship to moisture, but soil properties were unaffected by plant growth. Also in the experiment, both species had equal densities yet greater dry mass production on coppice-mound soils compared to interspace soils, suggesting microsite differences in growth but not establishment (likely related to crust weakening resulting from watering). Coppice-interspace patterning and specifically native-herb recovery on coppices is likely important for postfire resistance of this rangeland to cheatgrass.
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1983 biotic studies of Yucca Mountain, Nevada Test Site, Nye County, Nevada
International Nuclear Information System (INIS)
O'Farrell, T.P.; Collins, E.
1984-04-01
A 27.5-square-mile portion of Yucca Mountain on and adjacent to the US Department of Energy's Nevada Test Site, Nye County, Nevada, is being considered as a potential location for a national high-level radioactive waste repository. Preliminary geologic and environmental characterization studies have been supported and more extensive studies are planned. Goals of the biotic surveys were to identify species of concern, describe major floral and faunal associations, and assess possible impacts of characterization and operational activities. Floral associations observed were characteristic of either the Mojave or Transition deserts that are widely distributed in southern Nevada. Diversity, in terms of total number of perennial species represented, was higher in Transition Desert associations than in Mojave Desert associations. Canopy coverage of associations fell within the range of reported values, but tended to be more homogeneous than expected. Annual vegetation was found to be diverse only where the frequency of Bromus rubens was low. Ground cover of winter annuals, especially annual grasses, was observed to be very dense in 1983. The threat of range fires on Yucca Mountain was high because of the increased amount of dead litter and the decreased amount of bare ground. Significant variability was observed in the distribution and relative abundance of several small mammal species between 1982 and 1983. Desert tortoise were found in low densities comparable with those observed in 1982. Evidence of recent activity, which included sighting of two live tortoises, was found in five areas on Yucca Mountain. Two of these areas have a high probability of sustaining significant impacts if a repository is constructed. Regeneration of aboveground shrub parts from root crowns was observed in areas damaged in 1982 by seismic testing with Vibroseis machines. These areas, which had been cleared to bare dirt by passage of the machines, also supported lush stands of winter annuals
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Genetic resources of perennial forage grasses in Serbia: Current state, broadening and evaluation
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Sokolović Dejan
2017-01-01
Full Text Available Due to historical background of vegetation development, geographical position, climate and relief, Serbia represents one of the 158 world biodiversity centres, based upon the number of plant species and territory size (biodiversity index 0.72. Large areas in Serbia are under natural grasslands and pastures, composed of forage grass species, and important as source of natural plant genetic diversity and germplasm for breeding. These eco-systems represent basic prerequisites for sustainable forage production, but very low potential of them is utilized and genetic resources are not protected. Family Poaceae is present in Serbia flora with 70 genera and among them from the aspect of forage production and quality, the most important are perennial Festuca, Lolium, Dactylis, Phleum, Bromus, Arrhenatherum, Poa and Agrostis species. Most of these grasses have been bred in Serbia and lot of cultivars were released. These cultivars contain autochthonous Serbian material and represent great and important resource of genetic variability. Therefore, collecting of new samples which are acclimatised to local eco-geographical conditions and including them in plant ex situ gene bank is of exceptional importance for further utilization in different plant breeding programmes as well as genetic resources protection. These autochthonous populations have natural variability and very often have satisfactory yielding performance in comparison with introduced cultivars, which referred them for direct phenotypic selection for cultivars release. Broadening of forage grasses genotypes collection is permanent objective of Serbian scientists. Collected accessions are being characterized and evaluated for important phenological, morphological and agronomical traits. In this paper genetic resources of forage grass species, their diversity and potentials, state of the grasses gene banks, as well as possibility for breeding of new cultivars has been analysed.
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Assessing radiation exposure of herbaceous plant species at the East-Ural Radioactive Trace
International Nuclear Information System (INIS)
Karimullina, Elina; Antonova, Elena; Pozolotina, Vera
2013-01-01
The East-Ural Radioactive Trace (EURT) is a result of the Mayak Production Association accident that occurred in 1957 in Russia. Radiological assessment improves the interpretation of biological effects of exposure to ionizing radiation. Therefore a modeling approach was used to estimate dose rates on Leonurus quinquelobatus, Silene latifolia, Stellaria graminea and Bromus inermis. Soil-to-organism transfer parameter values are delivered from empirical data of 90 Sr and 137 Cs soil and vegetative plant mass activity concentrations. External and internal whole-body dose rates were calculated using deterministic (The ERICA Tool-Tier 2 and R and D 128/SP1a) and probabilistic (The ERICA Tool-Tier 3) methods. The total dose rate for herbs was under 100 μGy h −1 at the most polluted site. The total absorbed dose rates increased 43–110 times (Tier 3) for different herbaceous plant species along the pollution gradient. Based on these data, it can be concluded that herbaceous plant populations currently exist under low-level chronic exposure at the EURT area. -- Highlights: • A modeling approach (The ERICA Tool-Tier 2, Tier 3 and R and D 128/SP1a) was used to estimate dose rates for herbs growing in the wild at the East-Ural Radioactive Trace. • The highest levels of anthropogenic radiation exposure were determined for herbs at Impact EURT sites. • Total absorbed dose rates increased 43–110 times (Tier 3) for different herbaceous plant species along the pollution gradient. • Total dose rate per plant organism for herbs is under 100 μGy h −1 at the most polluted site. Currently herbaceous plant populations exist under low-level chronic exposure at the EURT area
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Yu, Kailiang; D'Odorico, Paolo; Carr, David E; Personius, Ashden; Collins, Scott L
2017-10-01
Plants with crassulacean acid metabolism (CAM) are increasing their abundance in drylands worldwide. The drivers and mechanisms underlying the increased dominance of CAM plants and CAM expression (i.e., nocturnal carboxylation) in facultative CAM plants, however, remain poorly understood. We investigated how nutrient and water availability affected competition between Mesembryanthemum crystallinum (a model facultative CAM species) and the invasive C 3 grass Bromus mollis that co-occur in California's coastal grasslands. Specifically we investigated the extent to which water stress, nutrients, and competition affect nocturnal carboxylation in M. crystallinum . High nutrient and low water conditions favored M. crystallinum over B. mollis , in contrast to high water conditions. While low water conditions induced nocturnal carboxylation in 9-week-old individuals of M. crystallinum , in these low water treatments, a 66% reduction in nutrient applied over the entire experiment did not further enhance nocturnal carboxylation. In high water conditions M. crystallinum both alone and in association with B. mollis did not perform nocturnal carboxylation, regardless of the nutrient levels. Thus, nocturnal carboxylation in M. crystallinum was restricted by strong competition with B. mollis in high water conditions. This study provides empirical evidence of the competitive advantage of facultative CAM plants over grasses in drought conditions and of the restricted ability of M. crystallinum to use their photosynthetic plasticity (i.e., ability to switch to CAM behavior) to compete with grasses in well-watered conditions. We suggest that a high drought tolerance could explain the increased dominance of facultative CAM plants in a future environment with increased drought and nitrogen deposition, while the potential of facultative CAM plants such as M. crystallinum to expand to wet environments is expected to be limited.
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Indirect effects of an invasive annual grass on seed fates of two native perennial grass species.
Meyer, Susan E; Merrill, Katherine T; Allen, Phil S; Beckstead, Julie; Norte, Anna S
2014-04-01
Invasive plants exhibit both direct and indirect negative effects on recruitment of natives following invasion. We examined indirect effects of the invader Bromus tectorum (cheatgrass) on seed fates of two native grass species, Elymus elymoides and Pseudoroegneria spicata, by removing B. tectorum and by adding inoculum of the shared seed pathogen Pyrenophora semeniperda in factorial experiments at xeric and mesic field sites. We also included a supplemental watering treatment to increase emergence and also the potential for pathogen escape. We recorded emergence and survival of native seedlings and also determined the fate of unemerged seeds. At the xeric site, Pyrenophora-caused mortality was high (34%), and effects of other pathogens and failed emergence of germinants were smaller. Cheatgrass removal negatively affected both emergence (35 vs. 25%) and spring survival (69 vs. 42%). Pyrenophora-caused seed mortality increased with inoculum augmentation for both species (22 vs. 47% overall), but emergence was negatively impacted only for P. spicata (20 vs. 34%). At the mesic site, Pyrenophora-caused mortality was low (6%). Cheatgrass removal doubled emergence (26 vs. 14%). Seed mortality increased significantly with inoculum augmentation for P. spicata (12 vs. 5%) but not E. elymoides, while emergence was not significantly affected in either species. A large fraction of seeds produced germinants that failed to emerge (37%), while another large fraction (35%) was killed by other pathogens. We conclude that facilitation by cheatgrass at the xeric site but interference at the mesic site was probably mediated through litter effects that could be ameliorative or suppressive. Apparent competition between cheatgrass and native grasses could occur through Pyrenophora, especially in a xeric environment, but effects were weak or absent at emergence. This was probably because Pyrenophora attacks the same slow-germinating fraction that is subject to pre-emergence mortality from
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Magnoli, Susan M; Kleinhesselink, Andrew R; Cushman, J Hall
2013-12-01
The spread of exotic, invasive species is a global phenomenon that is recognized as a major source of environmental change. Although many studies have addressed the effects of exotic plants on the communities they invade, few have quantified the effects of invader removal on plant communities, or considered the degree to which different plant groups vary in response to invasion and invader removal. We evaluated the effects of an exotic succulent, iceplant (Carpobrotus edulis), on a coastal dune plant community in northern California, as well as the community responses to its removal. To assess possible mechanisms by which iceplant affects other plants, we also evaluated its above- and belowground influences on the germination and growth of a dominant exotic annual grass, Bromus diandrus. We found that iceplant invasion was associated with reduced native plant cover as well as increased cover and density of some exotic plants-especially exotic annual grasses. However, iceplant removal did not necessarily lead to a reversal of these effects: removal increased the cover and density of both native and exotic species. We also found that B. diandrus grown in iceplant patches, or in soil where iceplant had been removed, had poorer germination and growth than B. diandrus grown in soil not influenced by iceplant. This suggests that the influence of iceplant on this dune plant community occurs, at least in part, due to belowground effects, and that these effects remain after iceplant has been removed. Our study demonstrates the importance of considering how exotic invasive plants affect not only native species, but also co-occurring exotic taxa. It also shows that combining observational studies with removal experiments can lead to important insights into the influence of invaders and the mechanisms of their effects.
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Effect of Time and Burial Depth on Breaking Seed dormancy and Germination of Weed Seeds
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marzie mazhari
2016-02-01
Full Text Available Introduction: Weeds limit crop growth, development and yield through competing. Seed bank of weeds in field is one of the sources which can affect weed management and their control methods. Environmental conditions during seed maturation and following dispersal interact to influence the germination phenology of many species. Disturbance plays a key role in the maintenance of habitat for many plant species, particularly referrals, for example, fire ephemerals, desert annuals, and arable weeds. Seed germination and emergence depend on endogenous and exogenous factors. Viable seeds are dormant when all environmental conditions are appropriate for germination but seeds fail to germinate. Thus, dormancy plays an important ecological role in preventing seed germination, being a major contributor to seed persistence of some species in soil. Buried seeds of annual weeds are certainly subjected to different soil moisture conditions during their dormancy release season (winter according to the annual rainfall pattern and burial depth. Shallow buried seeds are exposed to soil moisture fluctuations that could affect their dormancy status. Laboratory studies showed that desiccation and subsequent re-hydration of seeds could stimulate germination and modify seed light requirements. Seeds buried in deeper layers of the soil would not be exposed to such fluctuations in soil moisture, but would be exposed to different soil moisture environments depending on weather and soil characteristics. The effects of interactions between temperature, and soil or seed moisture, on seed dormancy changes have been reported for several species. Therefore, the objectives of this study were to determine the effect of time and burial depth treatments on seed germination and seedling emergence of Aegilops cylindrica, Agropyrom repens, Avena fatua, Bromus dantoniae, Cynodon dactylon, Cyprus rotundus, Setaria viridis, Anthriscus sylvestris, Centurea cyanus. Materials and Methods: In
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JAVIER A FIGUEROA
2012-03-01
Full Text Available We studied the effect of heat shock and wood-fueled smoke on the emergence of native and exotic plant species in soil samples obtained in an evergreen matorral of central Chile that has been free of fire for decades. It is located on the eastern foothills of the Andes Range in San Carlos de Apoquindo. Immediately after collection samples were dried and stored under laboratory conditions. For each two transect, ten samples were randomly chosen, and one of the following treatments was applied: (1 heat-shock treatment, (2 plant-produced smoke treatment, (3 combined heat-and-smoke treatment, and (4 control, corresponding to samples not subjected to treatment. Twenty-seven species, representing 13 families, emerged from the soil samples. The most abundant families were Asteraceae and Poaceae. All of the emerged species were herbaceous, and 18 species were exotic. Respect to general hypothesis, there is no evidence for the proposition that fire-free matorral has lower proportion of exotic and native species with fire-related cues than matorral with fires. Among the exotic and native, the mean number of species that emerged from soil samples did not change significantly with respect to the control for any of the treatments applied. Nevertheless, important species-specific responses were observed. Smoke and heat-smoke combination significantly increased the emergence of the exotic species Anthriscus caucalis. While smoke-related cues significantly increased the emergence of the exotic species Avena barbata, the emergence of the exotic Aphanes arvensis and the native Bromus berteroanus decreases. For several species our results showed inconsistent responses to fire-related cues compared to those reported in the literature. We suggest that these differences might be related with the fire-history in the populations, an important issue poorly acknowledge in the literature.Nosotros estudiamos el efecto del golpe de calor y del humo de la combustión de
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Ali gazanchian
2017-10-01
Full Text Available Introduction Drought is a natural phenomenon in arid and semi-arid regions of the world. It is created by low precipitation, high evaporation and reduced soil moisture. Today, they are the major threats to agricultural lands due to fluctuations in rainfall, limited water resources, wells salinization and subsequently abandoned farming lands. Iran is located on the world's dry belt and more than 90 percent of its area is located in the arid and semi-arid climatic regions. It has been reported that the annual rate of soil erosion is up to 33 tons per hectare and 5 to 6 times more than the standard limit. Also, 90% of the country's protein production comes from animals sources. Due to the lack of adequate forage production, the main burden of protein production is imposed on the natural resources and pastures. Therefore, In order to enhance soil stabilization and maintain its fertility, optimum use of off-season precipitations, preventing the flow of water and protecting the abandoned farming lands from the flood risk, increasing the water permeability in the soil, and helping to feed the underwater aquifers and finally the production of forage and seeds, the development of perennial plants cultivation is an important conservative practice. The aim of this study is to emphasize on the selection of the best perennial forage species with low water requirements and acceptable performance for renovation of the abandoned farming lands and moving towards sustainable agriculture approaches. Materials and Methods In this experiment, 10 species of perennial grasses (Agropyron elongatum Host., Secale montanum Guss., Festuca arundinaceae Schreb., Dactylis glomerata L., Agropyron intermedium Host., Agropyron repense L., Agropyron cristatum L., Panicum antidutale Retz., Bromus inermis Leyss., Bromus riparius Rehmann, Agropyron cristatum L. and two legumes includes Trifolium pratense L., Onobrychis sativa Lam. were studied at Asatan-e-Ghods Razavi farm in
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Species’ traits help predict small mammal responses to habitat homogenization by an invasive grass
Ceradini, Joseph P.; Chalfoun, Anna D.
2017-01-01
Invasive plants can negatively affect native species, however, the strength, direction, and shape of responses may vary depending on the type of habitat alteration and the natural history of native species. To prioritize conservation of vulnerable species, it is therefore critical to effectively predict species’ responses to invasive plants, which may be facilitated by a framework based on species’ traits. We studied the population and community responses of small mammals and changes in habitat heterogeneity across a gradient of cheatgrass (Bromus tectorum) cover, a widespread invasive plant in North America. We live-trapped small mammals over two summers and assessed the effect of cheatgrass on native small mammal abundance, richness, and species-specific and trait-based occupancy, while accounting for detection probability and other key habitat elements. Abundance was only estimated for the most common species, deer mice (Peromyscus maniculatus). All species were pooled for the trait-based occupancy analysis to quantify the ability of small mammal traits (habitat association, mode of locomotion, and diet) to predict responses to cheatgrass invasion. Habitat heterogeneity decreased with cheatgrass cover. Deer mouse abundance increased marginally with cheatgrass. Species richness did not vary with cheatgrass, however, pocket mouse (Perognathus spp.) and harvest mouse (Reithrodontomys spp.) occupancy tended to decrease and increase, respectively, with cheatgrass cover, suggesting a shift in community composition. Cheatgrass had little effect on occupancy for deer mice, 13-lined ground squirrels (Spermophilus tridecemlineatus), and Ord's kangaroo rat (Dipodomys ordii). Species’ responses to cheatgrass primarily corresponded with our a priori predictions based on species’ traits. The probability of occupancy varied significantly with a species’ habitat association but not with diet or mode of locomotion. When considered within the context of a rapid
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Energy Technology Data Exchange (ETDEWEB)
Jasrow, J. D.; Zimmerman, C. A.; Dvorak, A. J.; Hinchman, R. R.
1979-10-01
Two commonly used revegetation species, Kentucky 31 tall fescue (Festuca arundinacea Schreb.) and Lincoln smooth brome (Bromus inermis Leyss.) were grown for 60 days in pots containing coarse coal mine refuse (referred to as gob, pH = 3.5) that was amended with lime or alkaline fly ash. Both species were also grown in pots containing a silt-loam surface soil as a control. Morphological growth parameters were measured over time; dry weights and shoot:root ratios were determined at harvest. Concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn in the plant shoots were determined by atomic absorption spectrophotometry. Plant growth of both species was not as good on either lime- or fly ash-amended gob as it was on surface soil. Although plant height and length of the longest lead were not significantly different (p > 0.10) at the end of the experiment for plants grown on the two amended-gob substrates, parameters giving an indication of plant vigor (i.e., number of leaves and stems, width of the longest lead, and biomass) were significantly greater (p < 0.01) for plants grown on lime-amended gob than for those grown on fly ash-amended gob. Significant (p < 0.05) differences in the tissue concentrations of Cd, Co, Fe, Hg, Mn, Pb, V, and Zn were found among the plants grown on the three substrates. Except for Hg and Pb, these elements were higher in plants grown on at least one of the amended-gob substrates than in plants grown on surface soil. Significant substrate differences were not observed for Al, As, Cr, Cu, Ni, and Se. The tissue concentrations of some elements - notably Al, Cu, Fe, Mn, V, and Zn - were high enough in plants from one or more of the substrates to either approach or exceed concentrations that have been reported to be associated with toxic effects in some plant species.
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Zhou, Qiang
Over the past two decades, non-native species within grassland communities have quickly developed due to human migration and commerce. Invasive species like Smooth Brome grass (Bromus inermis) and Kentucky Blue Grass (Poa pratensis), seriously threaten conservation of native grasslands. This study aims to discriminate between native grasslands and planted hayfields and conservation areas dominated by introduced grasses using hyperspectral imagery. Hyperspectral imageries from the Hyperion sensor on EO-1 were acquired in late spring and late summer on 2009 and 2010. Field spectra for widely distributed species as well as smooth brome grass and Kentucky blue grass were collected from the study sites throughout the growing season. Imagery was processed with an unmixing algorithm to estimate fractional cover of green and dry vegetation and bare soil. As the spectrum is significantly different through growing season, spectral libraries for the most common species are then built for both the early growing season and late growing season. After testing multiple methods, the Adaptive Coherence Estimator (ACE) was used for spectral matching analysis between the imagery and spectral libraries. Due in part to spectral similarity among key species, the results of spectral matching analysis were not definitive. Additional indexes, "Level of Dominance" and "Band variance", were calculated to measure the predominance of spectral signatures in any area. A Texture co-occurrence analysis was also performed on both "Level of Dominance" and "Band variance" indexes to extract spatial characteristics. The results suggest that compared with disturbed area, native prairie tend to have generally lower "Level of Dominance" and "Band variance" as well as lower spatial dissimilarity. A final decision tree model was created to predict presence of native or introduced grassland. The model was more effective for identification of Mixed Native Grassland than for grassland dominated by a single
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Miriti, Maria N; Ibrahim, Tahir; Palik, Destiny; Bonin, Catherine; Heaton, Emily; Mutegi, Evans; Snow, Allison A
2017-08-01
Perennial grasses are promising candidates for bioenergy crops, but species that can escape cultivation and establish self-sustaining naturalized populations (feral) may have the potential to become invasive. Fertile Miscanthus × giganteus , known as "PowerCane," is a new potential biofuel crop. Its parent species are ornamental, non-native Miscanthus species that establish feral populations and are sometimes invasive in the USA. As a first step toward assessing the potential for "PowerCane" to become invasive, we documented its growth and fecundity relative to one of its parent species ( Miscanthus sinensis ) in competition with native and invasive grasses in common garden experiments located in Columbus, Ohio and Ames, Iowa, within the targeted range of biofuel cultivation. We conducted a 2-year experiment to compare growth and reproduction among three Miscanthus biotypes-"PowerCane," ornamental M. sinensis , and feral M. sinensis -at two locations. Single Miscanthus plants were subjected to competition with a native grass ( Panicum virgatum ), a weedy grass ( Bromus inermis ), or no competition. Response variables were aboveground biomass, number of shoots, basal area, and seed set. In Iowa, all Miscanthus plants died after the first winter, which was unusually cold, so no further results are reported from the Iowa site. In Ohio, we found significant differences among biotypes in growth and fecundity, as well as significant effects of competition. Interactions between these treatments were not significant. "PowerCane" performed as well or better than ornamental or feral M. sinensis in vegetative traits, but had much lower seed production, perhaps due to pollen limitation. In general, ornamental M. sinensis performed somewhat better than feral M. sinensis . Our findings suggest that feral populations of "PowerCane" could become established adjacent to biofuel production areas. Fertile Miscanthus × giganteus should be studied further to assess its
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Floristic changes at Khersan Glacier Territory, Alamkuh Mountain, Central Alborz, North of Iran
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KOUROSH KAVOUSI
2016-02-01
Full Text Available Abstract. Kavousi K, Nejadsattari T, Asri Y, Ejtehadi H, Khavari-Nejad RA. 2016. Floristic changes at Khersan Glacier Territory, Alamkuh Mountain, Central Alborz, North of Iran. Biodiversitas 17: 11-15. Extensive investigation in subnival-nival area around Khersan glacier moraine introduced 71 vascular plant species. From this list 43 species have been listed in Noroozi (2001 in “ subnival-nival vascular plant species of Iran : a unique high mountain flora and its threat from climate warming ” and the others are new for subnival- nival area of Iran. Among this plant list 31 species had introduced with Kotschy (1861a,b, Bornmuller (1904, Melchior (1937, Klein (1982, european researchers and the other is named for the first time from Khersan glacier territory. Many species such as Astragalus macrosemius, Pseudocamelina kleinii, Crepis multicaulis subsp. congesta, Didymophysa fedtschenkoana and Draba melanopus due to glacier condition have very sensitive habitat, vulnerable and only gathered from restrict area with conservation value. Vegetation change happened in many nival and subnival area with upward movement in the same habitat and movement from lower altitude at alpine towards summit in subnival and nival. Carex oreophila, Campanula stevenii, Bromus barchystachyus, Oxytropis immersa, Erigeron uniflorus,Trachydium pauciradiatum, Scorzonera radicosa and some other species are surprisingly movement to subnival area and many nival and subnival species such as Didymophysa aucheri, Didymophysa fedtschenkoana, Dracocephalum aucheri and Arabis caucasica have come significantly upward in nival. The movement is different in all side of Khersan glacier moraine in north, south and the east (beside moraine tongue slops and limited with presence of soil natural generation and other ecological remarks. Limitation for soil generation starts at different altitude in northern, southern and eastern slopes of Khersan glacier valley. This study examined
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Riparian Vegetation Mapping Along the Hanford Reach
International Nuclear Information System (INIS)
FOGWELL, T.W.
2003-01-01
During the biological survey and inventory of the Hanford Site conducted in the mid-1990s (1995 and 1996), preliminary surveys of the riparian vegetation were conducted along the Hanford Reach. These preliminary data were reported to The Nature Conservancy (TNC), but were not included in any TNC reports to DOE or stakeholders. During the latter part of FY2001, PNNL contracted with SEE Botanical, the parties that performed the original surveys in the mid 1990s, to complete the data summaries and mapping associated with the earlier survey data. Those data sets were delivered to PNNL and the riparian mapping by vegetation type for the Hanford Reach is being digitized during the first quarter of FY2002. These mapping efforts provide the information necessary to create subsequent spatial data layers to describe the riparian zone according to plant functional types (trees, shrubs, grasses, sedges, forbs). Quantification of the riparian zone by vegetation types is important to a number of DOE'S priority issues including modeling contaminant transport and uptake in the near-riverine environment and the determination of ecological risk. This work included the identification of vegetative zones along the Reach by changes in dominant plant species covering the shoreline from just to the north of the 300 Area to China Bar near Vernita. Dominant and indicator species included Agropyron dasytachyudA. smithii, Apocynum cannabinum, Aristida longiseta, Artemisia campestris ssp. borealis var scouleriana, Artemisa dracunculus, Artemisia lindleyana, Artemisia tridentata, Bromus tectorum, Chrysothamnus nauseosus, Coreopsis atkinsoniana. Eleocharis palustris, Elymus cinereus, Equisetum hyemale, Eriogonum compositum, Juniperus trichocarpa, Phalaris arundinacea, Poa compressa. Salk exigua, Scirpus acutus, Solidago occidentalis, Sporobolus asper,and Sporobolus cryptandrus. This letter report documents the data received, the processing by PNNL staff, and additional data gathered in FY2002
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Ostoja, Steven M.; Schupp, Eugene W.; Klinger, Rob
2013-01-01
Granivore foraging decisions affect consumer success and determine the quantity and spatial pattern of seed survival. These decisions are influenced by environmental variation at spatial scales ranging from landscapes to local foraging patches. In a field experiment, the effects of seed patch variation across three spatial scales on seed removal by western harvester ants Pogonomyrmex occidentalis were evaluated. At the largest scale we assessed harvesting in different plant communities, at the intermediate scale we assessed harvesting at different distances from ant mounds, and at the smallest scale we assessed the effects of interactions among seed species in local seed neighborhoods on seed harvesting (i.e. resource–consumer interface). Selected seed species were presented alone (monospecific treatment) and in mixture with Bromus tectorum (cheatgrass; mixture treatment) at four distances from P. occidentalis mounds in adjacent intact sagebrush and non-native cheatgrass-dominated communities in the Great Basin, Utah, USA. Seed species differed in harvest, with B. tectorum being least preferred. Large and intermediate scale variation influenced harvest. More seeds were harvested in sagebrush than in cheatgrass-dominated communities (largest scale), and the quantity of seed harvested varied with distance from mounds (intermediate-scale), although the form of the distance effect differed between plant communities. At the smallest scale, seed neighborhood affected harvest, but the patterns differed among seed species considered. Ants harvested fewer seeds from mixed-seed neighborhoods than from monospecific neighborhoods, suggesting context dependence and potential associational resistance. Further, the effects of plant community and distance from mound on seed harvest in mixtures differed from their effects in monospecific treatments. Beyond the local seed neighborhood, selection of seed resources is better understood by simultaneously evaluating removal at
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Drake, Brandon L; Hanson, David T; Lowrey, Timothy K; Sharp, Zachary D
2017-02-01
From 1890 to 2015, anthropogenic carbon dioxide emissions have increased atmospheric CO 2 concentrations from 270 to 400 mol mol -1 . The effect of increased carbon emissions on plant growth and reproduction has been the subject of study of free-air CO 2 enrichment (FACE) experiments. These experiments have found (i) an increase in internal CO 2 partial pressure (c i ) alongside acclimation of photosynthetic capacity, (ii) variable decreases in stomatal conductance, and (iii) that increases in yield do not increase commensurate with CO 2 concentrations. Our data set, which includes a 115-year-long selection of grasses collected in New Mexico since 1892, is consistent with an increased c i as a response to historical CO 2 increase in the atmosphere, with invasive species showing the largest increase. Comparison with Palmer Drought Sensitivity Index (PDSI) for New Mexico indicates a moderate correlation with Δ 13 C (r 2 = 0.32, P < 0.01) before 1950, with no correlation (r 2 = 0.00, P = 0.91) after 1950. These results indicate that increased c i may have conferred some drought resistance to these grasses through increased availability of CO 2 in the event of reduced stomatal conductance in response to short-term water shortage. Comparison with C 3 trees from arid environments (Pinus longaeva and Pinus edulis in the US Southwest) as well as from wetter environments (Bromus and Poa grasses in New Mexico) suggests differing responses based on environment; arid environments in New Mexico see increased intrinsic water use efficiency (WUE) in response to historic elevated CO 2 while wetter environments see increased c i . This study suggests that (i) the observed increases in c i in FACE experiments are consistent with historical CO 2 increases and (ii) the CO 2 increase influences plant sensitivity to water shortage, through either increased WUE or c i in arid and wet environments, respectively. © 2016 John Wiley & Sons Ltd.
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Riparian Vegetation Mapping Along the Hanford Reach
Energy Technology Data Exchange (ETDEWEB)
FOGWELL, T.W.
2003-07-11
During the biological survey and inventory of the Hanford Site conducted in the mid-1990s (1995 and 1996), preliminary surveys of the riparian vegetation were conducted along the Hanford Reach. These preliminary data were reported to The Nature Conservancy (TNC), but were not included in any TNC reports to DOE or stakeholders. During the latter part of FY2001, PNNL contracted with SEE Botanical, the parties that performed the original surveys in the mid 1990s, to complete the data summaries and mapping associated with the earlier survey data. Those data sets were delivered to PNNL and the riparian mapping by vegetation type for the Hanford Reach is being digitized during the first quarter of FY2002. These mapping efforts provide the information necessary to create subsequent spatial data layers to describe the riparian zone according to plant functional types (trees, shrubs, grasses, sedges, forbs). Quantification of the riparian zone by vegetation types is important to a number of DOE'S priority issues including modeling contaminant transport and uptake in the near-riverine environment and the determination of ecological risk. This work included the identification of vegetative zones along the Reach by changes in dominant plant species covering the shoreline from just to the north of the 300 Area to China Bar near Vernita. Dominant and indicator species included Agropyron dasytachyudA. smithii, Apocynum cannabinum, Aristida longiseta, Artemisia campestris ssp. borealis var scouleriana, Artemisa dracunculus, Artemisia lindleyana, Artemisia tridentata, Bromus tectorum, Chrysothamnus nauseosus, Coreopsis atkinsoniana. Eleocharis palustris, Elymus cinereus, Equisetum hyemale, Eriogonum compositum, Juniperus trichocarpa, Phalaris arundinacea, Poa compressa. Salk exigua, Scirpus acutus, Solidago occidentalis, Sporobolus asper,and Sporobolus cryptandrus. This letter report documents the data received, the processing by PNNL staff, and additional data gathered in FY
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Uptake and distribution of Pu, Am, Cm and Np in four plant species
Energy Technology Data Exchange (ETDEWEB)
Schreckhise, R G; Cline, J F [Battelle, Pacific Northwest Laboratories, Richland, WA (United States)
1978-12-01
The relative uptake of the nitrate forms of {sup 238}Pu, {sup 239}Pu, {sup 241}Sm, {sup 244}Cm and {sup 237}Np from soil into selectee parts of four different plant species grown under field conditions were observed. Cheatgrass (Bromus tectorum L.), peas (Pisum sativum, var. Blue Bonnet), barley (Hordeum vulgare, var. U. Cal. Briggs), and alfalfa (Medicago sativa, var. Ranger) were grown outdoors in contaminated soil contained in small weighing lysimeters constructed from 13.2 cm diameter by 1-meter-long polyvinyl chloride pipe. The amended soil, containing 0.1 to 1.0 mCi of each isotope individually per 3.4 kg soil, was situated in a 20 cm band and covered by 10 cm of uncontaminated soil to eliminate chances of windblown contamination to the surrounding environs. The plants were harvested at maturity, divided into selected components and radiochemically analyzed by alpha-energy analysis. There did not appear to be any effect of soil concentration on the plant uptake of {sup 238}Pu, {sup 239}Pu, {sup 241}Am or {sup 244}Cm for the two levels utilized (approximately 0.03 and 0.3 {mu}Ci/g soil). The relative uptake of {sup 238}Pu and {sup 239}Pu were not significantly different. Likewise, {sup 241} Am uptake values were not significantly different from the {sup 244}Cm values. The relative plant uptake of the four different transuranium element was: Np > Cm {approx} Am > Pu. The relative uptake values of Np were 2,200 to 45,000 times greater than for Pu, while Am and Cm values were 10 to 20 times greater. The seeds were significantly lower than the rest of the above ground plant parts for all four transuranics. The legumes accumulated approximately ten times more than the grasses. A hypothetical comparison of the radionuclide content of plants grown in soil contaminated with LMFBR fuels indicate that Am, Cm and Np concentrations would exceed Pu values. (author)
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Directory of Open Access Journals (Sweden)
Robert A. Miller
2016-06-01
Full Text Available The Short-eared Owl (Asio flammeus is an open-country species breeding in the northern United States and Canada, and has likely experienced a long-term, range-wide, and substantial decline. However, the cause and magnitude of the decline is not well understood. We set forth to address the first two of six previously proposed conservation priorities to be addressed for this species: (1 better define habitat use and (2 improve population monitoring. We recruited 131 volunteers to survey over 6.2 million ha within the state of Idaho for Short-eared Owls during the 2015 breeding season. We surveyed 75 transects, 71 of which were surveyed twice, and detected Short-eared Owls on 27 transects. We performed multiscale occupancy modeling to identify habitat associations, and performed multiscale abundance modeling to generate a state-wide population estimate. Our results suggest that within the state of Idaho, Short-eared Owls are more often found in areas with marshland or riparian habitat or areas with greater amounts of sagebrush habitat at the 1750 ha transect scale. At the 50 ha point scale, Short-eared Owls tend to associate positively with fallow and bare dirt agricultural land and negatively with grassland. Cropland was not chosen at the broader transect scale suggesting that Short-eared Owls may prefer more heterogeneous landscapes. On the surface our results may seem contradictory to the presumed land use by a "grassland" species; however, the grasslands of the Intermountain West, consisting largely of invasive cheatgrass (Bromus tectorum, lack the complex structure shown to be preferred by these owls. We suggest the local adaptation to agriculture represents the next best habitat to their historical native habitat preferences. Regardless, we have confirmed regional differences that should be considered in conservation planning for this species. Last, our results demonstrate the feasibility, efficiency, and effectiveness of utilizing public
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CO2 EFFECTS ON MOJAVE DESERT PLANT INTERACTIONS
Energy Technology Data Exchange (ETDEWEB)
L. A. DEFALCO; G. C. FERNANDEZ; S. D. SMITH; R. S. NOWAK
2004-01-01
Seasonal and interannual droughts characteristic of deserts have the potential to modify plant interactions as atmospheric CO{sub 2} concentrations continue to rise. At the Nevada Desert FACE (free-air CO{sub 2} enrichment) facility in the northern Mojave Desert, the effects of elevated atmospheric C02 (550 vs. ambient {approx}360 {micro}mol mol{sup -1}) on plant interactions were examined during two years of high and low rainfall. Results suggest that CO{sub 2} effects on the interaction between native species and their understory herbs are dependent on the strength of competition when rainfall is plentiful, but are unimportant during annual drought. Seasonal rainfall for 1999 was 23% the long-term average for the area, and neither elevated CO{sub 2} nor the low production of herbaceous neighbors had an effect on relative growth rate (RGR, d{sup -1}) and reproductive effort (RE, number of flowers g{sup -1}) for Achnatherum hymenoides (early season perennial C{sub 3} grass), Pleuraphis rigida (late season perennial C{sub 4} grass), and Larrea tridentata (evergreen C{sub 3} shrub). In contrast, 1998 received 213% the average rainfall. Consequently, the decrease in RGR and increase in RE for Achnatherum, whose period of growth overlaps directly with that of its neighbors, was exaggerated at elevated CO{sub 2}. However, competitive effects of neighbors on Eriogonum trichopes (a winter annual growing in shrub interspaces), Pleuraphis and Larrea were not affected by elevated CO{sub 2}, and possible explanations are discussed. Contrary to expectations, the invasive annual neighbor Bromus madritensis ssp. rubens had little influence on target plant responses because densities in 1998 and 1999 at this site were well below those found in other studies where it has negatively affected perennial plant growth. The extent that elevated CO{sub 2} reduces the performance of Achnatherum in successive years to cause its loss from the plant community depends more on future pressure
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Vegetation Response to Western Juniper Slash Treatments
O'Connor, Casey; Miller, Rick; Bates, Jonathan D.
2013-09-01
The expansion of piñon-juniper woodlands the past 100 years in the western United States has resulted in large scale efforts to kill trees and recover sagebrush steppe rangelands. It is important to evaluate vegetation recovery following woodland control to develop best management practices. In this study, we compared two fuel reduction treatments and a cut-and-leave (CUT) treatment used to control western juniper ( Juniperus occidentalis spp. occidentalis Hook.) of the northwestern United States. Treatments were; CUT, cut-and-broadcast burn (BURN), and cut-pile-and-burn the pile (PILE). A randomized complete block design was used with five replicates of each treatment located in a curl leaf mahogany ( Cercocarpus ledifolius Nutt. ex Torr. & A. Gray)/mountain big sagebrush ( Artemisia tridentata Nutt. spp. vaseyana (Rydb.) Beetle)/Idaho fescue ( Festuca idahoensis Elmer) association. In 2010, 4 years after tree control the cover of perennial grasses (PG) [Sandberg's bluegrass ( Poa secunda J. Pres) and large bunchgrasses] were about 4 and 5 % less, respectively, in the BURN (7.1 ± 0.6 %) than the PILE (11.4 ± 2.3 %) and CUT (12.4 ± 1.7 %) treatments ( P < 0.0015). In 2010, cover of invasive cheatgrass ( Bromus tectorum L.) was greater in the BURN (6.3 ± 1.0 %) and was 50 and 100 % greater than PILE and CUT treatments, respectively. However, the increase in perennial bunchgrass density and cover, despite cheatgrass in the BURN treatment, mean it unlikely that cheatgrass will persist as a major understory component. In the CUT treatment mahogany cover increased 12.5 % and density increased in from 172 ± 25 to 404 ± 123 trees/ha. Burning, killed most or all of the adult mahogany, and mahogany recovery consisted of 100 and 67 % seedlings in the PILE and BURN treatments, respectively. After treatment, juniper presence from untreated small trees (<1 m tall; PILE and CUT treatments) and seedling emergence (all treatments) represented 25-33 % of pre-treatment tree
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Connolly, B M; Pearson, D E; Mack, R N
2014-07-01
Seed predation is an important biotic filter that can influence abundance and spatial distributions of native species through differential effects on recruitment. This filter may also influence the relative abundance of nonnative plants within habitats and the communities' susceptibility to invasion via differences in granivore identity, abundance, and food preference. We evaluated the effect of postdispersal seed predators on the establishment of invasive, naturalized, and native species within and between adjacent forest and steppe communities of eastern Washington, USA that differ in severity of plant invasion. Seed removal from trays placed within guild-specific exclosures revealed that small mammals were the dominant seed predators in both forest and steppe. Seeds of invasive species (Bromus tectorum, Cirsium arvense) were removed significantly less than the seeds of native (Pseudoroegneria spicata, Balsamorhiza sagittata) and naturalized (Secale cereale, Centaurea cyanus) species. Seed predation limited seedling emergence and establishment in both communities in the absence of competition in a pattern reflecting natural plant abundance: S. cereale was most suppressed, B. tectorum was least suppressed, and P. spicata was suppressed at an intermediate level. Furthermore, seed predation reduced the residual seed bank for all species. Seed mass correlated with seed removal rates in the forest and their subsequent effects on plant recruitment; larger seeds were removed at higher rates than smaller seeds. Our vegetation surveys indicate higher densities and canopy cover of nonnative species occur in the steppe compared with the forest understory, suggesting the steppe may be more susceptible to invasion. Seed predation alone, however, did not result in significant differences in establishment for any species between these communities, presumably due to similar total small-mammal abundance between communities. Consequently, preferential seed predation by small
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International Nuclear Information System (INIS)
Stas, J.; Dahdouh, A.; Rizkallah, I.
2010-01-01
The extraction of vanadium and molybdenum from alkaline leaching solutions coming from the leaching of fly ash of fired electrical power stations by tri-n dodecylamine (TDA) and metyl trioctyl ammonium chloride (QA) in the presence of octanol-2 as modifier in kerosene has been investigated. Some parameters influencing the extraction process have been studied (agitation time, octanol-2 percentage in the organic phase, pH of the aqueous phase, concentration of TDA and QA, concentration of vanadium in the aqueous phase and temperature). It has been shown that the extraction capacity of both V and Mo by TDA increases by decreasing the pH of the aqueous phase and reaches a maximum extraction at pH=2. The concentration of TDA plays an important role on the separation selectivity between these two elements, where the selectivity of Mo vs V (S M o, v=[Mo] o rg/[V] o rg) increases with the decrease of TDA concentration to reach a maximum selectivity value of S M o, v = 0.37 for [TDA]=1.5 M. It has been also shown that, whatever vanadium concentration in the aqueous phase, molybdenum will be first extracted, then the remaining free TDA will be occupied by vanadium. Concerning the quaternary amine QA, the pH value of the aqueous phase plays an important role in the separation process between vanadium and molybdenum, where the value of the selectivity of V vs Mo (S v , Mo=[V] o rg/[Mo] o rg) is maximal for pH>8 and the pH=8.5 is the best value which permit a good separation between these two elements at QA concentration equal to 6%, especially at high vanadium concentration. It is very important to note that for low vanadium concentration and at pH=1.5 the value of the selectivity of Mo vs V (S M o,v) increases with increasing Mo concentration in the aqueous phase which enable us the separation between these two elements under these experimental conditions, where Mo will be much more extracted than vanadium. The stripping of vanadium and molybdenum from the loaded organic
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Directory of Open Access Journals (Sweden)
Pedro Andreo-Martínez
2016-10-01
Full Text Available The wastewater generated by isolated houses without access to public sewers can cause environmental problems, like the contamination of aquifers with nitrates and phosphates, as occurs in southeastern Spain. The effectiveness of a previously built horizontal subsurface flow constructed wetland (HF-CW was studied over two years as a possible solution. This HF-CW measured 27 m2; it was planted with Phragmites australis(Cav. Trin. Ex Steuds sp. Altissima and the parameters studied were those required by European Union (EU legislation and adopted by Spain. Average abatement efficiency rates, for the first and the second year of study, were: biochemical oxygen demand over five days (BOD5 (96.4%, 92.0%, chemical oxygen demand (COD (84.6%, 77.7%, total suspended solids(TSS (94.8%,89.9%,total nitrogen(TN(79.5%,66.0%,ammonium nitrogen(NH4+-N(98.8%, 86.6% and total phosphorous (TP (83.7%, 82.8%. Average abatement efficiency for nitrate nitrogen (NO3−-N (−1280.5%, −961.1% and nitrite nitrogen (NO2−-N (−5.8%, −40.0% were negative because its content in influent wastewater was very low and they appear mainly from influent NH4+-N, as a result of purification processes carried out in the HF-CW bed. The abatement rates make the system suitable to produce discharges into the environment in accordance with Spanish law. It is noteworthy that the HF-CW patch suffered an episode of bed drying during the summer of 2013, whereby the causes were related to system oversizing and high evapotranspiration in the area. As a consequence, the decrease in the abatement of water pollutants during the second year can be attributed to the creation of preferential water flow paths and short circuits through the constructed wetland (CW bed. As a result of the oversizing of the CW, a theoretical resizing based on BOD5, TSS, TN or TP is proposed. The calculated values for the redesign were: 5.22 m2 considering DBO5, 0.18 m2 considering TSS, 10.14 m2 considering
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Directory of Open Access Journals (Sweden)
Luiz Sérgio Silva
2007-12-01
Full Text Available A reestruturação produtiva no setor financeiro brasileiro instalou-se por meio do trinômio demissões em massa, automação e terceirização, além de processos de reengenharia empresarial, com redução de níveis hierárquicos, flexibilização e polivalência de funções. O bancário, para se adaptar e resistir às exigências, aumentou seu nível de escolaridade, tornou-se polivalente e exímio vendedor, submetendo-se à precariedade das condições de trabalho, aumento da carga de serviços, longas jornadas e baixos salários. Este trabalho teve como objetivo avaliar o processo de reestruturação produtiva em um banco público do Estado de Minas Gerais, Brasil, e seus possíveis impactos na saúde de seus trabalhadores. Analisou-se também o absenteísmo no período entre 1998 e 2003, quando houve maior desenvolvimento de doenças, como lesão por esforço repetitivo/distúrbios osteomusculares relacionados ao trabalho (LER/DORT e os distúrbios mentais e comportamentais, sendo responsáveis, respectivamente, por 56% e 19% do número de dias de afastamentos. O processo continuou até os dias atuais, com uma política restritiva de contratações. Novos estudos se fazem necessários para a continuidade desta análise e para confirmar os resultados encontrados.Restructuring of the Brazilian financial sector was consolidated through the combination of mass lay-offs, automation, and outsourcing, in addition to business reengineering with leveling of hierarchical echelons, labor casualization, and multi-function jobs. In order to comply and deal with the new demands, bank employees had to increase their schooling, become multi-functional and expert sales attendants, and submit to substandard conditions in the workplace, increased workload, overtime, and low wages. The purpose of the current study was to examine the restructuring process in a state-owned bank in Minas Gerais State, Brazil, and its impacts on workers' health. The study also
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Satchithanantham, Sanjayan; Wilson, Henry F.; Glenn, Aaron J.
2017-06-01
Consumptive use of shallow groundwater by phreatophytic vegetation is a significant part of the water budget in many regions, particularly in riparian areas. The influence of vegetation type on groundwater level fluctuations and evapotranspiration has rarely been quantified for contrasting plant communities concurrently although it has implications for downstream water yield and quality. Hourly groundwater evapotranspiration (ETG) rates were estimated for grass and tree riparian vegetation in southwestern Manitoba, Canada using two modified White methods. Groundwater table depth was monitored in four 21 m transects of five 3 m deep monitoring wells in the riparian zone of a stream reach including tree (Acer negundo; boxelder) and grass (Bromus inermis; smooth brome) dominated segments. The average depths to the groundwater table from the surface were 1.4 m and 1 m for the tree and grass segments, respectively, over the two-year study. During rain free periods of the growing season ETG was estimated for a total of 70 days in 2014 and 79 days in 2015 when diurnal fluctuations were present in groundwater level. Diurnal groundwater level fluctuations were observed during dry periods under both segments, however, ETG was significantly higher (p < 0.001) under trees compared to grass cover in 2014 (a wet year with 72% higher than normal growing season precipitation) and 2015 (a drier year with 15% higher than normal growing season precipitation). The two methods used to estimate ETG produced similar daily and seasonal values for the two segments. In 2014, total ETG was approximately 50% (148 mm) and 100% (282-285 mm) of reference evapotranspiration (ETref, 281 mm) for the grass and tree segments, respectively. In 2015, total ETG was approximately 40% (106-127 mm) and 120% (369-374 mm) of ETref (307 mm) for the grass and tree segments, respectively. Results from the study show the tree dominated portions of the stream reach consumed approximately 2.4 ML ha-1 yr-1 more
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Expansion of plants with Crassulacean Acid Metabolism under global environment change
Yu, K.; D'Odorico, P.; Collins, S. L.; Carr, D.
2016-12-01
The abundance of plants with Crassulacean Acid Metabolism (CAM) has increased in many drylands worldwide. This is hypothesized to occur because CAM plants store water, take up CO2 at night, exhibit photosynthetic plasticity, and have high water use efficiency. The increased dominance of CAM plants, however, also depends on their competitive relationship with other functional groups, an aspect of CAM plant sensitivity to global environmental change that has remained largely understudied. Here, we investigated the response of CAM plants and their competitive relationships with C3 and C4 plants under global environmental change. We focused on two pairs of CAM and non-CAM species, namely Cylindropuntia imbricata (a constitutive CAM species) and Bouteloua eriopoda (C4 grass), which co-occur in desert grasslands in northern Mexico, and invasive Mesembryanthemum crystallinum (a facultative CAM species) and Bromus mollis (a C3 invasive grass), which coexist in California's coastal grasslands. A set of growth chamber experiments under altered CO2 and water conditions show that C. imbricata outcompeted B. eriopoda under drought conditions, while in well-watered conditions B. eriopoda was a stronger competitor for soil water than C. imbricata. Under drought conditions a more positive response to CO2 enrichment by C. imbricata indirectly disfavored B. eriopoda, which suggests that interspecific competition can outweigh the favorable direct effect of CO2 enrichment on plant growth. A set of greenhouse experiments under water, N, and soil salinity manipulations showed that drought, N deposition, and/or increased soil salinity served as important drivers for success of M. crystallinum invasion, while B. mollis exerted strong competitive effects on M. crystallinum for light and soil nutrients in well-watered conditions. M. crystallinum switched from C3 photosynthesis to CAM photosynthesis as an adaptive strategy in response to moderate intensity of competition from B. mollis, in
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Assessing the risk of nitrogen deposition to natural resources in the Four Corners area
Reed, Sasha C.; Belnap, Jayne; Floyd-Hanna, Lisa; Crews, Tim; Herring, Jack; Hanna, Dave; Miller, Mark E.; Duniway, Michael C.; Roybal, Carla M.
2013-01-01
the approach utilized here (e.g., we have fertilization plots to explore how N deposition affects Bromus tectorum invasion that will surely yield provoking results), we plan to continue this exciting line of questioning and expect further insight to be forthcoming.
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Fuentes-Ramirez, Andres; Veldman, Joseph W; Holzapfel, Claus; Moloney, Kirk A
2016-10-01
Novel fire regimes are an important cause and consequence of global environmental change that involve interactions among biotic, climatic, and human components of ecosystems. Plant flammability is key to these interactions, yet few studies directly measure flammability or consider how multiple species with different flammabilities interact to produce novel fire regimes. Deserts of the southwestern United States are an ideal system for exploring how novel fire regimes can emerge when fire-promoting species invade ecosystems comprised of species that did not evolve with fire. In these deserts, exotic annual grasses provide fuel continuity across landscapes that did not historically burn. These fires often ignite a keystone desert shrub, the fire-intolerant creosote bush, Larrea tridentata (DC.) Coville. Ignition of Larrea is likely catalyzed by fuels produced by native plants that grow beneath the shrubs. We hypothesize that invasive and native species exhibit distinct flammability characteristics that in combination determine spatial patterns of fire spread and intensity. We measured flammability metrics of Larrea, two invasive grasses, Schismus arabicus and Bromus madritensis, and two native plants, the sub-shrub Ambrosia dumosa and the annual herb Amsinckia menziesii. Results of laboratory experiments show that the grasses carry fire quickly (1.32 cm/s), but burn for short duration (0.5 min) at low temperatures. In contrast, native plants spread fire slowly (0.12 cm/s), but burn up to eight times longer (4 min) and produced hotter fires. Additional experiments on the ignition requirements of Larrea suggest that native plants burn with sufficient temperature and duration to ignite dead Larrea branches (time to ignition, 2 min; temperature at ignition 692°C). Once burning, these dead branches ignite living branches in the upper portions of the shrub. Our study provides support for a conceptual model in which exotic grasses are "spreaders" of fire and native
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Impacts of Climate Variability on Non-native Plant Invasion in the Western U.S.
Bradley, B. A.
2006-12-01
Plant invasions are changing ecosystem structure and function throughout the United States. In many areas of the west, invasive species such as tamarisk (Tamarix spp.), cheatgrass (Bromus tectorum), and yellow starthistle (Centaurea solstitialis) dominate landscapes. Expansion of these species is occurring at a staggering rate, and invasion rates may change in the future as native ecosystems become more or less susceptible to invasion because of changes in climate. For example, evidence suggests that some plant invaders are favored under increased ambient CO2 levels, potentially leading to increased invasion with continued greenhouse gas emissions. In this work, I predict how western invasive plant species may also be affected by changes in climate variability. According to IPCC reports, rising ocean temperatures may change the frequency and intensity of El Niño events, potentially resulting in wetter El Niño years and/or more extreme and lengthier drought. In semi-arid systems, changing frequency or magnitude of extreme weather events may further shift the competitive balance between native and invasive species. For example, cheatgrass and yellow starthistle, both annual invaders, display high inter-annual variability in response to water availability. As a result, plants are larger and produce more seeds than native competitors during extreme wet years. This phenological response is so strong in cheatgrass communities that it can be observed in regional satellite records. Further, dense cheatgrass growth leads to a secondary feedback in the form of wildfire; higher density cheatgrass increases fire frequency in shrublands and enables further cheatgrass colonization. In this work, I synthesize knowledge of invasive plant phenological response under different climate conditions, drawing on information gathered through geographical mapping efforts at state or regional levels by university and agency researchers. Using the ranges of climate tolerance from current
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Sagebrush ecosystems: current status and trends.
Beever, E.A.; Connelly, J.W.; Knick, S.T.; Schroeder, M.A.; Stiver, S. J.
2004-01-01
The sagebrush (Artemisia spp.) biome has changed since settlement by Europeans. The current distribution, composition and dynamics, and disturbance regimes of sagebrush ecosystems have been altered by interactions among disturbance, land use, and invasion of exotic plants. In this chapter, we present the dominant factors that have influenced habitats across the sagebrush biome. Using a large-scale analysis, we identified regional changes and patterns in “natural disturbance”, invasive exotic species, and influences of land use in sagebrush systems. Number of fires and total area burned has increased since 1980 across much of the sagebrush biome. Juniper (Juniperus spp.) and pinyon (Pinus spp.) woodlands have expanded into sagebrush habitats at higher elevations. Cheatgrass (Bromus tectorum), an exotic annual grass, has invaded much of lower elevation, more xeric sagebrush landscapes across the western portion of the biome. Consequently, synergistic feedbacks between habitats and disturbance (natural and human-caused) have altered disturbance regimes, plant community dynamics and contributed to loss of sagebrush habitats and change in plant communities. Habitat conversion to agriculture has occurred in the highly productive regions of the sagebrush biome and influenced up to 56% of the Conservation Assessment area. Similarly, urban areas, and road, railroad, and powerline networks fragment habitats, facilitate predator movements, and provide corridors for spread of exotic species across the entire sagebrush biome. Livestock grazing has altered sagebrush habitats; the effects of overgrazing combined with drought on plant communities in the late 1880s and early 1900s still influences current habitats. Management of livestock grazing has influenced sagebrush ecosystems by habitat treatments to increase forage and reduce sagebrush and other plant species unpalatable to livestock. Fences, roads, and water developments to manage livestock movements have further
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Geomorphic and land cover identification of dust sources in the eastern Great Basin of Utah, U.S.A.
Hahnenberger, Maura; Nicoll, Kathleen
2014-01-01
This study identifies anthropogenically disturbed areas and barren playa surfaces as the two primary dust source types that repeatedly contribute to dust storm events in the eastern Great Basin of western Utah, U.S.A. This semi-arid desert region is an important contributor to dust production in North America, with this study being the first to specifically identify and characterize regional dust sources. From 2004 to 2010, a total of 51 dust event days (DEDs) affected the air quality in Salt Lake City, UT. MODIS satellite imagery during 16 of these DEDs was analyzed to identify dust plumes, and assess the characteristics of dust source areas. A total of 168 plumes were identified, and showed mobilization of dust from Quaternary deposits located within the Bonneville Basin. This analysis identifies 4 major and 5 secondary source areas for dust in this region, which produce dust primarily during the spring and fall months and during moderate or greater drought conditions, with a Palmer Drought Index (PDI) of - 2 or less. The largest number of observed dust plumes (~ 60% of all plumes) originated from playas (ephemeral lakes) and are classified as barren land cover with a silty clay soil sediment surface. Playa surfaces in this region undergo numerous recurrent anthropogenic disturbances, including military operations and anthropogenic water withdrawal. Anthropogenic disturbance is necessary to produce dust from the vegetated landscape in the eastern Great Basin, as evidenced by the new dust source active from 2008 to 2010 in the area burned by the 2007 Milford Flat Fire; this fire was the largest in Utah's history due to extensive cover of invasive cheatgrass (Bromus tectorum) along with drought conditions. However, dust mobilization from the Milford Flat Burned Area was limited to regions that had been significantly disturbed by post-fire land management techniques that consisted of seeding, followed by chaining or tilling of the soil. Dust storms in the eastern
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Bockstette, S.; Landhäusser, S.; Pinno, B.; Dyck, M. F.
2014-12-01
Reclaimed soils are typically characterized by increased bulk densities, penetration resistances and poor soil structure as well as associated problems with hydrology and aeration. As a result, available rooting space for planted tree seedlings is often restricted to a shallow layer of topsoil, which is usually of higher quality and is cultivated prior to planting. This may hinder the development of healthy root systems, thus drastically increasing the risk for plant stress by limiting access to soil resources such as water, nutrients and oxygen. These problems are exacerbated when herbaceous plants compete for the same resources within this limited root-zone. To understand how limited rooting space affects the physiology of young trees, we experimentally manipulated soil conditions and levels of competition at a reclaimed mine site in central Alberta, Canada. The site was characterized by heavily compacted, fine textured subsoil (~2.0 Mg ha-1), capped with 15 cm of topsoil (~1.5 Mg ha-1). In a replicated study (n=6) half the plots were treated with a subsoil plow to a depth of about 60 cm to increase available rooting spece. Subsequently, trembling aspen (Populus tremuloides Michx.) and smooth brome (Bromus inermis L.) were planted to create four vegetation covers: aspen (a), brome (b), aspen + brome (ab) and control (c) (no vegetation). Various soil properties, including texture, bulk density, penetration resistance and water availability, in conjunction with plant parameters such as root and shoot growth, leaf area development, sap flow, and stomatal conductance have since been monitored, both in-situ and through destructive sampling. Our results indicate that the soil treatment was effective in lowering bulk densities and penetration resistance, while improving moisture retention characteristics. Tree seedling growth and leaf area development were significantly greater without competition, but did not differ between soil treatments. The soil treatment generally
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Energy Technology Data Exchange (ETDEWEB)
Yavnyuk, A. [National Aviation University, Kiev (Ukraine); Shevtsova, N.; Gudkov, D. [Institute of Hydrobiology of the National Academy of Sciences, Kiev (Ukraine)
2014-07-01
Environmental protection requires effective monitoring system of radionuclide contamination and radiobiological effects as well as development of their prevention and minimizing measures for humans and biota. There is a majority of conventional techniques for living organisms' habitat quality assessment. One of the most widespread, convenient and accessible ones, is the seed progeny analysis, for example of conifers, cereals and wild herbaceous plants. Availability of vitality, growth, mutability indexes and abnormalities of vascular plant germs for environment quality express assessment was discussed in numerous publications. However, this point is studied insufficiently concerning aquatic vascular plants, forming communities playing significant role in radionuclides distribution in contaminated water bodies. Common reed (Phragmites australis (Trin) Ex. Steud) is a widespread species mostly dominating in air-aquatic vascular plant communities of freshwater bodies; it is a first-order {sup 137}Cs and {sup 90}Sr accumulating species. To assess the common reed germs growth indexes availability, seeds were sampled in polygon water bodies of different radionuclide contamination levels and 0.7-22 mcGy h{sup -1} total absorbed dose range, within the Chernobyl Exclusion Zone. In water bodies with background level of radionuclide contamination, for comparison, total absorbed dose varied in range of 0.03-0.3 mcGy h{sup -1}. Series of seeds germination experiments was carried out in laboratory conditions. Complex of germs indexes was investigated, conditionally divided into three groups: (1) Vitality indexes. In course of experiment series, vitality was assessed via germinating energy, germinating ability indexes, germination period (first and last germ appearance) and survivability study; (2) Growth indexes. Root and leaf length, occurrence of plant groups with different vegetative organs length were determined for germs growth speed assessment; (3) Teratological
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Directory of Open Access Journals (Sweden)
Frank Michael Carlos Kuehn
2012-12-01
Full Text Available Notam-se nas ciências humanas enormes dificuldades na definição e no emprego dos conceitos que designam fenômenos culturais. Isso vale também para a área da música, onde costuma se notar certa confusão quando se passa para o entendimento do que designam os termos interpretação e performance. O presente ensaio quer responder a essa tarefa, urgente tanto do ponto de vista teórico quanto científico. Como a análise envolve a tradução e a transliteração de conceitos fundamentais de um idioma para outro, abordam-se primeiramente os critérios que norteiam a sua aplicação no contexto histórico da tradição musical clássico-romântica vienense. O objetivo central é demonstrar como esses conceitos diferem em sentido e fim. O próximo passo consiste numa análise criteriosa do conceito de reprodução musical. Por fim, propõe-se o trinômio reprodução musical, interpretação e performance como arcabouço conceitual para o ensino e a pesquisa da(s prática(s interpretativa(s. Ao mesmo tempo, o campo teórico da disciplina aumenta em sua abrangência migrando de uma noção embasada quase que unicamente na interpretação para a de um processo artístico multiforme de grande potencial produtivo e transformador que inclui também os elementos extramusicais da reprodução.Great difficulties are noted in human sciences regarding the definition and use of the concepts designating cultural phenomena. This also stands good for the musical area, in which not often arise certain confusion when one moves to the understanding of what the terms interpretation and performance designate. The present essay aims to answer to this task, urgent both from the theoretical and from the scientific viewpoints. As the analysis involves the translation and transliteration of fundamental concepts from one idiom to another, we first approach the criteria guiding their application within the historical context of the classical-romantic Viennese musical
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Esra GÜRSOY
2017-06-01
Full Text Available This study was carried out to determine the mineral substances such as macro and micro minerals of legume and cereal forages grown as naturally in the pastures of Erzurum province. In present study, clover, (Medicago sativa, mountain hispanic sainfoin (Hedysarum elegans, bird vetch (Vicia cracca, hairy vetch (Vicia villosa, mountain vetch (Vicia alpestris, mountain clover (Trifolium montanum, caucasian clover (Trifolium ambiguum, the three-headed clover (Trifolium trichocephalum, tawny grass crown (Coronilla varia, the crown of the eastern horn of grass (Coronilla orientatis and yellow flowers gazelle (Lotus corniculatus from legume forages; cocksfoot (Dactylis glomerata, crested wheatgrass (Agropyron cristatum, red fescue (Festuca rubra, sheep ball (Festuca ovina, tawny bromine (Bromus variegatus, blue split (Agropyron intermedium, kelp tail grass (Phleum pratense, meadow bluegrass (Poa pratensis from cereal forages were investigated. The obtained data were subjected to an analysis of variance by using SPSS 12.0 package program. Significant differences between means were tested by using Duncan’s Multiple Range Test. Macro minerals such as Nitrogen (N, Phosphorus (P, Potassium (K, Calcium (Ca, Magnesium (Mg and Sulfur (S assigned for legume forages changed between 2.39- 3.30%, 1.16-1.28%, 0.70-2.69%, 0.56-1.61%, 0.11-0.51% and 0.16-0.27%, respectively. The amounts of micro mineral like Iron (Fe, Virgin (Cu, Zinc (Zn, Manganese (Mn and Boron (B of legume forages were determined to be 105.9-893.7 ppm, 2.22-12.36 ppm, 14.11-195 ppm, 18.18-66.58 ppm and 5.91-40.39 ppm, respectively. Instances of macro minerals of cereal forages were found for N 1.76-of 2.19%, P 1.10-1.19%, K 1.99-3.25%, Ca 0.09-1.15%, Mg 0.07-0.26% and S 0.22-0.36% in present study. Micro minerals such as Fe, Cu, Zn, Mn and B determined for cereal forages changed between 74.90-630.6 ppm, 4-9.84 ppm, 31.49-335.6 ppm, 24.63-94.51 ppm and 0.35-26.64 ppm, respectively. In conclusion
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Effectiveness of post-fire seeding at the Fitzner-Eberhardt Arid Land Ecology Reserve, Washington
Wirth, Troy A.; Pyke, David A.
2011-01-01
In August 2007, the Milepost 17 and Wautoma fires burned a combined total of 77,349 acres (31,302 hectares) of the Fitzner-Eberhardt Arid Land Ecology Reserve (ALE), part of the Hanford Reach National Monument administered by the U.S. Fish and Wildlife Service (USFWS) Mid-Columbia National Wildlife Refuge. In 2009, the USFWS implemented a series of seeding and herbicide treatments to mitigate potential negative consequences of these fires, including mortality of native vegetation, invasion of Bromus tectorum (cheatgrass), and soil erosion. Treatments included combinations of seeding (drill and aerial), herbicides, and one of six different mixtures of species. Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) also was planted by hand in a small area in the southern end of the fire perimeter. Due to differences in plant communities prior to the fire and the multiple treatments applied, treatments were grouped into five treatment associations including mid-elevation aerial seedings, low-elevation aerial seedings, low-elevation drill seedings, high-elevation drill seeding, and no seeding treatments. Data collected at the mid-elevation aerial seedings indicate that the seeding did not appear to increase the density of seedlings compared to the non-seeded area in 2010. At the low-elevation aerial seedings, there were significantly more seedlings at seeded areas as compared to non-seeded areas. Low densities of existing perennial plants probably fostered a low-competition environment enabling seeds to germinate and emerge in 2010 during adequate moisture. Low-elevation drill seedings resulted in significant emergence of seeded grasses in 2009 and 2010 and forbs in 2010. This was likely due to adequate precipitation and that the drill seeding assured soil-to-seed contact. At the high-elevation drill seeding, which was implemented in 2009, there were a high number of seedlings in 2010. Transplanting of A. tridentata following the fires resulted in variable
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Sýkorová, Zuzana; Ineichen, Kurt; Wiemken, Andres; Redecker, Dirk
2007-12-01
The community composition of arbuscular mycorrhizal fungi (AMF) was investigated in roots of four different plant species (Inula salicina, Medicago sativa, Origanum vulgare, and Bromus erectus) sampled in (1) a plant species-rich calcareous grassland, (2) a bait plant bioassay conducted directly in that grassland, and (3) a greenhouse trap experiment using soil and a transplanted whole plant from that grassland as inoculum. Roots were analyzed by AMF-specific nested polymerase chain reaction, restriction fragment length polymorphism screening, and sequence analyses of rDNA small subunit and internal transcribed spacer regions. The AMF sequences were analyzed phylogenetically and used to define monophyletic phylotypes. Overall, 16 phylotypes from several lineages of AMF were detected. The community composition was strongly influenced by the experimental approach, with additional influence of cultivation duration, substrate, and host plant species in some experiments. Some fungal phylotypes, e.g., GLOM-A3 (Glomus mosseae) and several members of Glomus group B, appeared predominantly in the greenhouse experiment or in bait plants. Thus, these phylotypes can be considered r strategists, rapidly colonizing uncolonized ruderal habitats in early successional stages of the fungal community. In the greenhouse experiment, for instance, G. mosseae was abundant after 3 months, but could not be detected anymore after 10 months. In contrast, other phylotypes as GLOM-A17 (G. badium) and GLOM-A16 were detected almost exclusively in roots sampled from plants naturally growing in the grassland or from bait plants exposed in the field, indicating that they preferentially occur in late successional stages of fungal communities and thus represent the K strategy. The only phylotype found with high frequency in all three experimental approaches was GLOM A-1 (G. intraradices), which is known to be a generalist. These results indicate that, in greenhouse trap experiments, it is difficult
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Becerra, C.; Schimel, J.
2013-12-01
Soil is the largest reservoir of organic carbon in terrestrial ecosystems and as such, represents a potential sink for carbon dioxide.The decomposition products of dead roots buried in the soil is a contributor to soil organic carbon. However, changing precipitation patterns may affect its fate by influencing the microbial community responsible for decomposing dead roots. To assess the impact of changing precipitation patterns, we constructed microcosms with grassland soil collected from the UCSB Sedgwick Reserve, an active and long-term research site, and dead roots from greenhouse-grown grass, Bromus diandrus. Microcosms were wetted continuously, every seven days, or every twenty days. Sets of microcosms were periodically deconstructed to assess the soil versus the roots-associated microbial community and its function. Differences in respiration rates of microcosms continuously wetted or wetted every 7 days versus microcosms wetted every 20 days existed for the first 70 days. After which, no differences in respiration rates were seen with microcosms containing roots and the no roots control. Relatedly, after a 70% roots mass loss by day 50, there was no difference in the respiration rate of microcosms containing roots and the no roots control. More than half of the roots mass loss had occurred by 30 days. By the end of the incubation period, the roots mass loss in continuously wet and 7-day wetted microcosms were over 80% compared to 67% for the microcosms wetted every 20 days. Microbial biomass in the soil were constant over time and showed no difference in treatment except with the no roots control during the first half of the incubation period. Hydrolytic enzyme activities (β-1,4-glucosidase; α-1,4-glucosidase; β-1,4-xylosidase; β-1,4-cellobiosidase) on the roots versus the soil attached to the roots were over an order greater and decreased faster with the exception of N-acetyl-glucosaminidase and acid phosphatase. Oxidative enzyme activities (phenol
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Impact of different soil cultivation on weed species in winter rape (oilseed
Directory of Open Access Journals (Sweden)
Jan Winkler
2005-01-01
Full Text Available A community of weeds and crops is affected by a number of factors, including, among other things, also tillage. In the years 2000–2002, the composition of weed species in rape stands was evaluated on the fields with the total area of 551 hectares (1 hectar equals to some 2.47 acres. The evaluation was carried out with the application of methodology developed by Kühn (1982. On the fields located in the cadastral area of Olomouc – Holice, which had been cultivated in a traditional manner, 115 relevés were recorded. On the fields in the cadastral area of Bohuňovice, which had been cultivated with the application of reduced tillage, 97 relevés were recorded and evaluated. All of the above fields were subjected to the application of chemical agents reducing the occurrence of weeds. The data thus received were processed by means of multidimensional analysis of ecological data with the application of a RDA method (Redundancy Analysis. In the course of three years, 75 weed species were found on the fields under conventional tillage, on the average, 8.2 species per a relevé, while 66 weed species were found during the same period of time on the fields cultivated by means of reduced tillage, on the average, 8.6 species per a relevé. The application of RDA analysis enabled us to sort out the selected species of weeds (i.e. those the frequency of occurrence of which exceeded 15 % into three groups. The conditions provided by the conventional tillage appeared to be more satisfactory for the weed species included in the first group (Arctium tomentosum, Elytrigia repens, Helianthus tuberosus, Chenopodium album, Lolium perenne and Papaver rhoeas. The species included in the second group, i.e. Alsinula media, Apera spica-venti, Atriplex patula, Bromus sterilis, Capsella bursa-pastoris, Equisetum arvense, Fallopia convolvulus, Myosotis arvensis and Thlaspi arvense., responded to reduced tillage by the increase in cover or by increased frequency of
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Directory of Open Access Journals (Sweden)
Popiela Agnieszka
2015-03-01
-natural and natural habitats is two times lower, while that of holoagriophytes and hemiagriophytes is 56.3% and 43.7%, respectively. It seems that in the case of some invasive and potentially invasive species, a decrease in the number of their locations may be observed from the west to the east (e.g. for Acer negundo, Bromus carinatus, Clematis vitalba, Helianthus tuberosus, Lycium barbarum, Reynoutria japonica, Rosa rugosa, Vicia grandiflora. Distribution patterns for some species (e.g. for Parthenocytisus inserta or Xanthium albinum are indicative of a likely major role of the Odra River valley in the spreading of invasive species. It should be kept in mind that the area of the North-West Poland is poorly examined in terms of its flora, so the results provided in this paper are tentative. Nevertheless, the maps illustrate colonisation trends and directions and, moreover, have been so far the only attempt to synthesise this problem in NW Poland.
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Knežević Aleksa
2012-01-01
Full Text Available A total of 205 taxa and stands of 12 plant communities were found to comprise the plant cover of the permanent grassland on the solonetz and solonchakic solonetz soils located in the vicinity of the town of Novi Kneževac (Vojvodina Province, Serbia. The registered taxa included 177 plant species, six subspecies, eight varieties, 13 forms and one lusus. The ecological analysis of the flora involved 191 taxa. That group consisted of 177 species, six subspecies, three varieties and five forms. The three varieties, Aster tripolium L. var. pannonicus ( Jacq. Beck, Chenopodium rubrum L. subsp. botryoides Sm. var. crassifolium (Hornem Kov. and Sonchus arvensis L. var. uliginosus (M.B. Grec. were used for analysis because their higher taxonomic categories were not recorded in the studied flora. The five forms, Aster sedifolius L. f. subsquamosus Soy, Bromus commutatus Schrad. f. violaceus Podp., Mentha aquatica L. f. erromera Top., Poa bulbosa L. f. vivipara Koel. and Scleranthus annus L. f. minimus Schur., were used for the same reason. The ecological analysis encompassed stands of all 12 recorded communities, i.e. ass. Scirpo-Phragmitetum W. Koch 1926, ass. Bolboschoenetum maritimi continentale Soy (1927 1957, ass. Acorelletum pannonici Soy (1939 1947, ass. Puccinelletum limosae (Rapcs. 1927 Soy 1930, ass. Pholiuro-Plantaginetum tenuiflorae (Rapcs. 1927 Wendel. 1943, ass. Hordeetum histricis (Soy 1933 Wendel. 1943, ass. Camphorosmetum annuae (Rapcs. 1916 Soy 1933 corr. Soy 1938, ass. Agrostio-Alopecuretum pratensis Soy (1933 1947, ass. Agrostio-Eleochariti-Alopecuretu geniculati (Magyar1928 Soy (1939 1947, ass. Artemisio-Festucetum pseudovinae (Magyar 1928 Soy 1945, ass. Achilleo-Festucetum pseudovinae (Magyar 1928 Soy 1945 and ass. Festuco-Andropogonetum ischaemi Vučk. 1985. The ecological analysis of the plant cover indicated that halophytes made 30.37% of the flora of the permanent grassland near the town of Novi Kneževac, and that the stands of
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International Nuclear Information System (INIS)
Tuleubaev, B.A.; Baiganov, A.T.; Seisebaev, A.T.; Nesipbaev, Sh.T.; Dzhanin, B.T.; Sultanova, B.M.
1998-01-01
-forming species of the Degelen Mountains. The results of work on fauna analysis show that 86 species of vertebrates live on the territory studied, including 2 species of amphibian, 6 species of reptiles, 59 species of birds, 19 species of mammals. Four species of all the found are rare species included in the Red Book of Kazakstan. Works on recovery of vegetation cover in the areas of tunnel demilitarization where the vegetative cover had been completely destroyed have been started. The experimental areas near four tunnels have been sown with seedling of poplar, weeping birch, Tatar maple, and elm; the experimental areas have been sown with perennial species of grass (Bromus inermis, Psothyrostachus, Dactylis glomerata, Lolium Elateus, etc.)
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Rytų baltų CiR tipo veiksmažodžiai
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Dalia Pakalniškienė
2011-12-01
vowel lengthening; moreover, some of the Latvian verbs have parallel ia-stem forms in the dialects. All express active action, cf. Lith. trìna – trýnė : Latvian trinu // trin̦u – trinu // trînu ‘to sharpen or grind (a blade, to rub or grate’ : OPr. trinie.3.2. Two of the a-stem verbs have qualitative vowel gradation (there are more vestigial apophonic paradigms in the dialects: Lith. vérda // vìra // vera – vìrė : Latv. vę̂rd – vira, Lith. gẽna – gìnė : Latv. dzęnu – dzinu. These several archaic paradigms are at the early stage, from which new structural models began to develop in the Eastern Baltic languages. The dialect present tense base forms of the Eastern Baltic languages demonstrate that this type was much more plentiful previously, cf. Lith. dẽla – dìlo, Latv. dęl; Lith. svẽla; Latv. svęl; Lith. gẽma, Latv. dzęmu. These bear witness to former paradigms with qualitative vowel gradation; later in both of the Baltic languages the vocalism was generalized for the entire paradigm. Multiple lines of development can be seen: 1 most frequently the appearance of binary oppositions: Lith. kẽlia / kỹla // kìlsta : Latv. ceļu / cilstu – diathetic opposition with differentiated categorial semantics, morphological structure and vocalism; 2 more rarely ternary oppositions develop: Lith. skẽlia I skìlia / skỹla : Latv. šķeļu / šķiļu; 3 zero-grade roots are generalized and acquire either a, ia-stem or infix or sta-stem structure, depending on the categorial semantics (and the root-final sonant, cf. Lith. trìna – trýnė : Latv. trinu // trin̦u – trinu // trînu ‘to sharpen or grind (a blade, to rub or grate’; Lith. gìria – gýrė : Latv. dzir̦u – dzĩru or Lith. gìmsta – gìmė, Latv. dzìmstu – dzimu. Thus new structural models of the Eastern Baltic verbs developed.Evolution, origin.1. The processes discussed should be considered an Eastern Baltic innovation, because the Old
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U.S. Geological Survey Science for the Wyoming Landscape Conservation Initiative-2010 Annual Report
Bowen, Zachary H.; Aldridge, Cameron L.; Anderson, Patrick J.; Assal, Timothy J.; Biewick, Laura; Blecker, Steven W.; Boughton, Gregory K.; Bristol, R. Sky; Carr, Natasha B.; Chalfoun, Anna D.; Chong, Geneva W.; Clark, Melanie L.; Diffendorfer, Jay E.; Fedy, Bradley C.; Foster, Katharine; Garman, Steven L.; Germaine, Stephen S.; Holloway, JoAnn; Homer, Collin G.; Kauffman, Matthew J.; Keinath, Douglas; Latysh, Natalie; Manier, Daniel J.; McDougal, Robert R.; Melcher, Cynthia P.; Miller, Kirk A.; Montag, Jessica; Potter, Christopher J.; Schell, Spencer; Shafer, Sarah L.; Smith, David B.; Stillings, Lisa L.; Tuttle, Michele L.W.; Wilson, Anna B.
2011-01-01
the Moxa Arch Natural Gas Development area) and (2) the study of cheatgrass (Bromus tectorum) occurrence in burn treatments of the Little Mountain Ecosystem. The activity that entails evaluating relationships between ungulate herbivory and fire on aspen (Populus tremuloides) recruitment also was expanded to include relationships between stand characteristics of and herbivory on aspen in various ecohydrological settings. The USGS continued compiling data and developing geospatial products from all of its WLCI activities to support (1) ranking and prioritizing of proposed conservation projects, (2) developing the WLCI Integrated Assessment, and (3) developing the WLCI 5-year Conservation Action Plan. Two activities were completed in FY2010: (1) the conceptual modeling and indicator selection for monitoring resource conditions across the WLCI region, and (2) the literature review on effects of oil and gas development in western regions of the United States, both of which are in the last stages of publication.
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S. O. Belyakov
2017-01-01
Full Text Available This article discusses modelling of Aboveground Net Primary Production (ANPP of steppe (arid grassland ecosystems plant species in relation to changes in total precipitation over the previous year at the “Stara” study site, Biosphere Reserve “Askania-Nova”, Khersonregion (Ukraine. To investigate linkages between precipitation and Aboveground Net Primary Production, correlation analysis was chosen and a time series regression analysis was based on the data set for the period 1988–2012. The NPP dependence on quantity of precipitation was found to be more significant for the previous autumn-winter-spring period (AWSP than for the previous 12 month period. A regression model of ANPP’s dependence on AWSP is proposed. This model was further validated by the authors’ samples of ANPP, collected at the “Stara” study site in 2013–2016. The regression model showed a non-linear (quadratic dependence of net primary production of zonal and intrazonal plant coenoses and total precipitation for the autumn-winter-spring period for arid grasslands with a coefficient of determination equal to 0.54 and significance level less than 0.05. The non-linear equation for these relations, visualized by a parabola curve, was calculated using the Nonlinear Least-Squares Regression Method. The data set, based on calculated predicted values, using the calculated equation, had a similar dynamic to the historical data on ANPP, but the model could not predict critical values. For this reason, additional studies are required for critical precipitation events. Non-linear response, investigated according to regression analysis, reveals optimal zones of plant growth, depending on the total precipitation level before the vegetation peak. For research areas where the dominant species are the turf grasses Stipa ucrainica P. Smirn., S. capillata L., S. lessingiana Trin. & Rupr., Festuca valesiaca Gaudin, Koeleria cristata (L. Pers. the optimal precipitation rates
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An In-Situ Root-Imaging System in the Context of Surface Detection of CO2
Apple, M. E.; Prince, J. B.; Bradley, A. R.; Zhou, X.; Lakkaraju, V. R.; Male, E. J.; Pickles, W.; Thordsen, J. J.; Dobeck, L.; Cunningham, A.; Spangler, L.
2009-12-01
Carbon sequestration is a valuable method of spatially confining CO2 belowground. The Zero Emissions Research Technology, (ZERT), site is an experimental facility in a former agricultural field on the Montana State University campus in Bozeman, Montana, where CO2 was experimentally released at a rate of 200kg/day in 2009 into a 100 meter underground injection well running parallel to the ground surface. This injection well, or pipe, has deliberate leaks at intervals, and CO2 travels from these leaks upward to the surface of the ground. The ZERT site is a model system designed with the purpose of testing methods of surface detection of CO2. One important aspect of surface detection is the determination of the effects of CO2 on the above and belowground portions of plants growing above sequestration fields. At ZERT, these plants consist of a pre-existing mixture of herbaceous species present at the agricultural field. Species growing at the ZERT site include several grasses, Dactylis glomerata (Orchard Grass), Poa pratensis (Kentucky Bluegrass), and Bromus japonicus (Japanese Brome); the nitrogen-fixing legumes Medicago sativa, (Alfalfa), and Lotus corniculatus, (Birdsfoot trefoil); and an abundance of Taraxacum officinale, (Dandelion). Although the aboveground parts of the plants at high CO2 are stressed, as indicated by changes in hyperspectral plant signatures, leaf fluorescence and leaf chlorophyll content, we are interested in determining whether the roots are also stressed. To do so, we are combining measurements of soil conductivity and soil moisture with root imaging. We are using an in-situ root-imaging system manufactured by CID, Inc. (Camas, WA), along with image analysis software (Image-J) to analyze morphometric parameters in the images and to determine what effects, if any, the presence of leaking and subsequently upwelling CO2 has on the phenology of root growth, growth and turnover of individual fine and coarse roots, branching patterns, and root
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The California Valley grassland
Keeley, J.E.; Schoenherr, Allan A.
1990-01-01
Grasslands are distributed throughout California from Oregon to Baja California Norte and from the coast to the desert (Brown 1982) (Figure 1). This review will focus on the dominant formation in cismontane California, a community referred to as Valley Grassland (Munz 1959). Today, Valley Grassland is dominated by non-native annual grasses in genera such as Avena (wild oat), Bromus (brome grass), and Hordeum (barley), and is often referred to as the California annual grassland. On localized sites, native perennial bunchgrasses such as Stipa pultra (purple needle grass) may dominate and such sites are interpreted to be remnants of the pristine valley grassland. In northwestern California a floristically distinct formation of the Valley Grassland, known as Coast Prairie (Munz 1959) or Northern Coastal Grassland (Holland and Keil 1989) is recognized. The dominant grasses include many native perennial bunchgrasses in genera such as Agrostis, Calamagrostis, Danthonia, Deschampsia, Festuca, Koeleria and Poa (Heady et al. 1977). Non-native annuals do not dominate, but on some sites non-native perennials like Anthoxanthum odoratum may colonize the native grassland (Foin and Hektner 1986). Elevationally, California's grasslands extend from sea level to at leas 1500 m. The upper boundary is vague because montane grassland formations are commonly referred to as meadows; a community which Munz (1959) does not recognize. Holland and Keil (1989) describe the montane meadow as an azonal community; that is, a community restricted not so much to a particular climatic zone but rather controlled by substrate characteristics. They consider poor soil-drainage an over-riding factor in the development of montane meadows and, in contrast to grasslands, meadows often remain green through the summer drought. Floristically, meadows are composed of graminoids; Cyperaceae, Juncaceae, and rhizomatous grasses such as Agropyron (wheat grass). Some bunchgrasses, such as Muhlenbergia rigens, are
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Plants as Indicators of Past and Present Zones of Upwelling Soil CO2 at the ZERT Facility
Apple, M. E.; Sharma, B.; Zhou, X.; Shaw, J. A.; Dobeck, L.; Cunnningham, A.; Spangler, L.; ZERT Team
2011-12-01
By their very nature, photosynthetic plants are sensitive and responsive to CO2, which they fix during the Calvin-Benson cycle. Responses of plants to CO2 are valuable tools in the surface detection of upwelling and leaking CO2 from carbon sequestration fields. Plants exposed to upwelling CO2 rapidly exhibit signs of stress such as changes in stomatal conductance, hyperspectral signatures, pigmentation, and viability (Lakkaraju et al. 2010; Male et al. 2010). The Zero Emission Research and Technology (ZERT) site in Bozeman, MT is an experimental facility for surface detection of CO2 where 0.15 ton/day of CO2 was released (7/19- 8/15/2010, and 7/18 - 8/15/2011) from a 100m horizontal injection well, (HIW), 1.5 m underground with deliberate leaks of CO2 at intervals, and from a vertical injector, (VIW), (6/3-6/24/2010). Soil CO2 concentrations reached 16%. Plants at ZERT include Taraxacum officinale (Dandelion), Dactylis glomerata (Orchard Grass), Poa pratensis, (Kentucky Bluegrass), Phleum pratense (Timothy), Bromus japonicus (Japanese Brome), Medicago sativa (Alfalfa) and Cirsium arvense (Canadian Thistle). Dandelion leaves above the zones of upwelling CO2 at the HIW and the VIW changed color from green to reddish-purple (indicative of an increase in anthocyanins) to brown as they senesced within two weeks of CO2 injection. Their increased stomatal conductance along with their extensive surface area combined to make water loss occur quickly following injection of CO2. Xeromorphic grass leaves were not as profoundly affected, although they did exhibit changes in stomatal conductance, accelerated loss of chlorophyll beyond what would normally occur with seasonal senescence, and altered hyperspectral signatures. Within two weeks of CO2 injection at the HIW and the VIW, hot spots formed, which are circular zones of visible leaf senescence that appear at zones of upwelling CO2. The hot spots became more pronounced as the CO2 injection continued, and were detectable
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Healy, R.W.; DeVries, M.P.; Sturrock, Alex M.
1989-01-01
From July 1982 through June 1984, a study was made of the evapotranspiration and microclimate at a low-level radioactive-waste disposal site near Sheffield, Bureau County, Illinois. Vegetation at the site consists of mixed pasture grasses, primarily awnless brome (Bromus inermis) and red clover (Trifoleum pratense). Three methods were used to estimate evapotranspiration: (1) an energy budget with the Bowen ratio, (2) an aerodynamic profile, and (3) a soil-based water budget. For the aerodynamic-profile method, sensible-heat flux was estimated by a profile equation and evapotranspiration was then calculated as the residual in the energy-balance equation. Estimates by the energy-budget and aerodynamic-profile methods were computed from hourly data and then summed by days and months. Yearly estimates (for March through November) by these methods were in close agreement: 648 and 626 millimeters, respectively. Daily estimates reach a maximum of about 6 millimeters. The water-budget method produced only monthly estimates based on weekly or biweekly soil-moisture content measurements. The yearly evapotranspiration estimated by this method (which actually included only the months of April through October) was 655 millimeters. The March-through-November average for the three methods of 657 millimeters was equivalent to 70 percent of total precipitation. Continuous measurements were made of incoming and reflected shortwave radiation, incoming and emitted longwave radiation, net radiation, soil-heat flux, soil temperature, horizontal windspeed, and wet- and dry-bulb air temperature. Windspeed and air temperature were measured at heights of 0.5 and 2.0 meters (and also at 1.0 meter after September 1983). Soilmoisture content of the soil zone was measured with a gamma-attenuation gage. Annual precipitation (938 millimeters) and average temperature (10.8 degrees Celsius) at the Sheffield site were virtually identical to long-term averages from nearby National Weather Service
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Cabezas, Jose Manuel; Gómez, Jose Alfonso; Auxiliadora Soriano, María
2016-04-01
Soil water availability is a major subject in Mediterranean agricultural systems, mainly due to the limited and highly variable annual rainfall, high evaporative demand, and soil hydrological characteristics. The recent expansion of olive cultivation in the rolling-plains of the Guadalquivir valley, due to the higher profitability of new intensive olive orchards, expanded the presence of olive orchards on Vertisols, soils traditionally used for annual rain-fed crops. These soils have a high content of smectitic clays, which give them a high water storage capacity, and are characterized by vertical and deep shrinkage cracks in the dry season, associated to low soil moisture. Farmers make several tillage passes in these olive groves during the summer, in order to cover the cracks and thus reduce soil water loss by evaporation, which will impact especially in rain-fed in the next olive yield. This tillage practice involves removal of plant residues from the soil surface, as well as burying seeds produced by the plants, so this will remain bared at the beginning of the rainy season, when in the Mediterranean climate is frequent occurrence of high-intensity rainfall, which are ideal conditions for soil loss by water erosion, one of the most serious problems for the sustainability of olive cultivation in Andalusia. Although there are some studies showing that water loss by evaporation from deep horizons of a vertic soil might be elevated (eg. Ritchie and Adams, 1974), the presence of plant residues on the soil surface drastically reduced soil water loss (eg Adams et al., 1969). Thus the aim of this study was to assess of soil moisture dynamics in a rain-fed olive orchard growing on a Vertisol under different soil management practices, in Andalusia (southern Spain). Four different soil management treatments were applied, which combined a cover crop (Bromus rubens L.) or bare soil throughout the year by applying herbicides, with tillage in summer to cover the cracks or non
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Paramonova, Tatiana; Komissarova, Olga; Turykin, Leonid; Kuzmenkova, Natalia; Belyaev, Vladimir
2016-04-01
The accident at the Chernobyl nuclear power plant in 1986 had a large-scale action on more than 2.3 million hectares agricultural lands in Russia. The area of radioactively contaminated chernozems of semi-arid steppe zone with initial levels of Cs-137 185-555 kBq/m2 in Tula region received the name "Plavsky radioactive hotspot". Nowadays, after the first half-life period of Cs-137 arable chernozems of the region are still polluted with 3-6-fold excess above the radioactive safety standard (126-228 kBq/m2). Therefore, qualitative and quantitative characteristics of Cs-137 soil-to-plant transfer are currently a central problem for land use on the territory. The purpose of the present study was revealing the biological features of Cs-137 root uptake from contaminated arable chernozems by different agricultural crops. The components of a grass mixture growing at the central part of Plavsky radioactive hotspot with typical dicotyledonous and monocotyledonous plants - galega (Galega orientalis, Fabaceae family) and bromegrass (Bromus inermis, Gramineae family) respectively - were selected for the investigation, that was conducted during the period of harvesting in 2015. An important point was that the other factors influenced on Cs-137 soil-to-plant transfer - the level of soil pollution, soil properties, climatic conditions, vegetative phase, etc. - were equal. So, biological features of Cs-137 root uptake could be estimated the most credible manner. As a whole, general discrimination of Cs-137 root uptake was clearly shown for both agricultural crops. Whereas Cs-137 activity in rhizosphere 30-cm layer of arable chernozem was 371±74 Bq/kg (140±32 kBq/m2), Cs-137 activities in plant biomass were one-two orders of magnitude less, and transfer factor (TF) values (the ratio of the Cs-137 activities in vegetation and in soil) not exceeded 0.11. At the same time bioavailability of Cs-137 for bromegrass was significantly higher than for galega: TFs in total biomass of the
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Rolled lawn as tool for industrial barren remediation
Gorbacheva, T. T.; Ivanova, L. A.; Kikuchi, R.; Gerardo, R.
2009-04-01
term of cultivation (from 1 to 16 July 2008). Rolled lawn was characterized by high plant density 759.0±12.2 units per m2. That parameter achievement is not possible using traditional way of direct seeding in prepared ground that is common in Kola Peninsula region. Mass of 1 m2 rolled lawn is about 5-7 kg. Rolled lawn cost is sufficiently lower than traditional (turf-grounded) one. Grass seeds were choose as more adaptive for severe conditions and suitable for recultivation tasks: Festuca rubra L. - 44.4%, Bromus inermis Leyss. - 33.4%, Festulolium smaragdinum - 11.1%, Festuca pratensis Huds.- 11.1%. Field experiment was carried out in three variants (1- mineral ground - flat site; 2- mineral ground- slope sites; 3- organogenic ground - flat site in depression in five replicates. Growing in very contaminated ground resulted in 50% rolled lawn surface loss but with biodiversity maintenance. Grass roots proliferated in contaminated ground very slowly. It seems obvious that plant roots choose the best zones of soils to grow, and that they avoided toxic zones. More comprehensive results were received for mineral ground due to better natural washing compared to organogenic ground. In all variants we observed secondary roots formation. Simultaneously with rolled lawn placement litterbag experiment was carried out with original vermiculite as filling. Short term (July- September 2008) alteration of nutritional status and contamination level of vermiculite was controlled and compared with quartz as inert material. Observations will continue during 2009-2011 to follow freezing influence and nutrient loss rate.
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Ryan, Barbara J.
1989-01-01
budget. Although monthly totals for each method differed, estimated annual evapotranspiration averages ranged from 630 to 693 millimeters or about 70 percent of precipitation. Tritium concentrations in leaf water from on-site plants were determined for 125 vegetation samples collected during the summers of 1982 through 1986. Concentrations varied significantly among some locations and plant types. Tritium concentrations ranged from the detection limit of 0 .2 to 1,330 nanocuries per liter, with alfalfa (Medicago sativa) having the highest concentrations, followed by brome grass (Bromus inermis), and then red clover (Trifoleum pratense); these variations in concentration are most likely a result of root depth. Runoff and sediment transport were measured from July 1982 through December 1985 in four basins--three comprising almost two-thirds of the 8.1-hectare site and one comprising a 1.4-hectare undisturbed area. Volumes and equivalent weights of collapses were estimated from records of site surficial conditions from October 1978 through December 1985. Runoff showed a direct relation to degree of land modification; lowest mean yields were measured at the undisturbed area, and highest mean yields were measured from the basin composed wholly of trench and intertrench areas. Sediment yield measured onsite averaged 3.4 megagrams per hectare. A total of 315 collapse cavities, corresponding to a cumulative volume of about 500 cubic meters, were documented. Most collapses were recorded after periods of rainfall or snowmelt when soil moisture was near maximum. Almost two-thirds of the collapses, corresponding to 63 percent of the cumulative cavity volume, occurred during February through April. Data for the study of water movement through a trench cover were collected from July 1982 through June 1934. Pressure-head data were collected at four different clusters at depths ranging from 50 to 1,850 millimeters within a selected trench cover. Soil-moisture content f
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Conservation reserve program: benefit for grassland birds in the northern plains
Reynolds, R.E.; Shaffer, T.L.; Sauer, J.R.; Peterjohn, B.G.
1994-01-01
cropland in some counties has been converted primarily to grass. In North Dakota, nearly 3 million acres have been enrolled. Over 90 percent of the CRP plantings in North Dakota are grass and grass-legume mix composed primarily of wheatgrass (Agropyron spp.), smooth brome (Bromus inermis), alfalfa (Medicago saliva) and sweetclover (Melilotus spp.). Mixes of these species have been reported to attract high densities of nesting ducks (Duebbert and Kantrud 1974). According to the CRP provisions, the land must remain idle for the 10-year contract period, with the exception of emergency provisions for haying or grazing. CRP appears to have great potential for benefiting many species of grassland-nesting birds. There have been efforts to document the importance of the CRP to migratory birds in the Upper Great Plains of the U.S. Kantrud (1993) studied duck nest success in CRP cover and concluded that nest success was higher than in planted cover on U.S. Fish and Wildlife Service (FWS) Waterfowl Production Areas (WPAs). Johnson and Schwartz (1993a) measured the use of CRP fields by nonwaterfowl birds and reported that several species have responded positively by colonizing CRP fields. They concluded that CRP has the potential to help reverse the population declines of several species. We investigated the importance of CRP to upland-nesting ducks and certain other grassland-nesting birds. For ducks, we compared nest success in CRP cover with nest success in planted cover on WPAs in the same period (1992-93) and with that of an earlier period (1980-84). For nonwaterfowl, we used BBS data to compare the trends in populations of certain species found in CRP, for the periods 1966-86 (pre-CRP cover establishment) and 1987-92 (post-CRP cover establishment) in North Dakota.
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Directory of Open Access Journals (Sweden)
Pricken de BEM
2013-04-01
Full Text Available RESUMO O Observatório da Saúde no Legislativo (OSL é um espaço virtual (observatorio.fiocruz.br constituído por um banco de dados públicos permanente, sediado na Fundação Oswaldo Cruz - Brasília e destinado ao acompanhamento dos projetos legislativos de interesse à saúde em tramitação no congresso nacional e oferecimento gratuito das informações mais relevantes sobre as proposições legislativas em matéria sanitária. A 54ª Legislatura iniciou-se no ano de 2011 e, desde então, novas proposições foram sendo apresentadas pelo novo corpo político do congresso nacional, renovado com as últimas eleições. O objetivo deste artigo é apresentar resultados de pesquisa realizada na base de dados da Câmara e Senado Federal quanto às proposições legislativas relativas à saúde e acompanhar sua tramitação e evolução no período de 2011 e 2012. No período estudado, constatou-se que cerca de 10% das proposições apresentadas foram relativas à saúde, tendo a maioria delas relação com álcool e drogas. Com o nascimento do observatório, a população ganha o poder fiscalizador e apoiador nas políticas de saúde. Esse projeto visa, também, empoderar o cidadão ao socializar informações acerca do seu direito, possibilitando, assim, o trinômio conhecer – exigir – vivenciar. ABSTRACT The Observatory for Health in the Legislative Power is a virtual space (observatório.friocruz.br built by a permanent public database, based at Fundação Oswaldo Cruz – Brasília/Brazil – and is aimed to follow the ongoing legislative bills addressed to public health in the Brazilian parliament and to offer free relevant information about the legislative propositions on sanitary subject. The 54º Parliamentary Term began on the year of 2011 and new propositions are being presented by the new political body of the national parliament, which was renewed with latest election. The objective of this article is to present results of
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Wirth, Troy A.; Pyke, David A.
2009-01-01
2006 and 0.09 plants/m2 in 2008. Density of seeded perennial grasses at the Double Mountain non-native and native seeding were 2.72 and 3.86 plants/m2 in 2006 and 0.90 and 1.74 plants/m2 in 2008, respectively. The Farewell Bend non-native seeding resulted in 5.62 plants/m2 in 2006 and 0.42 plants/m2 in 2008 while the native seeding had 2.22 seeded grass plants/m2 in 2006 and 0.44 plants/m2 by 2008. The primary reason for low level of establishment on most treatments except the Cow Hollow seeding was most likely the unfavorable timing and amount of precipitation in 2007 and 2008. Measurements of density within the first 3 years provide the best estimate of initial seeding success. Increases in cover due to the seedings were not detectable in the first 3 years following seeding in this monitoring effort. Changes in cover resulting from the treatments may be detectable in cases where the seedings were very successful in the first 3 years following seeding, but in areas with lower annual average precipitation, may not occur consistently. As a result, cover of seeded species may not be a good indication of seeding success in the early years after treatment. However, cover is useful for monitoring initial patterns of abundance of naturally recovering vegetation, exotic annual grasses and forbs, and bare ground. Cover measurements at these four sites revealed patterns common to most of the treatment areas in cover of litter, bare ground, and exotic annuals in response to drill seeding and weather patterns. There was a rapid increase in litter at all treatments after the fire. Additionally, there was less litter in treatment plots than in the control plots in 2006 probably due to the mechanical action of the seed drill. There also was a corresponding decrease in bare ground from 2006 to 2008. Initially, higher bare ground cover at treatment plots appears to be due to the mechanical action of the seed drill. Cover of annual grasses, primarily Bromus tectorum,
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Chemical weed control in Spinach (Spiniacia oleracea
Directory of Open Access Journals (Sweden)
A. Modhej
2016-03-01
(Convolvulus arvensis, Common lambsquarters (Chenopodium album, Malva (Malva spp., Chamomile (Anthemis altissima, Purple nutsedge (Cyperus rotundus, canary grass (Phalaris minor, mouse barley (Hordeum morinum and Japan brome (Bromus japonicus, respectively. The results of variance analysis showed that the effects of treatments on the number of broadleaf and weed narrow leaves were significant. Meteribouzin and Pendimethalin herbicides (pre-emergence, had better control on broadleaf weed than other herbicides. Low amounts of herbicides EPTC (5 lit ha-1 and imazethapyr (0.7 lit ha-1 were the least effective broadleaf weed control. Trifluralin herbicide reduced approximately 44% broadleaf weed density compared to control plots without control. The minimum weight of broadleaf weed at all doses studied allocated to herbicides Pendimethalin and Meteribouzin. Most of reducing the number narrow leaves was belonged to Meteribouzin and Pendimethalin herbicides as pre-emergence with doses of 300 g and 3 lit ha-1, respectively. The effect of treatments on petiole length, number of leaves per plant and the spinach fresh yield was significant in 1% probability level. Meteribouzin damage in spinach was 100%. It was reported that the half-life in soil herbicide Meteribouzin is about 30-60 days. It seems spinach a high sensitivity to the herbicide and relatively long survival in the soil that causing damage spinach was perfect, while maximum weed control amounts in all methods of used allocated to this herbicide. Number of leaves per plant trait was that less affected by weed interference. Both components of leaves per plant (r= 69.0** and petiole length (r= 87.0** showed significant positive correlation with the spinach fresh yield. The highest spinach yield was obtained in Trifluralin herbicide after treatments control. The difference between spinach yield in Trifluralin and control treatments was not significant. Conclusion: In general, the results showed that the broad and narrow leaf
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Directory of Open Access Journals (Sweden)
sahar jannati ataie
2018-02-01
species in canola fields of Gorgan Township and these belonged to 18 families. About 17.1 percent of these species belong to Poaceae and 11.4 percent belongs to Asteraceae and other families, respectively. In general, 77.2 and 22.8 percent of species were annual and perennial weeds, respectively. Also, 80 percent of weeds belong to dicotyledonous and 20 percent to monocotyledonous. The most important species of Poaceae family were Phalaris minor, Avena ludoviciana, Alopecuros sp., Poa annua, Lolium temulentum and Bromus sp. Also, the most important species of Asteraceae were Artemisia annua, Cirsium arvense, Sonchus sp. and Senecio vulgaris. 85.7 percent of weeds reported as broad-leaved weeds and 14.3 percent belong to the narrow leaves. Phalaris minor was the most important weed of narrow leaves and Melilotus officinalis was the most important broad leaf out groups. Among the weeds have been identified, 88.5 percent had photosynthetic cycle of C3 and 11.5 percent were C4. The study results also showed that Phalaris minor had the highest relative dominance among the 35 species and then Melilotus officinalis, Rapistrum rugosum and Avena ludoviciana had 29.4, 28.9 and 23.5 of relative dominance, respectively. To view maps of distribution, based on the abundance of weeds, the three categories 50-100 percent, 30-50 percent and lower than 30 percent were classified. Weeds that have had 50-100 percent frequency were considered as the most important weeds in canola fields of Gorgan. These weeds includes: Phalaris minor and Melilotus officinalis. Weeds that have a frequency between 30-50 percent were considered as medium importance weeds that included Sinapis arvensis, Veronica persica, Avena ludoviciana and Rapistrum rugosum. In final, the weeds with a frequency of less than 30 percent, were placed in the third group as small percentage of surveyed fields. The most important weeds in this group recorded as Artemisia annua, Ranunculus sp., Polygonum convolvulus and Alopecuros sp
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Scott, Michael L; Friedman, Jonathan M.
2018-01-01
This report addresses the relation between flow of the Yampa River and occurrence of herbaceous and woody riparian vegetation in Dinosaur National Monument (DINO) with the goal of informing management decisions related to potential future water development. The Yampa River in DINO flows through diverse valley settings, from the relatively broad restricted meanders of Deerlodge Park to narrower canyons, including debris fan-affected reaches in the upper Yampa Canyon and entrenched meanders in Harding Hole and Laddie Park. Analysis of occurrence of all plant species measured in 1470 quadrats by multiple authors over the last 24 years shows that riparian vegetation along the Yampa River is strongly related to valley setting and geomorphic surfaces, defined here as active channel, active floodplain, inactive floodplain, and upland. Principal Coordinates Ordination arrayed quadrats and species along gradients of overall cover and moisture availability, from upland and inactive floodplain quadrats and associated xeric species like western wheat grass (Pascopyrum smithii), cheatgrass (Bromus tectorum), and saltgrass (Distichlis spicata) to active channel and active floodplain quadrats supporting more mesic species including sandbar willow (Salix exigua), wild licorice (Glycyrrhiza lepidota), and cordgrass (Spartina spp.). Indicator species analysis identified plants strongly correlated with geomorphic surfaces. These species indicate state changes in geomorphic surfaces, such as the conversion of active channel to floodplain during channel narrowing. The dominant woody riparian species along the Yampa River are invasive tamarisk (Tamarix ramosissima), and native Fremont cottonwood (Populus deltoides ssp. wislizenii), box elder (Acer negundo L. var. interius), and sandbar willow (Salix exigua). These species differ in tolerance of drought, salinity, inundation, flood disturbance and shade, and in seed size, timing of seed dispersal and ability to form root sprouts. These
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Directory of Open Access Journals (Sweden)
André Luis Muniz Garcia
2011-12-01
:WordDocument>
O objetivo do presente artigo, pensado preliminarmente como parte integrante de um estudo mais amplo e sistemático sobre o processo de formação do pensamento do jovem Nietzsche, é discutir o estatuto da linguagem em suas considerações sobre estética, notadamente naquela apresentada nos fragmentos, apontamentos e escritos póstumos preparatórios d’O Nascimento da Tragédia. Como se poderá notar, o viés de investigação proposto, respaldado em importantes estudos de literatura secundária, primou por uma esmerada, porém não exaustiva, reconstituição do trinômio: linguagem sonora
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Gannon, Jill J.; Shaffer, Terry L.; Moore, Clinton T.
2013-01-01
Much of the native prairie managed by the U.S. Fish and Wildlife Service (FWS) in the Prairie Pothole Region (PPR) of the northern Great Plains is extensively invaded by the introduced cool-season grasses, smooth brome (Bromus inermis) and Kentucky bluegrass (Poa pratensis). Management to suppress these invasive plants has had poor to inconsistent success. The central challenge to managers is selecting appropriate management actions in the face of biological and environmental uncertainties. In partnership with the FWS, the U.S. Geological Survey (USGS) developed an adaptive decision support framework to assist managers in selecting management actions under uncertainty and maximizing learning from management outcomes. This joint partnership is known as the Native Prairie Adaptive Management (NPAM) initiative. The NPAM decision framework is built around practical constraints faced by FWS refuge managers and includes identification of the management objective and strategies, analysis of uncertainty and construction of competing decision models, monitoring, and mechanisms for model feedback and decision selection. Nineteen FWS field stations, spanning four states of the PPR, have participated in the initiative. These FWS cooperators share a common management objective, available management strategies, and biological uncertainties. Though the scope is broad, the initiative interfaces with individual land managers who provide site-specific information and receive updated decision guidance that incorporates understanding gained from the collective experience of all cooperators. We describe the technical components of this approach, how the components integrate and inform each other, how data feedback from individual cooperators serves to reduce uncertainty across the whole region, and how a successful adaptive management project is coordinated and maintained on a large scale. During an initial scoping workshop, FWS cooperators developed a consensus management objective