Science.gov

Sample records for ambrosia dumosa roots

  1. ARBUSCULAR MYCORRHIZAL COLONIZATION OF LARREA TRIDENTATA AND AMBROSIA DUMOSA ROOTS VARIES WITH PRECIPITATION AND SEASON IN THE MOJAVE DESERT

    SciTech Connect

    M. E. APPLE; C. I. THEE; V. L. SMITH-LONGOZO; C. R. COGAR; C. E. WELLS; R. S. NOWAK

    2004-01-01

    The percentage of fine roots colonized by arbuscular mycorrhizal (AM) fungi varied with season and with species in the co-dominant shrubs Lurreu tridentutu and Ambrosia dumosu at a site adjacent to the Nevada Desert FACE (Free-Air CO{sub 2} Enrichment) Facility (NDFF) in the Mojave Desert. We excavated downward and outward from the shrub bases in both species to collect and examine fine roots (< 1.0 mm diameter) at monthly intervals throughout 2001 and from October 2002 to September 2003. Fungal structures became visible in cleared roots stained with trypan blue. We quantified the percent colonization of roots by AM fungi via the line intercept method. In both years and for both species, colonization was highest in fall, relatively low in spring when root growth began, increased in late spring, and decreased during summer drought periods. Increases in colonization during summer and fall reflect corresponding increases in precipitation. Spring mycorrhizal colonization is low despite peaks in soil water availability and precipitation, indicating that precipitation is not the only factor influencing mycorrhizal colonization. Because the spring decrease in mycorrhizal colonization occurs when these shrubs initiate a major flush of fine root growth, other phenological events such as competing demands for carbon by fine root initiation, early season shoot growth, and flowering may reduce carbon availability to the fungus, and hence decrease colonization. Another possibility is that root growth exceeds the rate of mycorrhizal colonization.

  2. The influence of stream channels on distributions of Larrea tridentata and Ambrosia dumosa in the Mojave Desert, CA, USA: Patterns, mechanisms and effects of stream redistribution

    USGS Publications Warehouse

    Schwinning, S.; Sandquist, D.R.; Miller, D.M.; Bedford, D.R.; Phillips, S.L.; Belnap, J.

    2011-01-01

    Drainage channels are among the most conspicuous surficial features of deserts, but little quantitative analysis of their influence on plant distributions is available. We analysed the effects of desert stream channels ('washes') on Larrea tridentata and Ambrosia dumosa density and cover on an alluvial piedmont in the Mojave Desert, based on a spatial analysis of transect data encompassing a total length of 2775 m surveyed in 5 cm increments. Significant deviations from average transect properties were identified by bootstrapping. Predictably, shrub cover and density were much reduced inside washes, and elevated above average levels adjacent to washes. Average Larrea and Ambrosia cover and density peaked 1??2-1??6 m and 0??5-1??0 m from wash edges, respectively. We compared wash effects in runon-depleted (-R) sections, where washes had been cut off from runon and were presumably inactive, with those in runon-supplemented (+R) sections downslope from railroad culverts to help identify mechanisms responsible for the facilitative effect of washes on adjacent shrubs. Shrub cover and density near washes peaked in both + R and - R sections, suggesting that improved water infiltration and storage alone can cause a facilitative effect on adjacent shrubs. However, washes of < 2 m width in + R sections had larger than average effects on peak cover, suggesting that plants also benefit from occasional resource supplementation. The data suggest that channel networks significantly contribute to structuring plant communities in the Mojave Desert and their disruption has notable effects on geomorphic and ecological processes far beyond the original disturbance sites. ?? 2010 John Wiley & Sons, Ltd.

  3. [Ambrosia pollinosis].

    PubMed

    Déchamp, C

    2013-04-01

    Pollinosis is now called seasonal allergic rhinitis by the international terminology but pollinosis includes many other symptoms and so we will use the term Ambrosia pollinosis in this article. The characteristics of ragweed pollinosis are: severity, duration from August to September and the presence of asthma and/or tracheitis in about 50% of cases. Ambrosia: phanerogam, dicotyledon, annual plant, monoic. In France, fields in the mid Rhône Valley are covered with Ambrosia artemisiifolia L. but Ambrosia trifida L. is rare. The French Foundation For Ragweed Study (AFEDA) reports here 30years of clinical and epidemiological studies, involving considerable expense, that describe the geographic distribution of this pollinosis in Europe, and applies a predictive model of Ambrosia pollination to an appropriate treatment thanks to a sensitive sensor (Cour pollen trap). The spreading of Ambrosia is partly due to the regulations of the Common Agricultural Policy. There are numerous allergens; recently the major allergen of mugwort has been identified in ragweed. Profilins cause hypersensitivity reactions to certain foods. Genetic predisposition to developing this pollinosis is discussed because sometimes: the disease starts late in life, no personal or family history of atopy is found, immunoglobulin levels are low. Some publications have discussed a genetic predisposition to allergies to Juniperus ashei (United-States) and Cryptomeria japonica (Japan). The clinical efficacy of sublingual specific immunotherapy is well established and well accepted by patients. PMID:23664290

  4. Ambrosia beetle fungiculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ambrosia beetle fungiculture, as evidenced by the 11 independent origins and 3,500 species of ambrosia beetles, represents one of the most ecologically and evolutionarily successful symbioses. This presentation focuses on the discovery of a clade within the filamentous fungus Fusarium that is associ...

  5. Transitory effects of elevated atmospheric CO₂ on fine root dynamics in an arid ecosystem do not increase long-term soil carbon input from fine root litter.

    PubMed

    Ferguson, Scot D; Nowak, Robert S

    2011-06-01

    Experimental increases in atmospheric CO₂ often increase root production over time, potentially increasing soil carbon (C) sequestration. Effects of elevated atmospheric CO₂ on fine root dynamics in a Mojave desert ecosystem were examined for the last 4.5 yr of a long-term (10-yr) free air CO₂ enrichment (FACE) study at the Nevada desert FACE facility (NDFF). Sets of minirhizotron tubes were installed at the beginning of the NDFF experiment to characterize rooting dynamics of the dominant shrub Larrea tridentata, the codominant shrub Ambrosia dumosa and the plant community as a whole. Although significant treatment effects occurred sporadically for some fine root measurements, differences were transitory and often in opposite directions during other time-periods. Nonetheless, earlier root growth under elevated CO₂ helped sustain increased assimilation and shoot growth. Overall CO₂ treatment effects on fine root standing crop, production, loss, turnover, persistence and depth distribution were not significant for all sampling locations. These results were similar to those that occurred near the beginning of the NDFF experiment but unlike those in other ecosystems. Thus, increased C input into soils is unlikely to occur from fine root litter under elevated atmospheric CO₂ in this arid ecosystem. PMID:21355868

  6. Biology, Behavior, and Management of Ambrosia Beetles Attacking Ornamental Nursery Stock

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ambrosia beetles are being increasingly recognized as significant pests of field-grown ornamental nursery stock. Two species are especially problematic in ornamental nurseries, namely the black stem borer, Xylosandrus germanus, and the granulate ambrosia beetle, Xylosandrus crassiusculus. Ambrosia b...

  7. Systematics of Fusaria associated with Ambrosia beetles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Here, I summarize research efforts directed at characterizing ambrosia beetle-associated fusaria, including the species responsible for avocado wilt in Israel (Mendel et al., Phytoparasitica 2012) and branch dieback in California (Eskalen et al., Pl. Dis. 2012). Our multilocus molecular phylogenetic...

  8. New sesquiterpene lactones from Ambrosia cumanensis Kunth.

    PubMed

    Jimenez-Usuga, Nora Del Socorro; Malafronte, Nicola; Cotugno, Roberta; De Leo, Marinella; Osorio, Edison; De Tommasi, Nunziatina

    2016-09-01

    Eleven sesquiterpene lactones, including three new natural products (1-3), were isolated from the n-butanolic extract of Ambrosia cumanensis Kunth. aerial parts. The structure of all isolated compounds was elucidated by 1D- and 2D-NMR, and MS analyses. All compounds were tested for their antiproliferative activity on HeLa, Jurkat, and U937 cell lines. Compound 3, 2,3-dehydropsilostachyn C, showed cytotoxic activity with different potency in all cell lines. By means of flow cytometric studies, compound 3 was demonstrated to induce in Jurkat cells a G2/M cell cycle block, while in U937 elicited both cytostatic and cytotoxic responses. PMID:27491754

  9. An inordinate fondness for Fusarium: Phylogenetic diversity of fusaria cultivated by Euwallacea ambrosia beetles on avocado and other plant hosts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ambrosia beetle fungiculture represents one of the most ecologically and evolutionarily successful symbioses. Here we document the evolution of a clade within Fusarium associated with ambrosia beetles in the genus Euwallacea (Coleoptera: Scolytinae). Ambrosia Fusarium Clade (AFC) symbionts are unusu...

  10. New sesquiterpenoids from Ambrosia artemisiifolia L.

    PubMed

    Ding, Wenbing; Huang, Rui; Zhou, Zhongshi; Li, Youzhi

    2015-01-01

    A new pseudoguaianolide 1 and two new guaiane-type sesquiterpene glucosides 2 and 3, were isolated from the aerial parts of Ambrosia artemisiifolia L together with two known sesquiterpene dilactones 4 and 5. The new compounds were determined on the basis of spectroscopic and chemical methods to be 3β-acetoxy-4β-hydroxy-1α,7α, 10β,11αH-pseudoguaia-12,8β-olide (1), 1β,7β,9β,10β,13αH-guaia-4(5)-en-12,6β-olide 9-O-β-d-glucoside (2) and 4β-hydroxy-1α,5α,7α,9αH-guaia-10(14),11(13)-dien-12-acid 9-O-β-d-glucoside (3). The isolated compounds were evaluated for cytotoxicity against human promyelocytic leukemia HL-60 cell lines in vitro, but were all inactive. PMID:25764487

  11. Discordant phylogenies suggest repeated host shifts in the Fusarium–Euwallacea ambrosia beetle mutualism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mutualism between xyleborine beetles in the genus Euwallacea (Coleoptera: Curculionidae: Scolytinae) and members of the Ambrosia Fusarium Clade (AFC) represents one of 11 known independent evolutionary origins of fungiculture by ambrosia beetles. Female Euwallacea beetles transport fusarial symb...

  12. Phylogeny of ambrosia beetle symbionts in the genus Raffaelea.

    PubMed

    Dreaden, Tyler J; Davis, John M; de Beer, Z Wilhelm; Ploetz, Randy C; Soltis, Pamela S; Wingfield, Michael J; Smith, Jason A

    2014-12-01

    The genus Raffaelea was established in 1965 when the type species, Raffaelea ambrosia, a symbiont of Platypus ambrosia beetles was described. Since then, many additional ambrosia beetle symbionts have been added to the genus, including the important tree pathogens Raffaelea quercivora, Raffaelea quercus-mongolicae, and Raffaelea lauricola, causal agents of Japanese and Korean oak wilt and laurel wilt, respectively. The discovery of new and the dispersal of described species of Raffaelea to new areas, where they can become invasive, presents challenges for diagnosticians as well as plant protection and quarantine efforts. In this paper, we present the first comprehensive multigene phylogenetic analysis of Raffaelea. As it is currently defined, the genus was found to not be monophyletic. On the basis of this work, Raffaelea sensu stricto is defined and the affinities of undescribed isolates are considered. PMID:25457944

  13. Chemical ecology of the redbay ambrosia beetle (Xyleborus glabratus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in the U.S. in 2002 near Savannah, Georgia. Females of X. glabratus vector a newly-described fungal pathogen (Raffaelea lauricola) that causes laurel wilt, a lethal disease of trees in the family Lauraceae...

  14. The redbay ambrosia beetle, Xyleborus glabratus: A threat to avocado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laurel wilt (LW) is a disease caused by Raffaelea sp., a fungal symbiont associated with the recently-introduced redbay ambrosia beetle (RAB), Xyleborus glabratus. Impact of RAB as a vector of the disease to avocado is a threat to avocado production in the U.S. Since 2006, we have a) tested suscepti...

  15. The Pannonian plain as a source of Ambrosia pollen in the Balkans.

    PubMed

    Sikoparija, B; Smith, M; Skjøth, C A; Radisić, P; Milkovska, S; Simić, S; Brandt, J

    2009-05-01

    This study aims to find likely sources of Ambrosia pollen recorded during 2007 at five pollen-monitoring sites in central Europe: Novi Sad, Ruma, Negotin and Nis (Serbia) and Skopje (Macedonia). Ambrosia plants start flowering early in the morning and so Ambrosia pollen grains recorded during the day are likely to be from a local source. Conversely, Ambrosia pollen grains recorded at night or very early in the morning may have arrived via long-range transport. Ambrosia pollen counts were analysed in an attempt to find possible sources of the pollen and to identify Ambrosia pollen episodes suitable for further investigation using back-trajectory analysis. Diurnal variations and the magnitude of Ambrosia pollen counts during the 2007 Ambrosia pollen season showed that Novi Sad and Ruma (Pannonian Plain) and to a lesser degree Negotin (Balkans) were located near to sources of Ambrosia pollen. Mean bi-hourly Ambrosia pollen concentrations peaked during the middle of the day, and concentrations at these sites were notably higher than at Nis and Skopje. Three episodes were selected for further analysis using back-trajectory analysis. Back-trajectories showed that air masses brought Ambrosia pollen from the north to Nis and, on one occasion, to Skopje (Balkans) during the night and early morning after passing to the east of Novi Sad and Ruma during the previous day. The results of this study identified the southern part of the Pannonian Plain around Novi Sad and Ruma as being a potential source region for Ambrosia pollen recorded at Nis and Skopje in the Balkans. PMID:19224251

  16. Patterns of functional enzyme activity in fungus farming ambrosia beetles

    PubMed Central

    2012-01-01

    Introduction In wood-dwelling fungus-farming weevils, the so-called ambrosia beetles (Curculionidae: Scolytinae and Platypodinae), wood in the excavated tunnels is used as a medium for cultivating fungi by the combined action of digging larvae (which create more space for the fungi to grow) and of adults sowing and pruning the fungus. The beetles are obligately dependent on the fungus that provides essential vitamins, amino acids and sterols. However, to what extent microbial enzymes support fungus farming in ambrosia beetles is unknown. Here we measure (i) 13 plant cell-wall degrading enzymes in the fungus garden microbial consortium of the ambrosia beetle Xyleborinus saxesenii, including its primary fungal symbionts, in three compartments of laboratory maintained nests, at different time points after gallery foundation and (ii) four specific enzymes that may be either insect or microbially derived in X. saxesenii adult and larval individuals. Results We discovered that the activity of cellulases in ambrosia fungus gardens is relatively small compared to the activities of other cellulolytic enzymes. Enzyme activity in all compartments of the garden was mainly directed towards hemicellulose carbohydrates such as xylan, glucomannan and callose. Hemicellulolytic enzyme activity within the brood chamber increased with gallery age, whereas irrespective of the age of the gallery, the highest overall enzyme activity were detected in the gallery dump material expelled by the beetles. Interestingly endo-β-1,3(4)-glucanase activity capable of callose degradation was identified in whole-body extracts of both larvae and adult X. saxesenii, whereas endo-β-1,4-xylanase activity was exclusively detected in larvae. Conclusion Similar to closely related fungi associated with bark beetles in phloem, the microbial symbionts of ambrosia beetles hardly degrade cellulose. Instead, their enzyme activity is directed mainly towards comparatively more easily accessible hemicellulose

  17. Symbiont diversification in ambrosia beetles: Diversity of fungi associated with exotic scolytine beetles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In virtually every forest habitat, ambrosia beetles (Coleoptera: Curculionidae: Scolytinae, Platypodinae) plant and maintain symbiotic fungus gardens inside dead or dying wood. Some introduced ambrosia beetles aggressively attack live trees and can damage tree crops, lumber, and native woody plant t...

  18. Diversity of Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae) Attracted to Avocado, Lychee, and Essential Oil Lures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field trapping studies conducted in north-central Florida for the redbay ambrosia beetle (Xyleborus glabratus) captured numerous non-target ambrosia beetles, providing information on species diversity and relative abundance. Traps (Lindgren and sticky) baited with essential oil lures (manuka and p...

  19. Seasonal and spatial dispersal patterns of ambrosia beetles (Coleoptera: curculionidae) from forest habitats into production nurseries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic ambrosia beetles (Coleoptera: Curculionidae) are important pests of tree nurseries. While they are known to migrate in early spring from peripheral forested areas into nurseries, there are few data to show how far ambrosia beetles will fly to infest new host trees, or whether a mass trapping...

  20. Ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) captures using colored traps in southeast Tennessee and south Mississippi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ambrosia beetles have become a major problem for nursery production, with controls centered around an accurate monitoring program. While the use of semiochemicals by ambrosia beetles is well understood, their potential use of visual cues including color remains relatively understudied. Field tests...

  1. Ambrosia airborne pollen concentration modelling and evaluation over Europe

    NASA Astrophysics Data System (ADS)

    Hamaoui-Laguel, Lynda; Vautard, Robert; Viovy, Nicolas; Khvorostyanov, Dmitry; Colette, Augustin

    2014-05-01

    Native from North America, Ambrosia artemisiifolia L. (Common Ragweed) is an invasive annual weed introduced in Europe in the mid-nineteenth century. It has a very high spreading potential throughout Europe and releases very allergenic pollen leading to health problems for sensitive persons. Because of its health effects, it is necessary to develop modelling tools to be able to forecast ambrosia air pollen concentration and to inform allergy populations of allergenic threshold exceedance. This study is realised within the framework of the ATOPICA project (https://www.atopica.eu/) which is designed to provide first steps in tools and estimations of the fate of allergies in Europe due to changes in climate, land use and air quality. To calculate and predict airborne concentrations of ambrosia pollen, a chain of models has been built. Models have been developed or adapted for simulating the phenology (PMP phonological modelling platform), inter-annual production (ORCHIDEE vegetation model), release and airborne processes (CHIMERE chemical transport model) of ragweed pollen. Airborne pollens follow processes similar to air quality pollutants in CHIMERE with some adaptations. The detailed methodology, formulations and input data will be presented. A set of simulations has been performed to simulate airborne concentrations of pollens over long time periods on a large European domain. Hindcast simulations (2000 - 2012) driven by ERA-Interim re-analyses are designed to best simulate past periods airborne pollens. The modelled pollen concentrations are calibrated with observations and validated against additional observations. Then, 20-year long historical simulations (1986 - 2005) are carried out using calibrated ambrosia density distribution and climate model-driven weather in order to serve as a control simulation for future scenarios. By comparison with multi-annual observed daily pollen counts we have shown that the model captures well the gross features of the pollen

  2. Examining Ambrosia pollen episodes at Poznań (Poland) using back-trajectory analysis

    NASA Astrophysics Data System (ADS)

    Stach, A.; Smith, M.; Skjøth, C. A.; Brandt, J.

    2007-03-01

    The pollen grains of Ambrosia spp. are considered to be important aeroallergens in parts of southern and central Europe. Back-trajectories have been analysed with the aim of finding the likely sources of Ambrosia pollen grains that arrived at Poznań (Poland). Temporal variations in Ambrosia pollen at Poznań from 1995-2005 were examined in order to identify Ambrosia pollen episodes suitable for further investigation using back-trajectory analysis. The trajectories were calculated using the transport model within the Lagrangian air pollution model, ACDEP (Atmospheric Chemistry and Deposition). Analysis identified two separate populations in Ambrosia pollen episodes, those that peaked in the early morning between 4 a.m. and 8 a.m., and those that peaked in the afternoon between 2 p.m. and 6 p.m.. Six Ambrosia pollen episodes between 2001 and 2005 were examined using back-trajectory analysis. The results showed that Ambrosia pollen episodes that peaked in the early morning usually arrived at Poznań from a southerly direction after passing over southern Poland, the Czech Republic, Slovakia and Hungary, whereas air masses that brought Ambrosia pollen to Poznań during the afternoon arrived from a more easterly direction and predominantly stayed within the borders of Poland. Back-trajectory analysis has shown that there is a possibility that long-range transport brings Ambrosia pollen to Poznań from southern Poland, the Czech Republic, Slovakia and Hungary. There is also a likelihood that Ambrosia is present in Poland, as shown by the arrival of pollen during the afternoon that originated primarily from within the country.

  3. [Effects of nitrogen and carbon addition and arbuscular mycorrhiza on alien invasive plant Ambrosia artemisiifolia].

    PubMed

    Huang, Dong; Sang, Wei-guo; Zhu, Li; Song, Ying-ying; Wang, Jin-ping

    2010-12-01

    A greenhouse control experiment was conducted to explore the effects of nitrogen and carbon addition and arbuscular mycorrhiza (AM) on the growth of alien invasive plant Ambrosia artemisiifolia (common ragweed). Nitrogen addition had no significant effects on the morphological indices, biomass and its allocation, and absolute growth rate of A. artemisiifolia, but increased the nitrogen content in the aboveground and underground parts of the plant significantly. Carbon addition increased the content of soil available nitrogen. In this case, the biomass allocation in root system for nutrient (nitrogen) absorption promoted, resulting in a remarkable decrease of branch number, total leaf area, specific leaf area (SLA), and leaf mass ratio. As a result, the total biomass decreased significantly. The symbiosis of A. artemisiifolia and AM fungi had great influence on the common ragweed's soil nitrogen acclimation, which enhanced its resource-capture by the increase of SLA, and this effect was more significant when the soil nitrogen content was low. AM fungi played an important role in the growth of A. artemisiifolia in low-nitrogen environment. PMID:21442989

  4. Green ambrosia for Soil- Dry Cow Dung Powder: Rhexistasy to Biostasy

    NASA Astrophysics Data System (ADS)

    Bagla, Hemlata; Barot, Nisha

    2013-04-01

    "Greener ambrosia for Soil - Dry cow dung powder: Rhexistasy to Biostasy" Pedosphere, the soil with its biotic and abiotic component, is produced by lithosphere`s interactions with atmosphere, hydrosphere and biosphere. The theory of Biorhexistasy proposed by pedologist H. Erhart [1], describes two crucial climatic phases of soil i.e. Biostasy, period of soil formation and Rhexistasy, periods of soil erosion. Humus, the organic matter in soil, permits better aeration, enhances the absorption and releases nutrients, and makes the soil less susceptible to leaching and erosion [2], thus the agent of soil`s vitality. Mismanagement of soil, leads to the degradation of millions of acres of land through erosion, compaction, salinization and acidification. Among these threats salinity is a major abiotic stress reducing the yield of wide variety of crops all over the world [3]. It is been proved that Humic Acid (HA) treatment can ameliorate the deleterious effects of salt stress by increasing root growth, altering mineral uptake, and decreasing membrane damage, thus inducing salt tolerance in plants [4]. HA can be inexpensively incorporated into soils via different biowastes. Dry cow dung powder (DCP), is naturally available bio-organic, complex, polymorphic humified fecal matter, enriched with minerals, carbohydrates, fats, proteins, bile pigments, aliphatic - aromatic species such as HA, Fulvic Acid (FA) etc [5]. The microbial consortium enables DCP with considerable potentials for biodegradation and biotransformation of even saline soil and further contributes to many biogeochemical processes, boosting humus content of soil. Due to unambiguous biological, microbiological as well as chemical inert properties of DCP, it has been successfully utilized as a fertilizer and soil conditioner since ages in India, one of the leading agrarian countries of the world. Thus we summarize that DCP is one of the best contenders for the biostasy and desaliner of soil, aptly, soil

  5. Environmental Assessment of remedial action at the Ambrosia Lake uranium mill tailings site, Ambrosia Lake, New Mexico

    SciTech Connect

    Not Available

    1987-06-01

    This document assesses and compares the environmental impacts of various alternatives for remedial action at the Ambrosia Lake uranium mill tailings site located near Ambrosia Lake, New Mexico. The designated site covers 196 acres and contains 111 acres of tailings and some of the original mill structures. The Uranium Mill Tailings Radiation Control Act (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for th remedial action (40 CFR Part 192). Remedial action must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion protection measures would be taken to assure the long-term stability of the pile. Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at an undeveloped location. The no action alternative is also assessed in this document.

  6. Ethanol injection of ornamental trees facilitates testing insecticide efficacy against ambrosia beetles (Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic ambrosia beetles are damaging pests in ornamental tree nurseries in North America. The species Xylosandrus crassiusculus (Motshulsky) and Xylosandrus germanus (Blandford) are especially problematic. Management of these pests relies on preventive treatments of insecticides. However, field t...

  7. Spatio-Temporal Distribution of Bark and Ambrosia Beetles in a Brazilian Tropical Dry Forest

    PubMed Central

    de Novais, Samuel Matos Antunes; Monteiro, Graziela França; Flechtmann, Carlos Alberto Hector; de Faria, Maurício Lopes; Neves, Frederico de Siqueira

    2016-01-01

    Bark and the ambrosia beetles dig into host plants and live most of their lives in concealed tunnels. We assessed beetle community dynamics in tropical dry forest sites in early, intermediate, and late successional stages, evaluating the influence of resource availability and seasonal variations in guild structure. We collected a total of 763 beetles from 23 species, including 14 bark beetle species, and 9 ambrosia beetle species. Local richness of bark and ambrosia beetles was estimated at 31 species. Bark and ambrosia composition was similar over the successional stages gradient, and beta diversity among sites was primarily determined by species turnover, mainly in the bark beetle community. Bark beetle richness and abundance were higher at intermediate stages; availability of wood was the main spatial mechanism. Climate factors were effectively non-seasonal. Ambrosia beetles were not influenced by successional stages, however the increase in wood resulted in increased abundance. We found higher richness at the end of the dry and wet seasons, and abundance increased with air moisture and decreased with higher temperatures and greater rainfall. In summary, bark beetle species accumulation was higher at sites with better wood production, while the needs of fungi (host and air moisture), resulted in a favorable conditions for species accumulation of ambrosia. The overall biological pattern among guilds differed from tropical rain forests, showing patterns similar to dry forest areas. PMID:27271969

  8. Spatio-Temporal Distribution of Bark and Ambrosia Beetles in a Brazilian Tropical Dry Forest.

    PubMed

    Macedo-Reis, Luiz Eduardo; Novais, Samuel Matos Antunes de; Monteiro, Graziela França; Flechtmann, Carlos Alberto Hector; Faria, Maurício Lopes de; Neves, Frederico de Siqueira

    2016-01-01

    Bark and the ambrosia beetles dig into host plants and live most of their lives in concealed tunnels. We assessed beetle community dynamics in tropical dry forest sites in early, intermediate, and late successional stages, evaluating the influence of resource availability and seasonal variations in guild structure. We collected a total of 763 beetles from 23 species, including 14 bark beetle species, and 9 ambrosia beetle species. Local richness of bark and ambrosia beetles was estimated at 31 species. Bark and ambrosia composition was similar over the successional stages gradient, and beta diversity among sites was primarily determined by species turnover, mainly in the bark beetle community. Bark beetle richness and abundance were higher at intermediate stages; availability of wood was the main spatial mechanism. Climate factors were effectively non-seasonal. Ambrosia beetles were not influenced by successional stages, however the increase in wood resulted in increased abundance. We found higher richness at the end of the dry and wet seasons, and abundance increased with air moisture and decreased with higher temperatures and greater rainfall. In summary, bark beetle species accumulation was higher at sites with better wood production, while the needs of fungi (host and air moisture), resulted in a favorable conditions for species accumulation of ambrosia. The overall biological pattern among guilds differed from tropical rain forests, showing patterns similar to dry forest areas. PMID:27271969

  9. The weeding of Ambrosia artemisiifolia and sanitary risks.

    PubMed

    Zicari, Giuseppe; Soardo, Vincenzo; Rivetti, Daniela; Cerrato, Elena; Russo, Domenico

    2013-01-01

    Ambrosia artemisiifolia is a potentially allergenic annual herbaceous plant coming from North America and widespread in Italy, where it can be easily seen since May-April. Its pollination is mainly windborne and each plant is able to produce billions of pollen grains. The pollen peaks are in the hottest days in the absence of rain and wind. In susceptible individuals, the great amount of pollen produced by this species may cause rhinitis and severe asthma attacks. Some allergic subjects can manifest disorders already at a concentration of a few granules per cubic metre. Chemical control is often practiced on a large scale and uses herbicides. A major risk is the result of the unprofessional use of chemicals by the population, especially in residential or very busy areas (eg railways, urban areas). In this paper we propose preventive measures of chemical hazards that may be resulting from the excessive use of plant protection products. PMID:23903038

  10. Comparative efficacy of plant-derived essential oils for managing Ambrosia beetles (Coleoptera: Curculionidae: Scolytiniae) and their corresponding mass spectral characterization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ambrosia beetles pose a significant challenge to producers of ornamental nursery stock. Conventional insecticides are commonly used for management purposes, but botanical formulations may also discourage ambrosia beetles from initiating attacks. In order to identify promising formulations, field-bas...

  11. Suitability of California bay laurel and other species as potential hosts for the non-native redbay ambrosia beetle and granulate ambrosia beetle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle (Xyleborus glabratus Eichhoff) is a non-native invasive forest pest and vector of the pathogen that causes laurel wilt, a deadly disease of trees in the family Lauraceae in the southeastern United States (U.S.). Concern exists that X. glabratus and its fungal symbiont cou...

  12. Fungal symbionts in three exotic ambrosia beetles, Xylosandrus amputatus, Xyleborinus andrewesi, and Dryoxylon onoharaense (Coleoptera: Curculionidae: Scolytinae: Xyleborini) in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract In nearly every forest habitat, ambrosia beetles (Coleoptera: Curculionidae: Scolytinae, Platypodinae) plant and maintain symbiotic fungus gardens inside dead or dying trees. Some non-native ambrosia beetles aggressively attack live trees and damage tree crops, lumber, and native woody pla...

  13. In Vitro Antiplasmodial Activity of Sesquiterpene Lactones from Ambrosia tenuifolia

    PubMed Central

    Sülsen, V.; Gutierrez Yappu, D.; Laurella, L.; Anesini, C.; Gimenez Turba, A.; Martino, V.; Muschietti, L.

    2011-01-01

    The in vitro antiplasmodial activity of Ambrosia tenuifolia organic extract and its isolated sesquiterpene lactones, psilostachyin and peruvin, has been evaluated against Plasmodium falciparum F32 and W2 strains. The cytotoxicity of both compounds was determined on lymphoid cells, and their corresponding selectivity indexes (SIs) were calculated. Peruvin was the most active compound on F32 strain of P. falciparum with a 50% inhibitory concentration value (IC50) of 0.3 μg/mL (1.1 μM) whereas psilostachyin showed activity on both strains (IC50 = 0.6 (2.1 μM) and 1.8 μg/mL (6.4 μM)). Fifty percent cytotoxic concentration (CC50) values (48 h) were 6.8 μg/mL (24.3 μM) and 10.0 μg/mL (37.9 μM) for psilostachyin and peruvin, respectively. PMID:21716685

  14. Bark and Ambrosia Beetles Show Different Invasion Patterns in the USA

    PubMed Central

    Rassati, Davide; Faccoli, Massimo; Haack, Robert A.; Rabaglia, Robert J.; Petrucco Toffolo, Edoardo; Battisti, Andrea; Marini, Lorenzo

    2016-01-01

    Non-native bark and ambrosia beetles represent a threat to forests worldwide. Their invasion patterns are, however, still unclear. Here we investigated first, if the spread of non-native bark and ambrosia beetles is a gradual or a discontinuous process; second, which are the main correlates of their community structure; third, whether those correlates correspond to those of native species. We used data on species distribution of non-native and native scolytines in the continental 48 USA states. These data were analyzed through a beta-diversity index, partitioned into species richness differences and species replacement, using Mantel correlograms and non-metric multidimensional scaling (NMDS) ordination for identifying spatial patterns, and regression on distance matrices to test the association of climate (temperature, rainfall), forest (cover area, composition), geographical (distance), and human-related (import) variables with β-diversity components. For both non-native bark and ambrosia beetles, β-diversity was mainly composed of species richness difference than species replacement. For non-native bark beetles, a discontinuous invasion process composed of long distance jumps or multiple introduction events was apparent. Species richness differences were primarily correlated with differences in import values while temperature was the main correlate of species replacement. For non-native ambrosia beetles, a more continuous invasion process was apparent, with the pool of non-native species arriving in the coastal areas that tended to be filtered as they spread to interior portions of the continental USA. Species richness differences were mainly correlated with differences in rainfall among states, while rainfall and temperature were the main correlates of species replacement. Our study suggests that the different ecology of bark and ambrosia beetles influences their invasion process in new environments. The lower dependency that bark beetles have on climate

  15. Improved lure for redbay ambrosia beetle developed by enrichment of a-copaene content

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the past decade, the exotic redbay ambrosia beetle, Xyleborus glabratus Eichhoff, has become a serious invasive pest in the USA, now established in seven southeastern states. Females are the primary vectors of a fungal pathogen, Raffaelea lauricola, that causes laurel wilt, a lethal disease of...

  16. Another Asian ambrosia bark beetle, Xyleborinus artestriatus (Eichhoff) (Coleoptera: Curculionidae: Scolytinae), found in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xyleborinus artestriatus (Eichhoff), an ambrosia beetle native to Asia, is reported for the first time in North America based on specimens from Georgia and Texas. This is the twenty-fourth species of exotic Xyleborina documented in North America. North American distributional records, key identifica...

  17. Chemical Control of the Redbay Ambrosia Beetle, Xyleborus glabratus (Coleoptera: Scolytinae) in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), is an exotic pest of U.S. trees in the family Lauraceae, including avocado (Persea americana) and redbay (P. borbonia). It threatens avocado production in Florida by transmitting Raffaelea lauricola, the fungal...

  18. Host-based attractants for the redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle (RAB) is an exotic wood-borer that vectors the fungus responsible for laurel wilt, a lethal vascular disease of trees in the Lauraceae, including avocado. There is a critical need for effective attractants to detect and control the spread of RAB. We report results of fie...

  19. Optimizing ethanol-baited traps for monitoring damaging ambrosia beetles (Coleoptera: Curculionidae, Scolytinae) in ornamental nurseries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The exotic ambrosia beetles Xylosandrus crassiusculus (Motschulsky) and Xylosandrus germanus (Blandford) are serious pests in ornamental tree nurseries. We tested different rates of commercially available pouch-style ethanol lures in bottle-traps to optimize bottle-traps as a monitoring system for ...

  20. Host preferences of the redbay ambrosia beetle (Xyleborus glabratus) in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), is an exotic wood-boring insect that vectors Raffaelea lauricola, the fungal pathogen responsible for laurel wilt. Laurel wilt is a newly-described vascular disease of U.S. trees in the family Lauracea...

  1. Comparison of ambrosia beetle communities in two host with laurel wilt: swampbay vs. avocado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The invasive redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), is an exotic wood-boring pest first detected in 2002 near Savannah, Georgia. The beetle’s dominant fungal symbiont, Raffaelea lauricola, is the pathogen that causes laurel wilt, a lethal disease of tre...

  2. Method for collection of live redbay ambrosia beetles, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is the only confirmed vector of laurel wilt, a newly-described lethal disease of trees in the family Lauraceae, including avocado. First detected in the U.S. near Savannah, Georgia, X. glabratus has since spread to the Carolinas, Florida, Al...

  3. Electrophysiological and Behavioral Responses of the Ambrosia Beetle, Xylosandrus germanus, to Repellent Formulations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic ambrosia beetles are increasingly being recognized as key pests of ornamental nursery stock, and Xylosandrus germanus is one of the most problematic species. Conventional insecticides are used almost exclusively by growers in an attempt to prevent attacks by X. germanus. Due to the importance...

  4. Host preferences / relative attraction of the Lauraceae to redbay ambrosia beetle, Xyleborus glabratus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), is an exotic wood-boring insect that vectors Raffaelea lauricola, the fungal pathogen responsible for laurel wilt. Laurel wilt is a newly-described vascular disease of U.S. trees in the family Lauracea...

  5. Non-native ambrosia beetles as opportunistic exploiters of living but weakened trees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic Xylosandrus spp. ambrosia beetles have been associated with sudden and extensive attacks on trees after their introduction into new ecosystems, but factors driving their host selection are poorly understood and critical for developing management tactics. The overall goal of this study was to ...

  6. Development of a kairomone-based monitoring tool for the invasive redbay ambrosia beetle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is an exotic wood-borer that vectors the fungal agent responsible for laurel wilt. This disease has had severe impact on forest ecosystems, and has spread to eight states in the southeastern US since the first detection of the beetle in Georg...

  7. Efficacy of current lures for detection of redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since its introduction into the USA in 2002, the exotic redbay ambrosia beetle, Xyleborus glabratus Eichhoff, has become a serious invasive pest, currently established in eight southeastern states. Females are the primary vectors of a pathogenic fungus, Raffaelea lauricola, that causes laurel wilt....

  8. Attraction of Redbay Ambrosia Beetle (Coleoptera: Curculionidae: Scolytinae) to Avocado, Lychee, and Essential Oil Lures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle (RAB, Xyleborus glabratus) is a wood-boring pest that vectors laurel wilt, a lethal vascular disease that currently threatens Florida avocados. Field and laboratory studies were conducted to evaluate attraction of RAB to avocado wood (three races), lychee wood, and two co...

  9. Diversity abundance and seasonality of ambrosia beetles (Coleoptera: curculionida) in Southern Mississippi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A survey was undertaken in 2010 to assess the makeup of the ambrosia beetle (Coleoptera: Curculionidae) community at two research sites in South Mississippi. Inexpensive beetle traps were constructed and fitted with ethanol lures, with bi-weekly collections made from March through November. The gr...

  10. Attraction of the redbay ambrosia beetle, Xyleborus glabratus to avocado, lychee, and essential oil lures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), is an exotic wood-boring insect that vectors the mycopathogen responsible for laurel wilt, a lethal vascular disease of trees in the Lauraceae. High mortality has occurred in native Persea species in ...

  11. Efficacy of essential oil lures for detection of redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle (RAB) is a wood borer that vectors laurel wilt, a lethal vascular disease of trees in the Lauraceae, including avocado. Field tests and chemical analyses were conducted with commercial lures of manuka oil and phoebe oil to (1) compare efficacy of lures for capture of RAB,...

  12. Repeated evolution of crop theft in fungus-farming ambrosia beetles.

    PubMed

    Hulcr, Jiri; Cognato, Anthony I

    2010-11-01

    Ambrosia beetles, dominant wood degraders in the tropics, create tunnels in dead trees and employ gardens of symbiotic fungi to extract nutrients from wood. Specificity of the beetle-fungus relationship has rarely been examined, and simple vertical transmission of a specific fungal cultivar by each beetle species is often assumed in literature. We report repeated evolution of fungal crop stealing, termed mycocleptism, among ambrosia beetles. The mycocleptic species seek brood galleries of other species, and exploit their established fungal gardens by tunneling through the ambient mycelium-laden wood. Instead of carrying their own fungal sybmbionts, mycocleptae depend on adopting the fungal assemblages of their host species, as shown by an analysis of fungal DNA from beetle galleries. The evidence for widespread horizontal exchange of fungi between beetles challenges the traditional concept of ambrosia fungi as species-specific symbionts. Fungus stealing appears to be an evolutionarily successful strategy. It evolved independently in several beetle clades, two of which have radiated, and at least one case was accompanied by a loss of the beetles' fungus-transporting organs. We demonstrate this using the first robust phylogeny of one of the world's largest group of ambrosia beetles, Xyleborini. PMID:20633043

  13. Ambrosia beetle communities in forest and agriculture ecosystems with laurel wilt disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The invasive redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in 2002 near Savannah, Georgia. The beetle’s dominant fungal symbiont, Raffaelea lauricola, is the pathogen that causes laurel wilt, a lethal disease of trees in the family Lauraceae. Redbay ambro...

  14. Developing a media moisture threshold for nurseries to reduce tree stress and ambrosia beetle attacks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic ambrosia beetles are among the most damaging pests of trees grown in nurseries. The primary pests Xylosandrus crassiusculus Motschulsky and Xylosandrus germanus Blandford use ethanol to locate vulnerable trees. Research, primarily with X. germanus, has shown that flood-stressed trees emit eth...

  15. Biology, ecology, and management of Xylosandrus spp. ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) in ornamental tree nurseries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xylosandrus germanus (Blandford) and Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae: Scolytinae) are two of the most damaging non-native ambrosia beetle pests in ornamental tree nurseries. Adult females tunnel into the stems and branches of host trees to create galleries with bro...

  16. Cubeb oil identified as an improved attractant for redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Redbay ambrosia beetle (RAB), Xyleborus glabratus Eichhoff, is an exotic wood-borer that vectors the fungal agent (Raffaelea lauricola) responsible for laurel wilt disease. Since its introduction into Georgia in 2002, RAB has spread throughout the southeastern USA, and laurel wilt has decimated lar...

  17. Developing a Media Moisture Threshold for Nurseries to Reduce Tree Stress and Ambrosia Beetle Attacks.

    PubMed

    Frank, Steven D; Ranger, Christopher M

    2016-08-01

    Exotic ambrosia beetles are among the most damaging pests of trees grown in nurseries. The primary pests Xylosandrus crassiusculus Motschulsky and Xylosandrus germanus Blandford use ethanol to locate vulnerable trees. Research, primarily with X. germanus, has shown that flood-stressed trees emit ethanol and are preferentially attacked by ambrosia beetles. Our goal was to develop a media (also called potting soil) moisture threshold as an integrated pest management (IPM) tactic and assess grower practices that lead to ambrosia beetle attacks. Flooded Cornus florida L., Cornus kousa Burg., and Magnolia grandiflora L. trees incurred more attacks than unflooded trees that were not attacked. To determine optimal media moisture levels, we grew flood-tolerant Acer rubrum L. and flood-intolerant C. florida in containers with 10, 30, 50, 70, or 90% media moisture. No flooded or unflooded A. rubrum were attacked. However, C. florida grown in 70 or 90% moisture were attacked and died, whereas trees at 30 and 50% moisture were not attacked. Thus, we suggest an upper moisture threshold of 50% when growing C. florida and other flood-intolerant trees. However, during peak ambrosia beetle flight activity in spring 2013 and 2014, we found that media moisture levels in commercial nurseries were often between 50 and 90%. Implementing a media moisture threshold, as a new IPM tool, could reduce ambrosia beetle attacks and the need for insecticide applications, which is currently the only available management tactic. Future research should focus on how changes in substrates, irrigation, and other practices could help growers meet this threshold. PMID:27412195

  18. Final audit report of remedial action construction at the UMTRA Project Ambrosia Lake, New Mexico, site

    SciTech Connect

    1995-09-01

    The final audit report for remedial action at the Ambrosia Lake, New Mexico, Uranium Mill Tailings Remedial Action (UMTRA) Project site consists of a summary of the radiological surveillances/audits, quality assurance (QA) in-process surveillances, and a QA final closeout inspection performed by the US Department of Energy (DOE) and the Technical Assistance Contractor (TAC). One radiological surveillance and three radiological audits were performed at the Ambrosia Lake site. The surveillance was performed on 12--16 April 1993 (DOE, 1993d). The audits were performed on 26--29 July 1993 (DOE, 1993b); 21--23 March 1994 (DOE, 1994d); and 1--2 August 1994 (DOE, 1994d). The surveillance and audits resulted in 47 observations. Twelve of the observations raised DOE concerns that were resolved on site or through subsequent corrective action. All outstanding issues were satisfactorily closed out on 28 December 1994. The radiological surveillance and audits are discussed in this report. A total of seven QA in-process surveillances were performed at the Ambrosia Lake UMTRA site are discussed. The DOE/TAC Ambrosia Lake final remedial action close-out inspection was conducted on 26 July 1995 (DOE, 1995a). To summarize, a total of 155 observations were noted during DOE/TAC audit and surveillance activities. Follow-up to responses required from the RAC for the DOE/TAC surveillance and audit observations indicated that all issues related to the Ambrosia Lake site were resolved and closed to the satisfaction of the DOE.

  19. CONFIRMATORY SURVEY REPORT FOR THE SECTION 4 AREA AT THE RIO ALGOM AMBROSIA LAKE FACILITY NEW MEXICO

    SciTech Connect

    W.C. Adams

    2010-02-12

    The objectives of the confirmatory survey were to verify that remedial actions were effective in meeting established release criteria and that documentation accurately and adequately described the final radiological conditions of the RAM Ambrosia Lake, Section 4 Areas.

  20. MONITORING THE AMBROSIA BEETLE COMPLEX IN ORNAMENTAL NURSERIES IN OHIO, TENNESSEE, AND VIRGINIA: INFLUENCE OF TRAP HEIGHT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ambrosia beetles (Coleoptera: Curculionidae Scolytinae) are becoming increasing problems in ornamental tree nurseries. Xylosandrus crassiusculus has become especially worrisome to southeastern and Atlantic states. This species tends to attack healthy trees often killing their host. Management of ...

  1. Ambrosia artemisiifolia L. pollen simulations over the Euro-CORDEX domain: model description and emission calibration

    NASA Astrophysics Data System (ADS)

    liu, li; Solmon, Fabien; Giorgi, Filippo; Vautard, Robert

    2014-05-01

    Ragweed Ambrosia artemisiifolia L. is a highly allergenic invasive plant. Its pollen can be transported over large distances and has been recognized as a significant cause of hayfever and asthma (D'Amato et al., 2007). In the context of the ATOPICA EU program we are studying the links between climate, land use and ecological changes on the ragweed pollen emissions and concentrations. For this purpose, we implemented a pollen emission/transport module in the RegCM4 regional climate model in collaboration with ATOPICA partners. The Abdus Salam International Centre for Theoretical Physics (ICTP) regional climate model, i.e. RegCM4 was adapted to incorporate the pollen emissions from (ORCHIDEE French) Global Land Surface Model and a pollen tracer model for describing pollen convective transport, turbulent mixing, dry and wet deposition over extensive domains, using consistent assumption regarding the transport of multiple species (Fabien et al., 2008). We performed two families of recent-past simulations on the Euro-Cordex domain (simulation for future condition is been considering). Hindcast simulations (2000~2011) were driven by the ERA-Interim re-analyses and designed to best simulate past periods airborne pollens, which were calibrated with parts of observations and verified by comparison with the additional observations. Historical simulations (1985~2004) were driven by HadGEM CMPI5 and designed to serve as a baseline for comparison with future airborne concentrations as obtained from climate and land-use scenarios. To reduce the uncertainties on the ragweed pollen emission, an assimilation-like method (Rouǐl et al., 2009) was used to calibrate release based on airborne pollen observations. The observations were divided into two groups and used for calibration and validation separately. A wide range of possible calibration coefficients were tested for each calibration station, making the bias between observations and simulations within an admissible value then

  2. Effects of elevated CO2 on biomass and fungi associated with two ecotypes of ragweed (Ambrosia artemisiifolia L.)

    PubMed Central

    Runion, G. Brett; Prior, Stephen A.; Price, Andrew J.; McElroy, J. Scott; Torbert, H. Allen

    2014-01-01

    Herbicide resistant weed populations have developed due to the repeated application of herbicides. Elevated concentrations of atmospheric CO2 can have positive effects on weed growth, but how rising CO2 might affect herbicide resistant weeds is not known. Ragweed (Ambrosia artemisiifolia L.) ecotypes known to be resistant or susceptible to glyphosate herbicide were exposed to either ambient or elevated (ambient +200 μ mol mol−1) concentrations of CO2 in open top chambers. Plants were harvested following 8 weeks of CO2 exposure; at this time, they had begun to exhibit disease symptoms including spots on leaves and stems. Elevated CO2 significantly increased top, root, and total plant biomass. Also, glyphosate resistant plants had significantly greater top, root, and total biomass than plants susceptible to the herbicide. There were no significant CO2 by ecotype interactions. Fungi from 13 genera were associated with ragweed, several of which can be either pathogens (i.e., Alternaria, Fusarium, Rhizoctonia), aiding the decline in health of the ragweed plants, or saprophytes existing on dead plant tissues. The common foliar disease powdery mildew was significantly higher on susceptible compared with resistant ragweed. Susceptible plants also showed an increased frequency of Rhizoctonia on leaves and Alternaria on stems; however, Fusarium occurred more frequently on resistant ragweed leaves. Fungi were not affected by CO2 concentration or its interaction with ecotype. This study reports the first information on the effects of elevated CO2 on growth of herbicide resistant weeds. This is also the first study examining the impact of herbicide resistance and elevated CO2 on fungi associated with weeds. What effects herbicide resistance might have on plant diseases and how rising atmospheric CO2 might impact these effects needs to be addressed, not only with important weeds but also with crops. PMID:25309569

  3. Effects of elevated CO2 on biomass and fungi associated with two ecotypes of ragweed (Ambrosia artemisiifolia L.).

    PubMed

    Runion, G Brett; Prior, Stephen A; Price, Andrew J; McElroy, J Scott; Torbert, H Allen

    2014-01-01

    Herbicide resistant weed populations have developed due to the repeated application of herbicides. Elevated concentrations of atmospheric CO2 can have positive effects on weed growth, but how rising CO2 might affect herbicide resistant weeds is not known. Ragweed (Ambrosia artemisiifolia L.) ecotypes known to be resistant or susceptible to glyphosate herbicide were exposed to either ambient or elevated (ambient +200 μ mol mol(-1)) concentrations of CO2 in open top chambers. Plants were harvested following 8 weeks of CO2 exposure; at this time, they had begun to exhibit disease symptoms including spots on leaves and stems. Elevated CO2 significantly increased top, root, and total plant biomass. Also, glyphosate resistant plants had significantly greater top, root, and total biomass than plants susceptible to the herbicide. There were no significant CO2 by ecotype interactions. Fungi from 13 genera were associated with ragweed, several of which can be either pathogens (i.e., Alternaria, Fusarium, Rhizoctonia), aiding the decline in health of the ragweed plants, or saprophytes existing on dead plant tissues. The common foliar disease powdery mildew was significantly higher on susceptible compared with resistant ragweed. Susceptible plants also showed an increased frequency of Rhizoctonia on leaves and Alternaria on stems; however, Fusarium occurred more frequently on resistant ragweed leaves. Fungi were not affected by CO2 concentration or its interaction with ecotype. This study reports the first information on the effects of elevated CO2 on growth of herbicide resistant weeds. This is also the first study examining the impact of herbicide resistance and elevated CO2 on fungi associated with weeds. What effects herbicide resistance might have on plant diseases and how rising atmospheric CO2 might impact these effects needs to be addressed, not only with important weeds but also with crops. PMID:25309569

  4. Investigating atmospheric transport of Ambrosia pollen from the Pannonian Plain towards the Balkan region with DEHM-Pollen

    NASA Astrophysics Data System (ADS)

    Ambelas Skjoth, C.

    2009-04-01

    The pollen grains of Ambrosia spp. are considered to be important aeroallergens. The threshold value for clinical symptoms for ragweed pollen grains for the majority of sensitised patients is below 20 grains/m3. Ambrosia pollen appears to induce asthma about twice as often as other pollen. Each ragweed plant produces millions of pollen grains that are small (18-22 μm) and suitable for long-range transport when conditions are favourable. In this study we use DEHM-Pollen to investigate if the Pannonian Plain could be the source area for observed episodes of Ambrosia pollen in the Balkans. A possible Ambrosia pollen inventory for various regions in the Pannonian Plain was constructed using detailed land cover data from Serbia, Hungary, Austria, Croatia, Bosnia-Herzegovina, Slovakia, Romania and Czech Republic in combination with measurements of the annual load of Ambrosia pollen in the source areas. A simple unified pollen release model (SUPREME) was calibrated against daily measurements from Novi Sad in Serbia and implemented in DEHM-Pollen with the Ambrosia pollen inventory. Model simulations was then performed with DEHM-Pollen for the months August and September 2007 and compared with measurements from stations outside the Pannonian Plain. The simulations several times indicate regional scale transport from the Pannonian Plain towards the Balkan region including the 26th - 27th of August and the 1st and 2nd September. During these episode air masses passed over parts of Bosnia and Herzegovina, Southern Serbia, Albania and Macedonia. The verifying measurements at Skopje (Macedonia) show episodes of elevated Ambrosia pollen concentration the 26th -27th of August and for the 1st and 2nd of September. The model experiments with DEHM-Pollen strongly indicate that the Pannonian Plain alone can be a source to significant Ambrosia pollen concentrations in the Balkans. The methods and the model results look promising with respect to future numerical forecasting of Ambrosia

  5. Effect of tree species and end seal on attractiveness and utility of cut bolts to the redbay ambrosia beetle and granulate ambrosia beetle (coleoptera: Curculionidae: Scolytinae).

    PubMed

    Mayfield, A E; Hanula, J L

    2012-04-01

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is a non-native invasive pest and vector of the fungus that causes laurel wilt disease in certain trees of the family Lauraceae. This study assessed the relative attractiveness and suitability of cut bolts of several tree species to X. glabratus. In 2009, female X. glabratus were equally attracted to traps baited with swampbay (Persea palustris (Rafinesque) Sargent) and camphortree (Cinnamomum camphora (L.) J. Presl), which were more attractive than avocado (Persea americana Miller), lancewood (Ocotea coriacea (Swartz) Britton), and sweetbay (Magnolia virginiana L.). These species were more attractive than loblolly bay (Gordonia lasianthus (L.) J. Ellis). X. glabratus entrance hole density and emergence from caged bolts were highest on swampbay and camphortree. In 2010, swampbay was significantly more attractive to X. glabratus than sassafras (Sassafras albidum (Nuttall) Nees), yellow poplar (Liriodendron tulipifera L.), and eastern redbud (Cercis canadensis L.). Sassafras bolts end sealed with a liquid wax-and-water emulsion were more attractive to X. glabratus than end-sealed bolts of yellow poplar and redbud. Relative to unsealed bolts, end seal decreased X. glabratus entrance hole density on swampbay and decreased granulate ambrosia beetle (Xylosandrus crassiusculus (Motschulsky)) trap catch, entrance hole density, and adult emergence from swampbay. X. crassiusculus was not attracted to sassafras, yellow poplar, and redbud and was not more attracted to manuka oil than to unbaited traps. Sassafras was more attractive to X. glabratus than previously reported and supported reproducing populations of the insect. End sealing bolts with a wax-and-water emulsion may not be optimal for attracting and rearing ambrosia beetles in small logs. PMID:22606816

  6. Site observational work plan for the UMTRA Project site at Ambrosia Lake, New Mexico

    SciTech Connect

    Not Available

    1994-09-01

    The Ambrosia Lake Uranium Mill Tailings Remedial Action (UMTRA) Project site is within the Grants Mineral Belt and was one of numerous uranium mills supplied by many local mines. Ground water contamination at the site occurred as a result of uranium mill operations. The potential for impacts to human health and the environment from contaminated ground water currently does not exist. No domestic or livestock wells accessing ground water from the uppermost aquifer have been identified within a 5 mile radius from the site. Therefore, no current exposure pathways to humans, livestock, or wildlife exist, nor are any foreseen. The proposed ground water compliance strategy under consideration for application at the Ambrosia Lake site is to perform no remediation, based on the application of supplemental standards because the ground water has ``limited use.``

  7. Supplement to the UMTRA Project water sampling and analysis plan, Ambrosia Lake, New Mexico

    SciTech Connect

    1995-08-01

    The Ambrosia Lake Uranium Mill Tailings Remedial Action (UMTRA) Project site is in McKinley County, New Mexico. As part of UMTRA surface remediation, residual radioactive materials were consolidated on the site in a disposal cell that was completed July 1995. The need for ground water monitoring was evaluated and found not to be necessary beyond the completion of the remedial action because the ground water in the uppermost aquifer is classified as limited use.

  8. Site Observational Work Plan for the UMTRA project site at Ambrosia Lake, New Mexico

    SciTech Connect

    1995-02-01

    Ground water compliance for the Uranium Mill Tailings Remedial Action (UMTRA) Project sites, including the Ambrosia Lake, New Mexico, site, is governed by the Uranium Mills Tailings Radiation Control Act (42 USC {section}7901 et seq.) and the U.S. Environmental Protection Agency`s Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings (40 CFR Part 192; 60 FR 2854). The EPA standards describe specific conditions for which the U.S. Department of Energy (DOE) may apply for supplemental standards for contaminated ground water rather than meeting background levels or numerical standards. To achieve compliance with Subpart A of the EPA standards the residual radioactive materials are currently being consolidated on the site by the DOE in a disposal cell, isolating them from direct human or ecological contact and further dispersion into the environment. Completion of the disposal cell is scheduled for early 1995. An environmental assessment and a Finding of No Significant Impact (FONSI) were completed in 1987. Concurrence with the UMTRA Surface Project Ambrosia Lake remedial action plan (RAP) was granted by the U.S. Nuclear Regulatory Commission (NRC) and state of New Mexico in 1990. The DOE deferred compliance with Subpart B of the EPA standards in the Surface Project RAP. This site observational work plan (SOWP) is the first document to address ground water compliance under Subpart B at the Ambrosia Lake site. The Ambrosia Lake UMTRA Project site is within the Grants Mineral Belt and was one of numerous uranium mills supplied by many local mines. Ground water contamination at the site occurred as a result of uranium mill operations. Contamination of ground water resulted from discharge of waste water, infiltration of water through the tailings pile, hydraulic placement of mill tailings in nearby mines, and water pumped from mine shafts.

  9. The long distance transport of airborne Ambrosia pollen to the UK and the Netherlands from Central and south Europe

    NASA Astrophysics Data System (ADS)

    de Weger, Letty A.; Pashley, Catherine H.; Šikoparija, Branko; Skjøth, Carsten A.; Kasprzyk, Idalia; Grewling, Łukasz; Thibaudon, Michel; Magyar, Donat; Smith, Matt

    2016-04-01

    The invasive alien species Ambrosia artemisiifolia (common or short ragweed) is increasing its range in Europe. In the UK and the Netherlands, airborne concentrations of Ambrosia pollen are usually low. However, more than 30 Ambrosia pollen grains per cubic metre of air (above the level capable to trigger allergic symptoms) were recorded in Leicester (UK) and Leiden (NL) on 4 and 5 September 2014. The aims of this study were to determine whether the highly allergenic Ambrosia pollen recorded during the episode could be the result of long distance transport, to identify the potential sources of these pollen grains and to describe the conditions that facilitated this possible long distance transport. Airborne Ambrosia pollen data were collected at 10 sites in Europe. Back trajectory and atmospheric dispersion calculations were performed using HYSPLIT_4. Back trajectories calculated at Leicester and Leiden show that higher altitude air masses (1500 m) originated from source areas on the Pannonian Plain and Ukraine. During the episode, air masses veered to the west and passed over the Rhône Valley. Dispersion calculations showed that the atmospheric conditions were suitable for Ambrosia pollen released from the Pannonian Plain and the Rhône Valley to reach the higher levels and enter the airstream moving to northwest Europe where they were deposited at ground level and recorded by monitoring sites. The study indicates that the Ambrosia pollen grains recorded during the episode in Leicester and Leiden were probably not produced by local sources but transported long distances from potential source regions in east Europe, i.e. the Pannonian Plain and Ukraine, as well as the Rhône Valley in France.

  10. Effect of repetitive mowing on common ragweed (Ambrosia artemisiifolia L.) pollen and seed production.

    PubMed

    Simard, Marie-Josée; Benoit, Diane Lyse

    2011-01-01

    Ambrosia artemisiifolia L (common ragweed) is a familiar roadside weed in southern Québec (Canada) that produces large amounts of airborne pollen responsible for multiple rhino-conjunctivitis (hay fever) cases. As roadside weeds are increasingly controlled by mowing alone, the effect of a mowing treatment on pollen production was evaluated. Ambrosia artemisiifolia plants were grown in a greenhouse at 4 densities (1, 3, 6 and 12 plants per 314 cm(2) pot) and either left intact or mowed (10 cm from the ground) when the plants reached 25 cm in height, i.e. twice during the life cycle of this annual plant. Pollen production per male inflorescence was collected in open-top bags and counted. Inflorescence mass, length, location on the plant and date of anthesis onset was noted. Above-ground plant biomass and seed production was also evaluated. Mowed plants produced less pollen per unit of inflorescence length than intact plants. Pollen production per plant was reduced by a factor of 8.84 by the double mowing treatment, while viable seed production per plant was reduced by a factor of 4.66, irrespective of density. Mowing twice has the potential to reduce airborne pollen loads but Ambrosia artemisiifolia seed banks are unlikely to be depleted by this management strategy. PMID:21736270

  11. Plants remember past weather: a study for atmospheric pollen concentrations of Ambrosia, Poaceae and Populus

    NASA Astrophysics Data System (ADS)

    Matyasovszky, István; Makra, László; Csépe, Zoltán; Sümeghy, Zoltán; Deák, Áron József; Pál-Molnár, Elemér; Tusnády, Gábor

    2015-10-01

    After extreme dry (wet) summers or years, pollen production of different taxa may decrease (increase) substantially. Accordingly, studying effects of current and past meteorological conditions on current pollen concentrations for different taxa have of major importance. The purpose of this study is separating the weight of current and past weather conditions influencing current pollen productions of three taxa. Two procedures, namely multiple correlations and factor analysis with special transformation are used. The 11-year (1997-2007) data sets include daily pollen counts of Ambrosia (ragweed), Poaceae (grasses) and Populus (poplar), as well as daily values of four climate variables (temperature, relative humidity, global solar flux and precipitation). Multiple correlations of daily pollen counts with simultaneous values of daily meteorological variables do not show annual course for Ambrosia, but do show definite trends for Populus and Poaceae. Results received using the two methods revealed characteristic similarities. For all the three taxa, the continental rainfall peak and additional local showers in the growing season can strengthen the weight of the current meteorological elements. However, due to the precipitation, big amount of water can be stored in the soil contributing to the effect of the past climate elements during dry periods. Higher climate sensitivity (especially water sensitivity) of the herbaceous taxa ( Ambrosia and Poaceae) can be definitely established compared to the arboreal Populus. Separation of the weight of the current and past weather conditions for different taxa involves practical importance both for health care and agricultural production.

  12. Ambrosiella roeperi sp. nov. is the mycangial symbiont of the granulate ambrosia beetle, Xylosandrus crassiusculus.

    PubMed

    Harrington, Thomas C; McNew, Douglas; Mayers, Chase; Fraedrich, Stephen W; Reed, Sharon E

    2014-01-01

    Isolations from the granulate ambrosia beetle, Xylosandrus crassiusculus (Coleoptera: Curculionidae: Scolytinae: Xyleborini), collected in Georgia, South Carolina, Missouri and Ohio, yielded an undescribed species of Ambrosiella in thousands of colony-forming units (CFU) per individual female. Partial sequences of ITS and 28S rDNA regions distinguished this species from other Ambrosiella spp., which are asexual symbionts of ambrosia beetles and closely related to Ceratocystis spp. Ambrosiella roeperi sp. nov. produces sporodochia of branching conidiophores with disarticulating swollen cells, and the branches are terminated by thick-walled aleurioconidia, similar to the conidiophores and aleurioconidia of A. xylebori, which is the mycangial symbiont of a related ambrosia beetle, X. compactus. Microscopic examinations found homogeneous masses of arthrospore-like cells growing in the mycangium of X. crassiusculus, without evidence of other microbial growth. Using fungal-specific primers, only the ITS rDNA region of A. roeperi was amplified and sequenced from DNA extractions of mycangial contents, suggesting that it is the primary or only mycangial symbiont of this beetle in USA. PMID:24895423

  13. The occurrence of Ambrosia pollen in Rzeszów, Kraków and Poznań, Poland: investigation of trends and possible transport of Ambrosia pollen from Ukraine

    NASA Astrophysics Data System (ADS)

    Kasprzyk, Idalia; Myszkowska, Dorota; Grewling, Łukasz; Stach, Alicja; Šikoparija, Branko; Ambelas Skjøth, Carsten; Smith, Matt

    2011-07-01

    Previous studies have shown that ragweed pollen arrives in Poland from sources in the south, in Slovakia, the Czech Republic, Hungary and Austria. It is likely that ragweed pollen also arrives from sources in the southeast (e.g. Ukraine). This hypothesis was investigated using 13 years of pollen data and back-trajectory analysis. Ambrosia pollen data were collected at three sites in Poland, Rzeszów, Kraków and Poznań. The amount of ragweed pollen recorded at Rzeszów was significantly higher than in Poznań and Kraków. This can be related to either a higher abundance of local populations of Ambrosia in south-east Poland or the proximity of Rzeszów to foreign sources of ragweed pollen. The combined results of pollen measurements and air mass trajectory calculations identified plumes of Ambrosia pollen that were recorded at Rzeszów, Kraków and Poznań on 4 and 5 September 1999 and 3 September 2002. These plumes arrived at the pollen-monitoring sites from an easterly direction, indicating sources of Ambrosia pollen in eastern Poland or Ukraine. This identifies Ukraine as a possible new source of ragweed pollen for Poland and therefore an important source area of Ambrosia pollen on the European Continent.

  14. An inordinate fondness for Fusarium: Phylogenetic diversity of fusaria cultivated by ambrosia beetles in the genus Euwallacea on avocado and other plant hosts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ambrosia beetle fungiculture represents one of the most ecologically and evolutionarily successful symbioses, as evidenced by the spectacular adaptive radiation that gave rise to at least 3,500 extant Xyleborini. Here we document the evolution of a clade within Fusarium associated with ambrosia beet...

  15. The ambrosia symbiosis is specific in some species and promiscuous in others: evidence from community pyrosequencing

    PubMed Central

    Kostovcik, Martin; Bateman, Craig C; Kolarik, Miroslav; Stelinski, Lukasz L; Jordal, Bjarte H; Hulcr, Jiri

    2015-01-01

    Symbioses are increasingly seen as dynamic ecosystems with multiple associates and varying fidelity. Symbiont specificity remains elusive in one of the most ecologically successful and economically damaging eukaryotic symbioses: the ambrosia symbiosis of wood-boring beetles and fungi. We used multiplexed pyrosequencing of amplified internal transcribed spacer II (ITS2) ribosomal DNA (rDNA) libraries to document the communities of fungal associates and symbionts inside the mycangia (fungus transfer organ) of three ambrosia beetle species, Xyleborus affinis, Xyleborus ferrugineus and Xylosandrus crassiusculus. We processed 93 beetle samples from 5 locations across Florida, including reference communities. Fungal communities within mycangia included 14–20 fungus species, many more than reported by culture-based studies. We recovered previously known nutritional symbionts as members of the core community. We also detected several other fungal taxa that are equally frequent but whose function is unknown and many other transient species. The composition of fungal assemblages was significantly correlated with beetle species but not with locality. The type of mycangium appears to determine specificity: two Xyleborus with mandibular mycangia had multiple dominant associates with even abundances; Xylosandrus crassiusculus (mesonotal mycangium) communities were dominated by a single symbiont, Ambrosiella sp. Beetle mycangia also carried many fungi from the environment, including plant pathogens and endophytes. The ITS2 marker proved useful for ecological analyses, but the taxonomic resolution was limited to fungal genus or family, particularly in Ophiostomatales, which are under-represented in our amplicons as well as in public databases. This initial analysis of three beetle species suggests that each clade of ambrosia beetles and each mycangium type may support a functionally and taxonomically distinct symbiosis. PMID:25083930

  16. The ambrosia symbiosis is specific in some species and promiscuous in others: evidence from community pyrosequencing.

    PubMed

    Kostovcik, Martin; Bateman, Craig C; Kolarik, Miroslav; Stelinski, Lukasz L; Jordal, Bjarte H; Hulcr, Jiri

    2015-01-01

    Symbioses are increasingly seen as dynamic ecosystems with multiple associates and varying fidelity. Symbiont specificity remains elusive in one of the most ecologically successful and economically damaging eukaryotic symbioses: the ambrosia symbiosis of wood-boring beetles and fungi. We used multiplexed pyrosequencing of amplified internal transcribed spacer II (ITS2) ribosomal DNA (rDNA) libraries to document the communities of fungal associates and symbionts inside the mycangia (fungus transfer organ) of three ambrosia beetle species, Xyleborus affinis, Xyleborus ferrugineus and Xylosandrus crassiusculus. We processed 93 beetle samples from 5 locations across Florida, including reference communities. Fungal communities within mycangia included 14-20 fungus species, many more than reported by culture-based studies. We recovered previously known nutritional symbionts as members of the core community. We also detected several other fungal taxa that are equally frequent but whose function is unknown and many other transient species. The composition of fungal assemblages was significantly correlated with beetle species but not with locality. The type of mycangium appears to determine specificity: two Xyleborus with mandibular mycangia had multiple dominant associates with even abundances; Xylosandrus crassiusculus (mesonotal mycangium) communities were dominated by a single symbiont, Ambrosiella sp. Beetle mycangia also carried many fungi from the environment, including plant pathogens and endophytes. The ITS2 marker proved useful for ecological analyses, but the taxonomic resolution was limited to fungal genus or family, particularly in Ophiostomatales, which are under-represented in our amplicons as well as in public databases. This initial analysis of three beetle species suggests that each clade of ambrosia beetles and each mycangium type may support a functionally and taxonomically distinct symbiosis. PMID:25083930

  17. Immunoproteomic characterization of Ambrosia artemisiifolia pollen allergens in canine atopic dermatitis.

    PubMed

    Ognjenovic, Jana; Milcic-Matic, Natalija; Smiljanic, Katarina; Vuckovic, Olga; Burazer, Lidija; Popovic, Nikola; Stanic-Vucinic, Dragana; Velickovic, Tanja Cirkovic

    2013-09-01

    Canine atopic dermatitis (CAD) is an immune system disorder that affects 10-15% of the canine population. Short ragweed (Ambrosia artemisiifolia) pollen represents one of the major seasonal sources of allergenic pollen proteins in Europe, particularly in the Pannonian valley of the Balkan region. In Serbia, about 66% of atopic dogs showed a positive intradermal skin test with its pollen extract, which is second to house dust mites. Therefore, characterization of Ambrosia artemisiifolia pollen components, in terms of defining major and minor allergens that induce clinically manifested allergic reaction in dogs, is important for valid diagnosis and efficient therapy. This study has, for the first time, characterized and identified major Ambrosia artemisiifolia allergens in CAD, using an immunoproteomic approach. To assess the prevalence of specific IgE in electrophoretically separated ragweed pollen proteins, individual reactivity of sera from dogs with CAD was analyzed and compared to the reactivity of sera from healthy dogs in the non-reducing conditions, which were found optimal for specific canine IgE detection. A specific IgE band (38 kDa) was recognized as the most dominant allergen in CAD, occurring in 81% of positive dog's sera. 2-D immunoblotting followed by a mass spectrometry peptide fingerprint analyses with pooled canine and human atopic sera, revealed that 38 kDa major Ambrosia atremisiifolia allergens in CAD were all five isoallergens of the Amb a 1 group (antigen E), including the previously named Amb a 2 (antigen K). In contrast to canine sera, human atopic sera also recognized lower mass allergens such as the β fragment of Amb a 1 and profilins (Amb a 8 variants). The most prominent ragweed proteins in CAD, represent, as in humans, variants of all five isoallergens of the Amb a 1 group (pectate lyase): Amb a 1.0101 and its natural variant E1XUL2, Amb a 1.0202, 1.0304, 1.0402 and the natural variant of Amb a 1.0501, E1XUM0, as well as the

  18. Long-term surveillance plan for the Ambrosia Lake, New Mexico disposal site

    SciTech Connect

    1995-11-01

    This long-term surveillance plan (LTSP) for the Uranium Mill Tailings Remedial Action (UMTRA) Project Ambrosia Lake disposal site in McKinley County, New Mexico, describes the US Department of Energy`s (DOE) long-term care program for the disposal site. The DOE will carry out this program to ensure that the disposal cell continues to function as designed. This LTSP was prepared as a requirement for acceptance under the US Nuclear Regulatory Commission (NRC) general license for custody and long-term care of residual radioactive materials.

  19. Long-term surveillance plan for the Ambrosia Lake, New Mexico disposal site

    SciTech Connect

    1996-07-01

    This long-term surveillance plan (LTSP) for the Uranium Mill Tailings Remedial Action (UMTRA) Project Ambrosia Lake disposal site in McKinley County, New Mexico, describes the U.S. Department of Energy`s (DOE) long-term care program for the disposal site. The DOE will carry out this program to ensure that the disposal cell continues to function as designed. This LTSP was prepared as a requirement for acceptance under the U.S. Nuclear Regulatory Commission (NRC) general license for custody and long-term care of residual radioactive materials.

  20. Effects of elevated co2 on biomass and fungi associated with two ecotypes of ragweed (Ambrosia artemisiifolia L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide resistant weed populations have developed due to the repeated application of herbicides. Elevated concentrations of atmospheric CO2 can have positive effects on weed growth, but how rising CO2 might affect herbicide resistant weeds is not known. Ragweed (Ambrosia artemisiifolia L.) ecotype...

  1. Enrichment of alpha-copaene content results in improved lure for redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The exotic redbay ambrosia beetle, Xyleborus glabratus Eichhoff, has become a serious invasive pest in the USA, now established in seven southeastern states. Females are the primary vectors of a fungal pathogen, Raffaelea lauricola, that causes laurel wilt. This vascular disease has caused extensi...

  2. The invasive ambrosia beetle Euwallacea fornicates vectors an exotic symbiotic Fusarium species that threatens avocado production in Israel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The invasive ambrosia beetle (Euwallacea fornicatus Eichhoff) was first recorded in Israel in 2009, and it has been shown to vector an exotic fusarial pathogen. Multilocus molecular phylogenetic analyses indicate that the pathogen represents a novel symbiotic Fusarium sp. within Clade 3 of the Fusar...

  3. Redbay ambrosia beetle/Laurel wilt: Overview of projects at the USDA-ARS Subtropical Horticulture Research Station

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ABSTRACT Laurel wilt, a deadly fungal disease of avocado and other trees in the Lauraceae, is vectored by the redbay ambrosia beetle (Xyleborus glabratus). First detected near Savannah, GA in 2002, the beetle and its obligatory pathogen have since spread to South Carolina and Florida. Currently, t...

  4. Effects of elevated CO2 on biomass and fungi associated with two ecotypes of ragweed (Ambrosia artemisiifolia L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide resistant weed populations have developed due to the repeated application of herbicides. Elevated concentrations of atmospheric CO2 can have positive effects on weed growth, but how rising CO2 might affect herbicide resistant weeds is not known. Ragweed (Ambrosia artemisiifolia L.) ecotype...

  5. Characterization and host range of the symbiotic fungus Fusarium euwallaceae sp. nov., vectored by the invasive ambrosia beetle Euwallacea sp.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel symbiotic Fusarium euwallaceae fungus that serves as a specific nutritional source for the invasive Asian ambrosia beetle Euwallacea sp. (Coleoptera, Scolytinae, Xyleborini) is farmed in the galleries of host plants. This beetle-fungus complex, which has invaded Israel and California, is clo...

  6. Monitoring Ambrosia Beetles with Ethanol-Injected Sentinel Trees and Ethanol-Baited Bottle Traps in Ornamental Nurseries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ambrosia beetle Xylosandrus germanus is a serious pest in ornamental tree nurseries. The current strategy for managing X. germanus in nurseries is to spray the trunks of trees with insecticides before damage occurs. However, timing sprays for this pest is difficult because monitoring technique...

  7. Flood stress as a technicque to assess preventive insecticide and fungicide treatments for protecting trees against ambrosia beetles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The exotic ambrosia beetles Xylosandrus germanus, Xylosandrus crassiusculus, and Xylosandrus compactus tunnel into the heartwood of trees where they cultivate and feed upon a symbiotic fungus. We assessed the effectiveness of flood stress as a tactic for making trees attractive and vulnerable to att...

  8. Fusarium euwallaceae, a novel species cultivated by a Euwallacea ambrosia beetle that threatens avocado production in Israel and California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avocado production in Israel and California, USA is facing a serious threat due to damage caused by an invasive Euwallacea ambrosia beetle and a novel Fusarium that it cultivates as a source of food. Adult female beetles possess mandibular mycangia within which they carry the Fusarium symbiont. At l...

  9. Fusarium symbionts of an ambrosia beetle (Euwallacea sp.) in southern Florida are pathogens of avocado, Persea americana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium dieback, a destructive disease of avocado (Persea americana), was reported in California and Israel in 2012. It is associated with an ambrosia beetle, Euwallacea sp., and damage caused by an unnamed symbiont of the beetle in Clade 3 of the Fusarium solani species complex (FSSC) designated p...

  10. Is California bay laurel a suitable host for the non-native redbay ambrosia beetle, vector of laurel wilt disease?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laurel wilt is a deadly vascular disease of trees in the Lauraceae that kills healthy redbay (Persea borbonia), sassafras (Sassafras albidum), and other related hosts. The fungal pathogen (Raffaelea lauricola) and it vector, the redbay ambrosia beetle (Xyleborus glabratus) are native to Asia and ha...

  11. Cubeb oil Lures: sesquiterpene emissions and efficacy for attraction of redbay ambrosia beetle, Xyleborus glabratus(Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle (RAB), Xyleborus glabratus, is an exotic wood-boring pest that vectors Raffaelea lauricola, a symbiotic fungus that causes laurel wilt. This lethal disease has decimated native redbay (Persea borbonia) and swampbay (P. palustris) trees throughout the southeastern U.S., and...

  12. Cubeb oil lures:terpenoid emissions, trapping efficacy, and longevity for attraction of redbay ambrosia beetle (Coleoptera:Curculionidae:Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-borer and the primary vector of Raffaelea lauricola, a symbiotic fungus that causes laurel wilt. This lethal disease has decimated native redbay (Persea borbonia) and swampbay (P. palustris) throughout southeastern U.S. forests, and curr...

  13. North American Lauraceae: Terpenoid emissions, relative attraction and boring preferences of redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The invasive redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of Raffaelea lauricola, a symbiotic fungus and the etiologic agent of laurel wilt. This lethal disease has caused severe mortality of redbay (Persea borbonia) and swampbay (P. palustris) trees in the southeastern USA, t...

  14. A pernicious agent affecting avocado in Israel: a novel symbiotic Fusarium sp. associated with the ambrosia beetle Euwallacea fornicatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since first recorded in Israel in 2009, the ambrosia beetle, Euwallacea fornicatus Eichhoff, has been shown to vector a fusarial pathogen of avocado (Persea Americana Miller) in its mandibular mycangia. Multilocus molecular phylogenetic analyses indicate the pathogen represents a novel symbiotic Fus...

  15. Fusarium euwallaceae sp. nov.—a symbiotic fungus of Euwallacea sp., an invasive ambrosia beetle in Israel and California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The invasive Asian ambrosia beetle Euwallacea sp. (Coleoptera, Scolytinae, Xyleborini) and a novel Fusarium sp. that it farms in its galleries as a source of nutrition seriously damage over 20 species of live trees and pose a serious threat to avocado production (Persea americana) in Israel and Cali...

  16. Efficacy and longevity of essential oil lures for capture of the redbay ambrosia beetle Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle Xyleborus glabratus Eichhoff is an exotic wood-boring pest native to southeastern Asia. It carries a symbiotic fungus (Raffaelea lauricola) that causes laurel wilt, a lethal vascular disease of trees in the Lauraceae. First detected in Georgia in 2002, the beetle has spre...

  17. Environmental Factors That Influence a Mutualism Between the Earthworm Lumbricus terrestris L. and the Annual Weed Ambrosia trifida L.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The earthworm Lumbricus terrestris L. can improve Ambrosia trifida L. seed survival and seedling recruitment in agroecosystems with high risks of post-dispersal seed predation. In a previous 1-yr survey of no-till agricultural fields in the eastern U.S. Corn Belt, both L. terrestris and A. trifida w...

  18. Susceptibility of Persea spp. and other Lauraceae to attack by redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Redbay ambrosia beetle (RAB), Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), a native of Asia, was first discovered in the U.S. near Savannah, Georgia in 2002. RAB is an effective vector of Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva that causes laurel wilt (LW), a l...

  19. Carbon isotopic composition of Ambrosia and Artemisia pollen: assessment of a C₃-plant paleophysiological indicator.

    PubMed

    Nelson, David M

    2012-09-01

    There is limited evidence on how shifts in plant physiological performance influence vegetation variations in the paleorecord. To evaluate δ¹³C of pollen from C₃ plants as an indicator of community-level physiology, small quantities (10-30 grains) of untreated pollen and sporopollenin from herbarium specimens of Ambrosia (A. tomentosa and A. psilostachya) and Artemisia (A. frigida, A. ludoviciana and A. dracunculus), genera abundant in grassland pollen profiles, were isolated by micromanipulation. Their δ¹³C values were measured using a spooling-wire microcombustion device interfaced with an isotope-ratio mass spectrometer. Leaf δ¹³C was also measured. Carbon isotope discrimination (Δ) for untreated pollen, sporopollenin and leaves was compared with historic records of seasonal precipitation amount, vapor pressure deficit and the Palmer Drought Severity Index (PDSI). Each species showed positive correlations between Δ of untreated pollen and sporopollenin. Sporopollenin Δ was most strongly correlated with PDSI. Correlations among leaf Δ and moisture indicators were stronger for Ambrosia than Artemisia. These results suggest that sporopollenin Δ indicates the level of moisture stress in C₃ plants. Therefore, δ¹³C analysis of pollen promises to help address important paleoecological questions, such as how community-level physiology contributes to shifts in vegetation composition. PMID:22742492

  20. UMTRA project water sampling and analysis plan, Ambrosia Lake, New Mexico

    SciTech Connect

    Not Available

    1994-02-01

    This water sampling and analysis plan (WSAP) provides the basis for ground water sampling at the Ambrosia Lake Uranium Mill Tailings Remedial Action (UMTRA) Project site during fiscal year 1994. It identifies and justifies the sampling locations, analytical parameters, detection limits, and sampling frequency for the monitoring locations and will be updated annually. The Ambrosia Lake site is in McKinley County, New Mexico, about 40 kilometers (km) (25 miles [mi]) north of Grants, New Mexico, and 1.6 km (1 mi) east of New Mexico Highway 509 (Figure 1.1). The town closest to the tailings pile is San Mateo, about 16 km ( 10 mi) southeast (Figure 1.2). The former mill and tailings pile are in Section 28, and two holding ponds are in Section 33, Township 14 North, Range 9 West. The site is shown on the US Geological Survey (USGS) map (USGS, 1980). The site is approximately 2100 meters (m) (7000 feet [ft]) above sea level.

  1. Ambrosia Beetle (Coleoptera: Scolytidae) Species, Flight, and Attack on Living Eastern Cottonwood Trees.

    SciTech Connect

    Coyle, D R; D.C. Booth: M.S. Wallace

    2005-12-01

    ABSTRACT In spring 2002, ambrosia beetles (Coleoptera: Scolytidae) infested an intensively managed 22-ha tree plantation on the upper coastal plain of South Carolina. Nearly 3,500 scolytids representing 28 species were captured in ethanol-baited traps from 18 June 2002 to 18 April 2004. More than 88% of total captures were exotic species. Five species [Dryoxylon onoharaensum (Murayama), Euwallacea validus (Eichhoff), Pseudopityophthorus minutissimus (Zimmermann), Xyleborus atratus Eichhoff, and Xyleborus impressus Eichhoff]) were collected in South Carolina for the first time. Of four tree species in the plantation, eastern cottonwood, Populus deltoides Bartram, was the only one attacked, with nearly 40% of the trees sustaining ambrosia beetle damage. Clone ST66 sustained more damage than clone S7C15. ST66 trees receiving fertilization were attacked more frequently than trees receiving irrigation, irrigation_fertilization, or controls, although the number of S7C15 trees attacked did not differ among treatments. The study location is near major shipping ports; our results demonstrate the necessity for intensive monitoring programs to determine the arrival, spread, ecology, and impact of exotic scolytids.

  2. Roots Revisited.

    ERIC Educational Resources Information Center

    Hughes, Barnabas

    1998-01-01

    Offers historical information about square roots. Presents three different methods--Hero's method, visual method, and remainder method--which can be used to teach the finding of square roots and one method for determining cube roots. (ASK)

  3. Molecular characterization of atrazine resistance in common ragweed (Ambrosia artemisiifolia L.).

    PubMed

    Cseh, A; Cernak, I; Taller, J

    2009-01-01

    Common ragweed (Ambrosia artemisiifolia L.) is the most frequent weed in the Carpathian Basin and is spreading fast in other parts of Europe. In recent years, besides the wild type, a mutant genotype resistant to atrazine herbicides has evolved and is now widespread in many areas. The present study demonstrates that the atrazine resistance of ragweed is maternally inherited, and is caused by a point mutation in the psbA chloroplast gene. The promoter 5'-untranslated region and the open reading frame regions of the gene were analysed, and a homology search was performed. Both the atrazine-resistant and susceptible types of cpDNA were present in atrazine-resistant plants, while the mixed presence of both genotypes in the same plant, known as heteroplasmy, was not unequivocally detectable in susceptible plants. PMID:19875882

  4. Genetic differentiation in life-history traits of introduced and native common ragweed (Ambrosia artemisiifolia) populations.

    PubMed

    Hodgins, K A; Rieseberg, L

    2011-12-01

    Introduced species represent opportunities to observe evolution over contemporary time scales, and as exotics encounter new environments, adaptive responses can occur, potentially contributing to invasion. Here, we compare 22 native North American populations and 12 introduced European populations of common ragweed (Ambrosia artemisiifolia) in five common gardens (control, herbivory, light stress, nutrient stress and drought). We found evidence for improved growth and reproduction of the introduced populations in most environments, particularly in the light stress. However, under drought conditions, the introduced plants experienced more rapid wilting and mortality than their native counterparts, evidence consistent with a life-history trade-off between rapid growth and drought tolerance. Moreover, we found parallel latitudinal clines in flowering time and correlations between fitness components and the local climate of the source populations in both ranges. Together these data provide evidence for adaptation to local environmental conditions in the native and introduced range of common ragweed. PMID:22023052

  5. 3-pentanol: a new attractant present in volatile emissions from the ambrosia beetle, Megaplatypus mutatus.

    PubMed

    Gatti Liguori, Pablo; Zerba, Eduardo; Alzogaray, Raul A; Gonzalez Audino, Paola

    2008-11-01

    Megaplatypus mutatus (=Platypus mutatus) (Coleoptera: Platypodidae) is an ambrosia beetle that is native to South America. It attacks only standing live trees and causes severe stem breakage and death in commercial poplar (Populus) plantations. Previous work showed that male M. mutatus emits a sex pheromone composed mainly of (+)-sulcatol and sulcatone. We collected male volatile emissions during the hours of maximum emergence by using a specific polar microextraction phase; analyzed the extract by GC-MS; and tested the biological activity of selected compounds in the extract with a walking behavioral assay. Female M. mutatus emerged primarily between 7 and 11 h. In the chemical analyses of volatiles, a third compound, 3-pentanol, was identified in a small percentage of samples. Walking behavioral bioassays with video image analysis showed that at the doses tested, 3-pentanol elicited an attractive response from females. PMID:18850328

  6. Chemical composition and antimicrobial activity of the essential oil from Ambrosia trifida L.

    PubMed

    Wang, Peng; Kong, Chui Hua; Zhang, Chao Xian

    2006-01-01

    The essential oil obtained by steam distillation of dried aerial parts of Ambrosia trifida L. from Northeast China was analyzed by GC and GC-MS. The essential oil yield based on dried plant material was 0.12% and thirty-five compounds (corresponding to 86.7% of the total weight) were identified. The main components were: bornyl acetate (15.5%), borneol (8.5%), caryophyllene oxide (8.3%), alpha-pinene (8.0%), germacrene D (6.3%), beta-caryophyllene (4.6%), trans-carveol (2.9%), beta-myrcene (2.6%), camphor (2.4%) and limonene (3.2%). A. trifida essential oil demonstrated bactericidal and fungicidal activity against six bacterial strains and two fungal strains, using the agar diffusion method. PMID:17971726

  7. Ragweed pollen source inventory for France - The second largest centre of Ambrosia in Europe

    NASA Astrophysics Data System (ADS)

    Thibaudon, Michel; Šikoparija, Branko; Oliver, Gilles; Smith, Matt; Skjøth, Carsten A.

    2014-02-01

    France, in particular the Rhône-Alpes region, is one of the three main centres of ragweed (Ambrosia) in Europe. The aim of this study is to develop a gridded ragweed pollen source inventory for all of France that can be used in assessments, eradication plans and by atmospheric models for describing concentrations of airborne ragweed pollen. The inventory combines information about spatial variations in annual Ambrosia pollen counts, knowledge of ragweed ecology, detailed land cover information and a Digital Elevation Model. The ragweed inventory consists of a local infection level on a scale of 0-100% (where 100% is the highest plant abundance per area in the studied region) and a European infection level between 0% and 100% (where 100% relates to the highest identified plant abundance in Europe using the same methodology) that has been distributed onto the EMEP grid with 5 km × 5 km resolution. The results of this analysis showed that some of the highest mean annual ragweed pollen concentrations were recorded at Roussillon in the Rhône-Valley. This is reflected by the inventory, where the European infection level has been estimated to reach 67.70% of the most infected areas in Europe i.e. Kecskemét in central Hungary. The inventory shows that the Rhône Valley is the most heavily infected part of France. Central France is also infected, but northern and western parts of France are much less infected. The inventory can be entered into atmospheric transport models, in combination with other components such as a phenological model and a model for daily pollen release, in order to simulate the dispersion of ragweed pollen within France as well as potential long-distance transport from France to other European countries.

  8. Non-Native Ambrosia Beetles as Opportunistic Exploiters of Living but Weakened Trees

    PubMed Central

    Ranger, Christopher M.; Schultz, Peter B.; Frank, Steven D.; Chong, Juang H.; Reding, Michael E.

    2015-01-01

    Exotic Xylosandrus spp. ambrosia beetles established in non-native habitats have been associated with sudden and extensive attacks on a diverse range of living trees, but factors driving their shift from dying/dead hosts to living and healthy ones are not well understood. We sought to characterize the role of host physiological condition on preference and colonization by two invaders, Xylosandrus germanus and Xylosandrus crassiusculus. When given free-choice under field conditions among flooded and non-flooded deciduous tree species of varying intolerance to flooding, beetles attacked flood-intolerant tree species over more tolerant species within 3 days of initiating flood stress. In particular, flood-intolerant flowering dogwood (Cornus florida) sustained more attacks than flood-tolerant species, including silver maple (Acer saccharinum) and swamp white oak (Quercus bicolor). Ethanol, a key host-derived attractant, was detected at higher concentrations 3 days after initiating flooding within stems of flood intolerant species compared to tolerant and non-flooded species. A positive correlation was also detected between ethanol concentrations in stem tissue and cumulative ambrosia beetle attacks. When adult X. germanus and X. crassiusculus were confined with no-choice to stems of flood-stressed and non-flooded C. florida, more ejected sawdust resulting from tunneling activity was associated with the flood-stressed trees. Furthermore, living foundresses, eggs, larvae, and pupae were only detected within galleries created in stems of flood-stressed trees. Despite a capability to attack diverse tree genera, X. germanus and X. crassiusculus efficiently distinguished among varying host qualities and preferentially targeted trees based on their intolerance of flood stress. Non-flooded trees were not preferred or successfully colonized. This study demonstrates the host-selection strategy exhibited by X. germanus and X. crassiusculus in non-native habitats involves

  9. Composition of polyphenol and polyamide compounds in common ragweed (Ambrosia artemisiifolia L.) pollen and sub-pollen particles.

    PubMed

    Mihajlovic, Luka; Radosavljevic, Jelena; Burazer, Lidija; Smiljanic, Katarina; Cirkovic Velickovic, Tanja

    2015-01-01

    Phenolic composition of Ambrosia artemisiifolia L. pollen and sub-pollen particles (SPP) aqueous extracts was determined, using a novel extraction procedure. Total phenolic and flavonoid content was determined, as well as the antioxidative properties of the extract. Main components of water-soluble pollen phenolics are monoglycosides and malonyl-mono- and diglycosides of isorhamnetin, quercetin and kaempferol, while spermidine derivatives were identified as the dominant polyamides. SPP are similar in composition to pollen phenolics (predominant isorhamnetin and quercetin monoglycosides), but lacking small phenolic molecules (<450Da). Ethanol-based extraction protocol revealed one-third lower amount of total phenolics in SPP than in pollen. For the first time in any pollen species, SPP and pollen phenolic compositions were compared in detail, with an UHPLC/ESI-LTQ-Orbitrap-MS-MS approach, revealing the presence of spermidine derivatives in both SPP and pollen, not previously reported in Ambrosia species. PMID:25468540

  10. Two newly introduced tropical bark and ambrosia beetles (Coleoptera: Curculionidae, Scolytinae) damaging figs (Ficus carica) in southern Italy.

    PubMed

    Faccoli, Massimo; Campo, Giuseppe; Perrotta, Giancarlo; Rassati, Davide

    2016-01-01

    In summer 2014, the bark beetle Hypocryphalus scabricollis (Eichhoff) and the ambrosia beetle Xyleborus bispinatus Eichhoff, species new to Italy and Europe, respectively, were found for the first time in south-eastern Sicily (Italy). Large infestations of the two species were recorded in many plantations of common fig (Ficus carica L.) both in 2014 and 2015. Data concerning insect characteristics, taxonomy, and distribution are briefly reported. PMID:27470760

  11. Simple and Efficient Trap for Bark and Ambrosia Beetles (Coleoptera: Curculionidae) to Facilitate Invasive Species Monitoring and Citizen Involvement.

    PubMed

    Steininger, M S; Hulcr, J; Šigut, M; Lucky, A

    2015-06-01

    Bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae & Platypodinae) are among the most damaging forest pests worldwide, and monitoring is essential to damage prevention. Unfortunately, traps and attractants that are currently used are costly, and agencies rely on limited field personnel for deployment. The situation can be greatly aided by 1) the development of cost-effective trapping techniques, and 2) distribution of the effort through the Citizen Science approach. The goal of this study was to test a simple, effective trap that can be made and deployed by anyone interested in collecting bark and ambrosia beetles. Three trap types made from 2-liter soda bottles and, separately, four attractants were compared. Simple, one-window traps performed comparably at capturing species in traps painted or with multiple windows. A comparison of attractants in two-window traps found that 95% ethanol attracted the highest number of species but that Purell hand sanitizer (70% ethanol) and then Germ-X hand sanitizer (63% ethanol) were also effective. A perforated zip-top plastic bag containing Purell hanging over a trap filled with automobile antifreeze attracted the fewest species and individual specimens. Overall, >4,500 bark and ambrosia beetles, including 30 species were captured, representing a third of the regional species diversity. More than three quarters of the specimens were nonnative, representing nearly half of the known regional exotic species. These results suggest that simple one-window soda bottle traps baited with ethanol-based hand sanitizer will be effective and inexpensive tools for large-scale monitoring of bark and ambrosia beetles. PMID:26470236

  12. New Fungus-Insect Symbiosis: Culturing, Molecular, and Histological Methods Determine Saprophytic Polyporales Mutualists of Ambrosiodmus Ambrosia Beetles.

    PubMed

    Li, You; You, Li; Simmons, David Rabern; Bateman, Craig C; Short, Dylan P G; Kasson, Matthew T; Rabaglia, Robert J; Hulcr, Jiri

    2015-01-01

    Ambrosia symbiosis is an obligate, farming-like mutualism between wood-boring beetles and fungi. It evolved at least 11 times and includes many notorious invasive pests. All ambrosia beetles studied to date cultivate ascomycotan fungi: early colonizers of recently killed trees with poor wood digestion. Beetles in the widespread genus Ambrosiodmus, however, colonize decayed wood. We characterized the mycosymbionts of three Ambrosiodmus species using quantitative culturing, high-throughput metabarcoding, and histology. We determined the fungi to be within the Polyporales, closely related to Flavodon flavus. Culture-independent sequencing of Ambrosiodmus minor mycangia revealed a single operational taxonomic unit identical to the sequences from the cultured Flavodon. Histological sectioning confirmed that Ambrosiodmus possessed preoral mycangia containing dimitic hyphae similar to cultured F. cf. flavus. The Ambrosiodmus-Flavodon symbiosis is unique in several aspects: it is the first reported association between an ambrosia beetle and a basidiomycotan fungus; the mycosymbiont grows as hyphae in the mycangia, not as budding pseudo-mycelium; and the mycosymbiont is a white-rot saprophyte rather than an early colonizer: a previously undocumented wood borer niche. Few fungi are capable of turning rotten wood into complete animal nutrition. Several thousand beetle-fungus symbioses remain unstudied and promise unknown and unexpected mycological diversity and enzymatic innovations. PMID:26367271

  13. New Fungus-Insect Symbiosis: Culturing, Molecular, and Histological Methods Determine Saprophytic Polyporales Mutualists of Ambrosiodmus Ambrosia Beetles

    PubMed Central

    Bateman, Craig C.; Short, Dylan P. G.; Kasson, Matthew T.; Rabaglia, Robert J.; Hulcr, Jiri

    2015-01-01

    Ambrosia symbiosis is an obligate, farming-like mutualism between wood-boring beetles and fungi. It evolved at least 11 times and includes many notorious invasive pests. All ambrosia beetles studied to date cultivate ascomycotan fungi: early colonizers of recently killed trees with poor wood digestion. Beetles in the widespread genus Ambrosiodmus, however, colonize decayed wood. We characterized the mycosymbionts of three Ambrosiodmus species using quantitative culturing, high-throughput metabarcoding, and histology. We determined the fungi to be within the Polyporales, closely related to Flavodon flavus. Culture-independent sequencing of Ambrosiodmus minor mycangia revealed a single operational taxonomic unit identical to the sequences from the cultured Flavodon. Histological sectioning confirmed that Ambrosiodmus possessed preoral mycangia containing dimitic hyphae similar to cultured F. cf. flavus. The Ambrosiodmus-Flavodon symbiosis is unique in several aspects: it is the first reported association between an ambrosia beetle and a basidiomycotan fungus; the mycosymbiont grows as hyphae in the mycangia, not as budding pseudo-mycelium; and the mycosymbiont is a white-rot saprophyte rather than an early colonizer: a previously undocumented wood borer niche. Few fungi are capable of turning rotten wood into complete animal nutrition. Several thousand beetle-fungus symbioses remain unstudied and promise unknown and unexpected mycological diversity and enzymatic innovations. PMID:26367271

  14. Square Root +

    ERIC Educational Resources Information Center

    Frederiksen, John G.

    1969-01-01

    A rational presentation of the so-called long division method for extracting the square root of a number. Diagrams are used to show relationship of this technique to the binomial theorem. Presentation exposes student to many facets of mathematics in addition to the mechanics of funding square root and cube root. Geometry, algebraic statements,…

  15. Discordant phylogenies suggest repeated host shifts in the Fusarium-Euwallacea ambrosia beetle mutualism.

    PubMed

    O'Donnell, Kerry; Sink, Stacy; Libeskind-Hadas, Ran; Hulcr, Jiri; Kasson, Matthew T; Ploetz, Randy C; Konkol, Joshua L; Ploetz, Jill N; Carrillo, Daniel; Campbell, Alina; Duncan, Rita E; Liyanage, Pradeepa N H; Eskalen, Akif; Na, Francis; Geiser, David M; Bateman, Craig; Freeman, Stanley; Mendel, Zvi; Sharon, Michal; Aoki, Takayuki; Cossé, Allard A; Rooney, Alejandro P

    2015-09-01

    The mutualism between xyleborine beetles in the genus Euwallacea (Coleoptera: Curculionidae: Scolytinae) and members of the Ambrosia Fusarium Clade (AFC) represents one of 11 known evolutionary origins of fungiculture by ambrosia beetles. Female Euwallacea beetles transport fusarial symbionts in paired mandibular mycangia from their natal gallery to woody hosts where they are cultivated in galleries as a source of food. Native to Asia, several exotic Euwallacea species were introduced into the United States and Israel within the past two decades and they now threaten urban landscapes, forests and avocado production. To assess species limits and to date the evolutionary diversification of the mutualists, we reconstructed the evolutionary histories of key representatives of the Fusarium and Euwallacea clades using maximum parsimony and maximum likelihood methods. Twelve species-level lineages, termed AF 1-12, were identified within the monophyletic AFC and seven among the Fusarium-farming Euwallacea. Bayesian diversification-time estimates placed the origin of the Euwallacea-Fusarium mutualism near the Oligocene-Miocene boundary ∼19-24 Mya. Most Euwallacea spp. appear to be associated with one species of Fusarium, but two species farmed two closely related fusaria. Euwallacea sp. #2 in Miami-Dade County, Florida cultivated Fusarium spp. AF-6 and AF-8 on avocado, and Euwallacea sp. #4 farmed Fusarium ambrosium AF-1 and Fusarium sp. AF-11 on Chinese tea in Sri Lanka. Cophylogenetic analyses indicated that the Euwallacea and Fusarium phylogenies were largely incongruent, apparently due to the beetles switching fusarial symbionts (i.e., host shifts) at least five times during the evolution of this mutualism. Three cospeciation events between Euwallacea and their AFC symbionts were detected, but randomization tests failed to reject the null hypothesis that the putative parallel cladogenesis is a stochastic pattern. Lastly, two collections of Euwallacea sp. #2 from Miami

  16. Root Hairs

    PubMed Central

    Grierson, Claire; Nielsen, Erik; Ketelaarc, Tijs; Schiefelbein, John

    2014-01-01

    Roots hairs are cylindrical extensions of root epidermal cells that are important for acquisition of nutrients, microbe interactions, and plant anchorage. The molecular mechanisms involved in the specification, differentiation, and physiology of root hairs in Arabidopsis are reviewed here. Root hair specification in Arabidopsis is determined by position-dependent signaling and molecular feedback loops causing differential accumulation of a WD-bHLH-Myb transcriptional complex. The initiation of root hairs is dependent on the RHD6 bHLH gene family and auxin to define the site of outgrowth. Root hair elongation relies on polarized cell expansion at the growing tip, which involves multiple integrated processes including cell secretion, endomembrane trafficking, cytoskeletal organization, and cell wall modifications. The study of root hair biology in Arabidopsis has provided a model cell type for insights into many aspects of plant development and cell biology. PMID:24982600

  17. A new allergen from ragweed (Ambrosia artemisiifolia) with homology to art v 1 from mugwort.

    PubMed

    Léonard, Renaud; Wopfner, Nicole; Pabst, Martin; Stadlmann, Johannes; Petersen, Bent O; Duus, Jens Ø; Himly, Martin; Radauer, Christian; Gadermaier, Gabriele; Razzazi-Fazeli, Ebrahim; Ferreira, Fatima; Altmann, Friedrich

    2010-08-27

    Art v 1, the major pollen allergen of the composite plant mugwort (Artemisia vulgaris) has been identified recently as a thionin-like protein with a bulky arabinogalactan-protein moiety. A close relative of mugwort, ragweed (Ambrosia artemisiifolia) is an important allergen source in North America, and, since 1990, ragweed has become a growing health concern in Europe as well. Weed pollen-sensitized patients demonstrated IgE reactivity to a ragweed pollen protein of apparently 29-31 kDa. This reaction could be inhibited by the mugwort allergen Art v 1. The purified ragweed pollen protein consisted of a 57-amino acid-long defensin-like domain with high homology to Art v 1 and a C-terminal proline-rich domain. This part contained hydroxyproline-linked arabinogalactan chains with one galactose and 5 to 20 and more alpha-arabinofuranosyl residues with some beta-arabinoses in terminal positions as revealed by high field NMR. The ragweed protein contained only small amounts of the single hydroxyproline-linked beta-arabinosyl residues, which form an important IgE binding determinant in Art v 1. cDNA clones for this protein were obtained from ragweed flowers. Immunological characterization revealed that the recombinant ragweed protein reacted with >30% of the weed pollen allergic patients. Therefore, this protein from ragweed pollen constitutes a novel important ragweed allergen and has been designated Amb a 4. PMID:20576600

  18. Modeling the dispersion of Ambrosia artemisiifolia L. pollen with the model system COSMO-ART.

    PubMed

    Zink, Katrin; Vogel, Heike; Vogel, Bernhard; Magyar, Donát; Kottmeier, Christoph

    2012-07-01

    Common ragweed (Ambrosia artemisiifolia L.) is a highly allergenic plant that is spreading throughout Europe. Ragweed pollen can be transported over large distances by the wind. Even low pollen concentrations of less than 10 pollen m(-3) can lead to health problems in sensitive persons. Therefore, forecasting the airborne concentrations of ragweed pollen is becoming more and more important for public health. The question remains whether distant pollen sources need to be considered in reliable forecasts. We used the extended numerical weather prediction system COSMO-ART to simulate the release and transport of ragweed pollen in central Europe. A pollen episode (September 12-16, 2006) in north-eastern Germany was modeled in order to find out where the pollen originated. For this purpose, several different source regions were taken into account and their individual impact on the daily mean pollen concentration and the performance of the forecast were studied with the means of a 2 × 2 contingency table and skill scores. It was found that the majority of the pollen originated in local areas, but up to 20% of the total pollen load came from distant sources in Hungary. It is concluded that long-distance transport should not be neglected when predicting pollen concentrations. PMID:21744099

  19. Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen.

    PubMed

    Pasqualini, Stefania; Tedeschini, Emma; Frenguelli, Giuseppe; Wopfner, Nicole; Ferreira, Fatima; D'Amato, Gennaro; Ederli, Luisa

    2011-10-01

    Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O(3)) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O(3) fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O(3) fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O(3), determined from the mRNA levels of the major allergens. We conclude that O(3) can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase. PMID:21605929

  20. Paving the way for invasive species: road type and the spread of common ragweed (Ambrosia artemisiifolia).

    PubMed

    Joly, Martin; Bertrand, Pascale; Gbangou, Roland Y; White, Marie-Catherine; Dubé, Jean; Lavoie, Claude

    2011-09-01

    Roads function as prime habitats and corridors for invasive plant species. Yet despite the diversity of road types, there is little research on the influence of these types on the spread of invaders. Common ragweed (Ambrosia artemisiifolia), a plant producing large amounts of allergenic pollen, was selected as a species model for examining the impact of road type on the spread of invasive plants. We examined this relationship in an agricultural region of Quebec, Canada. We mapped plant distribution along different road types, and constructed a model of species presence. Common ragweed was found in almost all sampling sites located along regional (97%) and local paved (81%) roads. However, verges of unpaved local roads were rarely (13%) colonized by the plant. A model (53% of variance explained), constructed with only four variables (paved regional roads, paved local roads, recently mown road verges, forest cover), correctly predicted (success rate: 89%) the spatial distribution of common ragweed. Results support the hypothesis that attributes associated with paved roads strongly favour the spread of an opportunistic invasive plant species. Specifically, larger verges and greater disturbance associated with higher traffic volume create propitious conditions for common ragweed. To date, emphasis has been placed on controlling the plant in agricultural fields, even though roadsides are probably a much larger seed source. Strategies for controlling the weed along roads have only focused on major highways, even though the considerable populations along local roads also contribute to the production of pollen. Management prioritizations developed to control common ragweed are thus questionable. PMID:21710219

  1. Examination of common ragweed's (Ambrosia artemisiifolia L.) allelopathic effect on some weed species.

    PubMed

    Lehoczky, E; Szabó, R; Nelima, M Okumu; Nagy, P; Béres, I

    2010-01-01

    In the last decades the importance of some weed species increased in Hungary. The common ragweed (Ambrosia artemisiifolia L.) also belongs to this group. The allelopathic effect of watery extract made from different plant parts of common ragweed (air dried leafy shoots, seeds) were studied on the germination and growth of some weed species. The extracts were prepared with tap water, chopped dry plant materials were added to water and 24 hours later the material was filtered. The germination took place in a Binder KBW type thermostat in dark. 25 seeds were put into one Petri-dish, adding 15 ml plant extract to each in four repeats. The timing of germination was checked in every two days and the rate of growth was estimated after a week, by counting the numbers of germinated seeds and measuring the length of the radicle and plumula. The measured data were statistically analysed and the effect of extracts on germinating ratio and seedling length were evaluated. PMID:21542474

  2. Paving the Way for Invasive Species: Road Type and the Spread of Common Ragweed ( Ambrosia artemisiifolia)

    NASA Astrophysics Data System (ADS)

    Joly, Martin; Bertrand, Pascale; Gbangou, Roland Y.; White, Marie-Catherine; Dubé, Jean; Lavoie, Claude

    2011-09-01

    Roads function as prime habitats and corridors for invasive plant species. Yet despite the diversity of road types, there is little research on the influence of these types on the spread of invaders. Common ragweed ( Ambrosia artemisiifolia), a plant producing large amounts of allergenic pollen, was selected as a species model for examining the impact of road type on the spread of invasive plants. We examined this relationship in an agricultural region of Quebec, Canada. We mapped plant distribution along different road types, and constructed a model of species presence. Common ragweed was found in almost all sampling sites located along regional (97%) and local paved (81%) roads. However, verges of unpaved local roads were rarely (13%) colonized by the plant. A model (53% of variance explained), constructed with only four variables (paved regional roads, paved local roads, recently mown road verges, forest cover), correctly predicted (success rate: 89%) the spatial distribution of common ragweed. Results support the hypothesis that attributes associated with paved roads strongly favour the spread of an opportunistic invasive plant species. Specifically, larger verges and greater disturbance associated with higher traffic volume create propitious conditions for common ragweed. To date, emphasis has been placed on controlling the plant in agricultural fields, even though roadsides are probably a much larger seed source. Strategies for controlling the weed along roads have only focused on major highways, even though the considerable populations along local roads also contribute to the production of pollen. Management prioritizations developed to control common ragweed are thus questionable.

  3. Adaptive divergence for a fitness-related trait among invasive Ambrosia artemisiifolia populations in France.

    PubMed

    Chun, Young Jin; LE Corre, Valérie; Bretagnolle, François

    2011-04-01

    The impact of natural selection on the adaptive divergence of invasive populations can be assessed by testing the null hypothesis that the extent of quantitative genetic differentiation (Q(ST) ) would be similar to that of neutral molecular differentiation (F(ST) ). Using eight microsatellite loci and a common garden approach, we compared Q(ST) and F(ST) among ten populations of an invasive species Ambrosia artemisiifolia (common ragweed) in France. In a common garden study with varying water and nutrient levels, we measured Q(ST) for five traits (height, total biomass, reproductive allocation, above- to belowground biomass ratio, and days to flowering). Although low F(ST) indicated weak genetic structure and strong gene flow among populations, we found significant diversifying selection (Q(ST) > F(ST) ) for reproductive allocation that may be closely related to fitness. It suggests that abiotic conditions may have exerted selection pressure on A. artemisiifolia populations to differentiate adaptively, such that populations at higher altitude or latitude evolved greater reproductive allocation. As previous studies indicate multiple introductions from various source populations of A. artemisiifolia in North America, our results suggest that the admixture of introduced populations may have increased genetic diversity and additive genetic variance, and in turn, promoted the rapid evolution and adaptation of this invasive species. PMID:21306459

  4. Yeast Associated with the Ambrosia Beetle, Platypus koryoensis, the Pest of Oak Trees in Korea

    PubMed Central

    Yun, Yeo Hong; Suh, Dong Yeon; Yoo, Hun Dal; Oh, Man Hwan

    2015-01-01

    Oak tree death caused by symbiosis of an ambrosia beetle, Platypus koryoensis, and an ophiostomatoid filamentous fungus, Raffaelea quercus-mongolicae, has been a nationwide problem in Korea since 2004. In this study, we surveyed the yeast species associated with P. koryoensis to better understand the diversity of fungal associates of the beetle pest. In 2009, a total of 195 yeast isolates were sampled from larvae and adult beetles (female and male) of P. koryoensis in Cheonan, Goyang, and Paju; 8 species were identified by based on their morphological, biochemical and molecular analyses. Meyerozyma guilliermondii and Candida kashinagacola were found to be the two dominant species. Among the 8 species, Candida homilentoma was a newly recorded yeast species in Korea, and thus, its mycological characteristics were described. The P. koryoensis symbiont R. quercusmongolicae did not show extracelluar CM-cellulase, xylanase and avicelase activity that are responsible for degradation of wood structure; however, C. kashinagacola and M. guilliermondii did show the three extracellular enzymatic activities. Extracelluar CM-cellulase activity was also found in Ambrosiozyma sp., C. homilentoma, C. kashinagacola, and Candida sp. Extracelluar pectinase activity was detected in Ambrosiozyma sp., C. homilentoma, Candida sp., and M. guilliermondii. All the 8 yeast species displayed compatible relationships with R. quercus-mongolicae when they were co-cultivated on yeast extract-malt extract plates. Overall, our results demonstrated that P. koryoensis carries the yeast species as a symbiotic fungal associate. This is first report of yeast diversity associated with P. koryoensis. PMID:26839506

  5. Effects of seed traits variation on seedling performance of the invasive weed, Ambrosia artemisiifolia L.

    NASA Astrophysics Data System (ADS)

    Ortmans, William; Mahy, Grégory; Monty, Arnaud

    2016-02-01

    Seedling performance can determine the survival of a juvenile plant and impact adult plant performance. Understanding the factors that may impact seedling performance is thus critical, especially for annuals, opportunists or invasive plant species. Seedling performance can vary among mothers or populations in response to environmental conditions or under the influence of seed traits. However, very few studies have investigated seed traits variations and their consequences on seedling performance. Specifically, the following questions have been addressed by this work: 1) How the seed traits of the invasive Ambrosia artemisiifolia L. vary among mothers and populations, as well as along the latitude; 2) How do seed traits influence seedling performance; 3) Is the influence on seedlings temperature dependent. With seeds from nine Western Europe ruderal populations, seed traits that can influence seedling development were measured. The seeds were sown into growth chambers with warmer or colder temperature treatments. During seedling growth, performance-related traits were measured. A high variability in seed traits was highlighted. Variation was determined by the mother identity and population, but not latitude. Together, the temperature, population and the identity of the mother had an effect on seedling performance. Seed traits had a relative impact on seedling performance, but this did not appear to be temperature dependent. Seedling performance exhibited a strong plastic response to the temperature, was shaped by the identity of the mother and the population, and was influenced by a number of seed traits.

  6. The long distance transport (LDT) of Ambrosia pollen from the Pannonian Plain to Scandinavia

    NASA Astrophysics Data System (ADS)

    Šikoparija, B..; Skjøth, C. A.; Alm Kübler, K.; Dahl, A.; Radišić, P.; Sommer, J.; Grewling, Ł.; Smith, M.

    2012-04-01

    Ragweed (Ambrosia spp.) pollen grains are important aeroallergens that cause seasonal allergic rhinitis and asthma to sensitive individuals. This study describes the conditions required for the LDT of ragweed pollen from the Pannonian Plain (PP) to Sweden on the 27- 28 August 2011, using a combination of daily and bi-hourly pollen count data, the overall synoptic weather situation, 3D analysis of the regional scale orography using Digital Elevation Models, surface meteorological data, satellite observations, and air mas trajectories calculated using the HYSPLIT model. During the episode, high pressure (1024-1028 hPa) situated over European Russia and the Black Sea to the east and deep low pressure (~990 hPa) over the British Isles in the northwest resulted in a general southeast-northwest movement of air, and the occurrence of the jet-effect Kosava wind in the PP. This dry and gusty wind caused ragweed pollen release on the PP and pollen to be transported to the northwest. A foehn wind that governs air movement down leeward slopes into the PP was also active. The 24 and 25 August 2011 were very hot and caused large amounts of ragweed pollen to be released and taken high up in the atmosphere through convection. Such conditions also resulted in high Planetary Boundary Layers over the entire area, conditions that facilitated the transport of pollen over areas of low elevation on the Western Carpathians (i.e. the Moravian Gate or Low Baskid passes) northward into Poland and beyond.

  7. Modeling the dispersion of Ambrosia artemisiifolia L. pollen with the model system COSMO-ART

    NASA Astrophysics Data System (ADS)

    Zink, Katrin; Vogel, Heike; Vogel, Bernhard; Magyar, Donát; Kottmeier, Christoph

    2012-07-01

    Common ragweed ( Ambrosia artemisiifolia L.) is a highly allergenic plant that is spreading throughout Europe. Ragweed pollen can be transported over large distances by the wind. Even low pollen concentrations of less than 10 pollen m-3 can lead to health problems in sensitive persons. Therefore, forecasting the airborne concentrations of ragweed pollen is becoming more and more important for public health. The question remains whether distant pollen sources need to be considered in reliable forecasts. We used the extended numerical weather prediction system COSMO-ART to simulate the release and transport of ragweed pollen in central Europe. A pollen episode (September 12-16, 2006) in north-eastern Germany was modeled in order to find out where the pollen originated. For this purpose, several different source regions were taken into account and their individual impact on the daily mean pollen concentration and the performance of the forecast were studied with the means of a 2 × 2 contingency table and skill scores. It was found that the majority of the pollen originated in local areas, but up to 20% of the total pollen load came from distant sources in Hungary. It is concluded that long-distance transport should not be neglected when predicting pollen concentrations.

  8. Life history trait differentiation and local adaptation in invasive populations of Ambrosia artemisiifolia in China.

    PubMed

    Li, Xiao-Meng; She, Deng-Ying; Zhang, Da-Yong; Liao, Wan-Jin

    2015-03-01

    Local adaptation has been suggested to play an important role in range expansion, particularly among invasive species. However, the extent to which local adaptation affects the success of an invasive species and the factors that contribute to local adaptation are still unclear. This study aimed to investigate a case of population divergence that may have contributed to the local adaptation of invasive populations of Ambrosia artemisiifolia in China. Common garden experiments in seven populations indicated clinal variations along latitudinal gradients, with plants from higher latitudes exhibiting earlier flowering and smaller sizes at flowering. In reciprocal transplant experiments, plants of a northern Beijing origin produced more seeds at their home site than plants of a southern Wuhan origin, and the Wuhan-origin plants had grown taller at flowering than the Beijing-origin plants in Wuhan, which is believed to facilitate pollen dispersal. These results suggest that plants of Beijing origin may be locally adapted through female fitness and plants from Wuhan possibly locally adapted through male fitness. Selection and path analysis suggested that the phenological and growth traits of both populations have been influenced by natural selection and that flowering time has played an important role through its direct and indirect effects on the relative fitness of each individual. This study evidences the life history trait differentiation and local adaptation during range expansion of invasive A. artemisiifolia in China. PMID:25362583

  9. Yeast Associated with the Ambrosia Beetle, Platypus koryoensis, the Pest of Oak Trees in Korea.

    PubMed

    Yun, Yeo Hong; Suh, Dong Yeon; Yoo, Hun Dal; Oh, Man Hwan; Kim, Seong Hwan

    2015-12-01

    Oak tree death caused by symbiosis of an ambrosia beetle, Platypus koryoensis, and an ophiostomatoid filamentous fungus, Raffaelea quercus-mongolicae, has been a nationwide problem in Korea since 2004. In this study, we surveyed the yeast species associated with P. koryoensis to better understand the diversity of fungal associates of the beetle pest. In 2009, a total of 195 yeast isolates were sampled from larvae and adult beetles (female and male) of P. koryoensis in Cheonan, Goyang, and Paju; 8 species were identified by based on their morphological, biochemical and molecular analyses. Meyerozyma guilliermondii and Candida kashinagacola were found to be the two dominant species. Among the 8 species, Candida homilentoma was a newly recorded yeast species in Korea, and thus, its mycological characteristics were described. The P. koryoensis symbiont R. quercusmongolicae did not show extracelluar CM-cellulase, xylanase and avicelase activity that are responsible for degradation of wood structure; however, C. kashinagacola and M. guilliermondii did show the three extracellular enzymatic activities. Extracelluar CM-cellulase activity was also found in Ambrosiozyma sp., C. homilentoma, C. kashinagacola, and Candida sp. Extracelluar pectinase activity was detected in Ambrosiozyma sp., C. homilentoma, Candida sp., and M. guilliermondii. All the 8 yeast species displayed compatible relationships with R. quercus-mongolicae when they were co-cultivated on yeast extract-malt extract plates. Overall, our results demonstrated that P. koryoensis carries the yeast species as a symbiotic fungal associate. This is first report of yeast diversity associated with P. koryoensis. PMID:26839506

  10. 1991 New Mexico economic impact study for the Uranium Mill Tailings Remedial Action Project, Ambrosia Lake, New Mexico, site

    SciTech Connect

    Not Available

    1991-06-01

    The University of New Mexico Bureau of Business and Economic Research completed an abbreviated cost-benefit analysis of the income and employment impact of the US Department of Energy (DOE) and contractor offices in Albuquerque. Since the Project Office will have a significant positive impact on the State`s economy (shown on Table 8), the impact is combined with the impact of remedial actions at the Ambrosia Lake site to highlight the cost-benefit of the entire Uranium Mill Tailings Remedial Action (UMTRA) Project. The UMTRA Project at the Ambrosia Lake site will generate $12.509 million in gross labor income in New Mexico between 1989 and 1994. This includes $1.161 million in federal tax revenue, $1.015 million in State personal income tax revenue, and seven thousand in local tax revenue. The UMTRA Project will generate the equivalent of 84 full-time jobs during the peak year of remedial action at Ambrosia Lake site. New Mexico`s total funding requirement for the UMTRA Project is estimated to be $2.963 million. The net economic benefit of the Ambrosia Lake portion of the UMTRA Project to New Mexico after the State`s share of the project`s cost, the federal income tax, and the $0.936 million income impact of the alternate use of the State funding are subtracted, will be $7.451 million between 1990 and 1994. In Fiscal Year 1990 the UMTRA Project DOE and contractor offices in Albuquerque directly employed 163 people. Another 78 jobs were also maintained in support of the industry sector and 166 jobs were also maintained in other sections of the New Mexico economy. It is estimated that $19 million dollars of income was generated and 1.949 million of State and local taxes were collected. The University of New Mexico study shows that for every dollar the State of New Mexico invests in the UMTRA Project, it will realize $95.05 in gross labor income. This corresponds to a net return on the States investment in the Project of $97.20 for every dollar invested.

  11. Natural Terpenoids from Ambrosia Species Are Active In Vitro and In Vivo against Human Pathogenic Trypanosomatids

    PubMed Central

    Frank, Fernanda M.; Laurella, Laura C.; Muschietti, Liliana V.; Catalán, Cesar A.; Martino, Virginia S.; Malchiodi, Emilio L.

    2013-01-01

    Among the natural compounds, terpenoids play an important role in the drug discovery process for tropical diseases. The aim of the present work was to isolate antiprotozoal compounds from Ambrosia elatior and A. scabra. The sesquiterpene lactone (STL) cumanin was isolated from A. elatior whereas two other STLs, psilostachyin and cordilin, and one sterol glycoside, daucosterol, were isolated from A. scabra. Cumanin and cordilin were active against Trypanosoma cruzi epimastigotes showing 50% inhibition concentrations (IC50) values of 12 µM and 26 µM, respectively. Moreover, these compounds are active against bloodstrean trypomastigotes, regardless of the T. cruzi strain tested. Psilostachyin and cumanin were also active against amastigote forms with IC50 values of 21 µM and 8 µM, respectively. By contrast, daucosterol showed moderate activity on epimastigotes and trypomastigotes and was inactive against amastigote forms. We also found that cumanin and psilostachyin exhibited an additive effect in their trypanocidal activity when these two drugs were tested together. Cumanin has leishmanicidal activity with growth inhibition values greater than 80% at a concentration of 5 µg/ml (19 µM), against both L. braziliensis and L. amazonensis promastigotes. In an in vivo model of T. cruzi infection, cumanin was more active than benznidazole, producing an 8-fold reduction in parasitemia levels during the acute phase of the infection compared with the control group, and more importantly, a reduction in mortality with 66% of the animals surviving, in comparison with 100% mortality in the control group. Cumanin also showed nontoxic effects at the doses assayed in vivo, as determined using markers of hepatic damage. PMID:24130916

  12. Attraction of the redbay ambrosia beetle, Xyleborus glabratus, to avocado, lychee, and essential oil Lures.

    PubMed

    Kendra, Paul E; Montgomery, Wayne S; Niogret, Jerome; Peña, Jorge E; Capinera, John L; Brar, Gurpreet; Epsky, Nancy D; Heath, Robert R

    2011-09-01

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is an exotic wood-boring insect that vectors the mycopathogen responsible for laurel wilt, a lethal vascular disease of trees in the Lauraceae. High mortality has occurred in native Persea species in the southeastern U.S., and the vector-pathogen complex poses an imminent threat to the production of commercial avocado, P. americana, in south Florida. There is a critical need for effective attractants to detect, monitor, and control this invasive pest. This study combined field tests and laboratory bioassays to evaluate the response of female X. glabratus to host-based volatiles from wood of avocado (cultivars of West Indian, Guatemalan, and Mexican races); from wood of lychee (Litchi chinensis, a presumed non-host that is high in the sesquiterpene α-copaene, a putative attractant); and to commercial lures containing manuka and phoebe oils, two reported attractive baits. Volatile collections and GC-MS analyses were performed to quantify the sesquiterpene content of test substrates. In the field, traps baited with lychee wood captured more beetles than those with wood from avocado cultivars; traps baited with phoebe oil lures captured more beetles than those with manuka oil lures (the current monitoring tool). In field and laboratory tests, X. glabratus did not show a preference among avocado races in either attraction or host acceptance (initiation of boring). In choice tests, lychee was more attractive than avocado initially, but a higher percentage of beetles bored into avocado, suggesting that lychee emits more powerful olfactory/visual cues, but that avocado contains more of the secondary cues necessary for host recognition. Emissions of α-copaene, β-caryophyllene, and α-humulene were correlated with field captures, and lychee wood may be a source of additional semiochemicals for X. glabratus. PMID:21789550

  13. Engineering assessment of inactive uranium mill tailings: Phillips/United Nuclear site, Ambrosia Lake, New Mexico

    SciTech Connect

    1981-10-01

    Ford, Bacon and Davis Utah, Inc., has reevaluated the Phillips/United Nuclear site in order to revise the December 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Ambrosia Lake, New Mexico. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from 2.6 million dry tons of tailings at the Phillips/United Nuclear site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material, to removal of the tailings to remote disposal sites and decontamination of the tailings site. Cost estimates for the four options range from about $21,500,000 for stabilization in-place, to about $45,200,000 for disposal at a distance of about 15 mi. Three principal alternatives for the reprocessing of the Phillips/United Nuclear tailings were examined: heap leaching; treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing.The cost of the uranium recovered would be about $87/lb of U/sub 3/O/sub 8/ by either heap leach or conventional plant process. The spot market price for uranium was $25/lb early in 1981. Reprocessing the Phillips/United Nuclear tailings for uranium recovery does not appear to be economically attractive under present or foreseeable market conditions.

  14. Allergic Rhinitis and Asthma in Southern Croatia: Impact of Sensitization to Ambrosia elatior

    PubMed Central

    Cvitanović, Slavica; Znaor, Ljubo; Kanceljak-Macan, Božica; Macan, Jelena; Gudelj, Ivan; Grbić, Dragica

    2007-01-01

    Aim To identify pollen types in southern Croatia and investigate the impact of sensitization to Ambrosia elatior (A. elatior) on symptoms and treatment of patients with seasonal allergic rhinitis and/or asthma. Methods The study recruited 120 patients from Split-Dalmatian County with seasonal rhinitis and asthma symptoms and positive skin prick test to one or more common inhaled allergens. Patients with positive skin prick test and increased specific IgE to A. elatior (n = 56) were included in the follow-up study during the A. elatior pollen season. Rhinitis and asthma symptoms were scored and drug treatment recorded using standardized questionnaires. Also, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), and eosinophil count in peripheral blood were measured. Type and pollen concentration of A. elatior in the air over the nine-week pollen season were determined on the glass slides using the gravimetric method. The results were expressed as the proportion of A. elatior pollen in the total pollen. Results Fifty-six of 120 patients (46.7%) were sensitized to A. elatior. Its proportion in total pollen peaked to 12% in the first week of September. Forty-one patients who completed the follow-up study showed a significantly higher score of symptoms during this peak period than in the beginning of the pollen season for seasonal allergic rhinitis (median±interquartile range, 50 ± 11 vs 7 ± 4; P<0.001) and for seasonal allergic asthma (median±interquartile range, 12 ± 2 vs 0 ± 0; P<0.001). Conclusion A. elatior is an important cause of seasonal allergic rhinitis and asthma and must be included in the routine diagnostic procedures in southern Croatia. PMID:17309141

  15. Variability and Cryptic Heteromorphism of Ambrosia artemisiifolia Seeds: What Consequences for its Invasion in France?

    PubMed Central

    Fumanal, Boris; Chauvel, Bruno; Sabatier, Anne; Bretagnolle, François

    2007-01-01

    Background and Aims: Ambrosia artemisiifolia is a ruderal weed introduced from North America to Europe. It produces large amount of achenes which are highly heterogeneous in size. Due to the preponderant role of propagules in invasive plant processes, the achene mass variability related to germination, dispersal strategy and life history traits of offspring were investigated within this species. Methods: The variability in achene mass was quantified among six populations sampled in different habitats. The effects of achene mass variation on germination were studied. The percentages of floating and non-floating achenes were evaluated in the studied populations. The consequences of floatability on the growth and traits of the offspring were studied. Key Results: Mean achene mass ranged from 1·72 to 3·60 mg, depending on the populations, and was highly variable. Variation among achenes within plants accounted for 63·9 % of the variance, whereas variances among plants within each population (22·2 %) and among populations (13·9 %) were lower. Achene masses were also positively correlated to the total germination percentage for four populations out of six. Two kinds of achenes were distinguished: floating and non-floating. The majority of floating achenes (90 %) sank 24 h after water immersion. Whatever the population, floating achenes were lighter, more dormant and germinated faster than non-floating achenes. Plants which issued from floating achenes had better growth than those from non-floating achenes. Conclusions: The capacity of A. artemisiifolia to be invasive in Europe appears to be high, possibly due to its huge plasticity in seed mass which may help it to cope with a wide range of conditions and to establish in disturbed habitats. Furthermore, the recent invasion of southern France by A. artemisiifolia could be partially explained by water dispersal of achenes through rivers and has pinpointed its colonization potential along French rivers. PMID:17575284

  16. Chemical control of ambrosia Artemisiifolia on non-crop areas: are there alternatives to glyphosate?

    PubMed

    Lombard, A; Gauvrit, C; Chauvel, B

    2005-01-01

    We compared glyphosate, glufosinate and metsulfuron-methyl to control Ambrosia artemisiifolia under non-crop conditions. A laboratory study showed that A. artemisiifolia is an easy-to-wet species and that glufosinate and glyphosate are quickly absorbed by its leaves (nearly 100% in 24 h). Metsulfuron-methyl absorption was slower (about 50% in 24 h) but was strongly promoted by terpenic alcohol and esterified rapeseed oil. In the greenhouse, all three herbicides were efficacious against A. artemisiifolia, with ED50s of <23, 23 and 0.8 g ha(-1) for glufosinate, glyphosate and metsulfuron-methyl, respectively. These results were confirmed on a non-crop area for glufosinate and glyphosate, which at half the registered dose reached high efficacies at both the 4 to 6-node and flowering stages of A. artemisiifolia. By contrast, metsulfuron-methyl showed no efficacy. However, after treatment at the 4- to 6-node stage, new emergence of A. artemisiifolia led to the presence of vigorous plants that bore numerous flowers and produced high levels of pollen. After treatment at the flowering stage, flower production by A. artemisiifolia was not significantly affected, but achene weight was decreased by 60 to 70% and seed viability was only 8 to 13% for the treated plants, as compared to 85% for the control. No significant difference was observed between the two herbicides and between the doses. It is concluded that glufosinate can be an alternative to glyphosate for the chemical control of A. artemisiifolia on non-crop areas. However, with both herbicides, it is difficult to attain the two objectives of reducing seed production and pollen production by means of only one treatment. PMID:16637214

  17. Roots and Root Function: Introduction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A number of current issues related to water management, ecohydrology, and climate change are giving impetus to new research aimed at understanding roots and their functioning. Current areas of research include: use of advanced imaging technologies such as Magnetic Resonance Imaging to observe roots...

  18. An Asian ambrosia beetle Euwallacea fornicatus and its novel symbiotic fungus Fusarium sp. pose a serious threat to the Israeli avocado industry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ambrosia beetle Euwallacea fornicatus Einchoff was first recorded in Israel in 2009. A novel unnamed symbiotic species within Clade 3 of the Fusarium solani species complex, carried in the mandibular mycangia of the beetle, is responsible for the typical wilt symptoms inflicted on avocado (Perse...

  19. Abundance in Persea americana of the Redbay Ambrosia Beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), Vector of Laurel Wilt: A Case of Intra-guild Competition?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle, Xyleborus glabratus is a pest of plant species in the Lauraceae, including Persea borbonia, P. pallustris, P. americana, and others. Xyleborus glabratus infestation levels in P. borbonia maintain a high proportion compared to other species, such as Xylosandrus crassiuscu...

  20. Ability of Stress-Related Volatiles to Attract and Induce Attacks by Xylosandrus Germanus (Coleoptera: Curculionidae, Scolytinae) and Other Ambrosia Beetles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1 Xylosandrus germanus typically colonizes physiologically-stressed deciduous hosts, but it is increasingly being recognized as a key pest of ornamental nursery stock. We tested the attractiveness of common plant stress-related volatiles to ambrosia beetles occupying the nursery agroecosystem, and t...

  1. Remedial action plan and site conceptual design for stabilization of the inactive uranium mill tailings site at Ambrosia Lake, New Mexico

    SciTech Connect

    Not Available

    1991-11-01

    This volume deals with the main construction subcontract for the uranium mill tailings remedial action of Ambrosia Lake, New Mexico. Contents of subcontract documents AMB-4 include: bidding requirements; terms and conditions; specifications which cover general requirements and sitework; and subcontract drawings.

  2. Evaluation of commercial formulations of entomopathogenic fungi to manage the redbay ambrosia beetle, vector of Laurel wilt, a lethal disease affecting avocados in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle (RAB), Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae) vectors the fungal pathogen, Raffaelea lauricola, which causes laurel wilt (LW), a lethal disease of trees in the family Lauraceae, including the most commercially important crop in this family, avocado, Pe...

  3. Entomopathogenic fungi as a biological control agents for the vector of the laurel wilt disease, the redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle (RAB), Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae) vectors the fungal pathogen, Raffaelea lauricola, which causes laurel wilt (LW), a lethal disease of trees in the family Lauraceae, including the most commercially important crop in this family, avocado, Pe...

  4. Association of the symbiotic fungi Fusarium euwallaceae, Graphium sp. and Acremonium sp., with the ambrosia beetle Euwallacea nr. fornicatus in avocado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ambrosia beetle, Euwallacea nr. fornicatus (Coleoptera:Scolytinae), is a new invasive species to Israel. To date, the beetle has been recorded from 48 tree species representing 25 plant families. Amongst the most affected are avocado, castor-bean and box elder. Isolations from beetle heads revea...

  5. Interruption of the semiochemical-based attraction of ambrosia beetles to ethanol-baited traps and ethanol-injected trap trees by Verbenone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined the ability of verbenone, a bark beetle anti-aggregation pheromone, to interrupt the semiochemical-based attraction of ambrosia beetles. Field trapping studies conducted in Ohio showed that a verbenone dispenser with a release rate of 50 mg / d at 25 oC reduced the attraction of Anisandr...

  6. USDA-ARS strategies to address the imminent threat of redbay ambrosia beetle and laurel wilt disease to avocados in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laurel wilt, a deadly fungal disease of avocado and other trees in the Lauraceae, is vectored by the redbay ambrosia beetle (Xyleborus glabratus). First detected in GA in 2002, the beetle has spread to SC and FL to within 70 miles of commercial avocado areas. Impact is potentially devastating to the...

  7. Volatile chemicals from host and non-host trees of the redbay ambrosia beetle Xyleborus glabratus, threatening the Floridian avocado production.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle Xyleborus glabratus (Coleoptera: Scolytinae) is an invasive pest introduced in spreading in Southeastern US. The beetle carries a symbiotic fungus which causes laurel wilt, a vascular disease killing of host trees of the Laureacea family as 6 weeks. We compare the chemical...

  8. Supplement to the site observational work plan for the UMTRA Project Site at Ambrosia Lake, New Mexico

    SciTech Connect

    1996-02-01

    The purpose of this document is to provide additional and more detailed information to supplement review of the site observational work plan (SOWP) for the Ambrosia Lake, New Mexico, Uranium Mill Tailings Remedial Action (UMTRA) Project site. This document includes a discussion of (1) the average linear velocity of the ground water in the alluvium; (2) the ground water quality of the alluvium, weathered Mancos Shale, and the Tres Hermanos-C Member of the Mancos Shale; and (3) the fate and transport of contaminants from the uppermost aquifer to the Westwater Canyon Member of the Morrison Formation. The data from a 1989 aquifer test were analyzed using the curve-matching software AQTESOLV and then compared with the original results. A hydrograph of the ground water elevations in monitoring wells screened in the alluvium is presented to show how the ground water elevations change with time. Stiff and Piper diagrams were created to describe the changes in ground water geochemistry in the alluvium/weathered Mancos Shale unit, the Tres Hermanos-C Sandstone unit, the Tres Hermanos-B Sandstone unit, and the Dakota Sandstone. Background information on other related topics such as site history, cell construction, soil characteristics, and well construction are presented in the SOWP. Figure 1 is a geologic cross section depicting the conceptual model of the hydrostratigraphy and ground water chemistry of the Ambrosia Lake site. Table 1 presents hydrogeologic information of each hydrostratigraphic unit.

  9. Supplement to the site observational work plan for the UMTRA project site at Ambrosia Lake, New Mexico

    SciTech Connect

    1995-11-01

    The purpose of this document is to provide additional and more detailed information to supplement review of the site observational work plan (SOWP) (DOE, 1995) for the Ambrosia Lake, New Mexico, Uranium Mill Tailings Remedial Action (UMTRA) Project site. This document includes a discussion of the average linear velocity of the ground water in the alluvium and a discussion of the ground water quality of the alluvium, weathered Mancos Shale, and the Tres Hermanos-C Member of the Mancos Shale. The data from a 1989 aquifer test were analyzed using the curve-matching software AQTESOLV and then compared with the original results. A hydrograph of the ground water elevations in monitoring wells screened in the alluvium is presented to show how the ground water elevations change with time. Stiff and Piper diagrams were created to describe the changes in ground water geochemistry in the alluvium/weathered Mancos Sahel unit, the Tres Hermanos-C Sandstone unit, the Tres Hermanos-B Sandstone unit, and the Dakota Sandstone. Background information on other related topics such as site history, cell construction, soil characteristics, and well construction are presented in the SOWP. A geologic cross section depicts the conceptual model of the hydrostratigraphy and ground water chemistry of the Ambrosia Lake site. Hydrogeologic information of each hydrostratigraphic unit is presented.

  10. Flood Stress as a Technique to Assess Preventive Insecticide and Fungicide Treatments for Protecting Trees against Ambrosia Beetles.

    PubMed

    Ranger, Christopher M; Schultz, Peter B; Reding, Michael E; Frank, Steven D; Palmquist, Debra E

    2016-01-01

    Ambrosia beetles tunnel into the heartwood of trees where they cultivate and feed upon a symbiotic fungus. We assessed the effectiveness of flood stress for making Cercis canadensis L. and Cornus florida L. trees attractive to attack as part of insecticide and fungicide efficacy trials conducted in Ohio and Virginia. Since female ambrosia beetles will not begin ovipositing until their symbiotic fungus is established within the host, we also assessed pre-treatment of trees with permethrin, azoxystrobin, and potassium phosphite on fungal establishment and beetle colonization success. Permethrin reduced attacks on flooded trees, yet no attacks occurred on any of the non-flooded trees. Fewer galleries created within flooded trees pre-treated with permethrin, azoxystrobin, and potassium phosphite contained the purported symbiotic fungus; foundress' eggs were only detected in flooded but untreated trees. While pre-treatment with permethrin, azoxystrobin, and potassium phosphite can disrupt colonization success, maintaining tree health continues to be the most effective and sustainable management strategy. PMID:27548230

  11. Automated Root Tracking with "Root System Analyzer"

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  12. Root gravitropism

    NASA Technical Reports Server (NTRS)

    Masson, P. H.

    1995-01-01

    When a plant root is reoriented within the gravity field, it responds by initiating a curvature which eventually results in vertical growth. Gravity sensing occurs primarily in the root tip. It may involve amyloplast sedimentation in the columella cells of the root cap, or the detection of forces exerted by the mass of the protoplast on opposite sides of its cell wall. Gravisensing activates a signal transduction cascade which results in the asymmetric redistribution of auxin and apoplastic Ca2+ across the root tip, with accumulation at the bottom side. The resulting lateral asymmetry in Ca2+ and auxin concentration is probably transmitted to the elongation zone where differential cellular elongation occurs until the tip resumes vertical growth. The Cholodny-Went theory proposes that gravity-induced auxin redistribution across a gravistimulated plant organ is responsible for the gravitropic response. However, recent data indicate that the gravity-induced reorientation is more complex, involving both auxin gradient-dependent and auxin gradient-independent events.

  13. Root canal

    MedlinePlus

    Endodontic therapy ... the root of a tooth. Generally, there is pain and swelling in the area. The infection can ... You may have some pain or soreness after the procedure. An over-the-counter anti-inflammatory drug, such as ibuprofen or naproxen, can help relieve ...

  14. Gene flow and population admixture as the primary post-invasion processes in common ragweed (Ambrosia artemisiifolia) populations in France.

    PubMed

    Chun, Young Jin; Fumanal, Boris; Laitung, Beryl; Bretagnolle, François

    2010-03-01

    *An improved inference of the evolutionary history of invasive species may be achieved by analyzing the genetic variation and population differentiation of recently established populations and their ancestral (historical) populations. Employing this approach, we investigated the role of gene flow in the post-invasion evolution of common ragweed (Ambrosia artemisiifolia). *Using eight microsatellite loci, we compared genetic diversity and structure among nine pairs of historical and recent populations in France. Historical populations were reconstructed from herbarium specimens dated from the late 19th to early 20th century, whereas recent populations were collected within the last 5 yr. *Recent populations showed greater allelic and genetic diversity than did historical populations. Recent populations exhibited a lower level of population differentiation, shorter genetic distances among populations and more weakly structured populations than did historical populations. *Our results suggest that currently invasive populations have arisen from active gene flow and the subsequent admixture of historical populations, incorporating new alleles from multiple introductions. PMID:20028474

  15. UV and visible light screening by individual sporopollenin exines derived from Lycopodium clavatum (club moss) and Ambrosia trifida (giant ragweed).

    PubMed

    Atkin, Stephen L; Barrier, Sylvain; Cui, Zhenggang; Fletcher, Paul D I; Mackenzie, Grahame; Panel, Vincent; Sol, Vincent; Zhang, Xunli

    2011-03-01

    We have investigated the UV-visible light transmission of three types of micrometre-sized sporopollenin exine shells, two derived from Lycopodium clavatum (club moss) spores and one from Ambrosia trifida (giant ragweed) pollen. We have used spectrophotometer measurements of partial monolayers of exines and microscope absorbance imaging to derive the light transmission properties of individual exines. Measurements have been made for exines in air when light transmission losses are due to a combination of absorption, reflection and scattering processes and for exines dispersed in a liquid for which the refractive index (RI) is approximately equal to the RI of the exine such that reflection and scattering effects are negligible. Overall, it found that the light transmission of a single exine wall is approximately 50%. This value of the transmission is due mainly to light absorption, is similar for the three exines studied here and varies only slightly with light wavelength over the range 200-900 nm. PMID:21232973

  16. Comparison of three types of traps baited with sexual pheromones for ambrosia beetle Megaplatypus mutatus (Coleoptera: Platypodinae) in poplar plantations.

    PubMed

    Funes, Hernán; Zerba, Eduardo; González Audino, Paola

    2009-08-01

    Megaplatypus mutatus (Coleoptera: Platypodinae) is an ambrosia beetle native to South America that only attacks standing live trees and is a serious problem for commercial poplar (Populus L.; Salicaceae) plantations in Argentina. The development of traps baited with synthetic pheromones that can be used for monitoring M. mutatus in infested poplar plantations is an important goal in preventive programs. Pioneer male M. mutatus emit a pheromone composed mainly by (+)-sulcatol and sulcatone. In the current study, we tested their release rates from several polymeric reservoir systems, to develop and manufacture a pheromone-releasing device. The efficacy of three different types of traps was evaluated in the field. Single funnel traps equipped with cross-vanes (CIPEIN-CV) captured significantly more insects than multiple funnel traps (LINDGREN) and simple funnel traps (CIPEIN-F). PMID:19736767

  17. [Spread of Ambrosia elatior in rural areas (investigation performed during the years 1985 and 1986 in southern Drome)].

    PubMed

    Couturier, P

    1987-06-01

    The settings of Ambrosia development are not only construction zones, waste grounds, road works; a country extension has been observed; more and more varied lands under cultivation (cereals, sunflowers, peach-trees...) are overgrown and the advance, toward South Drome and Ardèche since few years, clearly indicates that all the Rhone Valley is under threat. Several forms of spreading are possible, sometimes very unexpected, so, for instance, the irrigation by spraying. The struggle must associate the mowing when it is easy (town zones, verges...), selective weed-killer use and a good farming rotation (country zones). A better information of town councils about those problems is also absolutely necessary for us. PMID:3454180

  18. A survey of the weevils of Ukraine. Bark and ambrosia beetles (Coleoptera: Curculionidae: Platypodinae and Scolytinae).

    PubMed

    Nikulina, Tatyana; Mandelshtam, Mikhail; Petrov, Alexander; Nazarenko, Vitalij; Yunakov, Nikolai

    2015-01-01

    Our knowledge of Ukrainian bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae and Platypodinae) is summarized as a baseline for future studies of the fauna, with a checklist including information on distribution, host trees, biology and taxonomy. One hundred twenty-two species are recorded from Ukraine, of which seven are recorded for the first time. One species is recorded for the first time from Europe. Previous records of 24 species are considered dubious and requiring confirmation. In contrast to the Palaearctic Catalogue (Knížek 2011b), we consider Anisandrus maiche to be first described by Kurentsov (1941) rather than by Eggers (1942); A. maiche (Eggers, 1942) is a junior synonym of A. maiche (Kurentsov, 1941).  PMID:25661778

  19. Ragweed (Ambrosia artemisiifolia) pollen allergenicity: SuperSAGE transcriptomic analysis upon elevated CO2 and drought stress

    PubMed Central

    2014-01-01

    Background Pollen of common ragweed (Ambrosia artemisiifolia) is a main cause of allergic diseases in Northern America. The weed has recently become spreading as a neophyte in Europe, while climate change may also affect the growth of the plant and additionally may also influence pollen allergenicity. To gain better insight in the molecular mechanisms in the development of ragweed pollen and its allergenic proteins under global change scenarios, we generated SuperSAGE libraries to identify differentially expressed transcripts. Results Ragweed plants were grown in a greenhouse under 380 ppm CO2 and under elevated level of CO2 (700 ppm). In addition, drought experiments under both CO2 concentrations were performed. The pollen viability was not altered under elevated CO2, whereas drought stress decreased its viability. Increased levels of individual flavonoid metabolites were found under elevated CO2 and/or drought. Total RNA was isolated from ragweed pollen, exposed to the four mentioned scenarios and four SuperSAGE libraries were constructed. The library dataset included 236,942 unique sequences, showing overlapping as well as clear differently expressed sequence tags (ESTs). The analysis targeted ESTs known in Ambrosia, as well as in pollen of other plants. Among the identified ESTs, those encoding allergenic ragweed proteins (Amb a) increased under elevated CO2 and drought stress. In addition, ESTs encoding allergenic proteins in other plants were also identified. Conclusions The analysis of changes in the transcriptome of ragweed pollen upon CO2 and drought stress using SuperSAGE indicates that under global change scenarios the pollen transcriptome was altered, and impacts the allergenic potential of ragweed pollen. PMID:24972689

  20. Attraction of Redbay Ambrosia Beetle, Xyleborus Glabratus, To Leaf Volatiles of its Host Plants in North America.

    PubMed

    Martini, Xavier; Hughes, Marc A; Smith, Jason A; Stelinski, Lukasz L

    2015-07-01

    The redbay ambrosia beetle, Xyleborus glabratus, is an important pest of redbay (Persea borbonia) and swamp bay (P. palustris) trees in forests of the southeastern USA. It is also a threat to commercially grown avocado. The beetle is attracted to host wood volatiles, particularly sesquiterpenes. Contrary to other ambrosia beetles that attack stressed, possibly pathogen-infected, and dying trees, X. glabratus readily attacks healthy trees. To date little is known about the role of leaf volatiles in the host selection behavior and ecology of X. glabratus. To address this question, an olfactometer bioassay was developed to test the behavioral response of X. glabratus to plant leaf volatiles. We found that X. glabratus was attracted to the leaf odors of their hosts, redbay and swamp bay, with no attraction to a non-host tree tested (live oak, Quercus virginiana), which served as a negative control. Gas chromatography-mass spectrometry (GS/MS) analysis of leaves revealed the absence of sesquiterpenes known to be attractive to X. glabratus and present in host wood, suggesting that additional leaf-derived semiochemicals may serve as attractants for this beetle. An artificial blend of chemicals was developed based on GC/MS analyses of leaf volatiles and behavioral assays. This blend was attractive to X. glabratus at a level that rivaled currently used lures for practical monitoring of this pest. This synthetic redbay leaf blend also was tested in the field. Baited traps captured more X. glabratus than unbaited controls and equivalently to manuka oil lures. We hypothesize that leaf volatiles may be used by X. glabratus as an additional cue for host location. PMID:26070721

  1. Trace elements in the pollen of Ambrosia artemisiifolia: what is the effect of soil concentrations?

    PubMed

    Cloutier-Hurteau, Benoît; Gauthier, Stefanie; Turmel, Marie-Claude; Comtois, Paul; Courchesne, François

    2014-01-01

    Concentrations of nine trace elements (Ba, Cd, Cr, Cu, Mn, Ni, Pb, Tl and Zn) were measured in a plant bearing allergenic pollens (ragweed) and their transfers from soils to the roots and then to the pollens were investigated. The soil, roots and pollens collected from flowers were sampled at 26 urban sites. Soil pH, soil organic carbon and total-recoverable trace elements (TE) in soil, roots and pollens were measured. The three biogeochemical compartments are well discriminated according to their TE concentrations. The concentrations (in μg g(-1)) in pollens decreased as follow: Zn (59.5-205)>Mn (19.4-117)>Ba≈Cr≈Cu≈Ni≈Pb (0.54-27.7)>Cd (0.06-0.77)>Tl (0.0015-0.0180). Mean elemental allocation within ragweed always favored roots over pollen but, at site level, inverse pattern is also observed mostly for Zn and slightly for Cu and Ni. Significant predictive models of TE concentrations in pollens were obtained using soil or root properties only for Cd, Ni and Pb. They all involved positive relationships between TE concentrations in pollens and in soil or roots. Estimates of short-term exposure of human to TE carried out by ragweed pollens indicate TE absorption of less than 50 ng, far below thresholds of air quality criteria. Investigating the TE chemistry of pollens is a required first step to validate the impact of TE in pollens on human health and on the prevalence and intensity of allergy symptoms and atopic diseases. PMID:24183625

  2. The Ambrosia Lake project archaeological investigations of three small sites associated with the southern Chacoan outlier of Kin Nizhoni, McKinley County, New Mexico

    SciTech Connect

    Cullington, B.J.; Hammack, L.C.; Baugh, T.G.

    1990-03-15

    During the fall of 1987, Complete Archaeological Service Associates conducted mitigative excavations at three sites (LA50363, LA50364, and LA50371) in McKinley County, New Mexico. These sites are adjacent to the Phillips/United Nuclear Inactive Uranium Mill and Tailings site at Ambrosia Lake, New Mexico. The primary deposition at each of these sites appears to be related to a Pueblo II or Bonito Phase occupation. Temporal placement is based primarily on the cross dating of ceramics and archaeomagnetic determinations when possible. No tree-ring or radiocarbon samples are available from these sites. These Ambrosia Lake sites indicate that this area was occupied primarily by Pueblo II people who may have had close social, economic, and ceremonial ties with the people living at the nuclear community of Lower Nizhoni about 3 km south-southeast. The later component at LA50364 indicates a Pueblo III occupation by people who may have had similar ties to the people of the Kin Nizhoni nuclear community. The Ambrosia Lake sites, then, provide important information on the structure of subnuclear communities within the southern Chaco periphery.

  3. Effects of elevated CO2 on fine root dynamics in a Mojave Desert community: A FACE study

    USGS Publications Warehouse

    Phillips, D.L.; Johnson, M.G.; Tingey, D.T.; Catricala, C.E.; Hoyman, T.L.; Nowak, R.S.

    2006-01-01

    Fine roots (??? 1mm diameter) are critical in plant water and nutrient absorption, and it is important to understand how rising atmospheric CO2 will affect them as part of terrestrial ecosystem responses to global change. This study's objective was to determine effects of elevated CO2 on production, mortality, and standing crops of fine root length over 2 years in a free-air CO2 enrichment (FACE) facility in the Mojave Desert of southern Nevada, USA. Three replicate 25m diameter FACE rings were maintained at ambient (??? 370 ??mol mol-1) and elevated CO2 (??? 550 ??mol mol-1) atmospheric concentrations. Twenty-eight minirhizotron tubes were placed in each ring to sample three microsite locations: evergreen Larrea shrubs, drought-deciduous Ambrosia shrubs, and along systematic community transects (primarily in shrub interspaces which account for ??? 85% of the area). Seasonal dynamics were similar for ambient and elevated CO2: fine root production peaked in April-June, with peak standing crop occurring about 1 month later, and peak mortality occurring during the hot summer months, with higher values for all three measures in a wet year compared with a dry year. Fine root standing crop, production, and mortality were not significantly different between treatments except standing crop along community transects, where fine root length was significantly lower in elevated CO2. Fine root turnover (annual cumulative mortality/mean standing crop) ranged from 2.33 to 3.17 year-1, and was not significantly different among CO2 treatments, except for community transect tubes where it was significantly lower for elevated CO2. There were no differences in fine root responses to CO2 between evergreen (Larrea) and drought-deciduous (Ambrosia) shrubs. Combined with observations of increased leaf-level water-use efficiency and lack of soil moisture differences, these results suggest that under elevated CO2 conditions, reduced root systems (compared with ambient CO2) appear sufficient

  4. Pythium Root Rot (and Feeder Root Necrosis)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pythium species cause a number of diseases on corn. Among the Pythium diseases, root rot presents the least conspicuous aboveground symptoms. Broadly defined, root rot also includes feeder root necrosis. At least 16 species of Pythium are known to cause root rot of corn. These include P. acanthicu...

  5. Prevalence of sensitization to weed pollens of Humulus scandens, Artemisia vulgaris, and Ambrosia artemisiifolia in northern China

    PubMed Central

    Hao, Guo-dong; Zheng, Yi-wu; Gjesing, Birgitte; Kong, Xing-ai; Wang, Jing-yuan; Song, Zhi-jing; Lai, Xu-xin; Zhong, Nan-shan; Spangfort, Michael D.

    2013-01-01

    Objective: Weed pollens are common sources of allergens worldwide. The prevalence of weed pollen sensitization is not yet fully known in China. The purpose of this study was to investigate the prevalence of sensitization to weed allergens from Artemisia, Ambrosia, and Humulus in northern China. Methods: A total of 1 144 subjects (aged from 5 to 68 years) visiting our clinic from June to October 2011 underwent intradermal testing using a panel of 25 allergen sources. Subjects with positive skin responses to any pollen were further tested for their serum concentrations of IgE antibodies against Artemisia vulgaris, Ambrosia artemisiifolia, and Humulus scandens, and against the purified allergens, Art v 1 and Amb a 1. Results: Of 1 144 subjects, 170 had positive intradermal reactions to pollen and 144 donated serum for IgE testing. The prevalence of positive intradermal responses to pollens of Artemisia sieversiana, Artemisia annua, A. artemisiifolia, and H. scandens was 11.0%, 10.2%, 3.7%, and 6.6%, respectively. Among the intradermal positive subjects, the prevalence of specific IgE antigens to A. vulgaris was 58.3%, to A. artemisiifolia 14.7%, and to H. scandens 41.0%. The prevalence of specific IgE antigens to the allergen Art v 1 was 46.9%, and to Amb a 1 was 11.2%. The correlation between the presence of IgE antibodies specific to A. vulgaris and to the Art v 1 antigen was very high. Subjects with A. artemisiifolia specific IgE also had A. vulgaris specific IgE, but with relatively high levels of A. vulgaris IgE antibodies. There were no correlations between the presence of IgE antibodies to H. scandens and A. vulgaris or to H. scandens and A. artemisiifolia. Conclusions: The intradermal prevalence of weed pollen sensitization among allergic subjects in northern China is about 13.5%. Correlations of specific IgE antibodies suggest that pollen allergens from Artemisia and Humulus are independent sources for primary sensitization. PMID:23463767

  6. Characterization of a Plasmopara species on Ambrosia artemisiifolia, and notes on P. halstedii, based on morphology and multiple gene phylogenies.

    PubMed

    Choi, Young-Joon; Kiss, Levente; Vajna, László; Shin, Hyeon-Dong

    2009-10-01

    Common ragweed (Ambrosia artemisiifolia) is an invasive and highly allergenic plant species, on which two species, Plasmopara halstedii and Plasmopara angustiterminalis, have been recognized to cause downy mildew disease. In this study, morphological and molecular patterns of seven Plasmopara specimens collected from A. artemisiifolia in Canada, Hungary, and USA were compared with those of P. halstedii and P. angustiterminalis from Helianthus and Xanthium, respectively. Analyses of partial sequences of three genes, namely those for the large subunit (28S) of rDNA, cytochrome c oxidase subunit II (COX2), and NADH dehydrogenase subunit I (ND1) of mtDNA, were carried out to examine the phylogenetic relationships among these specimens using both Bayesian and maximum parsimony methods. All the phylogenetic analyses revealed that the downy mildew pathogens infecting A. artemisiifolia in Hungary and North America clearly represent a lineage distinct from other Plasmopara taxa investigated. The shape of sporangia and the width of trunks and branches also allowed the separation of the specimens parasitic to A. artemisiifolia from P. halstedii on Helianthus annuus and P. angustiterminalis on Xanthium strumarium. Surprisingly, the Hungarian and the Canadian specimens were more closely related to each other than to those from the USA based on COX2 and ND1 mtDNA data, although the D1/D2/D3 sequences of 28S rDNA were identical in all these Plasmopara specimens. The regional distribution of the mtDNA haplotypes seen in this study suggests a transatlantic migration has occurred and would be interesting to follow up with a more detailed sampling. To investigate the diversity within P. halstedii sensu lato, infecting different host plant species, specimens from six asteraceous genera, Ambrosia, Flaveria, Helianthus, Siegesbeckia, Solidago, and Xanthium, were also included in molecular analyses. These represented six distinct lineages according to the host plant genera. These

  7. History of the Exotic Ambrosia Beetles Euwallacea interjectus and Euwallacea validus (Coleoptera: Curculionidae: Xyleborini) in the United States.

    PubMed

    Cognato, Anthony I; Hoebeke, E Richard; Kajimura, Hisashi; Smith, Sarah M

    2015-06-01

    Exotic insects are constantly intercepted at U.S. ports-of-entry. Of these, wood-boring beetles, particularly xyleborine ambrosia beetles, are sometimes missed during port inspections and become established in the United States. Euwallacea validus (Eichhoff) and Euwallacea interjectus (Blandford) are morphologically similar Asian ambrosia beetle species that vary by their fungal associates and their potential to cause economic damage. Euwallacea validus and E. interjectus were first discovered in New York (1975) and Hawaii (1976), respectively. Euwallacea validus was collected multiple times from widely separated localities and is assumed to have spread throughout the eastern United States. The discovery of E. interjectus in Florida (2011) and Texas (2011) prompted our review of the E. validus specimens because of the potential misidentification of the species. In addition, using mitochondrial cytochrome oxidase I (COI) DNA data and phylogenetic analysis, we tested the hypothesis that multiple introductions account for the U.S. populations of E. interjectus and E. validus. Our review of 7,184 specimens revealed an earlier introduction to the mainland for E. interjectus, which was first collected from Louisiana in 1984. This species is distributed in the South while E. validus occurs in the North with a known area of syntopy in northeastern Georgia. The extent of the syntopy within the United States is unknown and further investigation is required. Phylogenetic analysis of 24 E. interjectus and 20 E. validus individuals resolved clades that associated with each species and gross geographic provenance. Four well-supported clades represented E. interjectus which included the following localities: 1) Hawaii and Thailand; 2) Vietnam, Taiwan, and Texas; 3) Okinawa (Japan); and 4) Japan and several southern U.S. states. One clade comprised all E. validus specimens from Japan and the mainland United States. Four and two haplotypes were found for the E. interjectus and E

  8. Growth and foliar d15N of a Mojave desert shrub in relation to soil hydrological dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foliar 15N ratios (del15N), % N, and canopy volumes were measured in the two Mojave Desert dominant shrubs, the evergreen Larrea tridentata and drought deciduous Ambrosia dumosa growing across a geomorphically determined soil mosaic. Across three soils with increasingly strong age-dependent surface...

  9. Colonization of Artificially Stressed Black Walnut Trees by Ambrosia Beetle, Bark Beetle, and Other Weevil Species (Coleoptera: Curculionidae) in Indiana and Missouri.

    PubMed

    Reed, Sharon E; Juzwik, Jennifer; English, James T; Ginzel, Matthew D

    2015-12-01

    Thousand cankers disease (TCD) is a new disease of black walnut (Juglans nigra L.) in the eastern United States. The disease is caused by the interaction of the aggressive bark beetle Pityophthorus juglandis Blackman and the canker-forming fungus, Geosmithia morbida M. Kolarik, E. Freeland, C. Utley & Tisserat, carried by the beetle. Other insects also colonize TCD-symptomatic trees and may also carry pathogens. A trap tree survey was conducted in Indiana and Missouri to characterize the assemblage of ambrosia beetles, bark beetles, and other weevils attracted to the main stems and crowns of stressed black walnut. More than 100 trees were girdled and treated with glyphosate (Riverdale Razor Pro, Burr Ridge, Illinois) at 27 locations. Nearly 17,000 insects were collected from logs harvested from girdled walnut trees. These insects represented 15 ambrosia beetle, four bark beetle, and seven other weevil species. The most abundant species included Xyleborinus saxeseni Ratzburg, Xylosandrus crassiusculus Motschulsky, Xylosandrus germanus Blandford, Xyleborus affinis Eichhoff, and Stenomimus pallidus Boheman. These species differed in their association with the stems or crowns of stressed trees. Multiple species of insects were collected from individual trees and likely colonized tissues near each other. At least three of the abundant species found (S. pallidus, X. crassiusculus, and X. germanus) are known to carry propagules of canker-causing fungi of black walnut. In summary, a large number of ambrosia beetles, bark beetles, and other weevils are attracted to stressed walnut trees in Indiana and Missouri. Several of these species have the potential to introduce walnut canker pathogens during colonization. PMID:26314028

  10. Remedial action plan and site conceptual design for stabilization of the inactive uranium mill tailings site at Ambrosia Lake, New Mexico

    SciTech Connect

    Matthews, M.L. . Uranium Mill Tailings Remedial Action Project Office); Mitzelfelt, R. . Environmental Improvement Div.)

    1991-11-01

    This Remedial Action Plan (RAP) has been developed to serve a dual purpose. It presents the series of activities that is proposed by the US Department of Energy (DOE) to stabilize and control radioactive materials at the inactive Phillips/United Nuclear uranium processing site designated as the Ambrosia Lake site in McKinley County, New Mexico. It also serves to document the concurrence of both State of New Mexico and the US Nuclear Regulatory Commission (NRC) in the remedial action. This agreement, upon execution by the DOE and the state and concurrence by NRC, becomes Appendix B of the Cooperative Agreement.

  11. No evolutionary shift in the mating system of north American Ambrosia artemisiifolia (Asteraceae) following its introduction to China.

    PubMed

    Li, Xiao-Meng; Liao, Wan-Jin; Wolfe, Lorne M; Zhang, Da-Yong

    2012-01-01

    The mating system plays a key role during the process of plant invasion. Contemporary evolution of uniparental reproduction (selfing or asexuality) can relieve the challenges of mate limitation in colonizing populations by providing reproductive assurance. Here we examined aspects of the genetics of colonization in Ambrosia artemisiifolia, a North American native that is invasive in China. This species has been found to possess a strong self-incompatibility system and have high outcrossing rates in North America and we examined whether there has been an evolutionary shift towards the dependence on selfing in the introduced range. Specifically, we estimated outcrossing rates in one native and five invasive populations and compared levels of genetic diversity between North America and China. Based on six microsatellite loci we found that, like the native North American population, all five Chinese populations possessed a completely outcrossing mating system. The estimates of paternity correlations were low, ranging from 0.028-0.122, which suggests that populations possessed ~8-36 pollen donor parents contributing to each maternal plant in the invasive populations. High levels of genetic diversity for both native and invasive populations were found with the unbiased estimate of gene diversity ranging from 0.262-0.289 for both geographic ranges based on AFLP markers. Our results demonstrate that there has been no evolutionary shift from outcrossing to selfing during A. artemisiifolia's invasion of China. Furthermore, high levels of genetic variation in North America and China indicate that there has been no erosion of genetic variance due to a bottleneck during the introduction process. We suggest that the successful invasion of A. artemisiifolia into Asia was facilitated by repeated introductions from multiple source populations in the native range creating a diverse gene pool within Chinese populations. PMID:22384104

  12. Summary of the engineering assessment of inactive uranium mill tailings: Phillips/United Nuclear site, Ambrosia Lake, New Mexico

    SciTech Connect

    1981-10-01

    Ford, Bacon and Davis Utah, Inc., has reevaluated the Phillips/United Nuclear site in order to revise the December 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Ambrosia Lake, New Mexico. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 2.6 million dry tons of tailings at the Phillips/United Nuclear site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material, to removal of the tailings to remote disposal sites and decontamination of the tailings site. Cost estimates for the four options range from about $21,500,000 for stabilization in-place, to about $45,200,000 for disposal at a distance of about 15 mi. Three principal alternatives for the reprocessing of the Phillips/United Nuclear tailings were examined: heap leaching; treatment at an existing mill; reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $87/lb of U/sub 3/O/sub 8/ by either heap leach or conventional plant process. The spot market price for uranium was $25/lb early in 1981. Reprocessing the Phillips/United Nuclear tailings for uranium recovery does not appear to be economically attractive under present or foreseeable market conditions.

  13. Cubeb Oil Lures: Terpenoid Emissions, Trapping Efficacy, and Longevity for Attraction of Redbay Ambrosia Beetle (Coleoptera: Curculionidae: Scolytinae).

    PubMed

    Kendra, Paul E; Niogret, Jerome; Montgomery, Wayne S; Deyrup, Mark A; Epsky, Nancy D

    2015-02-01

    Redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is an exotic wood borer and the primary vector of Raffaelea lauricola, a symbiotic fungus that causes laurel wilt. This lethal disease has decimated native redbay [Persea borbonia (L.) Sprengel] and swampbay [Persea palustris (Rafinesque) Sargent] throughout southeastern U.S. forests, and currently threatens avocado (Persea americana Miller) in Florida. To curtail the spread of laurel wilt, effective attractants are needed for early detection of the vector. Phoebe oil lures were the best known attractant for X. glabratus, but they are no longer available. The current detection system uses manuka oil lures, but previous research indicated that manuka lures have a short field life in Florida. Recently, cubeb oil was identified as a new attractant for X. glabratus, and cubeb bubble lures are now available commercially. This study compared trapping efficacy and field longevity of cubeb and manuka lures with phoebe lures that had been in storage since 2010 over a 12-wk period in south Florida. In addition, terpenoid emissions were quantified from cubeb and manuka lures aged outdoors for 12 wk. Captures were comparable with all three lures for 3 wk, but by 4 wk, captures with manuka were significantly less. Equivalent captures were obtained with cubeb and phoebe lures for 7 wk, but captures with cubeb were significantly greater from 8 to 12 wk. Our results indicate that cubeb bubble lures are the most effective tool currently available for detection of X. glabratus, with a field life of 3 months due to extended low release of attractive sesquiterpenes, primarily α-copaene and α-cubebene. PMID:26470139

  14. A new approach used to explore associations of current Ambrosia pollen levels with current and past meteorological elements.

    PubMed

    Matyasovszky, István; Makra, László; Csépe, Zoltán; Deák, Áron József; Pál-Molnár, Elemér; Fülöp, Andrea; Tusnády, Gábor

    2015-09-01

    The paper examines the sensitivity of daily airborne Ambrosia (ragweed) pollen levels of a current pollen season not only on daily values of meteorological variables during this season but also on the past meteorological conditions. The results obtained from a 19-year data set including daily ragweed pollen counts and ten daily meteorological variables are evaluated with special focus on the interactions between the phyto-physiological processes and the meteorological elements. Instead of a Pearson correlation measuring the strength of the linear relationship between two random variables, a generalised correlation that measures every kind of relationship between random vectors was used. These latter correlations between arrays of daily values of the ten meteorological elements and the array of daily ragweed pollen concentrations during the current pollen season were calculated. For the current pollen season, the six most important variables are two temperature variables (mean and minimum temperatures), two humidity variables (dew point depression and rainfall) and two variables characterising the mixing of the air (wind speed and the height of the planetary boundary layer). The six most important meteorological variables before the current pollen season contain four temperature variables (mean, maximum, minimum temperatures and soil temperature) and two variables that characterise large-scale weather patterns (sea level pressure and the height of the planetary boundary layer). Key periods of the past meteorological variables before the current pollen season have been identified. The importance of this kind of analysis is that a knowledge of the past meteorological conditions may contribute to a better prediction of the upcoming pollen season. PMID:25376632

  15. A new approach used to explore associations of current Ambrosia pollen levels with current and past meteorological elements

    NASA Astrophysics Data System (ADS)

    Matyasovszky, István; Makra, László; Csépe, Zoltán; Deák, Áron József; Pál-Molnár, Elemér; Fülöp, Andrea; Tusnády, Gábor

    2015-09-01

    The paper examines the sensitivity of daily airborne Ambrosia (ragweed) pollen levels of a current pollen season not only on daily values of meteorological variables during this season but also on the past meteorological conditions. The results obtained from a 19-year data set including daily ragweed pollen counts and ten daily meteorological variables are evaluated with special focus on the interactions between the phyto-physiological processes and the meteorological elements. Instead of a Pearson correlation measuring the strength of the linear relationship between two random variables, a generalised correlation that measures every kind of relationship between random vectors was used. These latter correlations between arrays of daily values of the ten meteorological elements and the array of daily ragweed pollen concentrations during the current pollen season were calculated. For the current pollen season, the six most important variables are two temperature variables (mean and minimum temperatures), two humidity variables (dew point depression and rainfall) and two variables characterising the mixing of the air (wind speed and the height of the planetary boundary layer). The six most important meteorological variables before the current pollen season contain four temperature variables (mean, maximum, minimum temperatures and soil temperature) and two variables that characterise large-scale weather patterns (sea level pressure and the height of the planetary boundary layer). Key periods of the past meteorological variables before the current pollen season have been identified. The importance of this kind of analysis is that a knowledge of the past meteorological conditions may contribute to a better prediction of the upcoming pollen season.

  16. North American Lauraceae: terpenoid emissions, relative attraction and boring preferences of redbay ambrosia beetle, Xyleborus glabratus (coleoptera: curculionidae: scolytinae).

    PubMed

    Kendra, Paul E; Montgomery, Wayne S; Niogret, Jerome; Pruett, Grechen E; Mayfield, Albert E; MacKenzie, Martin; Deyrup, Mark A; Bauchan, Gary R; Ploetz, Randy C; Epsky, Nancy D

    2014-01-01

    The invasive redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of Raffaelea lauricola, a symbiotic fungus and the etiologic agent of laurel wilt. This lethal disease has caused severe mortality of redbay (Persea borbonia) and swampbay (P. palustris) trees in the southeastern USA, threatens avocado (P. americana) production in Florida, and has potential to impact additional New World species. To date, all North American hosts of X. glabratus and suscepts of laurel wilt are members of the family Lauraceae. This comparative study combined field tests and laboratory bioassays to evaluate attraction and boring preferences of female X. glabratus using freshly-cut bolts from nine species of Lauraceae: avocado (one cultivar of each botanical race), redbay, swampbay, silkbay (Persea humilis), California bay laurel (Umbellularia californica), sassafras (Sassafras albidum), northern spicebush (Lindera benzoin), camphor tree (Cinnamomum camphora), and lancewood (Nectandra coriacea). In addition, volatile collections and gas chromatography-mass spectroscopy (GC-MS) were conducted to quantify terpenoid emissions from test bolts, and electroantennography (EAG) was performed to measure olfactory responses of X. glabratus to terpenoids identified by GC-MS. Significant differences were observed among treatments in both field and laboratory tests. Silkbay and camphor tree attracted the highest numbers of the beetle in the field, and lancewood and spicebush the lowest, whereas boring activity was greatest on silkbay, bay laurel, swampbay, and redbay, and lowest on lancewood, spicebush, and camphor tree. The Guatemalan cultivar of avocado was more attractive than those of the other races, but boring response among the three was equivalent. The results suggest that camphor tree may contain a chemical deterrent to boring, and that different cues are associated with host location and host acceptance. Emissions of α-cubebene, α-copaene, α-humulene, and calamenene were

  17. North American Lauraceae: Terpenoid Emissions, Relative Attraction and Boring Preferences of Redbay Ambrosia Beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

    PubMed Central

    Kendra, Paul E.; Montgomery, Wayne S.; Niogret, Jerome; Pruett, Grechen E.; Mayfield, Albert E.; MacKenzie, Martin; Deyrup, Mark A.; Bauchan, Gary R.; Ploetz, Randy C.; Epsky, Nancy D.

    2014-01-01

    The invasive redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of Raffaelea lauricola, a symbiotic fungus and the etiologic agent of laurel wilt. This lethal disease has caused severe mortality of redbay (Persea borbonia) and swampbay (P. palustris) trees in the southeastern USA, threatens avocado (P. americana) production in Florida, and has potential to impact additional New World species. To date, all North American hosts of X. glabratus and suscepts of laurel wilt are members of the family Lauraceae. This comparative study combined field tests and laboratory bioassays to evaluate attraction and boring preferences of female X. glabratus using freshly-cut bolts from nine species of Lauraceae: avocado (one cultivar of each botanical race), redbay, swampbay, silkbay (Persea humilis), California bay laurel (Umbellularia californica), sassafras (Sassafras albidum), northern spicebush (Lindera benzoin), camphor tree (Cinnamomum camphora), and lancewood (Nectandra coriacea). In addition, volatile collections and gas chromatography-mass spectroscopy (GC-MS) were conducted to quantify terpenoid emissions from test bolts, and electroantennography (EAG) was performed to measure olfactory responses of X. glabratus to terpenoids identified by GC-MS. Significant differences were observed among treatments in both field and laboratory tests. Silkbay and camphor tree attracted the highest numbers of the beetle in the field, and lancewood and spicebush the lowest, whereas boring activity was greatest on silkbay, bay laurel, swampbay, and redbay, and lowest on lancewood, spicebush, and camphor tree. The Guatemalan cultivar of avocado was more attractive than those of the other races, but boring response among the three was equivalent. The results suggest that camphor tree may contain a chemical deterrent to boring, and that different cues are associated with host location and host acceptance. Emissions of α-cubebene, α-copaene, α-humulene, and calamenene were

  18. Fusarium euwallaceae sp. nov.--a symbiotic fungus of Euwallacea sp., an invasive ambrosia beetle in Israel and California.

    PubMed

    Freeman, S; Sharon, M; Maymon, M; Mendel, Z; Protasov, A; Aoki, T; Eskalen, A; O'Donnell, K

    2013-01-01

    The invasive Asian ambrosia beetle Euwallacea sp. (Coleoptera, Scolytinae, Xyleborini) and a novel Fusarium sp. that it farms in its galleries as a source of nutrition causes serious damage to more than 20 species of live trees and pose a serious threat to avocado production (Persea americana) in Israel and California. Adult female beetles are equipped with mandibular mycangia in which its fungal symbiont is transported within and from the natal galleries. Damage caused to the xylem is associated with disease symptoms that include sugar or gum exudates, dieback, wilt and ultimately host tree mortality. In 2012 the beetle was recorded on more than 200 and 20 different urban landscape species in southern California and Israel respectively. Euwallacea sp. and its symbiont are closely related to the tea shot-hole borer (E. fornicatus) and its obligate symbiont, F. ambrosium occurring in Sri Lanka and India. To distinguish these beetles, hereafter the unnamed xyleborine in Israel and California will be referred to as Euwallacea sp. IS/CA. Both fusaria exhibit distinctive ecologies and produce clavate macroconidia, which we think might represent an adaption to the species-specific beetle partner. Both fusaria comprise a genealogically exclusive lineage within Clade 3 of the Fusarium solani species complex (FSSC) that can be differentiated with arbitrarily primed PCR. Currently these fusaria can be distinguished only phenotypically by the abundant production of blue to brownish macroconidia in the symbiont of Euwallacea sp. IS/CA and their rarity or absence in F. ambrosium. We speculate that obligate symbiosis of Euwallacea and Fusarium, might have driven ecological speciation in these mutualists. Thus, the purpose of this paper is to describe and illustrate the novel, economically destructive avocado pathogen as Fusarium euwallaceae sp. nov. S. Freeman et al. PMID:23928415

  19. The redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) uses stem silhouette diameter as a visual host-finding cue.

    PubMed

    Mayfield, Albert E; Brownie, Cavell

    2013-08-01

    The redbay ambrosia beetle (Xyleborus glabratus Eichhoff) is an invasive pest and vector of the pathogen that causes laurel wilt disease in Lauraceous tree species in the eastern United States. This insect uses olfactory cues during host finding, but use of visual cues by X. glabratus has not been previously investigated and may help explain diameter-related patterns in host tree mortality. The objective of this study was to determine whether X. glabratus females visually detect silhouettes of tree stems during host finding and are more likely to land on large diameter stems than smaller ones. Three field experiments were conducted in which stem silhouettes (black cylinders or standing nonhost pines) of varying diameters and identical capture surface areas were baited with essential oil lures. The Log10-transformed number of X. glabratus trapped per week increased as a function of silhouette diameter in 2011 and 2012, using artificial silhouette diameters ranging 2-18 and 3-41 cm, respectively. When lures and capture surfaces were attached to standing pines ranging 4-37 cm in diameter, a positive relationship between Log10(X. glabratus trap catch) and stem diameter was modeled using nonlinear quadratic plateau regression and indicated a diameter above which visual attraction was not enhanced; however, there was not a maximum diameter for enhanced X. glabratus attraction that was generally consistent across all experiments. These results 1) indicate that X. glabratus incorporates visual information during host finding, 2) help explain diameter-related patterns of redbay (Persea borbonia (L.) Sprengel) mortality observed during laurel wilt epidemics, and 3) are applicable to the management of this forest pest. PMID:23905737

  20. Remedial action plan and site conceptual design for stabilization of the inactive uranium mill tailings site at Ambrosia Lake, New Mexico. Volume 3, Appendix F, Final plans and specifications: Final report

    SciTech Connect

    Not Available

    1991-11-01

    This volume deals with the main construction subcontract for the uranium mill tailings remedial action of Ambrosia Lake, New Mexico. Contents of subcontract documents AMB-4 include: bidding requirements; terms and conditions; specifications which cover general requirements and sitework; and subcontract drawings.

  1. Radiological surveillance of Remedial Action activities at the processing site, Ambrosia Lake, New Mexico, April 12--16, 1993. Final report

    SciTech Connect

    1993-04-01

    The Uranium Mill Tailings Remedial Action (UMTRA) Project`s Technical Assistance Contractor (TAC) performed a radiological surveillance of the Remedial Action Contractor (RAC), MK-Ferguson and CWM Federal Environmental Services, Inc., at the processing site in Ambrosia Lake, New Mexico. The requirements and attributes examined during the audit were developed from reviewing working-level procedures developed by the RAC. Objective evidence, comments, and observations were verified based on investigating procedures, documentation, records located at the site, personal interviews, and tours of the site. No findings were identified during this audit. Ten site-specific observations, three good practice observations, and five programmatic observations are presented in this report. The overall conclusion from the surveillance is that the radiological aspects of the Ambrosia Lake, New Mexico, remedial action program are performed adequately. The results of the good practice observations indicate that the site health physics (HP) staff is taking the initiative to address and resolve potential issues, and implement suggestions useful to the UMTRA Project. However, potential exists for improving designated storage areas for general items, and the RAC Project Office should consider resolving site-specific and procedural inconsistencies.

  2. Hydraulically integrated or modular? Comparing whole-plant-level hydraulic systems between two desert shrub species with different growth forms.

    PubMed

    Espino, Susana; Schenk, H Jochen

    2009-01-01

    * Hydraulic systems of shrubs vary between hydraulically integrated and modular architectures; the latter divide the shrub into independent hydraulic units. Hydraulic systems of two common North American desert shrub species, the multi-branched Ambrosia dumosa and the single-stemmed Encelia farinosa (both Asteraceae), were compared to test for division into independent hydraulic units and the implications of such a division for water loss through leaves and roots. * Hydraulic systems of mature shrubs in the field were characterized using dye tracers and by documenting the degree of stem segmentation. Young pot-grown shrubs were subjected to heterogeneous and homogeneous watering. Spatial within-canopy variation of leaf water potentials and stomatal conductances, as well as soil water contents, were measured in response to manipulated soil water heterogeneity. * Results show that young Ambrosia shrubs are divided into independent hydraulic units long before they physically split into separate ramets as mature shrubs, and that young and mature Encelia shrubs possess integrated hydraulic systems. No hydraulic redistribution was detected for eitherspecies. * Our study shows that functional segmentation into independent hydraulic units precedes physical axis splitting, rather than being the consequence of split axes, and suggests that mature shrubs with round basal stems are likely to be hydraulically integrated. PMID:19368668

  3. Using Square Roots

    ERIC Educational Resources Information Center

    Wilson, William Wynne

    1976-01-01

    This article describes techniques which enable the user of a comparatively simple calculator to perform calculations of cube roots, nth roots, trigonometric, and inverse trigonometric functions, logarithms, and exponentials. (DT)

  4. The Root Pressure Phenomenon

    ERIC Educational Resources Information Center

    Marsh, A. R.

    1972-01-01

    Describes experiments demonstrating that root pressure in plants is probably controlled by a circadian rhythm (biological clock). Root pressure phenomenon plays significant part in water transport in contradiction with prevalent belief. (PS)

  5. Corky root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corky root rot (corchosis) was first reported in Argentina in 1985, but the disease was presumably present long before that. The disease occurs in most alfalfa-growing areas of Argentina but is more common in older stands. In space-planted alfalfa trials scored for root problems, corky root rot was ...

  6. WHY ROOTING FAILS.

    SciTech Connect

    CREUTZ,M.

    2007-07-30

    I explore the origins of the unphysical predictions from rooted staggered fermion algorithms. Before rooting, the exact chiral symmetry of staggered fermions is a flavored symmetry among the four 'tastes.' The rooting procedure averages over tastes of different chiralities. This averaging forbids the appearance of the correct 't Hooft vertex for the target theory.

  7. Armillaria root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    First described on grapevines in California in the 1880s, Armillaria root rot occurs in all major grape-growing regions of the state. The causal fungus, Armillaria mellea, infects woody grapevine roots and the base of the trunk (the root collar), resulting in a slow decline and eventual death of the...

  8. BLACK ROOT ROT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Black Root Rot Prepared by G. S. Abawi, Revised by L.E. Hanson Black root rot is caused by Thielaviopsis basicola (syn. Chalara elegans). The pathogen is widely distributed, can infect more than 130 plant species in 15 families, and causes severe black root rot diseases in ornamentals and crops suc...

  9. Development of a simple PCR-based assay for the identification of triazine resistance in the noxious plant common ragweed (Ambrosia artemisiifolia) and its applicability in higher plants.

    PubMed

    Mátyás, Kinga Klára; Taller, János; Cseh, András; Poczai, Péter; Cernák, István

    2011-12-01

    Bidirectional allele-specific PCR (Bi-PASA) was used to detect a point mutation causing triazine resistance in common ragweed (Ambrosia artemisiifolia). The external primers amplified a 278 bp standard DNA fragment in all genotypes. In the susceptible S264S genotypes, a 208 bp fragment was expected while in resistant S264G common ragweed genotypes a 109 bp band was expected. In resistant plants, both the wild and mutant type fragments were detected, indicating that the original triazine sensitive cpDNA is maintained in a heteroplasmic state in the resistant S264G genotypes. Additionally, in silico analysis confirmed the potential applicability of our diagnostic assay for other plant species. In 24 out of 74 taxa (32%), the assay could be used without any change, while in the others some of the primers should be redesigned before use. PMID:21809088

  10. The impact of an invasive ambrosia beetle on the riparian habitats of the Tijuana River Valley, California

    PubMed Central

    2016-01-01

    The Tijuana River Valley is the first natural habitat in California to be substantially invaded by the Kuroshio Shot Hole Borer (KSHB, Euwallacea sp.), an ambrosia beetle native to Southeast Asia. This paper documents the distribution of the KSHB in the riparian vegetation in the valley and assesses the damage done to the vegetation as of early 2016, approximately six months after the beetle was first observed in the valley. I divided the riparian habitats into 29 survey units so that the vegetation within each unit was relatively homogenous in terms of plant species composition, age and density. From a random point within each unit, I examined approximately 60 individuals of the dominant plant species for evidence of KSHB infestation and evidence of major damage such as limb breakage. In the 22 forested units,I examined the dominant arroyo and black willows (Salix lasiolepis Benth. and S. gooddingii C.R. Ball), and in the seven scrub units, I examined mule fat (Baccharis salicifolia (Ruiz & Pav.) Pers.). Evidence of KSHB infestation was found in 25 of the 29 units. In the forest units, infestation rates ranged from 0 to 100% and were high (>60%) in 16 of the units. In the scrub units, infestation rates ranged from 0 to 33%. Infestation rates were significantly correlated with the wetness of a unit; wetter units had higher infestation rates. Evidence of major physical damage was found in 24 units, and dense stands of willows were reduced to broken trunks in several areas. Overall, I estimated that more than 280,000 (70%) of the willows in the valley were infested, and more than 140,000 had suffered major limb damage. In addition, I recorded evidence of KSHB infestation in the other common plant species in the valley; of the 23 species examined, 14 showed evidence of beetle attack. The four species with the highest rates of infestation were native trees in the Salicaceae family. The three species considered to be the worst invasive plants in the valley, Ricinus

  11. The impact of an invasive ambrosia beetle on the riparian habitats of the Tijuana River Valley, California.

    PubMed

    Boland, John M

    2016-01-01

    The Tijuana River Valley is the first natural habitat in California to be substantially invaded by the Kuroshio Shot Hole Borer (KSHB, Euwallacea sp.), an ambrosia beetle native to Southeast Asia. This paper documents the distribution of the KSHB in the riparian vegetation in the valley and assesses the damage done to the vegetation as of early 2016, approximately six months after the beetle was first observed in the valley. I divided the riparian habitats into 29 survey units so that the vegetation within each unit was relatively homogenous in terms of plant species composition, age and density. From a random point within each unit, I examined approximately 60 individuals of the dominant plant species for evidence of KSHB infestation and evidence of major damage such as limb breakage. In the 22 forested units,I examined the dominant arroyo and black willows (Salix lasiolepis Benth. and S. gooddingii C.R. Ball), and in the seven scrub units, I examined mule fat (Baccharis salicifolia (Ruiz & Pav.) Pers.). Evidence of KSHB infestation was found in 25 of the 29 units. In the forest units, infestation rates ranged from 0 to 100% and were high (>60%) in 16 of the units. In the scrub units, infestation rates ranged from 0 to 33%. Infestation rates were significantly correlated with the wetness of a unit; wetter units had higher infestation rates. Evidence of major physical damage was found in 24 units, and dense stands of willows were reduced to broken trunks in several areas. Overall, I estimated that more than 280,000 (70%) of the willows in the valley were infested, and more than 140,000 had suffered major limb damage. In addition, I recorded evidence of KSHB infestation in the other common plant species in the valley; of the 23 species examined, 14 showed evidence of beetle attack. The four species with the highest rates of infestation were native trees in the Salicaceae family. The three species considered to be the worst invasive plants in the valley, Ricinus

  12. Root canal irrigants

    PubMed Central

    Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

    2010-01-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are discussed. We performed a Medline search for English-language papers published untill July 2010. The keywords used were ‘root canal irrigants’ and ‘endodontic irrigants.’ The reference lists of each article were manually checked for additional articles of relevance. PMID:21217955

  13. The Ambrosia Lake project archaeological investigations of three small sites associated with the southern Chacoan outlier of Kin Nizhoni, McKinley County, New Mexico. [Uranium Mill Tailings Remedial Action (UMTRA) Project

    SciTech Connect

    Cullington, B.J.; Hammack, L.C.; Baugh, T.G. )

    1990-03-15

    During the fall of 1987, Complete Archaeological Service Associates conducted mitigative excavations at three sites (LA50363, LA50364, and LA50371) in McKinley County, New Mexico. These sites are adjacent to the Phillips/United Nuclear Inactive Uranium Mill and Tailings site at Ambrosia Lake, New Mexico. The primary deposition at each of these sites appears to be related to a Pueblo II or Bonito Phase occupation. Temporal placement is based primarily on the cross dating of ceramics and archaeomagnetic determinations when possible. No tree-ring or radiocarbon samples are available from these sites. These Ambrosia Lake sites indicate that this area was occupied primarily by Pueblo II people who may have had close social, economic, and ceremonial ties with the people living at the nuclear community of Lower Nizhoni about 3 km south-southeast. The later component at LA50364 indicates a Pueblo III occupation by people who may have had similar ties to the people of the Kin Nizhoni nuclear community. The Ambrosia Lake sites, then, provide important information on the structure of subnuclear communities within the southern Chaco periphery.

  14. The Roots of Literacy.

    ERIC Educational Resources Information Center

    Goodman, Yetta M.

    This review of research with children aged two to six on their reading, writing, and oral language development speaks of five roots of a tree of literate life that require nourishment in the soil of a written language environment. The roots discussed are the development of print awareness in situational contexts, the development of print awareness…

  15. Cylindrocarpon root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cylindrocarpon root rot of alfalfa has been found sporadically in Canada and the northern United States. The etiology of this disease is not fully understood, but the priority for research has not been high because of its infrequent occurrence. The infected area of the root initially has a water-soa...

  16. Irrational Square Roots

    ERIC Educational Resources Information Center

    Misiurewicz, Michal

    2013-01-01

    If students are presented the standard proof of irrationality of [square root]2, can they generalize it to a proof of the irrationality of "[square root]p", "p" a prime if, instead of considering divisibility by "p", they cling to the notions of even and odd used in the standard proof?

  17. Pythium Root Rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pythium root rot is a disease that is found in agricultural and nursery soils throughout the United States and Canada. It is caused by several Pythium species, and the symptoms are typified by leaf or needle chlorosis, stunting, root rot, and plant death. The disease is favored by wet soils, overc...

  18. Root-knot nematodes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although root-knot nematodes (Meloidogyne species) can reduce crop yields worldwide, methods for their identification are often difficult to implement. This review summarizes the diagnostic morphological and molecular features for distinguishing the ten major previously described root-knot nematode ...

  19. Trees and Roots.

    ERIC Educational Resources Information Center

    Jones, Lethonee A.

    Constructing a family history can be significant in helping persons understand and appreciate the root system that supports and sustains them. Oral history can be a valuable resource in family research as Alex Haley demonstrated in writing "Roots." The major difficulty of using oral tradition in tracing a family history is that family members with…

  20. Sugarbeet root aphid on postharvest root storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sugarbeet root aphid (SBRA), Pemphigus betae Doane, is a serious insect pest of sugarbeet in several North American sugarbeet production areas; however, it is rarely an economic pest in the Red River Valley (RRV). In 2012 and 2013, all RRV factory districts were impacted by SBRA outbreaks, and ...

  1. Root Nutrient Foraging1

    PubMed Central

    Giehl, Ricardo F.H.; von Wirén, Nicolaus

    2014-01-01

    During a plant's lifecycle, the availability of nutrients in the soil is mostly heterogeneous in space and time. Plants are able to adapt to nutrient shortage or localized nutrient availability by altering their root system architecture to efficiently explore soil zones containing the limited nutrient. It has been shown that the deficiency of different nutrients induces root architectural and morphological changes that are, at least to some extent, nutrient specific. Here, we highlight what is known about the importance of individual root system components for nutrient acquisition and how developmental and physiological responses can be coupled to increase nutrient foraging by roots. In addition, we review prominent molecular mechanisms involved in altering the root system in response to local nutrient availability or to the plant's nutritional status. PMID:25082891

  2. Factors controlling localization of uranium deposits in the Dakota Sandstone, Gallup and Ambrosia Lake mining districts, McKinley County, New Mexico

    USGS Publications Warehouse

    Pierson, Charles Thomas; Green, Morris W.

    1977-01-01

    Geologic studies were made at all of the uranium mines and prospects in the Dakota Sandstone of Early(?) and Late Cretaceous age in the Gallup mining district, McKinley County, New Mexico. Dakota mines in the adjacent Ambrosia Lake mining district were visited briefly for comparative purposes. Mines in the eastern part of the Gallup district, and in the Ambrosia Lake district, are on the Chaco slope of the southern San Juan Basin in strata which dip gently northward toward the central part of the basin. Mines in the western part of the Gallup district are along the Gallup hogback (Nutria monocline) in strata which dip steeply westward into the Gallup sag. Geologic factors which controlled formation of the uranium deposits in the Dakota Sandstone are: (1) a source of uranium, believed to be uranium deposits of the underlying Morrison Formation of Late Jurassic age; (2) the accessibility to the Dakota of uranium-bearing solutions from the Morrison; (3) the presence in the Dakota of permeable sandstone beds overlain by impermeable carbonaceous shale beds; and (4) the occurrence within the permeable Dakota sandstone beds of carbonaceous reducing material as bedding-plane laminae, or as pockets of carbonaceous trash. Most of the Dakota uranium deposits are found in the lower part of the formation in marginal-marine distributary-channel sandstones which were deposited in the backshore environment. However, the Hogback no. 4 (Hyde) Mine (Gallup district) occurs in sandy paludal shale of the backshore environment, and another deposit, the Silver Spur (Ambrosia Lake district), is found in what is interpreted to be a massive beach or barrier-bar sandstone of the foreshore environment in the upper part of the Dakota. The sedimentary depositional environment most favorable for the accumulation of uranium is that of backshore areas lateral to main distributary channels, where levee, splay, and some distributary-channel sandstones intertongue with gray carbonaceous shales and

  3. Economic strategies of plant absorptive roots vary with root diameter

    NASA Astrophysics Data System (ADS)

    Kong, D. L.; Wang, J. J.; Kardol, P.; Wu, H. F.; Zeng, H.; Deng, X. B.; Deng, Y.

    2016-01-01

    Plant roots typically vary along a dominant ecological axis, the root economics spectrum, depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root economic strategies differ with increasing root diameter. To test this hypothesis, we used seven plant species (a fern, a conifer, and five angiosperms from south China) for which we separated absorptive roots into two categories: thin roots (thickness of root cortex plus epidermis < 247 µm) and thick roots. For each category, we analyzed a range of root traits related to resource acquisition and conservation, including root tissue density, different carbon (C), and nitrogen (N) fractions (i.e., extractive, acid-soluble, and acid-insoluble fractions) as well as root anatomical traits. The results showed significant relationships among root traits indicating an acquisition-conservation tradeoff for thin absorptive roots while no such trait relationships were found for thick absorptive roots. Similar results were found when reanalyzing data of a previous study including 96 plant species. The contrasting economic strategies between thin and thick absorptive roots, as revealed here, may provide a new perspective on our understanding of the root economics spectrum.

  4. Quantitative measurements of root water uptake and root hydraulic conductivities

    NASA Astrophysics Data System (ADS)

    Zarebanadkouki, Mohsen; Javaux, Mathieu; Meunier, Felicien; Couvreur, Valentin; Carminati, Andrea

    2016-04-01

    How is root water uptake distributed along the root system and what root properties control this distribution? Here we present a method to: 1) measure root water uptake and 2) inversely estimate the root hydraulic conductivities. The experimental method consists in using neutron radiography to trace deuterated water (D2O) in soil and roots. The method was applied to lupines grown aluminium containers filled with a sandy soil. When the lupines were 4 weeks old, D2O was locally injected in a selected soil regions and its transport was monitored in soil and roots using time-series neutron radiography. By image processing, we quantified the concentration of D2O in soil and roots. We simulated the transport of D2O into roots using a diffusion-convection numerical model. The diffusivity of the roots tissue was inversely estimated by simulating the transport of D2O into the roots during night. The convective fluxes (i.e. root water uptake) were inversely estimating by fitting the experiments during day, when plants were transpiring, and assuming that root diffusivity did not change. The results showed that root water uptake was not uniform along the roots. Water uptake was higher at the proximal parts of the lateral roots and it decreased by a factor of 10 towards the distal parts. We used the data of water fluxes to inversely estimate the profile of hydraulic conductivities along the roots of transpiring plants growing in soil. The water fluxes in the lupine roots were simulated using the Hydraulic Tree Model by Doussan et al. (1998). The fitting parameters to be adjusted were the radial and axial hydraulic conductivities of the roots. The results showed that by using the root architectural model of Doussan et al. (1998) and detailed information of water fluxes into different root segments we could estimate the profile of hydraulic conductivities along the roots. We also found that: 1) in a tap-rooted plant like lupine water is mostly taken up by lateral roots; (2) water

  5. Roots in plant ecology.

    PubMed

    Cody, M L

    1986-09-01

    In 1727 the pioneer vegetation scientist Stephen Hales realized that I much that was of importance to his subject material took place below on ground. A good deal of descriptive work on plant roots and root systems was done in the subsequent two centuries; in crop plants especially, the gross morphology of root systems was well known by the early 20th century. These descriptive studies were extended to natural grasslands by Weaver and his associates and to deserts by Cannon by the second decade of this century, but since that time the study of subterranean growth form appears to have lapsed, as a recent review by Kummerow indicates. Nevertheless, growth form is an important aspect of plant ecology, and subterranean growth form is especially relevant to the study of vegetation in and areas (which is the main subject of this commentary). Moreover, there is a real need for more research to be directed towards understanding plant root systems in general. PMID:21227785

  6. Grass Rooting the System

    ERIC Educational Resources Information Center

    Perlman, Janice E.

    1976-01-01

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

  7. Reading with Roots

    ERIC Educational Resources Information Center

    Gibson, Margaret I.

    1986-01-01

    Recommends a method of teaching Russian vocabulary that focuses on new words in context and on their structure: root, prefix, suffix, sound changes, and borrowings. Sources for teachers are given in the bibliography. (LMO)

  8. The phenomenology of rooting.

    PubMed

    Kerievsky, Bruce Stephen

    2010-09-01

    This paper examines the attractions of passionate involvement in wanting particular outcomes, which is popularly known as rooting. The author's lifelong personal experience is the source of his analysis, along with the insights provided by spiritual literature and especially the work of Dr. Thomas Hora, with whom the author studied for 30 years. The phrase "choiceless awareness," utilized by J. Krishnamurti, and attained via meditation, is seen as the means of transcending a rooting mode of being in the world. PMID:20165983

  9. Modeling root reinforcement using root-failure Weibull survival function

    NASA Astrophysics Data System (ADS)

    Schwarz, M.; Giadrossich, F.; Cohen, D.

    2013-03-01

    Root networks contribute to slope stability through complicated interactions that include mechanical compression and tension. Due to the spatial heterogeneity of root distribution and the dynamic of root turnover, the quantification of root reinforcement on steep slope is challenging and consequently the calculation of slope stability as well. Although the considerable advances in root reinforcement modeling, some important aspect remain neglected. In this study we address in particular to the role of root strength variability on the mechanical behaviors of a root bundle. Many factors may contribute to the variability of root mechanical properties even considering a single class of diameter. This work presents a new approach for quantifying root reinforcement that considers the variability of mechanical properties of each root diameter class. Using the data of laboratory tensile tests and field pullout tests, we calibrate the parameters of the Weibull survival function to implement the variability of root strength in a numerical model for the calculation of root reinforcement (RBMw). The results show that, for both laboratory and field datasets, the parameters of the Weibull distribution may be considered constant with the exponent equal to 2 and the normalized failure displacement equal to 1. Moreover, the results show that the variability of root strength in each root diameter class has a major influence on the behavior of a root bundle with important implications when considering different approaches in slope stability calculation. Sensitivity analysis shows that the calibration of the tensile force and the elasticity of the roots are the most important equations, as well as the root distribution. The new model allows the characterization of root reinforcement in terms of maximum pullout force, stiffness, and energy. Moreover, it simplifies the implementation of root reinforcement in slope stability models. The realistic quantification of root reinforcement for

  10. The molecular basis of invasiveness: differences in gene expression of native and introduced common ragweed (Ambrosia artemisiifolia) in stressful and benign environments.

    PubMed

    Hodgins, Kathryn A; Lai, Zhao; Nurkowski, Kristin; Huang, Jie; Rieseberg, Loren H

    2013-05-01

    Although the evolutionary and ecological processes that contribute to plant invasion have been the focus of much research, investigation into the molecular basis of invasion is just beginning. Common ragweed (Ambrosia artemisiifolia) is an annual weed native to North America and has been introduced to Europe where it has become invasive. Using a custom-designed NimbleGen oligoarray, we examined differences in gene expression between five native and six introduced populations of common ragweed in three different environments (control, light stress and nutrient stress), as well as two different time points. We identified candidate genes that may contribute to invasiveness in common ragweed based on differences in expression between native and introduced populations from Europe. Specifically, we found 180 genes where range explained a significant proportion of the variation in gene expression and a further 103 genes with a significant range by treatment interaction. Several of these genes are potentially involved in the metabolism of secondary compounds, stress response and the detoxification of xenobiotics. Previously, we found more rapid growth and greater reproductive success in introduced populations, particularly in benign and competitive (light stress) environments, and many of these candidate genes potentially underlie these growth differences. We also found expression differences among populations within each range, reflecting either local adaptation or neutral processes, although no associations with climate or latitude were identified. These data provide a first step in identifying genes that are involved with introduction success in an aggressive annual weed. PMID:23294156

  11. Changes in defense of an alien plant Ambrosia artemisiifolia before and after the invasion of a native specialist enemy Ophraella communa.

    PubMed

    Fukano, Yuya; Yahara, Tetsukazu

    2012-01-01

    The evolution of increased competitive ability hypothesis (EICA) predicts that when alien plants are free from their natural enemies they evolve lower allocation to defense in order to achieve a higher growth rate. If this hypothesis is true, the converse implication would be that the defense against herbivory could be restored if a natural enemy also becomes present in the introduced range. We tested this scenario in the case of Ambrosia artemisiifolia (common ragweed) - a species that invaded Japan from North America. We collected seeds from five North American populations, three populations in enemy free areas of Japan and four populations in Japan where the specialist herbivore Ophraella communa naturalized recently. Using plants grown in a common garden in Japan, we compared performance of O. communa with a bioassay experiment. Consistent with the EICA hypothesis, invasive Japanese populations of A. artemisiifolia exhibited a weakened defense against the specialist herbivores and higher growth rate than native populations. Conversely, in locations where the herbivore O. communa appeared during the past decade, populations of A. artemisiifolia exhibited stronger defensive capabilities. These results strengthen the case for EICA and suggest that defense levels of alien populations can be recuperated rapidly after the native specialist becomes present in the introduced range. Our study implies that the plant defense is evolutionary labile depending on plant-herbivore interactions. PMID:23145089

  12. Estimating calibration equations for predicting Ra-226 soil concentrations using RTRAK in-situ detectors at the Ambrosia Lake, New Mexico, Umtra site

    SciTech Connect

    Gilbert, R. O.; Meyer, H. R.; Miller, M. L.; Begley, C.

    1988-06-01

    This report describes a field study conducted at the Ambrosia Lake, New Mexico, UMTRA site to obtain data for calibrating the RTRAK Sodium Iodide (NaI) detectors for estimating concentrations of Ra-226 in surface soil. The statistical analyses indicate that the data are useful for estimating the calibration equations. Several statistical models are used to evaluate which model is best as a basis for the calibration equations. A procedure is provided for using the estimated calibration equations and extensive RTRAK measurements to estimate the average Ra-226 concentration on 100-m/sup 2/ land areas to determine whether additional remedial action is needed. The UMTRA Project office proposes to use the RTRAK for cleanup verification of surface Ra-226 contamination. The system enables 100% coverage of areas having undergone remedial action. The sensitivity of the system enables verification at less than 5 pCi/g averaged over 100 m/sup 2/, as specified by the Environmental Protection Agency (EPA) standards (40 CFR Part 192). This analysis demonstrates RTRAK's ability to meet reasonable standards of statistical accuracy, using commonly accepted procedures. 5 refs., 8 figs., 1 tab.

  13. Impacts of a water stress followed by an early frost event on beech (Fagus sylvatica L.) susceptibility to Scolytine ambrosia beetles - Research strategy and first results

    NASA Astrophysics Data System (ADS)

    La Spina, Sylvie; de Cannière, Charles; Molenberg, Jean-Marc; Vincke, Caroline; Deman, Déborah; Grégoire, Jean-Claude

    2010-05-01

    Climate change tends to induce more frequent abiotic and biotic extreme events, having large impacts on tree vitality. Weakened trees are then more susceptible to secondary insect outbreaks, as it happened in Belgium in the early 2000s: after an early frost event, secondary Scolytine ambrosia beetles attacks were observed on beech trees. In this study, we test if a combination of stress, i.e. a soil water deficit preceding an early frost, could render trees more attractive to beetles. An experimental study was set in autumn 2008. Two parcels of a beech forest were covered with plastic tents to induce a water stress by rain interception. The parcels were surrounded by 2-meters depth trenches to avoid water supply by streaming. Soil water content and different indicators of tree water use (sap flow, predawn leaf water potential, tree radial growth) were followed. In autumn 2010, artificial frost injuries will be inflicted to trees using dry ice. Trees attractivity for Scolytine insects, and the success of insect colonization will then be studied. The poster will focus on experiment setting and first results (impacts of soil water deficit on trees).

  14. Predicting the potential distribution of invasive exotic species using GIS and information-theoretic approaches: A case of ragweed (Ambrosia artemisiifolia L.) distribution in China

    USGS Publications Warehouse

    Chen, H.; Chen, L.; Albright, T.P.

    2007-01-01

    Invasive exotic species pose a growing threat to the economy, public health, and ecological integrity of nations worldwide. Explaining and predicting the spatial distribution of invasive exotic species is of great importance to prevention and early warning efforts. We are investigating the potential distribution of invasive exotic species, the environmental factors that influence these distributions, and the ability to predict them using statistical and information-theoretic approaches. For some species, detailed presence/absence occurrence data are available, allowing the use of a variety of standard statistical techniques. However, for most species, absence data are not available. Presented with the challenge of developing a model based on presence-only information, we developed an improved logistic regression approach using Information Theory and Frequency Statistics to produce a relative suitability map. This paper generated a variety of distributions of ragweed (Ambrosia artemisiifolia L.) from logistic regression models applied to herbarium specimen location data and a suite of GIS layers including climatic, topographic, and land cover information. Our logistic regression model was based on Akaike's Information Criterion (AIC) from a suite of ecologically reasonable predictor variables. Based on the results we provided a new Frequency Statistical method to compartmentalize habitat-suitability in the native range. Finally, we used the model and the compartmentalized criterion developed in native ranges to "project" a potential distribution onto the exotic ranges to build habitat-suitability maps. ?? Science in China Press 2007.

  15. Changes in Defense of an Alien Plant Ambrosia artemisiifolia before and after the Invasion of a Native Specialist Enemy Ophraella communa

    PubMed Central

    Fukano, Yuya; Yahara, Tetsukazu

    2012-01-01

    The evolution of increased competitive ability hypothesis (EICA) predicts that when alien plants are free from their natural enemies they evolve lower allocation to defense in order to achieve a higher growth rate. If this hypothesis is true, the converse implication would be that the defense against herbivory could be restored if a natural enemy also becomes present in the introduced range. We tested this scenario in the case of Ambrosia artemisiifolia (common ragweed) – a species that invaded Japan from North America. We collected seeds from five North American populations, three populations in enemy free areas of Japan and four populations in Japan where the specialist herbivore Ophraella communa naturalized recently. Using plants grown in a common garden in Japan, we compared performance of O. communa with a bioassay experiment. Consistent with the EICA hypothesis, invasive Japanese populations of A. artemisiifolia exhibited a weakened defense against the specialist herbivores and higher growth rate than native populations. Conversely, in locations where the herbivore O. communa appeared during the past decade, populations of A. artemisiifolia exhibited stronger defensive capabilities. These results strengthen the case for EICA and suggest that defense levels of alien populations can be recuperated rapidly after the native specialist becomes present in the introduced range. Our study implies that the plant defense is evolutionary labile depending on plant-herbivore interactions. PMID:23145089

  16. Effect of chipping on emergence of the redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) and recovery of the laurel wilt pathogen from infested wood chips.

    PubMed

    Spence, D J; Smith, J A; Ploetz, R; Hulcr, J; Stelinski, L L

    2013-10-01

    Significant mortality ofredbay trees (Persea borbonia (L.) Spreng.) in the southeastern United States has been caused by Raffaelea lauricola, T.C. Harr., Fraedrich, & Aghayeva (Harrington et al. 2008), a fungal symbiont of the exotic redbay ambrosia beetle, Xyleborus glabratus, Eichhoff (Fraedrich et al. 2008). This pathogen causes laurel wilt, which is an irreversible disease that can kill mature trees within a few weeks in summer. R. lauricola has been shown to be lethal to most native species of Lauraceae and cultivated avocado (Persea americana Mill.) in the southeastern United States. In this study, we examined the survival of X. glabratus and R. lauricola in wood chips made from infested trees by using a standard tree chipper over a 10-wk period. After 2 wk, 14 X. glabratus were recovered from wood chips, whereas 339 X. glabratus emerged from nonchipped bolts. R. lauricola was not found 2 d postchipping from wood chips, indicating that the pathogen is not likely to survive for long inside wood chips. In contrast, R. lauricola persisted in dead, standing redbay trees for 14 mo. With large volumes of wood, the potential for infested logs to be moved between states or across U.S. borders is significant. Results demonstrated that chipping wood from laurel wilt-killed trees can significantly reduce the number of X. glabratus and limit the persistence of R. lauricola, which is important for sanitation strategies aimed at limiting the spread of this disease. PMID:24224251

  17. The "Green" Root Beer Laboratory

    ERIC Educational Resources Information Center

    Clary, Renee; Wandersee, James

    2010-01-01

    No, your students will not be drinking green root beer for St. Patrick's Day--this "green" root beer laboratory promotes environmental awareness in the science classroom, and provides a venue for some very sound science content! While many science classrooms incorporate root beer-brewing activities, the root beer lab presented in this article has…

  18. Final Technical Report

    SciTech Connect

    Donald L. Phillips; Mark G. Johnson, David T. Tingey

    2003-12-18

    OAK-B135 This study took place at the Nevada Desert FACE (Free Air CO2 Enrichment) Facility at the Nevada Test Site, where effects of elevated atmospheric CO2 on a desert ecosystem are being studied. One hundred sixty-eight minirhizotrons (clear plastic tubes) were installed to a depth of 1m in the soil in the control and elevated CO2 plots. Tubes were installed from a suspended platform to avoid soil compaction and disturbance. Tubes were placed under individuals of two dominant shrub species, Larrea tridentata and Ambrosia dumosa, and along systematic transects across the plots. Specialized video cameras were inserted down the tubes at 4 week intervals to provide images of plant root systems on the upper side of the tube. A ratcheting mechanism assured consistent imaging of the same precise locations during each sampling period. Images were collected every 4 weeks from December 1997 to January 2001, after which the images were too degraded from repeated camera abrasion on the tubes for adequate analysis. Over 100,000 video images were analyzed and the appearance, growth, and disappearance of 23,634 individual fine roots (<2 mm diameter) were tracked over time, totaling 125,679 root observations and measurements. Elevated CO2 did not have an effect on the timing of seasonal patterns of fine root growth or turnover (mortality). There were no consistent effects of elevated CO2 on fine root length standing crop, production, or turnover except standing crop was consistently lower under the elevated CO2 treatment across the community transects. The specific root length (m/g of root dry weight) found to be higher for Larrea and Ambrosia under elevated CO2 treatments. Procedures were developed to translate the length measurements taken from minirhizotron images to biomass estimates per unit soil volume, utilizing these specific root length measurements. While few differences in fine root length were apparent as a result of elevated CO2 treatment, conversion to biomass

  19. The root economics spectrum: divergence of absorptive root strategies with root diameter

    NASA Astrophysics Data System (ADS)

    Kong, D.; Wang, J.; Kardol, P.; Wu, H.; Zeng, H.; Deng, X.; Deng, Y.

    2015-08-01

    Plant roots usually vary along a dominant ecological axis, the root economics spectrum (RES), depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root strategies as predicted from the RES shift with increasing root diameter. To test this hypothesis, we used seven contrasting plant species for which we separated absorptive roots into two categories: thin roots (< 247 μm diameter) and thick roots. For each category, we analyzed a~range of root traits closely related to resource acquisition and conservation, including root tissue density, carbon (C) and nitrogen (N) fractions as well as root anatomical traits. The results showed that trait relationships for thin absorptive roots followed the expectations from the RES while no clear trait relationships were found in support of the RES for thick absorptive roots. Our results suggest divergence of absorptive root strategies in relation to root diameter, which runs against a single economics spectrum for absorptive roots.

  20. Root architecture and root and tuber crop productivity.

    PubMed

    Villordon, Arthur Q; Ginzberg, Idit; Firon, Nurit

    2014-07-01

    It is becoming increasingly evident that optimization of root architecture for resource capture is vital for enabling the next green revolution. Although cereals provide half of the calories consumed by humans, root and tuber crops are the second major source of carbohydrates globally. Yet, knowledge of root architecture in root and tuber species is limited. In this opinion article, we highlight what is known about the root system in root and tuber crops, and mark new research directions towards a better understanding of the relation between root architecture and yield. We believe that unraveling the role of root architecture in root and tuber crop productivity will improve global food security, especially in regions with marginal soil fertility and low-input agricultural systems. PMID:24630073

  1. Remedial action plan and site conceptual design for stabilization of the inactive uranium mill tailings site at Ambrosia Lake, New Mexico. Volume 1, Text, Appendices A, B, and C: Final report

    SciTech Connect

    Matthews, M.L.; Mitzelfelt, R.

    1991-11-01

    This Remedial Action Plan (RAP) has been developed to serve a dual purpose. It presents the series of activities that is proposed by the US Department of Energy (DOE) to stabilize and control radioactive materials at the inactive Phillips/United Nuclear uranium processing site designated as the Ambrosia Lake site in McKinley County, New Mexico. It also serves to document the concurrence of both State of New Mexico and the US Nuclear Regulatory Commission (NRC) in the remedial action. This agreement, upon execution by the DOE and the state and concurrence by NRC, becomes Appendix B of the Cooperative Agreement.

  2. Stachbotrys Root Rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stachybotrys root rot is caused by Stachybotrys chartarum, a cellulytic saprophytic hyphomycete fungus. The pathogen produces mycotoxins including a host of immunosupressant compounds for human and is one of the causes of the "sick building syndrome." Although S. chartarum is rarely known as a plan...

  3. Violet root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus causing violet root rot, Helicobasidium brebissonii (anamorph Rhizoctonia crocorum), is widely distributed in Europe and North America but is rarely of much economic importance on alfalfa. The disease has also been reported in Australia, Argentina, and Iran. The disease is characterized b...

  4. "Roots": Medium and Message.

    ERIC Educational Resources Information Center

    Kinnamon, Keneth

    A national telephone survey indicated that audiences rated the television production of "Roots" positively in terms of the following: realistic portrayal of the people and the times; relevance for contemporary race relations; perceived emotional effect; and increased understanding of the psychology of black people. However, a comparison of the…

  5. Great Plains Roots.

    ERIC Educational Resources Information Center

    Frey, Jennifer

    2001-01-01

    Sandy White Hawk, Sicangu Lakota, was adopted by white missionaries as an infant and suffered child abuse. After 33 years, she found her birth family and formed First Nations Orphans Association, which uses songs and ceremonies to help adoptees return to their roots. Until the 1970s, federal agencies and welfare organizations facilitated removal…

  6. The Roots of Reading.

    ERIC Educational Resources Information Center

    Montoya, Colleen, Ed.

    2002-01-01

    This newsletter covers educational issues affecting schools in the Western Regional Educational Laboratory's 4-state region (Arizona, California, Nevada, and Utah) and nationwide. The following articles appear in the Volume 4, Number 1 issue: (1) "The Roots of Reading"; (2) "Breaking the Code: Reading Literacy in K-3"; (3) "Improving Secondary…

  7. Effects of temperature on survival, development, longevity, and fecundity of Ophraella communa (Coleoptera: Chrysomelidae), a potential biological control agent against Ambrosia artemisiifolia (Asterales: Asteraceae).

    PubMed

    Zhou, Zhong-Shi; Guo, Jian-Ying; Chen, Hong-Song; Wan, Fang-Hao

    2010-06-01

    Ophraella communa (Coleoptera: Chrysomelidae) is a leaf beetle that is unintentionally introduced in China. It is a potential biological control agent against common ragweed, Ambrosia artemisiifolia (Asterales: Asteraceae). The effects of temperature on the development and fecundity of O. communa were studied at eight constant temperature regimens (15, 20, 22, 25, 28, 30, 32, 36 degrees C) in the laboratory. The results showed that the developmental periods for egg, larva, pupa, and entire immature stages decreased in response to the increasing temperature, with the exception of 30 degrees C. The survival rates at different developmental stages were higher at 25 and 28 degrees C than at other temperatures. Ovipositional period and longevity of female shortened with the increasing temperature. The highest fecundity of female was observed to be 2,712.3 eggs/female at 28 degrees C. Life table of O. communa was constructed based on the data at 20-32 degrees C. The innate capacity for increase (r(m)), the net reproductive rate (R(0)), and the finite rate of increase (lambda) reached the maximum at 28 degrees C, with values of 0.247, 1,773.0, and 1.280, respectively. The shortest period of a generation (T) was 24.6 d at 32 degrees C, whereas the longest T value was recorded as 79.3 d at 20 degrees C. These results offer valuable insight on the establishment potential of O. communa in new environments with diverse temperature regimens and on its mass-rearing techniques in laboratory. PMID:20550818

  8. Establishment and persistence of common ragweed (Ambrosia artemisiifolia L.) in disturbed soil as a function of an urban-rural macro-enviornment.

    SciTech Connect

    Lewis H. Ziska, Kate George, David A. Frenz

    2007-01-01

    No data are available on whether rising carbon dioxide concentration [CO2] or increased air temperature can alter the establishment and persistence of common ragweed (Ambrosia artemisiifolia L.) within a plant community following soil disturbance. To determine ragweed longevity, we exposed disturbed soil with a common seed bank population to an in situ temperature and [CO2] gradient along an urban-rural transect beginning in early 2002. No other consistent differences in meteorological variables (e.g. wind speed, humidity, PAR, tropospheric ozone) as a function of urbanization were documented over the course of the study (2002-2005). Above-ground measurements of biomass over this period demonstrated that ragweed along the transect responded to urban induced increases in [CO2]/temperature with peak biomass being observed at this location by the end of 2003. However, by the Fall of 2004, and continuing through 2005, urban ragweed populations had dwindled to a few plants. The temporal decline in ragweed populations was not associated with increased disease, herbivory or auto-allelopathy, but was part of a demographic reduction in the total number of annual plant species observed for the urban location. In a separate experiment, we showed that such a demographic shift is consistent with CO2/temperature induced increases in biomass and litter accumulation, with a subsequent reduction in germination / survival of annual plant species. Overall, these data indicate that [CO2]/temperature differences associated with urbanization may increase initial ragweed productivity and pollen production, but suggest that long-term, multi-year persistence of ragweed in the urban macro-environment may be dependent on other factors.

  9. Effect of trap type, trap position, time of year, and beetle density on captures of the redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae).

    PubMed

    Hanula, James L; Ulyshen, Michael D; Horn, Scott

    2011-04-01

    The exotic redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), and its fungal symbiont Raffaellea lauricola Harrington, Fraedrich, and Aghayeva are responsible for widespread redbay, Persea borbonia (L.) Spreng., mortality in the southern United States. Effective traps and lures are needed to monitor spread of the beetle and for early detection at ports-of-entry, so we conducted a series of experiments to find the best trap design, color, lure, and trap position for detection of X. glabratus. The best trap and lure combination was then tested at seven sites varying in beetle abundance and at one site throughout the year to see how season and beetle population affected performance. Manuka oil proved to be the most effective lure tested, particularly when considering cost and availability. Traps baited with manuka oil lures releasing 5 mg/d caught as many beetles as those baited with lures releasing 200 mg/d. Distributing manuka oil lures from the top to the bottom of eight-unit funnel traps resulted in similar numbers of X. glabratus as a single lure in the middle. Trap color had little effect on captures in sticky traps or cross-vane traps. Funnel traps caught twice as many beetles as cross-vane traps and three times as many as sticky traps but mean catch per trap was not significantly different. When comparing height, traps 1.5 m above the ground captured 85% of the beetles collected but a few were caught at each height up to 15 m. Funnel trap captures exhibited a strong linear relationship (r2 = 0.79) with X. glabratus attack density and they performed well throughout the year. Catching beetles at low densities is important to port of entry monitoring programs where early detection of infestations is essential. Our trials show that multiple funnel traps baited with a single manuka oil lure were effective for capturing X. glabratus even when no infested trees were visible in the area. PMID:21510198

  10. Investigating the relationship between Ambrosia pollen concentration and meteorological variables in a European domain based on CORDEX and CMIP5 simulations

    NASA Astrophysics Data System (ADS)

    Torma, Csaba Zsolt; Giorgi, Filippo

    2016-04-01

    As part of the European project, ATOPICA (atopic diseases in changing climate, land use & air quality) evaluation and scenario simulations were accomplished on 50-km grid spacing over a European domain which was defined in the framework of the international initiation called COordinated Regional Downscaling Experiment (CORDEX). Based on observational data collected from European pollen data bases, the pollen peak season of Ambrosia artemisiifolia L. (short or common ragweed) was found between the period: August-September (AS). One sub-region was selected (the most contaminated one: southern part of the Carpathian Basin) for further studies. Based on the ERA-Interim driven simulation of a regional climate model (RegCM) developed at the Abdus Salam International Centre of Theoretical Physics: temperature and precipitation indices are introduced related to the total common ragweed pollen concentration amounts over the target region for the period 1984-2008. In each case (temperature, precipitation) the index was based on the August-September (AS, peak-season) and June-July (JJ, pre-season) means by subtracting the latter from the previous one. The results manifested in a relatively clear signal between total pollen amounts and the indices. The temperature index is negatively, while the precipitation index is positively correlated with the total pollen amounts. This means cooler and wetter pre-seasonal and relatively drier and warmer peak-season weather conditions are favorable for the common ragweed outburst with high pollen concentrations. In total twenty global climate models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) and five regional climate models from the CORDEX initiative were involved in the analyses in order to assess the link between the indices and the seasonal total pollen amounts. The temperature and precipitation indices presented in this study can be a useful tool for seasonal pollen forecasting in future studies.

  11. Fine root turnover: a story of root production and root phenology

    NASA Astrophysics Data System (ADS)

    McCormack, M. L.; Adams, T. S.; Smithwick, E. A.; Eissenstat, D. M.

    2012-12-01

    Fine root turnover in terrestrial ecosystems partially controls carbon flow from plants into soils as well the amount of roots available for nutrient and water uptake. However, we have poor understanding of basic patterns and variability in fine root turnover. We address this shortfall through the use of a heuristic model and analysis of a multi-year minirhizotron dataset exploring the impacts of fine root phenology and production on fine root turnover rates across 12 temperate tree species in a common garden experiment. The heuristic model allowed us to calculate fine root turnover given different patterns of root production and different fine root lifespans. Using the model we found that patterns of phenology characterized by a single, concentrated peak resulted in slower calculated root turnover rates while broader and bi-modal production patterns resulted in faster turnover rates. For example, for roots with median lifespans of 91 days, estimates of root turnover increased from 1.5 yr-1 to 4.0 yr-1 between the pattern of concentrated root production and the pattern with root production spread equally throughout the year. Turnover rates observed in the common garden ranged from 0.75 yr-1 to 1.33 yr-1 and 0.93 yr-1 to 2.14 yr-1 when calculated as annual production divided by maximum standing root crop or average standing root crop, respectively. Turnover varied significantly across species and interannual variability in root production and turnover was high. Patterns of root phenology observed at the common garden included concentrated root production in late spring as well as several examples of bi-modal and broader patterns of root production with roots produced across spring, summer and fall. Overall, both phenology and total root production impacted estimates of root turnover, particularly for short-lived fine roots with median lifespans of less than one year. Our results suggest that better understanding fine root phenology and production will improve our

  12. The Physiology of Adventitious Roots.

    PubMed

    Steffens, Bianka; Rasmussen, Amanda

    2016-02-01

    Adventitious roots are plant roots that form from any nonroot tissue and are produced both during normal development (crown roots on cereals and nodal roots on strawberry [Fragaria spp.]) and in response to stress conditions, such as flooding, nutrient deprivation, and wounding. They are important economically (for cuttings and food production), ecologically (environmental stress response), and for human existence (food production). To improve sustainable food production under environmentally extreme conditions, it is important to understand the adventitious root development of crops both in normal and stressed conditions. Therefore, understanding the regulation and physiology of adventitious root formation is critical for breeding programs. Recent work shows that different adventitious root types are regulated differently, and here, we propose clear definitions of these classes. We use three case studies to summarize the physiology of adventitious root development in response to flooding (case study 1), nutrient deficiency (case study 2), and wounding (case study 3). PMID:26697895

  13. Hairy roots are more sensitive to auxin than normal roots

    PubMed Central

    Shen, Wen Hui; Petit, Annik; Guern, Jean; Tempé, Jacques

    1988-01-01

    Responses to auxin of Lotus corniculatus root tips or protoplasts transformed by Agrobacterium rhizogenes strains 15834 and 8196 were compared to those of their normal counterparts. Three different types of experiments were performed, involving long-term, medium-term, or short-term responses to a synthetic auxin, 1-naphthaleneacetic acid. Root tip elongation, proton excretion by root tips, and transmembrane electrical potential difference of root protoplasts were measured as a function of exogenous auxin concentration. The sensitivity of hairy root tips or protoplasts to exogenous auxin was found to be 100-1000 times higher than that of untransformed material. PMID:16593928

  14. Hairy roots are more sensitive to auxin than normal roots.

    PubMed

    Shen, W H; Petit, A; Guern, J; Tempé, J

    1988-05-01

    Responses to auxin of Lotus corniculatus root tips or protoplasts transformed by Agrobacterium rhizogenes strains 15834 and 8196 were compared to those of their normal counterparts. Three different types of experiments were performed, involving long-term, medium-term, or short-term responses to a synthetic auxin, 1-naphthaleneacetic acid. Root tip elongation, proton excretion by root tips, and transmembrane electrical potential difference of root protoplasts were measured as a function of exogenous auxin concentration. The sensitivity of hairy root tips or protoplasts to exogenous auxin was found to be 100-1000 times higher than that of untransformed material. PMID:16593928

  15. Root canal retained restorations: 3. Root-face attachments.

    PubMed

    Dummer, P M; Edmunds, D H; Gidden, J R

    1990-10-01

    It has been common practice for many years to use retained roots to provide support and stability for partial or full dentures. The retention of such overdentures is greatly enhanced if the remaining roots are modified and restored with posts and root-face attachments. The final article in this series on root canal retained restorations classifies and describes some of the root-face attachments currently available, and also describes a number of prefabricated post systems with integral overdenture attachments. Guidelines for clinical and laboratory procedures are given. PMID:2097234

  16. Strigolactones Effects on Root Growth

    NASA Astrophysics Data System (ADS)

    Koltai, Hinanit

    2012-07-01

    Strigolactones (SLs) were defined as a new group of plant hormones that suppress lateral shoot branching. Our previous studies suggested SLs to be regulators of root development. SLs were shown to alter root architecture by regulating lateral root formation and to affect root hair elongation in Arabidopsis. Another important effect of SLs on root growth was shown to be associated with root directional growth. Supplementation of SLs to roots led to alterations in root directional growth, whereas associated mutants showed asymmetrical root growth, which was influenced by environmental factors. The regulation by SLs of root development was shown to be conducted via a cross talk of SLs with other plant hormones, including auxin. SLs were shown to regulate auxin transport, and to interfere with the activity of auxin-efflux carriers. Therefore, it might be that SLs are regulators of root directional growth as a result of their ability to regulated auxin transport. However, other evidences suggest a localized effect of SLs on cell division, which may not necessarily be associated with auxin efflux. These and other, recent hypothesis as to the SLs mode of action and the associated root perception and response to environmental factors will be discussed.

  17. Aquaporins and root water relations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water is one of the most critical resources limiting plant growth and crop productivity, and root water uptake is an important aspect of plant physiology governing plant water use and stress tolerance. Pathways of root water uptake are complex and are affected by root structure and physiological res...

  18. Springback in root gravitropism

    NASA Technical Reports Server (NTRS)

    Leopold, A. C.; Wettlaufer, S. H.

    1989-01-01

    Conditions under which a gravistimulus of Merit corn roots (Zea mays L.) is withdrawn result in a subsequent loss of gravitropic curvature, an effect which we refer to as springback.' This loss of curvature begins within 1 to 10 minutes after removal of the gravistimulus. It occurs regardless of the presence or absence of the root cap. It is insensitive to inhibitors of auxin transport (2,3,5-triiodobenzoic acid, naphthylphthalamic [correction of naphthylphthalmaic] acid) or to added auxin (2,4-dichlorophenoxyacetic acid). Springback is prevented if a clinostat treatment is interjected to neutralize gravistimulation during germination, which suggests that the change in curvature is a response to a memory' effect carried over from a prior gravistimulation.

  19. Springback in root gravitropism.

    PubMed

    Leopold, A C; Wettlaufer, S H

    1989-01-01

    Conditions under which a gravistimulus of Merit corn roots (Zea mays L.) is withdrawn result in a subsequent loss of gravitropic curvature, an effect which we refer to as springback.' This loss of curvature begins within 1 to 10 minutes after removal of the gravistimulus. It occurs regardless of the presence or absence of the root cap. It is insensitive to inhibitors of auxin transport (2,3,5-triiodobenzoic acid, naphthylphthalamic [correction of naphthylphthalmaic] acid) or to added auxin (2,4-dichlorophenoxyacetic acid). Springback is prevented if a clinostat treatment is interjected to neutralize gravistimulation during germination, which suggests that the change in curvature is a response to a memory' effect carried over from a prior gravistimulation. PMID:11537456

  20. Diagravitropism in corn roots

    NASA Technical Reports Server (NTRS)

    Leopold, A. C.; Wettlaufer, S. H.

    1988-01-01

    The diagravitropic behavior of Merit corn (Zea mays L.) roots grown in darkness provides an opportunity for comparison of two qualitatively different gravitropic systems. As with positive gravitropism, diagravitropism is shown to require the presence of the root cap, have a similar time course for the onset of curvature, and a similar presentation time. In contrast with positive gravitropism, diagravitropism appears to have a more limited requirement for calcium, for it is insensitive to the elution of calcium by EGTA and insensitive to the subsequent addition of a calcium/EGTA complex. These results are interpreted as indicating that whereas the same sensing system is shared by the two types of gravitropism, separate transductive systems are involved, one for diagravitropism, which is relatively independent of calcium, and one for positive gravitropism, which is markedly dependent on calcium.

  1. Control of Arabidopsis Root Development

    PubMed Central

    Petricka, Jalean J.; Winter, Cara M.; Benfey, Philip N.

    2013-01-01

    The Arabidopsis root has been the subject of intense research over the past decades. This research has led to significantly improved understanding of the molecular mechanisms underlying root development. Key insights into the specification of individual cell types, cell patterning, growth and differentiation, branching of the primary root, and responses of the root to the environment have been achieved. Transcription factors and plant hormones play key regulatory roles. Recently, mechanisms involving protein movement and the oscillation of gene expression have also been uncovered. Root gene regulatory networks controlling root development have been reconstructed from genome-wide profiling experiments, revealing novel molecular connections and models. Future refinement of these models will lead to a more complete description of the complex molecular interactions that give rise to a simple growing root. PMID:22404466

  2. Origin of intraformational folds in the Jurassic Todilto Limestone, Ambrosia Lake uranium mining district, McKinley and Valencia counties, New Mexico

    USGS Publications Warehouse

    Green, M.W.

    1982-01-01

    The Todilto Limestone of Middle Jurassic age in the Ambrosia Lake uranium mining district of McKinley and Valencia Counties, New Mexico, is the host formation for numerous small- to medium-sized uranium deposits in joints, shear zones, and fractures within small- to large-scale intraformational folds. The folds probably were formed as a result of differential sediment loading when eolian sand dunes of the overlying Summerville Formation of Middle Jurassic age migrated over soft, chemically precipitated, lime muds of the Todilto shortly after their deposition in a regressive, mixed fresh and saline lacustrine or marine environment of deposition. Encroachment of Summerville eolian dunes over soft Todilto lime muds was apparently a local phenomenon and was restricted to postulated beltlike zones which trended radially across the Todilto coastline toward the receding body of water. Intraformational folding is believed to be confined to the pathways of individual eolian dunes or clusters of dunes within the dune belts. During the process of sediment loading by migrating sand dunes, layers of Todilto lime mud were differentially compacted, contorted, and dewatered, producing both small- and large-scale plastic deformation structures, including convolute laminations, mounds, rolls, folds, and small anticlines and synclines. With continued compaction and dewatering, the mud, in localized areas, reached a point of desaturation at which sediment plasticity was lost. Prolonged loading by overlying dune sands thus caused faulting, shearing, fracturing, and jointing of contorted limestone beds. These areas or zones of deformation within the limestone became the preferred sites of epigenetic uranium mineralization because of the induced transmissivity created by sediment rupture. Along most of the prograding Todilto coastline, adjacent to the eolian dune belts, both interdune and coastal sabkha environments dominated during Todilto-Summerville time. Sediments in coastal areas

  3. Biology and host associations of redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae), exotic vector of laurel wilt killing redbay trees in the southeastern United States.

    PubMed

    Hanula, James L; Mayfield, Albert E; Fraedrich, Stephen W; Rabaglia, Robert J

    2008-08-01

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), and its fungal symbiont, Raffaelea sp., are new introductions to the southeastern United States responsible for the wilt of mature redbay, Persea borbonia (L.) Spreng., trees. In 2006 and 2007, we investigated the seasonal flight activity of X. glabratus, its host associations, and population levels at eight locations in South Carolina and Georgia where infestations ranged from very recent to at least several years old. Adults were active throughout the year with peak activity in early September. Brood development seems to take 50-60 d. Wood infested with beetles and infected with the Raffaelea sp. was similar in attraction to uninfested redbay wood, whereas both were more attractive than a nonhost species. Sassafras, Sassafras albidium (Nutt.) Nees, another species of Lauraceae, was not attractive to X. glabratus and very few beetle entrance holes were found in sassafras wood compared with redbay. Conversely, avocado, Persea americana Mill., was as attractive to X. glabratus as swampbay, P. palustris (Raf.) Sarg., and both were more attractive than the nonhost red maple, Acer rubrum L. However, avocado had relatively few entrance holes in the wood. In 2007, we compared X. glabratus populations in areas where all mature redbay have died to areas where infestations were very active and more recent. Trap catches of X. glabratus and numbers of entrance holes in trap bolts of redbay were correlated with the number of dead trees with leaves attached. Older infestations where mature host trees had been eliminated by the wilt had low numbers of beetles resulting in trap catches ranging from 0.04 to 0.12 beetles per trap per d compared with 4-7 beetles per trap per d in areas with numerous recently dead trees. Our results indicate beetle populations drop dramatically after suitable host material is gone and provide hope that management strategies can be developed to restore

  4. The Roots of Beowulf

    NASA Technical Reports Server (NTRS)

    Fischer, James R.

    2014-01-01

    The first Beowulf Linux commodity cluster was constructed at NASA's Goddard Space Flight Center in 1994 and its origins are a part of the folklore of high-end computing. In fact, the conditions within Goddard that brought the idea into being were shaped by rich historical roots, strategic pressures brought on by the ramp up of the Federal High-Performance Computing and Communications Program, growth of the open software movement, microprocessor performance trends, and the vision of key technologists. This multifaceted story is told here for the first time from the point of view of NASA project management.

  5. Philosophical Roots of Cosmology

    NASA Astrophysics Data System (ADS)

    Ivanovic, M.

    2008-10-01

    We shall consider the philosophical roots of cosmology in the earlier Greek philosophy. Our goal is to answer the question: Are earlier Greek theories of pure philosophical-mythological character, as often philosophers cited it, or they have scientific character. On the bases of methodological criteria, we shall contend that the latter is the case. In order to answer the question about contemporary situation of the relation philosophy-cosmology, we shall consider the next question: Is contemporary cosmology completely independent of philosophical conjectures? The answer demands consideration of methodological character about scientific status of contemporary cosmology. We also consider some aspects of the relation contemporary philosophy-cosmology.

  6. Matching roots to their environment

    PubMed Central

    White, Philip J.; George, Timothy S.; Gregory, Peter J.; Bengough, A. Glyn; Hallett, Paul D.; McKenzie, Blair M.

    2013-01-01

    Background Plants form the base of the terrestrial food chain and provide medicines, fuel, fibre and industrial materials to humans. Vascular land plants rely on their roots to acquire the water and mineral elements necessary for their survival in nature or their yield and nutritional quality in agriculture. Major biogeochemical fluxes of all elements occur through plant roots, and the roots of agricultural crops have a significant role to play in soil sustainability, carbon sequestration, reducing emissions of greenhouse gasses, and in preventing the eutrophication of water bodies associated with the application of mineral fertilizers. Scope This article provides the context for a Special Issue of Annals of Botany on ‘Matching Roots to Their Environment’. It first examines how land plants and their roots evolved, describes how the ecology of roots and their rhizospheres contributes to the acquisition of soil resources, and discusses the influence of plant roots on biogeochemical cycles. It then describes the role of roots in overcoming the constraints to crop production imposed by hostile or infertile soils, illustrates root phenotypes that improve the acquisition of mineral elements and water, and discusses high-throughput methods to screen for these traits in the laboratory, glasshouse and field. Finally, it considers whether knowledge of adaptations improving the acquisition of resources in natural environments can be used to develop root systems for sustainable agriculture in the future. PMID:23821619

  7. Geophysical Imaging of Root Architecture and Root-soil Interaction

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Dafflon, B.; Hubbard, S. S.

    2015-12-01

    Roots play a critical role in controlling water and nutrient uptake, soil biogeochemical processes, as well as the physical anchorage for plants. While important processes, such as root hydraulic redistribution for optimal growth and survival have been recognized, representation of roots in climate models, e.g. its carbon storage, carbon resilience, root biomass, and role in regulating water and carbon fluxes across the rhizosphere and atmosphere interface is still challenging. Such a challenge is exacerbated because of the large variations of root architecture and function across species and locations due to both genetic and environmental controls and the lack of methods for quantifying root mass, distribution, dynamics and interaction with soils at field scales. The scale, complexity and the dynamic nature of plant roots call for minimally invasive methods capable of providing quantitative estimation of root architecture, dynamics over time and interactions with the soils. We present a study on root architecture and root-soil interactions using geophysical methods. Parameters and processes of interests include (1) moisture dynamics around root zone and its interaction with plant transpiration and environmental controls and (2) estimation of root structure and properties based on geophysical signals. Both pot and field scale studies were conducted. The pot scale experiments were conducted under controlled conditions and were monitored with cross-well electrical resistivity tomography (ERT), TDR moisture sensors and temperature probes. Pots with and without a tree were compared and the moisture conditions were controlled via a self regulated pumping system. Geophysical monitoring revealed interactions between roots and soils under dynamic soil moisture conditions and the role of roots in regulating the response of the soil system to changes of environmental conditions, e.g. drought and precipitation events. Field scale studies were conducted on natural trees using

  8. Perennial roots to immortality.

    PubMed

    Munné-Bosch, Sergi

    2014-10-01

    Maximum lifespan greatly varies among species, and it is not strictly determined; it can change with species evolution. Clonal growth is a major factor governing maximum lifespan. In the plant kingdom, the maximum lifespans described for clonal and nonclonal plants vary by an order of magnitude, with 43,600 and 5,062 years for Lomatia tasmanica and Pinus longaeva, respectively. Nonclonal perennial plants (those plants exclusively using sexual reproduction) also present a huge diversity in maximum lifespans (from a few to thousands of years) and even more interestingly, contrasting differences in aging patterns. Some plants show a clear physiological deterioration with aging, whereas others do not. Indeed, some plants can even improve their physiological performance as they age (a phenomenon called negative senescence). This diversity in aging patterns responds to species-specific life history traits and mechanisms evolved by each species to adapt to its habitat. Particularities of roots in perennial plants, such as meristem indeterminacy, modular growth, stress resistance, and patterns of senescence, are crucial in establishing perenniality and understanding adaptation of perennial plants to their habitats. Here, the key role of roots for perennial plant longevity will be discussed, taking into account current knowledge and highlighting additional aspects that still require investigation. PMID:24563283

  9. [Changes of root biomass, root surface area, and root length density in a Populus cathayana plantation].

    PubMed

    Yan, Hui; Liu, Guang-quan; Li, Hong-sheng

    2010-11-01

    By using soil core method, the biomass, surface area, and length density of roots < or =2 mm and 2-5 mm in diameter in a 50-year-old Populus cathayana plantation on the northern slope of Qinling Mountains were determined during growth season. Among the roots <5 mm in diameter, those < or =2 mm and 2-5 mm in diameter accounted for 77.8% and 22.2% of the total root biomass, respectively. The surface area and length density of the roots < or =2 mm in diameter accounted for more than 97% of the total, and those of the roots 2-5 mm in diameter only occupied less than 3%. The biomass, surface area, and root length density of roots < or =2 mm in diameter decreased with soil depth, while those of the roots 2-5 mm in diameter were the least in 20-30 cm soil layer. The biomass, surface area, and length density of roots < or =2 mm in diameter were significantly correlated with soil organic matter and available nitrogen, but no significant correlations were found for the roots 2-5 mm in diameter. PMID:21360997

  10. Transgene expression in regenerated roots.

    PubMed

    Malamy, Jocelyn

    2007-01-01

    INTRODUCTIONThis procedure, which uses a root transformation protocol, provides a rapid method for assessing gene expression in Arabidopsis roots. It is useful for testing promoter:reporter gene constructs, for expressing genes, the overexpression of which is lethal in whole plants, and for transforming the roots of plants that are recalcitrant to conventional transformation techniques. The protocol has been used successfully with Ws, No-0, and RLD ecotypes. PMID:21357026

  11. A Split-Root Technique for Measuring Root Water Potential

    PubMed Central

    Adeoye, Kingsley B.; Rawlins, Stephen L.

    1981-01-01

    Water encounters various resistances in moving along a path of decreasing potential energy from the soil through the plant to the atmosphere. The reported relative magnitudes of these pathway resistances vary widely and often these results are conflicting. One reason for such inconsistency is the difficulty in measuring the potential drop across various segments of the soil-plant-atmosphere continuum. The measurement of water potentials at the soil-root interface and in the root xylem of a transpiring plant remains a challenging problem. In the divided root experiment reported here, the measured water potential of an enclosed, nonabsorbing branch of the root system of young corn (Bonanza) plants to infer the water potential of the remaining roots growing in soil was used. The selected root branch of the seedling was grown in a specially constructed Teflon test tube into which a screen-enclosed thermocouple psychrometer was inserted and sealed to monitor the root's water potential. The root and its surrounding atmosphere were assumed to be in vapor equilibrium. Images PMID:16661886

  12. [A case of appendicular supplementary root with external root resorption].

    PubMed

    González Bahillo, J; Martínez Insua, A; Varela Patiño, P; Rivas Lombardero, P; Paz Pumpido, F

    1991-01-01

    The case of a lateral maxillary incisor with a supplementary root fractured by external root resorption, is presented. The role played for the periodontal disease is shown in the clinical and radiographic achievements, and their implications in the pulpal disease. Endodontic therapy was performed and the diagnosis confirmed in the specimen histological research. PMID:1858059

  13. The roots of predictivism.

    PubMed

    Barnes, Eric Christian

    2014-03-01

    In The Paradox of Predictivism (2008, Cambridge University Press) I tried to demonstrate that there is an intimate relationship between predictivism (the thesis that novel predictions sometimes carry more weight than accommodations) and epistemic pluralism (the thesis that one important form of evidence in science is the judgments of other scientists). Here I respond to various published criticisms of some of the key points from Paradox from David Harker, Jarret Leplin, and Clark Glymour. Foci include my account of predictive novelty (endorsement novelty), the claim that predictivism has two roots, the prediction per se and predictive success, and my account of why Mendeleev's predictions carried special weight in confirming the Periodic Law of the Elements. PMID:24984449

  14. New roots for agriculture: exploiting the root phenome

    PubMed Central

    Lynch, Jonathan P.; Brown, Kathleen M.

    2012-01-01

    Recent advances in root biology are making it possible to genetically design root systems with enhanced soil exploration and resource capture. These cultivars would have substantial value for improving food security in developing nations, where yields are limited by drought and low soil fertility, and would enhance the sustainability of intensive agriculture. Many of the phenes controlling soil resource capture are related to root architecture. We propose that a better understanding of the root phenome is needed to effectively translate genetic advances into improved crop cultivars. Elementary, unique root phenes need to be identified. We need to understand the ‘fitness landscape’ for these phenes: how they affect crop performance in an array of environments and phenotypes. Finally, we need to develop methods to measure phene expression rapidly and economically without artefacts. These challenges, especially mapping the fitness landscape, are non-trivial, and may warrant new research and training modalities. PMID:22527403

  15. Compensatory Root Water Uptake of Overlapping Root Systems

    NASA Astrophysics Data System (ADS)

    Agee, E.; Ivanov, V. Y.; He, L.; Bisht, G.; Shahbaz, P.; Fatichi, S.; Gough, C. M.; Couvreur, V.; Matheny, A. M.; Bohrer, G.

    2015-12-01

    Land-surface models use simplified representations of root water uptake based on biomass distributions and empirical functions that constrain water uptake during unfavorable soil moisture conditions. These models fail to capture the observed hydraulic plasticity that allows plants to regulate root hydraulic conductivity and zones of active uptake based on local gradients. Recent developments in root water uptake modeling have sought to increase its mechanistic representation by bridging the gap between physically based microscopic models and computationally feasible macroscopic approaches. It remains to be demonstrated whether bulk parameterization of microscale characteristics (e.g., root system morphology and root conductivity) can improve process representation at the ecosystem scale. We employ the Couvreur method of microscopic uptake to yield macroscopic representation in a coupled soil-root model. Using a modified version of the PFLOTRAN model, which represents the 3-D physics of variably saturated soil, we model a one-hectare temperate forest stand under natural and synthetic climatic forcing. Our results show that as shallow soil layers dry, uptake at the tree and stand level shift to deeper soil layers, allowing the transpiration stream demanded by the atmosphere. We assess the potential capacity of the model to capture compensatory root water uptake. Further, the hydraulic plasticity of the root system is demonstrated by the quick response of uptake to rainfall pulses. These initial results indicate a promising direction for land surface models in which significant three-dimensional information from large root systems can be feasibly integrated into the forest scale simulations of root water uptake.

  16. Determinants and Polynomial Root Structure

    ERIC Educational Resources Information Center

    De Pillis, L. G.

    2005-01-01

    A little known property of determinants is developed in a manner accessible to beginning undergraduates in linear algebra. Using the language of matrix theory, a classical result by Sylvester that describes when two polynomials have a common root is recaptured. Among results concerning the structure of polynomial roots, polynomials with pairs of…

  17. Cassava root membrane proteome reveals activities during storage root maturation.

    PubMed

    Naconsie, Maliwan; Lertpanyasampatha, Manassawe; Viboonjun, Unchera; Netrphan, Supatcharee; Kuwano, Masayoshi; Ogasawara, Naotake; Narangajavana, Jarunya

    2016-01-01

    Cassava (Manihot esculenta Crantz) is one of the most important crops of Thailand. Its storage roots are used as food, feed, starch production, and be the important source for biofuel and biodegradable plastic production. Despite the importance of cassava storage roots, little is known about the mechanisms involved in their formation. This present study has focused on comparison of the expression profiles of cassava root proteome at various developmental stages using two-dimensional gel electrophoresis and LC-MS/MS. Based on an anatomical study using Toluidine Blue, the secondary growth was confirmed to be essential during the development of cassava storage root. To investigate biochemical processes occurring during storage root maturation, soluble and membrane proteins were isolated from storage roots harvested from 3-, 6-, 9-, and 12-month-old cassava plants. The proteins with differential expression pattern were analysed and identified to be associated with 8 functional groups: protein folding and degradation, energy, metabolism, secondary metabolism, stress response, transport facilitation, cytoskeleton, and unclassified function. The expression profiling of membrane proteins revealed the proteins involved in protein folding and degradation, energy, and cell structure were highly expressed during early stages of development. Integration of these data along with the information available in genome and transcriptome databases is critical to expand knowledge obtained solely from the field of proteomics. Possible role of identified proteins were discussed in relation with the activities during storage root maturation in cassava. PMID:26547558

  18. Gravisensing in roots

    NASA Astrophysics Data System (ADS)

    Perbal, G.

    1999-01-01

    The mode of gravisensing in higher plants is not yet elucidated. Although, it is generally accepted that the amyloplasts (statoliths) in the root cap cells (statocytes) are responsible for susception of gravity. However, the hypothesis that the whole protoplast acts as gravisusceptor cannot be dismissed. The nature of the sensor that is able to transduce and amplify the mechanical energy into a biochemical factor is even more controversial. Several cell structures could potentially serve as gravireceptors: the endoplasmic reticulum, the actin network, the plasma membrane, or the cytoskeleton associated with this membrane. The nature of the gravisusceptors and gravisensors is discussed by taking into account the characteristics of the gravitropic reaction with respect to the presentation time, the threshold acceleration, the reciprocity rule, the deviation from the sine rule, the movement of the amyloplasts, the pre-inversion effect, the response of starch free and intermediate mutants and the effects of cytochalasin treatment. From this analysis, it can be concluded that both the amyloplasts and the protoplast could be the gravisusceptors, the former being more efficient than the latter since they can focus pressure on limited areas. The receptor should be located in the plasma membrane and could be a stretch-activated ion channel.

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

    NASA Astrophysics Data System (ADS)

    Salinas, A.; Zaharescu, D. G.

    2015-12-01

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

  20. Random root movements in weightlessness.

    PubMed

    Johnsson, A; Karlsson, C; Iversen, T H; Chapman, D K

    1996-02-01

    The dynamics of root growth was studied in weightlessness. In the absence of the gravitropic reference direction during weightlessness, root movements could be controlled by spontaneous growth processes, without any corrective growth induced by the gravitropic system. If truly random of nature, the bending behavior should follow so-called 'random walk' mathematics during weightlessness. Predictions from this hypothesis were critically tested. In a Spacelab ESA-experiment, denoted RANDOM and carried out during the IML-2 Shuttle flight in July 1994, the growth of garden cress (Lepidium sativum) roots was followed by time lapse photography at 1-h intervals. The growth pattern was recorded for about 20 h. Root growth was significantly smaller in weightlessness as compared to gravity (control) conditions. It was found that the roots performed spontaneous movements in weightlessness. The average direction of deviation of the plants consistently stayed equal to zero, despite these spontaneous movements. The average squared deviation increased linearly with time as predicted theoretically (but only for 8-10 h). Autocorrelation calculations showed that bendings of the roots, as determined from the 1-h photographs, were uncorrelated after about a 2-h interval. It is concluded that random processes play an important role in root growth. Predictions from a random walk hypothesis as to the growth dynamics could explain parts of the growth patterns recorded. This test of the hypothesis required microgravity conditions as provided for in a space experiment. PMID:11541141

  1. Nutritional regulation of root development.

    PubMed

    Ruiz Herrera, León Francisco; Shane, Michael W; López-Bucio, José

    2015-01-01

    Mineral nutrients such as nitrogen (N), phosphorus (P), and iron (Fe) are essential for plant growth, development, and reproduction. Adequate provision of nutrients via the root system impacts greatly on shoot biomass and plant productivity and is therefore of crucial importance for agriculture. Nutrients are taken up at the root surface in ionic form, which is mediated by specific transport proteins. Noteworthy, root tips are able to sense the local and internal concentrations of nutrients to adjust growth and developmental processes, and ultimately, to increase or decrease the exploratory capacity of the root system. Recently, important progress has been achieved in identifying the mechanisms of nutrient sensing in wild- and cultivated species, including Arabidopsis, bean, maize, rice, lupin as well as in members of the Proteaceae and Cyperaceae families, which develop highly sophisticated root clusters as adaptations to survive in soils with very low fertility. Major findings include identification of transporter proteins and transcription factors regulating nutrient sensing, miRNAs as mobile signals and peptides as repressors of lateral root development under heterogeneous nutrient supply. Understanding the roles played by N, P, and Fe in gene expression and biochemical characterization of proteins involved in root developmental responses to homogeneous or heterogeneous N and P sources has gained additional interest due to its potential for improving fertilizer acquisition efficiency in crops. PMID:25760021

  2. Hypocotyl adventitious root organogenesis differs from lateral root development

    PubMed Central

    Verstraeten, Inge; Schotte, Sébastien; Geelen, Danny

    2014-01-01

    Wound-induced adventitious root (AR) formation is a requirement for plant survival upon root damage inflicted by pathogen attack, but also during the regeneration of plant stem cuttings for clonal propagation of elite plant varieties. Yet, adventitious rooting also takes place without wounding. This happens for example in etiolated Arabidopsis thaliana hypocotyls, in which AR initiate upon de-etiolation or in tomato seedlings, in which AR initiate upon flooding or high water availability. In the hypocotyl AR originate from a cell layer reminiscent to the pericycle in the primary root (PR) and the initiated AR share histological and developmental characteristics with lateral roots (LRs). In contrast to the PR however, the hypocotyl is a determinate structure with an established final number of cells. This points to differences between the induction of hypocotyl AR and LR on the PR, as the latter grows indeterminately. The induction of AR on the hypocotyl takes place in environmental conditions that differ from those that control LR formation. Hence, AR formation depends on differentially regulated gene products. Similarly to AR induction in stem cuttings, the capacity to induce hypocotyl AR is genotype-dependent and the plant growth regulator auxin is a key regulator controlling the rooting response. The hormones cytokinins, ethylene, jasmonic acid, and strigolactones in general reduce the root-inducing capacity. The involvement of this many regulators indicates that a tight control and fine-tuning of the initiation and emergence of AR exists. Recently, several genetic factors, specific to hypocotyl adventitious rooting in A. thaliana, have been uncovered. These factors reveal a dedicated signaling network that drives AR formation in the Arabidopsis hypocotyl. Here we provide an overview of the environmental and genetic factors controlling hypocotyl-born AR and we summarize how AR formation and the regulating factors of this organogenesis are distinct from LR

  3. IAA transport in corn roots includes the root cap

    SciTech Connect

    Hasenstein, K.H. )

    1989-04-01

    In earlier reports we concluded that auxin is the growth regulator that controls gravicurvature in roots and that the redistribution of auxin occurs within the root cap. Since other reports did not detect auxin in the root cap, we attempted to confirm the IAA does move through the cap. Agar blocks containing {sup 3}H-IAA were applied to the cut surface of 5 mm long apical segments of primary roots of corn (mo17xB73). After 30 to 120 min radioactivity (RA) of the cap and root tissue was determined. While segments suspended in water-saturated air accumulated very little RA in the cap, application of 0.5 {mu}1 of dist. water to the cap (=controls) increased RA of the cap dramatically. Application to the cap of 0.5 {mu}1 of sorbitol or the Ca{sup 2+} chelator EGTA reduced cap RA to 46% and 70% respectively compared to water, without affecting uptake. Control root segments gravireacted faster than non-treated or osmoticum or EGTA treated segments. The data indicate that both the degree of hydration and calcium control the amount of auxin moving through the cap.

  4. Towards a multidimensional root trait framework: a tree root review.

    PubMed

    Weemstra, Monique; Mommer, Liesje; Visser, Eric J W; van Ruijven, Jasper; Kuyper, Thomas W; Mohren, Godefridus M J; Sterck, Frank J

    2016-09-01

    Contents 1159 I. 1159 II. 1161 III. 1164 IV. 1166 1167 References 1167 SUMMARY: The search for a root economics spectrum (RES) has been sparked by recent interest in trait-based plant ecology. By analogy with the one-dimensional leaf economics spectrum (LES), fine-root traits are hypothesised to match leaf traits which are coordinated along one axis from resource acquisitive to conservative traits. However, our literature review and meta-level analysis reveal no consistent evidence of an RES mirroring an LES. Instead the RES appears to be multidimensional. We discuss three fundamental differences contributing to the discrepancy between these spectra. First, root traits are simultaneously constrained by various environmental drivers not necessarily related to resource uptake. Second, above- and belowground traits cannot be considered analogues, because they function differently and might not be related to resource uptake in a similar manner. Third, mycorrhizal interactions may offset selection for an RES. Understanding and explaining the belowground mechanisms and trade-offs that drive variation in root traits, resource acquisition and plant performance across species, thus requires a fundamentally different approach than applied aboveground. We therefore call for studies that can functionally incorporate the root traits involved in resource uptake, the complex soil environment and the various soil resource uptake mechanisms - particularly the mycorrhizal pathway - in a multidimensional root trait framework. PMID:27174359

  5. Root hairs improve root penetration, root-soil contact, and phosphorus acquisition in soils of different strength.

    PubMed

    Haling, Rebecca E; Brown, Lawrie K; Bengough, A Glyn; Young, Iain M; Hallett, Paul D; White, Philip J; George, Timothy S

    2013-09-01

    Root hairs are a key trait for improving the acquisition of phosphorus (P) by plants. However, it is not known whether root hairs provide significant advantage for plant growth under combined soil stresses, particularly under conditions that are known to restrict root hair initiation or elongation (e.g. compacted or high-strength soils). To investigate this, the root growth and P uptake of root hair genotypes of barley, Hordeum vulgare L. (i.e. genotypes with and without root hairs), were assessed under combinations of P deficiency and high soil strength. Genotypes with root hairs were found to have an advantage for root penetration into high-strength layers relative to root hairless genotypes. In P-deficient soils, despite a 20% reduction in root hair length under high-strength conditions, genotypes with root hairs were also found to have an advantage for P uptake. However, in fertilized soils, root hairs conferred an advantage for P uptake in low-strength soil but not in high-strength soil. Improved root-soil contact, coupled with an increased supply of P to the root, may decrease the value of root hairs for P acquisition in high-strength, high-P soils. Nevertheless, this work demonstrates that root hairs are a valuable trait for plant growth and nutrient acquisition under combined soil stresses. Selecting plants with superior root hair traits is important for improving P uptake efficiency and hence the sustainability of agricultural systems. PMID:23861547

  6. Power and Roots by Recursion.

    ERIC Educational Resources Information Center

    Aieta, Joseph F.

    1987-01-01

    This article illustrates how questions from elementary finance can serve as motivation for studying high order powers, roots, and exponential functions using Logo procedures. A second discussion addresses a relatively unknown algorithm for the trigonometric exponential and hyperbolic functions. (PK)

  7. Ultrasonic cleaning of root canals

    NASA Astrophysics Data System (ADS)

    Verhaagen, Bram; Boutsioukis, Christos; Jiang, Lei-Meng; Macedo, Ricardo; van der Sluis, Luc; Versluis, Michel

    2011-11-01

    A crucial step during a dental root canal treatment is irrigation, where an antimicrobial fluid is injected into the root canal system to eradicate all bacteria. Agitation of the fluid using an ultrasonically vibrating miniature file has shown significant improvement in cleaning efficacy over conventional syringe irrigation. However, the physical mechanisms underlying the cleaning process, being acoustic streaming, cavitation or chemical activity, and combinations thereof, are not fully understood. High-speed imaging allows us to visualize the flow pattern and cavitation in a root canal model at microscopic scales, at timescales relevant to the cleaning processes (microseconds). MicroPIV measurements of the induced acoustic streaming are coupled to the oscillation characteristics of the file as simulated numerically and measured with a laser vibrometer. The results give new insight into the role of acoustic streaming and the importance of the confinement for the cleaning of root canals.

  8. Root Patterns in Heterogeneous Soils

    NASA Astrophysics Data System (ADS)

    Dara, A.; Moradi, A. B.; Carminati, A.; Oswald, S. E.

    2010-12-01

    Heterogeneous water availability is a typical characteristic of soils in which plant roots grow. Despite the intrinsic heterogeneity of soil-plant water relations, we know little about the ways how plants respond to local environmental quality. Furthermore, increasing use of soil amendments as partial water reservoirs in agriculture calls for a better understanding of plant response to soil heterogeneity. Neutron radiography is a non-invasive imaging that is highly sensitive to water and root distribution and that has high capability for monitoring spatial and temporal soil-plant water relations in heterogeneous systems. Maize plants were grown in 25 x 30 x 1 cm aluminum slabs filled with sandy soil. On the right side of the compartments a commercial water absorbent (Geohumus) was mixed with the soil. Geohumus was distributed with two patterns: mixed homogeneously with the soil, and arranged as 1-cm diameter aggregates (Fig. 1). Two irrigation treatments were applied: sufficient water irrigation and moderate water stress. Neutron radiography started 10 days after planting and has been performed twice a day for one week. At the end of the experiment, the containers were opened, the root were removed and dry root weight in different soil segments were measured. Neutron radiography showed root growth tendency towards Geohumus treated parts and preferential water uptake from Geohumus aggregates. Number and length of fine lateral roots were lower in treated areas compared to the non-treated zone and to control soil. Although corn plants showed an overall high proliferation towards the soil water sources, they decreased production of branches and fine root when water was more available near the main root parts. However there was 50% higher C allocation in roots grown in Geohumus compartments, as derived by the relative dry weight of root. The preferential C allocation in treated regions was higher when plants grew under water stress. We conclude that in addition to the

  9. Root Caries in Older Adults.

    PubMed

    Gregory, Dick; Hyde, Susan

    2015-08-01

    Older adults are retaining an increasing number of natural teeth, and nearly half of all individuals aged 75 and older have experienced root caries. Root caries is a major cause of tooth loss in older adults, and tooth loss is the most significant negative impact on oral health-related quality of life for the elderly. The need for improved preventive efforts and treatment strategies for this population is acute. PMID:26357814

  10. Effect of parameter choice in root water uptake models - the arrangement of root hydraulic properties within the root architecture affects dynamics and efficiency of root water uptake

    NASA Astrophysics Data System (ADS)

    Bechmann, M.; Schneider, C.; Carminati, A.; Vetterlein, D.; Attinger, S.; Hildebrandt, A.

    2014-10-01

    Detailed three-dimensional models of root water uptake have become increasingly popular for investigating the process of root water uptake. However, they suffer from a lack of information on important parameters, particularly on the spatial distribution of root axial and radial conductivities, which vary greatly along a root system. In this paper we explore how the arrangement of those root hydraulic properties and branching within the root system affects modelled uptake dynamics, xylem water potential and the efficiency of root water uptake. We first apply a simple model to illustrate the mechanisms at the scale of single roots. By using two efficiency indices based on (i) the collar xylem potential ("effort") and (ii) the integral amount of unstressed root water uptake ("water yield"), we show that an optimal root length emerges, depending on the ratio between roots axial and radial conductivity. Young roots with high capacity for radial uptake are only efficient when they are short. Branching, in combination with mature transport roots, enables soil exploration and substantially increases active young root length at low collar potentials. Second, we investigate how this shapes uptake dynamics at the plant scale using a comprehensive three-dimensional root water uptake model. Plant-scale dynamics, such as the average uptake depth of entire root systems, were only minimally influenced by the hydraulic parameterization. However, other factors such as hydraulic redistribution, collar potential, internal redistribution patterns and instantaneous uptake depth depended strongly on the arrangement on the arrangement of root hydraulic properties. Root systems were most efficient when assembled of different root types, allowing for separation of root function in uptake (numerous short apical young roots) and transport (longer mature roots). Modelling results became similar when this heterogeneity was accounted for to some degree (i.e. if the root systems contained between

  11. Plant root-microbe communication in shaping root microbiomes.

    PubMed

    Lareen, Andrew; Burton, Frances; Schäfer, Patrick

    2016-04-01

    A growing body of research is highlighting the impacts root-associated microbial communities can have on plant health and development. These impacts can include changes in yield quantity and quality, timing of key developmental stages and tolerance of biotic and abiotic stresses. With such a range of effects it is clear that understanding the factors that contribute to a plant-beneficial root microbiome may prove advantageous. Increasing demands for food by a growing human population increases the importance and urgency of understanding how microbiomes may be exploited to increase crop yields and reduce losses caused by disease. In addition, climate change effects may require novel approaches to overcoming abiotic stresses such as drought and salinity as well as new emerging diseases. This review discusses current knowledge on the formation and maintenance of root-associated microbial communities and plant-microbe interactions with a particular emphasis on the effect of microbe-microbe interactions on the shape of microbial communities at the root surface. Further, we discuss the potential for root microbiome modification to benefit agriculture and food production. PMID:26729479

  12. Root anatomical phenes predict root penetration ability and biomechanical properties in maize (Zea Mays)

    PubMed Central

    Chimungu, Joseph G.; Loades, Kenneth W.; Lynch, Jonathan P.

    2015-01-01

    The ability of roots to penetrate hard soil is important for crop productivity but specific root phenes contributing to this ability are poorly understood. Root penetrability and biomechanical properties are likely to vary in the root system dependent on anatomical structure. No information is available to date on the influence of root anatomical phenes on root penetrability and biomechanics. Root penetration ability was evaluated using a wax layer system. Root tensile and bending strength were evaluated in plant roots grown in the greenhouse and in the field. Root anatomical phenes were found to be better predictors of root penetrability than root diameter per se and associated with smaller distal cortical region cell size. Smaller outer cortical region cells play an important role in stabilizing the root against ovalization and reducing the risk of local buckling and collapse during penetration, thereby increasing root penetration of hard layers. The use of stele diameter was found to be a better predictor of root tensile strength than root diameter. Cortical thickness, cortical cell count, cortical cell wall area and distal cortical cell size were stronger predictors of root bend strength than root diameter. Our results indicate that root anatomical phenes are important predictors for root penetrability of high-strength layers and root biomechanical properties. PMID:25903914

  13. How Can Science Education Foster Students' Rooting?

    ERIC Educational Resources Information Center

    Østergaard, Edvin

    2015-01-01

    The question of how to foster rooting in science education points towards a double challenge; efforts to "prevent" (further) uprooting and efforts to "promote" rooting/re-rooting. Wolff-Michael Roth's paper discusses the uprooting/rooting pair of concepts, students' feeling of alienation and loss of fundamental sense of the…

  14. MES Buffer Affects Arabidopsis Root Apex Zonation and Root Growth by Suppressing Superoxide Generation in Root Apex

    PubMed Central

    Kagenishi, Tomoko; Yokawa, Ken; Baluška, František

    2016-01-01

    In plants, growth of roots and root hairs is regulated by the fine cellular control of pH and reactive oxygen species (ROS). MES, 2-(N-morpholino)ethanesulfonic acid as one of the Good’s buffers has broadly been used for buffering medium, and it is thought to suit for plant growth with the concentration at 0.1% (w/v) because the buffer capacity of MES ranging pH 5.5–7.0 (for Arabidopsis, pH 5.8). However, many reports have shown that, in nature, roots require different pH values on the surface of specific root apex zones, namely meristem, transition zone, and elongation zone. Despite the fact that roots always grow on a media containing buffer molecule, little is known about impact of MES on root growth. Here, we have checked the effects of different concentrations of MES buffer using growing roots of Arabidopsis thaliana. Our results show that 1% of MES significantly inhibited root growth, the number of root hairs and length of meristem, whereas 0.1% promoted root growth and root apex area (region spanning from the root tip up to the transition zone). Furthermore, superoxide generation in root apex disappeared at 1% of MES. These results suggest that MES disturbs normal root morphogenesis by changing the ROS homeostasis in root apex. PMID:26925066

  15. MES Buffer Affects Arabidopsis Root Apex Zonation and Root Growth by Suppressing Superoxide Generation in Root Apex.

    PubMed

    Kagenishi, Tomoko; Yokawa, Ken; Baluška, František

    2016-01-01

    In plants, growth of roots and root hairs is regulated by the fine cellular control of pH and reactive oxygen species (ROS). MES, 2-(N-morpholino)ethanesulfonic acid as one of the Good's buffers has broadly been used for buffering medium, and it is thought to suit for plant growth with the concentration at 0.1% (w/v) because the buffer capacity of MES ranging pH 5.5-7.0 (for Arabidopsis, pH 5.8). However, many reports have shown that, in nature, roots require different pH values on the surface of specific root apex zones, namely meristem, transition zone, and elongation zone. Despite the fact that roots always grow on a media containing buffer molecule, little is known about impact of MES on root growth. Here, we have checked the effects of different concentrations of MES buffer using growing roots of Arabidopsis thaliana. Our results show that 1% of MES significantly inhibited root growth, the number of root hairs and length of meristem, whereas 0.1% promoted root growth and root apex area (region spanning from the root tip up to the transition zone). Furthermore, superoxide generation in root apex disappeared at 1% of MES. These results suggest that MES disturbs normal root morphogenesis by changing the ROS homeostasis in root apex. PMID:26925066

  16. Root traits for infertile soils

    PubMed Central

    White, Philip J.; George, Timothy S.; Dupuy, Lionel X.; Karley, Alison J.; Valentine, Tracy A.; Wiesel, Lea; Wishart, Jane

    2013-01-01

    Crop production is often restricted by the availability of essential mineral elements. For example, the availability of N, P, K, and S limits low-input agriculture, the phytoavailability of Fe, Zn, and Cu limits crop production on alkaline and calcareous soils, and P, Mo, Mg, Ca, and K deficiencies, together with proton, Al and Mn toxicities, limit crop production on acid soils. Since essential mineral elements are acquired by the root system, the development of crop genotypes with root traits increasing their acquisition should increase yields on infertile soils. This paper examines root traits likely to improve the acquisition of these elements and observes that, although the efficient acquisition of a particular element requires a specific set of root traits, suites of traits can be identified that benefit the acquisition of a group of mineral elements. Elements can be divided into three Groups based on common trait requirements. Group 1 comprises N, S, K, B, and P. Group 2 comprises Fe, Zn, Cu, Mn, and Ni. Group 3 contains mineral elements that rarely affect crop production. It is argued that breeding for a limited number of distinct root ideotypes, addressing particular combinations of mineral imbalances, should be pursued. PMID:23781228

  17. Electrotropism of Maize Roots 1

    PubMed Central

    Ishikawa, Hideo; Evans, Michael L.

    1990-01-01

    We examined the kinetics of electrotropic curvature in solutions of low electrolyte concentration using primary roots of maize (Zea mays L., variety Merit). When submerged in oxygenated solution across which an electric field was applied, the roots curved rapidly and strongly toward the positive electrode (anode). The strength of the electrotropic response increased and the latent period decreased with increasing field strength. At a field strength of 7.5 volts per centimeter the latent period was 6.6 minutes and curvature reached 60 degrees in about 1 hour. For electric fields greater than 10 volts per centimeter the latent period was less than 1 minute. There was no response to electric fields less than 2.8 volts per centimeter. Both electrotropism and growth were inhibited when indoleacetic acid (10 micromolar) was included in the medium. The auxin transport inhibitor pyrenoylbenzoic acid strongly inhibited electrotropism without inhibiting growth. Electrotropism was enhanced by treatments that interfere with gravitropism, e.g. decapping the roots or pretreating them with ethyleneglycol-bis-[β-ethylether]-N,N,N′,N′-tetraacetic acid. Similarly, roots of agravitropic pea (Pisum sativum, variety Ageotropum) seedlings were more responsive to electrotropic stimulation than roots of normal (variety Alaska) seedlings. The data indicate that the early steps of gravitropism and electrotropism occur by independent mechanisms. However, the motor mechanisms of the two responses may have features in common since auxin and auxin transport inhibitors reduced both gravitropism and electrotropism. PMID:11537481

  18. Magnetophoretic Induction of Root Curvature

    NASA Technical Reports Server (NTRS)

    Hasenstein, Karl H.

    1997-01-01

    The last year of the grant period concerned the consolidation of previous experiments to ascertain that the theoretical premise apply not just to root but also to shoots. In addition, we verified that high gradient magnetic fields do not interfere with regular cellular activities. Previous results have established that: (1) intracellular magnetophoresis is possible; and (2) HGMF lead to root curvature. In order to investigate whether HGMF affect the assembly and/or organization of structural proteins, we examined the arrangement of microtubules in roots exposed to HGMF. The cytoskeletal investigations were performed with fomaldehyde-fixed, nonembedded tissue segments that were cut with a vibratome. Microtubules (MTs) were stained with rat anti-yeast tubulin (YOL 1/34) and DTAF-labeled antibody against rat IgG. Microfilaments (MFs) were visualized by incubation in rhodamine-labeled phalloidin. The distribution and arrangement of both components of the cytoskeleton were examined with a confocal microscope. Measurements of growth rates and graviresponse were done using a video-digitizer. Since HGMF repel diamagnetic substances including starch-filled amyloplasts and most The second aspect of the work includes studies of the effect of cytoskeletal inhibitors on MTs and MFs. The analysis of the effect of micotubular inhibitors on the auxin transport in roots showed that there is very little effect of MT-depolymerizing or stabilizing drugs on auxin transport. This is in line with observations that application of such drugs is not immediately affecting the graviresponsiveness of roots.

  19. Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster

    PubMed Central

    Danjon, Frédéric; Caplan, Joshua S.; Fortin, Mathieu; Meredieu, Céline

    2013-01-01

    Root systems of woody plants generally display a strong relationship between the cross-sectional area or cross-sectional diameter (CSD) of a root and the dry weight of biomass (DWd) or root volume (Vd) that has grown (i.e., is descendent) from a point. Specification of this relationship allows one to quantify root architectural patterns and estimate the amount of material lost when root systems are extracted from the soil. However, specifications of this relationship generally do not account for the fact that root systems are comprised of multiple types of roots. We assessed whether the relationship between CSD and Vd varies as a function of root type. Additionally, we sought to identify a more accurate and time-efficient method for estimating missing root volume than is currently available. We used a database that described the 3D root architecture of Pinus pinaster root systems (5, 12, or 19 years) from a stand in southwest France. We determined the relationship between CSD and Vd for 10,000 root segments from intact root branches. Models were specified that did and did not account for root type. The relationships were then applied to the diameters of 11,000 broken root ends to estimate the volume of missing roots. CSD was nearly linearly related to the square root of Vd, but the slope of the curve varied greatly as a function of root type. Sinkers and deep roots tapered rapidly, as they were limited by available soil depth. Distal shallow roots tapered gradually, as they were less limited spatially. We estimated that younger trees lost an average of 17% of root volume when excavated, while older trees lost 4%. Missing volumes were smallest in the central parts of root systems and largest in distal shallow roots. The slopes of the curves for each root type are synthetic parameters that account for differentiation due to genetics, soil properties, or mechanical stimuli. Accounting for this differentiation is critical to estimating root loss accurately. PMID

  20. Efficient hydraulic properties of root systems

    NASA Astrophysics Data System (ADS)

    Bechmann, Marcel; Schneider, Christoph; Carminati, Andrea; Hildebrandt, Anke

    2013-04-01

    Understanding the mechanisms of ecosystem root water uptake (RWU) is paramount for parameterizing hydrological models. With the increase in computational power it is possible to calculate RWU explicitly up to the single plant scale using physical models. However, application of these models for increasing our understanding of ecosystem root water uptake is hindered by the deficit in knowledge about the detailed hydraulic parameter distribution within root systems. However, those physical models may help us to identify efficient parameterizations and to describe the influence of these hydraulic parameters on RWU profiles. In this research, we investigated the combined influence of root hydraulic parameters and different root topologies on shaping efficient root water uptake. First, we use a conceptual model of simple branching structures to understand the influence of branching location and transitions in root hydraulic properties on the RWU patterns in typical sub root structures. Second, we apply a physical model called "aRoot" to test our conclusions on complex root system architectures of single plants. aRoot calculates the distribution of xylem potential within arbitrary root geometries to satisfy a given water demand depending on the available water in the soil. Redistribution of water within the bulk soil is calculated using the Richards equation. We analyzed results using a measure of uptake efficiency, which describes the effort necessary for transpiration. Simulations with the conceptual model showed that total transpiration in sub root structures is independent of root hydraulic properties over a wide range of hydraulic parameters. On the other hand efficiency of root water uptake depends crucially on distribution hydraulic parameters in line with root topology. At the same time, these parameters shape strongly the distribution of RWU along the roots, and its evolution in time, thus leading to variable individual root water uptake profiles. Calculating

  1. Sensitivity of the "Root Bundle Model" to root mechanical properties and root distribution: Implication for shallow landslide stability.

    NASA Astrophysics Data System (ADS)

    Schwarz, Massimiliano; Giadrossich, Filippo; Cohen, Denis

    2015-04-01

    Root reinforcement is recognized as an important factor for shallow landslides stability. Due to the complexity of root reinforcement mechanisms and the heterogeneity of the root-soil system, the estimation of parameters used in root reinforcement models is difficult, time consuming, and often highly uncertain. For practical applications, it is necessary to focus on the estimation of the most relevant parameters. The objective of the present contribution is to review the state of the art in the development of root reinforcement models and to discuss the sensitivity of the "Root Bundle Model" (RBM) when considering the variability of root mechanical properties and the heterogeneity of root distributions. The RBM is a strain-step loading fiber bundle model extended to include the mechanical and geometrical properties of roots. The model allows the calculation of the force-displacement behavior of a root bundle. In view of new results of field pullout tests performed on coarse roots of spruce (Picea abies) and considering a consistent dataset of root distribution of alpine tree species, we quantify the sensitivity of the RBM and the uncertainty associated with the most important input parameters. Preliminary results show that the extrapolation of force-diameter values from incomplete datasets (i.e., when only small roots are tested and values for coarse roots are extrapolated) may result in considerable errors. In particular, in the case of distributions with root diameters larger than 5 mm, root reinforcement tends to be dominated by coarse roots and their mechanical properties need to be quantified. In addition to the results of the model sensitivity, we present a possible best-practice method for the quantification of root reinforcement in view of its application to slope stability calculations and implementations in numerical models.

  2. Root branching: mechanisms, robustness, and plasticity.

    PubMed

    Dastidar, Mouli Ghosh; Jouannet, Virginie; Maizel, Alexis

    2012-01-01

    Plants are sessile organisms that must efficiently exploit their habitat for water and nutrients. The degree of root branching impacts the efficiency of water uptake, acquisition of nutrients, and anchorage. The root system of plants is a dynamic structure whose architecture is determined by modulation of primary root growth and root branching. This plasticity relies on the continuous integration of environmental inputs and endogenous developmental programs controlling root branching. This review focuses on the cellular and molecular mechanisms involved in the regulation of lateral root distribution, initiation, and organogenesis with the main focus on the root system of Arabidopsis thaliana. We also examine the mechanisms linking environmental changes to the developmental pathways controlling root branching. Recent progress that emphasizes the parallels to the formation of root branches in other species is discussed. PMID:23801487

  3. New theories of root growth modelling

    NASA Astrophysics Data System (ADS)

    Landl, Magdalena; Schnepf, Andrea; Vanderborght, Jan; Huber, Katrin; Javaux, Mathieu; Bengough, A. Glyn; Vereecken, Harry

    2016-04-01

    In dynamic root architecture models, root growth is represented by moving root tips whose line trajectory results in the creation of new root segments. Typically, the direction of root growth is calculated as the vector sum of various direction-affecting components. However, in our simulations this did not reproduce experimental observations of root growth in structured soil. We therefore developed a new approach to predict the root growth direction. In this approach we distinguish between, firstly, driving forces for root growth, i.e. the force exerted by the root which points in the direction of the previous root segment and gravitropism, and, secondly, the soil mechanical resistance to root growth or penetration resistance. The latter can be anisotropic, i.e. depending on the direction of growth, which leads to a difference between the direction of the driving force and the direction of the root tip movement. Anisotropy of penetration resistance can be caused either by microscale differences in soil structure or by macroscale features, including macropores. Anisotropy at the microscale is neglected in our model. To allow for this, we include a normally distributed random deflection angle α to the force which points in the direction of the previous root segment with zero mean and a standard deviation σ. The standard deviation σ is scaled, so that the deflection from the original root tip location does not depend on the spatial resolution of the root system model. Similarly to the water flow equation, the direction of the root tip movement corresponds to the water flux vector while the driving forces are related to the water potential gradient. The analogue of the hydraulic conductivity tensor is the root penetrability tensor. It is determined by the inverse of soil penetration resistance and describes the ease with which a root can penetrate the soil. By adapting the three dimensional soil and root water uptake model R-SWMS (Javaux et al., 2008) in this way

  4. Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

    NASA Technical Reports Server (NTRS)

    Ng, Y. K.; Moore, R.

    1985-01-01

    The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

  5. Four cuspal maxillary second premolar with single root and three root canals: Case report

    PubMed Central

    Bansal, Parul; Nikhil, Vineeta; Goyal, Ayush; Singh, Ritu

    2016-01-01

    Traditional configuration of maxillary second premolars has been described to have two cusps, one root and one or two root canals. The endodontic literature reports considerable anatomic aberrations in the root canal morphology of maxillary second premolar but the literature available on the variation in cuspal anatomy and its relationship to the root canal anatomy is sparse. The purpose of this clinical report was to describe the root and root canal configuration of a maxillary second premolar with four cusps. PMID:27563190

  6. Four cuspal maxillary second premolar with single root and three root canals: Case report.

    PubMed

    Bansal, Parul; Nikhil, Vineeta; Goyal, Ayush; Singh, Ritu

    2016-01-01

    Traditional configuration of maxillary second premolars has been described to have two cusps, one root and one or two root canals. The endodontic literature reports considerable anatomic aberrations in the root canal morphology of maxillary second premolar but the literature available on the variation in cuspal anatomy and its relationship to the root canal anatomy is sparse. The purpose of this clinical report was to describe the root and root canal configuration of a maxillary second premolar with four cusps. PMID:27563190

  7. Brown Root Rot of Alfalfa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This bulletin describes the disease of alfalfa called brown root rot (BRR) including: the disease symptoms, the fungal pathogen and its biology, its distribution, and disease management. Since the 1920s, BRR has been regarded as an important disease of forage legumes, including alfalfa, in northern ...

  8. Dry root rot of chickpea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dry root rot of chickpea is a serious disease under dry hot summer conditions, particularly in the semi-arid tropics of Ethiopia, and in central and southern India. It usually occurs at reproductive stages of the plant. Symptoms include drooping of petioles and leaflets of the tips, but not the low...

  9. Rhizoctonia root rot of lentil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root rot is a soilborne disease of lentil caused by the fungal pathogen Rhizoctonia solani, and is favored by cool (11-19 C or 52 - 66 F) and wet soil conditions. The disease starts as reddish or dark brown lesions on lentil plants near the soil line, and develops into sunken lesions an...

  10. [Root arthrosis of the thumb].

    PubMed

    Hautefeuille, P; Duquesnoy, B

    1991-12-15

    Root arthrosis of the thumb results from a degenerative lesion of the trapezometacarpal joint. It is particularly frequent in menopausal women. The often prolonged pain it produces sometimes raises therapeutic problems. Treatment is always medical at first, but when it fails several surgical operations will ensure permanent painlessness. PMID:1808686

  11. Disease notes - Bacterial root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial root rot initiated by lactic acid bacteria, particularly Leuconostoc, occurs every year in Idaho sugarbeet fields. Hot fall weather seems to make the problem worse. Although Leuconostoc initiates the rot, other bacteria and yeast frequently invade the tissue as well. The acetic acid bac...

  12. Cutting the Roots of Violence.

    ERIC Educational Resources Information Center

    Koziey, Paul W.

    1996-01-01

    Violence is rooted in obedience to authority and in comparisons--foundations of our institutions of parenting and schooling. Obedience brings reward and punishment, comparison perpetuates a cycle of competition and conflict. Television violence is especially harmful because children easily understand visual images. The Reality Research approach to…

  13. Excising the Root from STEM

    ERIC Educational Resources Information Center

    Lock, Roger

    2009-01-01

    There are a number of well-intentioned STEM initiatives, some designed to improve the recruitment and retention of science teachers. Sometimes it appears that the initiators are remote from direct contact with the "grass roots" issues that feed the "stem" on which the blossoms of young enthusiastic recruits to the science teaching profession are…

  14. Molecular regulatory mechanism of tooth root development

    PubMed Central

    Huang, Xiao-Feng; Chai, Yang

    2012-01-01

    The root is crucial for the physiological function of the tooth, and a healthy root allows an artificial crown to function as required clinically. Tooth crown development has been studied intensively during the last few decades, but root development remains not well understood. Here we review the root development processes, including cell fate determination, induction of odontoblast and cementoblast differentiation, interaction of root epithelium and mesenchyme, and other molecular mechanisms. This review summarizes our current understanding of the signaling cascades and mechanisms involved in root development. It also sets the stage for de novo tooth regeneration. PMID:23222990

  15. Characterizing pathways by which gravitropic effectors could move from the root cap to the root of primary roots of Zea mays

    NASA Technical Reports Server (NTRS)

    Moore, R.; McClelen, C. E.

    1989-01-01

    Plasmodesmata linking the root cap and root in primary roots Zea mays are restricted to approx. 400 protodermal cells bordering approx. 110000 microns2 of the calyptrogen of the root cap. This area is less than 10% of the cross-sectional area of the root-tip at the cap junction. Therefore, gravitropic effectors moving from the root cap to the root can move symplastically only through a relatively small area in the centre of the root. Decapped roots are non-responsive to gravity. However, decapped roots whose caps are replaced immediately after decapping are strongly graviresponsive. Thus, gravicurvature occurs only when the root cap contacts the root, and symplastic continuity between the cap and root is not required for gravicurvature. Completely removing mucilage from the root tip renders the root non-responsive to gravity. Taken together, these data suggest that gravitropic effectors move apoplastically through mucilage from the cap to the root.

  16. Investigation of VEGGIE Root Mat

    NASA Technical Reports Server (NTRS)

    Subbiah, Arun M.

    2013-01-01

    VEGGIE is a plant growth facility that utilizes the phenomenon of capillary action as its primary watering system. A cloth made of Meta Aramid fiber, known as Nomex is used to wick water up from a reservoir to the bottom of the plants roots. This root mat system is intended to be low maintenance with no moving parts and requires minimal crew interface time. Unfortunately, the water wicking rates are inconsistent throughout the plant life cycle, thus causing plants to die. Over-wicking of water occurs toward the beginning of the cycle, while under-wicking occurs toward the middle. This inconsistency of wicking has become a major issue, drastically inhibiting plant growth. The primary objective is to determine the root cause of the inconsistent wicking through experimental testing. Suspect causes for the capillary water column to break include: a vacuum effect due to a negative pressure gradient in the water reservoir, contamination of material due to minerals in water and back wash from plant fertilizer, induced air bubbles while using syringe refill method, and material limitations of Nomex's ability to absorb and retain water. Experimental testing will be conducted to systematically determine the cause of under and over-wicking. Pressure gages will be used to determine pressure drop during the course of the plant life cycle and during the water refill process. A debubbler device will be connected to a root mat in order to equalize pressure inside the reservoir. Moisture and evaporation tests will simultaneously be implemented to observe moisture content and wicking rates over the course of a plant cycle. Water retention tests will be performed using strips of Nomex to determine materials wicking rates, porosity, and absorptivity. Through these experimental tests, we will have a better understanding of material properties of Nomex, as well as determine the root cause of water column breakage. With consistent test results, a forward plan can be achieved to resolve

  17. Control of root system architecture by DEEPER ROOTING 1 increases rice yield under drought conditions.

    PubMed

    Uga, Yusaku; Sugimoto, Kazuhiko; Ogawa, Satoshi; Rane, Jagadish; Ishitani, Manabu; Hara, Naho; Kitomi, Yuka; Inukai, Yoshiaki; Ono, Kazuko; Kanno, Noriko; Inoue, Haruhiko; Takehisa, Hinako; Motoyama, Ritsuko; Nagamura, Yoshiaki; Wu, Jianzhong; Matsumoto, Takashi; Takai, Toshiyuki; Okuno, Kazutoshi; Yano, Masahiro

    2013-09-01

    The genetic improvement of drought resistance is essential for stable and adequate crop production in drought-prone areas. Here we demonstrate that alteration of root system architecture improves drought avoidance through the cloning and characterization of DEEPER ROOTING 1 (DRO1), a rice quantitative trait locus controlling root growth angle. DRO1 is negatively regulated by auxin and is involved in cell elongation in the root tip that causes asymmetric root growth and downward bending of the root in response to gravity. Higher expression of DRO1 increases the root growth angle, whereby roots grow in a more downward direction. Introducing DRO1 into a shallow-rooting rice cultivar by backcrossing enabled the resulting line to avoid drought by increasing deep rooting, which maintained high yield performance under drought conditions relative to the recipient cultivar. Our experiments suggest that control of root system architecture will contribute to drought avoidance in crops. PMID:23913002

  18. Nicotiana Roots Recruit Rare Rhizosphere Taxa as Major Root-Inhabiting Microbes.

    PubMed

    Saleem, Muhammad; Law, Audrey D; Moe, Luke A

    2016-02-01

    Root-associated microbes have a profound impact on plant health, yet little is known about the distribution of root-associated microbes among different root morphologies or between rhizosphere and root environments. We explore these issues here with two commercial varieties of burley tobacco (Nicotiana tabacum) using 16S rRNA gene amplicon sequencing from rhizosphere soil, as well as from primary, secondary, and fine roots. While rhizosphere soils exhibited a fairly rich and even distribution, root samples were dominated by Proteobacteria. A comparison of abundant operational taxonomic units (OTUs) between rhizosphere and root samples indicated that Nicotiana roots select for rare taxa (predominantly Proteobacteria, Verrucomicrobia, Actinobacteria, Bacteroidetes, and Acidobacteria) from their corresponding rhizosphere environments. The majority of root-inhabiting OTUs (~80 %) exhibited habitat generalism across the different root morphological habitats, although habitat specialists were noted. These results suggest a specific process whereby roots select rare taxa from a larger community. PMID:26391804

  19. The role of strigolactones in root development

    PubMed Central

    Sun, Huwei; Tao, Jinyuan; Gu, Pengyuan; Xu, Guohua; Zhang, Yali

    2016-01-01

    Strigolactones (SLs) and their derivatives were recently defined as novel phytohormones that orchestrate shoot and root growth. Levels of SLs, which are produced mainly by plant roots, increase under low nitrogen and phosphate levels to regulate plant responses. Here, we summarize recent work on SL biology by describing their role in the regulation of root development and hormonal crosstalk during root deve-lopment. SLs promote the elongation of seminal/primary roots and adventitious roots (ARs) and they repress lateral root formation. In addition, auxin signaling acts downstream of SLs. AR formation is positively or negatively regulated by SLs depending largely on the plant species and experimental conditions. The relationship between SLs and auxin during AR formation appears to be complex. Most notably, this hormonal response is a key adaption that radically alters rice root architecture in response to nitrogen- and phosphate-deficient conditions. PMID:26515106

  20. Environmental Control of Root System Biology.

    PubMed

    Rellán-Álvarez, Rubén; Lobet, Guillaume; Dinneny, José R

    2016-04-29

    The plant root system traverses one of the most complex environments on earth. Understanding how roots support plant life on land requires knowing how soil properties affect the availability of nutrients and water and how roots manipulate the soil environment to optimize acquisition of these resources. Imaging of roots in soil allows the integrated analysis and modeling of environmental interactions occurring at micro- to macroscales. Advances in phenotyping of root systems is driving innovation in cross-platform-compatible methods for data analysis. Root systems acclimate to the environment through architectural changes that act at the root-type level as well as through tissue-specific changes that affect the metabolic needs of the root and the efficiency of nutrient uptake. A molecular understanding of the signaling mechanisms that guide local and systemic signaling is providing insight into the regulatory logic of environmental responses and has identified points where crosstalk between pathways occurs. PMID:26905656

  1. Rhizosphere biophysics and root water uptake

    NASA Astrophysics Data System (ADS)

    Carminati, Andrea; Zarebanadkouki, Mohsen; Ahmed, Mutez A.; Passioura, John

    2016-04-01

    The flow of water into the roots and the (putative) presence of a large resistance at the root-soil interface have attracted the attention of plant and soil scientists for decades. Such resistance has been attributed to a partial contact between roots and soil, large gradients in soil matric potential around the roots, or accumulation of solutes at the root surface creating a negative osmotic potential. Our hypothesis is that roots are capable of altering the biophysical properties of the soil around the roots, the rhizosphere, facilitating root water uptake in dry soils. In particular, we expect that root hairs and mucilage optimally connect the roots to the soil maintaining the hydraulic continuity across the rhizosphere. Using a pressure chamber apparatus we measured the relation between transpiration rate and the water potential difference between soil and leaf xylem during drying cycles in barley mutants with and without root hairs. The samples were grown in well structured soils. At low soil moistures and high transpiration rates, large drops in water potential developed around the roots. These drops in water potential recovered very slowly, even after transpiration was severely decreased. The drops in water potential were much bigger in barley mutants without root hairs. These mutants failed to sustain high transpiration rates in dry conditions. To explain the nature of such drops in water potential across the rhizosphere we performed high resolution neutron tomography of the rhizosphere of the barleys with and without root hairs growing in the same soil described above. The tomograms suggested that the hydraulic contact between the soil structures was the highest resistance for the water flow in dry conditions. The tomograms also indicate that root hairs and mucilage improved the hydraulic contact between roots and soil structures. At high transpiration rates and low water contents, roots extracted water from the rhizosphere, while the bulk soil, due its

  2. Single-rooted primary first mandibular molar

    PubMed Central

    Haridoss, SelvaKumar; Swaminathan, Kavitha; Rajendran, Vijayakumar; Rajendran, Bharathan

    2014-01-01

    Morphological variations like single-rooted molar in primary dentition are scarce. Understanding the root canal anatomy and variations is necessary for successful root canal therapy. The purpose of the present article is to report successful endodontic treatment of primary left mandibular first molar with an abnormal morphology of a single root. This case report highlights the importance of knowledge and its applications in the management of anomalous anatomic variants which play a crucial role in the success of endodontic treatment. PMID:25150245

  3. Root proliferation in decaying roots and old root channels: A nutrient conservation mechanism in oligotrophic mangrove forests?

    USGS Publications Warehouse

    McKee, K.L.

    2001-01-01

    1. In oligotrophic habitats, proliferation of roots in nutrient-rich microsites may contribute to overall nutrient conservation by plants. Peat-based soils on mangrove islands in Belize are characterized by the presence of decaying roots and numerous old root channels (0.1-3.5 cm diameter) that become filled with living and highly branched roots of Rhizophora mangle and Avicennia germinans. The objectives of this study were to quantify the proliferation of roots in these microsites and to determine what causes this response. 2. Channels formed by the refractory remains of mangrove roots accounted for only 1-2% of total soil volume, but the proportion of roots found within channels varied from 9 to 24% of total live mass. Successive generations of roots growing inside increasingly smaller root channels were also found. 3. When artificial channels constructed of PVC pipe were buried in the peat for 2 years, those filled with nutrient-rich organic matter had six times more roots than empty or sand-filled channels, indicating a response to greater nutrient availability rather than to greater space or less impedance to root growth. 4. Root proliferation inside decaying roots may improve recovery of nutrients released from decomposing tissues before they can be leached or immobilized in this intertidal environment. Greatest root proliferation in channels occurred in interior forest zones characterized by greater soil waterlogging, which suggests that this may be a strategy for nutrient capture that minimizes oxygen losses from the whole root system. 5. Improved efficiency of nutrient acquisition at the individual plant level has implications for nutrient economy at the ecosystem level and may explain, in part, how mangroves persist and grow in nutrient-poor environments.

  4. EFFECTS OF OZONE ON ROOT PROCESSES

    EPA Science Inventory

    Ozone alters root growth and root processes by first reducing photosynthesis and altering foliar metabolic pathways. The alteration in foliar metabolism is reflected in lowered carbohydrate levels in the roots. This can reduce key metabolic processes such as mineral uptake and sy...

  5. Cultivar selection for sugarbeet root rot resistance.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungal and bacterial root rots in sugar beet caused by Rhizoctonia solani (Rs) and Leuconostoc mesenteroides subsp. dextranicum (Lm) can lead to root yield losses greater than 50%. To reduce the impact of these root rots on sucrose loss in the field, storage, and factories, studies were conducted t...

  6. Effect of scapling on root respiration rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scalping improves root quality at harvest since impurities such as potassium, sodium, amino nitrogen and invert sugars that hinder sugarbeet processing are concentrated in the upper root crown. The effect of scalping on root storage properties, however, is less clear. A small study was conducted t...

  7. [Root caries--scanning electron microscopic observations].

    PubMed

    Heinrich, R; Hornová, J; Kneist, S; Künzel, W

    1990-01-01

    Sound and carious root surfaces of 24 extracted human teeth with extensive periodontal attachment loss were examined by SEM. The microflora covering the radicular surfaces was a complex flora consisting of filamentous and fusiform bacteria, short and long rods. Cocci and coccoid bacteria were observed on root surfaces. Bacterial invasion in the exposed peripheral root dentin was delayed by sclerotic dentin. PMID:2150459

  8. Springback in Root Gravitropism 1

    PubMed Central

    Leopold, A. Carl; Wettlaufer, Scott H.

    1989-01-01

    Conditions under which a gravistimulus of Merit corn roots (Zea mays L.) is withdrawn result in a subsequent loss of gravitropic curvature, an effect which we refer to as `springback.' This loss of curvature begins within 1 to 10 minutes after removal of the gravistimulus. It occurs regardless of the presence or absence of the root cap. It is insensitive to inhibitors of auxin transport (2,3,5-triiodobenzoic acid, naphthylphthalmaic acid) or to added auxin (2,4-dichlorophenoxyacetic acid). Springback is prevented if a clinostat treatment is interjected to neutralize gravistimulation during germination, which suggests that the change in curvature is a response to a `memory' effect carried over from a prior gravistimulation. PMID:11537456

  9. The rhizosphere revisited: root microbiomics

    PubMed Central

    Bakker, Peter A. H. M.; Berendsen, Roeland L.; Doornbos, Rogier F.; Wintermans, Paul C. A.; Pieterse, Corné M. J.

    2013-01-01

    The rhizosphere was defined over 100 years ago as the zone around the root where microorganisms and processes important for plant growth and health are located. Recent studies show that the diversity of microorganisms associated with the root system is enormous. This rhizosphere microbiome extends the functional repertoire of the plant beyond imagination. The rhizosphere microbiome of Arabidopsis thaliana is currently being studied for the obvious reason that it allows the use of the extensive toolbox that comes with this model plant. Deciphering plant traits that drive selection and activities of the microbiome is now a major challenge in which Arabidopsis will undoubtedly be a major research object. Here we review recent microbiome studies and discuss future research directions and applicability of the generated knowledge. PMID:23755059

  10. Phene Synergism between Root Hair Length and Basal Root Growth Angle for Phosphorus Acquisition1[OPEN

    PubMed Central

    Miguel, Magalhaes Amade

    2015-01-01

    Shallow basal root growth angle (BRGA) increases phosphorus acquisition efficiency by enhancing topsoil foraging because in most soils, phosphorus is concentrated in the topsoil. Root hair length and density (RHL/D) increase phosphorus acquisition by expanding the soil volume subject to phosphorus depletion through diffusion. We hypothesized that shallow BRGA and large RHL/D are synergetic for phosphorus acquisition, meaning that their combined effect is greater than the sum of their individual effects. To evaluate this hypothesis, phosphorus acquisition in the field in Mozambique was compared among recombinant inbred lines of common bean (Phaseolus vulgaris) having four distinct root phenotypes: long root hairs and shallow basal roots, long root hairs and deep basal roots, short root hairs and shallow basal roots, and short root hairs and deep basal roots. The results revealed substantial synergism between BRGA and RHL/D. Compared with short-haired, deep-rooted phenotypes, long root hairs increased shoot biomass under phosphorus stress by 89%, while shallow roots increased shoot biomass by 58%. Genotypes with both long root hairs and shallow roots had 298% greater biomass accumulation than short-haired, deep-rooted phenotypes. Therefore, the utility of shallow basal roots and long root hairs for phosphorus acquisition in combination is twice as large as their additive effects. We conclude that the anatomical phene of long, dense root hairs and the architectural phene of shallower basal root growth are synergetic for phosphorus acquisition. Phene synergism may be common in plant biology and can have substantial importance for plant fitness, as shown here. PMID:25699587

  11. Modeling root reinforcement using a root-failure Weibull survival function

    NASA Astrophysics Data System (ADS)

    Schwarz, M.; Giadrossich, F.; Cohen, D.

    2013-11-01

    Root networks contribute to slope stability through complex interactions with soil that include mechanical compression and tension. Due to the spatial heterogeneity of root distribution and the dynamics of root turnover, the quantification of root reinforcement on steep slopes is challenging and consequently the calculation of slope stability also. Although considerable progress has been made, some important aspects of root mechanics remain neglected. In this study we address specifically the role of root-strength variability on the mechanical behavior of a root bundle. Many factors contribute to the variability of root mechanical properties even within a single class of diameter. This work presents a new approach for quantifying root reinforcement that considers the variability of mechanical properties of each root diameter class. Using the data of laboratory tensile tests and field pullout tests, we calibrate the parameters of the Weibull survival function to implement the variability of root strength in a numerical model for the calculation of root reinforcement (RBMw). The results show that, for both laboratory and field data sets, the parameters of the Weibull distribution may be considered constant with the exponent equal to 2 and the normalized failure displacement equal to 1. Moreover, the results show that the variability of root strength in each root diameter class has a major influence on the behavior of a root bundle with important implications when considering different approaches in slope stability calculation. Sensitivity analysis shows that the calibration of the equations of the tensile force, the elasticity of the roots, and the root distribution are the most important steps. The new model allows the characterization of root reinforcement in terms of maximum pullout force, stiffness, and energy. Moreover, it simplifies the implementation of root reinforcement in slope stability models. The realistic quantification of root reinforcement for tensile

  12. Root-cubing and general root-powering methods for finding the zeros of polynomials

    NASA Technical Reports Server (NTRS)

    Bareiss, E. H.

    1969-01-01

    Mathematical analysis technique generalizes a root squaring and root cubing method into a general root powering method. The introduction of partitioned polynomials into this general root powering method simplifies the coding of the polynomial transformations into input data suitable for processing by computer. The method includes analytic functions.

  13. Application of glutathione to roots selectively inhibits cadmium transport from roots to shoots in oilseed rape

    PubMed Central

    Nakamura, Shin-ichi

    2013-01-01

    Glutathione is a tripeptide involved in various aspects of plant metabolism. This study investigated the effects of the reduced form of glutathione (GSH) applied to specific organs (source leaves, sink leaves, and roots) on cadmium (Cd) distribution and behaviour in the roots of oilseed rape plants (Brassica napus) cultured hydroponically. The translocation ratio of Cd from roots to shoots was significantly lower in plants that had root treatment of GSH than in control plants. GSH applied to roots reduced the Cd concentration in the symplast sap of root cells and inhibited root-to-shoot Cd translocation via xylem vessels significantly. GSH applied to roots also activated Cd efflux from root cells to the hydroponic solution. Inhibition of root-to-shoot translocation of Cd was visualized, and the activation of Cd efflux from root cells was also shown by using a positron-emitting tracer imaging system (PETIS). This study investigated a similar inhibitory effect on root-to-shoot translocation of Cd by the oxidized form of glutathione, GSSG. Inhibition of Cd accumulation by GSH was abolished by a low-temperature treatment. Root cells of plants exposed to GSH in the root zone had less Cd available for xylem loading by actively excluding Cd from the roots. Consequently, root-to-shoot translocation of Cd was suppressed and Cd accumulation in the shoot decreased. PMID:23364937

  14. Estimate of fine root production including the impact of decomposed roots in a Bornean tropical rainforest

    NASA Astrophysics Data System (ADS)

    Katayama, Ayumi; Khoon Koh, Lip; Kume, Tomonori; Makita, Naoki; Matsumoto, Kazuho; Ohashi, Mizue

    2016-04-01

    Considerable carbon is allocated belowground and used for respiration and production of roots. It is reported that approximately 40 % of GPP is allocated belowground in a Bornean tropical rainforest, which is much higher than those in Neotropical rainforests. This may be caused by high root production in this forest. Ingrowth core is a popular method for estimating fine root production, but recent study by Osawa et al. (2012) showed potential underestimates of this method because of the lack of consideration of the impact of decomposed roots. It is important to estimate fine root production with consideration for the decomposed roots, especially in tropics where decomposition rate is higher than other regions. Therefore, objective of this study is to estimate fine root production with consideration of decomposed roots using ingrowth cores and root litter-bag in the tropical rainforest. The study was conducted in Lambir Hills National Park in Borneo. Ingrowth cores and litter bags for fine roots were buried in March 2013. Eighteen ingrowth cores and 27 litter bags were collected in May, September 2013, March 2014 and March 2015, respectively. Fine root production was comparable to aboveground biomass increment and litterfall amount, and accounted only 10% of GPP in this study site, suggesting most of the carbon allocated to belowground might be used for other purposes. Fine root production was comparable to those in Neotropics. Decomposed roots accounted for 18% of fine root production. This result suggests that no consideration of decomposed fine roots may cause underestimate of fine root production.

  15. Effects of substrate disturbance on secondary plant succession; Mojave Desert, California.

    USGS Publications Warehouse

    Prose, D.V.; Metzger, S.K.; Wilshire, H.G.

    1987-01-01

    Soil compaction, removal of the top layer of soil, and alteration of drainage channel density caused significant changes in perennial plant cover, density, and relative species composition. Long-lived species, predominantly Larrea tridentata, were dominant in all control areas but percentage cover and density were greatly reduced in areas where substrate alterations were significant. Pioneer species such as Ambrosia dumosa and Hymenoclea salsola had percentage cover values similar to or greater than controls in most areas where substrate alterations were significant, and these species were dominant in the majority of disturbed areas. -from Authors

  16. The pattern of secondary root formation in curving roots of Arabidopsis thaliana (L.) Heynh

    NASA Technical Reports Server (NTRS)

    Fortin, M. C.; Pierce, F. J.; Poff, K. L.

    1989-01-01

    A gravitational stimulus was used to induce the curvature of the main root of Arabidopsis thaliana. The number of secondary roots increased on the convex side and decreased on the concave side of any curved main root axes in comparison with straight roots used as the control. The same phenomenon was observed with the curved main roots of plants grown on a clinostat and of mutant plants exhibiting random root orientation. The data suggest that the pattern of lateral root formation is associated with curvature but is independent of the environmental stimuli used to induce curvature.

  17. Optimal root arrangement of cereal crops

    NASA Astrophysics Data System (ADS)

    Jung, Yeonsu; Park, Keunhwan; Kim, Ho-Young

    2015-11-01

    The plant root absorbs water from the soil and supplies it to the rest part of the plant. It consists of a number of root fibers, through whose surfaces water uptake occurs. There is an intriguing observation that for most of cereal crops such as maize and wheat, the volume density of root in the soil declines exponentially as a function of depth. To understand this empirical finding, we construct a theoretical model of root water uptake, where mass transfer into root surface is modeled just as heat flux around a fin. Agreement between the theoretically predicted optimal root distribution in vertical direction and biological data supports the hypothesis that the plant root has evolved to achieve the optimal water uptake in competition with neighbors. This study has practical implication in the agricultural industry as well as optimal design of water transport networks in both micro- and macroscales. Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.

  18. General complex polynomial root solver

    NASA Astrophysics Data System (ADS)

    Skowron, J.; Gould, A.

    2012-12-01

    This general complex polynomial root solver, implemented in Fortran and further optimized for binary microlenses, uses a new algorithm to solve polynomial equations and is 1.6-3 times faster than the ZROOTS subroutine that is commercially available from Numerical Recipes, depending on application. The largest improvement, when compared to naive solvers, comes from a fail-safe procedure that permits skipping the majority of the calculations in the great majority of cases, without risking catastrophic failure in the few cases that these are actually required.

  19. Xanthones from Garcinia propinqua Roots.

    PubMed

    Meesakul, Pornphimol; Pansanit, Acharavadee; Maneerat, Wisanu; Sripisut, Tawanun; Ritthiwigrom, Thunwadee; Machana, Theeraphan; Cheenpracha, Sarot; Laphookhieo, Surat

    2016-01-01

    Phytochemical investigation of Garcinia propinqua roots led to the isolation and identification of a new xanthone, doitunggarcinone D (1), together with 15 known compounds (2-16). Their structures were elucidated by intensive analysis of spectroscopic data. Compounds 3, 6, 7, 14, 15 and 16 exhibited strong antibacterial activity against Bacillus subtilis TISTR 088 with MIC values in the range of 1-4 µg/mL. Compounds 3, 7, 10 and 14 also showed good antibacterial activity against B. cereus TISTR 688 with MIC values ranging from 4-8 µg/mL. PMID:26996028

  20. Morphometric data of canine sacral nerve roots with reference to electrical sacral root stimulation.

    PubMed

    Rijkhoff, N J; Koldewijn, E L; d'Hollosy, W; Debruyne, F M; Wijkstra, H

    1996-01-01

    Experiments to investigate restoration of lower urinary tract control by electrical stimulation of the sacral nerve roots are mostly performed on dogs, yet little morphometric data (such as canine root and fiber diameter distributions) are available. The aim of this study was to acquire morphometric data of the intradural canine sacral dorsal and ventral roots (S1-S3). Cross-sections of sacral roots of two beagle dogs were analyzed using a light microscope and image processing software. The cross-sectional area of each root was measured. The diameters of the fibers and the axons in the cross-sections of the S2 and S3 roots were measured and used to construct nerve fiber diameter frequency distribution histograms. The results show a unimodal diameter distribution for the dorsal roots and a bimodal distribution for the ventral roots. In addition the average ratio g of the axon diameter to fiber diameter was calculated for each root. PMID:8732990

  1. Root canal treatment of a maxillary first premolar with three roots

    PubMed Central

    Mathew, Josey; Devadathan, Aravindan; Syriac, Gibi; Shamini, Sai

    2015-01-01

    Successful root canal treatment needs a thorough knowledge of both internal and external anatomy of a tooth. Variations in root canal anatomy constitute an impressive challenge to the successful completion of endodontic treatment. Undetected extra roots and canals are a major reason for failed root canal treatment. Three separate roots in a maxillary first premolar have a very low incidence of 0.5–6%. Three rooted premolars are anatomically similar to molars and are sometimes called “small molars or radiculous molars.” This article explains the diagnosis and endodontic management of a three rooted maxillary premolar with separate canals in each root highlighting that statistics may indicate a low incidence of abnormal variations in root canal morphology of a tooth, but aberrant anatomy is a possibility in any tooth. Hence, modern diagnostics like cone beam computed tomography, and endodontic operating microscope may have to be used more for predictable endodontic treatment. PMID:26538958

  2. Inhibition of auxin movement from the shoot into the root inhibits lateral root development in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Reed, R. C.; Brady, S. R.; Muday, G. K.

    1998-01-01

    In roots two distinct polar movements of auxin have been reported that may control different developmental and growth events. To test the hypothesis that auxin derived from the shoot and transported toward the root controls lateral root development, the two polarities of auxin transport were uncoupled in Arabidopsis. Local application of the auxin-transport inhibitor naphthylphthalamic acid (NPA) at the root-shoot junction decreased the number and density of lateral roots and reduced the free indoleacetic acid (IAA) levels in the root and [3H]IAA transport into the root. Application of NPA to the basal half of or at several positions along the root only reduced lateral root density in regions that were in contact with NPA or in regions apical to the site of application. Lateral root development was restored by application of IAA apical to NPA application. Lateral root development in Arabidopsis roots was also inhibited by excision of the shoot or dark growth and this inhibition was reversible by IAA. Together, these results are consistent with auxin transport from the shoot into the root controlling lateral root development.

  3. Foraging strategies in trees of different root morphology: the role of root lifespan.

    PubMed

    Adams, Thomas S; McCormack, M Luke; Eissenstat, David M

    2013-09-01

    Resource exploitation of patches is influenced not simply by the rate of root production in the patches but also by the lifespan of the roots inhabiting the patches. We examined the effect of sustained localized nitrogen (N) fertilization on root lifespan in four tree species that varied widely in root morphology and presumed foraging strategy. The study was conducted in a 12-year-old common garden in central Pennsylvania using a combination of data from minirhizotron and root in-growth cores. The two fine-root tree species, Acer negundo L. and Populus tremuloides Michx., exhibited significant increases in root lifespan with local N fertilization; no significant responses were observed in the two coarse-root tree species, Sassafras albidum Nutt. and Liriodendron tulipifera L. Across species, coarse-root tree species had longer median root lifespan than fine-root tree species. Localized N fertilization did not significantly increase the N concentration or the respiration of the roots growing in the N-rich patch. Our results suggest that some plant species appear to regulate the lifespan of different portions of their root system to improve resource acquisition while other species do not. Our results are discussed in the context of different strategies of foraging of nutrient patches in species of different root morphology. PMID:24128849

  4. PATTERNS IN SOIL FERTILITY AND ROOT HERBIVORY INTERACT TO INFLUENCE FINE-ROOT DYNAMICS.

    SciTech Connect

    Stevens, Glen, N.; Jones, Robert, H.

    2006-03-01

    Fine-scale soil nutrient enrichment typically stimulates root growth, but it may also increase root herbivory, resulting in trade-offs for plant species and potentially influencing carbon cycling patterns. We used root ingrowth cores to investigate the effects of microsite fertility and root herbivory on root biomass in an aggrading upland forest in the coastal plain of South Carolina, USA. Treatments were randomly assigned to cores from a factorial combination of fertilizer and insecticide. Soil, soil fauna, and roots were removed from the cores at the end of the experiment (8–9 mo), and roots were separated at harvest into three diameter classes. Each diameter class responded differently to fertilizer and insecticide treatments. The finest roots (,1.0 mm diameter), which comprised well over half of all root biomass, were the only ones to respond significantly to both treatments, increasing when fertilizer and when insecticide were added (each P , 0.0001), with maximum biomass found where the treatments were combined (interaction term significant, P , 0.001). These results suggest that root-feeding insects have a strong influence on root standing crop with stronger herbivore impacts on finer roots and within more fertile microsites. Thus, increased vulnerability to root herbivory is a potentially significant cost of root foraging in nutrient-rich patches.

  5. A statistical approach to root system classification

    PubMed Central

    Bodner, Gernot; Leitner, Daniel; Nakhforoosh, Alireza; Sobotik, Monika; Moder, Karl; Kaul, Hans-Peter

    2013-01-01

    Plant root systems have a key role in ecology and agronomy. In spite of fast increase in root studies, still there is no classification that allows distinguishing among distinctive characteristics within the diversity of rooting strategies. Our hypothesis is that a multivariate approach for “plant functional type” identification in ecology can be applied to the classification of root systems. The classification method presented is based on a data-defined statistical procedure without a priori decision on the classifiers. The study demonstrates that principal component based rooting types provide efficient and meaningful multi-trait classifiers. The classification method is exemplified with simulated root architectures and morphological field data. Simulated root architectures showed that morphological attributes with spatial distribution parameters capture most distinctive features within root system diversity. While developmental type (tap vs. shoot-borne systems) is a strong, but coarse classifier, topological traits provide the most detailed differentiation among distinctive groups. Adequacy of commonly available morphologic traits for classification is supported by field data. Rooting types emerging from measured data, mainly distinguished by diameter/weight and density dominated types. Similarity of root systems within distinctive groups was the joint result of phylogenetic relation and environmental as well as human selection pressure. We concluded that the data-define classification is appropriate for integration of knowledge obtained with different root measurement methods and at various scales. Currently root morphology is the most promising basis for classification due to widely used common measurement protocols. To capture details of root diversity efforts in architectural measurement techniques are essential. PMID:23914200

  6. A statistical approach to root system classification.

    PubMed

    Bodner, Gernot; Leitner, Daniel; Nakhforoosh, Alireza; Sobotik, Monika; Moder, Karl; Kaul, Hans-Peter

    2013-01-01

    Plant root systems have a key role in ecology and agronomy. In spite of fast increase in root studies, still there is no classification that allows distinguishing among distinctive characteristics within the diversity of rooting strategies. Our hypothesis is that a multivariate approach for "plant functional type" identification in ecology can be applied to the classification of root systems. The classification method presented is based on a data-defined statistical procedure without a priori decision on the classifiers. The study demonstrates that principal component based rooting types provide efficient and meaningful multi-trait classifiers. The classification method is exemplified with simulated root architectures and morphological field data. Simulated root architectures showed that morphological attributes with spatial distribution parameters capture most distinctive features within root system diversity. While developmental type (tap vs. shoot-borne systems) is a strong, but coarse classifier, topological traits provide the most detailed differentiation among distinctive groups. Adequacy of commonly available morphologic traits for classification is supported by field data. Rooting types emerging from measured data, mainly distinguished by diameter/weight and density dominated types. Similarity of root systems within distinctive groups was the joint result of phylogenetic relation and environmental as well as human selection pressure. We concluded that the data-define classification is appropriate for integration of knowledge obtained with different root measurement methods and at various scales. Currently root morphology is the most promising basis for classification due to widely used common measurement protocols. To capture details of root diversity efforts in architectural measurement techniques are essential. PMID:23914200

  7. Root hairs aid soil penetration by anchoring the root surface to pore walls

    PubMed Central

    Bengough, A. Glyn; Loades, Kenneth; McKenzie, Blair M.

    2016-01-01

    The physical role of root hairs in anchoring the root tip during soil penetration was examined. Experiments using a hairless maize mutant (Zea mays: rth3–3) and its wild-type counterpart measured the anchorage force between the primary root of maize and the soil to determine whether root hairs enabled seedling roots in artificial biopores to penetrate sandy loam soil (dry bulk density 1.0–1.5g cm−3). Time-lapse imaging was used to analyse root and seedling displacements in soil adjacent to a transparent Perspex interface. Peak anchorage forces were up to five times greater (2.5N cf. 0.5N) for wild-type roots than for hairless mutants in 1.2g cm−3 soil. Root hair anchorage enabled better soil penetration for 1.0 or 1.2g cm−3 soil, but there was no significant advantage of root hairs in the densest soil (1.5g cm−3). The anchorage force was insufficient to allow root penetration of the denser soil, probably because of less root hair penetration into pore walls and, consequently, poorer adhesion between the root hairs and the pore walls. Hairless seedlings took 33h to anchor themselves compared with 16h for wild-type roots in 1.2g cm−3 soil. Caryopses were often pushed several millimetres out of the soil before the roots became anchored and hairless roots often never became anchored securely.The physical role of root hairs in anchoring the root tip may be important in loose seed beds above more compact soil layers and may also assist root tips to emerge from biopores and penetrate the bulk soil. PMID:26798027

  8. Root hairs aid soil penetration by anchoring the root surface to pore walls.

    PubMed

    Bengough, A Glyn; Loades, Kenneth; McKenzie, Blair M

    2016-02-01

    The physical role of root hairs in anchoring the root tip during soil penetration was examined. Experiments using a hairless maize mutant (Zea mays: rth3-3) and its wild-type counterpart measured the anchorage force between the primary root of maize and the soil to determine whether root hairs enabled seedling roots in artificial biopores to penetrate sandy loam soil (dry bulk density 1.0-1.5g cm(-3)). Time-lapse imaging was used to analyse root and seedling displacements in soil adjacent to a transparent Perspex interface. Peak anchorage forces were up to five times greater (2.5N cf. 0.5N) for wild-type roots than for hairless mutants in 1.2g cm(-3) soil. Root hair anchorage enabled better soil penetration for 1.0 or 1.2g cm(-3) soil, but there was no significant advantage of root hairs in the densest soil (1.5g cm(-3)). The anchorage force was insufficient to allow root penetration of the denser soil, probably because of less root hair penetration into pore walls and, consequently, poorer adhesion between the root hairs and the pore walls. Hairless seedlings took 33h to anchor themselves compared with 16h for wild-type roots in 1.2g cm(-3) soil. Caryopses were often pushed several millimetres out of the soil before the roots became anchored and hairless roots often never became anchored securely.The physical role of root hairs in anchoring the root tip may be important in loose seed beds above more compact soil layers and may also assist root tips to emerge from biopores and penetrate the bulk soil. PMID:26798027

  9. 1-aminocyclopropane-1-carboxylic acid (ACC) concentration and ACC synthase expression in soybean roots and root tips and soybean cyst nematode (Heterodera glycines) colonized root pieces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It's fairly well established that a functional ethylene response path is important to root knot and cyst nematode colonization of plant roots. However, ethylene plays many roles in root development and the role of ethylene in nematode colonization of roots may be indirect, e.g. lateral root initiati...

  10. Roots at the percolation threshold

    NASA Astrophysics Data System (ADS)

    Kroener, Eva; Ahmed, Mutez Ali; Carminati, Andrea

    2015-04-01

    The rhizosphere is the layer of soil around the roots where complex and dynamic interactions between plants and soil affect the capacity of plants to take up water. The physical properties of the rhizosphere are affected by mucilage, a gel exuded by roots. Mucilage can absorb large volumes of water, but it becomes hydrophobic after drying. We use a percolation model to describe the rewetting of dry rhizosphere. We find that at a critical mucilage concentration the rhizosphere becomes impermeable. The critical mucilage concentration depends on the radius of the soil particle size. Capillary rise experiments with neutron radiography prove that for concentrations below the critical mucilage concentration water could easily cross the rhizosphere, while above the critical concentration water could no longer percolate through it. Our studies, together with former observations of water dynamics in the rhizosphere, suggest that the rhizosphere is near the percolation threshold, where small variations in mucilage concentration sensitively alter the soil hydraulic conductivity. Is mucilage exudation a plant mechanism to efficiently control the rhizosphere conductivity and the access to water?

  11. Roots at the percolation threshold.

    PubMed

    Kroener, Eva; Ahmed, Mutez Ali; Carminati, Andrea

    2015-04-01

    The rhizosphere is the layer of soil around the roots where complex and dynamic interactions between plants and soil affect the capacity of plants to take up water. The physical properties of the rhizosphere are affected by mucilage, a gel exuded by roots. Mucilage can absorb large volumes of water, but it becomes hydrophobic after drying. We use a percolation model to describe the rewetting of dry rhizosphere. We find that at a critical mucilage concentration the rhizosphere becomes impermeable. The critical mucilage concentration depends on the radius of the soil particle size. Capillary rise experiments with neutron radiography prove that for concentrations below the critical mucilage concentration water could easily cross the rhizosphere, while above the critical concentration water could no longer percolate through it. Our studies, together with former observations of water dynamics in the rhizosphere, suggest that the rhizosphere is near the percolation threshold, where small variations in mucilage concentration sensitively alter the soil hydraulic conductivity. Is mucilage exudation a plant mechanism to efficiently control the rhizosphere conductivity and the access to water? PMID:25974526

  12. Salt stress signals shape the plant root.

    PubMed

    Galvan-Ampudia, Carlos S; Testerink, Christa

    2011-06-01

    Plants use different strategies to deal with high soil salinity. One strategy is activation of pathways that allow the plant to export or compartmentalise salt. Relying on their phenotypic plasticity, plants can also adjust their root system architecture (RSA) and the direction of root growth to avoid locally high salt concentrations. Here, we highlight RSA responses to salt and osmotic stress and the underlying mechanisms. A model is presented that describes how salinity affects auxin distribution in the root. Possible intracellular signalling pathways linking salinity to root development and direction of root growth are discussed. These involve perception of high cytosolic Na+ concentrations in the root, activation of lipid signalling and protein kinase activity and modulation of endocytic pathways. PMID:21511515

  13. High resolution modeling of water and nutrient uptake by plant roots: at a scale from single root to root system

    NASA Astrophysics Data System (ADS)

    Abesha, Betiglu; Vanderborght, Jan; Javaux, Mathieu; Schnepf, Andrea; Vereecken, Harry

    2014-05-01

    The uptake of nutrients by plant roots is a multiscale problem. At the small scale, nutrient fluxes towards single roots lead to strong gradients in nutrient concentrations around single roots. At the scale of the root system and soil profile, nutrient fluxes are generated by water fluxes and variations in nutrient uptake due to spatially varying root density, nutrient concentrations and water contents. In this contribution, we present a numerical simulation model that describes the processes at the scale of a single root and the scale of the entire root system simultaneously. Water flow and nutrient transport in the soil are described by the 3-D Richards and advection-dispersion equations, respectively. Water uptake by a root segment is simulated based on the difference between the soil water potential at the soil root interface and in the xylem tissue. The xylem water potential is derived from solving a set of flow equations that describe flow in the root network (Javaux et al., 2008). Nutrient uptake by a segment is simulated as a function of the nutrient concentration at the soil-root interface using a nonlinear Michaelis-Menten equation. An accurate description of the nutrient concentrations gradients around single roots requires a spatial resolution in the sub mm scale and is therefore not feasible for simulations of the entire root system or soil profile. In order to address this problem, a 1-D axisymmetric model (Barber and Cushman, 1981) was used to describe nutrient transport towards a single root segment. The network of connected cylindrical models was coupled to a 3-D regular grid that was used to solve the flow and transport equations at the root system scale. The coupling was done by matching the fluxes across the interfaces of the voxels of the 3-D grid that contain root segments with the fluxes at the outer boundaries of the cylindrical domains and by matching the sink terms in these voxels with uptake by the root segments. To demonstrate the

  14. Root phenology in a changing climate.

    PubMed

    Radville, Laura; McCormack, M Luke; Post, Eric; Eissenstat, David M

    2016-06-01

    Plant phenology is one of the strongest indicators of ecological responses to climate change, and altered phenology can have pronounced effects on net primary production, species composition in local communities, greenhouse gas fluxes, and ecosystem processes. Although many studies have shown that aboveground plant phenology advances with warmer temperatures, demonstration of a comparable association for belowground phenology has been lacking because the factors that influence root phenology are poorly understood. Because roots can constitute a large fraction of plant biomass, and root phenology may not respond to warming in the same way as shoots, this represents an important knowledge gap in our understanding of how climate change will influence phenology and plant performance. We review studies of root phenology and provide suggestions to direct future research. Only 29% of examined studies approached root phenology quantitatively, strongly limiting interpretation of results across studies. Therefore, we suggest that researchers emphasize quantitative analyses in future phenological studies. We suggest that root initiation, peak growth, and root cessation may be under different controls. Root initiation and cessation may be more constrained by soil temperature and the timing of carbon availability, whereas the timing of peak root growth may represent trade-offs among competing plant sinks. Roots probably do not experience winter dormancy in the same way as shoots: 89% of the studies that examined winter phenology found evidence of growth during winter months. More research is needed to observe root phenology, and future studies should be careful to capture winter and early season phenology. This should be done quantitatively, with direct observations of root growth utilizing rhizotrons or minirhizotrons. PMID:26931171

  15. Root Doctors as Providers of Primary Care

    PubMed Central

    Stitt, Van J.

    1983-01-01

    Physicians in primary care recognize that as many as 65 percent of the patients seen in their offices are there for psychological reasons. In any southern town with a moderate population of blacks, there are at least two “root doctors.” These root doctors have mastered the power of autosuggestion and are treating these patients with various forms of medication and psychological counseling. This paper updates the practicing physician on root doctors who practice primary care. PMID:6887277

  16. Root doctors as providers of primary care.

    PubMed

    Stitt, V J

    1983-07-01

    Physicians in primary care recognize that as many as 65 percent of the patients seen in their offices are there for psychological reasons. In any southern town with a moderate population of blacks, there are at least two "root doctors." These root doctors have mastered the power of autosuggestion and are treating these patients with various forms of medication and psychological counseling. This paper updates the practicing physician on root doctors who practice primary care. PMID:6887277

  17. Temperature sensing by primary roots of maize

    NASA Technical Reports Server (NTRS)

    Poff, K. L.

    1990-01-01

    Zea mays L. seedlings, grown on agar plates at 26 degrees C, reoriented the original vertical direction of their primary root when exposed to a thermal gradient applied perpendicular to the gravity vector. The magnitude and direction of curvature can not be explained simply by either a temperature or a humidity effect on root elongation. It is concluded that primary roots of maize sense temperature gradients in addition to sensing the gravitational force.

  18. Advanced Techniques for Root Cause Analysis

    Energy Science and Technology Software Center (ESTSC)

    2000-09-19

    Five items make up this package, or can be used individually. The Chronological Safety Management Template utilizes a linear adaptation of the Integrated Safety Management System laid out in the form of a template that greatly enhances the ability of the analyst to perform the first step of any investigation which is to gather all pertinent facts and identify causal factors. The Problem Analysis Tree is a simple three (3) level problem analysis tree whichmore » is easier for organizations outside of WSRC to use. Another part is the Systemic Root Cause Tree. One of the most basic and unique features of Expanded Root Cause Analysis is the Systemic Root Cause portion of the Expanded Root Cause Pyramid. The Systemic Root Causes are even more basic than the Programmatic Root Causes and represent Root Causes that cut across multiple (if not all) programs in an organization. the Systemic Root Cause portion contains 51 causes embedded at the bottom level of a three level Systemic Root Cause Tree that is divided into logical, organizationally based categorie to assist the analyst. The Computer Aided Root Cause Analysis that allows the analyst at each level of the Pyramid to a) obtain a brief description of the cause that is being considered, b) record a decision that the item is applicable, c) proceed to the next level of the Pyramid to see only those items at the next level of the tree that are relevant to the particular cause that has been chosen, and d) at the end of the process automatically print out a summary report of the incident, the causal factors as they relate to the safety management system, the probable causes, apparent causes, Programmatic Root Causes and Systemic Root Causes for each causal factor and the associated corrective action.« less

  19. Springback and diagravitropism in Merit corn roots.

    PubMed Central

    Kelly, M O; Leopold, A C

    1992-01-01

    Dark-treated Merit corn (Zea mays L.) roots are diagravitropic and lose curvature upon withdrawal of the gravity stimulus (springback). Springback was not detected in a variety of corn that is orthogravitropic in the dark, nor in Merit roots in which tropistic response was enhanced either with red light or with abscisic acid. A possible interpretation is that springback may be associated with a weak growth response of diagravitropic roots. PMID:11537884

  20. Springback and diagravitropism in Merit corn roots

    NASA Technical Reports Server (NTRS)

    Kelly, M. O.; Leopold, A. C.

    1992-01-01

    Dark-treated Merit corn (Zea mays L.) roots are diagravitropic and lose curvature upon withdrawal of the gravity stimulus (springback). Springback was not detected in a variety of corn that is orthogravitropic in the dark, nor in Merit roots in which tropistic response was enhanced either with red light or with abscisic acid. A possible interpretation is that springback may be associated with a weak growth response of diagravitropic roots.

  1. Springback and diagravitropism in Merit corn roots.

    PubMed

    Kelly, M O; Leopold, A C

    1992-06-01

    Dark-treated Merit corn (Zea mays L.) roots are diagravitropic and lose curvature upon withdrawal of the gravity stimulus (springback). Springback was not detected in a variety of corn that is orthogravitropic in the dark, nor in Merit roots in which tropistic response was enhanced either with red light or with abscisic acid. A possible interpretation is that springback may be associated with a weak growth response of diagravitropic roots. PMID:11537884

  2. Temperature sensing by primary roots of maize

    SciTech Connect

    Fortin, M.C.A.; Poff, K.L. )

    1990-09-01

    Zea mays L. seedlings, grown on agar plates at 26{degree}C, reoriented the original vertical direction of their primary root when exposed to a thermal gradient applied perpendicular to the gravity vector. The magnitude and direction of curvature can not be explained simply by either a temperature or a humidity effect on root elongation. It is concluded that primary roots of maize sense temperature gradients in addition to sensing the gravitational force.

  3. Behavioral response of grape root borer (Lepidoptera: Sesiidae) neonates to grape root volatiles.

    PubMed

    Rijal, J P; Zhang, A; Bergh, J C

    2013-12-01

    Grape root borer, Vitacea polistiformis (Harris), is an oligophagous and potentially destructive pest of grape in commercial vineyards throughout much of the eastern United States. Larvae feed on vine roots, although little is known about their below-ground interactions with host plants. The behavioral response of groups of grape root borer neonates to stimuli from host and nonhost roots was evaluated in single and paired stimuli bioassays in which stimuli were presented in opposing wells attached to the bottom of petri dish arenas. Stimulus sources included root pieces and root headspace volatiles from 3309 and 420-A grape rootstocks (host) and apple (nonhost) and ethanol-based extracts of 3309 and 420-A roots. In single stimulus assays, significantly more larvae were recovered from wells containing grape roots, apple roots, grape extracts, and grape root volatiles than from control wells, but there was no significant response to volatiles collected from the headspace of apple roots. In paired stimuli assays, significantly more larvae were recovered from wells containing grape than apple roots. There was no difference in larval distribution between wells when 420-A and 3309 roots were presented simultaneously, although a significantly greater response to 3309 than 420-A root extract was recorded. When soil was added to the assays, significantly more larvae were recovered from wells containing grape roots than from those containing only soil, but this response was not detected in assays using buried apple roots. These results are discussed in relation to the plant-insect interactions between grape root borer larvae and their Vitaceae hosts. PMID:24216488

  4. Characterization of Pearl Millet Root Architecture and Anatomy Reveals Three Types of Lateral Roots

    PubMed Central

    Passot, Sixtine; Gnacko, Fatoumata; Moukouanga, Daniel; Lucas, Mikaël; Guyomarc’h, Soazig; Ortega, Beatriz Moreno; Atkinson, Jonathan A.; Belko, Marème N.; Bennett, Malcolm J.; Gantet, Pascal; Wells, Darren M.; Guédon, Yann; Vigouroux, Yves; Verdeil, Jean-Luc; Muller, Bertrand; Laplaze, Laurent

    2016-01-01

    Pearl millet plays an important role for food security in arid regions of Africa and India. Nevertheless, it is considered an orphan crop as it lags far behind other cereals in terms of genetic improvement efforts. Breeding pearl millet varieties with improved root traits promises to deliver benefits in water and nutrient acquisition. Here, we characterize early pearl millet root system development using several different root phenotyping approaches that include rhizotrons and microCT. We report that early stage pearl millet root system development is characterized by a fast growing primary root that quickly colonizes deeper soil horizons. We also describe root anatomical studies that revealed three distinct types of lateral roots that form on both primary roots and crown roots. Finally, we detected significant variation for two root architectural traits, primary root lenght and lateral root density, in pearl millet inbred lines. This study provides the basis for subsequent genetic experiments to identify loci associated with interesting early root development traits in this important cereal. PMID:27379124

  5. Root-to-Root Travel of the Beneficial Bacterium Azospirillum brasilense†

    PubMed Central

    Bashan, Yoav; Holguin, Gina

    1994-01-01

    The root-to-root travel of the beneficial bacterium Azospirillum brasilense on wheat and soybean roots in agar, sand, and light-textured soil was monitored. We used a motile wild-type (Mot+) strain and a motility-deficient (Mot-) strain which was derived from the wild-type strain. The colonization levels of inoculated roots were similar for the two strains. Mot+ cells moved from inoculated roots (either natural or artificial roots in agar, sand, or light-textured soil) to noninoculated roots, where they formed a band-type colonization composed of bacterial aggregates encircling a limited part of the root, regardless of the plant species. The Mot- strain did not move toward noninoculated roots of either plant species and usually stayed at the inoculation site and root tips. The effect of attractants and repellents was the primary factor governing the motility of Mot+ cells in the presence of adequate water. We propose that interroot travel of A. brasilense is an essential preliminary step in the root-bacterium recognition mechanism. Bacterial motility might have a general role in getting Azospirillum cells to the site where firmer attachment favors colonization of the root system. Azospirillum travel toward plants is a nonspecific active process which is not directly dependent on nutrient deficiency but is a consequence of a nonspecific bacterial chemotaxis, influenced by the balance between attractants and possibly repellents leaked by the root. PMID:16349297

  6. Characterization of Pearl Millet Root Architecture and Anatomy Reveals Three Types of Lateral Roots.

    PubMed

    Passot, Sixtine; Gnacko, Fatoumata; Moukouanga, Daniel; Lucas, Mikaël; Guyomarc'h, Soazig; Ortega, Beatriz Moreno; Atkinson, Jonathan A; Belko, Marème N; Bennett, Malcolm J; Gantet, Pascal; Wells, Darren M; Guédon, Yann; Vigouroux, Yves; Verdeil, Jean-Luc; Muller, Bertrand; Laplaze, Laurent

    2016-01-01

    Pearl millet plays an important role for food security in arid regions of Africa and India. Nevertheless, it is considered an orphan crop as it lags far behind other cereals in terms of genetic improvement efforts. Breeding pearl millet varieties with improved root traits promises to deliver benefits in water and nutrient acquisition. Here, we characterize early pearl millet root system development using several different root phenotyping approaches that include rhizotrons and microCT. We report that early stage pearl millet root system development is characterized by a fast growing primary root that quickly colonizes deeper soil horizons. We also describe root anatomical studies that revealed three distinct types of lateral roots that form on both primary roots and crown roots. Finally, we detected significant variation for two root architectural traits, primary root lenght and lateral root density, in pearl millet inbred lines. This study provides the basis for subsequent genetic experiments to identify loci associated with interesting early root development traits in this important cereal. PMID:27379124

  7. Measurements of water uptake of maize roots: the key function of lateral roots

    NASA Astrophysics Data System (ADS)

    Ahmed, M. A.; Zarebanadkouki, M.; Kroener, E.; Kaestner, A.; Carminati, A.

    2014-12-01

    Maize (Zea mays L.) is one of the most important crop worldwide. Despite its importance, there is limited information on the function of different root segments and root types of maize in extracting water from soils. Therefore, the aim of this study was to investigate locations of root water uptake in maize. We used neutron radiography to: 1) image the spatial distribution of maize roots in soil and 2) trace the transport of injected deuterated water (D2O) in soil and roots. Maizes were grown in aluminum containers (40×38×1 cm) filled with a sandy soil. When the plants were 16 days old, we injected D2O into selected soil regions containing primary, seminal and lateral roots. The experiments were performed during the day (transpiring plants) and night (not transpiring plants). The transport of D2O into roots was simulated using a new convection-diffusion numerical model of D2O transport into roots. By fitting the observed D2O transport we quantified the diffusional permeability and the water uptake of the different root segments. The maize root architecture consisted of a primary root, 4-5 seminal roots and many lateral roots connected to the primary and seminal roots. Laterals emerged from the proximal 15 cm of the primary and seminal roots. Water uptake occurred primarily in lateral roots. Lateral roots had the highest diffusional permeability (9.4×10-7), which was around six times higher that the diffusional permeability of the old seminal segments (1.4×10-7), and two times higher than the diffusional permeability of the young seminal segments (4.7×10-7). The radial flow of D2O into the lateral (6.7×10-5 ) was much higher than in the young seminal roots (1.1×10-12). The radial flow of D2O into the old seminal was negligible. We concluded that the function of the primary and seminal roots was to collect water from the lateral roots and transport it to the shoot. A maize root system with lateral roots branching from deep primary and seminal roots would be

  8. Genetic ablation of root cap cells in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Tsugeki, R.; Fedoroff, N. V.

    1999-01-01

    The root cap is increasingly appreciated as a complex and dynamic plant organ. Root caps sense and transmit environmental signals, synthesize and secrete small molecules and macromolecules, and in some species shed metabolically active cells. However, it is not known whether root caps are essential for normal shoot and root development. We report the identification of a root cap-specific promoter and describe its use to genetically ablate root caps by directing root cap-specific expression of a diphtheria toxin A-chain gene. Transgenic toxin-expressing plants are viable and have normal aerial parts but agravitropic roots, implying loss of root cap function. Several cell layers are missing from the transgenic root caps, and the remaining cells are abnormal. Although the radial organization of the roots is normal in toxin-expressing plants, the root tips have fewer cytoplasmically dense cells than do wild-type root tips, suggesting that root meristematic activity is lower in transgenic than in wild-type plants. The roots of transgenic plants have more lateral roots and these are, in turn, more highly branched than those of wild-type plants. Thus, root cap ablation alters root architecture both by inhibiting root meristematic activity and by stimulating lateral root initiation. These observations imply that the root caps contain essential components of the signaling system that determines root architecture.

  9. Deriving the unit hydrograph by root selection

    NASA Astrophysics Data System (ADS)

    Turner, J. E.; Dooge, J. C. I.; Bree, T.

    1989-09-01

    De Laine's method of deriving the unit hydrograph from the common roots of polynomials corresponding to different storms is used as a basis for proposing a new procedure in which the unit hydrograph roots can be selected from among the polynomial roots for the runoff of a single storm. The selection is made on the basis that the complex unit hydrograph roots form a characteristic "skew circle" pattern when plotted on an Argand diagram. The application of the procedure to field data is illustrated for both a single-peaked and a double-peaked event.

  10. New substitution models for rooting phylogenetic trees

    PubMed Central

    Williams, Tom A.; Heaps, Sarah E.; Cherlin, Svetlana; Nye, Tom M. W.; Boys, Richard J.; Embley, T. Martin

    2015-01-01

    The root of a phylogenetic tree is fundamental to its biological interpretation, but standard substitution models do not provide any information on its position. Here, we describe two recently developed models that relax the usual assumptions of stationarity and reversibility, thereby facilitating root inference without the need for an outgroup. We compare the performance of these models on a classic test case for phylogenetic methods, before considering two highly topical questions in evolutionary biology: the deep structure of the tree of life and the root of the archaeal radiation. We show that all three alignments contain meaningful rooting information that can be harnessed by these new models, thus complementing and extending previous work based on outgroup rooting. In particular, our analyses exclude the root of the tree of life from the eukaryotes or Archaea, placing it on the bacterial stem or within the Bacteria. They also exclude the root of the archaeal radiation from several major clades, consistent with analyses using other rooting methods. Overall, our results demonstrate the utility of non-reversible and non-stationary models for rooting phylogenetic trees, and identify areas where further progress can be made. PMID:26323766

  11. Maxillary First Molar with Two Root Canals

    PubMed Central

    Rahimi, Saeed; Ghasemi, Negin

    2013-01-01

    Knowledge regarding the anatomic morphology of maxillary molars is absolutely essential for the success of endodontic treatment. The morphology of the permanent maxillary first molar has been reviewed extensively; however, the presence of two canals in a two-rooted maxillary first molar has rarely been reported in studies describing tooth and root canal anatomies. This case report presents a patient with a maxillary first molar with two roots and two root canals, who was referred to the Department of Endodontics, Tabriz University of Medical Sciences, Iran. PMID:23862051

  12. The nth root of sequential effect algebras

    NASA Astrophysics Data System (ADS)

    Shen, Jun; Wu, Junde

    2010-06-01

    In 2005, Gudder [Int. J. Theor. Phys. 44, 2219 (2005)] presented 25 problems of sequential effect algebras, the 20th problem asked: In a sequential effect algebra, if the square root of some element exists, is it unique? In this paper, we show that for each given positive integer n >1, there is a sequential effect algebra such that the nth root of its some element c is not unique, and the nth root of c is not the kth root of c (k

  13. New substitution models for rooting phylogenetic trees.

    PubMed

    Williams, Tom A; Heaps, Sarah E; Cherlin, Svetlana; Nye, Tom M W; Boys, Richard J; Embley, T Martin

    2015-09-26

    The root of a phylogenetic tree is fundamental to its biological interpretation, but standard substitution models do not provide any information on its position. Here, we describe two recently developed models that relax the usual assumptions of stationarity and reversibility, thereby facilitating root inference without the need for an outgroup. We compare the performance of these models on a classic test case for phylogenetic methods, before considering two highly topical questions in evolutionary biology: the deep structure of the tree of life and the root of the archaeal radiation. We show that all three alignments contain meaningful rooting information that can be harnessed by these new models, thus complementing and extending previous work based on outgroup rooting. In particular, our analyses exclude the root of the tree of life from the eukaryotes or Archaea, placing it on the bacterial stem or within the Bacteria. They also exclude the root of the archaeal radiation from several major clades, consistent with analyses using other rooting methods. Overall, our results demonstrate the utility of non-reversible and non-stationary models for rooting phylogenetic trees, and identify areas where further progress can be made. PMID:26323766

  14. Increased symplasmic permeability in barley root epidermal cells correlates with defects in root hair development.

    PubMed

    Marzec, M; Muszynska, A; Melzer, M; Sas-Nowosielska, H; Kurczynska, E U

    2014-03-01

    It is well known that the process of plant cell differentiation depends on the symplasmic isolation of cells. Before starting the differentiation programme, the individual cell or group of cells should restrict symplasmic communication with neighbouring cells. We tested the symplasmic communication between epidermal cells in the different root zones of parental barley plants Hordeum vulgare L., cv. 'Karat' with normal root hair development, and two root hairless mutants (rhl1.a and rhl1.b). The results clearly show that symplasmic communication was limited during root hair differentiation in the parental variety, whereas in both root hairless mutants epidermal cells were still symplasmically connected in the corresponding root zone. This paper is the first report on the role of symplasmic isolation in barley root cell differentiation, and additionally shows that a disturbance in the restriction of symplasmic communication is present in root hairless mutants. PMID:23927737

  15. Increased symplasmic permeability in barley root epidermal cells correlates with defects in root hair development

    PubMed Central

    Marzec, M; Muszynska, A; Melzer, M; Sas-Nowosielska, H; Kurczynska, E U; Wick, S

    2014-01-01

    It is well known that the process of plant cell differentiation depends on the symplasmic isolation of cells. Before starting the differentiation programme, the individual cell or group of cells should restrict symplasmic communication with neighbouring cells. We tested the symplasmic communication between epidermal cells in the different root zones of parental barley plants Hordeum vulgare L., cv. ‘Karat’ with normal root hair development, and two root hairless mutants (rhl1.a and rhl1.b). The results clearly show that symplasmic communication was limited during root hair differentiation in the parental variety, whereas in both root hairless mutants epidermal cells were still symplasmically connected in the corresponding root zone. This paper is the first report on the role of symplasmic isolation in barley root cell differentiation, and additionally shows that a disturbance in the restriction of symplasmic communication is present in root hairless mutants. PMID:23927737

  16. OZONE DECREASES SPRING ROOT GROWTH AND ROOT CARBOHYDRATE CONTENT IN PONDEROSA PINE THE YEAR FOLLOWING EXPOSURE

    EPA Science Inventory

    Storage carbohydrates are extremely important for new shoot and root development following dormancy or during periods of high stress. he hypothesis that ozone decreases carbohydrate storage and decreases new root growth during the year following exposure was investigated. eedling...

  17. Root-growth-inhibiting sheet

    DOEpatents

    Burton, Frederick G.; Cataldo, Dominic A.; Cline, John F.; Skiens, W. Eugene; Van Voris, Peter

    1993-01-01

    In accordance with this invention, a porous sheet material is provided at intervals with bodies of a polymer which contain a 2,6-dinitroaniline. The sheet material is made porous to permit free passage of water. It may be either a perforated sheet or a woven or non-woven textile material. A particularly desirable embodiment is a non-woven fabric of non-biodegradable material. This type of material is known as a "geotextile" and is used for weed control, prevention of erosion on slopes, and other landscaping purposes. In order to obtain a root repelling property, a dinitroaniline is blended with a polymer which is attached to the geotextile or other porous material.

  18. Root-growth-inhibiting sheet

    DOEpatents

    Burton, F.G.; Cataldo, D.A.; Cline, J.F.; Skiens, W.E.; Van Voris, P.

    1993-01-26

    In accordance with this invention, a porous sheet material is provided at intervals with bodies of a polymer which contain a 2,6-dinitroaniline. The sheet material is made porous to permit free passage of water. It may be either a perforated sheet or a woven or non-woven textile material. A particularly desirable embodiment is a non-woven fabric of non-biodegradable material. This type of material is known as a geotextile'' and is used for weed control, prevention of erosion on slopes, and other landscaping purposes. In order to obtain a root repelling property, a dinitroaniline is blended with a polymer which is attached to the geotextile or other porous material.

  19. ROOT CAUSE ANALYSIS PROGRAM MANUAL

    SciTech Connect

    Gravois, Melanie C.

    2007-05-02

    Root Cause Analysis (RCA) identifies the cause of an adverse condition that, if corrected, will preclude recurrence or greatly reduce the probability of recurrence of the same or similar adverse conditions and thereby protect the health and safety of the public, the workers, and the environment. This procedure sets forth the requirements for management determination and the selection of RCA methods and implementation of RCAs that are a result of significant findings from Price-Anderson Amendments Act (PAAA) violations, occurrences/events, Significant Adverse Conditions, and external oversight Corrective Action Requests (CARs) generated by the Office of Enforcement (PAAA headquarters), the U.S. Environmental Protection Agency, and other oversight entities against Lawrence Berkeley National Laboratory (LBNL). Performance of an RCA may result in the identification of issues that should be reported in accordance with the Issues Management Program Manual.

  20. Root hair formation in rice (Oryza sativa L.) differs between root types and is altered in artificial growth conditions.

    PubMed

    Nestler, Josefine; Keyes, Samuel David; Wissuwa, Matthias

    2016-06-01

    Root hairs are important sites for nutrient uptake, especially in P limiting conditions. Here we provide first insights into root hair development for the diverse root types of rice grown under different conditions, and show the first in situ images of rice root hairs in intact soil. Roots of plants grown in upland fields produced short root hairs that showed little responsiveness to P deficiency, and had a higher root hair density in the high P condition. These results were reproducible in rhizoboxes under greenhouse conditions. Synchrotron-based in situ analysis of root hairs in intact soil further confirmed this pattern of root hair formation. In contrast, plants grown in nutrient solution produced more and longer root hairs in low P conditions, but these were unequally distributed among the different root types. While nutrient solution-grown main roots had longer hairs compared to upland field-grown main roots, second order lateral roots did not form any root hairs in nutrient solution-grown plants. Furthermore, root hair formation for plants grown in flooded lowland fields revealed few similarities with those grown in nutrient solution, thus defining nutrient solution as a possible measure of maximal, but not natural root hair development. By combining root hair length and density as a measure for root hair impact on the whole soil-grown root system we show that lateral roots provided the majority of root hair surface. PMID:26976815

  1. Malformations of the tooth root in humans.

    PubMed

    Luder, Hans U

    2015-01-01

    The most common root malformations in humans arise from either developmental disorders of the root alone or disorders of radicular development as part of a general tooth dysplasia. The aim of this review is to relate the characteristics of these root malformations to potentially disrupted processes involved in radicular morphogenesis. Radicular morphogenesis proceeds under the control of Hertwig's epithelial root sheath (HERS) which determines the number, length, and shape of the root, induces the formation of radicular dentin, and participates in the development of root cementum. Formation of HERS at the transition from crown to root development appears to be very insensitive to adverse effects, with the result that rootless teeth are extremely rare. In contrast, shortened roots as a consequence of impaired or prematurely halted apical growth of HERS constitute the most prevalent radicular dysplasia which occurs due to trauma and unknown reasons as well as in association with dentin disorders. While odontoblast differentiation inevitably stops when growth of HERS is arrested, it seems to be unaffected even in cases of severe dentin dysplasias such as regional odontodysplasia and dentin dysplasia type I. As a result radicular dentin formation is at least initiated and progresses for a limited time. The only condition affecting cementogenesis is hypophosphatasia which disrupts the formation of acellular cementum through an inhibition of mineralization. A process particularly susceptible to adverse effects appears to be the formation of the furcation in multirooted teeth. Impairment or disruption of this process entails taurodontism, single-rooted posterior teeth, and misshapen furcations. Thus, even though many characteristics of human root malformations can be related to disorders of specific processes involved in radicular morphogenesis, precise inferences as to the pathogenesis of these dysplasias are hampered by the still limited knowledge on root formation

  2. Malformations of the tooth root in humans

    PubMed Central

    Luder, Hans U.

    2015-01-01

    The most common root malformations in humans arise from either developmental disorders of the root alone or disorders of radicular development as part of a general tooth dysplasia. The aim of this review is to relate the characteristics of these root malformations to potentially disrupted processes involved in radicular morphogenesis. Radicular morphogenesis proceeds under the control of Hertwig's epithelial root sheath (HERS) which determines the number, length, and shape of the root, induces the formation of radicular dentin, and participates in the development of root cementum. Formation of HERS at the transition from crown to root development appears to be very insensitive to adverse effects, with the result that rootless teeth are extremely rare. In contrast, shortened roots as a consequence of impaired or prematurely halted apical growth of HERS constitute the most prevalent radicular dysplasia which occurs due to trauma and unknown reasons as well as in association with dentin disorders. While odontoblast differentiation inevitably stops when growth of HERS is arrested, it seems to be unaffected even in cases of severe dentin dysplasias such as regional odontodysplasia and dentin dysplasia type I. As a result radicular dentin formation is at least initiated and progresses for a limited time. The only condition affecting cementogenesis is hypophosphatasia which disrupts the formation of acellular cementum through an inhibition of mineralization. A process particularly susceptible to adverse effects appears to be the formation of the furcation in multirooted teeth. Impairment or disruption of this process entails taurodontism, single-rooted posterior teeth, and misshapen furcations. Thus, even though many characteristics of human root malformations can be related to disorders of specific processes involved in radicular morphogenesis, precise inferences as to the pathogenesis of these dysplasias are hampered by the still limited knowledge on root formation

  3. Root-soil relationships and terroir

    NASA Astrophysics Data System (ADS)

    Tomasi, Diego

    2015-04-01

    Soil features, along with climate, are among the most important determinants of a succesful grape production in a certain area. Most of the studies, so far, investigated the above-ground vine response to differente edaphic and climate condition, but it is clearly not sufficient to explain the vine whole behaviour. In fact, roots represent an important part of the terroir system (soil-plant-atmosphere-man), and their study can provide better comprehension of vine responses to different environments. The root density and distribution, the ability of deep-rooting and regenerating new roots are good indicators of root well-being, and represents the basis for an efficient physiological activity of the root system. Root deepening and distribution are strongly dependent and sensitive on soil type and soil properties, while root density is affected mostly by canopy size, rootstock and water availability. According to root well-being, soil management strategies should alleviate soil impediments, improving aeration and microbial activity. Moreover, agronomic practices can impact root system performance and influence the above-ground growth. It is well known, for example, that the root system size is largely diminished by high planting densities. Close vine spacings stimulate a more effective utilization of the available soil, water and nutrients, but if the competition for available soil becomes too high, it can repress vine growth, and compromise vineyard longevity, productivity and reaction to growing season weather. Development of resilient rootstocks, more efficient in terms of water and nutrient uptake and capable of dealing with climate and soil extremes (drought, high salinity) are primary goals fore future research. The use of these rootstocks will benefit a more sustainable use of the soil resources and the preservation and valorisation of the terroir.

  4. Root reinforcement of soils under compression

    NASA Astrophysics Data System (ADS)

    Schwarz, M.; Rist, A.; Cohen, D.; Giadrossich, F.; Egorov, P.; Büttner, D.; Stolz, M.; Thormann, J.-J.

    2015-10-01

    It is well recognized that roots reinforce soils and that the distribution of roots within vegetated hillslopes strongly influences the spatial distribution of soil strength. Previous studies have focussed on the contribution of root reinforcement under conditions of tension or shear. However, no systematic investigation into the contribution of root reinforcement to soils experiencing compression, such as the passive Earth forces at the toe of a landslide, is found in the literature. An empirical-analytical model (CoRoS) for the quantification of root reinforcement in soils under compression is presented and tested against experimental data. The CoRoS model describes the force-displacement behavior of compressed, rooted soils and can be used to provide a framework for improving slope stability calculations. Laboratory results showed that the presence of 10 roots with diameters ranging from 6 to 28 mm in a rectangular soil profile 0.72 m by 0.25 m increased the compressive strength of the soil by about 40% (2.5 kN) at a displacement of 0.05 m, while the apparent stiffness of the rooted soil was 38% higher than for root-free soil. The CoRoS model yields good agreement with experimentally determined values of maximum reinforcement force and compression force as a function of displacement. These results indicate that root reinforcement under compression has a major influence on the mechanical behavior of soil and that the force-displacement behavior of roots should be included in analysis of the compressive regimes that commonly are present in the toe of landslides.

  5. Root susceptibility and inoculum production from roots of Eastern United States oak species to Phytophthora ramorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about root susceptibility of eastern U.S. tree species to Phytophthora ramorum. In this study, we examined root susceptibility and inoculum production from roots. Sprouted acorns of Q. rubra, Q. palustrus, Q. coccinia, Q. alba, Q. michauxii and Q. prinus were exposed to motile zoos...

  6. RootScan: Software for high-throughput analysis of root anatomical traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    RootScan is a program for semi-automated image analysis of anatomical phenes in root cross-sections. RootScan uses pixel value thresholds to separate the cross-section from its background and to visually dissect it into tissue regions. Area measurements and object counts are performed within various...

  7. Effect of Root Moisture Content and Diameter on Root Tensile Properties

    PubMed Central

    Yang, Yuanjun; Chen, Lihua; Li, Ning; Zhang, Qiufen

    2016-01-01

    The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tree species. Betula platyphylla, Quercus mongolica, Pinus tabulaeformis, and Larix gmelinii, the most popular tree species used for slope stabilization in the rocky mountainous areas of northern China, were used in this study. A tensile test was conducted after root samples were grouped by diameter and moisture content. The results showedthat:1) root moisture content had a significant influence on tensile properties; 2) slightly loss of root moisture content could enhance tensile strength, but too much loss of water resulted in weaker capacity for root elongation, and consequently reduced tensile strength; 3) root diameter had a strong positive correlation with tensile resistance; and4) the roots of Betula platyphylla had the best tensile properties when both diameter and moisture content being controlled. These findings improve our understanding of root tensile properties with root size and moisture, and could be useful for slope stabilization using vegetation. PMID:27003872

  8. Root susceptibility and inoculum production from roots of eastern oak species to Phytophthora ramorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about root susceptibility of eastern tree species to Phytophthora ramorum. In this study, we examined root susceptibility and inoculum production from roots. Oak radicles of several eastern oak species were exposed to zoospore suspensions of 1, 10, 100, or 1000 zoospores per ml at ...

  9. Root-Gel Interactions and the Root Waving Behavior of Arabidopsis1[w

    PubMed Central

    Thompson, Matthew V.; Holbrook, N. Michele

    2004-01-01

    Arabidopsis roots grown on inclined agarose gels exhibit a sinusoidal growth pattern known as root waving. While root waving has been attributed to both intrinsic factors (e.g. circumnutation) and growth responses to external signals such as gravity, the potential for physical interactions between the root and its substrate to influence the development of this complex phenotype has been generally ignored. Using a rotating stage microscope and time-lapse digital imaging, we show that (1) root tip mobility is impeded by the gel surface, (2) this impedance causes root tip deflections by amplifying curvature in the elongation zone in a way that is distinctly nontropic, and (3) root tip impedance is augmented by normal gravitropic pressure applied by the root tip against the gel surface. Thus, both lateral corrective bending near the root apex and root tip impedance could be due to different vector components of the same graviresponse. Furthermore, we speculate that coupling between root twisting and bending is a mechanical effect resulting from root tip impedance. PMID:15247406

  10. Kinetics of short-term root-carbon mineralization in roots of biofuel crops in soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To better understand and document the rates of root decomposition in biofuel cropping systems, we compared the evolution of CO2 from roots incubated with samples of two Iowa Mollisols. Root samples were collected from experimental plots for four cropping systems: a multispecies reconstructed prairie...

  11. Effect of Root Moisture Content and Diameter on Root Tensile Properties.

    PubMed

    Yang, Yuanjun; Chen, Lihua; Li, Ning; Zhang, Qiufen

    2016-01-01

    The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tree species. Betula platyphylla, Quercus mongolica, Pinus tabulaeformis, and Larix gmelinii, the most popular tree species used for slope stabilization in the rocky mountainous areas of northern China, were used in this study. A tensile test was conducted after root samples were grouped by diameter and moisture content. The results showedthat:1) root moisture content had a significant influence on tensile properties; 2) slightly loss of root moisture content could enhance tensile strength, but too much loss of water resulted in weaker capacity for root elongation, and consequently reduced tensile strength; 3) root diameter had a strong positive correlation with tensile resistance; and4) the roots of Betula platyphylla had the best tensile properties when both diameter and moisture content being controlled. These findings improve our understanding of root tensile properties with root size and moisture, and could be useful for slope stabilization using vegetation. PMID:27003872

  12. Relations between Roots and Coefficients of Cubic Equations with One Root Negative the Reciprocal of Another

    ERIC Educational Resources Information Center

    Asiru, M. A.

    2007-01-01

    Under predetermined conditions on the roots and coefficients, necessary and sufficient conditions relating the coefficients of a given cubic equation x[cubed] + ax[squared] + bx + c = 0 can be established so that the roots possess desired properties. In this note, the condition for one root of a cubic equation to be "the negative reciprocal of…

  13. Coupling root architecture and pore network modeling - an attempt towards better understanding root-soil interactions

    NASA Astrophysics Data System (ADS)

    Leitner, Daniel; Bodner, Gernot; Raoof, Amir

    2013-04-01

    Understanding root-soil interactions is of high importance for environmental and agricultural management. Root uptake is an essential component in water and solute transport modeling. The amount of groundwater recharge and solute leaching significantly depends on the demand based plant extraction via its root system. Plant uptake however not only responds to the potential demand, but in most situations is limited by supply form the soil. The ability of the plant to access water and solutes in the soil is governed mainly by root distribution. Particularly under conditions of heterogeneous distribution of water and solutes in the soil, it is essential to capture the interaction between soil and roots. Root architecture models allow studying plant uptake from soil by describing growth and branching of root axes in the soil. Currently root architecture models are able to respond dynamically to water and nutrient distribution in the soil by directed growth (tropism), modified branching and enhanced exudation. The porous soil medium as rooting environment in these models is generally described by classical macroscopic water retention and sorption models, average over the pore scale. In our opinion this simplified description of the root growth medium implies several shortcomings for better understanding root-soil interactions: (i) It is well known that roots grow preferentially in preexisting pores, particularly in more rigid/dry soil. Thus the pore network contributes to the architectural form of the root system; (ii) roots themselves can influence the pore network by creating preferential flow paths (biopores) which are an essential element of structural porosity with strong impact on transport processes; (iii) plant uptake depend on both the spatial location of water/solutes in the pore network as well as the spatial distribution of roots. We therefore consider that for advancing our understanding in root-soil interactions, we need not only to extend our root models

  14. Effect of Root System Morphology on Root-sprouting and Shoot-rooting Abilities in 123 Plant Species from Eroded Lands in North-east Spain

    PubMed Central

    GUERRERO-CAMPO, JOAQUÍN; PALACIO, SARA; PÉREZ-RONTOMÉ, CARMEN; MONTSERRAT-MARTÍ, GABRIEL

    2006-01-01

    • Background and Aims The objective of this study was to test whether the mean values of several root morphological variables were related to the ability to develop root-borne shoots and/or shoot-borne roots in a wide range of vascular plants. • Methods A comparative study was carried out on the 123 most common plant species from eroded lands in north-east Spain. After careful excavations in the field, measurements were taken of the maximum root depth, absolute and relative basal root diameter, specific root length (SRL), and the root depth/root lateral spread ratio on at least three individuals per species. Shoot-rooting and root-sprouting were observed in a large number of individuals in many eroded and sedimentary environments. The effect of life history and phylogeny on shoot-rooting and root-sprouting abilities was also analysed. • Key Results The species with coarse and deep tap-roots tended to be root-sprouting and those with fine, fasciculate and long main roots (which generally spread laterally), tended to be shoot-rooting. Phylogeny had an important influence on root system morphology and shoot-rooting and root-sprouting capacities. However, the above relations stood after applying analyses based on phylogenetically independent contrasts (PICs). • Conclusions The main morphological features of the root system of the study species are related to their ability to sprout from their roots and form roots from their shoots. According to the results, such abilities might only be functionally viable in restricted root system morphologies and ecological strategies. PMID:16790468

  15. Meniscal Root Tears: Identification and Repair.

    PubMed

    Doherty, David B; Lowe, Walter R

    2016-01-01

    Intact menisci are capable of converting the axial load of tibiofemoral contact into hoop stress that protects the knee joint. Total meniscectomy leads to rapid degeneration of the knee. Strong clinical and biomechanical data show meniscal root tears and avulsions are the functional equivalent of total meniscectomy. Lateral root tears commonly occur with knee ligament sprains and tears. Medial root tears are generally more chronic, and can be caused by preexisting knee arthritis. Meniscal root repair is indicated when there is identification of a meniscal root tear in a knee with minimal to no arthritis. Chronic root tears in the setting of osteoarthritis are treated conservatively. Meniscal root tears can acutely occur with cruciate ligament tears, can exaggerate symptoms of instability, and will have negative ramifications on outcomes of anterior cruciate ligament reconstruction if not addressed concomitantly. In this review, we describe the importance of the menisci for knee joint longevity through anatomy and biomechanics, the diagnostic workup, and ultimately a transosseous technique for repair of meniscal root tears and avulsions. PMID:27004274

  16. ADVANCING FINE ROOT RESEARCH WITH MINIRHIZOTRONS

    EPA Science Inventory

    Minirhizotrons provide a nondestructive, in situ method for directly viewing and studying fine roots. Although many insights into fine roots have been gained using minirhizotrons, it is clear from the literature that there is still wide variation in how minirhizotrons and minirhi...

  17. Fate of HERS during Tooth Root Development

    PubMed Central

    Huang, Xiaofeng; Bringas, Pablo; Slavkin, Harold C.; Chai, Yang

    2009-01-01

    Tooth root development begins after the completion of crown formation in mammals. Previous studies have shown that Hertwig's epithelial root sheath (HERS) plays an important role in root development, but the fate of HERS has remained unknown. In order to investigate the morphological fate and analyze the dynamic movement of HERS cells in vivo, we generated K14-Cre;R26R mice. HERS cells are detectable on the surface of the root throughout root formation and do not disappear. Most of the HERS cells are attached to the surface of the cementum, and others separate to become the epithelial rest of Malasez. HERS cells secrete extracellular matrix components onto the surface of the dentin before dental follicle cells penetrate the HERS network to contact dentin. HERS cells also participate in the cementum development and may differentiate into cementocytes. During root development, the HERS is not interrupted, and instead the HERS cells continue to communicate with each other through the network structure. Furthermore, HERS cells interact with cranial neural crest derived mesenchyme to guide root development. Taken together, the network of HERS cells is crucial for tooth root development. PMID:19576204

  18. 33 CFR 117.1095 - Root River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Root River. 117.1095 Section 117.1095 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Wisconsin § 117.1095 Root River. (a) The draw of the Main...

  19. 33 CFR 117.1095 - Root River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Root River. 117.1095 Section 117.1095 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Wisconsin § 117.1095 Root River. (a) The draw of the Main...

  20. 33 CFR 117.1095 - Root River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Root River. 117.1095 Section 117.1095 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Wisconsin § 117.1095 Root River. (a) The draw of the Main...

  1. 33 CFR 117.1095 - Root River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Root River. 117.1095 Section 117.1095 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Wisconsin § 117.1095 Root River. (a) The draw of the Main...

  2. Enhancing Students' Understanding of Square Roots

    ERIC Educational Resources Information Center

    Wiesman, Jeff L.

    2015-01-01

    Students enrolled in a middle school prealgebra or algebra course often struggle to conceptualize and understand the meaning of radical notation when it is introduced. For example, although it is important for students to approximate the decimal value of a number such as [square root of] 30 and estimate the value of a square root in the form of…

  3. Sporulation on plant roots by Phytophthora ramorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytophthora ramorum has been shown to infect the roots of many of the pathogen’s foliar hosts. Methods of detecting inoculum in runoff and of quantifying root colonization were tested using Viburnum tinus, Camellia oleifera, Quercus prinus, Umbellularia californica, and Epilobium ciliatum. Plants...

  4. Cytological and ultrastructural studies on root tissues

    NASA Technical Reports Server (NTRS)

    Slocum, R. D.; Gaynor, J. J.; Galston, A. W.

    1984-01-01

    The anatomy and fine structure of roots from oat and mung bean seedlings, grown under microgravity conditions for 8 days aboard the Space Shuttle, was examined and compared to that of roots from ground control plants grown under similar conditions. Roots from both sets of oat seedlings exhibited characteristic monocotyledonous tissue organization and normal ultrastructural features, except for cortex cell mitochondria, which exhibited a 'swollen' morphology. Various stages of cell division were observed in the meristematic tissues of oat roots. Ground control and flight-grown mung bean roots also showed normal tissue organization, but root cap cells in the flight-grown roots were collapsed and degraded in appearance, especially at the cap periphery. At the ultrastructural level, these cells exhibited a loss of organelle integrity and a highly-condensed cytoplasm. This latter observation perhaps suggests a differing tissue sensitivity for the two species to growth conditions employed in space flight. The basis for abnormal root cap cell development is not understood, but the loss of these putative gravity-sensing cells holds potential significance for long term plant growth orientation during space flight.

  5. Growth and development of root system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The growth and development of root systems of cotton plants is under genetic control but may be modified by the environment. There are many factors that influence root development in cotton. These range from abiotic factors such as soil temperature, soil water, and soil aeration to biotic factors ...

  6. Field investigation of rooting potential in sorghum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The differential influence of root systems on plant development under field conditions is very difficult. A field experiment was devised using three different row spacings (101,152 and 203 cm ) to screen sorghum germplasm for rooting potential based on the relative ability to explore additional soil...

  7. Affine root systems and dual numbers

    NASA Astrophysics Data System (ADS)

    Kostyakov, I. V.; Gromov, N. A.; Kuratov, V. V.

    The root systems in Carroll spaces with degenerate metric are defined. It is shown that their Cartan matrices and reflection groups are affine. Due to the geometric consideration the root system structure of affine algebras is determined by a sufficiently simple algorithm.

  8. Black streak root rot of lentil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Black streak root rot of lentil is caused by the soil borne fungus Thielaviopsis basicola. The pathogen is widespread. The disease shows symptoms of black streaking on root, and stunted plants. The disease is favored by cool and moist weather. Management of the disease rely on avoiding fields wi...

  9. Root phenotypic characterization of lesquerella genetic resources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Root systems are crucial for optimizing plant growth and productivity. There has been a push to better understand root morphological and architectural traits and their plasticity because these traits determine the capacity of plants to effectively acquire available water and soil nutrients in the so...

  10. Maize root characteristis that enhance flooding tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant root systems have several cellular and molecular adaptations that are important in reducing stress caused by flooding. Of these, two physical properties of root systems provide an initial barrier toward the avoidance of stress. These are the presence of aerenchyma cells and rapid adventitious ...

  11. Sugarbeet Cultivar Evaluation for Bacterial Root Rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial root rot of sugarbeet caused by Leuconostoc mesenteroides subsp. dextranicum is a disease problem recently described in the United States. To ameliorate the impact of bacterial root rot on sucrose loss in the field, storage piles, and factories, studies were conducted to establish an assa...

  12. 33 CFR 117.1095 - Root River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Root River. 117.1095 Section 117.1095 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Wisconsin § 117.1095 Root River. (a) The draw of the Main...

  13. Rapid phenotyping of alfalfa root system architecture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Root system architecture (RSA) influences the capacity of an alfalfa plant for symbiotic nitrogen fixation, nutrient uptake and water use efficiency, resistance to frost heaving, winterhardiness, and some pest and pathogen resistance. However, we currently lack a basic understanding of root system d...

  14. Roots as a source of food.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous plant species produce edible roots that are an important source of calories and that contribute to human nutrition. This book chapter discusses the origin and domestication, production aspects and nutritional aspects of a number of root crops including; cassava (Manioc), sweetpotato (Ipomo...

  15. A new approach to root formation

    PubMed Central

    Vatanpour, Mehdi; Zarei, Mina; Javidi, Maryam; Shirazian, Shiva

    2008-01-01

    In endodontics, treatment of an open apex tooth with necrotic pulp is a problem. It seems that with promotion of remnants of Hertwig’s epithelial sheath or rest of malassez accompany with a good irrigation of root canal we can expect root formation. (Iranian Endodontic Journal 2008;3:42-43) PMID:24171018

  16. ACETOGENIC BACTERIA ASSOCIATED WITH SEAGRASS ROOTS

    EPA Science Inventory

    Seagrasses are adapted to being rooted in reduced, anoxic sediments with high rates of sulfate reduction. During the day, an oxygen gradient is generated around the roots, becoming anoxic at night. Thus, obligate anaerobic bacteria in the rhizosphere have to tolerate elevated oxy...

  17. Dehydration Accelerates Respiration in Postharvest Sugarbeet Roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugarbeet (Beta vulgaris L.) roots lose water during storage and often become severely dehydrated after prolonged storage and at the outer regions of storage piles which have greater wind and sun exposure. Sucrose loss is known to be elevated in dehydrated roots, although the metabolic processes re...

  18. Method for Constructing Standardized Simulated Root Canals.

    ERIC Educational Resources Information Center

    Schulz-Bongert, Udo; Weine, Franklin S.

    1990-01-01

    The construction of visual and manipulative aids, clear resin blocks with root-canal-like spaces, for simulation of root canals is explained. Time, materials, and techniques are discussed. The method allows for comparison of canals, creation of any configuration of canals, and easy presentation during instruction. (MSE)

  19. Arabidopsis: An Adequate Model for Dicot Root Systems?

    PubMed

    Zobel, Richard W

    2016-01-01

    The Arabidopsis root system is frequently considered to have only three classes of root: primary, lateral, and adventitious. Research with other plant species has suggested up to eight different developmental/functional classes of root for a given plant root system. If Arabidopsis has only three classes of root, it may not be an adequate model for eudicot plant root systems. Recent research, however, can be interpreted to suggest that pre-flowering Arabidopsis does have at least five (5) of these classes of root. This then suggests that Arabidopsis root research can be considered an adequate model for dicot plant root systems. PMID:26904040

  20. GiA Roots: software for the high throughput analysis of plant root system architecture

    PubMed Central

    2012-01-01

    Background Characterizing root system architecture (RSA) is essential to understanding the development and function of vascular plants. Identifying RSA-associated genes also represents an underexplored opportunity for crop improvement. Software tools are needed to accelerate the pace at which quantitative traits of RSA are estimated from images of root networks. Results We have developed GiA Roots (General Image Analysis of Roots), a semi-automated software tool designed specifically for the high-throughput analysis of root system images. GiA Roots includes user-assisted algorithms to distinguish root from background and a fully automated pipeline that extracts dozens of root system phenotypes. Quantitative information on each phenotype, along with intermediate steps for full reproducibility, is returned to the end-user for downstream analysis. GiA Roots has a GUI front end and a command-line interface for interweaving the software into large-scale workflows. GiA Roots can also be extended to estimate novel phenotypes specified by the end-user. Conclusions We demonstrate the use of GiA Roots on a set of 2393 images of rice roots representing 12 genotypes from the species Oryza sativa. We validate trait measurements against prior analyses of this image set that demonstrated that RSA traits are likely heritable and associated with genotypic differences. Moreover, we demonstrate that GiA Roots is extensible and an end-user can add functionality so that GiA Roots can estimate novel RSA traits. In summary, we show that the software can function as an efficient tool as part of a workflow to move from large numbers of root images to downstream analysis. PMID:22834569

  1. Effect of lead on root growth

    PubMed Central

    Fahr, Mouna; Laplaze, Laurent; Bendaou, Najib; Hocher, Valerie; Mzibri, Mohamed El; Bogusz, Didier; Smouni, Abdelaziz

    2013-01-01

    Lead (Pb) is one of the most widespread heavy metal contaminant in soils. It is highly toxic to living organisms. Pb has no biological function but can cause morphological, physiological, and biochemical dysfunctions in plants. Plants have developed a wide range of tolerance mechanisms that are activated in response to Pb exposure. Pb affects plants primarily through their root systems. Plant roots rapidly respond either (i) by the synthesis and deposition of callose, creating a barrier that stops Pb entering (ii) through the uptake of large amounts of Pb and its sequestration in the vacuole accompanied by changes in root growth and branching pattern or (iii) by its translocation to the aboveground parts of plant in the case of hyperaccumulators plants. Here we review the interactions of roots with the presence of Pb in the rhizosphere and the effect of Pb on the physiological and biochemical mechanisms of root development. PMID:23750165

  2. Systems approaches to study root architecture dynamics

    PubMed Central

    Cuesta, Candela; Wabnik, Krzysztof; Benková, Eva

    2013-01-01

    The plant root system is essential for providing anchorage to the soil, supplying minerals and water, and synthesizing metabolites. It is a dynamic organ modulated by external cues such as environmental signals, water and nutrients availability, salinity and others. Lateral roots (LRs) are initiated from the primary root post-embryonically, after which they progress through discrete developmental stages which can be independently controlled, providing a high level of plasticity during root system formation. Within this review, main contributions are presented, from the classical forward genetic screens to the more recent high-throughput approaches, combined with computer model predictions, dissecting how LRs and thereby root system architecture is established and developed. PMID:24421783

  3. The origin and early evolution of roots.

    PubMed

    Kenrick, Paul; Strullu-Derrien, Christine

    2014-10-01

    Geological sites of exceptional fossil preservation are becoming a focus of research on root evolution because they retain edaphic and ecological context, and the remains of plant soft tissues are preserved in some. New information is emerging on the origins of rooting systems, their interactions with fungi, and their nature and diversity in the earliest forest ecosystems. Remarkably well-preserved fossils prove that mycorrhizal symbionts were diverse in simple rhizoid-based systems. Roots evolved in a piecemeal fashion and independently in several major clades through the Devonian Period (416 to 360 million years ago), rapidly extending functionality and complexity. Evidence from extinct arborescent clades indicates that polar auxin transport was recruited independently in several to regulate wood and root development. The broader impact of root evolution on the geochemical carbon cycle is a developing area and one in which the interests of the plant physiologist intersect with those of the geochemist. PMID:25187527

  4. Long-term control of root growth

    DOEpatents

    Burton, Frederick G.; Cataldo, Dominic A.; Cline, John F.; Skiens, W. Eugene

    1992-05-26

    A method and system for long-term control of root growth without killing the plants bearing those roots involves incorporating a 2,6-dinitroaniline in a polymer and disposing the polymer in an area in which root control is desired. This results in controlled release of the substituted aniline herbicide over a period of many years. Herbicides of this class have the property of preventing root elongation without translocating into other parts of the plant. The herbicide may be encapsulated in the polymer or mixed with it. The polymer-herbicide mixture may be formed into pellets, sheets, pipe gaskets, pipes for carrying water, or various other forms. The invention may be applied to other protection of buried hazardous wastes, protection of underground pipes, prevention of root intrusion beneath slabs, the dwarfing of trees or shrubs and other applications. The preferred herbicide is 4-difluoromethyl-N,N-dipropyl-2,6-dinitro-aniline, commonly known as trifluralin.

  5. Long-term control of root growth

    SciTech Connect

    Burton, F.G.; Cataldo, D.A.; Cline, J.F.; Skiens, W.E.

    1992-05-26

    A method and system for long-term control of root growth without killing the plants bearing those roots involves incorporating a 2,6-dinitroaniline in a polymer and disposing the polymer in an area in which root control is desired. This results in controlled release of the substituted aniline herbicide over a period of many years. Herbicides of this class have the property of preventing root elongation without translocating into other parts of the plant. The herbicide may be encapsulated in the polymer or mixed with it. The polymer-herbicide mixture may be formed into pellets, sheets, pipe gaskets, pipes for carrying water, or various other forms. The invention may be applied to other protection of buried hazardous wastes, protection of underground pipes, prevention of root intrusion beneath slabs, the dwarfing of trees or shrubs and other applications. The preferred herbicide is 4-difluoromethyl-N,N-dipropyl-2,6-dinitro-aniline, commonly known as trifluralin. 7 figs.

  6. Clinical management of infected root canal dentin.

    PubMed

    Love, R M

    1996-08-01

    Several hundred different species of bacteria are present in the human intraoral environment. Bacterial penetration of root canal dentin occurs when bacteria invade the root canal system. These bacteria may constitute a reservoir from which root canal reinfection may occur during or after endodontic treatment. The learning objective of this article is to review endodontic microbiology, update readers on the role of bacteria in pulp and periapical disease, and discuss the principles of management of infected root canal dentin. Complete debridement, removal of microorganisms and affected dentin, and chemomechanical cleansing of the root canal are suggested as being the cornerstones of successful endodontic therapy, followed by intracanal medication to remove residual bacteria, when required. PMID:9242125

  7. Management of Six Root Canals in Mandibular First Molar

    PubMed Central

    Gomes, Fabio de Almeida; Sousa, Bruno Carvalho

    2015-01-01

    Success in root canal treatment is achieved after thorough cleaning, shaping, and obturation of the root canal system. This clinical case describes conventional root canal treatment of an unusual mandibular first molar with six root canals. The prognosis for endodontic treatment in teeth with abnormal morphology is unfavorable if the clinician fails to recognize extra root canals. PMID:25685156

  8. Root Canal Treatment of a Maxillary Second Premolar with Two Palatal Root Canals: A Case Report

    PubMed Central

    Golmohammadi, Maryam; Jafarzadeh, Hamid

    2016-01-01

    Accurate diagnosis of the root canal morphology and anatomy is essential for thorough shaping and cleaning of the entire root canal system and consequent successful treatment. This report describes a case of maxillary second premolar with two roots and three root canals (two mesial and distal palatal canals). The case report underlines the importance of complete knowledge about root canal morphology and possible variations, coupled with clinical and radiographic examination in order to increase the ability of clinicians to treat difficult cases. PMID:27471538

  9. Root Canal Treatment of a Maxillary Second Premolar with Two Palatal Root Canals: A Case Report.

    PubMed

    Golmohammadi, Maryam; Jafarzadeh, Hamid

    2016-01-01

    Accurate diagnosis of the root canal morphology and anatomy is essential for thorough shaping and cleaning of the entire root canal system and consequent successful treatment. This report describes a case of maxillary second premolar with two roots and three root canals (two mesial and distal palatal canals). The case report underlines the importance of complete knowledge about root canal morphology and possible variations, coupled with clinical and radiographic examination in order to increase the ability of clinicians to treat difficult cases. PMID:27471538

  10. Variation in root density along stream banks.

    PubMed

    Wynn, Theresa M; Mostaghimi, Saied; Burger, James A; Harpold, Adrian A; Henderson, Marc B; Henry, Leigh-Anne

    2004-01-01

    While it is recognized that vegetation plays a significant role in stream bank stabilization, the effects are not fully quantified. The study goal was to determine the type and density of vegetation that provides the greatest protection against stream bank erosion by determining the density of roots in stream banks. To quantify the density of roots along alluvial stream banks, 25 field sites in the Appalachian Mountains were sampled. The riparian buffers varied from short turfgrass to mature riparian forests, representing a range of vegetation types. Root length density (RLD) with depth and aboveground vegetation density were measured. The sites were divided into forested and herbaceous groups and differences in root density were evaluated. At the herbaceous sites, very fine roots (diameter < 0.5 mm) were most common and more than 75% of all roots were concentrated in the upper 30 cm of the stream bank. Under forested vegetation, fine roots (0.5 mm < diameter < 2.0 mm) were more common throughout the bank profile, with 55% of all roots in the top 30 cm. In the top 30 cm of the bank, herbaceous sites had significantly greater overall RLD than forested sites (alpha = 0.01). While there were no significant differences in total RLD below 30 cm, forested sites had significantly greater concentrations of fine roots, as compared with herbaceous sites (alpha = 0.01). As research has shown that erosion resistance has a direct relationship with fine root density, forested vegetation may provide better protection against stream bank erosion. PMID:15537925

  11. Root conditioning in periodontology — Revisited

    PubMed Central

    Nanda, Tarun; Jain, Sanjeev; Kaur, Harjit; Kapoor, Daljit; Nanda, Sonia; Jain, Rohit

    2014-01-01

    Objective: Root surfaces of periodontitis-affected teeth are hypermineralized and contaminated with cytotoxic and other biologically active substances. To achieve complete decontamination of the tooth surfaces, various methods including root conditioning following scaling and root planning are present. The main objective of this article is to throw light on the different root conditioning agents used and the goals accomplished by root conditioning in the field of periodontology. Materials and Methods: 20 human maxillary anterior teeth indicated for extraction due to chronic periodontitis were collected and root planned. The teeth were sectioned and specimens were divided into two groups — Group I and II. Group I dentin specimens were treated with EDTA and group II specimens were treated with tetracycline HCl solution at concentration of 10% by active burnishing technique for 3 minutes. The root surface samples were then examined by scanning electron microscope (SEM). Results: The results of the study showed that EDTA and tetracycline HCl were equally effective in removing the smear layer. It was observed that the total and patent dentinal tubules were more in number in teeth treated with tetracycline as compared to EDTA group. However, EDTA was found to be much more effective as root conditioning agent because it enlarged the diameter of dentinal tubules more than that of tetracycline HCl. Conclusion: Results of in-vitro study showed that both the agents are good root conditioning agents if applied in addition to periodontal therapy. However, further studies are required to establish the in-vivo importance of EDTA and tetracycline HCL as root conditioners. PMID:25097414

  12. Accessory roots and root canals in human anterior teeth: a review and clinical considerations.

    PubMed

    Ahmed, H M A; Hashem, A A

    2016-08-01

    Anterior teeth may have aberrant anatomical variations in the number of roots and root canals. A review of the literature was conducted using appropriate key words in major endodontic journals to identify the available reported cases as well as experimental and clinical investigations on accessory roots and root canals in anterior teeth. After retrieving the full text of related articles, cross-citations were identified, and the pooled data were then discussed. Results revealed a higher prevalence in accessory root/root canal variations in mandibular anterior teeth than in maxillary counterparts. However, maxillary incisor teeth revealed the highest tendency for accessory root/root canal aberrations caused by anomalies such as dens invaginatus and palato-gingival groove. Primary anterior teeth may also exhibit external and internal anatomical variations in the root, especially maxillary canines. Therefore, dental practitioners should thoroughly assess all teeth scheduled for root canal treatment to prevent the undesirable consequences caused by inadequate debridement of accessory configurations of the root canal system. PMID:26174943

  13. RootGraph: a graphic optimization tool for automated image analysis of plant roots

    PubMed Central

    Cai, Jinhai; Zeng, Zhanghui; Connor, Jason N.; Huang, Chun Yuan; Melino, Vanessa; Kumar, Pankaj; Miklavcic, Stanley J.

    2015-01-01

    This paper outlines a numerical scheme for accurate, detailed, and high-throughput image analysis of plant roots. In contrast to existing root image analysis tools that focus on root system-average traits, a novel, fully automated and robust approach for the detailed characterization of root traits, based on a graph optimization process is presented. The scheme, firstly, distinguishes primary roots from lateral roots and, secondly, quantifies a broad spectrum of root traits for each identified primary and lateral root. Thirdly, it associates lateral roots and their properties with the specific primary root from which the laterals emerge. The performance of this approach was evaluated through comparisons with other automated and semi-automated software solutions as well as against results based on manual measurements. The comparisons and subsequent application of the algorithm to an array of experimental data demonstrate that this method outperforms existing methods in terms of accuracy, robustness, and the ability to process root images under high-throughput conditions. PMID:26224880

  14. Root hair-specific expansins modulate root hair elongation in rice.

    PubMed

    ZhiMing, Yu; Bo, Kang; XiaoWei, He; ShaoLei, Lv; YouHuang, Bai; WoNa, Ding; Ming, Chen; Hyung-Taeg, Cho; Ping, Wu

    2011-06-01

    Root hair growth requires intensive cell-wall modification. This study demonstrates that root hair-specific expansin As, a sub-clade of the cell wall-loosening expansin proteins, are required for root hair elongation in rice (Oryza sativa L.). We identified a gene encoding EXPA17 (OsEXPA17) from a rice mutant with short root hairs. Promoter::reporter transgenic lines exhibited exclusive OsEXPA17 expression in root hair cells. The OsEXPA17 mutant protein (OsexpA17) contained a point mutation, causing a change in the amino acid sequence (Gly104→Arg). This amino acid alteration is predicted to disrupt a highly conserved disulfide bond in the mutant. Suppression of OsEXPA17 by RNA interference further confirmed requirement for the gene in root hair elongation. Complementation of the OsEXPA17 mutant with other root hair EXPAs (OsEXPA30 and Arabidopsis EXPA7) can restore root hair elongation, indicating functional conservation of these root hair EXPAs in monocots and dicots. These results demonstrate that members of the root hair EXPA sub-clade play a crucial role in root hair cell elongation in Graminaceae. PMID:21309868

  15. GLO-Roots: an imaging platform enabling multidimensional characterization of soil-grown root systems

    PubMed Central

    Rellán-Álvarez, Rubén; Lobet, Guillaume; Lindner, Heike; Pradier, Pierre-Luc; Sebastian, Jose; Yee, Muh-Ching; Geng, Yu; Trontin, Charlotte; LaRue, Therese; Schrager-Lavelle, Amanda; Haney, Cara H; Nieu, Rita; Maloof, Julin; Vogel, John P; Dinneny, José R

    2015-01-01

    Root systems develop different root types that individually sense cues from their local environment and integrate this information with systemic signals. This complex multi-dimensional amalgam of inputs enables continuous adjustment of root growth rates, direction, and metabolic activity that define a dynamic physical network. Current methods for analyzing root biology balance physiological relevance with imaging capability. To bridge this divide, we developed an integrated-imaging system called Growth and Luminescence Observatory for Roots (GLO-Roots) that uses luminescence-based reporters to enable studies of root architecture and gene expression patterns in soil-grown, light-shielded roots. We have developed image analysis algorithms that allow the spatial integration of soil properties, gene expression, and root system architecture traits. We propose GLO-Roots as a system that has great utility in presenting environmental stimuli to roots in ways that evoke natural adaptive responses and in providing tools for studying the multi-dimensional nature of such processes. DOI: http://dx.doi.org/10.7554/eLife.07597.001 PMID:26287479

  16. Resistance to compression of weakened roots subjected to different root reconstruction protocols

    PubMed Central

    ZOGHEIB, Lucas Villaça; SAAVEDRA, Guilherme de Siqueira Ferreira Anzaloni; CARDOSO, Paula Elaine; VALERA, Márcia Carneiro; de ARAÚJO, Maria Amélia Máximo

    2011-01-01

    Objective This study evaluated, in vitro, the fracture resistance of human non-vital teeth restored with different reconstruction protocols. Material and methods Forty human anterior roots of similar shape and dimensions were assigned to four groups (n=10), according to the root reconstruction protocol: Group I (control): non-weakened roots with glass fiber post; Group II: roots with composite resin by incremental technique and glass fiber post; Group III: roots with accessory glass fiber posts and glass fiber post; and Group IV: roots with anatomic glass fiber post technique. Following post cementation and core reconstruction, the roots were embedded in chemically activated acrylic resin and submitted to fracture resistance testing, with a compressive load at an angle of 45º in relation to the long axis of the root at a speed of 0.5 mm/min until fracture. All data were statistically analyzed with bilateral Dunnett's test (α=0.05). Results Group I presented higher mean values of fracture resistance when compared with the three experimental groups, which, in turn, presented similar resistance to fracture among each other. None of the techniques of root reconstruction with intraradicular posts improved root strength, and the incremental technique was suggested as being the most recommendable, since the type of fracture that occurred allowed the remaining dental structure to be repaired. Conclusion The results of this in vitro study suggest that the healthy remaining radicular dentin is more important to increase fracture resistance than the root reconstruction protocol. PMID:22231002

  17. Root cap influences root colonisation by Pseudomonas fluorescens SBW25 on maize.

    PubMed

    Humphris, Sonia N; Bengough, A Glyn; Griffiths, Bryan S; Kilham, Ken; Rodger, Sheena; Stubbs, Vicky; Valentine, Tracy A; Young, Iain M

    2005-09-01

    We investigated the influence of root border cells on the colonisation of seedling Zea mays roots by Pseudomonas fluorescens SBW25 in sandy loam soil packed at two dry bulk densities. Numbers of colony forming units (CFU) were counted on sequential sections of root for intact and decapped inoculated roots grown in loose (1.0 mg m(-3)) and compacted (1.3 mg m(-3)) soil. After two days of root growth, the numbers of P. fluorescens (CFU cm(-1)) were highest on the section of root just below the seed with progressively fewer bacteria near the tip, irrespective of density. The decapped roots had significantly more colonies of P. fluorescens at the tip compared with the intact roots: approximately 100-fold more in the loose and 30-fold more in the compact soil. In addition, confocal images of the root tips grown in agar showed that P. fluorescens could only be detected on the tips of the decapped roots. These results indicated that border cells, and their associated mucilage, prevented complete colonization of the root tip by the biocontrol agent P. fluorescens, possibly by acting as a disposable surface or sheath around the cap. PMID:16329978

  18. Lateral root initiation in Marsilea quadrifolia. I. Origin and histogensis of lateral roots

    NASA Technical Reports Server (NTRS)

    Lin, B. L.; Raghavan, V.

    1991-01-01

    In Marsilea quadrifolia, lateral roots arise from modified single cells of the endodermis located opposite the protoxylem poles within the meristematic region of the parent root. The initial cell divides in four specific planes to establish a five-celled lateral root primordium, with a tetrahedral apical cell in the centre and the oldest merophytes and the root cap along the sides. The cells of the merophyte divide in a precise pattern to give rise to the cells of the cortex, endodermis, pericycle, and vascular tissues of the emerging lateral root. Although the construction of the parent root is more complicated than that of lateral roots, patterns of cell division and tissue formation are similar in both types of roots, with the various tissues being arranged in similar positions in relation to the central axis. Vascular connection between the lateral root primordium and the parent root is derived from the pericycle cells lying between the former and the protoxylem members of the latter. It is proposed that the central axis of the root is not only a geometric centre, but also a physiological centre which determines the fate of the different cell types.

  19. Root phenology at Harvard Forest and beyond

    NASA Astrophysics Data System (ADS)

    Abramoff, R. Z.; Finzi, A.

    2013-12-01

    Roots are hidden from view and heterogeneously distributed making them difficult to study in situ. As a result, the causes and timing of root production are not well understood. Researchers have long assumed that above and belowground phenology is synchronous; for example, most parameterizations of belowground carbon allocation in terrestrial biosphere models are based on allometry and represent a fixed fraction of net C uptake. However, using results from metaanalysis as well as empirical data from oak and hemlock stands at Harvard Forest, we show that synchronous root and shoot growth is the exception rather than the rule. We collected root and shoot phenology measurements from studies across four biomes (boreal, temperate, Mediterranean, and subtropical). General patterns of root phenology varied widely with 1-5 production peaks in a growing season. Surprisingly, in 9 out of the 15 studies, the first root production peak was not the largest peak. In the majority of cases maximum shoot production occurred before root production (Offset>0 in 32 out of 47 plant sample means). The number of days offset between maximum root and shoot growth was negatively correlated with median annual temperature and therefore differs significantly across biomes (ANOVA, F3,43=9.47, p<0.0001). This decline in offset with increasing temperature may reflect greater year-round coupling between air and soil temperature in warm biomes. Growth form (woody or herbaceous) also influenced the relative timing of root and shoot growth. Woody plants had a larger range of days between root and shoot growth peaks as well as a greater number of growth peaks. To explore the range of phenological relationships within woody plants in the temperate biome, we focused on above and belowground phenology in two common northeastern tree species, Quercus rubra and Tsuga canadensis. Greenness index, rate of stem growth, root production and nonstructural carbohydrate content were measured beginning in April

  20. Variation of the Linkage of Root Function with Root Branch Order

    PubMed Central

    Chen, Zhengxia; Zeng, Hui

    2013-01-01

    Mounting evidence has shown strong linkage of root function with root branch order. However, it is not known whether this linkage is consistent in different species. Here, root anatomic traits of the first five branch order were examined in five species differing in plant phylogeny and growth form in tropical and subtropical forests of south China. In Paramichelia baillonii, one tree species in Magnoliaceae, the intact cortex as well as mycorrhizal colonization existed even in the fifth-order root suggesting the preservation of absorption function in the higher-order roots. In contrast, dramatic decreases of cortex thickness and mycorrhizal colonization were observed from lower- to higher-order roots in three other tree species, Cunninghamia lanceolata, Acacia auriculiformis and Gordonia axillaries, which indicate the loss of absorption function. In a fern, Dicranopteris dichotoma, there were several cortex layers with prominently thickened cell wall and no mycorrhizal colonization in the third- and fourth-order roots, also demonstrating the loss of absorptive function in higher-order roots. Cluster analysis using these anatomic traits showed a different classification of root branch order in P. baillonii from other four species. As for the conduit diameter-density relationship in higher-order roots, the mechanism underpinning this relationship in P. baillonii was different from that in other species. In lower-order roots, different patterns of coefficient of variance for conduit diameter and density provided further evidence for the two types of linkage of root function with root branch order. These linkages corresponding to two types of ephemeral root modules have important implication in the prediction of terrestrial carbon cycling, although we caution that this study was pseudo-replicated. Future studies by sampling more species can test the generality of these two types of linkage. PMID:23451168

  1. Do ectomycorrhizal and arbuscular mycorrhizal temperate tree species systematically differ in root order-related fine root morphology and biomass?

    PubMed Central

    Kubisch, Petra; Hertel, Dietrich; Leuschner, Christoph

    2015-01-01

    While most temperate broad-leaved tree species form ectomycorrhizal (EM) symbioses, a few species have arbuscular mycorrhizas (AM). It is not known whether EM and AM tree species differ systematically with respect to fine root morphology, fine root system size and root functioning. In a species-rich temperate mixed forest, we studied the fine root morphology and biomass of three EM and three AM tree species from the genera Acer, Carpinus, Fagus, Fraxinus, and Tilia searching for principal differences between EM and AM trees. We further assessed the evidence of convergence or divergence in root traits among the six co-occurring species. Eight fine root morphological and chemical traits were investigated in root segments of the first to fourth root order in three different soil depths and the relative importance of the factors root order, tree species and soil depth for root morphology was determined. Root order was more influential than tree species while soil depth had only a small effect on root morphology All six species showed similar decreases in specific root length and specific root area from the 1st to the 4th root order, while the species patterns differed considerably in root tissue density, root N concentration, and particularly with respect to root tip abundance. Most root morphological traits were not significantly different between EM and AM species (except for specific root area that was larger in AM species), indicating that mycorrhiza type is not a key factor influencing fine root morphology in these species. The order-based root analysis detected species differences more clearly than the simple analysis of bulked fine root mass. Despite convergence in important root traits among AM and EM species, even congeneric species may differ in certain fine root morphological traits. This suggests that, in general, species identity has a larger influence on fine root morphology than mycorrhiza type. PMID:25717334

  2. Scalable encryption using alpha rooting

    NASA Astrophysics Data System (ADS)

    Wharton, Eric J.; Panetta, Karen A.; Agaian, Sos S.

    2008-04-01

    Full and partial encryption methods are important for subscription based content providers, such as internet and cable TV pay channels. Providers need to be able to protect their products while at the same time being able to provide demonstrations to attract new customers without giving away the full value of the content. If an algorithm were introduced which could provide any level of full or partial encryption in a fast and cost effective manner, the applications to real-time commercial implementation would be numerous. In this paper, we present a novel application of alpha rooting, using it to achieve fast and straightforward scalable encryption with a single algorithm. We further present use of the measure of enhancement, the Logarithmic AME, to select optimal parameters for the partial encryption. When parameters are selected using the measure, the output image achieves a balance between protecting the important data in the image while still containing a good overall representation of the image. We will show results for this encryption method on a number of images, using histograms to evaluate the effectiveness of the encryption.

  3. Ecology of Root Colonizing Massilia (Oxalobacteraceae)

    PubMed Central

    Ofek, Maya; Hadar, Yitzhak; Minz, Dror

    2012-01-01

    Background Ecologically meaningful classification of bacterial populations is essential for understanding the structure and function of bacterial communities. As in soils, the ecological strategy of the majority of root-colonizing bacteria is mostly unknown. Among those are Massilia (Oxalobacteraceae), a major group of rhizosphere and root colonizing bacteria of many plant species. Methodology/Principal Findings The ecology of Massilia was explored in cucumber root and seed, and compared to that of Agrobacterium population, using culture-independent tools, including DNA-based pyrosequencing, fluorescence in situ hybridization and quantitative real-time PCR. Seed- and root-colonizing Massilia were primarily affiliated with other members of the genus described in soil and rhizosphere. Massilia colonized and proliferated on the seed coat, radicle, roots, and also on hyphae of phytopathogenic Pythium aphanidermatum infecting seeds. High variation in Massilia abundance was found in relation to plant developmental stage, along with sensitivity to plant growth medium modification (amendment with organic matter) and potential competitors. Massilia absolute abundance and relative abundance (dominance) were positively related, and peaked (up to 85%) at early stages of succession of the root microbiome. In comparison, variation in abundance of Agrobacterium was moderate and their dominance increased at later stages of succession. Conclusions In accordance with contemporary models for microbial ecology classification, copiotrophic and competition-sensitive root colonization by Massilia is suggested. These bacteria exploit, in a transient way, a window of opportunity within the succession of communities within this niche. PMID:22808103

  4. How to bond to root canal dentin

    NASA Astrophysics Data System (ADS)

    Nica, Luminita; Todea, Carmen; Furtos, Gabriel; Baldea, Bogdan

    2014-01-01

    Bonding to root canal dentin may be difficult due to various factors: the structural characteristic of the root canal dentin, which is different from that of the coronal dentin; the presence of the organic tissue of the dental pulp inside the root canal, which has to be removed during the cleaning-shaping of the root canal system; the smear-layer resulted after mechanical instrumentation, which may interfere with the adhesion of the filling materials; the type of the irrigants used in the cleaning protocol; the type of the sealer and core material used in the obturation of the endodontic space; the type of the materials used for the restoration of the endodontically treated teeth. The influence of the cleaning protocol, of the root canal filling material, of the type of the adhesive system used in the restoration of the treated teeth and of the region of the root canal, on the adhesion of several filling and restorative materials to root canal dentin was evaluated in the push-out bond strength test on 1-mm thick slices of endodontically treated human teeth. The results showed that all these factors have a statistically significant influence on the push-out bond strength. Formation of resin tags between radicular dentin and the investigated materials was observed in some of the samples at SEM analysis.

  5. 13. PHOTOCOPY OF ILLUSTRATED CIRCULAR OF 'ROOTS NEW IRON POSITIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. PHOTOCOPY OF ILLUSTRATED CIRCULAR OF 'ROOTS NEW IRON POSITIVE BLAST BLOWER,' CA. JAN. 1880, FROM FILES OF ROOTS-CONNERSVILLE BLOWER CO., CONNERSVILLE, IND. - P. H. & F. M. Roots Company, Eastern Avenue, Connersville, Fayette County, IN

  6. Bitter Root Irrigation district canal, looking east, typical section (canal ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Bitter Root Irrigation district canal, looking east, typical section (canal full) - Bitter Root Irrigation Project, Bitter Root Irrigation Canal, Heading at Rock Creek Diversion Dam, West of U.S. Highway 93, Darby, Ravalli County, MT

  7. Bitter Root Irrigation district canal, looking east, typical section and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Bitter Root Irrigation district canal, looking east, typical section and crossing - Bitter Root Irrigation Project, Bitter Root Irrigation Canal, Heading at Rock Creek Diversion Dam, West of U.S. Highway 93, Darby, Ravalli County, MT

  8. 10. PHOTOCOPY OF 'P. H. & F. M. ROOTS FOUNDARY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. PHOTOCOPY OF 'P. H. & F. M. ROOTS FOUNDARY MANUFACTURERS OF ROOTS BLOWERS' FROM INDIANAPOLIS STAR, June 13, 1926, Gravure Section, p. 2 - P. H. & F. M. Roots Company, Eastern Avenue, Connersville, Fayette County, IN

  9. Bidirectional recovery patterns of Mojave Desert vegetation in an aqueduct pipeline corridor after 36 years: I. Perennial shrubs and grasses

    USGS Publications Warehouse

    Berry, Kristin H.; Weigand, James F.; Gowan, Timothy A.; Mack, Jeremy S.

    2015-01-01

    We studied recovery of 21 perennial plant species along a severely disturbed aqueduct corridor in a Larrea tridentata-Ambrosia dumosa plant alliance in the Mojave Desert 36 years after construction. The 97-m wide corridor contained a central dirt road and buried aqueduct pipeline. We established transects at 0 m (road verge), 20 m and 40 m into the disturbance corridor, and at 100 m in undisturbed habitat (the control). Although total numbers of shrubs per transect did not vary significantly with distance from the verge, canopy cover of shrubs, species richness, and species diversity were higher in the control than at the verge and other distances. Canopy cover of common shrubs (Ericameria nauseosa, Ambrosia salsola, A. dumosa, L. tridentata, Grayia spinosa) and perennial grasses (Elymus elymoides, Poa secunda) also varied significantly by location. Discriminant analysis clearly separated the four distances based on plant composition. Patterns of recovery were bidirectional: secondary succession from the control into the disturbance corridor and inhibition from the verge in the direction of the control. Time estimated for species composition to resemble the control is dependent on location within the disturbance corridor and could be centuries at the road verge. Our findings have applications to other deserts.

  10. A thermodynamic formulation of root water uptake

    NASA Astrophysics Data System (ADS)

    Hildebrandt, A.; Kleidon, A.; Bechmann, M.

    2015-12-01

    By extracting bound water from the soil and lifting it to the canopy, root systems of vegetation perform work. Here we describe how the energetics involved in root water uptake can be quantified. The illustration is done using a simple, four-box model of the soil-root system to represent heterogeneity and a parameterization in which root water uptake is driven by the xylem potential of the plant with a fixed flux boundary condition. We use this approach to evaluate the effects of soil moisture heterogeneity and root system properties on the dissipative losses and export of energy involved in root water uptake. For this, we derive an expression that relates the energy export at the root collar to a sum of terms that reflect all fluxes and storage changes along the flow path in thermodynamic terms. We conclude that such a thermodynamic evaluation of root water uptake conveniently provides insights into the impediments of different processes along the entire flow path and explicitly accounting not only for the resistances along the flow path and those imposed by soil drying but especially the role of heterogenous soil water distribution. The results show that least energy needs to be exported and dissipative losses are minimized by a root system if it extracts water uniformly from the soil. This has implications for plant water relations in forests where canopies generate heterogenous input patterns. Our diagnostic in the energy domain should be useful in future model applications for quantifying how plants can evolve towards greater efficiency in their structure and function, particularly in heterogenous soil environments. Generally, this approach may help to better describe heterogeneous processes in the soil in a simple, yet physically-based way.

  11. Root type matters: measurements of water uptake by seminal, crown and lateral roots of maize

    NASA Astrophysics Data System (ADS)

    Ahmed, Mutez Ali; Zarebanadkouki, Mohsen; Kaestner, Anders; Carminati, Andrea

    2016-04-01

    Roots play a key role in water acquisition and are a significant component of plant adaptation to different environmental conditions. Although maize (Zea mays L.) is one of the most important crops worldwide, there is limited information on the function of different root segments and types in extracting water from soils. Aim of this study was to investigate the location of root water uptake in mature maize. We used neutron radiography to image the spatial distribution of maize roots and trace the transport of injected deuterated water (D2O) in soil and roots. Maize plants were grown in aluminum containers filled with a sandy soil that was kept homogeneously wet throughout the experiment. When the plants were five weeks-old, we injected D2O into selected soil regions. The transport of D2O was simulated using a diffusion-convection numerical model. By fitting the observed D2O transport we quantified the diffusion coefficient and the water uptake of the different root segments. The model was initially developed and tested with two weeks-old maize (Ahmed et. al. 2015), for which we found that water was mainly taken up by lateral roots and the water uptake of the seminal roots was negligible. Here, we used this method to measure root water uptake in a mature maize root system. The root architecture of five weeks-old maize consisted of primary and seminal roots with long laterals and crown (nodal) roots that emerged from the above ground part of the plant two weeks after planting. The crown roots were thicker than the seminal roots and had fewer and shorter laterals. Surprisingly, we found that the water was mainly taken up by the crown roots and their laterals, while the lateral roots of seminal roots, which were the main location of water uptake of younger plants, stopped to take up water. Interestingly, we also found that in contrast to the seminal roots, the crown roots were able to take up water also from their distal segments. We conclude that for the two weeks

  12. Adventitious root induction in Arabidopsis thaliana as a model for in vitro root organogenesis.

    PubMed

    Verstraeten, Inge; Beeckman, Tom; Geelen, Danny

    2013-01-01

    Adventitious root formation, the development of roots on non-root tissue (e.g. leaves, hypocotyls and stems) is a critical step during micropropagation. Although root induction treatments are routinely used for a large number of species micropropagated in vitro as well as for in vivo cuttings, the mechanisms controlling adventitious rooting are still poorly understood. Researchers attempt to gain better insight into the molecular aspects by studying adventitious rooting in Arabidopsis thaliana. The existing assay involves etiolation of seedlings and measurements of de novo formed roots on the elongated hypocotyl. The etiolated hypocotyls express a novel auxin-controlled signal transduction pathway in which auxin response factors (ARFs), microRNAs and environmental conditions that drive adventitious rooting are integrated. An alternative assay makes use of so-called thin cell layers (TCL), excised strips of cells from the inflorescence stem of Arabidopsis thaliana. However, both the etiolated seedling system and the TCL assay are only distantly related to industrial rooting processes in which roots are induced on adult stem tissue. Here, we describe an adventitious root induction system that uses segments of the inflorescence stems of Arabidopsis thaliana, which have a histological structure similar to cuttings or in vitro micropropagated shoots. The system allows multiple treatments with chemicals as well as the evaluation of different environmental conditions on a large number of explants. It is therefore suitable for high throughput chemical screenings and experiments that require numerous data points for statistical analysis. Using this assay, the adventitious root induction capacity of classical auxins was evaluated and a differential response to the different auxins could be demonstrated. NAA, IBA and IAA stimulated adventitious rooting on the stem segment, whereas 2,4-D and picloram did not. Light conditions profoundly influenced the root induction capacity

  13. Clinical technique for invasive cervical root resorption

    PubMed Central

    Silveira, Luiz Fernando Machado; Silveira, Carina Folgearini; Martos, Josué; Piovesan, Edno Moacir; César Neto, João Batista

    2011-01-01

    This clinical case report describes the diagnosis and treatment of an external invasive cervical resorption. A 17-year-old female patient had a confirmed diagnosis of invasive cervical resorption class 4 by cone beam computerized tomography. Although, there was no communication with the root canal, the invasive resorption process was extending into the cervical and middle third of the root. The treatment of the cervical resorption of the lateral incisor interrupted the resorptive process and restored the damaged root surface and the dental functions without any esthetic sequelae. Both the radiographic examination and computed tomography are imperative to reveal the extent of the defect in the differential diagnosis. PMID:22144822

  14. Complex root networks of Chinese characters

    NASA Astrophysics Data System (ADS)

    Lee, Po-Han; Chen, Jia-Ling; Wang, Po-Cheng; Chi, Ting-Ting; Xiao, Zhi-Ren; Jhang, Zih-Jian; Yeh, Yeong-Nan; Chen, Yih-Yuh; Hu, Chin-Kun

    There are several sets of Chinese characters still available today, including Oracle Bone Inscriptions (OBI) in Shang Dynasty, Chu characters (CC) used in Chu of Warring State Period, Small Seal Script in dictionary Shuowen Jiezi (SJ) in Eastern Han Dynasty, and Kangxi Dictionary (KD) in Qing Dynasty. Such as Chinese characters were all constructed via combinations of meaningful patterns, called roots. Our studies for the complex networks of all roots indicate that the roots of the characters in OBI, CC, SJ and KD have characteristics of small world networks and scale-free networks.

  15. THttpServer class in ROOT

    NASA Astrophysics Data System (ADS)

    Adamczewski-Musch, Joern; Linev, Sergey

    2015-12-01

    The new THttpServer class in ROOT implements HTTP server for arbitrary ROOT applications. It is based on Civetweb embeddable HTTP server and provides direct access to all objects registered for the server. Objects data could be provided in different formats: binary, XML, GIF/PNG, and JSON. A generic user interface for THttpServer has been implemented with HTML/JavaScript based on JavaScript ROOT development. With any modern web browser one could list, display, and monitor objects available on the server. THttpServer is used in Go4 framework to provide HTTP interface to the online analysis.

  16. BOREAS TE-2 Root Respiration Data

    NASA Technical Reports Server (NTRS)

    Ryan, Michael G.; Lavigne, Michael; Hall, Forrest G. (Editor); Papagno, Andrea (Editor)

    2000-01-01

    The BOREAS TE-2 team collected several data sets in support of its efforts to characterize and interpret information on the respiration of the foliage, roots, and wood of boreal vegetation. This data set includes means of tree root respiration measurements on roots having diameters ranging from 0 to 2 mm conducted in the NSA during the growing season of 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  17. Getting to the roots of it: Genetic and hormonal control of root architecture.

    PubMed

    Jung, Janelle K H; McCouch, Susan

    2013-01-01

    Root system architecture (RSA) - the spatial configuration of a root system - is an important developmental and agronomic trait, with implications for overall plant architecture, growth rate and yield, abiotic stress resistance, nutrient uptake, and developmental plasticity in response to environmental changes. Root architecture is modulated by intrinsic, hormone-mediated pathways, intersecting with pathways that perceive and respond to external, environmental signals. The recent development of several non-invasive 2D and 3D root imaging systems has enhanced our ability to accurately observe and quantify architectural traits on complex whole-root systems. Coupled with the powerful marker-based genotyping and sequencing platforms currently available, these root phenotyping technologies lend themselves to large-scale genome-wide association studies, and can speed the identification and characterization of the genes and pathways involved in root system development. This capability provides the foundation for examining the contribution of root architectural traits to the performance of crop varieties in diverse environments. This review focuses on our current understanding of the genes and pathways involved in determining RSA in response to both intrinsic and extrinsic (environmental) response pathways, and provides a brief overview of the latest root system phenotyping technologies and their potential impact on elucidating the genetic control of root development in plants. PMID:23785372

  18. Light as stress factor to plant roots – case of root halotropism

    PubMed Central

    Yokawa, Ken; Fasano, Rossella; Kagenishi, Tomoko; Baluška, František

    2014-01-01

    Despite growing underground, largely in darkness, roots emerge to be very sensitive to light. Recently, several important papers have been published which reveal that plant roots not only express all known light receptors but also that their growth, physiology and adaptive stress responses are light-sensitive. In Arabidopsis, illumination of roots speeds-up root growth via reactive oxygen species-mediated and F-actin dependent process. On the other hand, keeping Arabidopsis roots in darkness alters F-actin distribution, polar localization of PIN proteins as well as polar transport of auxin. Several signaling components activated by phytohormones are overlapping with light-related signaling cascade. We demonstrated that the sensitivity of roots to salinity is altered in the light-grown Arabidopsis roots. Particularly, light-exposed roots are less effective in their salt-avoidance behavior known as root halotropism. Here we discuss these new aspects of light-mediated root behavior from cellular, physiological and evolutionary perspectives. PMID:25566292

  19. Getting to the roots of it: Genetic and hormonal control of root architecture

    PubMed Central

    Jung, Janelle K. H.; McCouch, Susan

    2013-01-01

    Root system architecture (RSA) – the spatial configuration of a root system – is an important developmental and agronomic trait, with implications for overall plant architecture, growth rate and yield, abiotic stress resistance, nutrient uptake, and developmental plasticity in response to environmental changes. Root architecture is modulated by intrinsic, hormone-mediated pathways, intersecting with pathways that perceive and respond to external, environmental signals. The recent development of several non-invasive 2D and 3D root imaging systems has enhanced our ability to accurately observe and quantify architectural traits on complex whole-root systems. Coupled with the powerful marker-based genotyping and sequencing platforms currently available, these root phenotyping technologies lend themselves to large-scale genome-wide association studies, and can speed the identification and characterization of the genes and pathways involved in root system development. This capability provides the foundation for examining the contribution of root architectural traits to the performance of crop varieties in diverse environments. This review focuses on our current understanding of the genes and pathways involved in determining RSA in response to both intrinsic and extrinsic (environmental) response pathways, and provides a brief overview of the latest root system phenotyping technologies and their potential impact on elucidating the genetic control of root development in plants. PMID:23785372

  20. Arthroscopic Repair of Posterior Meniscal Root Tears

    PubMed Central

    Matheny, Lauren; Moulton, Samuel G.; Dean, Chase S.; LaPrade, Robert F.

    2016-01-01

    Objectives: The purpose of this study was to compare subjective clinical outcomes in patients requiring arthroscopic transtibial pullout repair for posterior meniscus root tears of the medial and lateral menisci. We hypothesized that improvement in function and activity level would be similar among patients undergoing lateral and medial meniscal root repairs. Methods: This study was IRB approved. All patients who underwent posterior meniscal root repair by a single orthopaedic surgeon were included in this study. Detailed operative data were documented at surgery. Patients completed a subjective questionnaire, including Lysholm score, Tegner activity scale, WOMAC, SF-12 and patient satisfaction with outcome, which were collected preoperatively and at a minimum of two years postoperatively. Failure was defined as any patient who underwent revision meniscal root repair or partial meniscectomy following the index surgery. Results: There were 50 patients (16 females, 34 males) with a mean age of 37.8 years (range, 16.6-65.7) and a mean BMI of 27.3 (range, 20.5-49.2) included in this study. Fifteen patients underwent lateral meniscus root repair and 35 patients underwent medial meniscus root repair. Three patients who underwent lateral meniscus root repair required revision meniscus root repair surgery, while no patients who underwent medial meniscus root repair required revision surgery (p=0.26). There was a significant difference in preoperative and postoperative Lysholm score (53 vs. 78) (p<0.001), Tegner activity scale (2.0 vs. 4.0) (p=0.03), SF-12 physical component subscale (38 vs. 50) (p=0.001) and WOMAC (36 vs. 8) (p<0.001) for the total population. Median patient satisfaction with outcome was 9 (range, 1-10). There was no significant difference in mean age between lateral and medial root repair groups (32 vs. 40) (p=0.12) or gender (p=0.19). There was no significant difference in gender between lateral and medial root repair groups (p=0.95). There was a

  1. RootScape: a landmark-based system for rapid screening of root architecture in Arabidopsis.

    PubMed

    Ristova, Daniela; Rosas, Ulises; Krouk, Gabriel; Ruffel, Sandrine; Birnbaum, Kenneth D; Coruzzi, Gloria M

    2013-03-01

    The architecture of plant roots affects essential functions including nutrient and water uptake, soil anchorage, and symbiotic interactions. Root architecture comprises many features that arise from the growth of the primary and lateral roots. These root features are dictated by the genetic background but are also highly responsive to the environment. Thus, root system architecture (RSA) represents an important and complex trait that is highly variable, affected by genotype × environment interactions, and relevant to survival/performance. Quantification of RSA in Arabidopsis (Arabidopsis thaliana) using plate-based tissue culture is a very common and relatively rapid assay, but quantifying RSA represents an experimental bottleneck when it comes to medium- or high-throughput approaches used in mutant or genotype screens. Here, we present RootScape, a landmark-based allometric method for rapid phenotyping of RSA using Arabidopsis as a case study. Using the software AAMToolbox, we created a 20-point landmark model that captures RSA as one integrated trait and used this model to quantify changes in the RSA of Arabidopsis (Columbia) wild-type plants grown under different hormone treatments. Principal component analysis was used to compare RootScape with conventional methods designed to measure root architecture. This analysis showed that RootScape efficiently captured nearly all the variation in root architecture detected by measuring individual root traits and is 5 to 10 times faster than conventional scoring. We validated RootScape by quantifying the plasticity of RSA in several mutant lines affected in hormone signaling. The RootScape analysis recapitulated previous results that described complex phenotypes in the mutants and identified novel gene × environment interactions. PMID:23335624

  2. Allometry of root branching and its relationship to root morphological and functional traits in three range grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several studies have documented the existence of correlative mechanisms that control lateral root emergence in plants. To better understand root branching responses to nutrients, root growth in three range grasses [Whitmar cultivar of bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) Love), Hyc...

  3. Rooting depths of plants relative to biological and environmental factors

    SciTech Connect

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

    1984-11-01

    In 1981 to 1982 an extensive bibliographic study was completed to document rooting depths of native plants in the United States. The data base presently contains 1034 citations with approximately 12,000 data elements. In this paper the data were analyzed for rooting depths as related to life form, soil type, geographical region, root type, family, root depth to shoot height ratios, and root depth to root lateral ratios. Average rooting depth and rooting frequencies were determined and related to present low-level waste site maintenance.

  4. Understanding plant root system influences on soil strength and stability

    NASA Astrophysics Data System (ADS)

    Bengough, A. Glyn; Brown, Jennifer L.; Loades, Kenneth W.; Knappett, Jonathan A.; Meijer, Gertjan; Nicoll, Bruce

    2016-04-01

    Keywords: root growth, soil reinforcement, tensile strength Plant roots modify and reinforce the soil matrix, stabilising it against erosion and shallow landslides. Roots mechanically bind the soil particles together and modify the soil hydrology via water uptake, creation of biopores, and modification of the soil water-release characteristic. Key to understanding the mechanical reinforcement of soil by roots is the relation between root strength and root diameter measured for roots in any given soil horizon. Thin roots have frequently been measured to have a greater tensile strength than thick roots, but their strength is also often much more variable. We consider the factors influencing this strength-diameter relationship, considering relations between root tensile strength and root dry density, root water content, root age, and root turnover in several woody and non-woody species. The role of possible experimental artefacts and measurement techniques will be considered. Tensile strength increased generally with root age and decreased with thermal time after excision as a result of root decomposition. Single factors alone do not appear to explain the strength-diameter relationship, and both strength/stiffness and dry density may vary between different layers of tissue within a single root. Results will be discussed to consider how we can achieve a more comprehensive understanding of the variation in root biomechanical properties, and its consequences for soil reinforcement. Acknowledgements: The James Hutton Institute receives funding from the Scottish Government. AGB and JAK acknowledge part funding from EPSRC (EP/M020355/1).

  5. Root gravitropism in maize and Arabidopsis

    NASA Technical Reports Server (NTRS)

    Evans, Michael L.

    1993-01-01

    Research during the period 1 March 1992 to 30 November 1993 focused on improvements in a video digitizer system designed to automate the recording of surface extension in plants responding to gravistimulation. The improvements included modification of software to allow detailed analysis of localized extension patterns in roots of Arabidopsis. We used the system to analyze the role of the postmitotic isodiametric growth zone (a region between the meristem and the elongation zone) in the response of maize roots to auxin, calcium, touch and gravity. We also used the system to analyze short-term auxin and gravitropic responses in mutants of Arabidopsis with reduced auxin sensitivity. In a related project, we studied the relationship between growth rate and surface electrical currents in roots by examining the effects of gravity and thigmostimulation on surface potentials in maize roots.

  6. DMA thermal analysis of yacon tuberous roots

    NASA Astrophysics Data System (ADS)

    Blahovec, J.; Lahodová, M.; Kindl, M.; Fernández, E. C.

    2013-12-01

    Specimens prepared from yacon roots in first two weeks after harvest were tested by dynamic mechanical analysis thermal analysis at temperatures between 30 and 90°C. No differences between different parts of roots were proved. There were indicated some differences in the test parameters that were caused by short time storage of the roots. One source of the differences was loss of water during the roots storage. The measured modulus increased during short time storage. Detailed study of changes of the modulus during the specimen dynamic mechanical analysis test provided information about different development of the storage and loss moduli during the specimen heating. The observed results can be caused by changes in cellular membranes observed earlier during vegetable heating, and by composition changes due to less stable components of yacon like inulin.

  7. "Roots" Touched Children: Planned or Not

    ERIC Educational Resources Information Center

    Greathouse, Betty

    1977-01-01

    Explores children's reactions to the televised version of Alex Haley's "Roots" through interviews with thirty 8-year-old third-graders (10 Black, 10 Mexican-American, 10 White) from two classrooms in South Phoenix, Arizona. (BF/JH)

  8. Irregular sesquiterpenoids from Ligusticum grayi roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Root oil of Ligusticum grayi (Apiaceae) contains numerous irregular sesquiterpenoids. In addition to the known acyclic sesquilavandulol and a new sesquilavandulyl aldehyde, two thapsanes, one epithapsane, and fourteen sesquiterpenoids representing eight novel carbon skeletons were found. The new sk...

  9. Mapping gene activity of Arabidopsis root hairs

    PubMed Central

    2013-01-01

    Background Quantitative information on gene activity at single cell-type resolution is essential for the understanding of how cells work and interact. Root hairs, or trichoblasts, tubular-shaped outgrowths of specialized cells in the epidermis, represent an ideal model for cell fate acquisition and differentiation in plants. Results Here, we provide an atlas of gene and protein expression in Arabidopsis root hair cells, generated by paired-end RNA sequencing and LC/MS-MS analysis of protoplasts from plants containing a pEXP7-GFP reporter construct. In total, transcripts of 23,034 genes were detected in root hairs. High-resolution proteome analysis led to the reliable identification of 2,447 proteins, 129 of which were differentially expressed between root hairs and non-root hair tissue. Dissection of pre-mRNA splicing patterns showed that all types of alternative splicing were cell type-dependent, and less complex in EXP7-expressing cells when compared to non-root hair cells. Intron retention was repressed in several transcripts functionally related to root hair morphogenesis, indicative of a cell type-specific control of gene expression by alternative splicing of pre-mRNA. Concordance between mRNA and protein expression was generally high, but in many cases mRNA expression was not predictive for protein abundance. Conclusions The integrated analysis shows that gene activity in root hairs is dictated by orchestrated, multilayered regulatory mechanisms that allow for a cell type-specific composition of functional components. PMID:23800126

  10. Anatomical aspects of angiosperm root evolution

    PubMed Central

    Seago, James L.; Fernando, Danilo D.

    2013-01-01

    Background and Aims Anatomy had been one of the foundations in our understanding of plant evolutionary trends and, although recent evo-devo concepts are mostly based on molecular genetics, classical structural information remains useful as ever. Of the various plant organs, the roots have been the least studied, primarily because of the difficulty in obtaining materials, particularly from large woody species. Therefore, this review aims to provide an overview of the information that has accumulated on the anatomy of angiosperm roots and to present possible evolutionary trends between representatives of the major angiosperm clades. Scope This review covers an overview of the various aspects of the evolutionary origin of the root. The results and discussion focus on angiosperm root anatomy and evolution covering representatives from basal angiosperms, magnoliids, monocots and eudicots. We use information from the literature as well as new data from our own research. Key Findings The organization of the root apical meristem (RAM) of Nymphaeales allows for the ground meristem and protoderm to be derived from the same group of initials, similar to those of the monocots, whereas in Amborellales, magnoliids and eudicots, it is their protoderm and lateral rootcap which are derived from the same group of initials. Most members of Nymphaeales are similar to monocots in having ephemeral primary roots and so adventitious roots predominate, whereas Amborellales, Austrobaileyales, magnoliids and eudicots are generally characterized by having primary roots that give rise to a taproot system. Nymphaeales and monocots often have polyarch (heptarch or more) steles, whereas the rest of the basal angiosperms, magnoliids and eudicots usually have diarch to hexarch steles. Conclusions Angiosperms exhibit highly varied structural patterns in RAM organization; cortex, epidermis and rootcap origins; and stele patterns. Generally, however, Amborellales, magnoliids and, possibly

  11. Capillary-Effect Root-Environment System

    NASA Technical Reports Server (NTRS)

    Wright, Bruce D.

    1991-01-01

    Capillary-effect root-environment system (CERES) is experimental apparatus for growing plants in nutrient solutions. Solution circulated at slight tension in cavity filled with plastic screen and covered by porous plastic membrane. By adsorptive attraction, root draws solution through membrane. Conceived for use in microgravity of space, also finds terrestrial application in germinating seedlings, because it protects them from extremes of temperature, moisture, and soil pH and from overexposure to fertilizers and herbicides.

  12. [Apical root pins of high-karat gold alloys for resected roots].

    PubMed

    Handtmann, S; Lindemann, W; Sculte, W

    1989-02-01

    Following earlier studies on corrosion of silver pins in the root canal experience will be presented with the use of high-karat gold pins for apical closure of root amputations. The commercially available standardized Ackermann silver pins were replaced by high-karat gold pins of similar Vicker hardness and inserted in 218 patients with 264 root amputations since 1986. A clinical and radiological follow-up demonstrated a success rate of over 90%. PMID:2598876

  13. Lectin Binding to the Root and Root Hair Tips of the Tropical Legume Macroptilium atropurpureum Urb

    PubMed Central

    Ridge, R. W.; Rolfe, B. G.

    1986-01-01

    Ten fluorescein isothiocyanate-labeled lectins were tested on the roots of the tropical legume Macroptilium atropurpureum Urb. Four of these (concanavalin A, peanut agglutinin, Ricinis communis agglutinin I [RCA-I], wheat germ agglutinin) were found to bind to the exterior of root cap cells, the root cap slime, and the channels between epidermal cells in the root elongation zone. One of these lectins, RCA-I, bound to the root hair tips in the mature and emerging hair zones and also to sites at which root hairs were only just emerging. There was no RCA-I binding to immature trichoblasts. Preincubation of these lectins with their hapten sugars eliminated all types of root cell binding. By using a microinoculation technique, preincubation of the root surface with RCA-I lectin was found to inhibit infection and nodulation by Rhizobium spp. Preincubation of the root surface with the RCA-I hapten β-d-galactose or a mixture of RCA-I lectin and its hapten failed to inhibit nodulation. Application of RCA-I lectin to the root surface caused no apparent detrimental effects to the root hair cells and did not prevent the growth of root hairs. The lectin did not prevent Rhizobium sp. motility or viability even after 24 h of incubation. It was concluded that the RCA-I lectin-specific sugar β-d-galactose may be involved in the recognition or early infection stages, or both, in the Rhizobium sp. infection of M. atropurpureum. Images PMID:16346989

  14. ASTROCULTURE (TM) root metabolism and cytochemical analysis.

    PubMed

    Porterfield, D M; Barta, D J; Ming, D W; Morrow, R C; Musgrave, M E

    2000-01-01

    Physiology of the root system is dependent upon oxygen availability and tissue respiration. During hypoxia nutrient and water acquisition may be inhibited, thus affecting the overall biochemical and physiological status of the plant. For the Astroculture (TM) plant growth hardware, the availability of oxygen in the root zone was measured by examining the changes in alcohol dehydrogenase (ADH) activity within the root tissue. ADH activity is a sensitive biochemical indicator of hypoxic conditions in plants and was measured in both spaceflight and control roots. In addition to the biochemical enzyme assays, localization of ADH in the root tissue was examined cytochemically. The results of these analyses showed that ADH activity increased significantly as a result of spaceflight exposure. Enzyme activity increased 248% to 304% in dwarf wheat when compared with the ground controls and Brassica showed increases between 334% and 579% when compared with day zero controls. Cytochemical staining revealed no differences in ADH tissue localization in any of the dwarf wheat treatments. These results show the importance of considering root system oxygenation in designing and building nutrient delivery hardware for spaceflight plant cultivation and confirm previous reports of an ADH response associated with spaceflight exposure. PMID:11543169

  15. Vertical root fractures and their management

    PubMed Central

    Khasnis, Sandhya Anand; Kidiyoor, Krishnamurthy Haridas; Patil, Anand Basavaraj; Kenganal, Smita Basavaraj

    2014-01-01

    Vertical root fractures associated with endodontically treated teeth and less commonly in vital teeth represent one of the most difficult clinical problems to diagnose and treat. In as much as there are no specific symptoms, diagnosis can be difficult. Clinical detection of this condition by endodontists is becoming more frequent, where as it is rather underestimated by the general practitioners. Since, vertical root fractures almost exclusively involve endodontically treated teeth; it often becomes difficult to differentiate a tooth with this condition from an endodontically failed one or one with concomitant periodontal involvement. Also, a tooth diagnosed for vertical root fracture is usually extracted, though attempts to reunite fractured root have been done in various studies with varying success rates. Early detection of a fractured root and extraction of the tooth maintain the integrity of alveolar bone for placement of an implant. Cone beam computed tomography has been shown to be very accurate in this regard. This article focuses on the diagnostic and treatment strategies, and discusses about predisposing factors which can be useful in the prevention of vertical root fractures. PMID:24778502

  16. Gene expression regulation in roots under drought.

    PubMed

    Janiak, Agnieszka; Kwaśniewski, Mirosław; Szarejko, Iwona

    2016-02-01

    Stress signalling and regulatory networks controlling expression of target genes are the basis of plant response to drought. Roots are the first organs exposed to water deficiency in the soil and are the place of drought sensing. Signalling cascades transfer chemical signals toward the shoot and initiate molecular responses that lead to the biochemical and morphological changes that allow plants to be protected against water loss and to tolerate stress conditions. Here, we present an overview of signalling network and gene expression regulation pathways that are actively induced in roots under drought stress. In particular, the role of several transcription factor (TF) families, including DREB, AP2/ERF, NAC, bZIP, MYC, CAMTA, Alfin-like and Q-type ZFP, in the regulation of root response to drought are highlighted. The information provided includes available data on mutual interactions between these TFs together with their regulation by plant hormones and other signalling molecules. The most significant downstream target genes and molecular processes that are controlled by the regulatory factors are given. These data are also coupled with information about the influence of the described regulatory networks on root traits and root development which may translate to enhanced drought tolerance. This is the first literature survey demonstrating the gene expression regulatory machinery that is induced by drought stress, presented from the perspective of roots. PMID:26663562

  17. ASTROCULTURE (TM) root metabolism and cytochemical analysis

    NASA Technical Reports Server (NTRS)

    Porterfield, D. M.; Barta, D. J.; Ming, D. W.; Morrow, R. C.; Musgrave, M. E.

    2000-01-01

    Physiology of the root system is dependent upon oxygen availability and tissue respiration. During hypoxia nutrient and water acquisition may be inhibited, thus affecting the overall biochemical and physiological status of the plant. For the Astroculture (TM) plant growth hardware, the availability of oxygen in the root zone was measured by examining the changes in alcohol dehydrogenase (ADH) activity within the root tissue. ADH activity is a sensitive biochemical indicator of hypoxic conditions in plants and was measured in both spaceflight and control roots. In addition to the biochemical enzyme assays, localization of ADH in the root tissue was examined cytochemically. The results of these analyses showed that ADH activity increased significantly as a result of spaceflight exposure. Enzyme activity increased 248% to 304% in dwarf wheat when compared with the ground controls and Brassica showed increases between 334% and 579% when compared with day zero controls. Cytochemical staining revealed no differences in ADH tissue localization in any of the dwarf wheat treatments. These results show the importance of considering root system oxygenation in designing and building nutrient delivery hardware for spaceflight plant cultivation and confirm previous reports of an ADH response associated with spaceflight exposure.

  18. Competing neighbors: light perception and root function.

    PubMed

    Gundel, Pedro E; Pierik, Ronald; Mommer, Liesje; Ballaré, Carlos L

    2014-09-01

    Plant responses to competition have often been described as passive consequences of reduced resource availability. However, plants have mechanisms to forage for favorable conditions and anticipate competition scenarios. Despite the progresses made in understanding the role of light signaling in modulating plant-plant interactions, little is known about how plants use and integrate information gathered by their photoreceptors aboveground to regulate performance belowground. Given that the phytochrome family of photoreceptors plays a key role in the acquisition of information about the proximity of neighbors and canopy cover, it is tempting to speculate that changes in the red:far-red (R:FR) ratio perceived by aboveground plant parts have important implications shaping plant behavior belowground. Exploring data from published experiments, we assess the neglected role of light signaling in the control of root function. The available evidence indicates that plant exposure to low R:FR ratios affects root growth and morphology, root exudate profiles, and interactions with beneficial soil microorganisms. Although dependent on species identity, signals perceived aboveground are likely to affect root-to-root interactions. Root systems could also be guided to deploy new growth predominantly in open areas by light signals perceived by the shoots. Studying interactions between above- and belowground plant-plant signaling is expected to improve our understanding of the mechanisms of plant competition. PMID:24894371

  19. Adaptive significance of root grafting in trees

    SciTech Connect

    Loehle, C.; Jones, R.

    1988-12-31

    Root grafting has long been observed in forest trees but the adaptive significance of this trait has not been fully explained. Various authors have proposed that root grafting between trees contributes to mechanical support by linking adjacent root systems. Keeley proposes that this trait would be of greatest advantage in swamps where soils provide poor mechanical support. He provides as evidence a greenhouse study of Nyssa sylvatica Marsh in which seedlings of swamp provenance formed between-individual root grafts more frequently than upland provenance seedlings. In agreement with this within-species study, Keeley observed that arid zone species rarely exhibit grafts. Keeley also demonstrated that vines graft less commonly than trees, and herbs never do. Since the need for mechanical support coincides with this trend, these data seem to support his model. In this paper, the authors explore the mechanisms and ecological significance of root grafting, leading to predictions of root grafting incidence. Some observations support and some contradict the mechanical support hypothesis.

  20. Capturing Arabidopsis root architecture dynamics with ROOT-FIT reveals diversity in responses to salinity.

    PubMed

    Julkowska, Magdalena M; Hoefsloot, Huub C J; Mol, Selena; Feron, Richard; de Boer, Gert-Jan; Haring, Michel A; Testerink, Christa

    2014-11-01

    The plant root is the first organ to encounter salinity stress, but the effect of salinity on root system architecture (RSA) remains elusive. Both the reduction in main root (MR) elongation and the redistribution of the root mass between MRs and lateral roots (LRs) are likely to play crucial roles in water extraction efficiency and ion exclusion. To establish which RSA parameters are responsive to salt stress, we performed a detailed time course experiment in which Arabidopsis (Arabidopsis thaliana) seedlings were grown on agar plates under different salt stress conditions. We captured RSA dynamics with quadratic growth functions (root-fit) and summarized the salt-induced differences in RSA dynamics in three growth parameters: MR elongation, average LR elongation, and increase in number of LRs. In the ecotype Columbia-0 accession of Arabidopsis, salt stress affected MR elongation more severely than LR elongation and an increase in LRs, leading to a significantly altered RSA. By quantifying RSA dynamics of 31 different Arabidopsis accessions in control and mild salt stress conditions, different strategies for regulation of MR and LR meristems and root branching were revealed. Different RSA strategies partially correlated with natural variation in abscisic acid sensitivity and different Na(+)/K(+) ratios in shoots of seedlings grown under mild salt stress. Applying root-fit to describe the dynamics of RSA allowed us to uncover the natural diversity in root morphology and cluster it into four response types that otherwise would have been overlooked. PMID:25271266

  1. Comparative behavior of root pathogens in stems and roots of southeastern Pinus species.

    PubMed

    Matusick, George; Nadel, Ryan L; Walker, David M; Hossain, Mohammad J; Eckhardt, Lori G

    2016-04-01

    Root diseases are expected to become a greater threat to trees in the future due to accidental pathogen introductions and predicted climate changes, thus there is a need for accurate and efficient pathogenicity tests. For many root pathogens, these tests have been conducted in stems instead of roots. It, however, remains unclear whether stem and root inoculations are comparable for most fungal species. In this study we compared the growth and damage caused by five root pathogens (Grosmannia huntii, Grosmannia alacris, Leptographium procerum, Leptographium terebrantis, and Heterobasidion irregulare) in root and stem tissue of two Pinus species by inoculating mature trees and tissue amended agar in the laboratory. Most fungal species tested caused greater damage in roots of both pine hosts following inoculation. The relationship between root and stem damage was, however, similar when most combinations of pathogens were compared. These results suggest that although stem inoculations are not suitable for determining the actual damage potential of a given species, they may be viewed as a useful surrogate for root inoculations when comparing the relative pathogenicity of multiple species. When grown on amended agar, fungal species generally had greater growth in stem tissue, contrasting with the findings from tree inoculations. PMID:27020149

  2. Melatonin promotes seminal root elongation and root growth in transgenic rice after germination.

    PubMed

    Park, Sangkyu; Back, Kyoungwhan

    2012-11-01

    The effect of melatonin on root growth after germination was examined in transgenic rice seedlings expressing sheep serotonin N-acetyltransferase (NAT). Enhanced melatonin levels were found in T(3) homozygous seedlings because of the ectopic overexpression of sheep NAT, which is believed to be the rate-limiting enzyme in melatonin biosynthesis in animals. Compared with wild-type rice seeds, the transgenic rice seeds showed enhanced seminal root growth and an analogous number of adventitious roots 4 and 10 days after seeding on half-strength Murashige and Skoog medium. The enhanced initial seminal root growth in the transgenic seedlings matched their increased root biomass well. We also found that treatment with 0.5 and 1 μM melatonin promoted seminal root growth of the wild type under continuous light. These results indicate that melatonin plays an important role in regulating both seminal root length and root growth after germination in monocotyledonous rice plants. This is the first report on the effects of melatonin on root growth in gain-of-function mutant plants that produce high levels of melatonin. PMID:22640001

  3. Earliest rooting system and root : shoot ratio from a new Zosterophyllum plant.

    PubMed

    Hao, Shougang; Xue, Jinzhuang; Guo, Dali; Wang, Deming

    2010-01-01

    The enhanced chemical weathering by rooted vascular plants during the Silurian-Devonian period played a crucial role in altering global biogeochemical cycles and atmospheric environments; however, the documentation of early root morphology and physiology is scarce because the existing fossils are mostly incomplete. Here, we report an entire, uprooted specimen of a new Zosterophyllum Penhallow, named as Z. shengfengense, from the Early Devonian Xitun Formation (Lochkovian, c. 413 Myr old) of Yunnan, south China. This plant has the most ancient known record of a rooting system. The plant consists of aerial axes of 98 mm in height, showing a tufted habit, and a rhizome bearing a fibrous-like rooting system, c. 20 mm in length. The rhizome shows masses of branchings, which produce upwardly directed aerial axes and downwardly directed root-like axes. The completeness of Z. shengfengense made it possible to estimate the biomass allocation and root : shoot ratio. The root : shoot ratio of this early plant is estimated at a mean value of 0.028, and the root-like axes constitute only c. 3% of the total biomass. Zosterophyllum shengfengense was probably a semi-aquatic plant with efficient water use or a strong uptake capacity of the root-like axes. PMID:19825018

  4. New insights to lateral rooting: Differential responses to heterogeneous nitrogen availability among maize root types.

    PubMed

    Yu, Peng; White, Philip J; Li, Chunjian

    2015-01-01

    Historical domestication and the "Green revolution" have both contributed to the evolution of modern, high-performance crops. Together with increased irrigation and application of chemical fertilizers, these efforts have generated sufficient food for the growing global population. Root architecture, and in particular root branching, plays an important role in the acquisition of water and nutrients, plant performance, and crop yield. Better understanding of root growth and responses to the belowground environment could contribute to overcoming the challenges faced by agriculture today. Manipulating the abilities of crop root systems to explore and exploit the soil environment could enable plants to make the most of soil resources, increase stress tolerance and improve grain yields, while simultaneously reducing environmental degradation. In this article it is noted that the control of root branching, and the responses of root architecture to nitrate availability, differ between root types and between plant species. Since the control of root branching depends upon both plant species and root type, further work is urgently required to determine the appropriate genes to manipulate to improve resource acquisition by specific crops. PMID:26443081

  5. RootNav: Navigating Images of Complex Root Architectures1[C][W

    PubMed Central

    Pound, Michael P.; French, Andrew P.; Atkinson, Jonathan A.; Wells, Darren M.; Bennett, Malcolm J.; Pridmore, Tony

    2013-01-01

    We present a novel image analysis tool that allows the semiautomated quantification of complex root system architectures in a range of plant species grown and imaged in a variety of ways. The automatic component of RootNav takes a top-down approach, utilizing the powerful expectation maximization classification algorithm to examine regions of the input image, calculating the likelihood that given pixels correspond to roots. This information is used as the basis for an optimization approach to root detection and quantification, which effectively fits a root model to the image data. The resulting user experience is akin to defining routes on a motorist’s satellite navigation system: RootNav makes an initial optimized estimate of paths from the seed point to root apices, and the user is able to easily and intuitively refine the results using a visual approach. The proposed method is evaluated on winter wheat (Triticum aestivum) images (and demonstrated on Arabidopsis [Arabidopsis thaliana], Brassica napus, and rice [Oryza sativa]), and results are compared with manual analysis. Four exemplar traits are calculated and show clear illustrative differences between some of the wheat accessions. RootNav, however, provides the structural information needed to support extraction of a wider variety of biologically relevant measures. A separate viewer tool is provided to recover a rich set of architectural traits from RootNav’s core representation. PMID:23766367

  6. New insights to lateral rooting: Differential responses to heterogeneous nitrogen availability among maize root types

    PubMed Central

    Yu, Peng; White, Philip J; Li, Chunjian

    2015-01-01

    Historical domestication and the "Green revolution" have both contributed to the evolution of modern, high-performance crops. Together with increased irrigation and application of chemical fertilizers, these efforts have generated sufficient food for the growing global population. Root architecture, and in particular root branching, plays an important role in the acquisition of water and nutrients, plant performance, and crop yield. Better understanding of root growth and responses to the belowground environment could contribute to overcoming the challenges faced by agriculture today. Manipulating the abilities of crop root systems to explore and exploit the soil environment could enable plants to make the most of soil resources, increase stress tolerance and improve grain yields, while simultaneously reducing environmental degradation. In this article it is noted that the control of root branching, and the responses of root architecture to nitrate availability, differ between root types and between plant species. Since the control of root branching depends upon both plant species and root type, further work is urgently required to determine the appropriate genes to manipulate to improve resource acquisition by specific crops. PMID:26443081

  7. Ozone decreases spring root growth and root carbohydrate content in ponderosa pine the year following exposure

    SciTech Connect

    Andersen, C.P.; Hogsett, W.E.; Wessling, R.; Plocher, M.

    1991-01-01

    Storage carbohydrates are extremely important for new shoot and root development following dormancy or during periods of high stress. The hypothesis that ozone decreases carbohydrate storage and decreases new root growth during the year following exposure was investigated. The results suggest that (1) ponderosa pine seedlings exposed to 122 and 169 ppm hrs ozone for one season have significantly less root starch reserves available just prior to and during bud break the following year, and (2) spring root growth is decreased following ozone exposure. The carry-over effects of ozone stress may be important in long-lived perennial species which are annually subjected to ozone.

  8. Modelling water uptake efficiency of root systems

    NASA Astrophysics Data System (ADS)

    Leitner, Daniel; Tron, Stefania; Schröder, Natalie; Bodner, Gernot; Javaux, Mathieu; Vanderborght, Jan; Vereecken, Harry; Schnepf, Andrea

    2016-04-01

    Water uptake is crucial for plant productivity. Trait based breeding for more water efficient crops will enable a sustainable agricultural management under specific pedoclimatic conditions, and can increase drought resistance of plants. Mathematical modelling can be used to find suitable root system traits for better water uptake efficiency defined as amount of water taken up per unit of root biomass. This approach requires large simulation times and large number of simulation runs, since we test different root systems under different pedoclimatic conditions. In this work, we model water movement by the 1-dimensional Richards equation with the soil hydraulic properties described according to the van Genuchten model. Climatic conditions serve as the upper boundary condition. The root system grows during the simulation period and water uptake is calculated via a sink term (after Tron et al. 2015). The goal of this work is to compare different free software tools based on different numerical schemes to solve the model. We compare implementations using DUMUX (based on finite volumes), Hydrus 1D (based on finite elements), and a Matlab implementation of Van Dam, J. C., & Feddes 2000 (based on finite differences). We analyse the methods for accuracy, speed and flexibility. Using this model case study, we can clearly show the impact of various root system traits on water uptake efficiency. Furthermore, we can quantify frequent simplifications that are introduced in the modelling step like considering a static root system instead of a growing one, or considering a sink term based on root density instead of considering the full root hydraulic model (Javaux et al. 2008). References Tron, S., Bodner, G., Laio, F., Ridolfi, L., & Leitner, D. (2015). Can diversity in root architecture explain plant water use efficiency? A modeling study. Ecological modelling, 312, 200-210. Van Dam, J. C., & Feddes, R. A. (2000). Numerical simulation of infiltration, evaporation and shallow

  9. Root Exudates from Grafted-Root Watermelon Showed a Certain Contribution in Inhibiting Fusarium oxysporum f. sp. niveum

    PubMed Central

    Wang, Dongsheng; Mao, Jiugeng; Huang, Qiwei; Guo, Shiwei; Shen, Qirong

    2013-01-01

    Grafting watermelon onto bottle gourd rootstock is commonly used method to generate resistance to Fusarium oxysporum f. sp. niveum (FON), but knowledge of the effect of the root exudates of grafted watermelon on this soil-borne pathogen in rhizosphere remains limited. To investigate the root exudate profiles of the own-root bottle gourd, grafted-root watermelon and own-root watermelon, recirculating hydroponic culture system was developed to continuously trap these root exudates. Both conidial germination and growth of FON were significantly decreased in the presence of root exudates from the grafted-root watermelon compared with the own-root watermelon. HPLC analysis revealed that the composition of the root exudates released by the grafted-root watermelon differed not only from the own-root watermelon but also from the bottle gourd rootstock plants. We identified salicylic acid in all 3 root exudates, chlorogenic acid and caffeic acid in root exudates from own-root bottle gourd and grafted-root watermelon but not own-root watermelon, and abundant cinnamic acid only in own-root watermelon root exudates. The chlorogenic and caffeic acid were candidates for potentiating the enhanced resistance of the grafted watermelon to FON, therefore we tested the effects of the two compounds on the conidial germination and growth of FON. Both phenolic acids inhibited FON conidial germination and growth in a dose-dependent manner, and FON was much more susceptible to chlorogenic acid than to caffeic acid. In conclusion, the key factor in attaining the resistance to Fusarium wilt is grafting on the non-host root stock, however, the root exudates profile also showed some contribution in inhibiting FON. These results will help to better clarify the disease resistance mechanisms of grafted-root watermelon based on plant-microbe communication and will guide the improvement of strategies against Fusarium-mediated wilt of watermelon plants. PMID:23700421

  10. Root exudates from grafted-root watermelon showed a certain contribution in inhibiting Fusarium oxysporum f. sp. niveum.

    PubMed

    Ling, Ning; Zhang, Wenwen; Wang, Dongsheng; Mao, Jiugeng; Huang, Qiwei; Guo, Shiwei; Shen, Qirong

    2013-01-01

    Grafting watermelon onto bottle gourd rootstock is commonly used method to generate resistance to Fusarium oxysporum f. sp. niveum (FON), but knowledge of the effect of the root exudates of grafted watermelon on this soil-borne pathogen in rhizosphere remains limited. To investigate the root exudate profiles of the own-root bottle gourd, grafted-root watermelon and own-root watermelon, recirculating hydroponic culture system was developed to continuously trap these root exudates. Both conidial germination and growth of FON were significantly decreased in the presence of root exudates from the grafted-root watermelon compared with the own-root watermelon. HPLC analysis revealed that the composition of the root exudates released by the grafted-root watermelon differed not only from the own-root watermelon but also from the bottle gourd rootstock plants. We identified salicylic acid in all 3 root exudates, chlorogenic acid and caffeic acid in root exudates from own-root bottle gourd and grafted-root watermelon but not own-root watermelon, and abundant cinnamic acid only in own-root watermelon root exudates. The chlorogenic and caffeic acid were candidates for potentiating the enhanced resistance of the grafted watermelon to FON, therefore we tested the effects of the two compounds on the conidial germination and growth of FON. Both phenolic acids inhibited FON conidial germination and growth in a dose-dependent manner, and FON was much more susceptible to chlorogenic acid than to caffeic acid. In conclusion, the key factor in attaining the resistance to Fusarium wilt is grafting on the non-host root stock, however, the root exudates profile also showed some contribution in inhibiting FON. These results will help to better clarify the disease resistance mechanisms of grafted-root watermelon based on plant-microbe communication and will guide the improvement of strategies against Fusarium-mediated wilt of watermelon plants. PMID:23700421

  11. Disentangling root system responses to neighbours: identification of novel root behavioural strategies.

    PubMed

    Belter, Pamela R; Cahill, James F

    2015-01-01

    Plants live in a social environment, with interactions among neighbours a ubiquitous aspect of life. Though many of these interactions occur in the soil, our understanding of how plants alter root growth and the patterns of soil occupancy in response to neighbours is limited. This is in contrast to a rich literature on the animal behavioural responses to changes in the social environment. For plants, root behavioural changes that alter soil occupancy patterns can influence neighbourhood size and the frequency or intensity of competition for soil resources; issues of fundamental importance to understanding coexistence and community assembly. Here we report a large comparative study in which individuals of 20 species were grown with and without each of two neighbour species. Through repeated root visualization and analyses, we quantified many putative root behaviours, including the extent to which each species altered aspects of root system growth (e.g. rooting breadth, root length, etc.) in response to neighbours. Across all species, there was no consistent behavioural response to neighbours (i.e. no general tendencies towards root over-proliferation nor avoidance). However, there was a substantial interspecific variation showing a continuum of behavioural variation among the 20 species. Multivariate analyses revealed two novel and predominant root behavioural strategies: (i) size-sensitivity, in which focal plants reduced their overall root system size in response to the presence of neighbours, and (ii) location-sensitivity, where focal plants adjusted the horizontal and vertical placement of their roots in response to neighbours. Of these, size-sensitivity represents the commonly assumed response to competitive encounters-reduced growth. However, location sensitivity is not accounted for in classic models and concepts of plant competition, though it is supported from recent work in plant behavioural ecology. We suggest that these different strategies could have

  12. Disentangling root system responses to neighbours: identification of novel root behavioural strategies

    PubMed Central

    Belter, Pamela R.; Cahill, James F.

    2015-01-01

    Plants live in a social environment, with interactions among neighbours a ubiquitous aspect of life. Though many of these interactions occur in the soil, our understanding of how plants alter root growth and the patterns of soil occupancy in response to neighbours is limited. This is in contrast to a rich literature on the animal behavioural responses to changes in the social environment. For plants, root behavioural changes that alter soil occupancy patterns can influence neighbourhood size and the frequency or intensity of competition for soil resources; issues of fundamental importance to understanding coexistence and community assembly. Here we report a large comparative study in which individuals of 20 species were grown with and without each of two neighbour species. Through repeated root visualization and analyses, we quantified many putative root behaviours, including the extent to which each species altered aspects of root system growth (e.g. rooting breadth, root length, etc.) in response to neighbours. Across all species, there was no consistent behavioural response to neighbours (i.e. no general tendencies towards root over-proliferation nor avoidance). However, there was a substantial interspecific variation showing a continuum of behavioural variation among the 20 species. Multivariate analyses revealed two novel and predominant root behavioural strategies: (i) size-sensitivity, in which focal plants reduced their overall root system size in response to the presence of neighbours, and (ii) location-sensitivity, where focal plants adjusted the horizontal and vertical placement of their roots in response to neighbours. Of these, size-sensitivity represents the commonly assumed response to competitive encounters—reduced growth. However, location sensitivity is not accounted for in classic models and concepts of plant competition, though it is supported from recent work in plant behavioural ecology. We suggest that these different strategies could have

  13. How do roots elongate in a structured soil?

    PubMed

    Jin, Kemo; Shen, Jianbo; Ashton, Rhys W; Dodd, Ian C; Parry, Martin A J; Whalley, William R

    2013-11-01

    In this review, we examine how roots penetrate a structured soil. We first examine the relationship between soil water status and its mechanical strength, as well as the ability of the soil to supply water to the root. We identify these as critical soil factors, because it is primarily in drying soil that mechanical constraints limit root elongation. Water supply to the root is important because root water status affects growth pressures and root stiffness. To simplify the bewildering complexity of soil-root interactions, the discussion is focused around the special cases of root elongation in soil with pores much smaller than the root diameter and the penetration of roots at interfaces within the soil. While it is often assumed that the former case is well understood, many unanswered questions remain. While low soil-root friction is often viewed as a trait conferring better penetration of strong soils, it may also increase the axial pressure on the root tip and in so doing reduce the rate of cell division and/or expansion. The precise trade-off between various root traits involved in root elongation in homogeneous soil remains to be determined. There is consensus that the most important factors determining root penetration at an interface are the angle at which the root attempts to penetrate the soil, root stiffness, and the strength of the soil to be penetrated. The effect of growth angle on root penetration implicates gravitropic responses in improved root penetration ability. Although there is no work that has explored the effect of the strength of the gravitropic responses on penetration of hard layers, we attempt to outline possible interactions. Impacts of soil drying and strength on phytohormone concentrations in roots, and consequent root-to-shoot signalling, are also considered. PMID:24043852

  14. TSkim : A tool for skimming ROOT trees

    NASA Astrophysics Data System (ADS)

    Chamont, David

    2010-04-01

    Like many HEP researchers, the members of the Fermi collaboration have chosen to store their experiment data within ROOT trees. A frequent activity of such physicists is the tuning of selection criteria which define the events of interest, thus cutting and pruning the ROOT trees so to extract all the data linked to those specific physical events. It is rather straightforward to write a ROOT script to skim a single kind of data, for example the raw measurements of Fermi LAT detector. This proves to be trickier if one wants to process also some simulated or analysis data at the same time, because each kind of data is structured with its own rules for what concerns file names and sizes, tree names, identification of events, etc. TSkim has been designed to facilitate this task. Thanks to a user-defined configuration file which says where to find the run and event identifications in the different kind of trees, TSkim is able to collect all the tree elements which match a given ROOT cut. The tool will also help when loading the shared libraries which describe the experiment data, or when pruning the tree branches. Initially a pair of PERL and ROOT scripts, TSkim is today a fully compiled C++ application, enclosing our ROOT know-how and offering a panel of features going far beyond the original Fermi requirements. In this manuscript, we present TSkim concepts and key features, including a new kind of event list. Any collaboration using ROOT IO could profit from the use of this tool.

  15. The evolution of root hairs and rhizoids

    PubMed Central

    Jones, Victor A.S.; Dolan, Liam

    2012-01-01

    Background Almost all land plants develop tip-growing filamentous cells at the interface between the plant and substrate (the soil). Root hairs form on the surface of roots of sporophytes (the multicellular diploid phase of the life cycle) in vascular plants. Rhizoids develop on the free-living gametophytes of vascular and non-vascular plants and on both gametophytes and sporophytes of the extinct rhyniophytes. Extant lycophytes (clubmosses and quillworts) and monilophytes (ferns and horsetails) develop both free-living gametophytes and free-living sporophytes. These gametophytes and sporophytes grow in close contact with the soil and develop rhizoids and root hairs, respectively. Scope Here we review the development and function of rhizoids and root hairs in extant groups of land plants. Root hairs are important for the uptake of nutrients with limited mobility in the soil such as phosphate. Rhizoids have a variety of functions including water transport and adhesion to surfaces in some mosses and liverworts. Conclusions A similar gene regulatory network controls the development of rhizoids in moss gametophytes and root hairs on the roots of vascular plant sporophytes. It is likely that this gene regulatory network first operated in the gametophyte of the earliest land plants. We propose that later it functioned in sporophytes as the diploid phase evolved a free-living habit and developed an interface with the soil. This transference of gene function from gametophyte to sporophyte could provide a mechanism that, at least in part, explains the increase in morphological diversity of sporophytes that occurred during the radiation of land plants in the Devonian Period. PMID:22730024

  16. Ecological Hypothesis of Dentin and Root Caries.

    PubMed

    Takahashi, Nobuhiro; Nyvad, Bente

    2016-01-01

    Recent advances regarding the caries process indicate that ecological phenomena induced by bacterial acid production tilt the de- and remineralization balance of the dental hard tissues towards demineralization through bacterial acid-induced adaptation and selection within the microbiota - from the dynamic stability stage to the aciduric stage via the acidogenic stage [Takahashi and Nyvad, 2008]. Dentin and root caries can also be partly explained by this hypothesis; however, the fact that these tissues contain a considerable amount of organic material suggests that protein degradation is involved in caries formation. In this review, we compiled relevant histological, biochemical, and microbiological information about dentin/root caries and refined the hypothesis by adding degradation of the organic matrix (the proteolytic stage) to the abovementioned stages. Bacterial acidification not only induces demineralization and exposure of the organic matrix in dentin/root surfaces but also activation of dentin-embedded and salivary matrix metalloproteinases and cathepsins. These phenomena initiate degradation of the demineralized organic matrix in dentin/root surfaces. While a bacterial involvement has never been confirmed in the initial degradation of organic material, the detection of proteolytic/amino acid-degrading bacteria and bacterial metabolites in dentin and root caries suggests a bacterial digestion and metabolism of partly degraded matrix. Moreover, bacterial metabolites might induce pulpitis as an inflammatory/immunomodulatory factor. Root and dentin surfaces are always at risk of becoming demineralized in the oral cavity, and exposed organic materials can be degraded by host-derived proteases contained in saliva and dentin itself. New approaches to the prevention and treatment of root/dentin caries are required. PMID:27458979

  17. How can science education foster students' rooting?

    NASA Astrophysics Data System (ADS)

    Østergaard, Edvin

    2015-06-01

    The question of how to foster rooting in science education points towards a double challenge; efforts to prevent (further) uprooting and efforts to promote rooting/re-rooting. Wolff-Michael Roth's paper discusses the uprooting/rooting pair of concepts, students' feeling of alienation and loss of fundamental sense of the earth as ground, and potential consequences for teaching science in a rooted manner. However, the argumentation raises a number of questions which I try to answer. My argumentation rests on Husserl's critique of science and the "ontological reversal", an ontological position where abstract models from science are considered as more real than the everyday reality itself, where abstract, often mathematical, models are taken to be the real causes behind everyday experiences. In this paper, measures towards an "ontological re-reversal" are discussed by drawing on experiences from phenomenon-based science education. I argue that perhaps the most direct and productive way of promoting rooting in science class is by intentionally cultivating the competencies of sensing and aesthetic experience. An aesthetic experience is defined as a precognitive, sensuous experience, an experience that is opened up for through sensuous perception. Conditions for rooting in science education is discussed against three challenges: Restoring the value of aesthetic experience, allowing time for open inquiry and coping with curriculum. Finally, I raise the question whether dimensions like "reality" or "nature" are self-evident for students. In the era of constructivism, with its focus on cognition and knowledge building, the inquiry process itself has become more important than the object of inquiry. I argue that as educators of science teachers we have to emphasize more explicitly "the nature of nature" as a field of exploration.

  18. Shoot-derived abscisic acid promotes root growth.

    PubMed

    McAdam, Scott A M; Brodribb, Timothy J; Ross, John J

    2016-03-01

    The phytohormone abscisic acid (ABA) plays a major role in regulating root growth. Most work to date has investigated the influence of root-sourced ABA on root growth during water stress. Here, we tested whether foliage-derived ABA could be transported to the roots, and whether this foliage-derived ABA had an influence on root growth under well-watered conditions. Using both application studies of deuterium-labelled ABA and reciprocal grafting between wild-type and ABA-biosynthetic mutant plants, we show that both ABA levels in the roots and root growth in representative angiosperms are controlled by ABA synthesized in the leaves rather than sourced from the roots. Foliage-derived ABA was found to promote root growth relative to shoot growth but to inhibit the development of lateral roots. Increased root auxin (IAA) levels in plants with ABA-deficient scions suggest that foliage-derived ABA inhibits root growth through the root growth-inhibitor IAA. These results highlight the physiological and morphological importance, beyond the control of stomata, of foliage-derived ABA. The use of foliar ABA as a signal for root growth has important implications for regulating root to shoot growth under normal conditions and suggests that leaf rather than root hydration is the main signal for regulating plant responses to moisture. PMID:26514625

  19. Rhizoctonia damping-off stem canker and root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani has been reported to cause damping-off and root rot of rhododendrons and azaleas. Damping-off often includes groups of dying and dead seedlings. Decline of rooted plants in containers results from both root rot and stem necrosis below or above the soil line. Root rot is usually no...

  20. ROOTBOX FOR QUANTITATIVE OBSERVATIONS ON INTACT ENTIRE ROOT SYSTEMS

    EPA Science Inventory

    A rootbox is described which allows observation of an intact, entire root system. oots are sandwiched against a plexiglass surface by a nylon mesh that is impermeable to roots, but permeable to water and nutrients. o quantify root growth non-destructively, roots of different size...

  1. Cold temperature delays wound healing in postharvest sugarbeet roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Storage temperature affects the rate and extent of wound-healing in a number of root and tuber crops. The effect of storage temperature on wound-healing in sugarbeet (Beta vulgaris L.) roots, however, is largely unknown. Wound-healing of sugarbeet roots was investigated using surface-abraded roots s...

  2. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  3. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  4. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  5. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  6. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  7. How up- or downslope anchoring affects root reinforcement

    NASA Astrophysics Data System (ADS)

    Giadrossich, Filippo; Schwarz, Massimiliano; Cohen, Denis; Niedda, Marcello

    2016-04-01

    Root reinforcement is important for slope stability. In addition to the important contribution of roots to shear strength along the slip surface, root networks are also recognized to impart stabilization through lateral (parallel to slope) redistribution of forces under tension. The most common method to measure lateral root reinforcement is a pullout test where one root or a bundle of root is pulled out of the soil matrix. This condition represents the case where roots within the mass of a landslide slip out from the upper stable part of the slope. There is also, however, the situation where roots anchored in the upper stable part of the slope slip out from the sliding mass. In the latter it is difficult to quantify root reinforcement and no study has discussed this mechanism. We carried out a new series of laboratory and field experiments using Douglas fir (Pseudotsuga menziesii) roots to quantify how up- or downslope anchoring affects root reinforcement. In addition, we carried out new field pullout tests on coarse roots (larger that 2 mm in diameter, up to 47 mm). Then, considering the state-of-the-art of root reinforcement modeling (the Root Bundle Model), we integrated results from our measurements into the model to verify the magnitude of this effect on overall root reinforcement at the stand scale. Results indicate that the ratio between pullout force and force transferred to the root during soil slip ranges between 0.5 and 1. This indicates that measured pullout force always overestimate the contribution of lateral slipping out roots in situations where the soil slide from anchored roots. This is general the case for root with diameter up to 3-4 mm. Root-size distribution is also a key factor influencing root reinforcement at the forest-stand scale. As most coarse roots break along tension cracks while fine roots slip out, the effect discussed in this study on root reinforcement modeling is negligible when coarse-root diameter classes are represented. Our

  8. Identification of coniferous fine roots to species using ribosomal PCR products of pooled root samples

    EPA Science Inventory

    Background/Question/Methods To inform an individual-based forest stand model emphasizing belowground competition, we explored the potential of using the relative abundances of ribosomal PCR products from pooled and milled roots, to allocate total root biomass to each of the thre...

  9. ROOT DENSITY AND ROOT SURFACE AREA OF SELECTED PACIFIC NORTHWEST CROPS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Root length density and root surface area were evaluated for soft white winter and spring wheat (Triticum aestivum L), spring peas (Pisum sativum) and winter canola (Brassica napus L.) for at least two years at two locations (Pendleton, OR and Pullman, WA). Spring wheat was sampled at 3-leaf, anthe...

  10. Roots Withstanding their Environment: Exploiting Root System Architecture Responses to Abiotic Stress to Improve Crop Tolerance

    PubMed Central

    Koevoets, Iko T.; Venema, Jan Henk; Elzenga, J. Theo. M.; Testerink, Christa

    2016-01-01

    To face future challenges in crop production dictated by global climate changes, breeders and plant researchers collaborate to develop productive crops that are able to withstand a wide range of biotic and abiotic stresses. However, crop selection is often focused on shoot performance alone, as observation of root properties is more complex and asks for artificial and extensive phenotyping platforms. In addition, most root research focuses on development, while a direct link to the functionality of plasticity in root development for tolerance is often lacking. In this paper we review the currently known root system architecture (RSA) responses in Arabidopsis and a number of crop species to a range of abiotic stresses, including nutrient limitation, drought, salinity, flooding, and extreme temperatures. For each of these stresses, the key molecular and cellular mechanisms underlying the RSA response are highlighted. To explore the relevance for crop selection, we especially review and discuss studies linking root architectural responses to stress tolerance. This will provide a first step toward understanding the relevance of adaptive root development for a plant’s response to its environment. We suggest that functional evidence on the role of root plasticity will support breeders in their efforts to include root properties in their current selection pipeline for abiotic stress tolerance, aimed to improve the robustness of crops.

  11. Root system markup language: toward a unified root architecture description language.

    PubMed

    Lobet, Guillaume; Pound, Michael P; Diener, Julien; Pradal, Christophe; Draye, Xavier; Godin, Christophe; Javaux, Mathieu; Leitner, Daniel; Meunier, Félicien; Nacry, Philippe; Pridmore, Tony P; Schnepf, Andrea

    2015-03-01

    The number of image analysis tools supporting the extraction of architectural features of root systems has increased in recent years. These tools offer a handy set of complementary facilities, yet it is widely accepted that none of these software tools is able to extract in an efficient way the growing array of static and dynamic features for different types of images and species. We describe the Root System Markup Language (RSML), which has been designed to overcome two major challenges: (1) to enable portability of root architecture data between different software tools in an easy and interoperable manner, allowing seamless collaborative work; and (2) to provide a standard format upon which to base central repositories that will soon arise following the expanding worldwide root phenotyping effort. RSML follows the XML standard to store two- or three-dimensional image metadata, plant and root properties and geometries, continuous functions along individual root paths, and a suite of annotations at the image, plant, or root scale at one or several time points. Plant ontologies are used to describe botanical entities that are relevant at the scale of root system architecture. An XML schema describes the features and constraints of RSML, and open-source packages have been developed in several languages (R, Excel, Java, Python, and C#) to enable researchers to integrate RSML files into popular research workflow. PMID:25614065

  12. Deep rooting conferred by DEEPER ROOTING 1 enhances rice yield in paddy fields.

    PubMed

    Arai-Sanoh, Yumiko; Takai, Toshiyuki; Yoshinaga, Satoshi; Nakano, Hiroshi; Kojima, Mikiko; Sakakibara, Hitoshi; Kondo, Motohiko; Uga, Yusaku

    2014-01-01

    To clarify the effect of deep rooting on grain yield in rice (Oryza sativa L.) in an irrigated paddy field with or without fertilizer, we used the shallow-rooting IR64 and the deep-rooting Dro1-NIL (a near-isogenic line homozygous for the Kinandang Patong allele of DEEPER ROOTING 1 (DRO1) in the IR64 genetic background). Although total root length was similar in both lines, more roots were distributed within the lower soil layer of the paddy field in Dro1-NIL than in IR64, irrespective of fertilizer treatment. At maturity, Dro1-NIL showed approximately 10% higher grain yield than IR64, irrespective of fertilizer treatment. Higher grain yield of Dro1-NIL was mainly due to the increased 1000-kernel weight and increased percentage of ripened grains, which resulted in a higher harvest index. After heading, the uptake of nitrogen from soil and leaf nitrogen concentration were higher in Dro1-NIL than in IR64. At the mid-grain-filling stage, Dro1-NIL maintained higher cytokinin fluxes from roots to shoots than IR64. These results suggest that deep rooting by DRO1 enhances nitrogen uptake and cytokinin fluxes at late stages, resulting in better grain filling in Dro1-NIL in a paddy field in this study. PMID:24988911

  13. The root as a drill: an ethylene-auxin interaction facilitates root penetration in soil.

    PubMed

    Santisree, Parankusam; Nongmaithem, Sapana; Sreelakshmi, Yellamaraju; Ivanchenko, Maria; Sharma, Rameshwar

    2012-02-01

    Plant roots forage the soil for water and nutrients and overcome the soil's physical compactness. Roots are endowed with a mechanism that allows them to penetrate and grow in dense media such as soil. However, the molecular mechanisms underlying this process are still poorly understood. The nature of the media in which roots grow adds to the difficulty to in situ analyze the mechanisms underlying root penetration. Inhibition of ethylene perception by application of 1-methyl cyclopropene (1-MCP) to tomato seedlings nearly abolished the root penetration in Soilrite. The reversal of this process by auxin indicated operation of an auxin-ethylene signaling pathway in the regulation of root penetration. The tomato pct1-2 mutant that exhibits an enhanced polar transport of auxin required higher doses of 1-MCP to inhibit root penetration, indicating a pivotal role of auxin transport in this process. In this update we provide a brief review of our current understanding of molecular processes underlying root penetration in higher plants. PMID:22415043

  14. A PLANT ROOT SYSTEM ARCHITECTURAL TAXONOMY: A FRAMEWORK FOR ROOT NOMENCLATURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research into root system morphology over the last two centuries, has developed a diverse set of terminologies that are difficult to apply consistently across species and research specialties. In response to a need for better communication, a workshop held by the International Society for Root Rese...

  15. Root traits associated with Phytophthora root rot resistance in red raspberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytophthora root rot is a serious problem for commercial production of red raspberry. A study was initiated in 2009 to identify root traits in raspberry associated with little or no Phytophthora infection so that the traits can be selected and incorporated into breeding material to develop new cul...

  16. Investigating Whole Root Systems: Advances in Root Quantification Tools and Techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficient quantification of root traits remains a critical factor in exploiting many genetic resources during the study of root function and development. This is particularly true for the high throughput phenotyping of large populations for acid soil tolerance, including aluminum (Al) tolerance...

  17. Response of grape root borer (lepidoptera: sesiidae) neonates to root extracts from vitaceae species and rootstocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Observations at regular intervals of the location of newly hatched grape root borer larvae moving freely within Petri dish bioassays were used to measure and compare their response to filter paper discs treated with ethanol- and hexane-based extracts of roots from known and potential Vitaceae hosts ...

  18. Root System Markup Language: Toward a Unified Root Architecture Description Language1[OPEN

    PubMed Central

    Pound, Michael P.; Pradal, Christophe; Draye, Xavier; Godin, Christophe; Leitner, Daniel; Meunier, Félicien; Pridmore, Tony P.; Schnepf, Andrea

    2015-01-01

    The number of image analysis tools supporting the extraction of architectural features of root systems has increased in recent years. These tools offer a handy set of complementary facilities, yet it is widely accepted that none of these software tools is able to extract in an efficient way the growing array of static and dynamic features for different types of images and species. We describe the Root System Markup Language (RSML), which has been designed to overcome two major challenges: (1) to enable portability of root architecture data between different software tools in an easy and interoperable manner, allowing seamless collaborative work; and (2) to provide a standard format upon which to base central repositories that will soon arise following the expanding worldwide root phenotyping effort. RSML follows the XML standard to store two- or three-dimensional image metadata, plant and root properties and geometries, continuous functions along individual root paths, and a suite of annotations at the image, plant, or root scale at one or several time points. Plant ontologies are used to describe botanical entities that are relevant at the scale of root system architecture. An XML schema describes the features and constraints of RSML, and open-source packages have been developed in several languages (R, Excel, Java, Python, and C#) to enable researchers to integrate RSML files into popular research workflow. PMID:25614065

  19. [Coronal repositioning of root fragment by root elongation with a titanium endodontic implant].

    PubMed

    Bühler, H

    1990-12-01

    Teeth with deep transverse or oblique root fractures can nowadays be preserved by intra-alveolar transplantation. This method, however, has its limitation: The apical root fragment must not be too short in proportion to the crown length. This report describes a method to retain even very short roots. 14 roots have been carefully extracted. Then, the following treatment has been performed extraorally: Apectomy, lengthening of the root with a common titanium root screw and replantation of the root in an extruded position which allowed to carry out correct root filling and crown reconstruction. After an average observation period of 19 months 11 cases out of 14, i.e. 79%, were successful according to the criteria stated by Kristersson and Kvint. If the long-term results turn out as promising as the short-term findings, the concept might well be extended to other indications. One example is to stimulate the growth of a genuine periodontal "re-attachment" in intrabony pockets by extruding viable periodontal membrane areas to a more coronal level. PMID:2097808

  20. White lupin cluster root acclimation to phosphorus deficiency and root hair development involve unique glycerophosphodiester phosphodiesterases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White lupin (Lupinus albus L.) is a phosphate (Pi) deficiency tolerant legume which develops short, densely clustered tertiary lateral roots (cluster/proteoid roots) in response to Pi limitation. In this report we characterize two glycerophosphodiester phosphodiesterase (GPX-PDE) genes (GPX-PDE1 and...