WorldWideScience

Sample records for split-root va mycorrhizal

  1. Carbon cost of the fungal symbiont relative to net leaf P accumulation in a split-root VA mycorrhizal symbiosis

    International Nuclear Information System (INIS)

    Douds, D.D. Jr.; Johnson, C.R.; Koch, K.E.

    1988-01-01

    Translocation of 14 C-photosynthates to mycorrhizal (++), half mycorrhizal (0+), and nonmycorrhizal (00) split-root systems was compared to P accumulation in leaves of the host plant. Carrizo citrange seedlings (Poncirus trifoliata [L.] Raf. x Citrus sinensis [L.] Osbeck) were inoculated with the vesicular-arbuscular mycorrhizal fungus Glomus intraradices Schenck and Smith. Plants were exposed to 14 CO 2 for 10 minutes and ambient air for 2 hours. Three to 4% of recently labeled photosynthate was allocated to metabolism of the mycorrhiza in each inoculated root half independent of shoot P concentration, growth response, and whether one or both root halves were colonized. Nonmycorrhizal roots respired more of the label translocated to them than did mycorrhizal roots. Label recovered in the potting medium due to exudation or transport into extraradical hyphae was 5 to 6 times greater for (++) versus (00) plants. In low nutrient media, roots of (0+) and (++) plants transported more P to leaves per root weight than roots of (00) plants. However, when C translocated to roots utilized for respiration, exudation, etc., as well as growth is considered, (00) plant roots were at least as efficient at P uptake (benefit) per C utilized (cost) as (0+) and (++) plants. Root systems of (++) plants did not supply more P to leaves than (0+) plants in higher nutrient media, yet they still allocated twice the 14 C-photosynthate to the mycorrhiza as did (0+) root systems

  2. Density dependent interactions between VA mycorrhizal fungi and even-aged seedlings of two perennial Fabaceae species.

    Science.gov (United States)

    Allsopp, N; Stock, W D

    1992-08-01

    The interaction of density and mycorrhizal effects on the growth, mineral nutrition and size distribution of seedlings of two perennial members of the Fabaceae was investigated in pot culture. Seedlings of Otholobium hirtum and Aspalathus linearis were grown at densities of 1, 4, 8 and 16 plants per 13-cm pot with or without vesicular-arbuscular (VA) mycorrhizal inoculum for 120 days. Plant mass, relative growth rates, height and leaf number all decreased with increasing plant density. This was ascribed to the decreasing availability of phosphorus per plant as density increased. O. hirtum was highly dependent on mycorrhizas for P uptake but both mycorrhizal and non-mycorrhizal A. linearis seedlings were able to extract soil P with equal ease. Plant size distribution as measured by the coefficient of variation (CV) of shoot mass was greater at higher densities. CVs of mycorrhizal O. hirtum plants were higher than those of non-mycorrhizal plants. CVs of the facultatively mycorrhizal A. linearis were similar for both mycorrhizal and non-mycorrhizal plants. Higher CVs are attributed to resource preemption by larger individuals. Individuals in populations with high CVs will probably survive stress which would result in the extinction of populations with low CVs. Mass of mycorrhizal plants of both species decreased more rapidly with increasing density than did non-mycorrhizal plant mass. It is concluded that the cost of being mycorrhizal increases as plant density increases, while the benefit decreases. The results suggest that mycorrhizas will influence density-dependent population processes of faculative and obligate mycorrhizal species.

  3. Contribution of soil-32P, fertilizer-32P and VA mycorrhizal fungi to phosphorus nutrition of corn plant

    International Nuclear Information System (INIS)

    Feng Gu; Yang Maoqiu; Bai Dengsha; Huang Quansheng

    1997-01-01

    32 P labelled fertilizer and five synthetic phosphates (dicalcium phosphate, octocalcium phosphate, iron phosphate, aluminium phosphate and apatite), which were used to simulate inorganic phosphates such as Ca 2 -P, Ca 8 -P, Fe P , Al-P and Ca 10 -P in calcareous soil, were applied to corn plants inoculating with and without vesicular-arbuscular (VA) mycorrhizal fungi in a calcareous soil. The results showed that VA mycorrhizal fungi and dicalcium phosphate, octocalcium phosphate, iron phosphate, aluminium phosphate promoted growth and increased phosphorus content of corn plant. The four synthetic phosphates except apatite had higher contributions to corn plant growth than VA mycorrhizal fungi. Contributions of fertilizer-P, soil-P and synthetic phosphates to phosphorus nutrition of corn plant were in order of synthetic phosphates (except apatite) > soil- P > fertilizer-P. Inoculating with VA mycorrhizal fungi increased the contribution of soil-P and decreased the contribution of synthetic phosphates, but did not affect the contribution of fertilizer-P

  4. Osmotic Adjustment in Leaves of VA Mycorrhizal and Nonmycorrhizal Rose Plants in Response to Drought Stress.

    Science.gov (United States)

    Augé, R M; Schekel, K A; Wample, R L

    1986-11-01

    Osmotic adjustment in Rosa hybrida L. cv Samantha was characterized by the pressure-volume approach in drought-acclimated and unacclimated plants brought to the same level of drought strain, as assayed by stomatal closure. Plants were colonized by either of the vesicular-arbuscular mycorrhizal fungi Glomus deserticola Trappe, Bloss and Menge or G. intraradices Schenck and Smith, or were nonmycorrhizal. Both the acclimation and the mycorrhizal treatments decreased the osmotic potential (Psi(pi)) of leaves at full turgor and at the turgor loss point, with a corresponding increase in pressure potential at full turgor. Mycorrhizae enabled plants to maintain leaf turgor and conductance at greater tissue water deficits, and lower leaf and soil water potentials, when compared with nonmycorrhizal plants. As indicated by the Psi(pi) at the turgor loss point, the active Psi(pi) depression which attended mycorrhizal colonization alone was 0.4 to 0.6 megapascals, and mycorrhizal colonization and acclimation in concert 0.6 to 0.9 megapascals, relative to unacclimated controls without mycorrhizae. Colonization levels and sporulation were higher in plants subjected to acclimation. In unacclimated hosts, leaf water potential, water saturation deficit, and soil water potential at a particular level of drought strain were affected most by G. intraradices. G. deserticola had the greater effect after drought preconditioning.

  5. Mobilization and utilization of sparingly soluble phosphates by VA mycorrhizal fungus external hyphae I-32P indirectly labelling

    International Nuclear Information System (INIS)

    Yao Qing; Zhao Zijuan; Feng Gu; Li Xiaolin; Chen Baodong

    2000-01-01

    Red clover were grown in three-compartment boxes, and were inoculated with VA mycorrhizal fungus, Glomus mosseae. External hyphae were separated from root system by 30 μm pore size membrane. Phosphorus fertilizer indirectly labelled with 32 P and five kind of phosphates were applied in the hyphae compartment, and the ability of external hyphae to mobilize the sparingly soluble phosphates were evaluated. the results showed that external hyphae mobilized and up took Ca 2 -P, Ca 8 -P, Al-P, Fe.P, but not Ca 10 -P. The phosphorus uptake by clover from phosphates and the contribution of phosphates to clover phosphorus nutrition were ranked as Ca 2 -P > Ca 8 -P, Al-P > Fe-P

  6. Trace element toxicity in VA mycorrhizal cucumber grown on weathered coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Dosskey, M.G.; Adriano, D.C. (University of Georgia, Aiken, SC (United States). Savannah River Ecology Lab.)

    1993-11-01

    Mycorrhizal colonization is widely recognized as enhancing plant growth on severely disturbed sites. A greenhouse pot experiment was conducted to determine if inoculation with vesicular-arbuscular mycorrhizal (VAM) fungi will enhance vegetation establishment on abandoned coal fly ash basinss, Spores of Glomus intraradices (Schenck and Smith) and Glomus etunicatum (Becker and Gerdemann) were added to weathered precipitator ash (EC-0.91 dSm[sup -1], pH 5.0) and to a pasteurized soils of the same pH (Grossarenic Paleudult, 92% sand, 1% organic matter). Some soil and ash were left unamended as non-mycorrhizal controls. Cucumber (Cucumis sativus L. cv. Poinsette 76) seeds were sown, watered regularly, and fertilized periodically with macronutrient solution. By 8 weeks all ash-grown plants exhibited smaller leaves with leaf margin curl and necrosis, and plant biomass was significantly less (0.75x) than soil-grown plants. Based on analysis of 18 elements in plant tissues, toxicity to B, Mn, or Zn could have caused growth suppression, confirming trace element problems for plant growth on fly ash. For plants grown on fly ash, G. etunicatum was the only fungus that colonized roots (20% of root length reduced from 67% on soil) and it suppressed plant growth to 0.80 x that of uninoculated ash-grown plants. Correspondingly, shoot Zn concentration in G. etunicatum-inoculated plants was 3.5 x higher than in uninoculated plants and at generally toxic levels (273 mg kg[sup -1]). Glomus etunicatum had no other significant effects on elemental concentrations. These results indicate that VAM colonization in acid, weathered fly ash suppressed plant growth by facilitating uptake of Zn to toxic levels, and implies a limitation to successful use of VAM for vegetation establishment on abandoned coal fly ash basins.

  7. Classroom Modified Split-Root Technique and Its Application in a Plant Habitat Selection Experiment at the College Level

    Science.gov (United States)

    Elliott, Shannon S.; Winter, Peggy A.

    2011-01-01

    The split-root technique produces a plant with two equal root masses. Traditionally, the two root masses of the single plant are cultivated in adjacent pots with or without roots from competitors for the purpose of elucidating habitat preferences. We have tailored this technology for the classroom, adjusting protocols to match resources and time…

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

    International Nuclear Information System (INIS)

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

    1990-01-01

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

  9. Split-root systems applied to the study of the legume-rhizobial symbiosis: what have we learned?

    Science.gov (United States)

    Larrainzar, Estíbaliz; Gil-Quintana, Erena; Arrese-Igor, Cesar; González, Esther M; Marino, Daniel

    2014-12-01

    Split-root system (SRS) approaches allow the differential treatment of separate and independent root systems, while sharing a common aerial part. As such, SRS is a useful tool for the discrimination of systemic (shoot origin) versus local (root/nodule origin) regulation mechanisms. This type of approach is particularly useful when studying the complex regulatory mechanisms governing the symbiosis established between legumes and Rhizobium bacteria. The current work provides an overview of the main insights gained from the application of SRS approaches to understand how nodule number (nodulation autoregulation) and nitrogen fixation are controlled both under non-stressful conditions and in response to a variety of stresses. Nodule number appears to be mainly controlled at the systemic level through a signal which is produced by nodule/root tissue, translocated to the shoot, and transmitted back to the root system, involving shoot Leu-rich repeat receptor-like kinases. In contrast, both local and systemic mechanisms have been shown to operate for the regulation of nitrogenase activity in nodules. Under drought and heavy metal stress, the regulation is mostly local, whereas the application of exogenous nitrogen seems to exert a regulation of nitrogen fixation both at the local and systemic levels. © 2014 Institute of Botany, Chinese Academy of Sciences.

  10. Interaction of Vesicular-arbuscular Mycorrhizal Fungi and Phosphorus with Meloidogyne incognita on Tomato.

    Science.gov (United States)

    Cason, K M; Hussey, R S; Roncadori, R W

    1983-07-01

    The influence of two vesicular-arbuscular mycorrhizal fungi and phosphorus (P) nutrition on penetration, development, and reproduction by Meloidogyne incognita on Walter tomato was studied in the greenhouse. Inoculation with either Gigaspora margarita or Glomus mosseae 2 wk prior to nematode inoculation did not alter infection by M. incognita compared with nonmycorrhizal plants, regardless of soil P level (either 3 mug [low P] or 30 mug [high P] available P/g soil). At a given soil P level, nematode penetration and reproduction did not differ in mycorrhizal and nonmycorrhizal plants. However, plants grown in high P soil had greater root weights, increased nematode penetration and egg production per plant, and decreased colonization by mycorrhizal fungi, compared with plants grown in low P soil. The number of eggs per female nematode on mycorrhizal and nonmycorrhizal plants was not influenced by P treatment. Tomato plants with split root systems grown in double-compartment containers which had either low P soil in both sides or high P in one side and low P in the other, were inoculated at transplanting with G. margarita and 2 wk later one-half of the split root system of each plant was inoculated with M. incognita larvae. Although the mycoorhizal fungus increased the inorganic P content of the root to a level comparable to that in plants grown in high P soil, nematode penetration and reproduction were not altered. In a third series of experiments, the rate of nematode development was not influenced by either the presence of G. margarita or high soil P, compared with control plants grown in low P soil. These data indicate that supplemental P (30 mu/g soil) alters root-knot nematode infection of tomato more than G. mosseae and G. margarita.

  11. Mycorrhizal symbiosis increases growth, reproduction and recruitment of Abutilon theophrasti Medic. in the field.

    Science.gov (United States)

    Stanley, Margot R; Koide, Roger T; Shumway, Durland L

    1993-05-01

    We examined in the field the effect of the vesicular-arbuscular (VA) mycorhizal symbiosis on the reproductive success of Abutilon theophrasti Medic., an early successional annual member of the Malvaceae. Mycorrhizal infection greatly enhanced vegetative growth, and flower, fruit and seed production, resulting in significantly greater recruitment the following year. In addition, the seeds produced by mycorrhizal plants were significantly larger and contained significantly more phosphorus than seeds from non-mycorrhizal plants, an effect which may improve offspring vigor. Infection by mycorrhizal fungi may thus contribute to the overall fitness of a host plant and strongly influence long-term plant population dynamics.

  12. EFFECTS OF VARIOUS SOIL ENVIRONMENTAL STRESSES ON THE OCCURRENCE, DISTRIBUTION AND EFFECTIVENESS OF VA MYCORRHIZAE

    Directory of Open Access Journals (Sweden)

    A.G. KHAN

    1995-01-01

    Full Text Available The vesicular - arbuscular (VA mycorrhizal fungi are geographically ubiquitous soil inhabitants and form universal symbiotic relationship with plants from every phylum. These fungi link host plants with host soils and their biota in the mycorrhizosphere and play an important role in plant health, productivity and soil structure. Although VA mycorrhizal fungi do not show any host specificity, there is increasing evidence that various climatic and edaphic environmental factors such as land use and management practices, physical, chemical and biological properties of host soils and host plant characteristics influence their occurrence, taxonomic distribution and effectiveness. The interaction of these factors with vesicular-arbuscular mycorrhizae (VAM is poorly understood except in a few cases. It is now very clear that VA mycorrhizal associations are ecologically significant factors that require more attention than previously accorded. This paper discusses the occurrence, distribution and significance of VAM in environmentally stressed soil conditions that limit plant growth such as drought, waterlogging and salinity.

  13. Interactions of Vesicular-Arbuscular Mycorrhizal Fungi, Phosphorus, and Heterodera glycines on Soybean.

    Science.gov (United States)

    Tylka, G L; Hussey, R S; Roncadori, R W

    1991-01-01

    Effects of vesicular-arbuscular mycorrhizal (VAM) fungi and soil phosphorus (P) fertility on parasitism of soybean cultivars Bragg and Wright by soybean cyst nematode (SCN) were investigated in field micropiot and greenhouse experiments. VAM fungi increased height of both cultivars and yield of Wright in microplot studies in 1986 and 1987. Conversely, yield of mycorrhizal and nonmycorrhizal plants of both cultivars was suppressed by SCN. Soil population densities of SCN were unaffected by VAM fungi in 1986 but were greater in microplots infested with VAM fungi than in control microplots in 1987. Growth of Wright soybean was stimulated by VAM fungi and suppressed by SCN in greenhouse experiments. The effect of VAM fungi on SCN varied with time. Numbers of SCN in roots and soil were decreased by VAM fungi by as much as 73% at the highest SCN inoculum level through 49 days after planting. Later, however, SCN numbers were usually comparable on mycorrhizal and nonmycorrhizal plants. Soil P fertility generally had no effect on SCN. Results of a split-root experiment indicated that VAM fungal suppression of SCN was not systemic.

  14. OneVA Pharmacy

    Data.gov (United States)

    Department of Veterans Affairs — The OneVA Pharmacy application design consists of 3 main components: VistA Medication Profile screen, Health Data Record Clinical Data Service (HDR/CDS), and OneVA...

  15. [Effect of vesicular-arbuscular mycorrhizal fungi on growth, nutrient uptake and synthesis of volatile oil in Schizonepeta tenuifolia briq].

    Science.gov (United States)

    Wei, G; Wang, H

    1991-03-01

    Inoculating Schizonepeta tenuifolia with VA mycorrhizal fungi can significantly improve the plant growth and uptake of P and S, and influence the absorption of K, Na, Fe, Mo, Mn, Zn, Co, Ba, Ni and Pb. It is interesting to note that VA mycorrhiza can also increase the synthesis of volatile oil in the shoots of S. tenuifolia. The efficiency of VA mycorrhiza varies with the fungal species.

  16. Quantification of water uptake by arbuscular mycorrhizal hyphae and its significance for leaf growth, water relations, and gas exchange of barley subjected to drought stress.

    Science.gov (United States)

    Khalvati, M A; Hu, Y; Mozafar, A; Schmidhalter, U

    2005-11-01

    Arbuscular mycorrhizal fungi alleviate drought stress in their host plants via the direct uptake and transfer of water and nutrients through the fungal hyphae to the host plants. To quantify the contribution of the hyphae to plant water uptake, a new split-root hyphae system was designed and employed on barley grown in loamy soil inoculated with Glomus intraradices under well-watered and drought conditions in a growth chamber with a 14-h light period and a constant temperature (15 degrees C; day/night). Drought conditions were initiated 21 days after sowing, with a total of eight 7-day drying cycles applied. Leaf water relations, net photosynthesis rates, and stomatal conductance were measured at the end of each drying cycle. Plants were harvested 90 days after sowing. Compared to the control treatment, the leaf elongation rate and the dry weight of the shoots and roots were reduced in all plants under drought conditions. However, drought resistance was comparatively increased in the mycorrhizal host plants, which suffered smaller decreases in leaf elongation, net photosynthetic rate, stomatal conductance, and turgor pressure compared to the non-mycorrhizal plants. Quantification of the contribution of the arbuscular mycorrhizal hyphae to root water uptake showed that, compared to the non-mycorrhizal treatment, 4 % of water in the hyphal compartment was transferred to the root compartment through the arbuscular mycorrhizal hyphae under drought conditions. This indicates that there is indeed transport of water by the arbuscular mycorrhizal hyphae under drought conditions. Although only a small amount of water transport from the hyphal compartment was detected, the much higher hyphal density found in the root compartment than in the hyphal compartment suggests that a larger amount of water uptake by the arbuscular mycorrhizal hyphae may occur in the root compartment.

  17. A phosphate transporter from the mycorrhizal fungus Glomus versiforme.

    Science.gov (United States)

    Harrison, M J; van Buuren, M L

    1995-12-07

    Vesicular-arbuscular (VA) mycorrhizal fungi form symbiotic associations with the roots of most terrestrial plants, including many agriculturally important crop species. The fungi colonize the cortex of the root to obtain carbon from their plant host, while assisting the plant with the uptake of phosphate and other mineral nutrients from the soil. This association is beneficial to the plant, because phosphate is essential for plant growth and development, especially during growth under nutrient-limiting conditions. Molecular genetic studies of these fungi and their interaction with plants have been limited owing to the obligate symbiotic nature of the VA fungi, so the molecular mechanisms underlying fungal-mediated uptake and translocation of phosphate from the soil to the plant remain unknown. Here we begin to investigate this process by identifying a complementary DNA that encodes a transmembrane phosphate transporter (GvPT) from Glomus versiforme, a VA mycorrhizal fungus. The function of the protein encoded by GvPT was confirmed by complementation of a yeast phosphate transport mutant. Expression of GvPT was localized to the external hyphae of G. versiforme during mycorrhizal associations, these being the initial site of phosphate uptake from the soil.

  18. Effects of PEG-Induced Water Deficit in Solanum nigrum on Zn and Ni Uptake and Translocation in Split Root Systems

    Directory of Open Access Journals (Sweden)

    Urs Feller

    2015-06-01

    Full Text Available Drought strongly influences root activities in crop plants and weeds. This paper is focused on the performance of the heavy metal accumulator Solanum nigrum, a plant which might be helpful for phytoremediation. The water potential in a split root system was decreased by the addition of polyethylene glycol (PEG 6000. Rubidium, strontium and radionuclides of heavy metals were used as markers to investigate the uptake into roots, the release to the shoot via the xylem, and finally the basipetal transport via the phloem to unlabeled roots. The uptake into the roots (total contents in the plant was for most makers more severely decreased than the transport to the shoot or the export from the shoot to the unlabeled roots via the phloem. Regardless of the water potential in the labeling solution, 63Ni and 65Zn were selectively redistributed within the plant. From autoradiographs, it became evident that 65Zn accumulated in root tips, in the apical shoot meristem and in axillary buds, while 63Ni accumulated in young expanded leaves and roots but not in the meristems. Since both radionuclides are mobile in the phloem and are, therefore, well redistributed within the plant, the unequal transfer to shoot and root apical meristems is most likely caused by differences in the cell-to-cell transport in differentiation zones without functional phloem (immature sieve tubes.

  19. Does origin of mycorrhizal fungus on mycorrhizal plant influence effectiveness of the mycorrhizal symbiosis?

    NARCIS (Netherlands)

    Heijden, van der E.W.; Kuyper, T.W.

    2001-01-01

    Mycorrhizal effectiveness depends on the compatibility between fungus and plant. Therefore, genetic variation in plant and fungal species affect the effectiveness of the symbiosis. The importance of mycorrhizal plant and mycorrhizal fungus origin was investigated in two experiments. In the first

  20. Inoculation of fumigated nursery beds and containers with arbuscular mycorrhizal products for eastern redcedar production

    Science.gov (United States)

    Michelle M. Cram; Stephen W. Fraedrich

    2015-01-01

    Commercially available arbuscular mycorrhizal (AM) products were applied at an operational rate to eastern redcedar (Juniperus virginiana L.) nursery beds and containers to evaluate seedling growth and colonization responses. A field study at the Augusta Forestry Center in Crimora, VA, and a companion container study were initiated in the fall of 2012. MycoApply® Endo...

  1. The decrease in the population of Gluconacetobacter diazotrophicus in sugarcane after nitrogen fertilization is related to plant physiology in split root experiments.

    Science.gov (United States)

    Rodríguez-Andrade, Osvaldo; Fuentes-Ramírez, Luis E; Morales-García, Yolanda E; Molina-Romero, Dalia; Bustillos-Cristales, María R; Martínez-Contreras, Rebeca D; Muñoz-Rojas, Jesús

    2015-01-01

    It has been established that a decrease in the population of Gluconacetobacter diazotrophicus associated with sugarcane occurs after nitrogen fertilization. This fact could be due to a direct influence of NH(4)NO(3) on bacterial cells or to changes in plant physiology after fertilizer addition, affecting bacterial establishment. In this work, we observed that survival of G. diazotrophicus was directly influenced when 44.8mM of NH(4)NO(3) (640mgN/plant) was used for in vitro experiments. Furthermore, micropropagated sugarcane plantlets were inoculated with G. diazotrophicus and used for split root experiments, in which both ends of the system were fertilized with a basal level of NH(4)NO(3) (0.35mM; 10mgN/plant). Twenty days post inoculation (dpi) one half of the plants were fertilized with a high dose of NH(4)NO(3) (6.3mM; 180 mgN/plant) on one end of the system. This nitrogen level was lower than that directly affecting G. diazotrophicus cells; however, it caused a decrease in the bacterial population in comparison with control plants fertilized with basal nitrogen levels. The decrease in the population of G. diazotrophicus was higher in pots fertilized with a basal nitrogen level when compared with the corresponding end supplied with high levels of NH4NO3 (100dpi; 80 days post fertilization) of the same plant system. These observations suggest that the high nitrogen level added to the plants induce systemic physiological changes that affect the establishment of G. diazotrophicus. Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  2. Induction of fungal disease resistance in Vicia faba by dual inoculation with Rhizobium leguminosarum and vesicular-arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Rabie, G H

    1998-01-01

    Infection of Vicia faba with Bothytis fabae causes significant decreases in growth vigour, total nitrogen content, number of nodules and nutrient accumulation. Na-uptake and phenolics concentration increased compared to that of noninfected plants. In contrast, dual inoculation of Rhizobium and VA mycorrhizae increased all above parameters suggesting a distinct improvement of the plants. The results also revealed that an inverse correlation may exist between phenolic, calcium, magnesium and zinc concentrations in mycorrhizal plant tissues grown in presence of rhizobial bacteria and the disease severity. From these findings we conclude a possible role of both VA mycorrhizal fungi and rhizobial bacteria in the decrease of susceptibility of plants.

  3. Impact of Wood Biochar and Its Interactions with Mycorrhizal Fungi, Phosphorus Fertilization and Irrigation Strategies on Potato Growth

    DEFF Research Database (Denmark)

    Liu, C.; Liu, F.; Ravnskov, S.

    2017-01-01

    Biochar amendment to soil has the potential to improve soil quality and increase crop yield. Arbuscular mycorrhizal fungi (AMF) provide beneficial plant services of stress alleviation with respect to phosphorus (P) deficiency and drought. The aim of this study was to explore interactive effects...... of biochar with AMF, P fertilization levels and irrigation strategies on growth of potato plants. Potato plants were amended with wood biochar of 0.74 % w/w (B+) or not (B−), fertilized with phosphorus of 0.11 mg P g−1 soil (P1) or not (P0), irrigated with full irrigation (FI) or partial root-zone drying...... irrigation (PRD) and inoculated with AMF of Rhizophagus irregularis (M+) or not (M−) in split-root pots in a sandy loam soil. Plants were analysed for growth performance, P and nitrogen (N) uptake and water use efficiency (WUE). Biochar adsorption of mineral P and N in aqueous solution was tested...

  4. Initial vesicular-arbuscular mycorrhizal development of slender wheatgrass on two amended mine spoils

    Energy Technology Data Exchange (ETDEWEB)

    Zak, J.C.; Parkinson, D. (University of Calgary, Calgary, AB (Canada). Dept. of Biology)

    1982-01-01

    The initial vesicular-arbuscular (VA) mycorrhizal development of slender wheatgrass on extracted oil-sands and subalpine coal-mine spoils, amended with either fertilizer, peat, or liquid sewage sludge, was examined. Plants were sampled at 2,6 and 10 weeks after plant emergence and the level of infection was expressed as length of mycorrhizal root per plant and length of root which contained arbuscules, vesicles, or only hyphae. Mycorrhizal infection of slender wheatgrass on the oil sands was limited to plants on the peat-amended spoil. Infection of plants on the peat-amended oil-sands spoil was detected by 2 weeks. Plants on the subalpine spoil were infected at 2 weeks only on the peat-amended spoil. While slender wheatgrass on the control and fertilizer-amended spoil developed mycorrhizae by 6 weeks, infection was not observed in plants on the sewage-amended spoil until 10 weeks. At 10 weeks, there were no significant differences in lengths of mycorrhizal root per plant among the amendments. Increased P levels in the fertilizer- and sewage-amended subalpine spoil did not suppress VA mycorrhizal development. 43 refs., 6 tabs.

  5. Feasibility of Using Mycorrhizal Fungi for Enhancement of Plant Establishment on Dredged Material Disposal Sites. A Literature Review.

    Science.gov (United States)

    1986-06-01

    Alfalfa Lambert et al. (1980c); 0’Bannon et al. (1980); Owusu- Bennoah and Mosse (1979) (Continued) 48 Scientific Name Common Name Source Persea americana...with VA Mycorrhizal Fungi," Annual Meeting of the Pacific Division of the American Phytopathologi- cal Society, Phytopathology, Vol 73, No. 6, pp 956...Mycorrhizae and Plant Disease Research, The American Phytopathological Society, Vol 72, No. 8, pp 1108-1114. Carling, D. E., et al. 1979. "Colonization

  6. VA National Bed Control System

    Data.gov (United States)

    Department of Veterans Affairs — The VA National Bed Control System records the levels of operating, unavailable and authorized beds at each VAMC, and it tracks requests for changes in these levels....

  7. The Geometric-VaR Backtesting Method

    DEFF Research Database (Denmark)

    Wei, Wei; Pelletier, Denis

    2014-01-01

    This paper develops a new test to evaluate Value af Risk (VaR) forecasts. VaR is a standard risk measure widely utilized by financial institutions and regulators, yet estimating VaR is a challenging problem, and popular VaR forecast relies on unrealistic assumptions. Hence, assessing...

  8. Partner selection in the mycorrhizal mutualism

    NARCIS (Netherlands)

    Werner, G.D.A.; Kiers, E.T.

    2015-01-01

    Partner selection in the mycorrhizal symbiosis is thought to be a key factor stabilising the mutualism. Both plant hosts and mycorrhizal fungi have been shown to preferentially allocate resources to higher quality partners. This can help maintain underground cooperation, although it is likely that

  9. Resistance Responses of Potato to Vesicular-Arbuscular Mycorrhizal Fungi under Varying Abiotic Phosphorus Levels.

    Science.gov (United States)

    McArthur, D A; Knowles, N R

    1992-09-01

    In mycorrhizal symbioses, susceptibility of a host plant to infection by fungi is influenced by environmental factors, especially the availability of soil phosphorus. This study describes morphological and biochemical details of interactions between a vesicular-arbuscular mycorrhizal (VAM) fungus and potato (Solanum tuberosum L. cv Russet Burbank) plants, with a particular focus on the physiological basis for P-induced resistance of roots to infection. Root infection by the VAM fungus Glomus fasciculatum ([Thaxt. sensu Gerdemann] Gerdemann and Trappe) was extensive for plants grown with low abiotic P supply, and plant biomass accumulation was enhanced by the symbiosis. The capacity of excised roots from P-deficient plants to produce ethylene in the presence or absence of exogenous 1-amino cyclopropane-1-carboxylic acid (ACC) was markedly reduced by VAM infection. This apparent inhibition of ACC oxidase (ACC(ox)) activity was localized to areas containing infected roots, as demonstrated in split-root studies. Furthermore, leachate from VAM roots contained a potent water-soluble inhibitor of ethylene generation from exogenous ACC by nonmycorrhizal (NM) roots. The leachate from VAM-infected roots had a higher concentration of phenolics, relative to that from NM roots. Moreover, the rates of ethylene formation and phenolic concentration in leachates from VAM roots were inversely correlated, suggesting that this inhibitor may be of a phenolic nature. The specific activity of extracellular peroxidase recovered in root leachates was not stimulated by VAM infection, although activity on a fresh weight basis was significantly enhanced, reflecting the fact that VAM roots had higher protein content than NM roots. Polyphenol oxidase activity of roots did not differ between NM and VAM roots. These results characterize the low resistance response of P-deficient plants to VAM infection. When plants were grown with higher abiotic P supply, the relative benefit of the VAM symbiosis

  10. Phylogeonomics and Ecogenomics of the Mycorrhizal Symbiosis

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Alan; Grigoriev, Igor V.; Kohler, Annegret; Martin, Francis

    2013-05-23

    Mycorrhizal fungi play critical roles in host plant health, soil community structure and chemistry, and carbon and nutrient cycling, all areas of intense interest to the US Dept. of Energy (DOE) Joint Genome Institute (JGI). To this end we are building on our earlier sequencing of the Laccaria bicolor genome by partnering with INRA-Nancy and the mycorrhizal research community in the MGI to sequence and analyze 2 dozen mycorrhizal genomes of numerous known mycorrhizal orders and several ecological types (ectomycorrhizal [ECM], ericoid, orchid, and arbuscular). JGI has developed and deployed high-throughput pipelines for genomic, transcriptomic, and re-sequencing, and platforms for assembly, annotation, and analysis. In the last 2 years we have sequenced 21 genomes of mycorrhizal fungi, and resequenced 6 additional strains of L. bicolor. Most of this data is publicly available on JGI MycoCosm?s Mycorrhizal Fungi Portal (http://jgi.doe.gov/Mycorrhizal_fungi/), which provides access to both the genome data and tools with which to analyze the data. These data allow us to address long-standing issues in mycorrhizal evolution and ecology. For example, a major observation of mycorrhizal evolution is that each of the major ecological types appears to have evolved independently in multiple fungal clades. Using an ecogenomic approach we provide preliminary evidence that 2 clades (Cantharellales and Sebacinales) of a single symbiotic ecotype (orchid) utilize some common regulatory (protein tyrosine kinase) and metabolic (lipase) paths, the latter of which may be the product of HGT. Using a phylogenomic approach we provide preliminary evidence that a particular ecotype (ericoid) may have evolved more than once within a major clade (Leotiomycetes).

  11. Report of VA Medical Training Programs

    Data.gov (United States)

    Department of Veterans Affairs — The Report of VA Medical Training Programs Database is used to track medical center health services trainees and VA physicians serving as faculty. The database also...

  12. Non-VA Hospital System (NVH)

    Data.gov (United States)

    Department of Veterans Affairs — The Veterans Health Administration (VHA) pays for care provided to VA beneficiaries in non-VA hospitals through its contract hospitalization program as mandated by...

  13. Mycorrhizal dependency of laurel (Ocotea sp.)

    International Nuclear Information System (INIS)

    Sierra-Escobar, Jorge A; Castro Restrepo, Dagoberto; Osorio Vega, Walter

    2009-01-01

    A greenhouse experiment was carried out to determine the mycorrhizal dependency of laurel (>Ocotea sp.). In order to do this, a completely randomized experimental design was used, with six treatments in a factorial array of 3 x 2 and five repetitions. The treatments involved a combination of three Phosphorus (P) levels in soil solution (0.002, 0.02 and 0.2 mg L-1) and two levels of mycorrhizal inoculation, either inoculated or non-inoculated with Glomus aggregatum Schenck and Smith. The leaf P content as a function of time was used as an output variable. Shoot dry matter, shoot P content, mycorrhizal colonization of roots, and mycorrhizal dependence were measured at harvest. The results indicated that the leaf P content increased significantly when using the mycorrhizal inoculation in laurel at P level 0.2 mg L -1, but not in the other P levels, on some of the sampling days. Shoot dry weight and total plant P content did not increase at all levels of soil available P. Mycorrhizal dependency of laurel reached 28%, which allows this species to be classified as moderately dependent on mycorrhiza.

  14. Diversity and classification of mycorrhizal associations.

    Science.gov (United States)

    Brundrett, Mark

    2004-08-01

    Most mycorrhizas are 'balanced' mutualistic associations in which the fungus and plant exchange commodities required for their growth and survival. Myco-heterotrophic plants have 'exploitative' mycorrhizas where transfer processes apparently benefit only plants. Exploitative associations are symbiotic (in the broad sense), but are not mutualistic. A new definition of mycorrhizas that encompasses all types of these associations while excluding other plant-fungus interactions is provided. This definition recognises the importance of nutrient transfer at an interface resulting from synchronised plant-fungus development. The diversity of interactions between mycorrhizal fungi and plants is considered. Mycorrhizal fungi also function as endophytes, necrotrophs and antagonists of host or non-host plants, with roles that vary during the lifespan of their associations. It is recommended that mycorrhizal associations are defined and classified primarily by anatomical criteria regulated by the host plant. A revised classification scheme for types and categories of mycorrhizal associations defined by these criteria is proposed. The main categories of vesicular-arbuscular mycorrhizal associations (VAM) are 'linear' or 'coiling', and of ectomycorrhizal associations (ECM) are 'epidermal' or 'cortical'. Subcategories of coiling VAM and epidermal ECM occur in certain host plants. Fungus-controlled features result in 'morphotypes' within categories of VAM and ECM. Arbutoid and monotropoid associations should be considered subcategories of epidermal ECM and ectendomycorrhizas should be relegated to an ECM morphotype. Both arbuscules and vesicles define mycorrhizas formed by glomeromycotan fungi. A new classification scheme for categories, subcategories and morphotypes of mycorrhizal associations is provided.

  15. Comparison of outcomes for veterans receiving dialysis care from VA and non-VA providers

    Directory of Open Access Journals (Sweden)

    Wang Virginia

    2013-01-01

    Full Text Available Abstract Background Demand for dialysis treatment exceeds its supply within the Veterans Health Administration (VA, requiring VA to outsource dialysis care by purchasing private sector dialysis for veterans on a fee-for-service basis. It is unclear whether outcomes are similar for veterans receiving dialysis from VA versus non-VA providers. We assessed the extent of chronic dialysis treatment utilization and differences in all-cause hospitalizations and mortality between veterans receiving dialysis from VA versus VA-outsourced providers. Methods We constructed a retrospective cohort of veterans in 2 VA regions who received chronic dialysis treatment financed by VA between January 2007 and December 2008. From VA administrative data, we identified veterans who received outpatient dialysis in (1 VA, (2 VA-outsourced settings, or (3 both (“dual” settings. In adjusted analyses, we used two-part and logistic regression to examine associations between dialysis setting and all-cause hospitalization and mortality one-year from veterans’ baseline dialysis date. Results Of 1,388 veterans, 27% received dialysis exclusively in VA, 47% in VA-outsourced settings, and 25% in dual settings. Overall, half (48% were hospitalized and 12% died. In adjusted analysis, veterans in VA-outsourced settings incurred fewer hospitalizations and shorter hospital stays than users of VA due to favorable selection. Dual-system dialysis patients had lower one-year mortality than veterans receiving VA dialysis. Conclusions VA expenditures for “buying” outsourced dialysis are high and increasing relative to “making” dialysis treatment within its own system. Outcomes comparisons inform future make-or-buy decisions and suggest the need for VA to consider veterans’ access to care, long-term VA savings, and optimal patient outcomes in its placement decisions for dialysis services.

  16. Comparison of outcomes for veterans receiving dialysis care from VA and non-VA providers.

    Science.gov (United States)

    Wang, Virginia; Maciejewski, Matthew L; Patel, Uptal D; Stechuchak, Karen M; Hynes, Denise M; Weinberger, Morris

    2013-01-18

    Demand for dialysis treatment exceeds its supply within the Veterans Health Administration (VA), requiring VA to outsource dialysis care by purchasing private sector dialysis for veterans on a fee-for-service basis. It is unclear whether outcomes are similar for veterans receiving dialysis from VA versus non-VA providers. We assessed the extent of chronic dialysis treatment utilization and differences in all-cause hospitalizations and mortality between veterans receiving dialysis from VA versus VA-outsourced providers. We constructed a retrospective cohort of veterans in 2 VA regions who received chronic dialysis treatment financed by VA between January 2007 and December 2008. From VA administrative data, we identified veterans who received outpatient dialysis in (1) VA, (2) VA-outsourced settings, or (3) both ("dual") settings. In adjusted analyses, we used two-part and logistic regression to examine associations between dialysis setting and all-cause hospitalization and mortality one-year from veterans' baseline dialysis date. Of 1,388 veterans, 27% received dialysis exclusively in VA, 47% in VA-outsourced settings, and 25% in dual settings. Overall, half (48%) were hospitalized and 12% died. In adjusted analysis, veterans in VA-outsourced settings incurred fewer hospitalizations and shorter hospital stays than users of VA due to favorable selection. Dual-system dialysis patients had lower one-year mortality than veterans receiving VA dialysis. VA expenditures for "buying" outsourced dialysis are high and increasing relative to "making" dialysis treatment within its own system. Outcomes comparisons inform future make-or-buy decisions and suggest the need for VA to consider veterans' access to care, long-term VA savings, and optimal patient outcomes in its placement decisions for dialysis services.

  17. Systemic and local regulation of phosphate and nitrogen transporter genes by arbuscular mycorrhizal fungi in roots of winter wheat (Triticum aestivum L.).

    Science.gov (United States)

    Duan, Jianfeng; Tian, Hui; Drijber, Rhae A; Gao, Yajun

    2015-11-01

    Previous studies have reported that the expression of phosphate (Pi) or nitrogen (N) transporter genes in roots of plants could be regulated by arbuscular mycorrhizal (AM) fungi, but little is known whether the regulation is systemic or not. The present study investigated the systemic and local regulation of multiple phosphate and nitrogen transporter genes by four AM fungal species belonging to four genera in the roots of winter wheat. A split-root culture system with AM inoculated (MR) and non-inoculated root compartments (NR) was used to investigate the systemic or local responses of phosphate and nitrogen transporter genes to colonization by four AM fungi in the roots of wheat. The expression of four Pi transporter, five nitrate transporter, and three ammonium transporter genes was quantified using real-time PCR. Of the four AM fungi tested, all locally increased expression of the AM-inducible Pi transporter genes, and most locally decreased expression of a Pi-starvation inducible Pi transporter gene. The addition of N in soil increased the expression of either Pi starvation inducible Pi transporters or AM inducible Pi transporters. Inoculation with AM fungi either had no effect, or could locally or systemically down-regulate expression of nitrogen transporter genes depending on gene type and AM fungal species. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  18. Frost hardiness of mycorrhizal and non-mycorrhizal Scots pine under two fertilization treatments.

    Science.gov (United States)

    Korhonen, Anna; Lehto, Tarja; Repo, Tapani

    2015-07-01

    Survival and functioning of mycorrhizal associations at low temperatures are not known well. In an earlier study, ectomycorrhizas did not affect the frost hardiness of Scots pine (Pinus sylvestris L.) roots, but here we studied whether differential nutrient availability would change the result and additionally, alter frost hardiness aboveground. The aim in this experiment was to compare the frost hardiness of roots and needles of mycorrhizal (Hebeloma sp.) and non-mycorrhizal Scots pine seedlings raised using two fertilization treatments and two cold-hardening regimes. The fertilization treatments were low (LF) and high (HF) application of a complete nutrient solution. Three hundred mycorrhizal and non-mycorrhizal seedlings were cultivated in growth chambers in four blocks for 16 weeks. For the first 9 weeks, the seedlings grew in long-day and high-temperature (LDHT) with low fertilization and then they were raised for 3 weeks in LDHT with either low or high fertilization. After this, half of the plants in each treatment combination remained in LDHT, and half were transferred to short-day and low-temperature (SDLT) conditions to cold acclimatize. The frost hardiness of the roots and needles was assessed using controlled freezing tests followed by electrolyte leakage tests (REL). Mycorrhizal roots were slightly more frost hardy than non-mycorrhizal roots, but only in the growing-season conditions (LDHT) in low-nutrient treatment. In LDHT and LF, the frost hardiness of the non-mycorrhizal roots was about -9 °C, and that of the non-mycorrhizal HF roots and the mycorrhizal roots in both fertilization levels was about -11 °C. However, no difference was found in the roots within the SDLT regime, and in needles, there was no difference between mycorrhizal and fertilization treatments. The frost hardiness of needles increased by SDLT treatment, being -8.5 and -14.1 °C in LDHT and SDLT, respectively. The dry mass of roots, stems, and needles was lower in LF than in

  19. Arbuscular mycorrhizal fungi increase salt tolerance of apple seedlings.

    Science.gov (United States)

    Yang, Shou-Jun; Zhang, Zhong-Lan; Xue, Yuan-Xia; Zhang, Zhi-Fen; Shi, Shu-Yi

    2014-12-01

    Apple trees are often subject to severe salt stress in China as well as in the world that results in significant loss of apple production. Therefore this study was carried out to evaluate the response of apple seedlings inoculated with abuscular mycorrhizal fungi under 0, 2‰, 4‰ and 6‰ salinity stress levels and further to conclude the upper threshold of mycorrhizal salinity tolerance. The results shows that abuscular mycorrhizal fungi significantly increased the root length colonization of mycorrhizal apple plants with exposure time period to 0, 2‰ and 4‰ salinity levels as compared to non-mycorrhizal plants, however, percent root colonization reduced as saline stress increased. Salinity levels were found to negatively correlate with leaf relative turgidity, osmotic potential irrespective of non-mycorrhizal and mycorrhizal apple plants, but the decreased mycorrhizal leaf turgidity maintained relative normal values at 2‰ and 4‰ salt concentrations. Under salt stress condition, Cl - and Na + concentrations clearly increased and K + contents obviously decreased in non-mycorrhizal roots in comparison to mycorrhizal plants, this caused mycorrhizal plants had a relatively higher K + /Na + ratio in root. In contrast to zero salinity level, although ascorbate peroxidase and catalase activities in non-inoculated and inoculated leaf improved under all saline levels, the extent of which these enzymes increased was greater in mycorrhizal than in non-mycorrhizal plants. The numbers of survived tree with non-mycorrhization were 40, 20 and 0 (i.e., 66.7%, 33.3% and 0) on the days of 30, 60 and 90 under 4‰ salinity, similarly in mycorrhization under 6‰ salinity 40, 30 and 0 (i.e., 66.7%, 50% and 0) respectively. These results suggest that 2‰ and 4‰ salt concentrations may be the upper thresholds of salinity tolerance in non-mycorrhizal and mycorrhizal apple plants, respectively.

  20. Frost hardiness of mycorrhizal (Hebeloma sp.) and non-mycorrhizal Scots pine roots.

    Science.gov (United States)

    Korhonen, Anna; Lehto, Tarja; Repo, Tapani

    2013-10-01

    The frost hardiness (FH) of mycorrhizal [ectomycorrhizal (ECM)] and non-mycorrhizal (NM) Scots pine (Pinus sylvestris) seedlings was studied to assess whether mycorrhizal symbiosis affected the roots' tolerance of below-zero temperatures. ECM (Hebeloma sp.) and NM seedlings were cultivated in a growth chamber for 18 weeks. After 13 weeks' growth in long-day and high-temperature (LDHT) conditions, a half of the ECM and NM seedlings were moved into a chamber with short-day and low-temperature (SDLT) conditions to cold acclimate. After exposures to a range of below-zero temperatures, the FH of the roots was assessed by means of the relative electrolyte leakage test. The FH was determined as the inflection point of the temperature-response curve. No significant difference was found between the FH of mycorrhizal and non-mycorrhizal roots in LDHT (-8.9 and -9.8 °C) or SDLT (-7.5 and -6.8 °C). The mycorrhizal treatment had no significant effect on the total dry mass, the allocation of dry mass among the roots and needles or nutrient accumulation. The mycorrhizal treatment with Hebeloma sp. did not affect the FH of Scots pine in this experimental setup. More information is needed on the extent to which mycorrhizas tolerate low temperatures, especially with different nutrient contents and different mycorrhiza fungi.

  1. OneVA EA Vision and Strategy

    Data.gov (United States)

    Department of Veterans Affairs — The outcomes/goals supported by effective use of an EA are: Improved Service Delivery, Functional Integration, Resource Optimization and Authoritative Reference. VA...

  2. Geographic Distribution of VA Expenditures FY 2016

    Data.gov (United States)

    Department of Veterans Affairs — This report details VA expenditures at the state, county, and Congressional District level. It includes categories such as Compensation and Pension, Construction,...

  3. Geographic Distribution of VA Expenditures FY2010

    Data.gov (United States)

    Department of Veterans Affairs — This report details VA expenditures at the state, county, and Congressional District level. It includes categories such as Compensation and Pension, Construction,...

  4. Geographic Distribution of VA Expenditures FY2012

    Data.gov (United States)

    Department of Veterans Affairs — This report details VA expenditures at the state, county, and Congressional District level. It includes categories such as Compensation and Pension, Construction,...

  5. Geographic Distribution of VA Expenditures FY2004

    Data.gov (United States)

    Department of Veterans Affairs — This report details VA expenditures at the state, county, and Congressional District level. It includes categories such as Compensation and Pension, Construction,...

  6. Geographic Distribution of VA Expenditures FY1998

    Data.gov (United States)

    Department of Veterans Affairs — This report details VA expenditures at the state, county, and Congressional District level. It includes categories such as Compensation and Pension, Construction,...

  7. Geographic Distribution of VA Expenditures FY2009

    Data.gov (United States)

    Department of Veterans Affairs — This report details VA expenditures at the state, county, and Congressional District level. It includes categories such as Compensation and Pension, Construction,...

  8. Geographic Distribution of VA Expenditures FY2013

    Data.gov (United States)

    Department of Veterans Affairs — This report details VA expenditures at the state, county, and Congressional District level. It includes categories such as Compensation and Pension, Construction,...

  9. Geographic Distribution of VA Expenditures FY2002

    Data.gov (United States)

    Department of Veterans Affairs — This report details VA expenditures at the state, county, and Congressional District level. It includes categories such as Compensation and Pension, Construction,...

  10. Has the VA Become a White Elephant?

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2016-11-01

    Full Text Available No abstract available. Article truncated at 150 words. As I write this Dennis Wagner is publishing a series of articles in the Arizona Republic describing his quest to find out if care at VA hospitals have improved over the last 2 years (1. To begin the article Wagner describes the fable of the King of Siam who presented albino pachyderms to his enemies knowing they would be bankrupted because the cost of food and care outweighed all usefulness. A modern expression derives from this parable: the white elephant. The Department of Veterans Affairs (VA has prided itself on being a leader in healthcare. It is the largest healthcare system in the US, implemented the first electronic medical record, and more than 70 percent of all US doctors have received training in the VA healthcare system (2. This year the VA is celebrating the 70th anniversary of its partnership with US medical schools. Beginning in 1946, the VA partnered ...

  11. KENO-VA-PVM KENO-VA-SM, KENO5A for Parallel Processors

    International Nuclear Information System (INIS)

    Ramon, Javier; Pena, Jorge

    2002-01-01

    1 - Description of program or function: This package contains versions KENO-Va-SM (Shared Memory version) and KENO-Va-PVM (Parallel Virtual Machine version) based on SCALE-4.1. KENO-Va three-dimensional Boltzmann transport equation for neutron multiplying systems. The primary purpose of KENO-Va is to determine k-effective. Other calculated quantities include lifetime and generation time, energy-dependent leakages, energy- and region-dependent absorptions, fissions, fluxes, and fission densities. 2 - Method of solution: KENO-Va employs the Monte Carlo technique

  12. 75 FR 78806 - Agency Information Collection (Create Payment Request for the VA Funding Fee Payment System (VA...

    Science.gov (United States)

    2010-12-16

    ... Payment Request for the VA Funding Fee Payment System (VA FFPS); a Computer Generated Funding Fee Receipt.... 2900-0474.'' SUPPLEMENTARY INFORMATION: Title: Create Payment Request for the VA Funding Fee Payment System (VA FFPS); a Computer Generated Funding Fee Receipt, VA Form 26-8986. OMB Control Number: 2900...

  13. Interaction of arbuscular mycorrhizal fungus ( Glomus intraradices ...

    African Journals Online (AJOL)

    In this research, the effect of two arbuscular mycorrhizal fungal (AMF) inoculation (Glomus intraradices and Glomus etunicatum) on tomato plants growing in nutrient solution with high concentrations of copper were studied. Copper (Cu) is an essential micronutrient for plant growth. In the present study, the effect of copper ...

  14. Response of Arbuscular mycorrhizal fungi and Rhizobium ...

    African Journals Online (AJOL)

    The aim of the present study was to investigate the effect ofRhizobium and Arbuscular mycorrhizal fungi inoculation, both individually and in combination on growth and chlorophyll content of economically important plant Vigna unguiculata L. A significant (p < 0.05) increase over control in root length (45.6 cm), shoot height ...

  15. Technology Reference Model (TRM) Reports: VA Category Mapping Report

    Data.gov (United States)

    Department of Veterans Affairs — The One VA Enterprise Architecture (OneVA EA) is a comprehensive picture of the Department of Veterans Affairs' (VA) operations, capabilities and services and the...

  16. Technology Reference Model (TRM) Reports: VA Category Framework Count Report

    Data.gov (United States)

    Department of Veterans Affairs — The One VA Enterprise Architecture (OneVA EA) is a comprehensive picture of the Department of Veterans Affairs' (VA) operations, capabilities and services and the...

  17. Community assembly and coexistence in communities of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Vályi, Kriszta; Mardhiah, Ulfah; Rillig, Matthias C; Hempel, Stefan

    2016-10-01

    Arbuscular mycorrhizal fungi are asexual, obligately symbiotic fungi with unique morphology and genomic structure, which occupy a dual niche, that is, the soil and the host root. Consequently, the direct adoption of models for community assembly developed for other organism groups is not evident. In this paper we adapted modern coexistence and assembly theory to arbuscular mycorrhizal fungi. We review research on the elements of community assembly and coexistence of arbuscular mycorrhizal fungi, highlighting recent studies using molecular methods. By addressing several points from the individual to the community level where the application of modern community ecology terms runs into problems when arbuscular mycorrhizal fungi are concerned, we aim to account for these special circumstances from a mycocentric point of view. We suggest that hierarchical spatial structure of arbuscular mycorrhizal fungal communities should be explicitly taken into account in future studies. The conceptual framework we develop here for arbuscular mycorrhizal fungi is also adaptable for other host-associated microbial communities.

  18. Importance of mycorrhizal symbiosis for local adaptations of Aster amellus

    OpenAIRE

    Plachá, Hana

    2006-01-01

    3 Abstract The importance of arbuscular mycorrhizal (AM) symbiosis for survival and growth of many plant species is generally recognized. It has been repeatedly shown that symbiosis with mycorrhizal fungi can increase the fitness of many plant species. This increasing fitness is caused by increased uptake of phosphorus and other nutrients or pathogen protection. Most studies on mycorrhizal associations explore these types of relationship using single plant population and single fungal species...

  19. VA Veterans Health Administration Access Data

    Data.gov (United States)

    Department of Veterans Affairs — At the Department of Veterans Affairs (VA), our most important mission is to provide the high quality health care and benefits Veterans have earned and deserve —...

  20. VA Personal Health Record Sample Data

    Data.gov (United States)

    Department of Veterans Affairs — My HealtheVet (www.myhealth.va.gov) is a Personal Health Record portal designed to improve the delivery of health care services to Veterans, to promote health and...

  1. Plant Functional Traits Associated with Mycorrhizal Root Foraging in Arbuscular Mycorrhizal and Ectomycorrhizal Trees

    Science.gov (United States)

    Eissenstat, D. M.; Chen, W.; Cheng, L.; Liu, B.; Koide, R. T.; Guo, D.

    2016-12-01

    Root foraging for nutrient "hot spots" is a key strategy by which some plants maximize nutrient gain from their carbon investment in root and mycorrhizal hyphae. Foraging strategies may depend on costs of root construction, with thick roots generally costing more per unit length than thin roots. Investment in mycorrhizal hyphae, which are considerably thinner than roots, may represent an alternative strategy for cost-effective nutrient foraging, especially for thick-root species. Type of mycorrhiza may matter, as ectomycorrhizal (EM) fungi are more associated with longer hyphae and ability to mineralize organic matter than arbuscular mycorrhizal (AM) fungi. Among AM trees in both subtropical forests in SE China and in temperate forests in central Pennsylvania, USA, we found that tree species with thin roots proliferated their roots in soil patches enriched with mineral nutrients to a greater extent than species with thick roots. In addition, thick-root species were consistently colonized more heavily with mycorrhizal fungi than thin root species, although nutrient addition tended to diminish colonization. In a common garden in central Pennsylvania of both AM and EM tree species, we found that nutrient patches enriched with organic materials resulted in greater root and mycorrhizal fungal proliferation compared to those enriched with inorganic nutrients and that thick-root species proliferated more with their mycorrhizal fungi whereas thin-root species proliferated more with their roots. We further examined with many more species, patterns of root and mycorrhizal fungal proliferation in organic-nutrient-enriched patches. Foraging precision, or the extent that roots or mycorrhizal hyphae grew in the enriched patch relative to the unenriched patch, was related to both root thickness and type of mycorrhiza. In both AM and EM trees, thick-root species were not selective foragers of either their roots or hyphae. In thin-root species, there was strong selectivity in

  2. Phosphatase activity in sandy soil influenced by mycorrhizal and non-mycorrhizal cover crops

    Directory of Open Access Journals (Sweden)

    Alceu Kunze

    2011-06-01

    Full Text Available Cover crops may difffer in the way they affect rhizosphere microbiota nutrient dynamics. The purpose of this study was to evaluate the effect of mycorrhizal and non-mycorrhizal cover crops on soil phosphatase activity and its persistence in subsequent crops. A three-year experiment was carried out with a Typic Quartzipsamment. Treatments were winter species, either mycorrhizal black oat (Avena strigosa Schreb or the non-mycorrhizal species oilseed radish (Raphanus sativus L. var. oleiferus Metzg and corn spurry (Spergula arvensis L.. The control treatment consisted of resident vegetation (fallow in the winter season. In the summer, a mixture of pearl millet (Pennisetum americanum L. with sunnhemp (Crotalaria juncea L. or with soybean (Glycine max L. was sown in all plots. Soil cores (0-10 cm and root samples were collected in six growing seasons (winter and summer of each year. Microbial biomass P was determined by the fumigation-extraction method and phosphatase activity using p-nitrophenyl-phosphate as enzyme substrate. During the flowering stage of the winter cover crops, acid phosphatase activity was 30-35 % higher in soils with the non-mycorrhizal species oilseed radish, than in the control plots, regardless of the amount of P immobilized in microbial biomass. The values of enzyme activity were intermediate in the plots with corn spurry and black oat. Alkaline phosphatase activity was 10-fold lower and less sensitive to the treatments, despite the significant relationship between the two phosphatase activities. The effect of plant species on the soil enzyme profile continued in the subsequent periods, during the growth of mycorrhizal summer crops, after completion of the life cycle of the cover crops.

  3. ARBUSCULAR MYCORRHIZAL ASSOCIATION IN Coccothrinax readii Quero

    Directory of Open Access Journals (Sweden)

    Gerardo Emmanuel Polanco Hernández

    2013-08-01

    Full Text Available Coccothrinax readii, is a palm endemic to the Yucatan coast, its successful establishment in stressful environments suggests that factors such as mycorrhizal association may determine its success, the question arose in this work, assess environmental conditions which states and to describe their particular characteristics related to the anatomy of their roots and mycorrhizal colonization in three different seasons over a year. The study site was the coastal dune scrub of San Benito, Yucatan, where he placed a data logger that measurements performed ambient temperature (T, relative humidity (HR and photosynthethic photon flux (PPF for five days in dry, rainy and windy, also determined  the total phosphorus and extractable of the soil. The results indicate significant fluctuations of environmental variables throughout the year, on the other hand, the presence of the velamen on the roots of C. readii not restrict arbuscular mycorrhizal colonization. This association is affected by microenvironmental conditions, as during the dry season, when environmental conditions are unfavorable, the colonization percentage is higher than in the windy season, when microenvironmental conditions are more favorable.

  4. Influence of mycorrhizal developmental stages and plant age on rhizosphere mycoflora of Pinus kesiya (Royle

    Directory of Open Access Journals (Sweden)

    G. D. Sharma

    2014-08-01

    Full Text Available Quantitatively the population was recorded to be high around thc mycorrhizal roots. Some fungi were specific to different stages of mycorrhizal development. Rhizopus nigricans and Cunninghamella elegans were recorded at 5% mycorrhizal association stage. Fusarium sp. was found at 20% mycorrhizal association, while Mucor spp. were obtained at 60% stage. Verticillium sp. had the highest frequency of occurrence in the beginning of mycorrhizal association but later on Penicilium spp. were found to be the most common. Sugar content of mycorrhizal and nonmycorrhizal roots were determined to assess their effect on the mycorrhizospheric micropopulation. The mannitol and trehalose were present only in mycorrhizal roots.

  5. Do Older Rural and Urban Veterans Experience Different Rates of Unplanned Readmission to VA and Non-VA Hospitals?

    Science.gov (United States)

    Weeks, William B.; Lee, Richard E.; Wallace, Amy E.; West, Alan N.; Bagian, James P.

    2009-01-01

    Context: Unplanned readmission within 30 days of discharge is an indicator of hospital quality. Purpose: We wanted to determine whether older rural veterans who were enrolled in the VA had different rates of unplanned readmission to VA or non-VA hospitals than their urban counterparts. Methods: We used the combined VA/Medicare dataset to examine…

  6. 75 FR 61252 - Proposed Information Collection (Create Payment Request for the VA Funding Fee Payment System (VA...

    Science.gov (United States)

    2010-10-04

    ... Payment Request for the VA Funding Fee Payment System (VA FFPS); A Computer Generated Funding Fee Receipt... Payment Request for the VA Funding Fee Payment System (VA FFPS); A Computer Generated Funding Fee Receipt... information through the Federal Docket Management System (FDMS) at http://www.Regulations.gov or to Nancy J...

  7. 78 FR 59771 - Proposed Information Collection (Create Payment Request for the VA Funding Fee Payment System (VA...

    Science.gov (United States)

    2013-09-27

    ... Payment Request for the VA Funding Fee Payment System (VA FFPS); a Computer Generated Funding Fee Receipt.... Title: Create Payment Request for the VA Funding Fee Payment System (VA FFPS); A Computer Generated... through the Federal Docket Management System (FDMS) at www.Regulations.gov or to Nancy J. Kessinger...

  8. 75 FR 61859 - Proposed Information Collection (Create Payment Request for the VA Funding Fee Payment System (VA...

    Science.gov (United States)

    2010-10-06

    ... Payment Request for the VA Funding Fee Payment System (VA FFPS); A Computer Generated Funding Fee Receipt... Payment Request for the VA Funding Fee Payment System (VA FFPS); A Computer Generated Funding Fee Receipt... information through the Federal Docket Management System (FDMS) at http://www.Regulations.gov or to Nancy J...

  9. VaST: A variability search toolkit

    Science.gov (United States)

    Sokolovsky, K. V.; Lebedev, A. A.

    2018-01-01

    Variability Search Toolkit (VaST) is a software package designed to find variable objects in a series of sky images. It can be run from a script or interactively using its graphical interface. VaST relies on source list matching as opposed to image subtraction. SExtractor is used to generate source lists and perform aperture or PSF-fitting photometry (with PSFEx). Variability indices that characterize scatter and smoothness of a lightcurve are computed for all objects. Candidate variables are identified as objects having high variability index values compared to other objects of similar brightness. The two distinguishing features of VaST are its ability to perform accurate aperture photometry of images obtained with non-linear detectors and handle complex image distortions. The software has been successfully applied to images obtained with telescopes ranging from 0.08 to 2.5 m in diameter equipped with a variety of detectors including CCD, CMOS, MIC and photographic plates. About 1800 variable stars have been discovered with VaST. It is used as a transient detection engine in the New Milky Way (NMW) nova patrol. The code is written in C and can be easily compiled on the majority of UNIX-like systems. VaST is free software available at http://scan.sai.msu.ru/vast/.

  10. Colonization of new land by arbuscular mycorrhizal fungi

    DEFF Research Database (Denmark)

    Nielsen, Knud Nor; Kjøller, Rasmus; Bruun, Hans Henrik

    2016-01-01

    The study describes the primary assembly of arbuscular mycorrhizal communities on a newly constructed island Peberholm between Denmark and Sweden. The AM fungal community on Peberholm was compared with the neighboring natural island Saltholm. The structure of arbuscular mycorrhizal communities wa...

  11. Molecular characterisation of a mycorrhizal inoculant that enhances ...

    African Journals Online (AJOL)

    SERVER

    2007-07-04

    Jul 4, 2007 ... lum used as biological models originated from the same desert area. In order to identify this mycorrhizal fungal inoculum, a molecular approach developed by Helgason et al. (1999) was adapted. The small subunit 18S from the roots of mycorrhizal T. alexandrium was amplified using primers NS31 and ...

  12. Soil Solution Phosphorus Status and Mycorrhizal Dependency in Leucaena leucocephala†

    Science.gov (United States)

    Habte, Mitiku; Manjunath, Aswathanarayan

    1987-01-01

    A phosphorus sorption isotherm was used to establish concentrations of P in a soil solution ranging from 0.002 to 0.807 μg/ml. The influence of P concentration on the symbiotic interaction between the tropical tree legume Leucaena leucocephala and the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus fasciculatum was evaluated in pot experiments. The level of mycorrhizal infection in Leucaena roots increased as the concentration of P was raised from 0.002 to 0.153 μg/ml. Higher levels of P depressed mycorrhizal infection, but the level of infection never declined below 50%. Periodic monitoring of P contents of Leucaena subleaflets indicated that significant mycorrhizal activity was detected as early as 17 days after planting, with the activity peaking 12 to 16 days thereafter. The highest level of mycorrhizal activity was associated with a soil solution P level of 0.021 μg/ml. Even though the mycorrhizal inoculation effect diminished as the concentration of P in the soil solution was increased, mycorrhizal inoculation significantly increased P uptake and dry-matter yield of Leucaena at all levels of soil solution P examined. The concentration of P required by nonmycorrhizal L. leucocephala for maximum yield was 27 to 38 times higher than that required by mycorrhizal L. leucocephala. The results illustrate the very high dependence of L. leucocephala on VAM fungi and the significance of optimizing soil solution phosphorus for enhancing the benefits of the VAM symbiosis. PMID:16347323

  13. Mycorrhizal association of some agroforestry tree species in two ...

    African Journals Online (AJOL)

    Mycorrhizal colonization of different agroforestry tree species in two social forestry nurseries was investigated. Percentage of Arbuscular mycorrhizal (AM) infection, number of resting spores and AM fungi species varies both in tree species as well as in two different nurseries. This variation is attributed to various factors such ...

  14. Soil Solution Phosphorus Status and Mycorrhizal Dependency in Leucaena leucocephala.

    Science.gov (United States)

    Habte, M; Manjunath, A

    1987-04-01

    A phosphorus sorption isotherm was used to establish concentrations of P in a soil solution ranging from 0.002 to 0.807 mug/ml. The influence of P concentration on the symbiotic interaction between the tropical tree legume Leucaena leucocephala and the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus fasciculatum was evaluated in pot experiments. The level of mycorrhizal infection in Leucaena roots increased as the concentration of P was raised from 0.002 to 0.153 mug/ml. Higher levels of P depressed mycorrhizal infection, but the level of infection never declined below 50%. Periodic monitoring of P contents of Leucaena subleaflets indicated that significant mycorrhizal activity was detected as early as 17 days after planting, with the activity peaking 12 to 16 days thereafter. The highest level of mycorrhizal activity was associated with a soil solution P level of 0.021 mug/ml. Even though the mycorrhizal inoculation effect diminished as the concentration of P in the soil solution was increased, mycorrhizal inoculation significantly increased P uptake and dry-matter yield of Leucaena at all levels of soil solution P examined. The concentration of P required by nonmycorrhizal L. leucocephala for maximum yield was 27 to 38 times higher than that required by mycorrhizal L. leucocephala. The results illustrate the very high dependence of L. leucocephala on VAM fungi and the significance of optimizing soil solution phosphorus for enhancing the benefits of the VAM symbiosis.

  15. Impact of fertilizer, corn residue, and cover crops on mycorrhizal inoculum potential and arbuscular mycorrhizal fungi associations

    Science.gov (United States)

    Arbuscular Mycorrhizal Fungi (AMF) increase nutrient and water acquisition for mycorrhizal-susceptible plants, which may lead to higher yields. However, intensive agricultural practices such as tilling, fallow treatments, and inorganic nutrient application reduce soil AMF. The purpose of the three e...

  16. Differential access to phosphorus pools of an Oxisol by mycorrhizal and non-mycorrhizal maize

    NARCIS (Netherlands)

    Cardoso, I.M.; Boddington, C.L.; Janssen, B.H.; Oenema, O.; Kuyper, T.W.

    2006-01-01

    This study investigated whether arbuscular mycorrhizal fungi (AMF) could take up phosphorus (P) from pools that are normally considered unavailable to plants. An aluminum (Al) resistant maize variety, inoculated with three species of Glomus or uninoculated, supplied with nutrient solution without P,

  17. Spore communities of arbuscular mycorrhizal fungi and mycorrhizal associations in different ecosystems, south Australia

    Directory of Open Access Journals (Sweden)

    Z. I. Antoniolli

    2002-09-01

    Full Text Available Communities of arbuscular mycorrhizal fungi (AMF were surveyed in different South Australian ecosystems. The soil was wet-sieved for spore extraction, followed by the determination of presence and abundance of AMF species as well as the percentage of root colonization. Mycorrhizal associations were common and there was substantial fungal diversity in different ecosystems. Spores were most abundant in the permanent pasture system and less abundant under continuous wheat. The incidence of mycorrhizal associations in different plant species and the occurrence of Arum and Paris type colonization generally conformed with previous information. Spores of seventeen AMF were verified throughout seasonal changes in 1996 and 1997 in the permanent pasture and on four host species (Lolium perenne, Plantago lanceolata, Sorghum sp. and Trifolium subterraneum , set up with the same soils under greenhouse conditions. Glomus mosseae was the dominant spore type at all sampling times and in all trap cultures. Mycorrhizal diversity was significantly affected by different sampling times in trap cultures but not in field-collected soil. P. lanceolata, Sorghum sp. and T. subterraneum as hosts for trap cultures showed no differences in richness and diversity of AMF spores that developed in association with their roots. Abundance and diversity were lowest, however, in association with L. perenne , particularly in December 1996. Results show that the combination of spore identification from field-collected soil and trap cultures is essential to study population and diversity of AMF. The study provides baseline data for ongoing monitoring of mycorrhizal populations using conventional methods and material for the determination of the symbiotic effectiveness of AMF key members.

  18. The VA mission act: Funding to fail?

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2018-06-01

    Full Text Available No abstract available. Article truncated after 150 words. Yesterday on D-Day, the 74th anniversary of the invasion of Normandy, President Trump signed the VA Mission Act. The law directs the VA to combine a number of existing private-care programs, including the so-called Choice program, which was created in 2014 after veterans died waiting for appointments at the Phoenix VA (1. During the signing Trump touted the new law saying “there has never been anything like this in the history of the VA” and saying that veterans “can go right outside [the VA] to a private doctor”-but can they? Although the bill authorizes private care, it appropriates no money to pay for it. Although a bipartisan plan to fund the expansion is proposed in the House, the White House has been lobbying Republicans to vote the plan down (2. Instead Trump has been asking Congress to pay for veteran’s programs by cutting spending elsewhere (2. We in Arizona are …

  19. Assessing the quality of VA Human Research Protection Programs: VA vs. affiliated University Institutional Review Board.

    Science.gov (United States)

    Tsan, Min-Fu; Nguyen, Yen; Brooks, Robert

    2013-04-01

    We compared the Human Research Protection Program (HRPP) quality indicator data of the Department of Veterans Affairs (VA) facilities using their own VA institutional review boards (IRBs) with those using affiliated university IRBs. From a total of 25 performance metrics, 13 did not demonstrate statistically significant differences, while 12 reached statistically significance differences. Among the 12 with statistically significant differences, facilities using their own VA IRBs performed better on four of the metrics, while facilities using affiliate IRBs performed better on eight. However, the absolute difference was small (0.2-2.7%) in all instances, suggesting that they were of no practical significance. We conclude that it is acceptable for facilities to use their own VA IRBs or affiliated university IRBs as their IRBs of record.

  20. 38 CFR 74.27 - How will VA store information?

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) VETERANS SMALL BUSINESS REGULATIONS Records Management § 74.27 How will VA store information? VA... examination visits will be scanned onto portable media and fully secured in the Center for Veterans Enterprise...

  1. 77 FR 67063 - VA Directive 0005 on Scientific Integrity

    Science.gov (United States)

    2012-11-08

    ... in multiple areas, including data integrity, ethics, privacy, and human research protections, as well... replace the Association for the Accreditation of Human Research Protection Programs (AAHRPP) with Alion... human research protection programs. VA Response: VA is currently reviewing its accreditation...

  2. Accessing VA Healthcare During Large-Scale Natural Disasters.

    Science.gov (United States)

    Der-Martirosian, Claudia; Pinnock, Laura; Dobalian, Aram

    2017-01-01

    Natural disasters can lead to the closure of medical facilities including the Veterans Affairs (VA), thus impacting access to healthcare for U.S. military veteran VA users. We examined the characteristics of VA patients who reported having difficulty accessing care if their usual source of VA care was closed because of natural disasters. A total of 2,264 veteran VA users living in the U.S. northeast region participated in a 2015 cross-sectional representative survey. The study used VA administrative data in a complex stratified survey design with a multimode approach. A total of 36% of veteran VA users reported having difficulty accessing care elsewhere, negatively impacting the functionally impaired and lower income VA patients.

  3. Effect of arbuscular mycorrhizal fungal inoculation on growth, and ...

    African Journals Online (AJOL)

    FAMA

    2015-09-30

    Sep 30, 2015 ... AMF on root colonization, biomass production, mycorrhizal dependency (MD) and shoot mineral ... four months of growth in a sterilized soil and greenhouse conditions, grasses inoculated with AMF ..... Quetta, Pakistan.

  4. Role of arbuscular mycorrhizal fungi in phytoremediation of heavy ...

    African Journals Online (AJOL)

    sadia

    2016-05-18

    May 18, 2016 ... Sciences, Quaid-i-Azam University, Islamabad, Pakistan. Received 19 ... weeks of pot experiment, roots colonization, shoot and root biomass, growth, heavy metals contents ... using arbuscular mycorrhizal fungi (AMF) in soil.

  5. Composition of arbuscular mycorrhizal fungi associated with cassava

    African Journals Online (AJOL)

    SARAH

    2016-02-29

    Feb 29, 2016 ... Objectives: Arbuscular mycorrhizal fungi (AMF) form root symbiotic relationships with higher plants, but .... including growth habit of stem, stem colour, outer and inner root ..... of AM fungi to colonize roots, breaking down their.

  6. Mycorrhizal responses to biochar in soil-concepts and mechanisms.

    NARCIS (Netherlands)

    Warnock, D.D.; Lehmann, J.; Kuyper, T.W.; Rillig, M.C.

    2007-01-01

    Experiments suggest that biomass-derived black carbon (biochar) affects microbial populations and soil biogeochemistry. Both biochar and mycorrhizal associations, ubiquitous symbioses in terrestrial ecosystems, are potentially important in various ecosystem services provided by soils, contributing

  7. Inoculation of Ceratonia siliqua L. with native arbuscular mycorrhizal ...

    African Journals Online (AJOL)

    Inoculation of Ceratonia siliqua L. with native arbuscular mycorrhizal fungi mixture improves seedling establishment under greenhouse conditions. Ouahmane Lahcen, Ndoye Ibrahima, Morino Abdessadek, Ferradous Abderrahim, Sfairi Youssef, Al Faddy Mohamed Najib, Abourouh Mohamed ...

  8. Host plant quality mediates competition between arbuscular mycorrhizal fungi

    NARCIS (Netherlands)

    Knegt, B.; Jansa, J.; Franken, O.; Engelmoer, D.J.P.; Werner, G.D.A.; Bücking, H.; Kiers, E.T.

    2016-01-01

    Arbuscular mycorrhizal fungi exchange soil nutrients for carbon from plant hosts. Empirical works suggests that hosts may selectively provide resources to different fungal species, ultimately affecting fungal competition. However, fungal competition may also be mediated by colonization strategies of

  9. Molecular trait indicators: Moving beyond phylogeny in arbuscular mycorrhizal ecology

    NARCIS (Netherlands)

    Gamper, H.A.; van der Heijden, M.; Kowalchuk, G.A.

    2010-01-01

    Arbuscular mycorrhizal (AM) fungi form symbiotic associations with the roots of most plants, thereby mediating nutrient and carbon fluxes, plant performance, and ecosystem dynamics. Although considerable effort has been expended to understand the keystone ecological position of AM symbioses, most

  10. Diversity and biogeography of arbuscular mycorrhizal fungi in agricultural soils

    Czech Academy of Sciences Publication Activity Database

    Oehl, F.; Laczko, E.; Oberholzer, H.-R.; Jansa, Jan; Egli, S.

    2017-01-01

    Roč. 53, č. 7 (2017), s. 777-797 ISSN 0178-2762 Institutional support: RVO:61388971 Keywords : Arbuscular mycorrhizal * Agriculture * Biodiversity Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.683, year: 2016

  11. Effect of vesicular arbuscular mycorrhizal fungus on the ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-10-06

    Oct 6, 2008 ... ... association between certain plants and microorganisms plays an important role in soil ..... an Agrostis capillaris population on a copper contaminated soil. Plant ... vesicular-arbuscular mycorrhizal fungi in Amazonian Peru.

  12. Plant hormones as signals in arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Miransari, Mohammad; Abrishamchi, A; Khoshbakht, K; Niknam, V

    2014-06-01

    Arbuscular mycorrhizal (AM) fungi are non-specific symbionts developing mutual and beneficial symbiosis with most terrestrial plants. Because of the obligatory nature of the symbiosis, the presence of the host plant during the onset and proceeding of symbiosis is necessary. However, AM fungal spores are able to germinate in the absence of the host plant. The fungi detect the presence of the host plant through some signal communications. Among the signal molecules, which can affect mycorrhizal symbiosis are plant hormones, which may positively or adversely affect the symbiosis. In this review article, some of the most recent findings regarding the signaling effects of plant hormones, on mycorrhizal fungal symbiosis are reviewed. This may be useful for the production of plants, which are more responsive to mycorrhizal symbiosis under stress.

  13. Mycorrhizal symbiosis: ancient signalling mechanisms co-opted

    NARCIS (Netherlands)

    Geurts, R.; Vleeshouwers, V.G.A.A.

    2012-01-01

    Mycorrhizal root endosymbiosis is an ancient property of land plants. Two parallel studies now provide novel insight into the mechanism driving this interaction and how it is used by other filamentous microbes like pathogenic oomycetes.

  14. Troubles continue for the Phoenix VA

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-10-01

    Full Text Available No abstract available. Article truncated after 150 words. According to the Joint Commission on the Accreditation of Healthcare Organizations (Joint Commission, JCAHO, an independent organization that reviews hospitals, the Phoenix VA does not comply with U.S. standards for safety, patient care and management (1. The hospital was at the epicenter of the national scandal over the quality of care being afforded to the nation's veterans where the now notorious practice of double-booking patient appointments was first exposed. The hospital's indifferent management provoked congressional investigations that uncovered still more system-wide abuses leading to the removal of the hospital director and the resignation of then VA secretary, Eric Shinseki. The hospital maintains its accreditation but with a follow-up survey in 1-6 months where it must show that it has successfully addressed the 13 identified problems (1. Inspectors who conducted the review in July found that VA employees were unable to report concerns "without retaliatory action from the hospital." Other alarming ...

  15. VA announces aggressive new approach to produce rapid improvements in VA medical centers

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2018-02-01

    Full Text Available No abstract available. Article truncated at 150 words. The U.S. Department of Veterans Affairs (VA announced steps that it is taking as part of an aggressive new approach to produce rapid improvements at VA’s low-performing medical facilities nationwide (1. VA defines its low-performing facilities as those medical centers that receive the lowest score in its Strategic Analytics for Improvement and Learning (SAIL star rating system, or a one-star rating out of five. The SAIL star rating was initiated in 2016 and uses a variety of measures including mortality, length of hospital stay, readmission rates, hospital complications, physician productivity and efficiency. A complete listing of the VA facilities, their star ratings and the metrics used to determine the ratings is available through the end of fiscal year 2017 (2. Based on the latest ratings, the VA currently has 15 one-star facilities including Denver, Loma Linda, and Phoenix in the Southwest (Table 1. Table 1. VA facilities with one-star ratings …

  16. Optical properties of arbuscular mycorrhizal fungal structures

    International Nuclear Information System (INIS)

    Perez, Adverdi; V-Hernandez, Alejandra; Rudamas, Carlos; Dreyer, Beatriz

    2008-01-01

    It was already reported by B. Dreyer at al. [1] that all fungal structures, both intra- and extra-radical fluoresced under blue light excitation regardless of their state (dead or alive). The source of the so called autofluorescence appears to be localized in the fungal cell wall. This supports the use of photoluminescence for the evaluation of AM colonization. However, the interpretation of these results is still in discussion [1-4]. In this work, arbuscular mycorrhizal spores were isolated from the rhizosphere of mango (Mangifera indica L.) plants by the method of wet sieving and decanting of Gerdemann and Nicolson [5] and studied by photoluminescence spectroscopy. Our experimental setup consists of an epifluorescence microscope (EM) coupled to a CCD-spectrometer through an arrangement of a home-made-telescope + fiber optic. This experimental setup allows the capture of images of the mycorrhizal structures (as usual in a standard epifluorescence microscope) combined with measurements of their corresponding emission bands. The preliminary results based on images obtained by standard EM do not clearly show that the emission is originated in the fungal cell walls as reported in Ref. 1. On the other hand, a very broad emission band in the visible part of the electromagnetic spectrum was observed in these spores by exciting at 450-490 nm and 300- 380 nm. We obtain a Full Width at Half Maximum (FWHM) of around 200 nm for this emission band whichis centered at 515 nm. This broad band seems to be composed of two narrower bands peaked around 494 and 547 nm and with FWHM of 50 nm and 150 nm, respectively. The profile of the observed emission band is in good agreement with the bands reported in Ref. 1 for vesicles, arbuscules and spores measured using the λ-Scan of a confocal laser scanning microscope. However, our results for spores show that the maxima of the narrower bands are shifted to higher energies in comparison to the corresponding bands observed in Ref. 1

  17. Plant litter chemistry and mycorrhizal roots promote a nitrogen feedback in a temperate forest.

    Science.gov (United States)

    Nina Wurzburger; Ronald L. Hendrick

    2009-01-01

    1. Relationships between mycorrhizal plants and soil nitrogen (N) have led to the speculation that the chemistry of plant litter and the saprotrophy of mycorrhizal symbionts can function together to...

  18. Variability in colonization of arbuscular mycorrhizal fungi and its effect on mycorrhizal dependency of improved and unimproved soybean cultivars.

    Science.gov (United States)

    Salloum, M S; Guzzo, M C; Velazquez, M S; Sagadin, M B; Luna, C M

    2016-12-01

    Breeding selection of germplasm under fertilized conditions may reduce the frequency of genes that promote mycorrhizal associations. This study was developed to compare variability in mycorrhizal colonization and its effect on mycorrhizal dependency (MD) in improved soybean genotypes (I-1 and I-2) with differential tolerance to drought stress, and in unimproved soybean genotypes (UI-3 and UI-4). As inoculum, a mixed native arbuscular mycorrhizal fungi (AMF) was isolated from soybean roots, showing spores mostly of the species Funneliformis mosseae. At 20 days, unimproved genotypes followed by I-2, showed an increase in arbuscule formation, but not in I-1. At 40 days, mycorrhizal plants showed an increase in nodulation, this effect being more evident in unimproved genotypes. Mycorrhizal dependency, evaluated as growth and biochemical parameters from oxidative stress was increased in unimproved and I-2 since 20 days, whereas in I-1, MD increased at 40 days. We cannot distinguish significant differences in AMF colonization and MD between unimproved and I-2. However, variability among improved genotypes was observed. Our results suggest that selection for improved soybean genotypes with good and rapid AMF colonization, particularly high arbuscule/hyphae ratio could be a useful strategy for the development of genotypes that optimize AMF contribution to cropping systems.

  19. Sequestration of Carbon in Mycorrhizal Fungi Under Nitrogen Fertilization

    Science.gov (United States)

    Treseder, K. K.; Turner, K. M.

    2005-12-01

    Mycorrhizal fungi are root symbionts that facilitate plant uptake of soil nutrients in exchange for plant carbohydrates. They grow in almost every terrestrial ecosystem on earth, form relationships with about 80% of plant species, and receive 10 to 20% of the carbon fixed by their host plants. As such, they could potentially sequester a significant amount of carbon in ecosystems. We hypothesized that nitrogen fertilization would decrease carbon storage in mycorrhizal fungi, because plants should reduce investment of carbon in mycorrhizal fungi when nitrogen availability is high. We measured the abundance of two major groups of mycorrhizal fungi, arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi, in control and nitrogen-fertilized plots within three boreal ecosystems of inland Alaska. The ecosystems represented different recovery stages following severe fire, and comprised a young site dominated by AM fungi, an old site dominated by ECM fungi, and an intermediate site co-dominated by both groups. Pools of mycorrhizal carbon included root-associated AM and ECM structures, soil-associated AM hyphae, and soil-associated glomalin. Glomalin is a glycoprotein produced only by AM fungi. It is present in the cell walls of AM hyphae, and then is deposited in the soil as the hyphae senesce. Nitrogen significantly altered total mycorrhizal carbon pools, but its effect varied by site (site * N interaction, P = 0.05). Under nitrogen fertilization, mycorrhizal carbon was reduced from 99 to 50 g C m2 in the youngest site, was increased from 124 to 203 g C m2 in the intermediate-aged site, and remained at 35 g C m2 in the oldest site. The changes in total mycorrhizal carbon stocks were driven mostly by changes in glomalin (site * N interaction, P = 0.05), and glomalin stocks were strongly correlated with AM hyphal abundance (P stocks within root-associated AM structures increased significantly with nitrogen fertilization across all sites (P = 0.001), as did root

  20. VA Vascular Injury Study (VAVIS): VA-DoD extremity injury outcomes collaboration.

    Science.gov (United States)

    Shireman, Paula K; Rasmussen, Todd E; Jaramillo, Carlos A; Pugh, Mary Jo

    2015-02-03

    Limb injuries comprise 50-60% of U.S. Service member's casualties of wars in Afghanistan and Iraq. Combat-related vascular injuries are present in 12% of this cohort, a rate 5 times higher than in prior wars. Improvements in medical and surgical trauma care, including initial in-theatre limb salvage approaches (IILS) have resulted in improved survival and fewer amputations, however, the long-term outcomes such as morbidity, functional decline, and risk for late amputation of salvaged limbs using current process of care have not been studied. The long-term care of these injured warfighters poses a significant challenge to the Department of Defense (DoD) and Department of Veterans Affairs (VA). The VA Vascular Injury Study (VAVIS): VA-DoD Extremity Injury Outcomes Collaborative, funded by the VA, Health Services Research and Development Service, is a longitudinal cohort study of Veterans with vascular extremity injuries. Enrollment will begin April, 2015 and continue for 3 years. Individuals with a validated extremity vascular injury in the Department of Defense Trauma Registry will be contacted and will complete a set of validated demographic, social, behavioral, and functional status measures during interview and online/ mailed survey. Primary outcome measures will: 1) Compare injury, demographic and geospatial characteristics of patients with IILS and identify late vascular surgery related limb complications and health care utilization in Veterans receiving VA vs. non-VA care, 2) Characterize the preventive services received by individuals with vascular repair and related outcomes, and 3) Describe patient-reported functional outcomes in Veterans with traumatic vascular limb injuries. This study will provide key information about the current process of care for Active Duty Service members and Veterans with polytrauma/vascular injuries at risk for persistent morbidity and late amputation. The results of this study will be the first step for clinicians in VA and

  1. 48 CFR 853.215-70 - VA Form 10-1170, Application for Furnishing Nursing Home Care to Beneficiaries of VA.

    Science.gov (United States)

    2010-10-01

    ..., Application for Furnishing Nursing Home Care to Beneficiaries of VA. 853.215-70 Section 853.215-70 Federal... 853.215-70 VA Form 10-1170, Application for Furnishing Nursing Home Care to Beneficiaries of VA. VA Form 10-1170, Application for Furnishing Nursing Home Care to Beneficiaries of VA, will be used for...

  2. Mycorrhizal symbiosis produces changes in specific flavonoids in leaves of pepper plant (Capsicum annum L.)

    Science.gov (United States)

    In this study, experiments were performed to investigate if mycorrhizal plants grown under optimal growth conditions would improve crop quality compared to the non-mycorrhizal control. The results clearly showed that while mycorrhizal plants grown under an optimal nutrient supply did not increase t...

  3. Differences in arbuscular mycorrhizal fungi among three coffee cultivars in Puerto Rico

    Science.gov (United States)

    Ligia Lebrón; Jean D. Lodge; Paul. Bayman

    2012-01-01

    Mycorrhizal symbiosis is important for growth of coffee (Coffea arabica), but differences among coffee cultivars in response to mycorrhizal interactions have not been studied. We compared arbuscular mycorrhizal (AM) extraradical hyphae in the soil and diversity of AM fungi among three coffee cultivars, Caturra, Pacas, and Borbon, at three farms in...

  4. Niche differentiation and expansion of plant species are associated with mycorrhizal symbiosis

    NARCIS (Netherlands)

    Gerz, Maret; Guillermo Bueno, C.; Ozinga, Wim A.; Zobel, Martin; Moora, Mari

    2018-01-01

    Mycorrhizal symbiosis is a widespread association between plant roots and mycorrhizal fungi, which is thought to contribute to plant niche differentiation and expansion. However, this has so far not been explicitly tested. To address the effect of mycorrhizal symbiosis on plants’ realized niches, we

  5. SlaVaComp Fonts Converter

    Directory of Open Access Journals (Sweden)

    Simon Skilevic

    2013-12-01

    Full Text Available This paper presents a fonts converter that was developed as a part of the Freiburg project on historical corpus linguistics. The tool named SlaVaComp-Konvertierer converts Church Slavonic texts digitized with non-Unicode fonts into the Unicode format without any loss of information contained in the original file and without damage to the original formatting. It is suitable for the conversion of all idiosyncratic fonts—not only Church Slavonic—and therefore can be used not only in Palaeoslavistic, but also in all historical and philological studies.

  6. Enhanced tomato disease resistance primed by arbuscular mycorrhizal fungus.

    Science.gov (United States)

    Song, Yuanyuan; Chen, Dongmei; Lu, Kai; Sun, Zhongxiang; Zeng, Rensen

    2015-01-01

    Roots of most terrestrial plants form symbiotic associations (mycorrhiza) with soil- borne arbuscular mycorrhizal fungi (AMF). Many studies show that mycorrhizal colonization enhances plant resistance against pathogenic fungi. However, the mechanism of mycorrhiza-induced disease resistance remains equivocal. In this study, we found that mycorrhizal inoculation with AMF Funneliformis mosseae significantly alleviated tomato (Solanum lycopersicum Mill.) early blight disease caused by Alternaria solani Sorauer. AMF pre-inoculation led to significant increases in activities of β-1,3-glucanase, chitinase, phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX) in tomato leaves upon pathogen inoculation. Mycorrhizal inoculation alone did not influence the transcripts of most genes tested. However, pathogen attack on AMF-inoculated plants provoked strong defense responses of three genes encoding pathogenesis-related proteins, PR1, PR2, and PR3, as well as defense-related genes LOX, AOC, and PAL, in tomato leaves. The induction of defense responses in AMF pre-inoculated plants was much higher and more rapid than that in un-inoculated plants in present of pathogen infection. Three tomato genotypes: a Castlemart wild-type (WT) plant, a jasmonate (JA) biosynthesis mutant (spr2), and a prosystemin-overexpressing 35S::PS plant were used to examine the role of the JA signaling pathway in AMF-primed disease defense. Pathogen infection on mycorrhizal 35S::PS plants led to higher induction of defense-related genes and enzymes relative to WT plants. However, pathogen infection did not induce these genes and enzymes in mycorrhizal spr2 mutant plants. Bioassays showed that 35S::PS plants were more resistant and spr2 plants were more susceptible to early blight compared with WT plants. Our finding indicates that mycorrhizal colonization enhances tomato resistance to early blight by priming systemic defense response, and the JA signaling pathway is essential for mycorrhiza

  7. Medical Student Psychiatry Examination Performance at VA and Non-VA Clerkship Sites

    Science.gov (United States)

    Tucker, Phebe; von Schlageter, Margo Shultes; Park, EunMi; Rosenberg, Emily; Benjamin, Ashley B.; Nawar, Ola

    2009-01-01

    Objective: The authors examined the effects of medical student assignment to U.S. Department of Veterans Affairs (VA) Medical Center inpatient and outpatient psychiatry clerkship sites versus other university and community sites on the performance outcome measure of National Board of Medical Examiners (NBME) subject examination scores. Methods:…

  8. Visionary leadership and the future of VA health system.

    Science.gov (United States)

    Bezold, C; Mayer, E; Dighe, A

    1997-01-01

    As the U.S. Department of Veterans Affairs (VA) makes the change over to Veterans Integrated Service Network (VISNs) the need for new and better leadership is warranted if VA wants to not only survive, but thrive in the emerging twenty-first century healthcare system. VA can prepare for the future and meet the challenges facing them by adopting a system of visionary leadership. The use of scenarios and vision techniques are explained as they relate to VA's efforts to move toward their new system of VISNs. The four scenarios provide snapshots of possible futures for the U.S. healthcare system as well as the possible future role and mission of VA--from VA disappearing to its becoming a premier virtual organization.

  9. Mycorrhizal inoculation affects the phytochemical content in strawberry fruits

    Directory of Open Access Journals (Sweden)

    Ana Paula Cecatto

    2016-04-01

    Full Text Available The aim of this research was to evaluate the effect of the inoculation date of arbuscular mycorrhizal fungi on the fruit quality and the content of phytochemicals in a strawberry soilless growing system. The experiment was performed in Huelva (Spain and was conducted in a greenhouse on the La Rábida Campus of Huelva University under natural light and temperature from October 2013 to June 2014. Three short-day strawberry cultivars (‘Splendor’, ‘Sabrina’ and ‘Fortuna’ were grown in polyethylene bags filled with coconut fibres. Randomized block design, with 3 repetitions and factorial arrangement (3 cultivars x 3 treatments, was established. Each replicate consisted of one bag with 12 plants supporting structures at 40 cm height. The treatments were: T1 = mycorrhizal inoculation in the transplantation; T2 = mycorrhizal inoculation 30 days after transplantation (DAT; and T0 = control treatment, without inoculation. Arbuscular mycorrhizal fungi inoculation significantly affected the contents of anthocyanin and phenolics. When the inoculation is performed in the transplantation, the fruits showed a high content of anthocyanin and total phenolics. The mycorrhizal inoculation influences decreasing the acidity in fruit throughout the growing season and increase firmness only during the early stage of production.

  10. Assembly, Annotation, and Analysis of Multiple Mycorrhizal Fungal Genomes

    Energy Technology Data Exchange (ETDEWEB)

    Initiative Consortium, Mycorrhizal Genomics; Kuo, Alan; Grigoriev, Igor; Kohler, Annegret; Martin, Francis

    2013-03-08

    Mycorrhizal fungi play critical roles in host plant health, soil community structure and chemistry, and carbon and nutrient cycling, all areas of intense interest to the US Dept. of Energy (DOE) Joint Genome Institute (JGI). To this end we are building on our earlier sequencing of the Laccaria bicolor genome by partnering with INRA-Nancy and the mycorrhizal research community in the MGI to sequence and analyze dozens of mycorrhizal genomes of all Basidiomycota and Ascomycota orders and multiple ecological types (ericoid, orchid, and ectomycorrhizal). JGI has developed and deployed high-throughput sequencing techniques, and Assembly, RNASeq, and Annotation Pipelines. In 2012 alone we sequenced, assembled, and annotated 12 draft or improved genomes of mycorrhizae, and predicted ~;;232831 genes and ~;;15011 multigene families, All of this data is publicly available on JGI MycoCosm (http://jgi.doe.gov/fungi/), which provides access to both the genome data and tools with which to analyze the data. Preliminary comparisons of the current total of 14 public mycorrhizal genomes suggest that 1) short secreted proteins potentially involved in symbiosis are more enriched in some orders than in others amongst the mycorrhizal Agaricomycetes, 2) there are wide ranges of numbers of genes involved in certain functional categories, such as signal transduction and post-translational modification, and 3) novel gene families are specific to some ecological types.

  11. Dynamic of arbuscular mycorrhizal population on Amazon forest from the south Colombia

    International Nuclear Information System (INIS)

    Pena Vanegas, Clara P

    2001-01-01

    This work compared changes occurred on the number of arbuscular mycorrhizal spores at three mature forests and three regenerative forests, before and after clear-cutting. Results suggest that it is possible to predict the quantity of arbuscular mycorrhizal inocule after clear-cutting if initial number and type of forests is known before. A model to explain these changes shows that arbuscular mycorrhizal depletion on mature forests is about 70% after clear-cutting. Survival mycorrhizal populations colonize regenerative forests. Then, if a clear-cutting occurs on regenerative forests, arbuscular mycorrhizal populations will decrease on 35%, being less drastic that it occurred on mature forests

  12. Mycorrhizal associations as Salix repens L. communities in succession of dune ecosystems II Mycorrhizal dynamics and interactions of ectomycorrhizal and arbuscular mycorrhizal fungi

    NARCIS (Netherlands)

    Heijden, van der E.W.; Vosatka, M.

    2000-01-01

    Ectomycorrhizal (EcM) and arbuscular mycorrhizal (AM) associations of Salix repens were studied at 16 sites in different successional stages of dune ecosystems (calcareous-acidic, dry-wet) in the Netherlands. High EcM colonization, low AM colonization, and lack of differences between habitats

  13. Development of a parallelization method for KENO V.a

    International Nuclear Information System (INIS)

    Basoglu, B.; Bentley, C.; Dunn, M.

    1995-01-01

    The KENO V.a codes is a widely used Monte carlo codes that is part of the SCALE modular codes system for performing standardized computer analysis of nuclear systems for licensing evaluation. In the past few years, attempts have been made to speed up KENO V.a using new generation computers. In this paper we report on the initial development of a parallel version of KENO V.a for the Kendall Square Research supercomputer (KSRI) at ORNL. Investigations thus far have shown that the parallel code provides accurate results with significantly reduced computation times relative to the conventional KENO V.a code

  14. The potential of arbuscular mycorrhizal fungi application on aggregrate stability in alfisol soil

    Science.gov (United States)

    Syamsiyah, J.; Herawati, A.; Mujiyo

    2018-03-01

    The aim of this study was to determine the soil aggregate stability and its relationship with another variable in alfisol. The research used completely randomized design with four treatments: two sterilization levels (no sterilization and with sterilization) and two levels of mycorrhizal inoculation (no mycorrhizal and with mycorrhizal). Mycorrhizal (5 grams/pot) was inoculated before planting rice seeds. The soil aggregate stability was measured by wet-sieving and turbidimetric measurements. The results showed that soil aggregate stability was higher in mycorrhizal inoculated than non-mycorrhizal inoculated treatment, by 5% in sterilization soil and 3.2% in non-sterilization soil. The correlation analysis indicated that soil aggregate stability has a tight relationship with spore population, total glomalin, available glomalin, dry weight, tiller number of plant, and soil organic C. Inoculation of mycorrhizal contributed to stabilize soil aggregates in alfisol

  15. P depletion and activity of phosphatases in the rhizosphere of mycorrhizal and non-mycorrhizal cucumber (Cucumis Sativus L.)

    DEFF Research Database (Denmark)

    Joner, E.J.; Magid, J.; Gahoonia, T.S.

    1995-01-01

    An experiment was set up to test the ability of arbuscular mycorrhizal (AM) roots and hyphae to produce extracellular phosphatases and to study the relationship between phosphatase activity and soil organic P (P-o). Non-mycorrhizal cucumber and cucumber in symbiosis with either of two mycorrhizal...... fungi were grown in a sandy loam-sand mixture in three-compartment pots. Plant roots were separated from two consecutively adjoining compartments, first by a 37 m mesh excluding roots and subsequently by a 0.45 m membrane excluding mycorrhizal hyphae. Soil from the two root-free compartments...... was sectioned in a freezing microtome and analyzed for extracellular acid (pH 5.2) and alkaline (pH 8.5) phosphatase activity as well as depletion of NaHCO-3-extractable inorganic P (P-i) and P-o. Roots and mycorrhizal hyphae depleted the soil of P-i but did not influence the concentration of P-o in spite...

  16. Arbuscular mycorrhizal fungi and mycorrhizal stimulant affect dry matter and nutrient accumulation in bean and soybean plants

    Directory of Open Access Journals (Sweden)

    Fabrício Henrique Moreira Salgado

    2016-12-01

    Full Text Available The adoption of biological resources in agriculture may allow less dependence and better use of finite resources. This study aimed at evaluating the effects of inoculation with arbuscular mycorrhizal fungi native to the Brazilian Savannah associated with the application of mycorrhizal stimulant (7-hydroxy, 4'-methoxy-isoflavone, in the early growth of common bean and soybean. The experiment was carried out in a greenhouse, in a completely randomized design, with a 7 x 2 factorial arrangement, consisting of five arbuscular mycorrhizal fungi species, joint inoculation (junction of all species in equal proportions and native fungi (without inoculation, in the presence and absence of stimulant. The following traits were evaluated: shoot dry matter, root dry matter, mycorrhizal colonization, nodules dry matter and accumulation of calcium, zinc and phosphorus in the shoot dry matter. The increase provided by the arbuscular mycorrhizal fungi and the use of stimulant reached over 200 % in bean and over 80 % in soybean plants. The fungi Acaulospora scrobiculata, Dentiscutata heterogama, Gigaspora margarita and Rhizophagus clarus, for bean, and Claroideoglomus etunicatum, Dentiscutata heterogama, Rhizophagus clarus and the joint inoculation, for soybean, increased the dry matter and nutrients accumulation.

  17. Comparing Catheter-associated Urinary Tract Infection Prevention Programs Between VA and Non-VA Nursing Homes

    Science.gov (United States)

    Mody, Lona; Greene, M. Todd; Saint, Sanjay; Meddings, Jennifer; Trautner, Barbara W.; Wald, Heidi L.; Crnich, Christopher; Banaszak-Holl, Jane; McNamara, Sara E.; King, Beth J.; Hogikyan, Robert; Edson, Barbara; Krein, Sarah L.

    2018-01-01

    OBJECTIVE The impact of healthcare system integration on infection prevention programs is unknown. Using catheter-associated urinary tract infection (CAUTI) prevention as an example, we hypothesize that U.S. Department of Veterans Affairs (VA) nursing homes have a more robust infection prevention infrastructure due to integration and centralization compared with non-VA nursing homes. SETTING VA and non-VA nursing homes participating in the “AHRQ Safety Program for Long-term Care” collaborative. METHODS Nursing homes provided baseline information about their infection prevention programs to assess strengths and gaps related to CAUTI prevention. RESULTS A total of 353 (71%; 47 VA, 306 non-VA) of 494 nursing homes from 41 states responded. VA nursing homes reported more hours/week devoted to infection prevention-related activities (31 vs. 12 hours, P<.001), and were more likely to have committees that reviewed healthcare-associated infections. Compared with non-VA facilities, a higher percentage of VA nursing homes reported tracking CAUTI rates (94% vs. 66%, P<.001), sharing CAUTI data with leadership (94% vs. 70%, P=.014) and nursing personnel (85% vs. 56%, P=.003). However, fewer VA nursing homes reported having policies for appropriate catheter use (64% vs. 81%, P=.004) and catheter insertion (83% vs. 94%, P=.004). CONCLUSIONS Among nursing homes participating in an AHRQ-funded collaborative, VA and non-VA nursing homes differed in their approach to CAUTI prevention. Best practices from both settings should be applied universally to create an optimal infection prevention program within emerging integrated healthcare systems. PMID:27917728

  18. Genetics of mycorrhizal symbiosis in winter wheat (Triticum aestivum).

    Science.gov (United States)

    Lehnert, Heike; Serfling, Albrecht; Enders, Matthias; Friedt, Wolfgang; Ordon, Frank

    2017-07-01

    Bread wheat (Triticum aestivum) is a major staple food and therefore of prime importance for feeding the Earth's growing population. Mycorrhiza is known to improve plant growth, but although extensive knowledge concerning the interaction between mycorrhizal fungi and plants is available, genotypic differences concerning the ability of wheat to form mycorrhizal symbiosis and quantitative trait loci (QTLs) involved in mycorrhization are largely unknown. Therefore, a diverse set of 94 bread wheat genotypes was evaluated with regard to root colonization by arbuscular mycorrhizal fungi. In order to identify genomic regions involved in mycorrhization, these genotypes were analyzed using the wheat 90k iSelect chip, resulting in 17 823 polymorphic mapped markers, which were used in a genome-wide association study. Significant genotypic differences (P wheat. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  19. DNA extraction method for PCR in mycorrhizal fungi.

    Science.gov (United States)

    Manian, S; Sreenivasaprasad, S; Mills, P R

    2001-10-01

    To develop a simple and rapid DNA extraction protocol for PCR in mycorrhizal fungi. The protocol combines the application of rapid freezing and boiling cycles and passage of the extracts through DNA purification columns. PCR amplifiable DNA was obtained from a number of endo- and ecto-mycorrhizal fungi using minute quantities of spores and mycelium, respectively. DNA extracted following the method, was used to successfully amplify regions of interest from high as well as low copy number genes. The amplicons were suitable for further downstream applications such as sequencing and PCR-RFLPs. The protocol described is simple, short and facilitates rapid isolation of PCR amplifiable genomic DNA from a large number of fungal isolates in a single day. The method requires only minute quantities of starting material and is suitable for mycorrhizal fungi as well as a range of other fungi.

  20. Arbuscular mycorrhizal fungi decrease radiocesium accumulation in Medicago truncatula

    International Nuclear Information System (INIS)

    Gyuricza, Veronika; Declerck, Stephane; Dupre de Boulois, Herve

    2010-01-01

    The role of arbuscular mycorrhizal fungi (AMF) in plant radiocesium uptake and accumulation remains ambiguous. This is probably due to the presence of other soil microorganisms, the variability of soil characteristics and plant nutritional status or the availability of its chemical analogue, potassium (K). Here, we used an in vitro culture system to study the impact of increased concentration of K on radiocesium accumulation in non K-starved mycorrhizal and non-mycorrhizal Medicago truncatula plants. In the presence of AMF radiocesium uptake decreased regardless of the concentration of K, and its translocation from root to shoot was also significantly lower. Potassium also reduced the accumulation of radiocesium in plants but to a lesser extent than mycorrhization, and without any effect on translocation. These results suggest that AMF in combination with K can play a key role in reducing radiocesium uptake and its subsequent translocation to plant shoots, thereby representing good potential for improved phytomanagement of contaminated areas.

  1. Arbuscular mycorrhizal fungal responses to abiotic stresses: A review.

    Science.gov (United States)

    Lenoir, Ingrid; Fontaine, Joël; Lounès-Hadj Sahraoui, Anissa

    2016-03-01

    The majority of plants live in close collaboration with a diversity of soil organisms among which arbuscular mycorrhizal fungi (AMF) play an essential role. Mycorrhizal symbioses contribute to plant growth and plant protection against various environmental stresses. Whereas the resistance mechanisms induced in mycorrhizal plants after exposure to abiotic stresses, such as drought, salinity and pollution, are well documented, the knowledge about the stress tolerance mechanisms implemented by the AMF themselves is limited. This review provides an overview of the impacts of various abiotic stresses (pollution, salinity, drought, extreme temperatures, CO2, calcareous, acidity) on biodiversity, abundance and development of AMF and examines the morphological, biochemical and molecular mechanisms implemented by AMF to survive in the presence of these stresses. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Arbuscular mycorrhizal fungi decrease radiocesium accumulation in Medicago truncatula

    Energy Technology Data Exchange (ETDEWEB)

    Gyuricza, Veronika; Declerck, Stephane [Universite catholique de Louvain, Earth and Life Institute (ELI), Laboratoire de Mycologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium); Dupre de Boulois, Herve, E-mail: herve.dupre@uclouvain.b [Universite catholique de Louvain, Earth and Life Institute (ELI), Laboratoire de Mycologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium)

    2010-08-15

    The role of arbuscular mycorrhizal fungi (AMF) in plant radiocesium uptake and accumulation remains ambiguous. This is probably due to the presence of other soil microorganisms, the variability of soil characteristics and plant nutritional status or the availability of its chemical analogue, potassium (K). Here, we used an in vitro culture system to study the impact of increased concentration of K on radiocesium accumulation in non K-starved mycorrhizal and non-mycorrhizal Medicago truncatula plants. In the presence of AMF radiocesium uptake decreased regardless of the concentration of K, and its translocation from root to shoot was also significantly lower. Potassium also reduced the accumulation of radiocesium in plants but to a lesser extent than mycorrhization, and without any effect on translocation. These results suggest that AMF in combination with K can play a key role in reducing radiocesium uptake and its subsequent translocation to plant shoots, thereby representing good potential for improved phytomanagement of contaminated areas.

  3. Communities, populations and individuals of arbuscular mycorrhizal fungi

    DEFF Research Database (Denmark)

    Rosendahl, Søren

    2008-01-01

    Arbuscular mycorrhizal fungi in the phylum Glomeromycota are found globally in most vegetation types, where they form a mutualistic symbiosis with plant roots. Despite their wide distribution, only relatively few species are described. The taxonomy is based on morphological characters...... of the asexual resting spores, but molecular approaches to community ecology have revealed a considerable unknown diversity from colonized roots. Although the lack of genetic recombination is not unique in the fungal kingdom, arbuscular mycorrhizal fungi are probably ancient asexuals. The long asexual evolution...... of the fungi has resulted in considerable genetic diversity within morphologically recognizable species, and challenges our concepts of individuals and populations. This review critically examines the concepts of species, communities, populations and individuals of arbuscular mycorrhizal fungi....

  4. Interactions between aboveground herbivores and the mycorrhizal mutualists of plants.

    Science.gov (United States)

    Gehring, C A; Whitham, T G

    1994-07-01

    Plant growth, reproduction and survival can be affected both by mycorrhizal fungi and aboveground herbivores, but few studies have examined the interactive effects of these factors on plants. Most of the available data suggest that severe herbivory reduces root colonization by vesicular-arbuscular and ectomycorrhizal fungi. However, the reverse interaction has also been documented - mycorrhizal fungi deter herbivores and interact with fungal endophytes to influence herbivory. Although consistent patterns and mechanistic explanations are yet to emerge, it is likely that aboveground herbivore-mycorrhiza interactions have important implications for plant populations and communities. Copyright © 1994. Published by Elsevier Ltd.

  5. Can Microbial Ecology and Mycorrhizal Functioning Inform Climate Change Models?

    Energy Technology Data Exchange (ETDEWEB)

    Hofmockel, Kirsten; Hobbie, Erik

    2017-07-31

    Our funded research focused on soil organic matter dynamics and plant-microbe interactions by examining the role of belowground processes and mechanisms across scales, including decomposition of organic molecules, microbial interactions, and plant-microbe interactions associated with a changing climate. Research foci included mycorrhizal mediated priming of soil carbon turnover, organic N use and depolymerization by free-living microbes and mycorrhizal fungi, and the use of isotopes as additional constraints for improved modeling of belowground processes. This work complemented the DOE’s mandate to understand both the consequences of atmospheric and climatic change for key ecosystems and the feedbacks on C cycling.

  6. Common mycorrhizal networks and their effect on the bargaining power of the fungal partner in the arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Bücking, Heike; Mensah, Jerry A; Fellbaum, Carl R

    2016-01-01

    Arbuscular mycorrhizal (AM) fungi form mutualistic interactions with the majority of land plants, including some of the most important crop species. The fungus takes up nutrients from the soil, and transfers these nutrients to the mycorrhizal interface in the root, where these nutrients are exchanged against carbon from the host. AM fungi form extensive hyphal networks in the soil and connect with their network multiple host plants. These common mycorrhizal networks (CMNs) play a critical role in the long-distance transport of nutrients through soil ecosystems and allow the exchange of signals between the interconnected plants. CMNs affect the survival, fitness, and competitiveness of the fungal and plant species that interact via these networks, but how the resource transport within these CMNs is controlled is largely unknown. We discuss the significance of CMNs for plant communities and for the bargaining power of the fungal partner in the AM symbiosis.

  7. VA office of inspector general releases scathing report of Phoenix VA

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-08-01

    Full Text Available No abstract available. Article truncated at 150 words. The long-awaited Office of Inspector General’s (OIG report on the Phoenix VA Health Care System (PVAHCS was released on August 27, 2014 (1. The report was scathing in its evaluation of VA practices and leadership. Five questions were investigated: 1.Were there clinically significant delays in care? 2. Did PVAHCS omit the names of veterans waiting for care from its Electronic Wait List (EWL? 3. Were PVAHCS personnel not following established scheduling procedures? 4. Did the PVAHCS culture emphasize goals at the expense of patient care? 5. Are scheduling deficiencies systemic throughout the VA? In each case, the OIG found that the allegations were true. Despite initial denials, the OIG report showed that former PVAHCS director Sharon Helman, associate director Lance Robinson, hospital administration director Brad Curry, chief of staff Darren Deering and other senior executives were aware of delays in care and unofficial wait lists. Perhaps most disturbing is ...

  8. VA Dental Insurance Program--federalism. Direct final rule.

    Science.gov (United States)

    2013-10-22

    The Department of Veterans Affairs (VA) is taking direct final action to amend its regulations related to the VA Dental Insurance Program (VADIP), a pilot program to offer premium-based dental insurance to enrolled veterans and certain survivors and dependents of veterans. Specifically, this rule will add language to clarify the limited preemptive effect of certain criteria in the VADIP regulations.

  9. 76 FR 52230 - Establishment of Class E Airspace; Forest, VA

    Science.gov (United States)

    2011-08-22

    ...-0378; Airspace Docket No. 11-AEA-11] Establishment of Class E Airspace; Forest, VA AGENCY: Federal... at Forest, VA, to accommodate the new Area Navigation (RNAV) Global Positioning System (GPS) Standard... published in the Federal Register a notice of proposed rulemaking to establish Class E airspace at Forest...

  10. ESTIMASI NILAI VaR PORTOFOLIO MENGGUNAKAN FUNGSI ARCHIMEDEAN COPULA

    Directory of Open Access Journals (Sweden)

    AULIA ATIKA PRAWIBTA SUHARTO

    2017-01-01

    Full Text Available Value at Risk explains the magnitude of the worst losses occurred in financial products investments with a certain level of confidence and time interval. The purpose of this study is to estimate the VaR of portfolio using Archimedean Copula family. The methods for calculating the VaR are as follows: (1 calculating the stock return; (2 calculating descriptive statistics of return; (3 checking for the nature of autocorrelation and heteroscedasticity effects on stock return data; (4 checking for the presence of extreme value by using Pareto tail; (5 estimating the parameters of Achimedean Copula family; (6 conducting simulations of Archimedean Copula; (7 estimating the value of the stock portfolio VaR. This study uses the closing price of TLKM and GGRM. At 90% the VaR obtained using Clayton, Gumbel, Frank copulas are 0.9562%, 1.0189%, 0.9827% respectively. At 95% the VaR obtained using Clayton, Gumbel, Frank copulas are 1.2930%, 1.2522%, 1.3152% respectively. At 99% the VaR obtained using Clayton, Gumbel, Frank copulas are 2.0327%, 1.9164%, is 1.8678% respectively. In conclusion estimation of VaR using Clayton copula yields the highest VaR.

  11. 38 CFR 1.203 - Information to be reported to VA Police.

    Science.gov (United States)

    2010-07-01

    ... reported to VA Police. 1.203 Section 1.203 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS... be reported to VA Police. Information about actual or possible violations of criminal laws related to... occurs on VA premises, will be reported by VA management officials to the VA police component with...

  12. Home Health Care and Patterns of Subsequent VA and Medicare Health Care Utilization for Veterans

    Science.gov (United States)

    Van Houtven, Courtney Harold; Jeffreys, Amy S.; Coffman, Cynthia J.

    2008-01-01

    Purpose: The Veterans Affairs or VA health care system is in the process of significantly expanding home health care (HOC) nationwide. We describe VA HHC use in 2003 for all VA HHC users from 2002; we examine whether VA utilization across a broad spectrum of services differed for a sample of VA HHC users and their propensity-score-matched…

  13. VaR Methodology Application for Banking Currency Portfolios

    Directory of Open Access Journals (Sweden)

    Daniel Armeanu

    2007-02-01

    Full Text Available VaR has become the standard measure that financial analysts use to quantify market risk. VaR measures can have many applications, such as in risk management, to evaluate the performance of risk takers and for regulatory requirements, and hence it is very important to develop methodologies that provide accurate estimates. In particular, the Basel Committee on Banking Supervision at the Bank for International Settlements imposes to financial institutions such as banks and investment firms to meet capital requirements based on VaR estimates. In this paper we determine VaR for a banking currency portfolio and respect rules of National Bank of Romania regarding VaR report.

  14. Phenanthrene uptake by Medicago sativa L. under the influence of an arbuscular mycorrhizal fungus

    Energy Technology Data Exchange (ETDEWEB)

    Wu Naiying [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Department of Chemistry, Shangqiu Normal College, Shangqiu 476000 (China); Huang Honglin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Zhang Shuzhen, E-mail: szzhang@rcees.ac.c [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Zhu Yongguan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Christie, Peter [Agri-Environment Branch, Agriculture Food and Environmental Science Division, Agri-Food and Biosciences Institute, Newforge Lane, Belfast BT9 5PX (United Kingdom); Zhang Yong [State Key Laboratory of Marine Environmental Science, Environmental Science Research Centre, Xiamen University, Xiamen 361005 (China)

    2009-05-15

    Phenanthrene uptake by Medicago sativa L. was investigated under the influence of an arbuscular mycorrhizal fungus. Inoculation of lucerne with the arbuscular mycorrhizal fungus Glomus etunicatum L. resulted in higher phenanthrene accumulation in the roots and lower accumulation in the shoots compared to non-mycorrhizal controls. Studies on sorption and desorption of phenanthrene by roots and characterization of heterogeneity of mycorrhizal and non-mycorrhizal roots using solid-state {sup 13}C nuclear magnetic resonance spectroscopy ({sup 13}C NMR) demonstrated that increased aromatic components due to mycorrhizal inoculation resulted in enhanced phenanthrene uptake by the roots but lower translocation to the shoots. Direct visualization using two-photon excitation microscopy (TPEM) revealed higher phenanthrene accumulation in epidermal cells of roots and lower transport into the root interior and stem in mycorrhizal plants than in non-mycorrhizal controls. These results provide some insight into the mechanisms by which arbuscular mycorrhizal inoculation may influence the uptake of organic contaminants by plants. - Colonization by an arbuscular mycorrhizal fungus promoted root uptake and decreased shoot uptake of phenanthrene by Medicago sativa L.

  15. Phenanthrene uptake by Medicago sativa L. under the influence of an arbuscular mycorrhizal fungus

    International Nuclear Information System (INIS)

    Wu Naiying; Huang Honglin; Zhang Shuzhen; Zhu Yongguan; Christie, Peter; Zhang Yong

    2009-01-01

    Phenanthrene uptake by Medicago sativa L. was investigated under the influence of an arbuscular mycorrhizal fungus. Inoculation of lucerne with the arbuscular mycorrhizal fungus Glomus etunicatum L. resulted in higher phenanthrene accumulation in the roots and lower accumulation in the shoots compared to non-mycorrhizal controls. Studies on sorption and desorption of phenanthrene by roots and characterization of heterogeneity of mycorrhizal and non-mycorrhizal roots using solid-state 13 C nuclear magnetic resonance spectroscopy ( 13 C NMR) demonstrated that increased aromatic components due to mycorrhizal inoculation resulted in enhanced phenanthrene uptake by the roots but lower translocation to the shoots. Direct visualization using two-photon excitation microscopy (TPEM) revealed higher phenanthrene accumulation in epidermal cells of roots and lower transport into the root interior and stem in mycorrhizal plants than in non-mycorrhizal controls. These results provide some insight into the mechanisms by which arbuscular mycorrhizal inoculation may influence the uptake of organic contaminants by plants. - Colonization by an arbuscular mycorrhizal fungus promoted root uptake and decreased shoot uptake of phenanthrene by Medicago sativa L.

  16. Plant mycorrhizal traits in Europe in relation to climatic and edaphic gradients

    Science.gov (United States)

    Guillermo Bueno, C.; Gerz, Maret; Zobel, Martin; Moora, Mari

    2017-04-01

    Around 90% of plant species associate with mycorrhizal fungi. The symbiosis is known to provide plants with soil N, P and water, and fungi with plant photosynthesized carbohydrates. However, not all mycorrhizal symbioses are identical. The identity of associated plant and fungal species differs, as does the effect of the symbiosis on nutrient cycling and ecosystems more generally. In this study, we analysed the European distribution of two plant mycorrhizal traits in relation to climatic and edaphic drivers. We used the European distribution of the frequency of mycorrhizal colonization (plant mycorrhizal status); whether mycorrhizal fungi either always (obligately mycorrhizal, OM), or sometimes (facultatively mycorrhizal, FM) colonize plant roots, and the four main plant mycorrhizal types; arbuscular (AM), ecto-(ECM), ericoid (ERM), and non-mycorrhizal (NM) plants. We expected AM species to predominate in ecosystems where most soil nutrients occur in inorganic forms (lower latitudes) and those with higher soil pH. By contrast, due to the saprophytic abilities of ECM and ERM fungi, we expected ECM and ERM plants to predominate in ecosystems where nutrients are bound to organic compounds (higher latitudes) and those with lower soil pH. NM plant species are known to be common in disturbed habitats or in extremely phosphorus poor ecosystems, such as the Arctic tundra. Our results showed that the distribution of mycorrhizal types was driven by temperature and soil pH, with increases of NM, ECM and ERM, and decreases of AM, with latitude. FM predominated over OM species and this difference increased with latitude and was dependent on temperature drivers only. These results represent the first evidence at a European scale of plant mycorrhizal distribution patterns linked with climatic and edaphic gradients, supporting the idea of a tight relationship between the mycorrhizal symbiosis and nutrient cycling.

  17. In vitro culture of arbuscular mycorrhizal fungi: advances and future ...

    African Journals Online (AJOL)

    Arbuscular mycorrhizal (AM) fungi are ecologically important for most vascular plants for their growth and survival. AM fungi are obligate symbionts. In recent years, there have been many attempts to cultivate in vitro. Some relevant results indicate efforts are not far from successful growth of AM fungi independent of a plant ...

  18. Mycorrhizal fungi of aspen forests: Natural occurrence and potential applications

    Science.gov (United States)

    Cathy L. Cripps

    2001-01-01

    Native mycorrhizal fungi associated with aspen were surveyed on three soil types in the north-central Rocky Mountains. Selected isolates were tested for the ability to enhance aspen seedling growth in vitro. Over 50 species of ectomycorrhizal fungi occur with Populus tremuloides in this region, primarily basidiomycete fungi in the Agaricales. Almost one-third (30%)...

  19. Cropping enhances mycorrhizal benefits to maize in a tropical soil

    Czech Academy of Sciences Publication Activity Database

    Jemo, M.; Souleymanou, A.; Frossard, E.; Jansa, Jan

    2014-01-01

    Roč. 79, č. 2014 (2014), s. 117-124 ISSN 0038-0717 R&D Projects: GA MŠk(CZ) LK11224; GA ČR GAP504/12/1665 Institutional support: RVO:61388971 Keywords : tropical soil * mycorrhizal benefits * southern Cameroon Subject RIV: EE - Microbiology, Virology Impact factor: 3.932, year: 2014

  20. Inoculation of Ceratonia siliqua L. with native arbuscular mycorrhizal ...

    African Journals Online (AJOL)

    Ouhmane

    tree Ceratonia siliqua, a Mediterranean legume in Morocco. ... After 6 months of culturing in nursery conditions, height, shoot and root ... distributed around the world and the Mediterranean ... more resistant to water stress compared to other ... individual trees. ... mycorrhizal maize roots were used for the control treatment.

  1. Mycorrhizal specificity in the fully mycoheterotrophic Hexalectris Raf. (Orchidaceae: Epidendroideae)

    Science.gov (United States)

    Aaron H. Kennedy; D. Lee Taylor; Linda E. Watson

    2011-01-01

    Mycoheterotrophic species have abandoned an autotrophic lifestyle and obtain carbon exclusively from mycorrhizal fungi. Although these species have evolved independently in many plant families, such events have occurred most often in the Orchidaceae, resulting in the highest concentration of these species in the tracheophytes. Studies of mycoheterotrophic species...

  2. Arsenic uptake and phytoremediation potential by arbuscular mycorrhizal fungi

    Science.gov (United States)

    Xinhua He; Erik Lilleskov

    2014-01-01

    Arsenic (As) contamination of soils and water is a global problem because of its impacts on ecosystems and human health. Various approaches have been attempted for As remediation, with limited success. Arbuscular mycorrhizal (AM) fungi play vital roles in the uptake of water and essential nutrients, especially phosphorus (P), and hence enhance plant performance and...

  3. Effect of mycorrhizal inoculum and urea fertilizer on diseases ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-18

    Aug 18, 2008 ... Ambang Zachée*, Ndongo Bekolo, Bime, Ngoh Dooh, Maho Yalen and .... and 29°C. The soil is classified as the ferruginous tropical soil. According to the description of the physical properties of the soil by ... mycorrhizal inoculation, showed different variations of .... Cahiers ORSTOM, Paris, France.

  4. Arbuscular-mycorrhizal fungi (Glomales) in Egypt. III: Distribution ...

    African Journals Online (AJOL)

    Roots and rhizospheric soils of 26 plant species belonging to 18 families representing five different habitats at El-Omayed Biosphere Reserve were collected and examined for arbuscular-mycorrhizal fungal (AMF) associations. Plant species recorded in the habitat of coastal sand dunes had the highest percentage of ...

  5. Mycorrhizal inoculation of pecan seedlings with some marketable truffles

    Directory of Open Access Journals (Sweden)

    Gian M. Benucci

    2013-12-01

    Full Text Available Pecan is the common name of Carya illinoinensis (Wangenh. K. Koch, an ectomycorrhizal tree native to North America, also frequently known as hickory. Mycorrhizal inoculations of pecan seedlings with: Tuber aestivum Vittad., T. borchii Vittad., T. indicum Cooke & Massee, and T. lyonii Butters are described and discussed.

  6. Solanum cultivar responses to arbuscular mycorrhizal fungi: growth ...

    African Journals Online (AJOL)

    A greenhouse experiment was carried out in a sandy soil with a low available phosphorus to evaluate responsiveness of four Solanum aethiopicum cultivars to indigenous arbuscular mycorrhizal fungi. Results showed clear interaction between genetic variability of cultivars and fungal isolates on shoot biomass and on ...

  7. Effect of arbuscular mycorrhizal fungal inoculation on growth, and ...

    African Journals Online (AJOL)

    The aim of our work was to assess the effect of inoculation with three arbuscular mycorrhizal fungi (AMF) (Rhizoglomus aggregatum (N.C. Schenck and G.S. Sm.) Sieverd., G.A. Silva and Oeh., Funneliformis mosseae (T.H. Nicolson and Gerd.) C. Walker and A. Schüssler. and Rhizoglomus intraradices (N.C. Schenck and ...

  8. Studying genome heterogeneity within the arbuscular mycorrhizal fungal cytoplasm

    NARCIS (Netherlands)

    Boon, E.; Halary, S.; Bapteste, E.; Hijri, M.

    2015-01-01

    Although heterokaryons have been reported in nature, multicellular organisms are generally assumed genetically homogeneous. Here, we investigate the case of arbuscular mycorrhizal fungi (AMF) that form symbiosis with plant roots. The growth advantages they confer to their hosts are of great

  9. Arbuscular mycorrhizal fungi species associated with rhizosphere of ...

    African Journals Online (AJOL)

    A survey of arbuscular mycorrhizal fungi (AMF) diversity and date palm (Phoenix dactylifera L.) tree root colonization in arid areas was undertaken in ten palm groves located along the Ziz valley (Tafilalet, south-west Morocco). The frequency and the mean intensity of root colonization reached 72 and 43% respectively and ...

  10. Cover cropping impacts on arbuscular mycorrhizal fungi and soil aggregation

    Science.gov (United States)

    Cover crops are a management tool which can extend the period of time that a living plant is growing and conducting photosynthesis. This is critical for soil health, because most of the soil organisms, particularly the arbuscular mycorrhizal fungi, are limited by carbon. Research, on-farm, and demon...

  11. Phosphorus and Nitrogen Regulate Arbuscular Mycorrhizal Symbiosis in Petunia hybrida

    Science.gov (United States)

    Nouri, Eva; Breuillin-Sessoms, Florence; Feller, Urs; Reinhardt, Didier

    2014-01-01

    Phosphorus and nitrogen are essential nutrient elements that are needed by plants in large amounts. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. On the other hand, these nutrients influence root colonization by mycorrhizal fungi and symbiotic functioning. This represents a feedback mechanism that allows plants to control the fungal symbiont depending on nutrient requirements and supply. Elevated phosphorus supply has previously been shown to exert strong inhibition of arbuscular mycorrhizal development. Here, we address to what extent inhibition by phosphorus is influenced by other nutritional pathways in the interaction between Petunia hybrida and R. irregularis. We show that phosphorus and nitrogen are the major nutritional determinants of the interaction. Interestingly, the symbiosis-promoting effect of nitrogen starvation dominantly overruled the suppressive effect of high phosphorus nutrition onto arbuscular mycorrhiza, suggesting that plants promote the symbiosis as long as they are limited by one of the two major nutrients. Our results also show that in a given pair of symbiotic partners (Petunia hybrida and R. irregularis), the entire range from mutually symbiotic to parasitic can be observed depending on the nutritional conditions. Taken together, these results reveal complex nutritional feedback mechanisms in the control of root colonization by arbuscular mycorrhizal fungi. PMID:24608923

  12. Arbuscular mycorrhizal fungi improve the growth of olive trees and ...

    African Journals Online (AJOL)

    Two native Algerian mycorrhizal fungi (Glomus mosseae and Glomus intraradices) were tested for their effect on the growth of micropropagated olive tree (Olea europaea L.). The effect of inoculation of plantlets with G. mosseae was also compared with chemical fertilization using osmocote. Specific molecular techniques ...

  13. Influence of mycorrhizal inoculation on alley cropped farms in a ...

    African Journals Online (AJOL)

    The use of Arbuscular mycorrhizal (AM) fungi under farmers' conditions was tried at Ajibode Village, a humid tropical environment on maize/cassava intercropped farms in an alley cropping system. Four species of AM fungi (Glomus clarum, Glomus mosseae Glomus etunicatum and Acaulospora dilatata) were used in ...

  14. Mycorrhizal association in soybean and weeds in competition

    Directory of Open Access Journals (Sweden)

    Cíntia Maria Teixeira Fialho

    2016-04-01

    Full Text Available The purpose of this study was to evaluate the effects of mycorrhizal association on the interference of Bidens pilosa, Urochloa decumbens and Eleusine indica on soybean culture in two conditions: a plants competing without contact with roots of another species; b with contact between roots. At 60 days after planting, growth, nutrient accumulation and mycorrhizal colonization of soybean and weeds were evaluated. The contact between roots of soybean plant and weed species increased the negative interference effects for both species, with less growth and nutrient accumulation. With the individualization of roots, higher competition occurred for soil resources up to 60 days of coexistence between species. In competition with soybean, Bidens pilosa and Urochloa decumbens stood out in accumulation of most nutrients without differing from when cultivated in monocultivation. The increase of the soybean mycorrhizal colonization was 53, 40 and 33% when in competition with Urochloa decumbens, Eleusine indica and Bidens pilosa species, respectively. A positive interaction occurred for soybean mycorrhizal colonization and competing plants irrespective of weed species or root contact.

  15. The distribution of vesicular-arbuscular mycorrhizal fungi in India.

    Science.gov (United States)

    Rani, R; Mukerji, K G

    1990-01-01

    Vesicular-arbuscular mycorrhizal fungi are widely distributed throughout the area studied including different altitudes ranging from sea level to 2500 ft above sea level. VAM fungi were recorded from 88% of the sites examined with Glomus fasciculatum and Glomus macrocarpum being the most commonly recorded. Mean species diversity was found to be maximum in the areas thickly vegetated and undisturbed.

  16. Arbuscular mycorrhizal fungi improve the growth of olive trees and ...

    African Journals Online (AJOL)

    STORAGESEVER

    quality olive plants. To study the potential of the mycorrhizal fungi Glomus mosseae and Glomus intraradices to stimulate the growth of micropropagated olive plants and to compare their ... phosphate, 15% potassium oxide, 2% magnesium oxide, 4.5% sulphur, 0.02% ..... Our results indicate the feasibility of G. mosseae and.

  17. Phosphorus and nitrogen regulate arbuscular mycorrhizal symbiosis in Petunia hybrida.

    Science.gov (United States)

    Nouri, Eva; Breuillin-Sessoms, Florence; Feller, Urs; Reinhardt, Didier

    2014-01-01

    Phosphorus and nitrogen are essential nutrient elements that are needed by plants in large amounts. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. On the other hand, these nutrients influence root colonization by mycorrhizal fungi and symbiotic functioning. This represents a feedback mechanism that allows plants to control the fungal symbiont depending on nutrient requirements and supply. Elevated phosphorus supply has previously been shown to exert strong inhibition of arbuscular mycorrhizal development. Here, we address to what extent inhibition by phosphorus is influenced by other nutritional pathways in the interaction between Petunia hybrida and R. irregularis. We show that phosphorus and nitrogen are the major nutritional determinants of the interaction. Interestingly, the symbiosis-promoting effect of nitrogen starvation dominantly overruled the suppressive effect of high phosphorus nutrition onto arbuscular mycorrhiza, suggesting that plants promote the symbiosis as long as they are limited by one of the two major nutrients. Our results also show that in a given pair of symbiotic partners (Petunia hybrida and R. irregularis), the entire range from mutually symbiotic to parasitic can be observed depending on the nutritional conditions. Taken together, these results reveal complex nutritional feedback mechanisms in the control of root colonization by arbuscular mycorrhizal fungi.

  18. Mycorrhizal association of some agroforestry tree species in two ...

    African Journals Online (AJOL)

    Administrator

    2011-05-05

    May 5, 2011 ... Key words: Arbuscular mycorrhizal fungi, agroforestry tree species. INTRODUCTION ... plant growth hormones, protection of host roots from pathogens .... interactions between fungal strains and soil than between the fungus ... phosphorus and drought stress on the growth of Acacic nilotica and. Leucaena ...

  19. Mycorrhizal symbioses of Salix repens : diversity and functional significance

    NARCIS (Netherlands)

    Heijden, van der E.W.

    2000-01-01

    This thesis investigates the significance of different mycorrhizal fungi, belonging to different functional types (arbuscular mycorrhiza-AM and ectomycorrhiza-EcM), in Salix repens . A comparison between above-ground and below-ground observations on ectomycorrhizal

  20. Siderophore production by mycorrhizal sorghum roots under micronutrient deficient condition

    Directory of Open Access Journals (Sweden)

    N. Aliasgharzad

    2009-05-01

    Full Text Available It has widely been accepted that mycorrhizal symbiosis improves micronutrients uptake by most of the plants. In this study, sorghum (Sorghum bicolor L. plants were grown in sterile perlite and were inoculated with either Glomus etunicatum (GE or G.intraradices (GI, while the control set was left un-inoculated. Rorison's nutrient solution with three levels of 0, half and full strength (C0, C0.5 and C1, respectively of Fe, Cu, Zn and Mn was applied to the pots during 85 days of growth period. Chrome azurol-S assay was used for determination of siderophores in root leachates on 45, 65 and 85 days after sowing (DAS. Siderophore production per unit volume of root was higher in mycorrhizal than non-mycorrhizal plants. Both GE and GI were efficient fungi in this respect. Siderophore production was significantly induced at C0 level of the micronutrients. Amount of siderophores produced on 45 and 85 DAS was more than 65 DAS. Mycorrhizal root colonization by GE or GI was not significantly affected by micronutrient levels.

  1. Shoot- and root-borne cytokinin influences arbuscular mycorrhizal symbiosis

    NARCIS (Netherlands)

    Rebeca Cosme, M.P.

    2016-01-01

    The arbuscular mycorrhizal (AM) symbiosis is functionally important for the nutrition and growth of most terrestrial plants. Nearly all phytohormones are employed by plants to regulate the symbiosis with AM fungi, but the regulatory role of cytokinin (CK) is not well understood. Here, we used

  2. Reciprocal rewards stabilize cooperation in the mycorrhizal symbiosis

    NARCIS (Netherlands)

    Kiers, E.T.; Duhamel, M.; Beesetty, Y.; Mensah, J.A.; Franken, O.; Verbruggen, E.; Fellbaum, C.R.; Kowalchuk, G.A.; Hart, M.M.; Bago, A.; Palmer, T.M.; West, S.A.; Vandenkoornhuyse, P.; Jansa, J.; Bücking, H.

    2011-01-01

    Plants and their arbuscular mycorrhizal fungal symbionts interact in complex underground networks involving multiple partners. This increases the potential for exploitation and defection by individuals, raising the question of how partners maintain a fair, two-way transfer of resources. We

  3. 1000-kVA arc power supply

    International Nuclear Information System (INIS)

    Wright, R.E.; Barber, G.C.; Ponte, N.S.

    1979-01-01

    Because of ever-increasing power demands for the development of the Oak Ridge duoPIGatron ion source, a continuous-duty arc power supply was constructed for the Medium Energy Test Facility (METF) to furnish power for the plasma generator of experimental ion sources. The power supply utilizes 12-pulse rectification with half-wave switching in a delta and wye full-wave bridge that may be connected in series or parallel. It will deliver 340 V dc, 2500 A to an ion source when series connected and 170 V dc, 5000 A when paralleled connected. Silicon-controlled rectifiers (SCR) in each rectifier bridge can be switched for pulses as short as 10 ms through continuous duty. The filter section that reduces the ripple in the output consists of an inductor-to-capacitor (L-C) filter to smooth the 720-Hz pulses. The power transformer serves as an isolation transformer allowing the secondary to be elevated to the accelerating potential of the ion source. The dc output level is controlled with a 1000-kVA auto transformer connected to the primary of the power transformer. All elevated voltages and currents are monitored at ground potential with an optical telemetry system. This paper describes the power supply in detail, including block diagrams, component specifications, and waveforms when supplying power to an ion source

  4. COPD, COOP and BREATH at the VA

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2011-02-01

    Full Text Available No abstract available. Article truncated at 150 words. The February 2011 Pulmonary Journal Club reviews a study by Rice and colleagues (1 of high-risk COPD patients (click here for Pulmonary Journal Club. This review was authored by Kevin Park who also authored an ACP Journal Club review (2. In Rice’s study a single educational session, an individualized care plan, and monthly case-manager telephone calls, resulted in a 41% decrease in hospitalizations and emergency room visits and a nonsignficant trend toward decreased mortality.Rice’s study was supported and conducted in the Veterans Integrated Service Network (VISN 23 (Minnesota, Iowa, Nebraska and the Dakotas. The COPD patients in this study were recruited and followed primarily using the VA computer system. The study represents a potential model of data-based management leading to improved patient outcomes. The authors; Robert Petzel MD, then VISN 23 Director (now Veterans Healthcare Administration Undersecretary; and Janet Murphy, then VISN Primary Care Service Line CEO (now VISN …

  5. 76 FR 40453 - Agency Information Collection (Application for VA Education Benefits) Activity Under OMB Review

    Science.gov (United States)

    2011-07-08

    ... (Application for VA Education Benefits) Activity Under OMB Review AGENCY: Veterans Benefits Administration... Education Benefits, VA Form 22-1990. b. Application for Family Member to Use Transferred Benefits, VA Form 22-1990E. [[Page 40454

  6. VA INFORMATION SYSTEMS: Computer Security Weaknesses Persist at the Veterans Health Administration

    National Research Council Canada - National Science Library

    2000-01-01

    .... To determine the status of computer security within VHA, we (1) evaluated information system general controls at the VA Maryland Health Cafe System, the New Mexico VA Health Care System, and the VA North Texas Health Care System and (2...

  7. Revegetation of oil sands tailings. Growth improvement of silver-berry and buffalo-berry by inoculation with mycorrhizal fungi and N/sub 2/-fixing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Visser, S.; Danielson, R.M.

    1988-01-01

    The ability of actinorhizal shrubs to tolerate inhospitable conditions while improving soil fertility and organic matter status has led to increased usage of these plants for land reclamation and amenity planting purposes. Silver-berry and buffalo-berry are two such shrubs being tested as potential candidates for the revegetation of the oil sands tailings in northeastern Alberta. Associated with the roots of silver-berry and buffalo-berry are two symbiants, the N/sub 2/-fixing actimomycete Frankia and the vesicular-arbuscular mycorrhizal (VAM) fungi. Numerous studies have demonstrated that, particularly in nutrient-limited conditions, mycorrhization and nodulation can result in significantly better plant performance as a consequence of improved N and P nutrition. It was found in this study that in Alberta, silver-berry and buffalo-berry are strictly VA mycorrhizal; that they are highly dependent on their symbiants for optimum growth; and that the VAM inoculum potential of both stockpiled and undisturbed muskeg peak is negligible, due to the absence of VAM hosts. Means to increase the inoculum potential of peat have been studied. The efficacy of inoculating seedlings grown in greenhouses with VAM and Frankia has been demonstrated. Overwinter mortality was higher for inoculated shrubs, but after one growing season, shoot-weights of silver-berry were 3 to 7 times greater than for uninoculated shrubs, and shoot weights of buffalo-berry were 3 to 5 times greater. 122 refs., 12 figs., 31 tabs.

  8. Differences in Arbuscular Mycorrhizal Fungi among Three Coffee Cultivars in Puerto Rico

    OpenAIRE

    Lebrón, Ligia; Lodge, D. Jean; Bayman, Paul

    2012-01-01

    Mycorrhizal symbiosis is important for growth of coffee (Coffea arabica), but differences among coffee cultivars in response to mycorrhizal interactions have not been studied. We compared arbuscular mycorrhizal (AM) extraradical hyphae in the soil and diversity of AM fungi among three coffee cultivars, Caturra, Pacas, and Borbón, at three farms in Puerto Rico. Caturra had significantly lower total extraradical AM hyphal length than Pacas and Borbón at all locations. P content did not differ a...

  9. On the perils of mycorrhizal status lists: the case of Buddleja davidii.

    Science.gov (United States)

    Dickie, I A; Thomas, M M; Bellingham, P J

    2007-11-01

    One observation in a mycorrhizal check-list that Buddleja davidii is nonmycorrhizal has been perpetuated in subsequent citations and used in a number of analyses of mycorrhizal ecology and evolution. Direct observation of B. davidii from New Zealand and the UK shows extensive arbuscular mycorrhizal fungal structures inside B. davidii roots. The suggestion that B. davidii is nonmycorrhizal is therefore not supported. The use of mycorrhizal checklists for analysis of plant traits and evolution needs to be undertaken with care to ensure the validity of underlying data.

  10. Influence of arbuscular mycorrhizal fungus Glomus intraradices on accumulation of radiocaesium by plant species

    International Nuclear Information System (INIS)

    Dubchak, S.V.

    2012-01-01

    The role of arbuscular mycorrhizal fungus Glomus intraradices in 134 Cs isotope by different plant species is studied. The impact of radiocaesium on mycorrhizal development and functioning of plant photosynthetic apparatus is considered. The possibility of mycorrhizal symbiosis application in phyto remediation of radioactively contaminated areas is analyzed. It is found that colonization pf plants with arbuscular mycorrhizal fungus resulted in significant decrease of radiocesium concentration in their aboveground parts, while it did not have considerable impact on the radionuclide uptake by plant root system

  11. Influence of arbuscular mycorrhizal fungus Glomus intra-radices on accumulation of radiocaesium by plant species

    International Nuclear Information System (INIS)

    Dudchak, S.V.

    2012-01-01

    The role of arbuscular mycorrhizal fungus Glomus intra-radices in 134 Cs isotope uptake by different plant species is studied. The impact of radiocaesium on mycorrhizal development and functioning of plant photosynthetic apparatus is considered. The possibility of mycorrhizal symbiosis application in phytoremediation of radioactively contaminated areas is analyzed.It is found that colonization of plants with arbuscular mycorrhizal fungus resulted in significant decrease of radiocaesium concentration in their aboveground parts, while it did not have considerable impact on the radionuclide uptake by plant root system

  12. SlaVaComp: Konvertierungstool (= SlaVaComp Fonts Converter

    Directory of Open Access Journals (Sweden)

    Simon Skilevic

    2013-12-01

    Full Text Available Der vorliegende Beitrag informiert über ein Tool, das im Rahmen eines Freiburger Projekts zur historischen Korpuslinguistik entwickelt wurde und dazu dient, kirchenslavische Texte, die ohne Einsatz von Unicode digitalisiert wurden, ohne Verlust von Information bzw. Formatierung ins Unicode-Format zu überführen. Das Tool heißt SlaVaComp-Konvertierer. Es eignet sich für die Konvertierung aller idiosynkratischen Fonts und kann somit nicht nur in der Paläoslavistik, sondern in allen historisch arbeitenden Philologien eingesetzt werden. ____________________ This paper presents a fonts converter that was developed as a part of the Freiburg project on historical corpus linguistics. The tool named SlaVaComp-Konvertierer converts Church Slavonic texts digitized with non-Unicode fonts into the Unicode format without any loss of information contained in the original file and without damage to the original formatting. It is suitable for the conversion of all idiosyncratic fonts—not only Church Slavonic—and therefore can be used not only in Palaeoslavistic, but also in all historical and philological studies.

  13. An academic-VA partnership: Student interprofessional teams integrated with VA PACT teams.

    Science.gov (United States)

    Swenty, Constance L; Schaar, Gina L; Butler, Ryan M

    2016-12-01

    Veterans are challenged with multiple unique healthcare issues related to their military service environment. Likewise, health care providers must understand the special concerns associated with military conflict and recognize how the veteran's care can be optimized by interprofessional care delivery. Little is taught didactically or clinically that supports nursing students in addressing the unique issues of the veteran or the student's need to work collaboratively with allied health team members to enhance the veteran's care. Because of limited exposure to the veteran's special conditions, nursing students who may seek a career with the veteran population often face challenges in rendering appropriate care. The VA offers an invaluable opportunity for health profession students to collaborate with VA interprofessional Patient Aligned Care Teams (PACT) ultimately optimizing veteran health outcomes. This academic partnership, that implements an interprofessional model, will prepare students to better embrace the veteran population. This article describes the immersion of health profession students in interprofessional collaborative practice (IPCP) using PACT team principles which ultimately promotes the students' ability to link theory content to patient care delivery. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Maximum power per VA control of vector controlled interior ...

    Indian Academy of Sciences (India)

    Thakur Sumeet Singh

    2018-04-11

    Apr 11, 2018 ... Department of Electrical Engineering, Indian Institute of Technology Delhi, New ... The MPVA operation allows maximum-utilization of the drive-system. ... Permanent magnet motor; unity power factor; maximum VA utilization; ...

  15. VA Enterprise Design Patterns - 5.1 (Mobility) Mobile

    Data.gov (United States)

    Department of Veterans Affairs — First of a set of guidance documents that establish the architectural foundation for mobile computing in the VA. This document outlines the enterprise capabilities...

  16. VA Enterprise Design Patters - 2.5 (Enterprise Architecture)

    Data.gov (United States)

    Department of Veterans Affairs — Enterprise architectural guidelines and constraints that provide references to the use of enterprise capabilities that will enable the VA to access and exchange data...

  17. Whistle-blower accuses VA inspector general of a "whitewash"

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-09-01

    Full Text Available No abstract available. Article truncated after 150 words. Yesterday, Dr. Sam Foote, the initial whistle-blower at the Phoenix VA, criticized the Department of Veterans Affairs inspector general's (VAOIG report on delays in healthcare at the Phoenix VA at a hearing before the House Committee of Veterans Affairs (1,2. Foote accused the VAOIG of minimizing bad patient outcomes and deliberately confusing readers, downplaying the impact of delayed health care at Phoenix VA facilities. "At its best, this report is a whitewash. At its worst, it is a feeble attempt at a cover-up," said Foote. Foote earlier this year revealed that as many as 40 Phoenix patients died while awaiting care and that the Phoenix VA maintained secret waiting lists while under-reporting patient wait times for appointments. His disclosures triggered the national VA scandal. Richard Griffin, the acting VAOIG, said that nearly 300 patients died while on backlogged wait lists in the Phoenix VA Health Care System, a much higher ...

  18. Leaf elemental analysis in mycorrhizal post oak seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Boling, B.C. [Department of Biology, University of North Texas, P.O. Box 305220, Denton, TX 76203-5220 (United States); Naab, F.U. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, P.O. Box 311427, Denton, TX 76203-1427 (United States)]. E-mail: fun001@unt.edu; Smith, D. [Department of Biology, University of North Texas, P.O. Box 305220, Denton, TX 76203-5220 (United States); Duggan, J.L. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, P.O. Box 311427, Denton, TX 76203-1427 (United States); McDaniel, F.D. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, P.O. Box 311427, Denton, TX 76203-1427 (United States)

    2006-09-15

    Growth and element assimilation was investigated in the leaves of post oak seedlings exposed to four different treatment combinations of fertilization and ectomycorrhizal inoculation. Element concentration was analyzed via particle-induced X-ray emission spectrometry (PIXE). PIXE detected 10 of the 13 essential macro and micronutrients: P, S, Mg, Ca, K, Cu, Zn, Mn, Fe and Cl. Mean growth and dry weight was significantly different across the treatment groups as well as the mean concentration of Mg, Al, S, K, Ca, Fe, Cu and Zn. The data suggest that fertilization rather than mycorrhizal inoculation had a stronger influence on nutrient uptake. This study is the first to analyze element concentration in post oak and to investigate the potential benefits of mycorrhizal symbiosis in post oak seedlings in terms of nutrient uptake.

  19. The Role of Mycorrhizal Fungi in Ecosystem Energetics.

    Science.gov (United States)

    1982-03-01

    do not pene- trate the stele . They are the main organ of exchange between the plant and the mycorrhizal fungus. Intercellular hyphae are in direct...processes. Energy flow through the grazing and detritus pathways involves bio - chemical transformation of photosynthate to cellular biomass within...seedlings. 3. Measurement of Annual Production of Aboveground Plant Production and Partitioning Between Stems, Needles, and Branches. Volumes of bio - mass

  20. Arbuscular Mycorrhizal Symbiosis Alleviates Diesel Toxicity on Melilotus albus

    International Nuclear Information System (INIS)

    Hernandez-Ortega, H. A.; Alarcon, A.; Ferrera-Cerrato, R.; Zavaleta-Mancera, H. A.

    2009-01-01

    Petroleum hydrocarbons (PH) affect plant growth and development by limiting water absorption and nutrient availability. Arbuscular mycorrhizal fungi (AMF) have been demonstrated to increase plant tolerance of grass species to PH, but the performance of AMF on legume species during phytorremediation of PH-contaminated soils has been scarcely understood. Thus, this research evaluated the effects of AMF on tolerance and growth of Melilotus albus in a diesel-contaminated soil. (Author)

  1. Arbuscular Mycorrhizal Symbiosis Alleviates Diesel Toxicity on Melilotus albus

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Ortega, H. A.; Alarcon, A.; Ferrera-Cerrato, R.; Zavaleta-Mancera, H. A.

    2009-07-01

    Petroleum hydrocarbons (PH) affect plant growth and development by limiting water absorption and nutrient availability. Arbuscular mycorrhizal fungi (AMF) have been demonstrated to increase plant tolerance of grass species to PH, but the performance of AMF on legume species during phytorremediation of PH-contaminated soils has been scarcely understood. Thus, this research evaluated the effects of AMF on tolerance and growth of Melilotus albus in a diesel-contaminated soil. (Author)

  2. 75 FR 9277 - Proposed Information Collection (VA National Rehabilitation Special Events, Event Registration...

    Science.gov (United States)

    2010-03-01

    ... Sports Clinic Application, VA Form 0924--233 hours. b. National Veterans Wheelchair Games Application, VA.... National Veterans TEE Tournament Application, VA Form 0927--133 hours. e. National Veterans Summer Sports... Form 0929--67 hours. OMB Control Number: 2900-New (VA Form 0924). Type of Review: Existing collection...

  3. Cell wall remodeling in mycorrhizal symbiosis: a way towards biotrophism.

    Science.gov (United States)

    Balestrini, Raffaella; Bonfante, Paola

    2014-01-01

    Cell walls are deeply involved in the molecular talk between partners during plant and microbe interactions, and their role in mycorrhizae, i.e., the widespread symbiotic associations established between plant roots and soil fungi, has been investigated extensively. All mycorrhizal interactions achieve full symbiotic functionality through the development of an extensive contact surface between the plant and fungal cells, where signals and nutrients are exchanged. The exchange of molecules between the fungal and the plant cytoplasm takes place both through their plasma membranes and their cell walls; a functional compartment, known as the symbiotic interface, is thus defined. Among all the symbiotic interfaces, the complex intracellular interface of arbuscular mycorrhizal (AM) symbiosis has received a great deal of attention since its first description. Here, in fact, the host plasma membrane invaginates and proliferates around all the developing intracellular fungal structures, and cell wall material is laid down between this membrane and the fungal cell surface. By contrast, in ectomycorrhizae (ECM), where the fungus grows outside and between the root cells, plant and fungal cell walls are always in direct contact and form the interface between the two partners. The organization and composition of cell walls within the interface compartment is a topic that has attracted widespread attention, both in ecto- and endomycorrhizae. The aim of this review is to provide a general overview of the current knowledge on this topic by integrating morphological observations, which have illustrated cell wall features during mycorrhizal interactions, with the current data produced by genomic and transcriptomic approaches.

  4. Biodegradation of polycyclic aromatic hydrocarbons by arbuscular mycorrhizal leek plants

    International Nuclear Information System (INIS)

    Liu, A.; Dalpe, Y.

    2005-01-01

    A study was conducted to examine the response of arbuscular mycorrhizal fungi (AMF) on the degradation of polycyclic aromatic hydrocarbon (PAH), nutrient uptake, and leek growth under greenhouse conditions. This experiment included 3 mycorrhizal treatments, 2 microorganism treatments, 2 PAH chemicals, and 4 concentrations of PAHs. Plant growth was greatly reduced by the addition of anthracene or phenanthrene in soil, whereas mycorrhizal inoculation not only increased plant growth, but also enhanced uptake of nitrogen and phosphorus. PAH concentrations in soil was lowered through the inoculation of two different strains of the species G. intraradices and G. versiforme. In 12 weeks of pot cultures, anthracene and phenanthrene concentrations decreased for all 3 PAH levels tested. However, the reduced amount of phenanthrene in soil was greater than that of anthracene. The addition of a soil microorganism extract into pot cultures accelerated the PAH degradation. The inoculation of AMF in a hydrocarbon contaminated soil was shown to enhance PAHs soil decontamination. It was concluded that a soil colonized with AMF can not only improve plant growth but can also stimulate soil microflora abundance and diversity. AMF may therefore directly influence PAH soil decontamination through plant growth enhancement

  5. Interplant communication of tomato plants through underground common mycorrhizal networks.

    Science.gov (United States)

    Song, Yuan Yuan; Zeng, Ren Sen; Xu, Jian Feng; Li, Jun; Shen, Xiang; Yihdego, Woldemariam Gebrehiwot

    2010-10-13

    Plants can defend themselves to pathogen and herbivore attack by responding to chemical signals that are emitted by attacked plants. It is well established that such signals can be transferred through the air. In theory, plants can also communicate with each other through underground common mycorrhizal networks (CMNs) that interconnect roots of multiple plants. However, until now research focused on plant-to-plant carbon nutrient movement and there is no evidence that defense signals can be exchanged through such mycorrhizal hyphal networks. Here, we show that CMNs mediate plant-plant communication between healthy plants and pathogen-infected tomato plants (Lycopersicon esculentum Mill.). After establishment of CMNs with the arbuscular mycorrhizal fungus Glomus mosseae between tomato plants, inoculation of 'donor' plants with the pathogen Alternaria solani led to increases in disease resistance and activities of the putative defensive enzymes, peroxidase, polyphenol oxidase, chitinase, β-1,3-glucanase, phenylalanine ammonia-lyase and lipoxygenase in healthy neighbouring 'receiver' plants. The uninfected 'receiver' plants also activated six defence-related genes when CMNs connected 'donor' plants challenged with A. solani. This finding indicates that CMNs may function as a plant-plant underground communication conduit whereby disease resistance and induced defence signals can be transferred between the healthy and pathogen-infected neighbouring plants, suggesting that plants can 'eavesdrop' on defence signals from the pathogen-challenged neighbours through CMNs to activate defences before being attacked themselves.

  6. arbuscular mycorrhizal fungi status of some crops in the cross river ...

    African Journals Online (AJOL)

    PROF EKWUEME

    The incidence of arbuscular mycorrhizal fungi (AMF) colonization and rhizospheric spore prevalence of ten crops was studied in relation to their foliar concentration of nitrogen, phosphorus and potassium in the Calabar area of the Cross. River Basin of Nigeria in order to determine their mycorrhizal status. All crops studied ...

  7. Role of mycorrhizal fungi and salicylic acid in salinity tolerance of ...

    African Journals Online (AJOL)

    Most researchers showed that inoculation of plants with mycorrhizal fungi and using salicylic acid increase tolerance of plants due to salinity. In this study, the effect of mycorrhizal fungi, including Glomus mosseae, Glomus intraradices, and salicylic acid (0.2 mM) on tolerance of green basil (Ocimum basilicum L.) to salinity ...

  8. Mycorrhizal diversity of stevia (Stevia rebaudiana Bertoni) rhizosphere in Tawangmangu, Indonesia

    Science.gov (United States)

    Astuti, D. Y.; Parjanto; Cahyani, V. R.

    2018-03-01

    Mycorrhizal fungi is a group of soil fungi with mutualistic symbiosis between fungi and plant roots. The diversity on mycorrhiza contributes the maintenance of plant biodiversity, ecosystem function, and plant productivity. Climate change may affects the distribution and diversity of mycorrhizal fungi, and thus the study on mycorrhizal diversity is important to develop the information about mycorrhizal function and utilization. The present study investigated mycorrhizal diversity in the rhizosphere of stevia at four locations in different altitudes and soil types. The samples taken from Tlogodlingo (Andisols 1), Kalisoro (Andisols 2), Nglurah (Alfisols 1) and Ledoksari (Alfisols 2) in Tawangmangu, Karanganyar, Central Java, Indonesia. The result showed that Glomus sp. and Acaulospora sp. were the common genus found at all locations, whereas Gigaspora sp. was the only species found in the acidic Alfisol soil. Statistical analysis indicated that altitude, soil pH, and P availability significantly positively correlated with mycorrhizal spore density. The increase of altitude, soil pH and P availability, also increase the mycorrhizal spore density. Mycorrhizal infectivity negatively correlated with C/N ratio.

  9. Arbuscular Mycorrhizal Symbiosis Modulates Antioxidant Response and Ion Distribution in Salt-Stressed Elaeagnus angustifolia Seedlings

    Directory of Open Access Journals (Sweden)

    Wei Chang

    2018-04-01

    Full Text Available Elaeagnus angustifolia L. is a drought-resistant species. Arbuscular mycorrhizal symbiosis is considered to be a bio-ameliorator of saline soils that can improve salinity tolerance in plants. The present study investigated the effects of inoculation with the arbuscular mycorrhizal fungus Rhizophagus irregularis on the biomass, antioxidant enzyme activities, and root, stem, and leaf ion accumulation of E. angustifolia seedlings grown during salt stress conditions. Salt-stressed mycorrhizal seedlings produced greater root, stem, and leaf biomass than the uninoculated stressed seedlings. In addition, the seedlings colonized by R. irregularis showed notably higher activities of superoxide dismutase (SOD, catalase (CAT, and ascorbate peroxidase (APX in the leaves of the mycorrhizal seedlings in response to salinity compared to those of the non-mycorrhizal seedlings. Mycorrhizal seedlings not only significantly increased their ability to acquire K+, Ca2+, and Mg2+, but also maintained higher K+:Na+ ratios in the leaves and lower Ca2+:Mg2+ ratios than non-mycorrhizal seedlings during salt stress. These results suggest that the salt tolerance of E. angustifolia seedlings could be enhanced by R. irregularis. The arbuscular mycorrhizal symbiosis could be a promising method to restore and utilize salt-alkaline land in northern China.

  10. Arbuscular Mycorrhizal Symbiosis Modulates Antioxidant Response and Ion Distribution in Salt-Stressed Elaeagnus angustifolia Seedlings.

    Science.gov (United States)

    Chang, Wei; Sui, Xin; Fan, Xiao-Xu; Jia, Ting-Ting; Song, Fu-Qiang

    2018-01-01

    Elaeagnus angustifolia L. is a drought-resistant species. Arbuscular mycorrhizal symbiosis is considered to be a bio-ameliorator of saline soils that can improve salinity tolerance in plants. The present study investigated the effects of inoculation with the arbuscular mycorrhizal fungus Rhizophagus irregularis on the biomass, antioxidant enzyme activities, and root, stem, and leaf ion accumulation of E. angustifolia seedlings grown during salt stress conditions. Salt-stressed mycorrhizal seedlings produced greater root, stem, and leaf biomass than the uninoculated stressed seedlings. In addition, the seedlings colonized by R. irregularis showed notably higher activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) in the leaves of the mycorrhizal seedlings in response to salinity compared to those of the non-mycorrhizal seedlings. Mycorrhizal seedlings not only significantly increased their ability to acquire K + , Ca 2+ , and Mg 2+ , but also maintained higher K + :Na + ratios in the leaves and lower Ca 2+ :Mg 2+ ratios than non-mycorrhizal seedlings during salt stress. These results suggest that the salt tolerance of E. angustifolia seedlings could be enhanced by R. irregularis. The arbuscular mycorrhizal symbiosis could be a promising method to restore and utilize salt-alkaline land in northern China.

  11. Root-Associated Fungi Shared Between Arbuscular Mycorrhizal and Ectomycorrhizal Conifers in a Temperate Forest.

    Science.gov (United States)

    Toju, Hirokazu; Sato, Hirotoshi

    2018-01-01

    Arbuscular mycorrhizal and ectomycorrhizal symbioses are among the most important drivers of terrestrial ecosystem dynamics. Historically, the two types of symbioses have been investigated separately because arbuscular mycorrhizal and ectomycorrhizal plant species are considered to host discrete sets of fungal symbionts (i.e., arbuscular mycorrhizal and ectomycorrhizal fungi, respectively). Nonetheless, recent studies based on high-throughput DNA sequencing technologies have suggested that diverse non-mycorrhizal fungi (e.g., endophytic fungi) with broad host ranges play roles in relationships between arbuscular mycorrhizal and ectomycorrhizal plant species in forest ecosystems. By analyzing an Illumina sequencing dataset of root-associated fungi in a temperate forest in Japan, we statistically examined whether co-occurring arbuscular mycorrhizal ( Chamaecyparis obtusa ) and ectomycorrhizal ( Pinus densiflora ) plant species could share non-mycorrhizal fungal communities. Among the 919 fungal operational taxonomic units (OTUs) detected, OTUs in various taxonomic lineages were statistically designated as "generalists," which associated commonly with both coniferous species. The list of the generalists included fungi in the genera Meliniomyces, Oidiodendron, Cladophialophora, Rhizodermea, Penicillium , and Mortierella . Meanwhile, our statistical analysis also detected fungi preferentially associated with Chamaecyparis (e.g., Pezicula ) or Pinus (e.g., Neolecta ). Overall, this study provides a basis for future studies on how arbuscular mycorrhizal and ectomycorrhizal plant species interactively drive community- or ecosystem-scale processes. The physiological functions of the fungi highlighted in our host-preference analysis deserve intensive investigations for understanding their roles in plant endosphere and rhizosphere.

  12. Increasing diveristy of arbuscular mycorrhizal fungi in agroecosystems using specific cover crops

    Science.gov (United States)

    Fall-planted cover crops provide a plant host for obligate symbiotic arbuscular mycorrhizal fungi (AMF) during otherwise fallow periods and thus may increase AMF numbers in agroecosystems. Increased AMF numbers should increase mycorrhizal colonization of the subsequent cash crops, which has been li...

  13. Meta-analysis of crop and weed growth responses to arbuscular-mycorrhizal fungi

    Science.gov (United States)

    Arbuscular mycorrhizal fungi (AMF) have long been regarded as beneficial soil microorganisms, but have been reported to have detrimental effects on several non-mycorrhizal agricultural weed species. If AMF have negative effects on weeds but neutral or positive effects on crops under certain cropping...

  14. Arbuscular mycorrhizal fungi status of some crops in the cross river ...

    African Journals Online (AJOL)

    The incidence of arbuscular mycorrhizal fungi (AMF) colonization and rhizospheric spore prevalence of ten crops was studied in relation to their foliar concentration of nitrogen, phosphorus and potassium in the Calabar area of the Cross River Basin of Nigeria in order to determine their mycorrhizal status. All crops studied ...

  15. Resilience of arctic mycorrhizal fungal communities after wildfire facilitated by resprouting shrubs

    Science.gov (United States)

    Rebecca E. Hewitt; Elizabeth Bent; Teresa N. Hollingsworth; F. Stuart Chapin; D. Lee Taylor

    2013-01-01

    Climate-induced changes in the tundra fire regime are expected to alter shrub abundance and distribution across the Arctic. However, little is known about how fire may indirectly impact shrub performance by altering mycorrhizal symbionts. We used molecular tools, including ARISA and ITS sequencing, to characterize the mycorrhizal communities on resprouting ...

  16. Differences in mycorrhizal communities between Epipactis palustris, E. helleborine and its presumed sister species E. neerlandica

    OpenAIRE

    Jacquemyn, Hans; Waud, Michael; Lievens, Bart; Brys, Rein

    2016-01-01

    Background and Aims In orchid species that have populations occurring in strongly contrasting habitats, mycorrhizal divergence and other habitat-specific adaptations may lead to the formation of reproductively isolated taxa and ultimately to species formation. However, little is known about the mycorrhizal communities associated with recently diverged sister taxa that occupy different habitats.

  17. Phosphate uptake from phytate due to hyphae-mediated phytase activity by arbuscular mycorrhizal maize

    NARCIS (Netherlands)

    Wang, Xinxin; Hoffland, Ellis; Feng, Gu; Kuijper, Thomas

    2017-01-01

    Phytate is the most abundant form of soil organic phosphorus (P). Increased P nutrition of arbuscular mycorrhizal plants derived from phytate has been repeatedly reported. Earlier studies assessed acid phosphatase rather than phytase as an indication of mycorrhizal fungi-mediated phytate use. We

  18. 65Zn transfer in maize – Mycorrhizal system: mechanism to alleviate Zn deficiency

    International Nuclear Information System (INIS)

    Subramanian, K.S.; Tenshia, J.S. Virgine; Meena, S.

    2017-01-01

    Mycorrhizal symbiosis improves the host plant Zn nutrition as a consequence of hyphal transport, enhanced availability in soil as measured using isotopic dilution techniques besides preferential mobilization and transport of Zn. Overall, the data suggest that mycorrhizal symbiosis can improve the host plant nutrition and quality of grains through the mobilization and transport of slowly diffusing ions such as Zn

  19. A Role for Myosin Va in Human Cytomegalovirus Nuclear Egress.

    Science.gov (United States)

    Wilkie, Adrian R; Sharma, Mayuri; Pesola, Jean M; Ericsson, Maria; Fernandez, Rosio; Coen, Donald M

    2018-03-15

    Herpesviruses replicate and package their genomes into capsids in replication compartments within the nuclear interior. Capsids then move to the inner nuclear membrane for envelopment and release into the cytoplasm in a process called nuclear egress. We previously found that nuclear F-actin is induced upon infection with the betaherpesvirus human cytomegalovirus (HCMV) and is important for nuclear egress and capsid localization away from replication compartment-like inclusions toward the nuclear rim. Despite these and related findings, it has not been shown that any specific motor protein is involved in herpesvirus nuclear egress. In this study, we have investigated whether the host motor protein, myosin Va, could be fulfilling this role. Using immunofluorescence microscopy and coimmunoprecipitation, we observed associations between a nuclear population of myosin Va and the viral major capsid protein, with both concentrating at the periphery of replication compartments. Immunoelectron microscopy showed that nearly 40% of assembled nuclear capsids associate with myosin Va. We also found that myosin Va and major capsid protein colocalize with nuclear F-actin. Importantly, antagonism of myosin Va with RNA interference or a dominant negative mutant revealed that myosin Va is important for the efficient production of infectious virus, capsid accumulation in the cytoplasm, and capsid localization away from replication compartment-like inclusions toward the nuclear rim. Our results lead us to suggest a working model whereby human cytomegalovirus capsids associate with myosin Va for movement from replication compartments to the nuclear periphery during nuclear egress. IMPORTANCE Little is known regarding how newly assembled and packaged herpesvirus capsids move from the nuclear interior to the periphery during nuclear egress. While it has been proposed that an actomyosin-based mechanism facilitates intranuclear movement of alphaherpesvirus capsids, a functional role for

  20. Mycorrhizal symbionts of Pisonia grandis and P. sechellarum in Seychelles: identification of mycorrhizal fungi and description of new Tomentella species.

    Science.gov (United States)

    Suvi, Triin; Tedersoo, Leho; Abarenkov, Kessy; Beaver, Katy; Gerlach, Justin; Kõljalg, Urmas

    2010-01-01

    Nyctaginaceae includes species that are predominantly non-mycorrhizal or form arbuscular or ectomycorrhiza. Root-associated fungi were studied from P. grandis and P. sechellarum roots collected respectively on the islands of Cousin and Silhouette in Seychelles. In addition fungal sporocarps were collected from the sampling area. Fungal symbionts were identified from the roots by anatomotyping and rDNA sequencing; sporocarps collected were examined microscopically and sequenced. Three distantly related ectomycorrhizal fungal species belonging to Thelephoraceae were identified from the roots of P. grandis. Sporocarps also were found for two symbionts and described as new Tomentella species. In addition Tomentella species collected from other Seychelles islands were studied and described as new species if there was no close resemblance to previously established species. P. sechellarum was determined to be an arbuscular mycorrhizal plant; three arbuscular mycorrhizal fungal species were detected from the roots. P. grandis is probably associated only with species of Thelephoraceae throughout its area. Only five Tomentella species are known to form ectomycorrhiza with P. grandis and they never have been found to be associated with another host, suggesting adaptation of these fungi to extreme environmental conditions in host's habitat.

  1. Patient deaths blamed on long waits at the Phoenix VA

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-04-01

    Full Text Available No abstract available. Article truncated at 150 words. This morning the lead article in the Arizona Republic was a report blaming as many as 40 deaths at the Phoenix VA on long waits (1. Yesterday, Rep. Jeff Miller, the chairman of the House Committee on Veterans Affairs, held a hearing titled “A Continued Assessment of Delays in VA Medical Care and Preventable Veteran Deaths.” “It appears as though there could be as many as 40 veterans whose deaths could be related to delays in care,” Miller announced to a stunned audience. The committee has spent months investigating patient-care scandals and allegations at VA facilities in Pittsburgh, Atlanta, Miami and other cities. said that dozens of VA hospital patients in Phoenix may have died while awaiting medical care. He went on to say that staff investigators have evidence that the Phoenix VA Health Care System keeps two sets of records to conceal prolonged waits that patients must endure for ...

  2. Responses of mycorrhizal fungi and other rootassociated fungi to climate change

    DEFF Research Database (Denmark)

    Merrild, Marie Porret

    Climate change is expected to affect many terrestrial ecosystem processes. Mycorrhizal fungi are important to soil carbon (C) and nutrient cycling thus changes in abundance of mycorrhizal fungi could alter ecosystem functioning. The aim of the present thesis was therefore to investigate responses...... of mycorrhizal fungi to climate change in a seasonal and long-term perspective. Effects of elevated CO2 (510 ppm), night-time warming and extended summer drought were investigated in the long-term field experiment CLIMAITE located in a Danish semi-natural heathland. Mycorrhizal colonization was investigated...... levels. Colonization by arbuscular mycorrhizal (AM) fungi increased under elevated CO2 and warming in spring while ericoid mycorrhiza (ErM) colonisation decreased in response to drought and warming. Increased AM colonization correlated with higher phosphorus and nitrogen root pools. Dark septate...

  3. Role and influence of mycorrhizal fungi on radiocesium accumulation by plants

    International Nuclear Information System (INIS)

    Dupre de Boulois, H.; Joner, E.J.; Leyval, C.; Jakobsen, I.; Chen, B.D.; Roos, P.; Thiry, Y.; Rufyikiri, G.; Delvaux, B.; Declerck, S.

    2008-01-01

    This review summarizes current knowledge on the contribution of mycorrhizal fungi to radiocesium immobilization and plant accumulation. These root symbionts develop extended hyphae in soils and readily contribute to the soil-to-plant transfer of some nutrients. Available data show that ecto-mycorrhizal (ECM) fungi can accumulate high concentration of radiocesium in their extraradical phase while radiocesium uptake and accumulation by arbuscular mycorrhizal (AM) fungi is limited. Yet, both ECM and AM fungi can transport radiocesium to their host plants, but this transport is low. In addition, mycorrhizal fungi could thus either store radiocesium in their intraradical phase or limit its root-to-shoot translocation. The review discusses the impact of soil characteristics, and fungal and plant transporters on radiocesium uptake and accumulation in plants, as well as the potential role of mycorrhizal fungi in phytoremediation strategies

  4. [Discussion on appraisal methods and key technologies of arbuscular mycorrhizal fungi and medicinal plant symbiosis system].

    Science.gov (United States)

    Chen, Meilan; Guo, Lanping; Yang, Guang; Chen, Min; Yang, Li; Huang, Luqi

    2011-11-01

    Applications of arbuscular mycorrhizal fungi in research of medicinal plant cultivation are increased in recent years. Medicinal plants habitat is complicated and many inclusions are in root, however crop habitat is simple and few inclusions in root. So appraisal methods and key technologies about the symbiotic system of crop and arbuscular mycorrhizal fungi can't completely suitable for the symbiotic system of medicinal plants and arbuscular mycorrhizal fungi. This article discuss the appraisal methods and key technologies about the symbiotic system of medicinal plant and arbuscular mycorrhizal fungi from the isolation and identification of arbuscular mycorrhiza, and the appraisal of colonization intensity. This article provides guidance for application research of arbuscular mycorrhizal fungi in cultivation of medicinal plants.

  5. Role and influence of mycorrhizal fungi on radiocesium accumulation by plants

    Energy Technology Data Exchange (ETDEWEB)

    Dupre de Boulois, H. [Universite catholique de Louvain, Unite de Microbiologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium); Joner, E.J. [Bioforsk Soil and Environment, FredrikA Dahls vei 20, N-1432 As (Norway); Leyval, C. [LIMOS, Nancy University, CNRS, Faculte des Sciences, BP239, 54506 Vandoeuvre-les-Nancy, Cedex (France); Jakobsen, I. [Biosystems Department, Riso National Laboratory, Technical University of Denmark, DK-4000 Roskilde (Denmark); Chen, B.D. [Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Roos, P. [Radiation Research Department, Riso National Laboratory, Technical University of Denmark, DK-4000 Roskilde (Denmark); Thiry, Y.; Rufyikiri, G. [Biosphere Impact Assessment, SCK.CEN, Foundation of Public Utility, 200 Boeretang, 2400 Mol (Belgium); Delvaux, B. [Universite catholique de Louvain, Unite des Sciences du Sol, Croix du Sud 2/10, 1348 Louvain-la-Neuve (Belgium); Declerck, S. [Universite catholique de Louvain, Unite de Microbiologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium)], E-mail: declerck@mbla.ucl.ac.be

    2008-05-15

    This review summarizes current knowledge on the contribution of mycorrhizal fungi to radiocesium immobilization and plant accumulation. These root symbionts develop extended hyphae in soils and readily contribute to the soil-to-plant transfer of some nutrients. Available data show that ecto-mycorrhizal (ECM) fungi can accumulate high concentration of radiocesium in their extraradical phase while radiocesium uptake and accumulation by arbuscular mycorrhizal (AM) fungi is limited. Yet, both ECM and AM fungi can transport radiocesium to their host plants, but this transport is low. In addition, mycorrhizal fungi could thus either store radiocesium in their intraradical phase or limit its root-to-shoot translocation. The review discusses the impact of soil characteristics, and fungal and plant transporters on radiocesium uptake and accumulation in plants, as well as the potential role of mycorrhizal fungi in phytoremediation strategies.

  6. Host Plant Physiology and Mycorrhizal Functioning Shift across a Glacial through Future [CO2] Gradient.

    Science.gov (United States)

    Becklin, Katie M; Mullinix, George W R; Ward, Joy K

    2016-10-01

    Rising atmospheric carbon dioxide concentration ([CO 2 ]) may modulate the functioning of mycorrhizal associations by altering the relative degree of nutrient and carbohydrate limitations in plants. To test this, we grew Taraxacum ceratophorum and Taraxacum officinale (native and exotic dandelions) with and without mycorrhizal fungi across a broad [CO 2 ] gradient (180-1,000 µL L -1 ). Differential plant growth rates and vegetative plasticity were hypothesized to drive species-specific responses to [CO 2 ] and arbuscular mycorrhizal fungi. To evaluate [CO 2 ] effects on mycorrhizal functioning, we calculated response ratios based on the relative biomass of mycorrhizal (M Bio ) and nonmycorrhizal (NM Bio ) plants (R Bio = [M Bio - NM Bio ]/NM Bio ). We then assessed linkages between R Bio and host physiology, fungal growth, and biomass allocation using structural equation modeling. For T. officinale, R Bio increased with rising [CO 2 ], shifting from negative to positive values at 700 µL L -1 [CO 2 ] and mycorrhizal effects on photosynthesis and leaf growth rates drove shifts in R Bio in this species. For T. ceratophorum, R Bio increased from 180 to 390 µL L -1 and further increases in [CO 2 ] caused R Bio to shift from positive to negative values. [CO 2 ] and fungal effects on plant growth and carbon sink strength were correlated with shifts in R Bio in this species. Overall, we show that rising [CO 2 ] significantly altered the functioning of mycorrhizal associations. These symbioses became more beneficial with rising [CO 2 ], but nonlinear effects may limit plant responses to mycorrhizal fungi under future [CO 2 ]. The magnitude and mechanisms driving mycorrhizal-CO 2 responses reflected species-specific differences in growth rate and vegetative plasticity, indicating that these traits may provide a framework for predicting mycorrhizal responses to global change. © 2016 American Society of Plant Biologists. All Rights Reserved.

  7. VA's National PTSD Brain Bank: a National Resource for Research.

    Science.gov (United States)

    Friedman, Matthew J; Huber, Bertrand R; Brady, Christopher B; Ursano, Robert J; Benedek, David M; Kowall, Neil W; McKee, Ann C

    2017-08-25

    The National PTSD Brain Bank (NPBB) is a brain tissue biorepository established to support research on the causes, progression, and treatment of PTSD. It is a six-part consortium led by VA's National Center for PTSD with participating sites at VA medical centers in Boston, MA; Durham, NC; Miami, FL; West Haven, CT; and White River Junction, VT along with the Uniformed Services University of Health Sciences. It is also well integrated with VA's Boston-based brain banks that focus on Alzheimer's disease, ALS, chronic traumatic encephalopathy, and other neurological disorders. This article describes the organization and operations of NPBB with specific attention to: tissue acquisition, tissue processing, diagnostic assessment, maintenance of a confidential data biorepository, adherence to ethical standards, governance, accomplishments to date, and future challenges. Established in 2014, NPBB has already acquired and distributed brain tissue to support research on how PTSD affects brain structure and function.

  8. Poststroke Rehabilitation and Restorative Care Utilization: A Comparison Between VA Community Living Centers and VA-contracted Community Nursing Homes.

    Science.gov (United States)

    Jia, Huanguang; Pei, Qinglin; Sullivan, Charles T; Cowper Ripley, Diane C; Wu, Samuel S; Bates, Barbara E; Vogel, W Bruce; Bidelspach, Douglas E; Wang, Xinping; Hoffman, Nannette

    2016-03-01

    Effective poststroke rehabilitation care can speed patient recovery and minimize patient functional disabilities. Veterans affairs (VA) community living centers (CLCs) and VA-contracted community nursing homes (CNHs) are the 2 major sources of institutional long-term care for Veterans with stroke receiving care under VA auspices. This study compares rehabilitation therapy and restorative nursing care among Veterans residing in VA CLCs versus those Veterans in VA-contracted CNHs. Retrospective observational. All Veterans diagnosed with stroke, newly admitted to the CLCs or CNHs during the study period who completed at least 2 Minimum Data Set assessments postadmission. The outcomes were numbers of days for rehabilitation therapy and restorative nursing care received by the Veterans during their stays in CLCs or CNHs as documented in the Minimum Data Set databases. For rehabilitation therapy, the CLC Veterans had lower user rates (75.2% vs. 76.4%, P=0.078) and fewer observed therapy days (4.9 vs. 6.4, Pcare, CLC Veterans had higher user rates (33.5% vs. 30.6%, Pcare days (9.4 vs. 5.9, Pcare (coefficient=5.48±0.37, Pcare both before and after risk adjustment.

  9. VA Telemedicine: An Analysis of Cost and Time Savings.

    Science.gov (United States)

    Russo, Jack E; McCool, Ryan R; Davies, Louise

    2016-03-01

    The Veterans Affairs (VA) healthcare system provides beneficiary travel reimbursement ("travel pay") to qualifying patients for traveling to appointments. Travel pay is a large expense for the VA and hence the U.S. Government, projected to cost nearly $1 billion in 2015. Telemedicine in the VA system has the potential to save money by reducing patient travel and thus the amount of travel pay disbursed. In this study, we quantify this savings and also report trends in VA telemedicine volumes over time. All telemedicine visits based at the VA Hospital in White River Junction, VT between 2005 and 2013 were reviewed (5,695 visits). Travel distance and time saved as a result of telemedicine were calculated. Clinical volume in the mental health department, which has had the longest participation in telemedicine, was analyzed. Telemedicine resulted in an average travel savings of 145 miles and 142 min per visit. This led to an average travel payment savings of $18,555 per year. Telemedicine volume grew significantly over the study period such that by the final year the travel pay savings had increased to $63,804, or about 3.5% of the total travel pay disbursement for that year. The number of mental health telemedicine visits rose over the study period but remained small relative to the number of face-to-face visits. A higher proportion of telemedicine visits involved new patients. Telemedicine at the VA saves travel distance and time, although the reduction in travel payments remains modest at current telemedicine volumes.

  10. Reaction of mycorrhizal and non-mycorrhizal Scots pine fine roots along a deposition gradient of air pollutants in eastern Germany

    International Nuclear Information System (INIS)

    Muenzenberger, B.; Schminke, B.; Strubelt, F.; Huettl, R.F.

    1995-01-01

    Based on an ecosystematic approach within the comprehensive SANA (regeneration of the atmosphere above the new federal states) project the influence of industrial air pollutants (SO 2 , NO x ) (alkaline fly ashes) on the vitality of mycorrhizal, mycorrhizal frequency, and on parameters of root growth such as root biomass and necromass and distribution of different root classes in the soil horizons was investigated. The studies were conducted in three comparable Scots pine ecosystems in eastern Germany which were exposed to different deposition loads of air pollutants during the time of the former German Democratic Republic. Site specific differences were obtained for all parameters investigated. The reference plot Neuglobsow (background deposition) revealed the highest number of vital mycorrhizal, highest mycorrhizal frequency, and largest biomass of finest roots in the humus layer. At the impact-site Roesa and Taura (heavy and moderate deposition) located near Halle/Bitterfeld and Leipzig, the number of vital mycorrhizae was reduced and the life-span of mycorrhizae of reduced vitality was elongated. Finest root biomass and necromass of the humus layer were also lower at these plots as compared to Neuglobsow. At Neuglobsow a higher turnover of mycorrhizae and finest roots of the humus layer is assumed. The reduced growth of mycorrhizal and non-mycorrhizal finest roots at the two pollution impacted sites Roesa and Taura is seen as an adaptation mechanism of the root system to high nutrient inputs. 14 refs., 4 figs

  11. Weed control and cover crop management affect mycorrhizal colonization of grapevine roots and arbuscular mycorrhizal fungal spore populations in a California vineyard.

    Science.gov (United States)

    Baumgartner, Kendra; Smith, Richard F; Bettiga, Larry

    2005-03-01

    Arbuscular mycorrhizal (AM) fungi naturally colonize grapevines in California vineyards. Weed control and cover cropping may affect AM fungi directly, through destruction of extraradical hyphae by soil disruption, or indirectly, through effects on populations of mycorrhizal weeds and cover crops. We examined the effects of weed control (cultivation, post-emergence herbicides, pre-emergence herbicides) and cover crops (Secale cereale cv. Merced rye, x Triticosecale cv.Trios 102) on AM fungi in a Central Coast vineyard. Seasonal changes in grapevine mycorrhizal colonization differed among weed control treatments, but did not correspond with seasonal changes in total weed frequency. Differences in grapevine colonization among weed control treatments may be due to differences in mycorrhizal status and/or AM fungal species composition among dominant weed species. Cover crops had no effect on grapevine mycorrhizal colonization, despite higher spring spore populations in cover cropped middles compared to bare middles. Cover crops were mycorrhizal and shared four AM fungal species (Glomus aggregatum, G. etunicatum, G. mosseae, G. scintillans) in common with grapevines. Lack of contact between grapevine roots and cover crop roots may have prevented grapevines from accessing higher spore populations in the middles.

  12. The WHO 2016 verbal autopsy instrument: An international standard suitable for automated analysis by InterVA, InSilicoVA, and Tariff 2.0.

    Directory of Open Access Journals (Sweden)

    Erin K Nichols

    2018-01-01

    Full Text Available Verbal autopsy (VA is a practical method for determining probable causes of death at the population level in places where systems for medical certification of cause of death are weak. VA methods suitable for use in routine settings, such as civil registration and vital statistics (CRVS systems, have developed rapidly in the last decade. These developments have been part of a growing global momentum to strengthen CRVS systems in low-income countries. With this momentum have come pressure for continued research and development of VA methods and the need for a single standard VA instrument on which multiple automated diagnostic methods can be developed.In 2016, partners harmonized a WHO VA standard instrument that fully incorporates the indicators necessary to run currently available automated diagnostic algorithms. The WHO 2016 VA instrument, together with validated approaches to analyzing VA data, offers countries solutions to improving information about patterns of cause-specific mortality. This VA instrument offers the opportunity to harmonize the automated diagnostic algorithms in the future.Despite all improvements in design and technology, VA is only recommended where medical certification of cause of death is not possible. The method can nevertheless provide sufficient information to guide public health priorities in communities in which physician certification of deaths is largely unavailable. The WHO 2016 VA instrument, together with validated approaches to analyzing VA data, offers countries solutions to improving information about patterns of cause-specific mortality.

  13. [Physiological responses of mycorrhizal Pinus massoniana seedlings to drought stress and drought resistance evaluation].

    Science.gov (United States)

    Wang, Yi; Ding, Gui-jie

    2013-03-01

    A greenhouse pot experiment was conducted to study the effects of inoculating Pisolithus tinctorius, Cenococcum geophilum, Cantharellus cibarius, and Suillus luteus on the physiological characteristics of Pinus massoniana seedlings under the conditions of drought stress and re-watering, with the drought resistance of the mycorrhizal seedlings evaluated. Under drought stress, the MDA content and membrane' s relative permeability of P. massoniana seedlings increased, but these two indices in the inoculated (mycorrhizal) seedlings were significantly lower than these in the un-inoculated (control) seedlings. After re-watering, the MDA content and membrane's relative permeability of mycorrhizal seedlings had a rapid decrease, as compared with the control. In the first 21 days of drought stress, the production rate of superoxide radical of the seedlings increased, and the SOD, POD and NR activities of mycorrhizal seedlings increased significantly. With the extending of drought stress, the seedlings after re-watering had different recovery ability. Under the re-watering after 14 days drought stress, the SOD, POD and NR activities recovered. The drought resistance of the mycorrhizal seedlings was in the order of Suillus luteus 1 > Suillus luteus 7 > Cantharellus cibarius > Cenococcum geophilum > Pisolithus tinctorius. The SOD and MDA activities had a greater correlation with the mycorrhizal seedlings drought resistance, being able to be used as the indicators to evaluate the drought resistance of mycorrhizal seedlings.

  14. Role of the arbuscular mycorrhizal symbiosis in tolerance response against Armillaria mellea in lavender

    Directory of Open Access Journals (Sweden)

    Cinta Calvet

    2015-09-01

    Full Text Available Lavender species form the arbuscular mycorrhizal symbiosis and are at the same time highly susceptible to white root rot. In an attempt to evaluate the response of mycorrhizal Lavandula angustifolia L. to Armillaria mellea (Vahl:Fr P. Kumm in a greenhouse experiment, plants were previously inoculated with an isolate of the arbuscular mycorrhizal fungus Rhizophagus irregularis (former Glomus intraradices BEG 72 and the influence of the pH growing medium on the plant-symbiont-pathogen interaction was tested in gnotobiotic autotrophic growth systems in which mycorrhizal inoculum was obtained from root organ cultures. After ten months growth dual-inoculated lavender plants grown in containers with a pasteurized substrate mixture produced a similar number of spikes than healthy plants and achieved equivalent plant diameter coverage. When the growing medium in the autotrophic systems was supplemented with calcium carbonate, the inoculation of lavender plantlets with R. irregularis at higher pH (7.0 and 8.5 media caused a significant decrease of A. mellea presence in plant roots, as detected by qPCR. Moreover, the observation of internal root mycorrhizal infection showed that the extent of mycorrhizal colonization increasedin plant rootsgrown at higher pH, indicating that tolerance to white root rot in lavender plants inoculated with R. irregularis could be associated to mycorrhizal establishment.

  15. Enrichment of arbuscular mycorrhizal fungi in a contaminated soil after rehabilitation.

    Science.gov (United States)

    Lopes Leal, Patrícia; Varón-López, Maryeimy; Gonçalves de Oliveira Prado, Isabelle; Valentim Dos Santos, Jessé; Fonsêca Sousa Soares, Cláudio Roberto; Siqueira, José Oswaldo; de Souza Moreira, Fatima Maria

    Spore counts, species composition and richness of arbuscular mycorrhizal fungi, and soil glomalin contents were evaluated in a soil contaminated with Zn, Cu, Cd and Pb after rehabilitation by partial replacement of the contaminated soil with non-contaminated soil, and by Eucalyptus camaldulensis planting with and without Brachiaria decumbens sowing. These rehabilitation procedures were compared with soils from contaminated non-rehabilitated area and non-contaminated adjacent soils. Arbuscular mycorrhizal fungi communities attributes were assessed by direct field sampling, trap culture technique, and by glomalin contents estimate. Arbuscular mycorrhizal fungi was markedly favored by rehabilitation, and a total of 15 arbuscular mycorrhizal fungi morphotypes were detected in the studied area. Species from the Glomus and Acaulospora genera were the most common mycorrhizal fungi. Number of spores was increased by as much as 300-fold, and species richness almost doubled in areas rehabilitated by planting Eucalyptus in rows and sowing B. decumbens in inter-rows. Contents of heavy metals in the soil were negatively correlated with both species richness and glomalin contents. Introduction of B. decumbens together with Eucalyptus causes enrichment of arbuscular mycorrhizal fungi species and a more balanced community of arbuscular mycorrhizal fungi spores in contaminated soil. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  16. Nitrogen isotope fractionation during N uptake via arbuscular mycorrhizal and ectomycorrhizal fungi into grey alder.

    Science.gov (United States)

    Schweiger, Peter F

    2016-10-20

    Arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi affect plant nitrogen (N) dynamics. Plant N isotope patterns have been used to characterise the contribution of ECM fungi to plant N uptake. By quantifying and comparing the effects of an AM and an ECM fungus on growth, N uptake and isotopic composition of one host plant grown at different relative N supply levels, the aim of this study was to improve the mechanistic understanding of natural 15 N abundance patterns in mycorrhizal plants and their underlying causes. Grey alders were inoculated with one ECM fungus or one AM fungus or left non-mycorrhizal. Plants were grown under semi-hydroponic conditions and were supplied with three rates of relative N supply ranging from deficient to luxurious. Neither mycorrhizal fungus increased plant growth or N uptake. AM root colonisation had no effect on whole plant δ 15 N and decreased foliar δ 15 N only under N deficiency. The roots of these plants were 15 N-enriched. ECM root colonisation consistently decreased foliar and whole plant δ 15 N. It is concluded, that both mycorrhizal fungi contributed to plant N uptake into the shoot. Nitrogen isotope fractionation during N assimilation and transformations in fungal mycelia is suggested to have resulted in plants receiving 15 N-depleted N via the mycorrhizal uptake pathways. Negative mycorrhizal growth effects are explained by symbiotic resource trade on carbon and N and decreased direct plant N uptake. Copyright © 2016 Elsevier GmbH. All rights reserved.

  17. Interactions of Heterodera glycines, Macrophomina phaseolina, and Mycorrhizal Fungi on Soybean in Kansas.

    Science.gov (United States)

    Winkler, H E; Hetrick, B A; Todd, T C

    1994-12-01

    The impact of naturally occurring arbuscular mycorrhizal fungi on soybean growth and their interaction with Heterodera glycines were evaluated in nematode-infested and uninfested fields in Kansas. Ten soybean cultivars from Maturity Groups III-V with differential susceptibility to H. glycines were treated with the fungicide benomyl to suppress colonization by naturally occurring mycorrhizal fungi and compared with untreated control plots. In H. glycines-infested soil, susceptible cultivars exhibited 39% lower yields, 28% lower colonization by mycorrhizal fungi, and an eightfold increase in colonization by the charcoal rot fungus, Macrophomina phaseolina, compared with resistant cultivars. In the absence of the nematode, susceptible cultivars exhibited 10% lower yields than resistant cultivars, root colonization of resistant vs. susceptible soybean by mycorrhizal fungi varied with sampling date, and there were no differences in colonization by M. phaseolina between resistant and susceptible cultivars. Benomyl application resulted in 19% greater root growth and 9% higher seed yields in H. glycines-infested soil, but did not affect soybean growth and yield in the absence of the nematode. Colonization of soybean roots by mycorrhizal fungi was negatively correlated with H. glycines population densities due to nematode antagonism to the mycorrhizal fungi rather than suppression of nematode populations. Soybean yields were a function of the pathogenic effects of H. glycines and M. phaseolina, and, to a lesser degree, the stimulatory effects of mycorrhizal fungi.

  18. [Effect of five fungicides on growth of Glycyrrhiza uralensis and efficiency of mycorrhizal symbiosis].

    Science.gov (United States)

    Li, Peng-ying; Yang, Guang; Zhou, Xiu-teng; Zhou, Liane-yun; Shao, Ai-juan; Chen, Mei-lan

    2015-12-01

    In order to obtain the fungicides with minimal impact on efficiency of mycorrhizal symbiosis, the effect of five fungicides including polyoxins, jinggangmycins, thiophanate methylate, chlorothalonil and carbendazim on the growth of medicinal plant and efficiency of mycorrhizal symbiosis were studied. Pot cultured Glycyrrhiza uralensis was treated with different fungicides with the concentration that commonly used in the field. 60 d after treated with fungicides, infection rate, infection density, biomass indexes, photosyn- thetic index and the content of active component were measured. Experimental results showed that carbendazim had the strongest inhibition on mycorrhizal symbiosis effect. Carbendazim significantly inhibited the mycorrhizal infection rate, significantly suppressed the actual photosynthetic efficiency of G. uralensis and the most indicators of biomass. Polyoxins showed the lowest inhibiting affection. Polyoxins had no significant effect on mycorrhizal infection rate, the actual photosynthetic efficiency of G. uralensis and the most indicators of biomass. The other three fungicides also had an inhibitory effect on efficiency of mycorrhizal symbiosis, and the inhibition degrees were all between polyoxins's and carbendazim's. The author considered that fungicide's inhibition degree on mycorrhizal effect might be related with the species of fungicides, so the author suggested that the farmer should try to choose bio-fungicides like polyoxins.

  19. Multi-omics approach identifies molecular mechanisms of plant-fungus mycorrhizal interaction

    Directory of Open Access Journals (Sweden)

    Peter E Larsen

    2016-01-01

    Full Text Available In mycorrhizal symbiosis, plant roots form close, mutually beneficial interactions with soil fungi. Before this mycorrhizal interaction can be established however, plant roots must be capable of detecting potential beneficial fungal partners and initiating the gene expression patterns necessary to begin symbiosis. To predict a plant root – mycorrhizal fungi sensor systems, we analyzed in vitro experiments of Populus tremuloides (aspen tree and Laccaria bicolor (mycorrhizal fungi interaction and leveraged over 200 previously published transcriptomic experimental data sets, 159 experimentally validated plant transcription factor binding motifs, and more than 120-thousand experimentally validated protein-protein interactions to generate models of pre-mycorrhizal sensor systems in aspen root. These sensor mechanisms link extracellular signaling molecules with gene regulation through a network comprised of membrane receptors, signal cascade proteins, transcription factors, and transcription factor biding DNA motifs. Modeling predicted four pre-mycorrhizal sensor complexes in aspen that interact with fifteen transcription factors to regulate the expression of 1184 genes in response to extracellular signals synthesized by Laccaria. Predicted extracellular signaling molecules include common signaling molecules such as phenylpropanoids, salicylate, and, jasmonic acid. This multi-omic computational modeling approach for predicting the complex sensory networks yielded specific, testable biological hypotheses for mycorrhizal interaction signaling compounds, sensor complexes, and mechanisms of gene regulation.

  20. Some Root Traits of Barley (Hordeum vulgare L. as Affected by Mycorrhizal Symbiosis under Drought Stress

    Directory of Open Access Journals (Sweden)

    R. Bayani

    2016-05-01

    Full Text Available The effect of drought stress and mycorrhizal symbiosis on the colonization, root and leaf phosphorous content, root and leaf phosphatase activity, root volume and area as well as shoot dry weight of a variety of hulless barley were evaluated using a completely randomized experimental design (CRD with 3 replications. Treatments were three levels of drought stress of 30, 60 and 90% field capacity and two levels of mycorrhizal with and without inoculation. According to the results, the highest value of leaf phosphorous (1.54 mg/g was observed at mycorrhizal symbiosis against severe drought treatment. Root phosphatase activity was highest (297.9 OD min -1 FW-1 at severe drought stress with mycorrhizal symbiosis which in comparison with mild stress in the presence of mycorrhiza showed 16.6 fold increasing. The control and non-mycorrhizal symbiosis treatments had highest root dry weight (0.091 g. The lowest root volume (0.016 cm2 observed at mycorrhizal symbiosis × severe drought treatment. Generally, Inoculation of barley seed with mycorrhiza at severe water stress could transport more phosphorous to shoot, especially leaf via inducing of leaf and root phosphatase activity. Also, in addition to supply of nutrient sources especially phosphorous for plant, mycorrhizal symbiosis could play an important role in withstanding water stress in plant via increasing of root dry weight and area.

  1. Role of the arbuscular mycorrhizal symbiosis in tolerance response against Armillaria mellea in lavender

    Energy Technology Data Exchange (ETDEWEB)

    Calvet, C.; Garcia-Figueres, F.; Lovato, P.; Camprubi, A.

    2015-07-01

    Lavender species form the arbuscular mycorrhizal symbiosis and are at the same time highly susceptible to white root rot. In an attempt to evaluate the response of mycorrhizal Lavandula angustifolia L. to Armillaria mellea (Vahl:Fr) P. Kumm in a greenhouse experiment, plants were previously inoculated with an isolate of the arbuscular mycorrhizal fungus Rhizophagus irregularis (former Glomus intraradices BEG 72) and the influence of the pH growing medium on the plant-symbiont-pathogen interaction was tested in gnotobiotic autotrophic growth systems in which mycorrhizal inoculum was obtained from root organ cultures. After ten months growth dual-inoculated lavender plants grown in containers with a pasteurized substrate mixture produced a similar number of spikes than healthy plants and achieved equivalent plant diameter coverage. When the growing medium in the autotrophic systems was supplemented with calcium carbonate, the inoculation of lavender plantlets with R. irregularis at higher pH (7.0 and 8.5) media caused a significant decrease of A. mellea presence in plant roots, as detected by qPCR. Moreover, the observation of internal root mycorrhizal infection showed that the extent of mycorrhizal colonization increasedin plant rootsgrown at higher pH, indicating that tolerance to white root rot in lavender plants inoculated with R. irregularis could be associated to mycorrhizal establishment. (Author)

  2. Can Arbuscular Mycorrhizal Fungi Reduce the Growth of Agricultural Weeds?

    Science.gov (United States)

    Veiga, Rita S. L.; Jansa, Jan; Frossard, Emmanuel; van der Heijden, Marcel G. A.

    2011-01-01

    Background Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. Methodology/Principal Findings First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between −22 and −35%). In a subsequent experiment, we selected three of the negatively responding weed species – Echinochloa crus-galli, Setaria viridis and Solanum nigrum – and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum). Finally, we tested whether the presence of a crop (maize) enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. Conclusions/Significance Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field conditions. PMID

  3. Arbuscular mycorrhizal fungi make a complex contribution to soil aggregation

    Science.gov (United States)

    McGee, Peter; Daynes, Cathal; Damien, Field

    2013-04-01

    Soil aggregates contain solid and fluid components. Aggregates develop as a consequence of the organic materials, plants and hyphae of arbuscular mycorrhizal (AM) fungi acting on the solid phase. Various correlative studies indicate hyphae of AM fungi enmesh soil particles, but their impact on the pore space is poorly understood. Hyphae may penetrate between particles, remove water from interstitial spaces, and otherwise re-arrange the solid phase. Thus we might predict that AM fungi also change the pore architecture of aggregates. Direct observations of pore architecture of soil, such as by computer-aided tomography (CT), is difficult. The refractive natures of solid and biological material are similar. The plant-available water in various treatments allows us to infer changes in pore architecture. Our experimental studies indicate AM fungi have a complex role in the formation and development of aggregates. Soils formed from compost and coarse subsoil materials were planted with mycorrhizal or non-mycorrhizal seedlings and the resultant soils compared after 6 or 14 months in separate experiments. As well as enmeshing particles, AM fungi were associated with the development of a complex pore space and greater pore volume. Even though AM fungi add organic matter to soil, the modification of pore space is not correlated with organic carbon. In a separate study, we visualised hyphae of AM fungi in a coarse material using CT. In this study, hyphae appeared to grow close to the surfaces of particles with limited ramification across the pore spaces. Hyphae of AM fungi appear to utilise soil moisture for their growth and development of mycelium. The strong correlation between moisture and hyphae has profound implications for soil aggregation, plant utilisation of soil water, and the distribution of water as water availability declines.

  4. The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.; Aerts, A.; Ahren, D.; Brun, A.; Danchin, E. G. J.; Duchaussoy, F.; Gibon, J.; Kohler, A.; Lindquist, E.; Peresa, V.; Salamov, A.; Shapiro, H. J.; Wuyts, J.; Blaudez, D.; Buee, M.; Brokstein, P.; Canback, B.; Cohen, D.; Courty, P. E.; Coutinho, P. M.; Delaruelle, C.; Detter, J. C.; Deveau, A.; DiFazio, S.; Duplessis, S.; Fraissinet-Tachet, L.; Lucic, E.; Frey-Klett, P.; Fourrey, C.; Feussner, I.; Gay, G.; Grimwood, J.; Hoegger, P. J.; Jain, P.; Kilaru, S.; Labbe, J.; Lin, Y. C.; Legue, V.; Le Tacon, F.; Marmeisse, R.; Melayah, D.; Montanini, B.; Muratet, M.; Nehls, U.; Niculita-Hirzel, H.; Secq, M. P. Oudot-Le; Peter, M.; Quesneville, H.; Rajashekar, B.; Reich, M.; Rouhier, N.; Schmutz, J.; Yin, T.; Chalot, M.; Henrissat, B.; Kues, U.; Lucas, S.; Van de Peer, Y.; Podila, G. K.; Polle, A.; Pukkila, P. J.; Richardson, P. M.; Rouze, P.; Sanders, I. R.; Stajich, J. E.; Tunlid, A.; Tuskan, G.; Grigoriev, I. V.

    2007-08-10

    Mycorrhizal symbioses the union of roots and soil fungi are universal in terrestrial ecosystems and may have been fundamental to land colonization by plants 1, 2. Boreal, temperate and montane forests all depend on ectomycorrhizae1. Identification of the primary factors that regulate symbiotic development and metabolic activity will therefore open the door to understanding the role of ectomycorrhizae in plant development and physiology, allowing the full ecological significance of this symbiosis to be explored. Here we report the genome sequence of the ectomycorrhizal basidiomycete Laccaria bicolor (Fig. 1) and highlight gene sets involved in rhizosphere colonization and symbiosis. This 65-megabase genome assembly contains 20,000 predicted protein-encoding genes and a very large number of transposons and repeated sequences. We detected unexpected genomic features, most notably a battery of effector-type small secreted proteins (SSPs) with unknown function, several of which are only expressed in symbiotic tissues. The most highly expressed SSP accumulates in the proliferating hyphae colonizing the host root. The ectomycorrhizae-specific SSPs probably have a decisive role in the establishment of the symbiosis. The unexpected observation that the genome of L. bicolor lacks carbohydrate-active enzymes involved in degradation of plant cell walls, but maintains the ability to degrade non-plant cell wall polysaccharides, reveals the dual saprotrophic and biotrophic lifestyle of the mycorrhizal fungus that enables it to grow within both soil and living plant roots. The predicted gene inventory of the L. bicolor genome, therefore, points to previously unknown mechanisms of symbiosis operating in biotrophic mycorrhizal fungi. The availability of this genome provides an unparalleled opportunity to develop a deeper understanding of the processes by which symbionts interact with plants within their ecosystem to perform vital functions in the carbon and nitrogen cycles that are

  5. 78 FR 62441 - VA Dental Insurance Program-Federalism

    Science.gov (United States)

    2013-10-22

    ...--Federalism AGENCY: Department of Veterans Affairs. ACTION: Direct final rule. SUMMARY: The Department of... that they are submitted in response to ``RIN 2900-AO85-VA Dental Insurance Program-- Federalism... add preemption language in accordance with the discussion above. Executive Order 13132, Federalism...

  6. 78 FR 63143 - VA Dental Insurance Program-Federalism

    Science.gov (United States)

    2013-10-23

    ...--Federalism AGENCY: Department of Veterans Affairs. ACTION: Proposed rule. SUMMARY: The Department of Veterans... that they are submitted in response to ``RIN 2900-AO86-VA Dental Insurance Program-- Federalism... Order 13132, Federalism Section 6(c) of Executive Order 13132 (entitled ``Federalism'') requires an...

  7. VA Library Service--Today's look at Tomorrow's Library.

    Science.gov (United States)

    Veterans Administration, Washington, DC.

    The Conference Poceedings are divided into three broad topics: systems planning, audiovisuals in biomedical communication, and automation and networking. Speakers from within the Veterans Administration (VA), from the National Medical Audiovisual Center, and the Lister Hill National Center for Biomedical Communications, National Library of…

  8. What does Shulkin's firing mean for the VA?

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2018-03-01

    Full Text Available No abstract available. Article truncated at 150 words. David Shulkin MD, Secretary for Veterans Affairs (VA was finally fired by President Donald Trump ending long speculation (1. Trump nominated his personal physician, Ronny Jackson MD, to fill Shulkin’s post. The day after his firing, Shulkin criticized his firing in a NY Times op-ed claiming pro-privatization factions within the Trump administration led to his ouster (2. “They saw me as an obstacle to privatization who had to be removed,” Dr. Shulkin wrote. “That is because I am convinced that privatization is a political issue aimed at rewarding select people and companies with profits, even if it undermines care for veterans.” Former Secretary Shulkin’s tenure at the VA has had several controversies. First, as undersecretary of Veterans Healthcare and later as secretary money appropriated to the VA to obtain private care under the Veterans Access, Choice, and Accountability Acts of 2014 and the VA Choice and Quality Employment Act of …

  9. Gene expression in mycorrhizal orchid protocorms suggests a friendly plant-fungus relationship.

    Science.gov (United States)

    Perotto, Silvia; Rodda, Marco; Benetti, Alex; Sillo, Fabiano; Ercole, Enrico; Rodda, Michele; Girlanda, Mariangela; Murat, Claude; Balestrini, Raffaella

    2014-06-01

    Orchids fully depend on symbiotic interactions with specific soil fungi for seed germination and early development. Germinated seeds give rise to a protocorm, a heterotrophic organ that acquires nutrients, including organic carbon, from the mycorrhizal partner. It has long been debated if this interaction is mutualistic or antagonistic. To investigate the molecular bases of the orchid response to mycorrhizal invasion, we developed a symbiotic in vitro system between Serapias vomeracea, a Mediterranean green meadow orchid, and the rhizoctonia-like fungus Tulasnella calospora. 454 pyrosequencing was used to generate an inventory of plant and fungal genes expressed in mycorrhizal protocorms, and plant genes could be reliably identified with a customized bioinformatic pipeline. A small panel of plant genes was selected and expression was assessed by real-time quantitative PCR in mycorrhizal and non-mycorrhizal protocorm tissues. Among these genes were some markers of mutualistic (e.g. nodulins) as well as antagonistic (e.g. pathogenesis-related and wound/stress-induced) genes. None of the pathogenesis or wound/stress-related genes were significantly up-regulated in mycorrhizal tissues, suggesting that fungal colonization does not trigger strong plant defence responses. In addition, the highest expression fold change in mycorrhizal tissues was found for a nodulin-like gene similar to the plastocyanin domain-containing ENOD55. Another nodulin-like gene significantly more expressed in the symbiotic tissues of mycorrhizal protocorms was similar to a sugar transporter of the SWEET family. Two genes coding for mannose-binding lectins were significantly up-regulated in the presence of the mycorrhizal fungus, but their role in the symbiosis is unclear.

  10. Monitoring CO2 emissions to gain a dynamic view of carbon allocation to arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Slavíková, Renata; Püschel, David; Janoušková, Martina; Hujslová, Martina; Konvalinková, Tereza; Gryndlerová, Hana; Gryndler, Milan; Weiser, Martin; Jansa, Jan

    2017-01-01

    Quantification of carbon (C) fluxes in mycorrhizal plants is one of the important yet little explored tasks of mycorrhizal physiology and ecology. 13 CO 2 pulse-chase labelling experiments are increasingly being used to track the fate of C in these plant-microbial symbioses. Nevertheless, continuous monitoring of both the below- and aboveground CO 2 emissions remains a challenge, although it is necessary to establish the full C budget of mycorrhizal plants. Here, a novel CO 2 collection system is presented which allows assessment of gaseous CO 2 emissions (including isotopic composition of their C) from both belowground and shoot compartments. This system then is used to quantify the allocation of recently fixed C in mycorrhizal versus nonmycorrhizal Medicago truncatula plants with comparable biomass and mineral nutrition. Using this system, we confirmed substantially greater belowground C drain in mycorrhizal versus nonmycorrhizal plants, with the belowground CO 2 emissions showing large variation because of fluctuating environmental conditions in the glasshouse. Based on the assembled 13 C budget, the C allocation to the mycorrhizal fungus was between 2.3% (increased 13 C allocation to mycorrhizal substrate) and 2.9% (reduction of 13 C allocation to mycorrhizal shoots) of the plant gross photosynthetic production. Although the C allocation to shoot respiration (measured during one night only) did not differ between the mycorrhizal and nonmycorrhizal plants under our experimental conditions, it presented a substantial part (∼10%) of the plant C budget, comparable to the amount of CO 2 released belowground. These results advocate quantification of both above- and belowground CO 2 emissions in future studies.

  11. Arbuscular mycorrhizal fungi alter phosphorus relations of broomsedge (Andropogon virginicus L.) plants

    Energy Technology Data Exchange (ETDEWEB)

    Ning, J.C.; Cumming, J.R.

    2001-07-01

    Broomsedge (Andropogon virginicus L.) is a dominant grass revegetating many abandoned coal-mined lands in West Virginia, USA. Residual soils on such sites are often characterized by low pH, low nutrients, and high aluminium. Experiments were conducted to assess the resistance of broomsedge to limited phosphorus (Pi) availability and to investigate the role that arbuscular mycorrhizal (AM) fungi play in aiding plant growth under low Pi conditions. Pregerminated mycorrhizal and non-mycorrhizal seedlings were grown in a sand-culture system with nutrient solutions containing Pi concentrations ranging from 10 to 100 {mu}M for 8 weeks. Non-mycorrhizal plants exhibited severe inhibition of growth under Pi limitation ({lt}60 {mu}M). Colonization by AM fungi greatly enhanced host plant growth at low Pi concentrations, but did not benefit growth when Pi was readily available (100 {mu}M). In comparison to non-mycorrhizal plants, mycorrhizal plants had higher phosphorus use efficiency at low Pi concentrations and maintained nearly constant tissue nutrient concentrations across the gradient of Pi concentrations investigated. Manganese (Mn) and sodium (Na) accumulated in shoots of nonmycorrhizal plants under Pi limitation. Mycorrhizal plants exhibited lower instantaneous Pi uptake rates and significantly lower C-min values compared to non-mycorrhizal plants. These patterns suggest that the symbiotic association between broomsedge roots and AM fungi effectively maintains nutrient homeostasis through changes in physiological properties, including nutrient uptake, allocation and use. The mycorrhizal association is thus a major adaptation that allows broomsedge to become established on infertile mined lands.

  12. Changes of mycorrhizal colonization along moist gradient in a vineyard of Eger (Hungary

    Directory of Open Access Journals (Sweden)

    Donkó Ádám

    2014-11-01

    Full Text Available The role of mycorrhizal fungi has special importance in the case of low soil moisture because the colonization of vine roots by mycorrhiza increases water and nutrient uptake and thus aids the avoidance of biotic and abiotic stresses of grape. Our aim was to investigate in the Eger wine region the changes of mycorrhizal colonization, water potential, and yield quality and quantity of grape roots at three altitudes, along a changing soil moist gradient. Our results show that the degree of mycorrhizal colonization is higher in drier areas, which supports the water and nutrient uptake of the host plant.

  13. Phosphorus supply, arbuscular mycorrhizal fungal species, and plant genotype impact on the protective efficacy of mycorrhizal inoculation against wheat powdery mildew.

    Science.gov (United States)

    Mustafa, G; Randoux, B; Tisserant, B; Fontaine, J; Magnin-Robert, M; Lounès-Hadj Sahraoui, A; Reignault, Ph

    2016-10-01

    A potential alternative strategy to chemical control of plant diseases could be the stimulation of plant defense by arbuscular mycorrhizal fungi (AMF). In the present study, the influence of three parameters (phosphorus supply, mycorrhizal inoculation, and wheat cultivar) on AMF protective efficiency against Blumeria graminis f. sp. tritici, responsible for powdery mildew, was investigated under controlled conditions. A 5-fold reduction (P/5) in the level of phosphorus supply commonly recommended for wheat in France improved Funneliformis mosseae colonization and promoted protection against B. graminis f. sp. tritici in a more susceptible wheat cultivar. However, a further decrease in P affected plant growth, even under mycorrhizal conditions. Two commercially available AMF inocula (F. mosseae, Solrize®) and one laboratory inoculum (Rhizophagus irregularis) were tested for mycorrhizal development and protection against B. graminis f. sp. tritici of two moderately susceptible and resistant wheat cultivars at P/5. Mycorrhizal levels were the highest with F. mosseae (38 %), followed by R. irregularis (19 %) and Solrize® (SZE, 8 %). On the other hand, the highest protection level against B. graminis f. sp. tritici was obtained with F. mosseae (74 %), followed by SZE (58 %) and R. irregularis (34 %), suggesting that inoculum type rather than mycorrhizal levels determines the protection level of wheat against B. graminis f. sp. tritici. The mycorrhizal protective effect was associated with a reduction in the number of conidia with haustorium and with an accumulation of polyphenolic compounds at B. graminis f. sp. tritici infection sites. Both the moderately susceptible and the most resistant wheat cultivar were protected against B. graminis f. sp. tritici infection by F. mosseae inoculation at P/5, although the underlying mechanisms appear rather different between the two cultivars. This study emphasizes the importance of taking into account the considered

  14. A Mycorrhizal-Specific Ammonium Transporter from Lotus japonicus Acquires Nitrogen Released by Arbuscular Mycorrhizal Fungi1

    Science.gov (United States)

    Guether, Mike; Neuhäuser, Benjamin; Balestrini, Raffaella; Dynowski, Marek; Ludewig, Uwe; Bonfante, Paola

    2009-01-01

    In mycorrhizal associations, the fungal partner assists its plant host by providing nitrogen (N) in addition to phosphate. Arbuscular mycorrhizal (AM) fungi have access to inorganic or organic forms of N and translocate them via arginine from the extra- to the intraradical mycelium, where the N is transferred to the plant without any carbon skeleton. However, the molecular form in which N is transferred, as well as the involved mechanisms, is still under debate. NH4+ seems to be the preferential transferred molecule, but no plant ammonium transporter (AMT) has been identified so far. Here, we offer evidence of a plant AMT that is involved in N uptake during mycorrhiza symbiosis. The gene LjAMT2;2, which has been shown to be the highest up-regulated gene in a transcriptomic analysis of Lotus japonicus roots upon colonization with Gigaspora margarita, has been characterized as a high-affinity AMT belonging to the AMT2 subfamily. It is exclusively expressed in the mycorrhizal roots, but not in the nodules, and transcripts have preferentially been located in the arbusculated cells. Yeast (Saccharomyces cerevisiae) mutant complementation has confirmed its functionality and revealed its dependency on acidic pH. The transport experiments using Xenopus laevis oocytes indicated that, unlike other plant AMTs, LjAMT2;2 transports NH3 instead of NH4+. Our results suggest that the transporter binds charged ammonium in the apoplastic interfacial compartment and releases the uncharged NH3 into the plant cytoplasm. The implications of such a finding are discussed in the context of AM functioning and plant phosphorus uptake. PMID:19329566

  15. 76 FR 79067 - Payment or Reimbursement for Emergency Treatment Furnished by Non-VA Providers in Non-VA...

    Science.gov (United States)

    2011-12-21

    ... DEPARTMENT OF VETERANS AFFAIRS 38 CFR Part 17 RIN 2900-AN49 Payment or Reimbursement for Emergency..., authorize the Secretary of Veterans Affairs to reimburse eligible veterans for costs related to non-VA.... Specifically, section 1725 authorizes reimbursement for emergency treatment for eligible veterans with...

  16. 75 FR 33216 - Payment or Reimbursement for Emergency Treatment Furnished by Non-VA Providers in Non-VA...

    Science.gov (United States)

    2010-06-11

    ... health care services for veterans).'' Proposed Sec. 17.121(a) would establish the clinical decision maker... practice to utilize the services of health care professionals, such as nurses, for purposes of clinical review. For this reason, establishing the clinical decision maker as a ``designated VA clinician'' would...

  17. 78 FR 77204 - Proposed Information Collection (VA National Veterans Sports Programs and Special Event Surveys...

    Science.gov (United States)

    2013-12-20

    ... AGENCY: Office of Public & Intergovernmental Affairs, Department of Veterans Affairs. ACTION: Notice. SUMMARY: The Office of Public Affairs (OPA), Department of Veterans Affairs (VA), is announcing an... DEPARTMENT OF VETERANS AFFAIRS [OMB Control No. 2900-NEW] Proposed Information Collection (VA...

  18. Mycorrhizal synthesis between Lactarius deliciosus and Arbutus unedo L.

    Science.gov (United States)

    Gomes, Filomena; Suárez, Diego; Santos, Rita; Silva, Márcia; Gaspar, Daniel; Machado, Helena

    2016-04-01

    Arbutoid mycorrhizae were synthesized in vitro between Arbutus unedo L. and two isolates of Lactarius deliciosus. The fungal isolates were obtained from sporocarps collected under Pinus sylvestris and in a mixed forest stand of Quercus suber and Pinus pinea. Synthesis tubes filled with a mixture of sterilized peat, vermiculite, and perlite imbibed with nutrient solution were used. Two inoculation methods using solid and liquid media were tested. Shoots from an adult selected clone of A. unedo were used after in vitro rooting by auxin dipping. After 3 months of shoots transfer to the substrate, the root systems were examined for arbutoid mycorrhizae formation and later on ex vitro conditions, 9 months after acclimatization. The inoculum treatment with liquid medium improved the mycorrhizal development for both isolates, in vitro. Sterilized substrate for plant acclimatization increased the mycorrhizal development. The arbutoid mycorrhizae were observed in vitro as well as 9 months after acclimatization. Standard arbutoid mycorrhiza features were observed: pale yellow mantle, typical cruciform appearance, Hartig net (HN), and intracellular hyphal complexes, both confined to the epidermis. L. deliciosus mycorrhizae synthetized in vitro persisted 9 months after plant acclimatization. Morphological observations were confirmed by molecular techniques.

  19. Metal accumulation and detoxification mechanisms in mycorrhizal Betula pubescens.

    Science.gov (United States)

    Fernández-Fuego, D; Bertrand, A; González, A

    2017-12-01

    Metal detoxification in plants is a complex process that involves different mechanisms, such as the retention of metals to the cell wall and their chelation and subsequent compartmentalization in plant vacuoles. In order to identify the mechanisms involved in metal accumulation and tolerance in Betula pubescens, as well as the role of mycorrhization in these processes, mycorrhizal and non-mycorrhizal plants were grown in two industrial soils with contrasting concentrations of heavy metals. Mycorrhization increased metal uptake at low metal concentrations in the soil and reduced it at high metal concentrations, which led to an enhanced growth and biomass production of the host when growing in the most polluted soil. Our results suggest that the sequestration on the cell wall is the main detoxification mechanism in white birch exposed to acute chronic metal-stress, while phytochelatins play a role mitigating metal toxicity inside the cells. Given its high Mn and Zn root-to-shoot translocation rate, Betula pubescens is a very promising species for the phytoremediation of soils polluted with these metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2017-11-01

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

  1. Phylogenetic constrains on mycorrhizal specificity in eight Dendrobium (Orchidaceae) species.

    Science.gov (United States)

    Xing, Xiaoke; Ma, Xueting; Men, Jinxin; Chen, Yanhong; Guo, Shunxing

    2017-05-01

    Plant phylogeny constrains orchid mycorrhizal (OrM) fungal community composition in some orchids. Here, we investigated the structures of the OrM fungal communities of eight Dendrobium species in one niche to determine whether similarities in the OrM fungal communities correlated with the phylogeny of the host plants and whether the Dendrobium-OrM fungal interactions are phylogenetically conserved. A phylogeny based on DNA data was constructed for the eight coexisting Dendrobium species, and the OrM fungal communities were characterized by their roots. There were 31 different fungal lineages associated with the eight Dendrobium species. In total, 82.98% of the identified associations belonging to Tulasnellaceae, and a smaller proportion involved members of the unknown Basidiomycota (9.67%). Community analyses revealed that phylogenetically related Dendrobium tended to interact with a similar set of Tulasnellaceae fungi. The interactions between Dendrobium and Tulasnellaceae fungi were significantly influenced by the phylogenetic relationships among the Dendrobium species. Our results provide evidence that the mycorrhizal specificity in the eight coexisting Dendrobium species was phylogenetically conserved.

  2. DELLA proteins regulate arbuscule formation in arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Floss, Daniela S; Levy, Julien G; Lévesque-Tremblay, Véronique; Pumplin, Nathan; Harrison, Maria J

    2013-12-17

    Most flowering plants are able to form endosymbioses with arbuscular mycorrhizal fungi. In this mutualistic association, the fungus colonizes the root cortex and establishes elaborately branched hyphae, called arbuscules, within the cortical cells. Arbuscule development requires the cellular reorganization of both symbionts, and the resulting symbiotic interface functions in nutrient exchange. A plant symbiosis signaling pathway controls the development of the symbiosis. Several components of the pathway have been identified, but transcriptional regulators that control downstream pathways for arbuscule formation are still unknown. Here we show that DELLA proteins, which are repressors of gibberellic acid (GA) signaling and function at the nexus of several signaling pathways, are required for arbuscule formation. Arbuscule formation is severely impaired in a Medicago truncatula Mtdella1/Mtdella2 double mutant; GA treatment of wild-type roots phenocopies the della double mutant, and a dominant DELLA protein (della1-Δ18) enables arbuscule formation in the presence of GA. Ectopic expression of della1-Δ18 suggests that DELLA activity in the vascular tissue and endodermis is sufficient to enable arbuscule formation in the inner cortical cells. In addition, expression of della1-Δ18 restores arbuscule formation in the symbiosis signaling pathway mutant cyclops/ipd3, indicating an intersection between DELLA and symbiosis signaling for arbuscule formation. GA signaling also influences arbuscule formation in monocots, and a Green Revolution wheat variety carrying dominant DELLA alleles shows enhanced colonization but a limited growth response to arbuscular mycorrhizal symbiosis.

  3. 48 CFR 852.219-71 - VA mentor-protégé program.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false VA mentor-protégÃ....219-71 VA mentor-protégé program. As prescribed in 819.7115(a), insert the following clause: VA Mentor-Protégé Program (DEC 2009) (a) Large businesses are encouraged to participate in the VA Mentor-Protégé...

  4. Arbuscular mycorrhizal colonization, plant chemistry, and aboveground herbivory on Senecio jacobaea

    NARCIS (Netherlands)

    Reidinger, S.; Eschen, R.; Gange, A.C.; Finch, P.; Bezemer, T.M.

    2012-01-01

    Arbuscular mycorrhizal fungi (AMF) can affect insect herbivores by changing plant growth and chemistry. However, many factors can influence the symbiotic relationship between plant and fungus, potentially obscuring experimental treatments and ecosystem impacts. In a field experiment, we assessed AMF

  5. Mycorrhizal fungi associated with Taiwanese Pyrola morrisonensis (Ericaceae in a naturally regenerated forest

    Directory of Open Access Journals (Sweden)

    Yosuke MATSUDA

    2017-11-01

    Full Text Available Pyrola morrisonensis, an evergreen herb in the family Ericaceae, is endemic to Taiwan. We examined mycorrhizal development and the associated fungi in this species. Nine plants were collected in a naturally regenerated forest in central Taiwan. The plants were genetically identical in their internal transcribed spacer (ITS region, and their sequences matched the known sequence for P. morrisonensis. Fine roots of each plant were colonized by mycorrhizal fungi that formed mycorrhizas either with or without fungal mantles. DNA sequences of the ITS region of these fungi suggested that they belonged to mycorrhizal taxa that are common tree symbionts. Among them, members of Thelephoraceae were the dominant taxon in the host plants. These results indicate that P. morrisonensis is intimately associated with mycorrhizal fungi that might also connect with neighboring trees.

  6. Global assessment of arbuscular mycorrhizal fungus diversity reveals very low endemism

    Czech Academy of Sciences Publication Activity Database

    Davison, J.; Moora, M.; Öpik, M.; Adholeya, A.; Ainsaar, L.; Bâ, A.; Burla, S.; Diedhiou, A. G.; Hiiesalu, Inga; Jairus, T.; Johnson, N. C.; Kane, A.; Koorem, K.; Kochar, M.; Ndiaye, C.; Pärtel, M.; Reier, Ü.; Saks, Ü.; Singh, R.; Vasar, M.; Zobel, M.

    2015-01-01

    Roč. 349, č. 6251 (2015), 970-973 ISSN 0036-8075 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * 454 sequencing * diversity Subject RIV: EH - Ecology, Behaviour Impact factor: 34.661, year: 2015

  7. Duration and intensity of shade differentially affects mycorrhizal growth- and phosphorus uptake responses of Medicago truncatula

    Czech Academy of Sciences Publication Activity Database

    Konvalinková, T.; Püschel, David; Janoušková, Martina; Gryndler, M.; Jansa, J.

    2015-01-01

    Roč. 6, FEB 13 (2015), s. 1-11 ISSN 1664-462X Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal symbiosis * light intensity * shading duration Subject RIV: EE - Microbiology, Virology Impact factor: 4.495, year: 2015

  8. Arbuscular mycorrhizal fungi counteract the Janzen-Connell effect of soil pathogens

    NARCIS (Netherlands)

    Liang, Minxia; Liu, Xubing; Etienne, Rampal S; Huang, Fengmin; Wang, Yongfan; Yu, Shixiao

    Soilborne pathogens can contribute to diversity maintenance in tree communities through the Janzen-Connell effect, whereby the pathogenic reduction of seedling performance attenuates with distance from conspecifics. By contrast, arbuscular mycorrhizal fungi (AMF) have been reported to promote

  9. A phenotypic plasticity framework for assessing intraspecific variation in arbuscular mycorrhizal fungal traits

    NARCIS (Netherlands)

    Behm, J.E.; Kiers, E.T.

    2014-01-01

    Statistical models of ecosystem functioning based on species traits are valuable tools for predicting how nutrient cycling will respond to global change. However, species such as arbuscular mycorrhizal fungi (AMF) have evolved high intraspecific trait variation, making trait characterization and

  10. Effects of Microbiotic Soil Crust Organisms and Mycorrhizal Fungi on Seedling Growth of Blackbrush (Coleogyne ramosissima)

    National Research Council Canada - National Science Library

    Pendleton, Rosemary

    1999-01-01

    .... A series of experiments conducted from 1993 to 1997 tested the effect of inoculation with arbuscular mycorrhizal fungi on the growth of young blackbrush seedlings under a variety of soil nutrient conditions...

  11. Reduction of bacterial growth by a vesicular-arbuscular mycorrhizal fungus in the rhizosphere of cucumber (Cucumis sativus L.)

    DEFF Research Database (Denmark)

    Christensen, H.; Jakobsen, I.

    1993-01-01

    Cucumber was grown in a partially sterilized sand-soil mixture with the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus fasciculatum or left uninoculated. Fresh soil extract was places in polyvinyl chloride tubes without propagules of mycorrhizal fungi. Root tips and root segments...... and top of tubes, and of cocci with a diameter of 0.55-0.78 mum in the bulk soil in the center of tubes, were significantly reduced by VAM fungi. The extremely high bacterial biomass (1-7 mg C g-1 dry weight soil) was significant reduced by mycorrhizal colonization on root segments and in bulk soil...... biomass, and changed the spatial pattern of bacterial growth compared to non-mycorrhizal cucumbers. The [H-3]-thymidine incorporation was significantly higher on root tips in the top of tubes, and on root segments and bulk soil in the center of tubes on non-mycorrhizal plants compared to mycorrhizal...

  12. Influence of silver and titanium nanoparticles on arbuscular mycorrhizal colonization and accumulation of radiocaesium in Helianthus annuus

    International Nuclear Information System (INIS)

    Dubchak, S.; Ogar, A.; Mietelski, J. W.; Turnau, K.

    2010-01-01

    The influence of arbuscular mycorrhizal fungus on 1 34Cs uptake by Helianthus annuus was studied in a pilot study under growth chamber conditions. Mycorrhizal plants took up five times more 1 34Cs (up to 250,000 Bq kg - 1 dry weight) than non mycorrhizal plants. Silver and titanium nanoparticles, supplied into the surface soil layer decreased both the mycorrhizal colonization and Cs uptake by mycorrhizal plants. The application of activated carbon attenuated the effect of nanoparticles and increased 1 34Cs uptake in the presence of mycorrhizal fungi (up to 400,000 Bq kg - 1 dry weight). The results underline the possible application of phyto remediation techniques based on mycorrhizas assisted plants in decontamination of both radionuclides and nanoparticles. (Author) 27 refs.

  13. Influence of silver and titanium nanoparticles on arbuscular mycorrhizal colonization and accumulation of radiocaesium in Helianthus annuus

    Energy Technology Data Exchange (ETDEWEB)

    Dubchak, S.; Ogar, A.; Mietelski, J. W.; Turnau, K.

    2010-07-01

    The influence of albacore's mycorrhizal fungus on {sup 1}34Cs uptake by Helianthus annuus was studied in a pilot study under growth chamber conditions. Mycorrhizal plants took up five times more {sup 1}34Cs (up to 250,000 Bq kg{sup -}1 dry weight) than non mycorrhizal plants. Silver and titanium nanoparticles, supplied into the surface soil layer decreased both the mycorrhizal colonization and Cs uptake by mycorrhizal plants. The application of activated carbon attenuated the effect of nanoparticles and increased {sup 1}34Cs uptake in the presence of mycorrhizal fungi (up to 400,000 Bq kg{sup -}1 dry weight). The results underline the possible application of phyto remediation techniques based on mycorrhizas assisted plants in decontamination of both radionuclides and nanoparticles. (Author) 27 refs.

  14. 38 CFR 26.7 - VA environmental decision making and documents.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false VA environmental decision making and documents. 26.7 Section 26.7 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED) ENVIRONMENTAL EFFECTS OF THE DEPARTMENT OF VETERANS AFFAIRS (VA) ACTIONS § 26.7 VA environmental decision making and document...

  15. 76 FR 24570 - Proposed Information Collection (Application for VA Education Benefits) Activity; Comment Request

    Science.gov (United States)

    2011-05-02

    ... (Application for VA Education Benefits) Activity; Comment Request AGENCY: Veterans Benefits Administration, Department of Veterans Affairs. ACTION: Notice. SUMMARY: The Veterans Benefits Administration (VBA... Under the Montgomery GI Bill, VA Form 22-1990E. c. Application for VA Education Benefits Under the...

  16. 78 FR 18425 - Proposed Information Collection VA Police Officer Pre-Employment Screening Checklist); Comment...

    Science.gov (United States)

    2013-03-26

    ... techniques or the use of other forms of information technology. Title: VA Police Officer Pre-Employment... Police Officer Pre-Employment Screening Checklist); Comment Request AGENCY: Office of Operations... approved collection. Abstract: VA personnel complete VA Form 0120 to document pre- employment history and...

  17. 48 CFR 852.219-9 - VA Small business subcontracting plan minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false VA Small business... Provisions and Clauses 852.219-9 VA Small business subcontracting plan minimum requirements. As prescribed in subpart 819.709, insert the following clause: VA Small Business Subcontracting Plan Minimum Requirements...

  18. 76 FR 71920 - Payment for Home Health Services and Hospice Care by Non-VA Providers

    Science.gov (United States)

    2011-11-21

    ... concerning the billing methodology for non-VA providers of home health services and hospice care. The proposed rulemaking would include home health services and hospice care under the VA regulation governing... to ``RIN 2900-AN98--Payment for home health and services and hospice care by non-VA providers...

  19. 78 FR 56271 - FY 2014-2020 Draft VA Strategic Plan

    Science.gov (United States)

    2013-09-12

    ... DEPARTMENT OF VETERANS AFFAIRS FY 2014-2020 Draft VA Strategic Plan AGENCY: Department of Veterans... Affairs (VA) is announcing the availability of the FY 2014-2020 Draft VA Strategic Plan (Strategic Plan... Act of 2010 (GPRAMA) (Pub. L. 111-352). The Strategic Plan provides the Department's long-term...

  20. 78 FR 76412 - Agency Information Collection (VA National Rehabilitation Special Events, Event Registration...

    Science.gov (United States)

    2013-12-17

    ... INFORMATION: Titles: a. National Disabled Veterans Winter Sports Clinic Application, VA Form 0924a, c, d and..., c, e. j. Voluntary Service Application, VA Form 0927f. k. National Veterans Summer sports Clinic... Festival Event Application, VA0929a, b, c, d, e, f, g, h. Type of Review: Revision of an already approved...

  1. VaR: Exchange Rate Risk and Jump Risk

    Directory of Open Access Journals (Sweden)

    Fen-Ying Chen

    2010-01-01

    Full Text Available Incorporating the Poisson jumps and exchange rate risk, this paper provides an analytical VaR to manage market risk of international portfolios over the subprime mortgage crisis. There are some properties in the model. First, different from past studies in portfolios valued only in one currency, this model considers portfolios not only with jumps but also with exchange rate risk, that is vital for investors in highly integrated global financial markets. Second, in general, the analytical VaR solution is more accurate than historical simulations in terms of backtesting and Christoffersen's independence test (1998 for small portfolios and large portfolios. In other words, the proposed model is reliable not only for a portfolio on specific stocks but also for a large portfolio. Third, the model can be regarded as the extension of that of Kupiec (1999 and Chen and Liao (2009.

  2. Mycorrhizal fungi influence on silver uptake and membrane protein gene expression following silver nanoparticle exposure

    Energy Technology Data Exchange (ETDEWEB)

    Noori, Azam [State University of New York, College of Environmental Science and Forestry (United States); White, Jason C. [Connecticut Agricultural Experiment Station (United States); Newman, Lee A., E-mail: lanewman@esf.edu [State University of New York, College of Environmental Science and Forestry (United States)

    2017-02-15

    The rapid growth of nanotechnology and the high demand for nanomaterial use have greatly increased the risk of particle release into the environment. Understanding nanomaterial interactions with crop species and their associated microorganisms is critical to food safety and security. In the current study, tomato was inoculated with mycorrhizal fungi and subsequently exposed to 12, 24, or 36 mg/kg of 2- or 15-nm silver nanoparticles (Ag-NPs). Mycorrhizal (M) and non-mycorrhizal (NM) tomatoes exposed to 36 mg/kg of 2-nm Ag-NPs accumulated 1300 and 1600 μg/g silver in their tissues, respectively. Mycorrhizal plants accumulated 14% less silver compared to non-mycorrhizal plants. To begin to understand the mechanisms by which plants accumulate NPs, the expression of two aquaporin channel genes, the plasma membrane intrinsic protein (PIP) and the tonoplast membrane intrinsic protein (TIP), and one potassium channel (KC) gene were studied. In non-mycorrhizal plants, the expression of KC, PIP, and TIP was eight, five, and nine times higher than the control, respectively. These expressions for mycorrhizal plants were 5.8, 3.5, and 2 times higher than controls, respectively. The expression of KC and PIP, which are located on the plasma membrane, was 3.5 and 2.5, respectively, times higher than TIP, which is located on the tonoplast. PIP expression was significantly higher in NM tomatoes exposed to 12 mg/kg of 2-nm Ag-NPs compared to M plants. These results show that mycorrhizal colonization decreases Ag accumulation in NP-exposed plants and also moderates changes in expression level of membrane transport proteins.

  3. Mycorrhizal fungi influence on silver uptake and membrane protein gene expression following silver nanoparticle exposure

    International Nuclear Information System (INIS)

    Noori, Azam; White, Jason C.; Newman, Lee A.

    2017-01-01

    The rapid growth of nanotechnology and the high demand for nanomaterial use have greatly increased the risk of particle release into the environment. Understanding nanomaterial interactions with crop species and their associated microorganisms is critical to food safety and security. In the current study, tomato was inoculated with mycorrhizal fungi and subsequently exposed to 12, 24, or 36 mg/kg of 2- or 15-nm silver nanoparticles (Ag-NPs). Mycorrhizal (M) and non-mycorrhizal (NM) tomatoes exposed to 36 mg/kg of 2-nm Ag-NPs accumulated 1300 and 1600 μg/g silver in their tissues, respectively. Mycorrhizal plants accumulated 14% less silver compared to non-mycorrhizal plants. To begin to understand the mechanisms by which plants accumulate NPs, the expression of two aquaporin channel genes, the plasma membrane intrinsic protein (PIP) and the tonoplast membrane intrinsic protein (TIP), and one potassium channel (KC) gene were studied. In non-mycorrhizal plants, the expression of KC, PIP, and TIP was eight, five, and nine times higher than the control, respectively. These expressions for mycorrhizal plants were 5.8, 3.5, and 2 times higher than controls, respectively. The expression of KC and PIP, which are located on the plasma membrane, was 3.5 and 2.5, respectively, times higher than TIP, which is located on the tonoplast. PIP expression was significantly higher in NM tomatoes exposed to 12 mg/kg of 2-nm Ag-NPs compared to M plants. These results show that mycorrhizal colonization decreases Ag accumulation in NP-exposed plants and also moderates changes in expression level of membrane transport proteins.

  4. Does responsiveness to arbuscular mycorrhizal fungi depend on plant invasive status?

    Science.gov (United States)

    Reinhart, Kurt O; Lekberg, Ylva; Klironomos, John; Maherali, Hafiz

    2017-08-01

    Differences in the direction and degree to which invasive alien and native plants are influenced by mycorrhizal associations could indicate a general mechanism of plant invasion, but whether or not such differences exist is unclear. Here, we tested whether mycorrhizal responsiveness varies by plant invasive status while controlling for phylogenetic relatedness among plants with two large grassland datasets. Mycorrhizal responsiveness was measured for 68 taxa from the Northern Plains, and data for 95 taxa from the Central Plains were included. Nineteen percent of taxa from the Northern Plains had greater total biomass with mycorrhizas while 61% of taxa from the Central Plains responded positively. For the Northern Plains taxa, measurable effects often depended on the response variable (i.e., total biomass, shoot biomass, and root mass ratio) suggesting varied resource allocation strategies when roots are colonized by arbuscular mycorrhizal fungi. In both datasets, invasive status was nonrandomly distributed on the phylogeny. Invasive taxa were mainly from two clades, that is, Poaceae and Asteraceae families. In contrast, mycorrhizal responsiveness was randomly distributed over the phylogeny for taxa from the Northern Plains, but nonrandomly distributed for taxa from the Central Plains. After controlling for phylogenetic similarity, we found no evidence that invasive taxa responded differently to mycorrhizas than other taxa. Although it is possible that mycorrhizal responsiveness contributes to invasiveness in particular species, we find no evidence that invasiveness in general is associated with the degree of mycorrhizal responsiveness. However, mycorrhizal responsiveness among species grown under common conditions was highly variable, and more work is needed to determine the causes of this variation.

  5. Resistance to high level of Cu (Copper) by arbuscular mycorrhizal, saprobe Fungi and Eucalyptus globules

    Energy Technology Data Exchange (ETDEWEB)

    Arriagada, C.; Pereira, G.; Machuca, A.; Alvear, M.; Martin, J.; Ocampo, J.

    2009-07-01

    The effects of saprobe and arbuscular mycorrhizal (AM) fungi on growth, chorophyll, root length colonization and succinate dehydrogenase (SDH) activity was measured in Eucalyptus globulus Labill., plants growing in soil with high level of Cu were investigated. The application of Cu inhibited the development of mycelia of the saprobe fungi Fusarium concolor and Trichoderma koningii and the hyphal length of the arbuscular mycorrhizal fungi (AM) Glomus mosseaae and G. deserticola in vitro. (Author)

  6. Resistance to high level of Cu (Copper) by arbuscular mycorrhizal, saprobe Fungi and Eucalyptus globules

    International Nuclear Information System (INIS)

    Arriagada, C.; Pereira, G.; Machuca, A.; Alvear, M.; Martin, J.; Ocampo, J.

    2009-01-01

    The effects of saprobe and arbuscular mycorrhizal (AM) fungi on growth, chorophyll, root length colonization and succinate dehydrogenase (SDH) activity was measured in Eucalyptus globulus Labill., plants growing in soil with high level of Cu were investigated. The application of Cu inhibited the development of mycelia of the saprobe fungi Fusarium concolor and Trichoderma koningii and the hyphal length of the arbuscular mycorrhizal fungi (AM) Glomus mosseae and G. deserticola in vitro. (Author)

  7. Differences in mycorrhizal communities between Epipactis palustris, E. helleborine and its presumed sister species E. neerlandica.

    Science.gov (United States)

    Jacquemyn, Hans; Waud, Michael; Lievens, Bart; Brys, Rein

    2016-07-01

    In orchid species that have populations occurring in strongly contrasting habitats, mycorrhizal divergence and other habitat-specific adaptations may lead to the formation of reproductively isolated taxa and ultimately to species formation. However, little is known about the mycorrhizal communities associated with recently diverged sister taxa that occupy different habitats. In this study, 454 amplicon pyrosequencing was used to investigate mycorrhizal communities associating with Epipactis helleborine in its typical forest habitat and with its presumed sister species E. neerlandica that almost exclusively occurs in coastal dune habitats. Samples of the phylogenetically more distant E. palustris, which co-occurred with E. neerlandica, were also included to investigate the role of habitat-specific conditions on mycorrhizal communities. A total of 105 operational taxonomic units (OTUs) of putative orchid mycorrhizal fungi were observed in the three studied species. The majority of these fungi were endophytic fungi of Helotiales and ectomycorrhizal fungi belonging to Thelephoraceae, Sebacinaceae and Inocybaceae. In addition, a large number of other ectomycorrhizal taxa were detected, including Cortinarius, Cenococcum, Tuber, Geopora, Wilcoxina, Meliniomyces, Hebeloma, Tricholoma, Russula and Peziza Mycorrhizal communities differed significantly between the three species, but differences were most pronounced between the forest species (E. helleborine) and the two dune slack species (E. neerlandica and E. palustris). The results clearly showed that recently diverged orchid species that occupy different habitats were characterized by significantly different mycorrhizal communities and call for more detailed experiments that aim at elucidating the contribution of habitat-specific adaptations in general and mycorrhizal divergence in particular to the process of speciation in orchids. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany

  8. DNA pyrosequencing evidence for large diversity differences between natural and managed coffee mycorrhizal fungal communities

    OpenAIRE

    De Beenhouwer , Matthias; Muleta , Diriba; Peeters , Bram; Van Geel , Maarten; Lievens , Bart; Honnay , Olivier

    2015-01-01

    International audience; Arabica coffee is a major agricultural commodity worldwide, representing 60 % of the world’s coffee production. Arabica coffee is cultivated in more than 36 countries and is a key cash crop for many developing countries. Despite the coffee’s huge economic importance, there is very limited knowledge on the association of arbuscular mycorrhizal fungi with coffee roots. Therefore, we assessed the mycorrhizal diversity and community composition in Arabica coffee (Coffea ar...

  9. Identification of a Vesicular-Arbuscular Mycorrhizal Fungus by Using Monoclonal Antibodies in an Enzyme-Linked Immunosorbent Assay †

    OpenAIRE

    Wright, Sara F.; Morton, Joseph B.; Sworobuk, Janis E.

    1987-01-01

    Spore morphology is currently used to identify species of vesicular-arbuscular mycorrhizal fungi. We report the first use of a highly specific immunological method for identification of a vesicular-arbuscular mycorrhizal fungus. Two monoclonal antibodies were produced against Glomus occultum. Monoclonal antibodies reacted strongly with both spores and hyphae in an indirect enzyme-linked immunosorbent assay. All other mycorrhizal (29 species) and nonmycorrhizal (5 species) fungi tested were no...

  10. QCD sum-rules for V-A spectral functions

    International Nuclear Information System (INIS)

    Chakrabarti, J.; Mathur, V.S.

    1980-01-01

    The Borel transformation technique of Shifman et al is used to obtain QCD sum-rules for V-A spectral functions. In contrast to the situation in the original Weinberg sum-rules and those of Bernard et al, the problem of saturating the sum-rules by low lying resonances is brought under control. Furthermore, the present sum-rules, on saturation, directly determine useful phenomenological parameters

  11. CoVaCS: a consensus variant calling system.

    Science.gov (United States)

    Chiara, Matteo; Gioiosa, Silvia; Chillemi, Giovanni; D'Antonio, Mattia; Flati, Tiziano; Picardi, Ernesto; Zambelli, Federico; Horner, David Stephen; Pesole, Graziano; Castrignanò, Tiziana

    2018-02-05

    The advent and ongoing development of next generation sequencing technologies (NGS) has led to a rapid increase in the rate of human genome re-sequencing data, paving the way for personalized genomics and precision medicine. The body of genome resequencing data is progressively increasing underlining the need for accurate and time-effective bioinformatics systems for genotyping - a crucial prerequisite for identification of candidate causal mutations in diagnostic screens. Here we present CoVaCS, a fully automated, highly accurate system with a web based graphical interface for genotyping and variant annotation. Extensive tests on a gold standard benchmark data-set -the NA12878 Illumina platinum genome- confirm that call-sets based on our consensus strategy are completely in line with those attained by similar command line based approaches, and far more accurate than call-sets from any individual tool. Importantly our system exhibits better sensitivity and higher specificity than equivalent commercial software. CoVaCS offers optimized pipelines integrating state of the art tools for variant calling and annotation for whole genome sequencing (WGS), whole-exome sequencing (WES) and target-gene sequencing (TGS) data. The system is currently hosted at Cineca, and offers the speed of a HPC computing facility, a crucial consideration when large numbers of samples must be analysed. Importantly, all the analyses are performed automatically allowing high reproducibility of the results. As such, we believe that CoVaCS can be a valuable tool for the analysis of human genome resequencing studies. CoVaCS is available at: https://bioinformatics.cineca.it/covacs .

  12. Validation of KENO V.a: Comparison with critical experiments

    International Nuclear Information System (INIS)

    Jordan, W.C.; Landers, N.F.; Petrie, L.M.

    1986-12-01

    Section 1 of this report documents the validation of KENO V.a against 258 critical experiments. Experiments considered were primarily high or low enriched uranium systems. The results indicate that the KENO V.a Monte Carlo Criticality Program accurately calculates a broad range of critical experiments. A substantial number of the calculations showed a positive or negative bias in excess of 1 1/2% in k-effective (k/sub eff/). Classes of criticals which show a bias include 3% enriched green blocks, highly enriched uranyl fluoride slab arrays, and highly enriched uranyl nitrate arrays. If these biases are properly taken into account, the KENO V.a code can be used with confidence for the design and criticality safety analysis of uranium-containing systems. Sections 2 of this report documents the results of investigation into the cause of the bias observed in Sect. 1. The results of this study indicate that the bias seen in Sect. 1 is caused by code bias, cross-section bias, reporting bias, and modeling bias. There is evidence that many of the experiments used in this validation and in previous validations are not adequately documented. The uncertainty in the experimental parameters overshadows bias caused by the code and cross sections and prohibits code validation to better than about 1% in k/sub eff/. 48 refs., 19 figs., 19 tabs

  13. Vectorization of the KENO V.a criticality safety code

    International Nuclear Information System (INIS)

    Hollenbach, D.F.; Dodds, H.L.; Petrie, L.M.

    1991-01-01

    The development of the vector processor, which is used in the current generation of supercomputers and is beginning to be used in workstations, provides the potential for dramatic speed-up for codes that are able to process data as vectors. Unfortunately, the stochastic nature of Monte Carlo codes prevents the old scalar version of these codes from taking advantage of the vector processors. New Monte Carlo algorithms that process all the histories undergoing the same event as a batch are required. Recently, new vectorized Monte Carlo codes have been developed that show significant speed-ups when compared to the scalar version of themselves or equivalent codes. This paper discusses the vectorization of an already existing and widely used criticality safety code, KENO V.a All the changes made to KENO V.a are transparent to the user making it possible to upgrade from the standard scalar version of KENO V.a to the vectorized version without learning a new code

  14. Metagenomic Analyses of the Viruses Detected in Mycorrhizal Fungi and Their Host Orchid.

    Science.gov (United States)

    Shimura, Hanako; Masuta, Chikara; Koda, Yasunori

    2018-01-01

    In nature, mycorrhizal association with soilborne fungi is indispensable for orchid families. Fungal structures from compatible endo-mycorrhizal fungi in orchid cells are digested in cells to be supplied to orchids as nutrition. Because orchid seeds lack the reserves for germination, they keep receiving nutrition through mycorrhizal formation from seed germination until shoots develop (leaves) and become photoautotrophic. Seeds of all orchid species surely geminate with the help of their own fungal partners, and this specific partnership has been acquired for a long evolutional history between orchids and fungi.We have studied the interactions between orchids and mycorrhizal fungi and recently conducted transcriptome analyses (RNAseq) by a next-generation sequencing (NGS) approach. It is possible that orchid RNA isolated form naturally grown plants is contaminated with RNAs derived from mycorrhizal fungi in the orchid cells. To avoid such contamination, we here prepared aseptically germinated orchid plants (i.e., fungus-free plants) together with a pure-cultured fungal isolate and field-growing orchid samples. In the cDNA library prepared from orchid and fungal tissues, we found that partitivirus-like sequences were common in an orchid and its mycorrhizal fungus. These partitivirus-like sequences were closely related by a phylogenetic analysis, suggesting that transmission of an ancestor virus between the two organisms occurred through the specific relation of the orchid and its associated fungus.

  15. Arbuscular mycorrhizal colonization in soil fertilized by organic and mineral fertilizers

    Science.gov (United States)

    Dvořáčková, Helena; Záhora, Jaroslav; Mikajlo, Irina; Elbl, Jakub; Kynický, Jindřich; Hladký, Jan; Brtnický, Martin

    2017-04-01

    The level of arbuscular mycorrhizal colonization of roots represents one of the best parameters for assessing soil quality. This special type of symbiosis helps plants to obtain nutrients of the distant area which are unavailable without cooperation with arbuscular mycorrhizal fungi. For example the plant available form of phosphorus is of the most important elements in plant nutrition. This element can't move (significantly) throw the soil and it could be unachievable for root system of plant. The same situation also applies to other important nutrients and water. Colonization of individual roots by arbuscular mycorrhizal fungi has a direct effect on the enlargement of the root system but plant needs to invest sugar substance for development of fungi. It's very difficult to understand when fungi colonization represents indicator of good soil condition. And when it provides us with information "about plant stress". The main goal of our work was to compare the effect of different fertilizers application on development of arbuscular mycorrhizal colonization. We worked with organic fertilizers such as biochar from residual biomass, biochar from sewage sludge and ageing biochar and with mineral fertilizer DAM 390 (mixture of ammonium 25 %, nitrate 25 % and urea nitrogen 50 %). Effect of different types of the above fertilizers on development of arbuscular mycorrhizal colonization was tested by pot experiment with indicator plant Lactuca sativa L. The highest (P arbuscular mycorrhizal colonization of roots.

  16. Effects of arbuscular mycorrhizal fungi on growth and nitrogen uptake of Chrysanthemum morifolium under salt stress.

    Science.gov (United States)

    Wang, Yanhong; Wang, Minqiang; Li, Yan; Wu, Aiping; Huang, Juying

    2018-01-01

    Soil salinity is a common and serious environmental problem worldwide. Arbuscular mycorrhizal fungi (AMF) are considered as bio-ameliorators of soil salinity tolerance in plants. However, few studies have addressed the possible benefits of AMF inoculation for medicinal plants under saline conditions. In this study, we examined the effects of colonization with two AMF, Funneliformis mosseae and Diversispora versiformis, alone and in combination, on the growth and nutrient uptake of the medicinal plant Chrysanthemum morifolium (Hangbaiju) in a greenhouse salt stress experiment. After 6 weeks of a non-saline pretreatment, Hangbaiju plants with and without AMF were grown for five months under salinity levels that were achieved using 0, 50 and 200 mM NaCl. Root length, shoot and root dry weight, total dry weight, and root N concentration were higher in the mycorrhizal plants than in the non-mycorrhizal plants under conditions of moderate salinity, especially with D. versiformis colonization. As salinity increased, mycorrhizal colonization and mycorrhizal dependence decreased. The enhancement of root N uptake is probably the main mechanism underlying salt tolerance in mycorrhizal plants. These results suggest that the symbiotic associations between the fungus D. versiformis and C. morifolium plants may be useful in biotechnological practice.

  17. Linking root traits to nutrient foraging in arbuscular mycorrhizal trees in a temperate forest.

    Science.gov (United States)

    Eissenstat, David M; Kucharski, Joshua M; Zadworny, Marcin; Adams, Thomas S; Koide, Roger T

    2015-10-01

    The identification of plant functional traits that can be linked to ecosystem processes is of wide interest, especially for predicting vegetational responses to climate change. Root diameter of the finest absorptive roots may be one plant trait that has wide significance. Do species with relatively thick absorptive roots forage in nutrient-rich patches differently from species with relatively fine absorptive roots? We measured traits related to nutrient foraging (root morphology and architecture, root proliferation, and mycorrhizal colonization) across six coexisting arbuscular mycorrhizal (AM) temperate tree species with and without nutrient addition. Root traits such as root diameter and specific root length were highly correlated with root branching intensity, with thin-root species having higher branching intensity than thick-root species. In both fertilized and unfertilized soil, species with thin absorptive roots and high branching intensity showed much greater root length and mass proliferation but lower mycorrhizal colonization than species with thick absorptive roots. Across all species, fertilization led to increased root proliferation and reduced mycorrhizal colonization. These results suggest that thin-root species forage more by root proliferation, whereas thick-root species forage more by mycorrhizal fungi. In mineral nutrient-rich patches, AM trees seem to forage more by proliferating roots than by mycorrhizal fungi. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  18. Effect of different arbuscular mycorrhizal fungal isolates on growth and arsenic accumulation in Plantago lanceolata L

    International Nuclear Information System (INIS)

    Orłowska, Elżbieta; Godzik, Barbara; Turnau, Katarzyna

    2012-01-01

    The role of indigenous and non-indigenous arbuscular mycorrhizal fungi (AMF) on As uptake by Plantago lanceolata L. growing on substrate originating from mine waste rich in As was assessed in a pot experiment. P. lanceolata inoculated with AMF had higher shoot and root biomass and lower concentrations of As in roots than the non-inoculated plants. There were significant differences in As concentration and uptake between different AMF isolates. Inoculation with the indigenous isolate resulted in increased transfer of As from roots to shoots; AMF from non-polluted area apparently restricted plants from absorbing As to the tissue; and plants inoculated with an AMF isolate from Zn–Pb waste showed strong As retainment within the roots. Staining with dithizone indicated that AMF might be actively involved in As accumulation. The mycorrhizal colonization affected also the concentration of Cd and Zn in roots and Pb concentration, both in shoots and roots. - Highlights: ► The role of arbuscular mycorrhizal fungi (AMF) in As uptake was studied. ► Growth of Plantago lanceolata was significantly enhanced by mycorrhizal inoculation. ► Arsenic concentration and uptake significantly depended on the AMF isolate. ► Arbuscular mycorrhizal fungi may be useful for bioremediation of As contaminated wastes. - Effect of arbuscular mycorrhizal fungi on As uptake by Plantago lanceolata strongly depends on the origin of fungal isolates.

  19. MycoDB, a global database of plant response to mycorrhizal fungi

    Science.gov (United States)

    Chaudhary, V. Bala; Rúa, Megan A.; Antoninka, Anita; Bever, James D.; Cannon, Jeffery; Craig, Ashley; Duchicela, Jessica; Frame, Alicia; Gardes, Monique; Gehring, Catherine; Ha, Michelle; Hart, Miranda; Hopkins, Jacob; Ji, Baoming; Johnson, Nancy Collins; Kaonongbua, Wittaya; Karst, Justine; Koide, Roger T.; Lamit, Louis J.; Meadow, James; Milligan, Brook G.; Moore, John C.; Pendergast, Thomas H., IV; Piculell, Bridget; Ramsby, Blake; Simard, Suzanne; Shrestha, Shubha; Umbanhowar, James; Viechtbauer, Wolfgang; Walters, Lawrence; Wilson, Gail W. T.; Zee, Peter C.; Hoeksema, Jason D.

    2016-05-01

    Plants form belowground associations with mycorrhizal fungi in one of the most common symbioses on Earth. However, few large-scale generalizations exist for the structure and function of mycorrhizal symbioses, as the nature of this relationship varies from mutualistic to parasitic and is largely context-dependent. We announce the public release of MycoDB, a database of 4,010 studies (from 438 unique publications) to aid in multi-factor meta-analyses elucidating the ecological and evolutionary context in which mycorrhizal fungi alter plant productivity. Over 10 years with nearly 80 collaborators, we compiled data on the response of plant biomass to mycorrhizal fungal inoculation, including meta-analysis metrics and 24 additional explanatory variables that describe the biotic and abiotic context of each study. We also include phylogenetic trees for all plants and fungi in the database. To our knowledge, MycoDB is the largest ecological meta-analysis database. We aim to share these data to highlight significant gaps in mycorrhizal research and encourage synthesis to explore the ecological and evolutionary generalities that govern mycorrhizal functioning in ecosystems.

  20. Effect of arbuscular mycorrhizal fungus (Glomus caledonium) on the accumulation and metabolism of atrazine in maize (Zea mays L.) and atrazine dissipation in soil

    Energy Technology Data Exchange (ETDEWEB)

    Huang Honglin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18th Shuangqinglu, Haidian District, Beijing 100085 (China); Zhang Shuzhen [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18th Shuangqinglu, Haidian District, Beijing 100085 (China)]. E-mail: szzhang@mail.rcees.ac.cn; Shan Xiaoquan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18th Shuangqinglu, Haidian District, Beijing 100085 (China); Chen Baodong [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18th Shuangqinglu, Haidian District, Beijing 100085 (China); Zhu Yongguan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18th Shuangqinglu, Haidian District, Beijing 100085 (China); Bell, J. Nigel B. [Center for Environmental Policy, Imperial College, London (United Kingdom)

    2007-03-15

    Effects of an arbuscular mycorrhizal (AM) fungus (Glomus caledonium) on accumulation and metabolism of atrazine in maize grown in soil contaminated with different concentrations of atrazine were investigated in a series of pot experiments. Roots of mycorrhizal plants accumulated more atrazine than non-mycorrhizal roots. In contrast, atrazine accumulation in shoot decreased in mycorrhizal compared with non-mycorrhizal plants. No atrazine derivatives were detected in the soil, either with or without mycorrhizal colonization. However, atrazine metabolites, deethylatrazine (DEA) and deisopropylatrazine (DIA), were detected in plant roots and the AM colonization enhanced the metabolism. After plant harvest atrazine concentrations decreased markedly in the soils compared to the initial concentrations. The decreases were the most in rhizosphere soil and then near-rhizosphere soil and the least in bulk soil. Mycorrhizal treatment enhanced atrazine dissipation in the near-rhizosphere and bulk soils irrespective of atrazine application rates. - Arbuscular mycorrhizal fungus increases the accumulation and metabolism of atrazine in maize.

  1. Effect of arbuscular mycorrhizal fungus (Glomus caledonium) on the accumulation and metabolism of atrazine in maize (Zea mays L.) and atrazine dissipation in soil

    International Nuclear Information System (INIS)

    Huang Honglin; Zhang Shuzhen; Shan Xiaoquan; Chen Baodong; Zhu Yongguan; Bell, J. Nigel B.

    2007-01-01

    Effects of an arbuscular mycorrhizal (AM) fungus (Glomus caledonium) on accumulation and metabolism of atrazine in maize grown in soil contaminated with different concentrations of atrazine were investigated in a series of pot experiments. Roots of mycorrhizal plants accumulated more atrazine than non-mycorrhizal roots. In contrast, atrazine accumulation in shoot decreased in mycorrhizal compared with non-mycorrhizal plants. No atrazine derivatives were detected in the soil, either with or without mycorrhizal colonization. However, atrazine metabolites, deethylatrazine (DEA) and deisopropylatrazine (DIA), were detected in plant roots and the AM colonization enhanced the metabolism. After plant harvest atrazine concentrations decreased markedly in the soils compared to the initial concentrations. The decreases were the most in rhizosphere soil and then near-rhizosphere soil and the least in bulk soil. Mycorrhizal treatment enhanced atrazine dissipation in the near-rhizosphere and bulk soils irrespective of atrazine application rates. - Arbuscular mycorrhizal fungus increases the accumulation and metabolism of atrazine in maize

  2. Uptake of pulse injected nitrogen by soil microbes and mycorrhizal and non-mycorrhizal plants in a species-diverse subarctic heath ecosystem

    DEFF Research Database (Denmark)

    Andresen, Louise Christoffersen; Jonasson, Sven; Strom, Lena

    2008-01-01

    15N labeled ammonium, glycine or glutamic acid was injected into subarctic heath soil in situ, with the purpose of investigating how the nitrogen added in these pulses was subsequently utilized and cycled in the ecosystem. We analyzed the acquisition of 15N label in mycorrhizal and non-mycorrhiza......15N labeled ammonium, glycine or glutamic acid was injected into subarctic heath soil in situ, with the purpose of investigating how the nitrogen added in these pulses was subsequently utilized and cycled in the ecosystem. We analyzed the acquisition of 15N label in mycorrhizal and non...

  3. Arbuscular mycorrhizal fungi and tolerance of temperature stress in plants

    DEFF Research Database (Denmark)

    Zhu, Xiancan; Song, Fengbin; Liu, Fulai

    2017-01-01

    Temperature is one of the most important environmental factors that determine the growth and productivity of plants across the globe. Many physiological and biochemical processes and functions are affected by low and high temperature stresses. Arbuscular mycorrhizal (AM) symbiosis has been shown...... to improve tolerance to temperature stress in plants. This chapter addresses the effect of AM symbiosis on plant growth and biomass production, water relations (water potential, stomatal conductance, and aquaporins), photosynthesis (photosynthetic rate, chlorophyll, and chlorophyll fluorescence), plasma...... tolerance of the host plants via enhancing water and nutrient uptake, improving photosynthetic capacity and efficiency, protecting plant against oxidative damage, and increasing accumulation of osmolytes are discussed. This chapter also provides some future perspectives for better understanding...

  4. Impact of arbuscular mycorrhizal fungi on uranium accumulation by plants

    International Nuclear Information System (INIS)

    Dupre de Boulois, H.; Joner, E.J.; Leyval, C.; Jakobsen, I.; Chen, B.D.; Roos, P.; Thiry, Y.; Rufyikiri, G.; Delvaux, B.; Declerck, S.

    2008-01-01

    Contamination by uranium (U) occurs principally at U mining and processing sites. Uranium can have tremendous environmental consequences, as it is highly toxic to a broad range of organisms and can be dispersed in both terrestrial and aquatic environments. Remediation strategies of U-contaminated soils have included physical and chemical procedures, which may be beneficial, but are costly and can lead to further environmental damage. Phytoremediation has been proposed as a promising alternative, which relies on the capacity of plants and their associated microorganisms to stabilize or extract contaminants from soils. In this paper, we review the role of a group of plant symbiotic fungi, i.e. arbuscular mycorrhizal fungi, which constitute an essential link between the soil and the roots. These fungi participate in U immobilization in soils and within plant roots and they can reduce root-to-shoot translocation of U. However, there is a need to evaluate these observations in terms of their importance for phytostabilization strategies

  5. Underground resource allocation between individual networks of mycorrhizal fungi

    DEFF Research Database (Denmark)

    Mikkelsen, Bolette Lind; Rosendahl, Søren; Jakobsen, Iver

    2008-01-01

    * Fusions between individual mycelia of arbuscular mycorrhizal (AM) fungi have been observed in two-dimensional systems but never in soil systems. Here, phosphorus ((32)P) labelling was used to demonstrate nutrient transfer between individual mycelia and to investigate the possible role...... of G. mosseae overlapped. The transfer probably occurred via anastomoses between the mycelia as no transfer of (32)P was detected between the mycelia of different fungi at the second harvest. * The indicated ability of AM fungal mycelia to anastomose in soil has implications for the formation of large...... of anastomosis. * Trifolium subterraneum colonized by Glomus mosseae were grown in root-retaining mesh bags, which were placed 20 cm apart. The mycelium of one plant, the donor, had access to (32)P-labelled soil placed adjacent to the mesh bag. Transfer of (32)P from the donor mycelium to the receiver plant...

  6. [Proteome analysis on interaction between Anoectochilus roxburghii and Mycorrhizal fungus].

    Science.gov (United States)

    Gao, Chuan; Guo, Shun-Xing; Zhang, Jing; Chen, Juan; Zhang, Li-Chun

    2012-12-01

    To study the mechanism of plant growing promoted by Mycorrhizal fungus through the difference of proteomes. The differential proteomes between uninoculated and inoculated endophytic fungi, Epulorhiza sp. on Anoectochilus roxburghii were analyzed by two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrum. Twenty-seven protein spots were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Twenty-two candidate proteins were identified by database comparisons. The function of these proteins mostly involved in signal transduction, metabolic regulation, as well as photosynthesis and substance metabolism. The results indicate that the regulator control system of plant is influenced by fungi action, and the positive regulation improves substance metabolism and photosynthesis, which results in strong plant and higher resistance. It is also deduced that silent genes may exist in endosymbiosis plants.

  7. Vesicular-arbuscular mycorrhizal populations in stored topsoil

    Energy Technology Data Exchange (ETDEWEB)

    Harris, J.A.; Hunter, D.; Birch, P.; Short, K.C. (North East London Polytechnic, London (UK). Environment and Industry Research Unit, Dept. of Biology and Biochemistry)

    1987-01-01

    Two soil stores of different ages were sampled to investigate their vesicular-arbuscular mycorrhizal (VAM) populations. The soils collected were assessed for pH, moisture content, loss on ignition, spore numbers, number and size of root fragments present and percentage of these roots infected with VAM. A corn-root bioassay was used to determine soil infectivity. Root fragment number, size, % root infection and soil infectivity were negatively correlated with soil depth. VAM spore number was not significantly correlated with depth in either store. It appears that infected root fragments and fresh roots were the source of inoculum although there may have been a contribution from spores in the younger store. The infectivity of the older store soil was less than that of the younger store. 12 refs., 5 tabs.

  8. Nutrient Exchange and Regulation in Arbuscular Mycorrhizal Symbiosis.

    Science.gov (United States)

    Wang, Wanxiao; Shi, Jincai; Xie, Qiujin; Jiang, Yina; Yu, Nan; Wang, Ertao

    2017-09-12

    Most land plants form symbiotic associations with arbuscular mycorrhizal (AM) fungi. These are the most common and widespread terrestrial plant symbioses, which have a global impact on plant mineral nutrition. The establishment of AM symbiosis involves recognition of the two partners and bidirectional transport of different mineral and carbon nutrients through the symbiotic interfaces within the host root cells. Intriguingly, recent discoveries have highlighted that lipids are transferred from the plant host to AM fungus as a major carbon source. In this review, we discuss the transporter-mediated transfer of carbon, nitrogen, phosphate, potassium and sulfate, and present hypotheses pertaining to the potential regulatory mechanisms of nutrient exchange in AM symbiosis. Current challenges and future perspectives on AM symbiosis research are also discussed. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

  9. Biodiversity of arbuscular mycorrhizal fungi and ecosystem function.

    Science.gov (United States)

    Powell, Jeff R; Rillig, Matthias C

    2018-03-30

    Contents Summary I. pathways of influence and pervasiveness of effects II. AM fungal richness effects on ecosystem functions III. Other dimensions of biodiversity IV. Back to basics - primary axes of niche differentiation by AM fungi V. Functional diversity of AM fungi - a role for biological stoichiometry? VI. Past, novel and future ecosystems VII. Opportunities and the way forward Acknowledgements References SUMMARY: Arbuscular mycorrhizal (AM) fungi play important functional roles in ecosystems, including the uptake and transfer of nutrients, modification of the physical soil environment and alteration of plant interactions with other biota. Several studies have demonstrated the potential for variation in AM fungal diversity to also affect ecosystem functioning, mainly via effects on primary productivity. Diversity in these studies is usually characterized in terms of the number of species, unique evolutionary lineages or complementary mycorrhizal traits, as well as the ability of plants to discriminate among AM fungi in space and time. However, the emergent outcomes of these relationships are usually indirect, and thus context dependent, and difficult to predict with certainty. Here, we advocate a fungal-centric view of AM fungal biodiversity-ecosystem function relationships that focuses on the direct and specific links between AM fungal fitness and consequences for their roles in ecosystems, especially highlighting functional diversity in hyphal resource economics. We conclude by arguing that an understanding of AM fungal functional diversity is fundamental to determine whether AM fungi have a role in the exploitation of marginal/novel environments (whether past, present or future) and highlight avenues for future research. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  10. Selection of Infective Arbuscular Mycorrhizal Fungal Isolates for Field Inoculation

    Directory of Open Access Journals (Sweden)

    Elisa Pellegrino

    2010-09-01

    Full Text Available Arbuscular mycorrhizal (AM fungi play a key role in host plant growth and health, nutrient and water uptake, plant community diversity and dynamics. AM fungi differ in their symbiotic performance, which is the result of the interaction of two fungal characters, infectivity and efficiency. Infectivity is the ability of a fungal isolate to establish rapidly an extensive mycorrhizal symbiosis and is correlated with pre-symbiotic steps of fungal life cycle, such as spore germination and hyphal growth. Here, different AM fungal isolates were tested, with the aim of selecting infective endophytes for field inoculation. Greenhouse and microcosm experiments were performed in order to assess the ability of 12 AM fungal isolates to produce spores, colonize host roots and to perform initial steps of symbiosis establishment, such as spore germination and hyphal growth. AM fungal spore production and root colonization were significantly different among AM fungal isolates. Spore and sporocarp densities ranged from 0.8 to 7.4 and from 0.6 to 2.0 per gram of soil, respectively, whereas root colonization ranged from 2.9 to 72.2%. Percentage of spore or sporocarp germination ranged from 5.8 to 53.3% and hyphal length from 4.7 to 79.8 mm. The ordination analysis (Redundancy Analysis, RDA showed that environmental factors explained about 60% of the whole variance and their effect on fungal infectivity variables was significant (P = 0.002. The biplot clearly showed that variables which might be used to detect infective AM fungal isolates were hyphal length and root colonization. Such analysis may allow the detection of the best parameters to select efficient AM fungal isolates to be used in agriculture.

  11. VA Health Care: VA Spends Millions on Post-Traumatic Stress Disorder Research and Incorporates Research Outcomes into Guidelines and Policy for Post-Traumatic Stress Disorder Services

    Science.gov (United States)

    2011-01-01

    post - traumatic stress disorder ( PTSD ) and...Veterans Affairs (VA) Intramural Post - Traumatic Stress Disorder ( PTSD ) Research Funding and VA’s Medical and Prosthetic Research Appropriation...Table 6: Department of Veterans Affairs (VA) Research Centers and Programs That Conduct or Support Post - Traumatic Stress Disorder ( PTSD ) Research

  12. Effects of nursery preconditioning through mycorrhizal inoculation and drought in Arbutus unedo L. plants.

    Science.gov (United States)

    Navarro García, Alejandra; Del Pilar Bañón Árias, Sebastián; Morte, Asunción; Sánchez-Blanco, María Jesús

    2011-01-01

    The influence of a water deficit treatment and mycorrhizal inoculation with Pisolithus tinctorius (Pers.) Coker and Couch on the water relations, gas exchange, and plant growth in Arbutus unedo L. plants was studied in order to evaluate the hardening process during the nursery period. The ability to withstand the adverse conditions after transplantation was also studied. Mycorrhizal and non-mycorrhizal seedlings of A. unedo were pot-grown for 4 months in a greenhouse (nursery period), during which time two irrigation treatments, well watered (100% water holding capacity, leaching 20% of the applied water) and deficit irrigation (50% of the well watered), were applied. Subsequently, the plants were transplanted to the field and well irrigated (transplanting period), after which and until the end of the experiment they received no water (establishment period). At the end of the nursery period, both water deficit and mycorrhizae were seen to have altered the plant morphology. Mycorrhizal plants had lower leaf area and improved leaf color parameters, while the water deficit increased root dry weight and the root/shoot ratio. Mycorrhizal plants had higher leaf water potential values than non-inoculated plants. Mycorrhizae increased stomatal conductance and photosynthesis values, especially in stressed plants. Drought led to an osmotic adjustment and a decrease in the leaf water potential values at turgor loss point in the mycorrhizal plants. Cell wall rigidity, measured as increased bulk modulus of elasticity, was decreased by the mycorrhizae effect. After transplanting, no differences were found in the water relations or gas exchange values between treatments. During the establishment period, the plants that had been exposed to both drought and mycorrhizae showed a better water status (higher leaf water and turgor potential values) and higher gas exchange values. In conclusion, water deficit and mycorrhizal inoculation of A. unedo plants in nursery produced changes in

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

    Science.gov (United States)

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

    2006-01-01

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

  14. Arbuscular mycorrhizal fungi (AMF) as bio protector agents against wilt induced by Verticillium spp. in pepper

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, N.; Garmendia, I.; Sanchez-Diaz, M.; Aguirreolea, J.

    2010-07-01

    Verticillium dahliae Kleb. is a vascular pathogen that alters water status and growth of pepper plants and causes drastic reductions in yield. Its control is difficult because it can survive in field soil for several years. The application of arbuscular mycorrhizal fungi (AMF) as bio protector agents against V. dahliae is an alternative to the use of chemicals which, in addition, is more respectful with the environment. The establishment of the mutualistic association of plant roots and AMF involves a continuous cellular and molecular dialogue between both symbionts that includes the pre activation of plant defense responses that may enhance the resistance or tolerance of mycorrhizal plants to soil-borne pathogens. Some AMF can improve the resistance of Capsicum annuum L. against V. dahliae. This is especially relevant for pepper cultivars (i.e. cv. Piquillo) that exhibit high susceptibility to this pathogen. Compared with non-mycorrhizal plants, mycorrhizal pepper can exhibit more balanced antioxidant metabolism in leaves along the first month after pathogen inoculation, which may contribute to delay both the development of disease symptoms and the decrease of photosynthesis in Verticillium-inoculated plants with the subsequent benefit for yield. In stems, mycorrhizal pepper show earlier and higher deposition of lignin in xylem vessels than non mycorrhizal plants, even in absence of the pathogen. Moreover, AMF can induce new isoforms of acidic chitinases and superoxide dismutase in roots. Mycorrhizal-specific induction of these enzymatic activities together with enhanced peroxidase and phenylalanine ammonia-lyase in roots may also be involved in the bio protection of Verticillium-induced wilt in pepper by AMF. (Author) 81 refs.

  15. Building capacity in VA to provide emergency gynecology services for women.

    Science.gov (United States)

    Cordasco, Kristina M; Huynh, Alexis K; Zephyrin, Laurie; Hamilton, Alison B; Lau-Herzberg, Amy E; Kessler, Chad S; Yano, Elizabeth M

    2015-04-01

    Visits to Veterans Administration (VA) emergency departments (EDs) are increasingly being made by women. A 2011 national inventory of VA emergency services for women revealed that many EDs have gaps in their resources and processes for gynecologic emergency care. To guide VA in addressing these gaps, we sought to understand factors acting as facilitators and/or barriers to improving VA ED capacity for, and quality of, emergency gynecology care. Semistructured interviews with VA emergency and women's health key informants. ED directors/providers (n=14), ED nurse managers (n=13), and Women Veteran Program Managers (n=13) in 13 VA facilities. Leadership, staff, space, demand, funding, policies, and community were noted as important factors influencing VA EDs building capacity and improving emergency gynecologic care for women Veterans. These factors are intertwined and cross multiple organizational levels so that each ED's capacity is a reflection not only of its own factors, but also those of its local medical center and non-VA community context as well as VA regional and national trends and policies. Policies and quality improvement initiatives aimed at building VA's emergency gynecologic services for women need to be multifactorial and aimed at multiple organizational levels. Policies need to be flexible to account for wide variations across EDs and their medical center and community contexts. Approaches that build and encourage local leadership engagement, such as evidence-based quality improvement methodology, are likely to be most effective.

  16. Can reported VaR be used as an indicator of the volatility of share prices? Evidence from UK banks.

    OpenAIRE

    Ou, Shian Kao

    2006-01-01

    Value at Risk (VaR) is used as an indicator to measure the risks contained in a firm. With the uprising development of VaR theory and computational techniques, the VaR is nowadays adopted by banks and reported in annual reports. Since the method to calculate VaR is questioned, and the reported VaR can not be thoroughly audited, this paper attempts to find the relationship between the reported VaR and the volatility of share price for UK listed banks. This paper reviews literature about VaR an...

  17. Aspen-associated mycorrhizal fungal production and respiration as a function of changing CO2, O3 and climatic variables

    Science.gov (United States)

    Carrie J. Andrew; Linda T.A. van Diepen; R. Michael Miller; Erik A. Lilleskov

    2014-01-01

    The relationships of mycorrhizal fungal respiration and productivity to climate and atmospheric chemistry remain under characterized. We quantified mycorrhizal sporocarp and hyphal respiration, as well as growing season net hyphal production, under ambient and elevated carbon dioxide (CO2) and ozone (O3) in relation to...

  18. Plant-fungus competition for nitrogen erases mycorrhizal growth benefits of Andropogon gerardii under limited nitrogen supply

    Czech Academy of Sciences Publication Activity Database

    Püschel, David; Janoušková, Martina; Hujslová, M.; Slavíková, R.; Gryndlerová, H.; Jansa, J.

    2016-01-01

    Roč. 6, č. 13 (2016), s. 4332-4346 ISSN 2045-7758 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * nutrient uptake response * mycorrhizal benefits and costs Subject RIV: EF - Botanics Impact factor: 2.440, year: 2016

  19. Impact of abiotic factors on development of the community of arbuscular mycorrhizal fungi in the soil: a Review

    Science.gov (United States)

    Jamiołkowska, Agnieszka; Księżniak, Andrzej; Gałązka, Anna; Hetman, Beata; Kopacki, Marek; Skwaryło-Bednarz, Barbara

    2018-01-01

    Arbuscular mycorrhizal fungi inhabiting soil play an important role for vascular plants. Interaction between arbuscular mycorrhizal fungi, plants and soil microorganisms leads to many mutual advantages. However, the effectiveness of mycorrhizal fungi depends not only on biotic, but also abiotic factors such as physico-chemical properties of the soil, availability of water and biogenic elements, agricultural practices, and climatic conditions. First of all, it is important to adapt the arbuscular mycorrhizal fungi species to changing environmental conditions. The compactness of the soil and its structure have a huge impact on its biological activity. Soil pH reaction has a substantial impact on the mobility of ions in soil dilutions and their uptake by plants and soil microflora. Water excess can be a factor negatively affecting arbuscular mycorrhizal fungi because these microorganisms are sensitive to a lower availability of oxygen. Mechanical cultivation of the soil has a marginal impact on the arbuscular mycorrhizal fungi spores. However, soil translocation can cause changes to the population of the arbuscular mycorrhizal fungi abundance in the soil profile. The geographical location and topographic differentiation of cultivated soils, as well as the variability of climatic factors affect the population of the arbuscular mycorrhizal fungi in the soils and their symbiotic activity.

  20. The arbuscular mycorrhizal fungus Rhizophagus irregularis differentially regulates the copper response of two maize cultivars differing in copper tolerance.

    Science.gov (United States)

    Merlos, Miguel A; Zitka, Ondrej; Vojtech, Adam; Azcón-Aguilar, Concepción; Ferrol, Nuria

    2016-12-01

    Arbuscular mycorrhiza can increase plant tolerance to heavy metals. The effects of arbuscular mycorrhiza on plant metal tolerance vary depending on the fungal and plant species involved. Here, we report the effect of the arbuscular mycorrhizal fungus Rhizophagus irregularis on the physiological and biochemical responses to Cu of two maize genotypes differing in Cu tolerance, the Cu-sensitive cv. Orense and the Cu-tolerant cv. Oropesa. Development of the symbiosis confers an increased Cu tolerance to cv. Orense. Root and shoot Cu concentrations were lower in mycorrhizal than in non-mycorrhizal plants of both cultivars. Shoot lipid peroxidation increased with soil Cu content only in non-mycorrhizal plants of the Cu-sensitive cultivar. Root lipid peroxidation increased with soil Cu content, except in mycorrhizal plants grown at 250mg Cu kg -1 soil. In shoots of mycorrhizal plants of both cultivars, superoxide dismutase, ascorbate peroxidase, catalase and glutathione reductase activities were not affected by soil Cu content. In Cu-supplemented soils, total phytochelatin content increased in shoots of mycorrhizal cv. Orense but decreased in cv. Oropesa. Overall, these data suggest that the increased Cu tolerance of mycorrhizal plants of cv. Orense could be due to an increased induction of shoot phytochelatin biosynthesis by the symbiosis in this cultivar. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. Diversity and dynamics of mycorrhizal associations in tropical rain forests with different disturbance regimes in South Cameroon

    NARCIS (Netherlands)

    Onguene, N.A.

    2000-01-01

    The present study documents the occurrence of mycorrhizal associations in the rain forests of south Cameroon. All species investigated are mycorrhizal. Most timber species form arbuscular mycorrhiza, but some timber species, which usually occur in clumps, form ectomycorrhiza. Species

  2. Effects of tree species, water and nitrogen on mycorrhizal C flux

    Science.gov (United States)

    Menyailo, O.; Matvienko, A.

    2012-12-01

    Mycorrhiza plays an important role in global carbon cycle, especially, in forest soils, yet the effect of tree species on the amount and timing of C transfer through roots to myccorhiza is largely unknown. We studied the C transport to mycorrhiza under 6 most commonly dominant in boreal forests tree species using the mesh collars installed at the Siberian afforestation experiment. The CO2 flux from mycorrhizal and non-mycorrhizal mesh collars indicated the mycorrhizal C flux. Tree species strongly differed in C flux to mycorrhiza: more C was transferred by deciduous species than by conifers. The mycorrhizal CO2 flux was not linked to soil temperature but rather to trees phenology and to photosynthetic activity. All tree species transfered more carbon to mycorrhiza during the second half of summer and in September, this is because all the carbon photosynthesized earlier is used for building the tree biomass. Seasonal variation in C transfer to mycorrhiza was much larger than hourly variation (within a day). Nitrogen application (50 kg/ha) increased mycorrhizal C flux only under Scots pine, but not under larch, thus the effect of N application is tree species dependent. We found under most tree species that more C was transferred by trees to mycorrhiza in root-free collars, where the soil moisture was higher than in collars with roots. This suggests that trees preferentially support those parts of mycorrhiza, which can gain extra-resources.

  3. EFFECT OF DIESEL AND BIODIESEL ON THE GROWTH OF Brachiaria decumbens INOCULATED WITH ARBUSCULAR MYCORRHIZAL FUNGI

    Directory of Open Access Journals (Sweden)

    Dora Trejo

    2013-12-01

    Full Text Available Arbuscular mycorrhizal fungi have been found to be associated with plants useful in soil phytoremediation. The aim of this study was to compare the effects of diesel and biodiesel in soil and sand on the growth of Brachiaria decumbens inoculated with mycorrhizae. Two experiments were carried out: one experiment in soil and another in sand. A two-level- factorial design with three factors was used (one on sterile and another on non-sterile soil, with and without mycorrhizae; and one with diesel and another with biodiesel. In sand, a two-factor design with two levels was used (with and without mycorrhizae and with diesel and biodiesel, both with three replications. NOVADIESEL, biodiesel and PEMEX diesel were use as contaminants, both at 7%. The fresh and dry weight of the plants and percentage of mycorrhizal colonization, were assessed 30 days after planting. In soil, biodiesel was more toxic and reduced the fresh and dry weights of plants, especially in non-sterile soil. Biodiesel yielded greater mycorrhizal colonization values that doubled those of the control. In sand, diesel was found to reduce three times the fresh and dry weights of plants, compared to the biodiesel. In sand diesel presented high values of mycorrhizal colonization in comparison with biodiesel.  Plants inoculated with mycorrhizal fungi exhibited better development than non-inoculated plants, even in the presence of contaminants.

  4. Total fatty acid composition in the characterization and identification of orchid mycorrhizal fungi Epulorhiza spp.

    Directory of Open Access Journals (Sweden)

    Marlon Corrêa Pereira

    2011-08-01

    Full Text Available Rhizoctonia-like fungi are the main mycorrhizal fungi in orchid roots. Morphological characterization and analysis of conserved sequences of genomic DNA are frequently employed in the identification and study of fungi diversity. However, phytopathogenic Rhizoctonia-like fungi have been reliably and accurately characterized and identified through the examination of the fatty acid composition. To evaluate the efficacy of fatty acid composition in characterizing and identifying Rhizoctonia-like mycorrhizal fungi in orchids, three Epulorhiza spp. mycorrhizal fungi from Epidendrum secundum, two unidentified fungi isolated from Epidendrum denticulatum, and a phytopathogenic fungus, Ceratorhiza sp. AGC, were grouped based on the profile of their fatty acids, which was assessed by the Euclidian and Mahalanobis distances and the UPGMA method. Dendrograms distinguished the phytopathogenical isolate of Ceratorhiza sp. AGC from the mycorrhizal fungi studied. The symbionts of E. secundum were grouped into two clades, one containing Epulorhiza sp.1 isolates and the other the Epulorhiza sp.2 isolate. The similarity between the symbionts of E. denticulatum and Epulorhiza spp. fungi suggests that symbionts found in E. denticulatum may be identified as Epulorhiza. These results were corroborated by the analysis of the rDNA ITS region. The dendrogram constructed based on the Mahalanobis distance differentiated the clades most clearly. Fatty acid composition analysis proved to be a useful tool for characterizing and identifying Rhizoctonia-like mycorrhizal fungi.

  5. Occurrence of arbuscular mycorrhizal fungi on King George Island, South Shetland Islands, Antarctica.

    Science.gov (United States)

    Barbosa, Marisângela V; Pereira, Elismara A; Cury, Juliano C; Carneiro, Marco A C

    2017-01-01

    Arbuscular mycorrhizal fungi make up an important ecological niche in ecosystems, and knowledge of their diversity in extreme environments is still incipient. The objective of this work was to evaluate the density and diversity of arbuscular mycorrhizal fungi in the soil of King George Island in the South Shetland Islands archipelago, Antarctica. For that, soil and roots of Deschampsia antarctica were collected at the brazilian research station in Antarctica. The spore density, species diversity and mycorrhizal colonization in the roots were evaluated. There was a low density of spores (27.4 ± 17.7) and root mycorrhizal colonization (6 ± 5.1%), which did not present statistical difference. Four species of arbuscular mycorrhizal fungi were identified, distributed in two genera: three species of the genus Glomus (Glomus sp1, Glomus sp2 and Glomus sp3) and one of the genus Acaulospora, which was identified at species level (Acaulospora mellea). Greater soil diversity was verified with pH 5.9 and phosphorus concentration of 111 mg dm-3, occurring two species of genus Glomus and A. mellea. Based on literature data, this may be the first record of this species of Acaulospora mellea in Antarctic soils, colonizing D. antarctica plants.

  6. Uptake of 15 trace elements in arbuscular mycorrhizal marigold measured by the multitracer technique

    International Nuclear Information System (INIS)

    Suzuki, H.; Kumagai, H.; Oohashi, K.; Sakamoto, K.; Inubushi, K.; Enomoto, S.; Ambe, F.

    2000-01-01

    The effect of arbuscular mycorrhizal (AM) colonization on the uptake of trace elements in marigold (Tagetes patula L.) was studied using a multitracer consisting of radionuclides of 7 Be, 22 Na, 46 Sc, 51 Cr, 54 Mn, 59 Fe, 56 Co, 65 Zn, 74 As, 75 Se, 83 Rb, 85 Sr, 88 Y, 88 Zr, and 95m Tc. Marigold plants were grown under controlled environmental conditions in sand culture either without mycorrhizas or in association with an AM fungus, Glomus etunicatum. The multitracer was applied to the pot, and plants were harvested at 7 and 21 d after tracer application. We found that the uptake of 7 Be, 22 Na, 51 Cr, 59 Fe, 65 Zn, and 95m Tc was higher in the mycorrhizal marigolds than in the non-mycorrhizal ones, while that of 46 Sc, 56 Co, 83 Rb, and 85 Sr was lower in the mycorrhizal marigolds than in the non-mycorrhizal ones. Thus, the multitracer technique enabled to analyze the uptake of various elements by plant simultaneously. It is suggested that this technique could be used to analyze the effects of AM colonization on the uptake of trace elements by plant. (author)

  7. Effects of arbuscular mycorrhizal fungi and maternal plant sex on seed germination and early plant establishment.

    Science.gov (United States)

    Varga, Sandra

    2015-03-01

    • Arbuscular mycorrhizal fungi usually enhance overall plant performance, yet their effects on seed germination and early plant establishment, crucial steps in plant cycles, are generally overlooked. In gynodioecious species, sexual dimorphism in these traits has been reported, with females producing seeds that germinate at a faster rate than seeds from hermaphrodites.• Using the gynodioecious plant Geranium sylvaticum, I investigated in a greenhouse experiment whether the presence of arbuscular mycorrhizal spores affects seed germination and early plant establishment, examining at the same time whether the sex of the mother producing the seeds also influences these parameters and whether sex-specific interactions between these two factors exist.• The presence of arbuscular mycorrhizal spores in the soil decreased seed germination, did not affect plant survival, but did increase plant growth. Moreover, no significant differences in seed traits were detected between the sexes of the plants producing the seeds.• This study demonstrates that arbuscular mycorrhizal fungi may have contrasting effects for plants during early life stages and that mycorrhizal effects can take place even at the precolonization stage. © 2015 Botanical Society of America, Inc.

  8. [Arbuscular mycorrhizal symbiosis influences the biological effects of nano-ZnO on maize].

    Science.gov (United States)

    Wang, Wei-Zhong; Wang, Fa-Yuan; Li, Shuai; Liu, Xue-Qin

    2014-08-01

    Engineered nanoparticles (ENPs) can be taken up and accumulated in plants, then enter human bodies via food chain, and thus cause potential health risk. Arbuscular mycorrhizal fungi form mutualistic symbioses with the majority of higher plants in terrestrial ecosystems, and potentially influence the biological effects of ENPs. The present greenhouse pot culture experiment studied the effects of inoculation with or without arbuscular mycorrhizal fungus Acaulospora mellea on growth and nutritional status of maize under different nano-ZnO levels (0, 500, 1 000, 2000 and 3 000 mg x kg(-1)) artificially added into soil. Results showed that with the increasing nano-ZnO levels in soil, mycorrhizal colonization rate and biomass of maize plants showed a decreasing trend, total root length, total surface area and total volume reduced, while Zn concentration and uptake in plants gradually increased, and P, N, K, Fe, and Cu uptake in shoots all decreased. Compared with the controls, arbuscular mycorrhizal inoculation improved the growth and P, N and K nutrition of maize, enhanced total root length, total surface area and total volume, and increased Zn allocation to roots when nano-ZnO was added. Our results firstly show that nano-ZnO in soil induces toxicity to arbuscular mycorrhizae, while arbuscular mycorrhizal inoculation can alleviate its toxicity and play a protective role in plants.

  9. Arbuscular mycorrhizal fungi alleviate arsenic toxicity to Medicago sativa by influencing arsenic speciation and partitioning.

    Science.gov (United States)

    Li, Jinglong; Sun, Yuqing; Jiang, Xuelian; Chen, Baodong; Zhang, Xin

    2018-08-15

    In a pot experiment, Medicago sativa inoculated with/without arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis were grown in four levels (0, 10, 25, and 75 mg/kg) of arsenic (As)-polluted soil to investigate the influences of AM symbiosis on plant As tolerance. The results showed that mycorrhizal inoculation significantly increased plant biomass, while As addition decreased mycorrhizal colonization and hyphal length density. Mycorrhizal inoculation dramatically improved plant phosphorus (P) nutrition, restricted As uptake and retained more As in roots by upregulating the expression of the AM-induced P transporter gene MsPT4 and the metallothionein gene MsMT2. High soil As content downregulated MsPT4 expression. Dimethylarsenic acid (DMA) was detected only in the shoots of mycorrhizal plants, indicating that AM fungi likely play an essential role in As detoxification by biological methylation. The present investigation allowed deeper insights into the As detoxification mechanisms of AM associations and demonstrated the important role of AM fungi in plant resistance under As-contaminated conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Gr and hp-1 tomato mutants unveil unprecedented interactions between arbuscular mycorrhizal symbiosis and fruit ripening.

    Science.gov (United States)

    Chialva, Matteo; Zouari, Inès; Salvioli, Alessandra; Novero, Mara; Vrebalov, Julia; Giovannoni, James J; Bonfante, Paola

    2016-07-01

    Systemic responses to an arbuscular mycorrhizal fungus reveal opposite phenological patterns in two tomato ripening mutants depending whether ethylene or light reception is involved. The availability of tomato ripening mutants has revealed many aspects of the genetics behind fleshy fruit ripening, plant hormones and light signal reception. Since previous analyses revealed that arbuscular mycorrhizal symbiosis influences tomato berry ripening, we wanted to test the hypothesis that an interplay might occur between root symbiosis and fruit ripening. With this aim, we screened seven tomato mutants affected in the ripening process for their responsiveness to the arbuscular mycorrhizal fungus Funneliformis mosseae. Following their phenological responses we selected two mutants for a deeper analysis: Green ripe (Gr), deficient in fruit ethylene perception and high-pigment-1 (hp-1), displaying enhanced light signal perception throughout the plant. We investigated the putative interactions between ripening processes, mycorrhizal establishment and systemic effects using biochemical and gene expression tools. Our experiments showed that both mutants, notwithstanding a normal mycorrhizal phenotype at root level, exhibit altered arbuscule functionality. Furthermore, in contrast to wild type, mycorrhization did not lead to a higher phosphate concentration in berries of both mutants. These results suggest that the mutations considered interfere with arbuscular mycorrhiza inducing systemic changes in plant phenology and fruits metabolism. We hypothesize a cross talk mechanism between AM and ripening processes that involves genes related to ethylene and light signaling.

  11. Phosphate Uptake from Phytate Due to Hyphae-Mediated Phytase Activity by Arbuscular Mycorrhizal Maize.

    Science.gov (United States)

    Wang, Xin-Xin; Hoffland, Ellis; Feng, Gu; Kuyper, Thomas W

    2017-01-01

    Phytate is the most abundant form of soil organic phosphorus (P). Increased P nutrition of arbuscular mycorrhizal plants derived from phytate has been repeatedly reported. Earlier studies assessed acid phosphatase rather than phytase as an indication of mycorrhizal fungi-mediated phytate use. We investigated the effect of mycorrhizal hyphae-mediated phytase activity on P uptake by maize. Two maize ( Zea mays L.) cultivars, non-inoculated or inoculated with the arbuscular mycorrhizal fungi Funneliformis mosseae or Claroideoglomus etunicatum , were grown for 45 days in two-compartment rhizoboxes, containing a root compartment and a hyphal compartment. The soil in the hyphal compartment was supplemented with 20, 100, and 200 mg P kg -1 soil as calcium phytate. We measured activity of phytase and acid phosphatase in the hyphal compartment, hyphal length density, P uptake, and plant biomass. Our results showed: (1) phytate addition increased phytase and acid phosphatase activity, and resulted in larger P uptake and plant biomass; (2) increases in P uptake and biomass were correlated with phytase activity but not with acid phosphatase activity; (3) lower phytate addition rate increased, but higher addition rate decreased hyphal length density. We conclude that P from phytate can be taken up by arbuscular mycorrhizal plants and that phytase plays a more important role in mineralizing phytate than acid phosphatase.

  12. Chromium immobilization by extra- and intraradical fungal structures of arbuscular mycorrhizal symbioses.

    Science.gov (United States)

    Wu, Songlin; Zhang, Xin; Sun, Yuqing; Wu, Zhaoxiang; Li, Tao; Hu, Yajun; Lv, Jitao; Li, Gang; Zhang, Zhensong; Zhang, Jing; Zheng, Lirong; Zhen, Xiangjun; Chen, Baodong

    2016-10-05

    Arbuscular mycorrhizal (AM) fungi can enhance plant Cr tolerance through immobilizing Cr in mycorrhizal roots. However, the detailed processes and mechanisms are unclear. The present study focused on cellular distribution and speciation of Cr in both extraradical mycelium (ERM) and mycorrhizal roots exposed to Cr(VI) by using field emission scanning electron microscopy equipped with energy dispersive X-ray spectrometer (FE-SEM-EDS), scanning transmission soft X-ray microscopy (STXM) and X-ray absorption fine structure (XAFS) spectroscopy techniques. We found that amounts of particles (possibly extracellular polymeric substances, EPS) were produced on the AM fungal surface upon Cr(VI) stress, which contributed greatly to Cr(VI) reduction and immobilization. With EDS of the surface of AM fungi exposed to various Cr(VI) levels, a positive correlation between Cr and P was revealed, suggesting that phosphate groups might act as counter ions of Cr(III), which was also confirmed by the XAFS analysis. Besides, STXM and XAFS analyses showed that Cr(VI) was reduced to Cr(III) in AM fungal structures (arbuscules, intraradical mycelium, etc.) and cell walls in mycorrhizal roots, and complexed possibly with carboxyl groups or histidine analogues. The present work provided evidence of Cr immobilization on fungal surface and in fungal structures in mycorrhizal roots at a cellular level, and thus unraveled the underlying mechanisms by which AM symbiosis immobilize Cr. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Do fungivores trigger the transfer of protective metabolites from host plants to arbuscular mycorrhizal hyphae?

    Science.gov (United States)

    Duhamel, Marie; Pel, Roel; Ooms, Astra; Bücking, Heike; Jansa, Jan; Ellers, Jacintha; van Straalen, Nico M; Wouda, Tjalf; Vandenkoornhuyse, Philippe; Kiers, E Toby

    2013-09-01

    A key objective in ecology is to understand how cooperative strategies evolve and are maintained in species networks. Here, we focus on the tri-trophic relationship between arbuscular mycorrhizal (AM) fungi, host plants, and fungivores to ask if host plants are able to protect their mutualistic mycorrhizal partners from being grazed. Specifically, we test whether secondary metabolites are transferred from hosts to fungal partners to increase their defense against fungivores. We grew Plantago lanceolata hosts with and without mycorrhizal inoculum, and in the presence or absence of fungivorous springtails. We then measured fungivore effects on host biomass and mycorrhizal abundance (using quantitative PCR) in roots and soil. We used high-performance liquid chromatography to measure host metabolites in roots, shoots, and hyphae, focusing on catalpol, aucubin, and verbascoside. Our most striking result was that the metabolite catalpol was consistently found in AM fungal hyphae in host plants exposed to fungivores. When fungivores were absent, catalpol was undetectable in hyphae. Our results highlight the potential for plant-mediated protection of the mycorrhizal hyphal network.

  14. Lead tolerance of Populus nigra in symbiosis with arbuscular mycorrhizal fungi in relation to physiological parameters

    International Nuclear Information System (INIS)

    Salehi, A.; Tabari, M.; Mohammadi Goltapeh, E.; Shirvani, A.

    2016-01-01

    With the aim to examine lead tolerance of Populus nigra (clone 62/154) in symbiosis witharbuscular mycorrhizal fungi, a greenhouse experiment was carried out in a factorial randomized complete scheme with two factors 1) fungal inoculation in 4 levels (control, inoculation with Glomus mosseae, inoculation with G. intraradices and inoculation with G. mosseae+G. intraradices) and 2) lead in 4 levels (0, 100, 500 and 1000 mg kg-1 soil). Mycorrhizal colonization and physiological parameters of plants were measured at the end of growth season. Results showed that at all Pb levels, the percentage of root mycorrhizal colonization in fungal treatments was significantly higher than that in control treatment (without fungal inoculation), however without significant differences between 3 fungal treatments. Pb treatments had no significant effect on root mycorrhizal colonization of P. nigra plants. Also, photosynthesis, stomatal conductance, transpiration, intercellular CO2 concentration and water use efficiency of P. nigra plants had no significant inhibitory effects versus the control found under Pb and fungal treatments or their interaction.The results of present study demonstrated that fungal treatments had no significant effects on physiological parameters and Pb tolerance of P. nigraplants. While, in relation to mycorrhizal colonization and physiological parameters, P. nigra clone 62/154 showeda good tolerance to Pb stress. So, in further investigations of phytoremediation of lead-contaminated soils, this clone can be considered as a proposed species.

  15. Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees.

    Science.gov (United States)

    Chen, Weile; Koide, Roger T; Adams, Thomas S; DeForest, Jared L; Cheng, Lei; Eissenstat, David M

    2016-08-02

    Photosynthesis by leaves and acquisition of water and minerals by roots are required for plant growth, which is a key component of many ecosystem functions. Although the role of leaf functional traits in photosynthesis is generally well understood, the relationship of root functional traits to nutrient uptake is not. In particular, predictions of nutrient acquisition strategies from specific root traits are often vague. Roots of nearly all plants cooperate with mycorrhizal fungi in nutrient acquisition. Most tree species form symbioses with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. Nutrients are distributed heterogeneously in the soil, and nutrient-rich "hotspots" can be a key source for plants. Thus, predicting the foraging strategies that enable mycorrhizal root systems to exploit these hotspots can be critical to the understanding of plant nutrition and ecosystem carbon and nutrient cycling. Here, we show that in 13 sympatric temperate tree species, when nutrient availability is patchy, thinner root species alter their foraging to exploit patches, whereas thicker root species do not. Moreover, there appear to be two distinct pathways by which thinner root tree species enhance foraging in nutrient-rich patches: AM trees produce more roots, whereas EM trees produce more mycorrhizal fungal hyphae. Our results indicate that strategies of nutrient foraging are complementary among tree species with contrasting mycorrhiza types and root morphologies, and that predictable relationships between below-ground traits and nutrient acquisition emerge only when both roots and mycorrhizal fungi are considered together.

  16. Correlation of arbuscular mycorrhizal colonization with plant growth, nodulation, and shoot npk in legumes

    International Nuclear Information System (INIS)

    Javaid, A.; Anjum, T.; Shah, M.H.M.

    2007-01-01

    Correlation of arbuscular mycorrhizal colonization with different root and shoot growth, nodulation and shoot NPK parameters was studied in three legumes viz. Trifolium alexandrianum, Medicago polymorpha and Melilotus parviflora. The three test legume species showed different patterns of root and shoot growth, nodulation, mycorrhizal colonization and shoot N, P and K content. Different mycorrhizal structures viz. mycelium, arbuscules and vesicles showed different patters of correlation with different studied parameters. Mycelial infection showed an insignificantly positive correlation with root and shoot dry biomass and total root length. Maximum root length was however, negatively associated with mycelial infection. Both arbuscular and vesicular infections were negatively correlated with shoot dry biomass and different parameters of root growth. The association between arbuscular infection and maximum root length was significant. All the three mycorrhizal structures showed a positive correlation with number and biomass of nodules. The association between arbuscular infection and nodule number was significant. Mycelial infection was positively correlated with percentage and total shoot N and P. Similarly percentage N was also positively correlated with arbuscular and vesicular infections. By contrast, total shoot N showed a negative association with arbuscular as well as vesicular infections. Similarly both percentage and total shoot P were negatively correlated with arbuscular and vesicular infections. All the associations between mycorrhizal parameters and shoot K were negative except between vesicular infection and shoot %K. (author)

  17. Rhizobial Nodulation Factors Stimulate Mycorrhizal Colonization of Nodulating and Nonnodulating Soybeans.

    Science.gov (United States)

    Xie, Z. P.; Staehelin, C.; Vierheilig, H.; Wiemken, A.; Jabbouri, S.; Broughton, W. J.; Vogeli-Lange, R.; Boller, T.

    1995-08-01

    Legumes form tripartite symbiotic associations with noduleinducing rhizobia and vesicular-arbuscular mycorrhizal fungi. Co-inoculation of soybean (Glycine max [L.] Merr.) roots with Bradyrhizobium japonicum 61-A-101 considerably enhanced colonization by the mycorrhizal fungus Glomus mosseae. A similar stimulatory effect on mycorrhizal colonization was also observed in nonnodulating soybean mutants when inoculated with Bradyrhizobium japonicum and in wild-type soybean plants when inoculated with ineffective rhizobial strains, indicating that a functional rhizobial symbiosis is not necessary for enhanced mycorrhiza formation. Inoculation with the mutant Rhizobium sp. NGR[delta]nodABC, unable to produce nodulation (Nod) factors, did not show any effect on mycorrhiza. Highly purified Nod factors also increased the degree of mycorrhizal colonization. Nod factors from Rhizobium sp. NGR234 differed in their potential to promote fungal colonization. The acetylated factor NodNGR-V (MeFuc, Ac), added at concentrations as low as 10-9 M, was active, whereas the sulfated factor, NodNGR-V (MeFuc, S), was inactive. Several soybean flavonoids known to accumulate in response to the acetylated Nod factor showed a similar promoting effect on mycorrhiza. These results suggest that plant flavonoids mediate the Nod factor-induced stimulation of mycorrhizal colonization in soybean roots.

  18. An integrated functional approach to dissect systemic responses in maize to arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Gerlach, Nina; Schmitz, Jessica; Polatajko, Aleksandra; Schlüter, Urte; Fahnenstich, Holger; Witt, Sandra; Fernie, Alisdair R; Uroic, Kalle; Scholz, Uwe; Sonnewald, Uwe; Bucher, Marcel

    2015-08-01

    Most terrestrial plants benefit from the symbiosis with arbuscular mycorrhizal fungi (AMF) mainly under nutrient-limited conditions. Here the crop plant Zea mays was grown with and without AMF in a bi-compartmented system separating plant and phosphate (Pi) source by a hyphae-permeable membrane. Thus, Pi was preferentially taken up via the mycorrhizal Pi uptake pathway while other nutrients were ubiquitously available. To study systemic effects of mycorrhizal Pi uptake on leaf status, leaves of these plants that display an increased biomass in the presence of AMF were subjected to simultaneous ionomic, transcriptomic and metabolomic analyses. We observed robust changes of the leaf elemental composition, that is, increase of P, S and Zn and decrease of Mn, Co and Li concentration in mycorrhizal plants. Although changes in anthocyanin and lipid metabolism point to an improved P status, a global increase in C versus N metabolism highlights the redistribution of metabolic pools including carbohydrates and amino acids. Strikingly, an induction of systemic defence gene expression and concomitant accumulation of secondary metabolites such as the terpenoids alpha- and beta-amyrin suggest priming of mycorrhizal maize leaves as a mycorrhiza-specific response. This work emphasizes the importance of AM symbiosis for the physiological status of plant leaves and could lead to strategies for optimized breeding of crop species with high growth potential. © 2015 John Wiley & Sons Ltd.

  19. V.A. Gorodtsov and Kazan: tour 1920

    Directory of Open Access Journals (Sweden)

    Kuzminykh Sergey V.

    2014-12-01

    Full Text Available A fragment of an archival document is published, that is connected to the September 8-12, 1920, stay in Kazan of V.A. Gorodtsov, who headed the Archaeological Subdepartment with the Museum Department of the RSFSR People’s Commissariat for Education, in the framework of his inspecting tour around the towns of the Volga and Urals region. The document is a diary, and its entries reflect information about the tour and its results that had not been exhaustively reflected in official documentation. It narrates about meetings, polemic exchanges, Gorodtsov’s addresses to scientists and the public, his impressions of the archaeological investigations in the regions, and the state of the museums and collections. V.A. Gorodtsov’s encounters and personal contacts with B.F. Adler, N.F. Katanov, M.G. Hudyakov and other researchers had played a positive role in archaeology development in the Volga-Kama region during the hardest times after the revolution.

  20. The interplay between P uptake pathways in mycorrhizal peas: a combined physiological and gene‐silencing approach

    DEFF Research Database (Denmark)

    Grønlund, Mette; Albrechtsen, Merete Tryde; Johansen, Ida Elisabeth

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF) have a key role in plant phosphate (Pi) uptake by their efficient capture of soil phosphorus (P) that is transferred to the plant via Pi transporters in the root cortical cells. The activity of this mycorrhizal Pi uptake pathway is often associated with downregu......Arbuscular mycorrhizal fungi (AMF) have a key role in plant phosphate (Pi) uptake by their efficient capture of soil phosphorus (P) that is transferred to the plant via Pi transporters in the root cortical cells. The activity of this mycorrhizal Pi uptake pathway is often associated...... with downregulation of Pi transporter genes in the direct Pi uptake pathway. As the total Pi taken up by the plant is determined by the combined activity of mycorrhizal and direct pathways, it is important to understand the interplay between these, in particular the actual activity of the pathways. To study...

  1. Characteristics Associated With Utilization of VA and Non-VA Care Among Iraq and Afghanistan Veterans With Post-Traumatic Stress Disorder.

    Science.gov (United States)

    Finley, Erin P; Mader, Michael; Bollinger, Mary J; Haro, Elizabeth K; Garcia, Hector A; Huynh, Alexis K; Pugh, Jacqueline A; Pugh, Mary Jo

    2017-11-01

    Post-traumatic stress disorder (PTSD) affects nearly one-fifth of Iraq and Afghanistan Veterans (IAV). The Department of Veterans Affairs (VA) has invested in making evidence-based psychotherapies for PTSD available at every VA facility nationwide; however, an unknown number of veterans opt to receive care in the community rather than with VA. We compared PTSD care utilization patterns among Texas IAV with PTSD, an ethnically, geographically, and economically diverse group. To identify IAV in Texas with service-connected disability for PTSD, we used a crosswalk of VA administrative data from the Operation Enduring Freedom/Operation Iraqi Freedom Roster and service-connected disability data from the Veterans Benefits Administration. We then surveyed a random sample of 1,128 veterans from the cohort, stratified by sex, rurality, and past use/nonuse of any VA care. Respondents were classified into current utilization groups (VA only, non-VA only, dual care, and no professional PTSD treatment) on the basis of reported PTSD care in the prior 12 months. Responses were weighted to account for sample stratification and for response rate within each strata. Utilization group characteristics were compared to the population mean using the one sample Z-test for proportions, or the t-test for means. A multinomial logistic regression model was used to identify survey variables significantly associated with current utilization group. 249 IAV completed the survey (28.4% response rate). Respondents reported receiving PTSD care: in the VA only (58.3%); in military or community-based settings (including private practitioners) (non-VA only, 8.7%); and in both VA and non-VA settings (dual care, 14.5%). The remainder (18.5%) reported no professional PTSD care in the prior year. Veterans ineligible for Department of Defense care, uncomfortable talking about their problems, and opposed to medication were more likely to receive non-VA care only, whereas those with lower household income

  2. Host Plant Physiology and Mycorrhizal Functioning Shift across a Glacial through Future [CO2] Gradient1[OPEN

    Science.gov (United States)

    Mullinix, George W.R.; Ward, Joy K.

    2016-01-01

    Rising atmospheric carbon dioxide concentration ([CO2]) may modulate the functioning of mycorrhizal associations by altering the relative degree of nutrient and carbohydrate limitations in plants. To test this, we grew Taraxacum ceratophorum and Taraxacum officinale (native and exotic dandelions) with and without mycorrhizal fungi across a broad [CO2] gradient (180–1,000 µL L−1). Differential plant growth rates and vegetative plasticity were hypothesized to drive species-specific responses to [CO2] and arbuscular mycorrhizal fungi. To evaluate [CO2] effects on mycorrhizal functioning, we calculated response ratios based on the relative biomass of mycorrhizal (MBio) and nonmycorrhizal (NMBio) plants (RBio = [MBio − NMBio]/NMBio). We then assessed linkages between RBio and host physiology, fungal growth, and biomass allocation using structural equation modeling. For T. officinale, RBio increased with rising [CO2], shifting from negative to positive values at 700 µL L−1. [CO2] and mycorrhizal effects on photosynthesis and leaf growth rates drove shifts in RBio in this species. For T. ceratophorum, RBio increased from 180 to 390 µL L−1 and further increases in [CO2] caused RBio to shift from positive to negative values. [CO2] and fungal effects on plant growth and carbon sink strength were correlated with shifts in RBio in this species. Overall, we show that rising [CO2] significantly altered the functioning of mycorrhizal associations. These symbioses became more beneficial with rising [CO2], but nonlinear effects may limit plant responses to mycorrhizal fungi under future [CO2]. The magnitude and mechanisms driving mycorrhizal-CO2 responses reflected species-specific differences in growth rate and vegetative plasticity, indicating that these traits may provide a framework for predicting mycorrhizal responses to global change. PMID:27573369

  3. KENO V.a Primer: A Primer for Criticality Calculations with SCALE/KENO V.a Using CSPAN for Input

    International Nuclear Information System (INIS)

    Busch, R.D.

    2003-01-01

    The SCALE (Standardized Computer Analyses for Licensing Evaluation) computer software system developed at Oak Ridge National Laboratory (ORNL) is widely used and accepted around the world for criticality safety analyses. The well-known KENO V.a three-dimensional Monte Carlo criticality computer code is the primary criticality safety analysis tool in SCALE. The KENO V.a primer is designed to help a new user understand and use the SCALE/KENO V.a Monte Carlo code for nuclear criticality safety analyses. It assumes that the user has a college education in a technical field. There is no assumption of familiarity with Monte Carlo codes in general or with SCALE/KENO V.a in particular. The primer is designed to teach by example, with each example illustrating two or three features of SCALE/KENO V.a that are useful in criticality analyses. The primer is based on SCALE 4.4a, which includes the Criticality Safety Processor for Analysis (CSPAN) input processor for Windows personal computers (PCs). A second edition of the primer, which uses the new KENO Visual Editor, is currently under development at ORNL and is planned for publication in late 2003. Each example in this first edition of the primer uses CSPAN to provide the framework for data input. Starting with a Quickstart section, the primer gives an overview of the basic requirements for SCALE/KENO V.a input and allows the user to quickly run a simple criticality problem with SCALE/KENO V.a. The sections that follow Quickstart include a list of basic objectives at the beginning that identifies the goal of the section and the individual SCALE/KENO V.a features which are covered in detail in the example problems in that section. Upon completion of the primer, a new user should be comfortable using CSPAN to set up criticality problems in SCALE/KENO V.a

  4. Job satisfaction and burnout among VA and community mental health workers.

    Science.gov (United States)

    Salyers, Michelle P; Rollins, Angela L; Kelly, Yu-Fan; Lysaker, Paul H; Williams, Jane R

    2013-03-01

    Building on two independent studies, we compared burnout and job satisfaction of 66 VA staff and 86 community mental health center staff in the same city. VA staff reported significantly greater job satisfaction and accomplishment, less emotional exhaustion and lower likelihood of leaving their job. Sources of work satisfaction were similar (primarily working with clients, helping/witnessing change). VA staff reported fewer challenges with job-related aspects (e.g. flexibility, pay) but more challenges with administration. Community mental health administrators and policymakers may need to address job-related concerns (e.g. pay) whereas VA administrators may focus on reducing, and helping workers navigate, administrative policies.

  5. Helman defends decision to pull VA sponsorship of Veterans day parade

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2013-04-01

    Full Text Available No abstract available. Article truncated after 150 words. Sharon Helman, Phoenix VA Director, defended her decision to cancel VA sponsorship of the annual Phoenix Veterans Day Parade in a 4/10/13 email to VA employees. Helman said that VA sponsorship was cancelled because of “…priorities in the organization (specifically access, and heightened awareness over liability concerns which VA Legal Counsel brought forward”. She concluded her letter by warning “… that all media inquiries should be forwarded to Paul Coupaud, Acting Public Affairs Officer”. VA officials initially said fear of litigation prompted the review of VA support. Last year, a float carrying wounded Veterans in a Midland, Texas, parade collided with a freight train, killing four and injuring 17. Crash victims and their families filed lawsuits in Texas against Union Pacific Railroad and the float owner. The VA was not a defendant, and the VA has not issued any national directives on liability as a result of the tragedy.In…

  6. Diversity of arbuscular mycorrhizal fungi in grassland spontaneously developed on area polluted by a fertilizer plant

    International Nuclear Information System (INIS)

    Renker, C.; Blanke, V.; Buscot, F.

    2005-01-01

    Mycorrhizal colonization and diversity of arbuscular mycorrhizal fungi (AMF) were analyzed in a calcareous grassland with residual phosphate contamination 10 years after the closure of a pollutant fertilizer plant in Thuringia (Germany). AMF were detected in 21 of 22 plant species analyzed. Mean mycorrhization levels reached up to 74.5% root length colonized. AMF diversity was analyzed based on 104 sequences of the internal transcribed spacer (ITS) of the ribosomal DNA. Phylogenetic analyses revealed a total of 6 species all belonging to the genus Glomus. There was no overlap between species detected as active mycorrhizas on roots (2 taxa) or as spores (4 taxa). Compared to the regional context, the diversity of AMF at our field site was reduced, which may reflect a residual disturbance effect. However, none of the detected species was exclusive to the polluted site as they are commonly found in the region. - Almost all plant species were mycorrhizal

  7. Water management, rice varieties and mycorrhizal inoculation influence arsenic concentration and speciation in rice grains.

    Science.gov (United States)

    Zhang, Xin; Wu, Songlin; Ren, Baihui; Chen, Baodong

    2016-05-01

    A pot experiment was carried out to investigate the effects of water management and mycorrhizal inoculation on arsenic (As) uptake by two rice varieties, the As-resistant BRRI dhan 47 (B47) and As-sensitive BRRI dhan 29 (B29). Grain As concentration of B47 plants was significantly lower than that of B29, and grain As concentration of B47 was higher under flooding conditions than that under aerobic conditions. In general, mycorrhizal inoculation (Rhizophagus irregularis) had no significant effect on grain As concentrations, but decreased the proportion of inorganic arsenic (iAs) in grains of B47. The proportion of dimethylarsinic acid (DMA) in the total grain As was dramatically higher under flooding conditions. Results demonstrate that rice variety selection and appropriate water management along with mycorrhizal inoculation could be practical countermeasures to As accumulation and toxicity in rice grains, thus reducing health risks of As exposure in rice diets.

  8. Effect of arbuscular mycorrhizal fungi and pesticides on Cynara cardunculus growth

    Directory of Open Access Journals (Sweden)

    M. MARIN

    2008-12-01

    Full Text Available Wild cardoon (Cynara cardunculus L. is a promising crop for biomass production. A nursery trial was conducted to investigate the effectiveness of mycorrhizal inoculation on the biomass yield of wild cardoon seedlings and the effect of the pesticides fosetyl-Al, folpet and propamocarb, as fungicides, and isofenphos, phoxim and oxamyl, as insecticides, on cardoon plant growth and the mycorrhization. The arbuscular mycorrhizal (AM fungi inocula were: commercial inoculum with Glomus mosseae spores, and an inoculum of a Glomus sp. strain (AMF-i isolated locally. Mycorrhizal inoculation with either inoculum increased cardoon shoot biomass compared to non-inoculated control plants. The pesticide applications had a neutral or positive effect on cardoon seedling growth. However, the AM fungi colonisation did not decrease except for plants colonised by G. mosseae and treated with the insecticides isofenphos and oxamyl. Thus, the mycorrhiza can survive to pesticide concentrations employed in commercial nursery, and enhance cardoon plant productivity.

  9. How arbuscular mycorrhizal fungi influence the defense system of sunflower during different abiotic stresses.

    Science.gov (United States)

    Mayer, Zoltán; Duc, Nguyen Hong; Sasvári, Zita; Posta, Katalin

    2017-12-01

    The association between terrestrial plants and arbuscular mycorrhizal (AM) fungi is one of the most common and widespread mutualistic plant-fungi interaction. AM fungi are of beneficial effects on the water and nutrient uptake of plants and increase plant defense mechanisms to alleviate different stresses. The aim of this study was to determine the level of polyphenol oxidase (PPO), guaiacol peroxidase (POX) and glutathione S-transferase (GST) enzyme activities and to track the expression of glutathione S-transferase (GST) gene in plant-arbuscular mycorrhizal system under temperature- and mechanical stress conditions. Our results suggest that induced tolerance of mycorrhizal sunflower to high temperature may be attributed to the induction of GST, POX and PPO enzyme activities as well as to the elevated expression of GST. However, the degree of tolerance of the plant is significantly influenced by the age which is probably justified by the energy considerations.

  10. Mycorrhizal colonisation of highbush blueberry and its native relatives in central Finland

    Directory of Open Access Journals (Sweden)

    A. KASURINEN

    2008-12-01

    Full Text Available Transmission electromicroscopy, trypan blue staining in combination with stereomicroscope analysis and biochemical ergosterol assay were used to study the mycorrhizal symbionts in wild bilberry (Vaccinium myrtillus, bog whortleberry (Vaccinium uliginosum and highbush blueberry (Vaccinium corymbosum roots. TEM-analysis showed that in all species ericoid mycorrhizas formed hyphae coil inside the epidermal root cells. In stereomicroscopic viewing the highest mycorrhizal colonisation was observed in the roots of wild bilberries (51%, whereas according to the ergosterol assay the highest total fungal biomass of roots was found in bog whortleberries (209 mg g-1 of root d. wt. Both ergosterol and microscopical method showed that the mycorrhizal associations in blueberry cultivars and their wild relatives growing on natural soil medium are frequent, although ericoid mycorrhiza formation of highbush blueberries was somewhat weaker than that of wild bilberries and bog whortleberries.

  11. Effects of vesicular-arbuscular mycorrhizal (VAM) fungi on the seedling growth of three Pistacia species.

    Science.gov (United States)

    Caglar, S; Akgun, A

    2006-07-01

    The experiment was undertaken to test the efficiency of inoculation of vesicular-arbuscular mycorrhizal (VAM) fungi on the seedling growth of three Pistacia species used as rootstocks. The stratified Pistacia seeds were inoculated with VAM fungi. The highest rate of inoculated roots was 96.7% in P. khinjuck seedlings with G. clarum and G. etunicatum, 83.3% in P. vera seedlings with G. caledonium and 73.3% in P. terebinthus seedlings with G. caledonium. Mycorrhizal inoculations improved seedling height only in P. terebinthus. Certain mycorrhizal inoculations increased the leaf N, but not P and K contents. Seedlings inoculated with G. caledonium had higher reducing sugar contents. It was concluded that pre-inoculated Pistacia seedlings could have a better growth in the harsh field conditions.

  12. Inter-plant communication through mycorrhizal networks mediates complex adaptive behaviour in plant communities.

    Science.gov (United States)

    Gorzelak, Monika A; Asay, Amanda K; Pickles, Brian J; Simard, Suzanne W

    2015-05-15

    Adaptive behaviour of plants, including rapid changes in physiology, gene regulation and defence response, can be altered when linked to neighbouring plants by a mycorrhizal network (MN). Mechanisms underlying the behavioural changes include mycorrhizal fungal colonization by the MN or interplant communication via transfer of nutrients, defence signals or allelochemicals. We focus this review on our new findings in ectomycorrhizal ecosystems, and also review recent advances in arbuscular mycorrhizal systems. We have found that the behavioural changes in ectomycorrhizal plants depend on environmental cues, the identity of the plant neighbour and the characteristics of the MN. The hierarchical integration of this phenomenon with other biological networks at broader scales in forest ecosystems, and the consequences we have observed when it is interrupted, indicate that underground 'tree talk' is a foundational process in the complex adaptive nature of forest ecosystems. Published by Oxford University Press on behalf of the Annals of Botany Company.

  13. Chromium immobilization by extra- and intraradical fungal structures of arbuscular mycorrhizal symbioses

    International Nuclear Information System (INIS)

    Wu, Songlin; Zhang, Xin; Sun, Yuqing; Wu, Zhaoxiang; Li, Tao; Hu, Yajun; Lv, Jitao; Li, Gang; Zhang, Zhensong; Zhang, Jing; Zheng, Lirong; Zhen, Xiangjun

    2016-01-01

    Highlights: • Cr immobilization in AM symbioses revealed by SEM-EDS, STXM and XAFS. • EPS like particles formed on fungal surface upon Cr(VI) stress. • Cr(VI) was reduced to mainly Cr(III)-phosphate analogues on fungal surface. • Cr can be retained by the intraradical fungal structures in mycorrhizal roots. - Abstract: Arbuscular mycorrhizal (AM) fungi can enhance plant Cr tolerance through immobilizing Cr in mycorrhizal roots. However, the detailed processes and mechanisms are unclear. The present study focused on cellular distribution and speciation of Cr in both extraradical mycelium (ERM) and mycorrhizal roots exposed to Cr(VI) by using field emission scanning electron microscopy equipped with energy dispersive X-ray spectrometer (FE-SEM-EDS), scanning transmission soft X-ray microscopy (STXM) and X-ray absorption fine structure (XAFS) spectroscopy techniques. We found that amounts of particles (possibly extracellular polymeric substances, EPS) were produced on the AM fungal surface upon Cr(VI) stress, which contributed greatly to Cr(VI) reduction and immobilization. With EDS of the surface of AM fungi exposed to various Cr(VI) levels, a positive correlation between Cr and P was revealed, suggesting that phosphate groups might act as counter ions of Cr(III), which was also confirmed by the XAFS analysis. Besides, STXM and XAFS analyses showed that Cr(VI) was reduced to Cr(III) in AM fungal structures (arbuscules, intraradical mycelium, etc.) and cell walls in mycorrhizal roots, and complexed possibly with carboxyl groups or histidine analogues. The present work provided evidence of Cr immobilization on fungal surface and in fungal structures in mycorrhizal roots at a cellular level, and thus unraveled the underlying mechanisms by which AM symbiosis immobilize Cr.

  14. Chromium immobilization by extra- and intraradical fungal structures of arbuscular mycorrhizal symbioses

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Songlin [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamycká 129, Prague 6−Suchdol 165 21 (Czech Republic); Zhang, Xin [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Sun, Yuqing; Wu, Zhaoxiang [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Li, Tao [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Hu, Yajun [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125 (China); Lv, Jitao; Li, Gang; Zhang, Zhensong [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhang, Jing; Zheng, Lirong [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Zhen, Xiangjun [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); and others

    2016-10-05

    Highlights: • Cr immobilization in AM symbioses revealed by SEM-EDS, STXM and XAFS. • EPS like particles formed on fungal surface upon Cr(VI) stress. • Cr(VI) was reduced to mainly Cr(III)-phosphate analogues on fungal surface. • Cr can be retained by the intraradical fungal structures in mycorrhizal roots. - Abstract: Arbuscular mycorrhizal (AM) fungi can enhance plant Cr tolerance through immobilizing Cr in mycorrhizal roots. However, the detailed processes and mechanisms are unclear. The present study focused on cellular distribution and speciation of Cr in both extraradical mycelium (ERM) and mycorrhizal roots exposed to Cr(VI) by using field emission scanning electron microscopy equipped with energy dispersive X-ray spectrometer (FE-SEM-EDS), scanning transmission soft X-ray microscopy (STXM) and X-ray absorption fine structure (XAFS) spectroscopy techniques. We found that amounts of particles (possibly extracellular polymeric substances, EPS) were produced on the AM fungal surface upon Cr(VI) stress, which contributed greatly to Cr(VI) reduction and immobilization. With EDS of the surface of AM fungi exposed to various Cr(VI) levels, a positive correlation between Cr and P was revealed, suggesting that phosphate groups might act as counter ions of Cr(III), which was also confirmed by the XAFS analysis. Besides, STXM and XAFS analyses showed that Cr(VI) was reduced to Cr(III) in AM fungal structures (arbuscules, intraradical mycelium, etc.) and cell walls in mycorrhizal roots, and complexed possibly with carboxyl groups or histidine analogues. The present work provided evidence of Cr immobilization on fungal surface and in fungal structures in mycorrhizal roots at a cellular level, and thus unraveled the underlying mechanisms by which AM symbiosis immobilize Cr.

  15. The plasma membrane proteome of Medicago truncatula roots as modified by arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Aloui, Achref; Recorbet, Ghislaine; Lemaître-Guillier, Christelle; Mounier, Arnaud; Balliau, Thierry; Zivy, Michel; Wipf, Daniel; Dumas-Gaudot, Eliane

    2018-01-01

    In arbuscular mycorrhizal (AM) roots, the plasma membrane (PM) of the host plant is involved in all developmental stages of the symbiotic interaction, from initial recognition to intracellular accommodation of intra-radical hyphae and arbuscules. Although the role of the PM as the agent for cellular morphogenesis and nutrient exchange is especially accentuated in endosymbiosis, very little is known regarding the PM protein composition of mycorrhizal roots. To obtain a global overview at the proteome level of the host PM proteins as modified by symbiosis, we performed a comparative protein profiling of PM fractions from Medicago truncatula roots either inoculated or not with the AM fungus Rhizophagus irregularis. PM proteins were isolated from root microsomes using an optimized discontinuous sucrose gradient; their subsequent analysis by liquid chromatography followed by mass spectrometry (MS) identified 674 proteins. Cross-species sequence homology searches combined with MS-based quantification clearly confirmed enrichment in PM-associated proteins and depletion of major microsomal contaminants. Changes in protein amounts between the PM proteomes of mycorrhizal and non-mycorrhizal roots were monitored further by spectral counting. This workflow identified a set of 82 mycorrhiza-responsive proteins that provided insights into the plant PM response to mycorrhizal symbiosis. Among them, the association of one third of the mycorrhiza-responsive proteins with detergent-resistant membranes pointed at partitioning to PM microdomains. The PM-associated proteins responsive to mycorrhization also supported host plant control of sugar uptake to limit fungal colonization, and lipid turnover events in the PM fraction of symbiotic roots. Because of the depletion upon symbiosis of proteins mediating the replacement of phospholipids by phosphorus-free lipids in the plasmalemma, we propose a role of phosphate nutrition in the PM composition of mycorrhizal roots.

  16. Conditions Promoting Mycorrhizal Parasitism Are of Minor Importance for Competitive Interactions in Two Differentially Mycotrophic Species

    Science.gov (United States)

    Friede, Martina; Unger, Stephan; Hellmann, Christine; Beyschlag, Wolfram

    2016-01-01

    Interactions of plants with arbuscular mycorrhizal fungi (AMF) may range along a broad continuum from strong mutualism to parasitism, with mycorrhizal benefits received by the plant being determined by climatic and edaphic conditions affecting the balance between carbon costs vs. nutritional benefits. Thus, environmental conditions promoting either parasitism or mutualism can influence the mycorrhizal growth dependency (MGD) of a plant and in consequence may play an important role in plant-plant interactions. In a multifactorial field experiment we aimed at disentangling the effects of environmental and edaphic conditions, namely the availability of light, phosphorus and nitrogen, and the implications for competitive interactions between Hieracium pilosella and Corynephorus canescens for the outcome of the AMF symbiosis. Both species were planted in single, intraspecific and interspecific combinations using a target-neighbor approach with six treatments distributed along a gradient simulating conditions for the interaction between plants and AMF ranking from mutualistic to parasitic. Across all treatments we found mycorrhizal association of H. pilosella being consistently mutualistic, while pronounced parasitism was observed in C. canescens, indicating that environmental and edaphic conditions did not markedly affect the cost:benefit ratio of the mycorrhizal symbiosis in both species. Competitive interactions between both species were strongly affected by AMF, with the impact of AMF on competition being modulated by colonization. Biomass in both species was lowest when grown in interspecific competition, with colonization being increased in the less mycotrophic C. canescens, while decreased in the obligate mycotrophic H. pilosella. Although parasitism-promoting conditions negatively affected MGD in C. canescens, these effects were small as compared to growth decreases related to increased colonization levels in this species. Thus, the lack of plant control over

  17. Conditions Promoting Mycorrhizal Parasitism are of Minor Importance for Competitive Interactions in Two Differentially Mycotrophic Species

    Directory of Open Access Journals (Sweden)

    Martina Friede

    2016-09-01

    Full Text Available Interactions of plants with arbuscular mycorrhizal fungi (AMF may range along a broad continuum from strong mutualism to parasitism, with mycorrhizal benefits received by the plant being determined by climatic and edaphic conditions affecting the balance between carbon costs vs. nutritional benefits. Thus, environmental conditions promoting either parasitism or mutualism can influence the mycorrhizal growth dependency (MGD of a plant and in consequence may play an important role in plant-plant interactions.In a multifactorial field experiment we aimed at disentangling the effects of environmental and edaphic conditions, namely the availability of light, phosphorus and nitrogen, and the implications for competitive interactions between Hieracium pilosella and Corynephorus canescens for the outcome of the AMF symbiosis. Both species were planted in single, intraspecific and interspecific combinations using a target-neighbor approach with six treatments distributed along a gradient simulating conditions for the interaction between plants and AMF ranking from mutualistic to parasitic.Across all treatments we found mycorrhizal association of H. pilosella being consistently mutualistic, while pronounced parasitism was observed in C. canescens, indicating that environmental and edaphic conditions did not markedly affect the cost:benefit ratio of the mycorrhizal symbiosis in both species. Competitive interactions between both species were strongly affected by AMF, with the impact of AMF on competition being modulated by colonization. Biomass in both species was lowest when grown in interspecific competition, with colonization being increased in the less mycotrophic C. canescens, while decreased in the obligate mycotrophic H. pilosella. Although parasitism-promoting conditions negatively affected MGD in C. canescens, these effects were small as compared to growth decreases related to increased colonization levels in this species. Thus, the lack of plant

  18. Do genetically modified plants impact arbuscular mycorrhizal fungi?

    Science.gov (United States)

    Liu, Wenke

    2010-02-01

    The development and use of genetically modified plants (GMPs), as well as their ecological risks have been a topic of considerable public debate since they were first released in 1996. To date, no consistent conclusions have been drawn dealing with ecological risks on soil microorganisms of GMPs for the present incompatible empirical data. Arbuscular mycorrhizal fungi (AMF), important in regulating aboveground and underground processes in ecosystems, are the most crucial soil microbial community worthy of being monitored in ecological risks assessment of GMPs for their sensitivity to environmental alterations (plant, soil, climatic factor etc.). Based on current data, we suggest that there is a temporal-spatial relevance between expression and rhizosphere secretion of anti-disease and insecticidal proteins (e.g., Bt-Bacillus thuringiensis toxins) in and outer roots, and AMF intraradical and extraradical growth and development. Therefore, taking Bt transgenic plants (BTPs) for example, Bt insecticidal proteins constitutive expression and rhizosphere release during cultivation of BTPs may damage some critical steps of the AMF symbiotic development. More important, these processes of BTPs coincide with the entire life cycle of AMF annually, which may impact the diversity of AMF after long-term cultivation period. It is proposed that interactions between GMPs and AMF should be preferentially studied as an indicator for ecological impacts of GMPs on soil microbial communities. In this review, advances in impacts of GMPs on AMF and the effect mechanisms were summarized, highlighting the possible ecological implications of interactions between GMPs and AMF in soil ecosystems.

  19. The effect of mercury on trees and their mycorrhizal fungi

    Energy Technology Data Exchange (ETDEWEB)

    Jean-Philippe, Sharon R., E-mail: jeanphil@utk.edu [University of Tennessee, Department of Forestry, Wildlife and Fisheries, 274 Ellington Plant Science Building, 2431 Joe Johnson Dr., Knoxville, TN 37996-4563 (United States); Franklin, Jennifer A., E-mail: jafranklin@utk.edu [University of Tennessee, Department of Forestry, Wildlife and Fisheries, 274 Ellington Plant Science Building, 2431 Joe Johnson Dr., Knoxville, TN 37996-4563 (United States); Buckley, David S., E-mail: dbuckley@utk.edu [University of Tennessee, Department of Forestry, Wildlife and Fisheries, 274 Ellington Plant Science Building, 2431 Joe Johnson Dr., Knoxville, TN 37996-4563 (United States); Hughes, Karen, E-mail: khughes@utk.edu [University of Tennessee, Ecology and Evolutionary Biology, 350 Hesler Biology Building and Greenhouse, 1406 Circle Drive, Knoxville, TN 37996-1610 (United States)

    2011-10-15

    The Oak Ridge Reservation, established in 1942, was the designated site for the construction of the atomic bomb. During a 20-year period from 1944 to 1963 radioactive and toxic chemical pollutants, especially mercury compounds were released into the surrounding waterways. Tree diversity and mycorrhizal presence and abundance were analyzed in the mercury-contaminated floodplains of East Fork Poplar Creek Oak Ridge (EFPC) (Tennessee). A subsequent greenhouse study was conducted to assess the phytotoxic effects of different mercuric solutions on Platanus occidentalis (American Sycamore), inoculated with soils from EFPC. Total soil mercury in the field had no effect on tree diversity. Organic species of mercury proved to be more toxic than inorganic species of mercury and soil inoculants from EFPC had no protective effects against Hg toxicity in our greenhouse study. Comparison of the effects of mercury contamination in our field and greenhouse studies was difficult due to uncontrolled factors. - Highlights: > Heavy metals effects on ecosystems may be difficult to pinpoint in the field. > Toxic effects of mercury depend on its chemical form and concentration. > Mycorrhizae have been shown to be increase heavy metal tolerance in host plant. - Though evidence suggests that mercury-contaminated soils may reduce tree and fungal populations, there are tolerant species that may remain and survive following contamination.

  20. Trichoderma harzianum might impact phosphorus transport by arbuscular mycorrhizal fungi.

    Science.gov (United States)

    De Jaeger, Nathalie; de la Providencia, Ivan E; de Boulois, Hervé Dupré; Declerck, Stéphane

    2011-09-01

    Trichoderma sp. is a biocontrol agent active against plant pathogens via mechanisms such as mycoparasitism. Recently, it was demonstrated that Trichoderma harzianum was able to parasitize the mycelium of an arbuscular mycorrhizal (AM) fungus, thus affecting its viability. Here, we question whether this mycoparasitism may reduce the capacity of Glomus sp. to transport phosphorus ((33)P) to its host plant in an in vitro culture system. (33)P was measured in the plant and in the fungal mycelium in the presence/absence of T. harzianum. The viability and metabolic activity of the extraradical mycelium was measured via succinate dehydrogenase and alkaline phosphatase staining. Our study demonstrated an increased uptake of (33)P by the AM fungus in the presence of T. harzianum, possibly related to a stress reaction caused by mycoparasitism. In addition, the disruption of AM extraradical hyphae in the presence of T. harzianum affected the (33)P translocation within the AM fungal mycelium and consequently the transfer of (33)P to the host plant. The effects of T. harzianum on Glomus sp. may thus impact the growth and function of AM fungi and also indirectly plant performance by influencing the source-sink relationship between the two partners of the symbiosis. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  1. Dispersal of arbuscular mycorrhizal fungi and plants during succession

    Science.gov (United States)

    García de León, David; Moora, Mari; Öpik, Maarja; Jairus, Teele; Neuenkamp, Lena; Vasar, Martti; Bueno, C. Guillermo; Gerz, Maret; Davison, John; Zobel, Martin

    2016-11-01

    Arbuscular mycorrhizal (AM) fungi are important root symbionts that enhance plant nutrient uptake and tolerance to pathogens and drought. While the role of plant dispersal in shaping successional vegetation is well studied, there is very little information about the dispersal abilities of AM fungi. We conducted a trap-box experiment in a recently abandoned quarry at 10 different distances from the quarry edge (i.e. the potential propagule source) over eleven months to assess the short term, within-year, arrival of plant and AM fungal assemblages and hence their dispersal abilities. Using DNA based techniques we identified AM fungal taxa and analyzed their phylogenetic diversity. Plant diversity was determined by transporting trap soil to a greenhouse and identifying emerging seedlings. We recorded 30 AM fungal taxa. These contained a high proportion of ruderal AM fungi (30% of taxa, 79% of sequences) but the richness and abundance of AM fungi were not related to the distance from the presumed propagule source. The number of sequences of AM fungi decreased over time. Twenty seven plant species (30% of them ruderal) were recorded from the soil seed traps. Plant diversity decreased with distance from the propagule source and increased over time. Our data show that AM fungi with ruderal traits can be fast colonizers of early successional habitats.

  2. Strigolactones Stimulate Arbuscular Mycorrhizal Fungi by Activating Mitochondria

    Science.gov (United States)

    Besserer, Arnaud; Puech-Pagès, Virginie; Kiefer, Patrick; Gomez-Roldan, Victoria; Jauneau, Alain; Roy, Sébastien; Portais, Jean-Charles; Roux, Christophe; Bécard, Guillaume

    2006-01-01

    The association of arbuscular mycorrhizal (AM) fungi with plant roots is the oldest and ecologically most important symbiotic relationship between higher plants and microorganisms, yet the mechanism by which these fungi detect the presence of a plant host is poorly understood. Previous studies have shown that roots secrete a branching factor (BF) that strongly stimulates branching of hyphae during germination of the spores of AM fungi. In the BF of Lotus, a strigolactone was found to be the active molecule. Strigolactones are known as germination stimulants of the parasitic plants Striga and Orobanche. In this paper, we show that the BF of a monocotyledonous plant, Sorghum, also contains a strigolactone. Strigolactones strongly and rapidly stimulated cell proliferation of the AM fungus Gigaspora rosea at concentrations as low as 10 −13 M. This effect was not found with other sesquiterperne lactones known as germination stimulants of parasitic weeds. Within 1 h of treatment, the density of mitochondria in the fungal cells increased, and their shape and movement changed dramatically. Strigolactones stimulated spore germination of two other phylogenetically distant AM fungi, Glomus intraradices and Gl. claroideum. This was also associated with a rapid increase of mitochondrial density and respiration as shown with Gl. intraradices. We conclude that strigolactones are important rhizospheric plant signals involved in stimulating both the pre-symbiotic growth of AM fungi and the germination of parasitic plants. PMID:16787107

  3. Strigolactones stimulate arbuscular mycorrhizal fungi by activating mitochondria.

    Directory of Open Access Journals (Sweden)

    Arnaud Besserer

    2006-07-01

    Full Text Available The association of arbuscular mycorrhizal (AM fungi with plant roots is the oldest and ecologically most important symbiotic relationship between higher plants and microorganisms, yet the mechanism by which these fungi detect the presence of a plant host is poorly understood. Previous studies have shown that roots secrete a branching factor (BF that strongly stimulates branching of hyphae during germination of the spores of AM fungi. In the BF of Lotus, a strigolactone was found to be the active molecule. Strigolactones are known as germination stimulants of the parasitic plants Striga and Orobanche. In this paper, we show that the BF of a monocotyledonous plant, Sorghum, also contains a strigolactone. Strigolactones strongly and rapidly stimulated cell proliferation of the AM fungus Gigaspora rosea at concentrations as low as 10(-13 M. This effect was not found with other sesquiterperne lactones known as germination stimulants of parasitic weeds. Within 1 h of treatment, the density of mitochondria in the fungal cells increased, and their shape and movement changed dramatically. Strigolactones stimulated spore germination of two other phylogenetically distant AM fungi, Glomus intraradices and Gl. claroideum. This was also associated with a rapid increase of mitochondrial density and respiration as shown with Gl. intraradices. We conclude that strigolactones are important rhizospheric plant signals involved in stimulating both the pre-symbiotic growth of AM fungi and the germination of parasitic plants.

  4. Arbuscular mycorrhizal fungi in arsenic-contaminated areas in Brazil.

    Science.gov (United States)

    Schneider, Jerusa; Stürmer, Sidney Luiz; Guilherme, Luiz Roberto Guimarães; de Souza Moreira, Fatima Maria; Soares, Claudio Roberto Fonsêca de Sousa

    2013-11-15

    Arbuscular mycorrhizal fungi (AMF) are ubiquitous and establish important symbiotic relationships with the majority of the plants, even in soils contaminated with arsenic (As). In order to better understand the ecological relationships of these fungi with excess As in soils and their effects on plants in tropical conditions, occurrence and diversity of AMF were evaluated in areas affected by gold mining activity in Minas Gerais State, Brazil. Soils of four areas with different As concentrations (mg dm(-3)) were sampled: reference Area (10); B1 (subsuperficial layer) (396); barren material (573), and mine waste (1046). Soil sampling was carried out in rainy and dry seasons, including six composite samples per area (n = 24). AMF occurred widespread in all areas, being influenced by As concentrations and sampling periods. A total of 23 species were identified, belonging to the following genus: Acaulospora (10 species), Scutellospora (4 species), Racocetra (3 species), Glomus (4 species), Gigaspora (1 species) and Paraglomus (1 species). The most frequent species occurring in all areas were Paraglomus occultum, Acaulospora morrowiae and Glomus clarum. The predominance of these species indicates their high tolerance to excess As. Although arsenic contamination reduced AMF species richness, presence of host plants tended to counterbalance this reduction. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Compatibility and incompatibility in hyphal anastomosis of arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Candido Barreto de Novais

    Full Text Available ABSTRACT: Arbuscular mycorrhizal fungi (AMF, which live in symbiosis with 80 % of plants, are not able to grow when separated from their hosts. Spore germination is not host-regulated and germling growth is shortly arrested in the absence of host roots. Germling survival chances may be increased by hyphal fusions (anastomoses, which allow access to nutrients flowing in the extraradical mycelium (ERM. Perfect anastomoses, occurring with high frequency among germlings and the ERM of the same isolate, show protoplasm continuity and disappearance of hyphal walls. A low frequency of perfect fusions has been detected among co-specific genetically different isolates, although fungal nuclei have been consistently detected in all perfect fusions, suggesting active nuclear migration. When plants of different taxa establish symbioses with the same AMF species, anastomoses between ERM spreading from single root systems establish a common mycelium, which is an essential element to plant nutrition and communication. The interaction among mycelia produced by different isolates may also lead to pre-fusion incompatibility which hinders anastomosis formation, or to incompatibility after fusion, which separates the hyphal compartments. Results reported here, obtained by analyses of hyphal compatibility/incompatibility in AMF, suggest that anastomosis formation and establishment of protoplasm flow, fundamental to the maintenance of mycelial physiological and genetic continuity, may affect the fitness of these ecologically important biotrophic fungi.

  6. Shoot- and root-borne cytokinin influences arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Cosme, Marco; Ramireddy, Eswarayya; Franken, Philipp; Schmülling, Thomas; Wurst, Susanne

    2016-10-01

    The arbuscular mycorrhizal (AM) symbiosis is functionally important for the nutrition and growth of most terrestrial plants. Nearly all phytohormones are employed by plants to regulate the symbiosis with AM fungi, but the regulatory role of cytokinin (CK) is not well understood. Here, we used transgenic tobacco (Nicotiana tabacum) with a root-specific or constitutive expression of CK-degrading CKX genes and the corresponding wild-type to investigate whether a lowered content of CK in roots or in both roots and shoots influences the interaction with the AM fungus Rhizophagus irregularis. Our data indicates that shoot CK has a positive impact on AM fungal development in roots and on the root transcript level of an AM-responsive phosphate transporter gene (NtPT4). A reduced CK content in roots caused shoot and root growth depression following AM colonization, while neither the uptake of phosphorus or nitrogen nor the root transcript levels of NtPT4 were significantly affected. This suggests that root CK may restrict the C availability from the roots to the fungus thus averting parasitism by AM fungi. Taken together, our study indicates that shoot- and root-borne CK have distinct roles in AM symbiosis. We propose a model illustrating how plants may employ CK to regulate nutrient exchange with the ubiquitous AM fungi.

  7. Signaling events during initiation of arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Schmitz, Alexa M; Harrison, Maria J

    2014-03-01

    Under nutrient-limiting conditions, plants will enter into symbiosis with arbuscular mycorrhizal (AM) fungi for the enhancement of mineral nutrient acquisition from the surrounding soil. AM fungi live in close, intracellular association with plant roots where they transfer phosphate and nitrogen to the plant in exchange for carbon. They are obligate fungi, relying on their host as their only carbon source. Much has been discovered in the last decade concerning the signaling events during initiation of the AM symbiosis, including the identification of signaling molecules generated by both partners. This signaling occurs through symbiosis-specific gene products in the host plant, which are indispensable for normal AM development. At the same time, plants have adapted complex mechanisms for avoiding infection by pathogenic fungi, including an innate immune response to general microbial molecules, such as chitin present in fungal cell walls. How it is that AM fungal colonization is maintained without eliciting a defensive response from the host is still uncertain. In this review, we present a summary of the molecular signals and their elicited responses during initiation of the AM symbiosis, including plant immune responses and their suppression. © 2014 Institute of Botany, Chinese Academy of Sciences.

  8. Fireworks algorithm for mean-VaR/CVaR models

    Science.gov (United States)

    Zhang, Tingting; Liu, Zhifeng

    2017-10-01

    Intelligent algorithms have been widely applied to portfolio optimization problems. In this paper, we introduce a novel intelligent algorithm, named fireworks algorithm, to solve the mean-VaR/CVaR model for the first time. The results show that, compared with the classical genetic algorithm, fireworks algorithm not only improves the optimization accuracy and the optimization speed, but also makes the optimal solution more stable. We repeat our experiments at different confidence levels and different degrees of risk aversion, and the results are robust. It suggests that fireworks algorithm has more advantages than genetic algorithm in solving the portfolio optimization problem, and it is feasible and promising to apply it into this field.

  9. The SAPPHIRE and 50 MT projects at BWXT, Lynchburg, VA

    International Nuclear Information System (INIS)

    Thiele, R.; Horn, B.; Coates, C.W.; Stainback, J.R.

    2001-01-01

    Full text: When the SAPPHIRE project for the down-blending of HEU material of Khazak origin was initiated in 1996 at BWX Technologies (BWXT) formally Babcock and Wilcox in Lynchburg, VA and the Agency was requested to apply its specially designed safeguards measures to the process with a view to provide assurance to the international community that down-blending had actually taken place as stipulated in the USA-Khazak agreement a learning process was initiated from this effort culminating in the current 50 MT downblending process at the same facility with BWXT, the USA Authorities, and the Agency as partners in this technologically advanced enterprise aimed at the downgrading of a substantial quantity of weapons grade material. In the present paper an overview is provided of the road leading to an effective, and mutually agreeable safeguards approach for carrying out verifications in the sensitive environment of a facility devoted to HEU uranium processing. (author)

  10. Calcium uptake by cowpea as influenced by mycorrhizal colonization and water stress

    International Nuclear Information System (INIS)

    Pai, G.; Bagyaraj, D.J.; Padmavathi Ravindra, T.; Prasad, T.G.

    1994-01-01

    The role of vesicular-arbuscular mycorrhizal (VAM) colonization on calcium uptake was studied under different levels of moisture stress. Pots maintained at different moisture levels were given water containing known amount of radioactive calcium. The radioactivity in different parts of the plant was assessed 60 h after giving 45 Ca to the soil. High 45 Ca activity was present in all parts of vesicular-arbuscular mycrrohizal (VAM) plants compared to non-mycorrhizal plants at all levels of moisture stress. (author). 14 refs., 1 tab

  11. Growth and extracellular phosphatase activity of arbuscular mycorrhizal hyphae as influenced by soil organic matter

    DEFF Research Database (Denmark)

    Joner, E.J.; Jakobsen, I.

    1995-01-01

    Two experiments were set up to investigate the influence of soil organic matter on growth of arbuscular mycorrhizal (AM) hyphae and concurrent changes in soil inorganic P, organic P and phosphatase activity. A sandy loam soil was kept for 14 months under two regimes (outdoor where surplus...... additions. In soil with added clover alkaline phosphatase activity increased due to the presence of mycorrhizal hyphae. We suggest that mycorrhizas may influence the exudation of acid phosphatase by roots. Hyphae of G. invermaium did apparently not excrete extracellular phosphatases, but their presence may...

  12. The arbuscular mycorrhizal status of poplar clones selected for phytoremediation of soils contaminated with heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Takacs, T.; Radimszky, L.; Nemeth, T. [Research Inst. for Soil Science and Agricultural Chemistry of the Hungarian Academy of Sciences, Budapest (Hungary)

    2005-04-01

    The aim of this work was to study the colonization of indigenous arbuscular mycorrhizal fungi (AMF) species in fine-roots of poplar clones. Roots of 7 poplar clones were sampled from a 1-year-old trial established at an industrial site strongly polluted with heavy metals at Balatonfuezfoe, Hungary. The poplar clones have shown variable degrees of colonization by AMF, suggesting differential host susceptibility or mycorrhizal dependency. After outplanting the percentage of poplar survival was strongly correlated with the frequency of AMF infection. Two clones that survived at the lowest ratio after outplanting had not been colonized by AMF in contrast to those which survived to a much higher extent. (orig.)

  13. Archetypal Analysis of "Almalek and Albrahmh” from Kalila va Demna

    Directory of Open Access Journals (Sweden)

    Ali Noori

    2016-12-01

    Full Text Available Archetype Theory, has been raised from Carl Gustav Young’s Psychoanalytical School. Young knows mental images and Sediments and Hereditary information which there are in the collective unconscious as Archetype. In other word, archetype is general type of repeated experiences and behaviors of human forefathers which rooted in collective unconscious. the most important Archetypes are "Anima"," Animus", "old wise man", "shadow", "mask", "rebirth" ,and "self" and "individuality". Kalila va Demna is the book which is full of allegorical stories, which because of their mythical aspect, are researchable from Archetypal Analytic criticism. One of this stories which Archetypal color is Dominant in it, is "Almalek and Albrahmh” from 16th chapter of Kalila va Demna. In this study, some archetypes such as "shadow", "Anima", "mask", "old wise man", " self " and "individuality" in the story of "Almalek and Albrahmh" from sixteenth chapter of book, has been analyzed. Since either this tale because of being legendary, and consisting of series of dreams – which have given it mythical, symbolic and interpretable nature – has capacity for archetypal analysis, or archetypal approach has high capacity and power to analyze such narrations. The story was investigated on mentioned view, and it was found that king Heblar which has stricken to a kind of Psychosis, Finds its way into the subconscious through dreams and After a confrontation with his anima, under guidance of old wise meets his self (true self and reach to his individuality and Is rescued from distress. It can be said that the king starts his path of the individual process with a dream.  He, in the bigining of the story, with the help of Iran Dokht and at the end of the story, with the help of minister is released of grief and psychosis.

  14. Development of a continuous energy version of KENO V.a

    International Nuclear Information System (INIS)

    Dunn, M.E.; Bentley, C.L.; Goluoglu, S.; Paschal, L.S.; Dodds, H.L.

    1997-01-01

    KENO V.a is a multigroup Monte Carlo code that solves the Boltzmann transport equation and is used extensively in the nuclear criticality safety community to calculate the effective multiplication factor k eff of systems containing fissile material. Because of the smaller amount of disk storage and CPU time required in calculations, multigroup approaches have been preferred over continuous energy (point) approaches in the past to solve the transport equation. With the advent of high-performance computers, storage and CPU limitations are less restrictive, thereby making continuous energy methods viable for transport calculations. Moreover, continuous energy methods avoid many of the assumptions and approximations inherent in multigroup methods. Because a continuous energy version of KENO V.a does not exist, the objective of the work is to develop a new version of KENO V.a that utilizes continuous energy cross sections. Currently, a point cross-section library, which is based on a raw continuous energy cross-section library such as ENDF/B-V is not available for implementation in KENO V.a; however, point cross-section libraries are available for MCNP, another widely used Monte Carlo transport code. Since MCNP cross sections are based on ENDF data and are readily available, a new version of KENO V.a named PKENO V.a has been developed that performs the random walk using MCNP cross sections. To utilize point cross sections, extensive modifications have been made to KENO V.a. At this point in the research, testing of the code is underway. In particular, PKENO V.a, KENO V.a, and MCNP have been used to model nine critical experiments and one subcritical problem. The results obtained with PKENO V.a are in excellent agreement with MCNP, KENO V.a, and experiments

  15. Growth, cadmium uptake and accumulation of maize (Zea mays L.) under the effects of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Liu, Lingzhi; Gong, Zongqiang; Zhang, Yulong; Li, Peijun

    2014-12-01

    The effects of three arbuscular mycorrhizal fungi isolates on Cd uptake and accumulation by maize (Zea mays L.) were investigated in a planted pot experiment. Plants were inoculated with Glomus intraradices, Glomus constrictum and Glomus mosseae at three different Cd concentrations. The results showed that root colonization increased with Cd addition during a 6-week growth period, however, the fungal density on roots decreased after 9-week growth in the treatments with G. constrictum and G. mosseae isolates. The percentage of mycorrhizal colonization by the three arbuscular mycorrhizal fungi isolates ranged from 22.7 to 72.3%. Arbuscular mycorrhizal fungi inoculations decreased maize biomass especially during the first 6-week growth before Cd addition, and this inhibitory effect was less significant with Cd addition and growth time. Cd concentrations and uptake in maize plants increased with arbuscular mycorrhizal fungi colonization at low Cd concentration (0.02 mM): nonetheless, it decreased at high Cd concentration (0.20 mM) after 6-week growth period. Inoculation with G. constrictum isolates enhanced the root Cd concentrations and uptake, but G. mosseae isolates showed the opposite results at high Cd concentration level after 9 week growth period, as compared to non-mycorrhizal plants. In conclusion, maize plants inoculated with arbuscular mycorrhizal fungi were less sensitive to Cd stress than uninoculated plants. G. constrictum isolates enhanced Cd phytostabilization and G. mosseae isolates reduced Cd uptake in maize (Z. mays L.).

  16. The symbiosis with the arbuscular mycorrhizal fungus Rhizophagus irregularis drives root water transport in flooded tomato plants.

    Science.gov (United States)

    Calvo-Polanco, Monica; Molina, Sonia; Zamarreño, Angel María; García-Mina, Jose María; Aroca, Ricardo

    2014-05-01

    It is known that the presence of arbuscular mycorrhizal fungi within the plant roots enhances the tolerance of the host plant to different environmental stresses, although the positive effect of the fungi in plants under waterlogged conditions has not been well studied. Tolerance of plants to flooding can be achieved through different molecular, physiological and anatomical adaptations, which will affect their water uptake capacity and therefore their root hydraulic properties. Here, we investigated the root hydraulic properties under non-flooded and flooded conditions in non-mycorrhizal tomato plants and plants inoculated with the arbuscular mycorrhizal fungus Rhizophagus irregularis. Only flooded mycorrhizal plants increased their root hydraulic conductivity, and this effect was correlated with a higher expression of the plant aquaporin SlPIP1;7 and the fungal aquaporin GintAQP1. There was also a higher abundance of the PIP2 protein phoshorylated at Ser280 in mycorrhizal flooded plants. The role of plant hormones (ethylene, ABA and IAA) in root hydraulic properties was also taken into consideration, and it was concluded that, in mycorrhizal flooded plants, ethylene has a secondary role regulating root hydraulic conductivity whereas IAA may be the key hormone that allows the enhancement of root hydraulic conductivity in mycorrhizal plants under low oxygen conditions.

  17. Complementarity in nutrient foraging strategies of absorptive fine roots and arbuscular mycorrhizal fungi across 14 coexisting subtropical tree species.

    Science.gov (United States)

    Liu, Bitao; Li, Hongbo; Zhu, Biao; Koide, Roger T; Eissenstat, David M; Guo, Dali

    2015-10-01

    In most cases, both roots and mycorrhizal fungi are needed for plant nutrient foraging. Frequently, the colonization of roots by arbuscular mycorrhizal (AM) fungi seems to be greater in species with thick and sparsely branched roots than in species with thin and densely branched roots. Yet, whether a complementarity exists between roots and mycorrhizal fungi across these two types of root system remains unclear. We measured traits related to nutrient foraging (root morphology, architecture and proliferation, AM colonization and extramatrical hyphal length) across 14 coexisting AM subtropical tree species following root pruning and nutrient addition treatments. After root pruning, species with thinner roots showed more root growth, but lower mycorrhizal colonization, than species with thicker roots. Under multi-nutrient (NPK) addition, root growth increased, but mycorrhizal colonization decreased significantly, whereas no significant changes were found under nitrogen or phosphate additions. Moreover, root length proliferation was mainly achieved by altering root architecture, but not root morphology. Thin-root species seem to forage nutrients mainly via roots, whereas thick-root species rely more on mycorrhizal fungi. In addition, the reliance on mycorrhizal fungi was reduced by nutrient additions across all species. These findings highlight complementary strategies for nutrient foraging across coexisting species with contrasting root traits. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  18. Dynamics of arbuscular mycorrhizal fungal community structure and functioning along a nitrogen enrichment gradient in an alpine meadow ecosystem.

    Science.gov (United States)

    Jiang, Shengjing; Liu, Yongjun; Luo, Jiajia; Qin, Mingsen; Johnson, Nancy Collins; Öpik, Maarja; Vasar, Martti; Chai, Yuxing; Zhou, Xiaolong; Mao, Lin; Du, Guozhen; An, Lizhe; Feng, Huyuan

    2018-03-30

    Nitrogen (N) availability is increasing dramatically in many ecosystems, but the influence of elevated N on the functioning of arbuscular mycorrhizal (AM) fungi in natural ecosystems is not well understood. We measured AM fungal community structure and mycorrhizal function simultaneously across an experimental N addition gradient in an alpine meadow that is limited by N but not by phosphorus (P). AM fungal communities at both whole-plant-community (mixed roots) and single-plant-species (Elymus nutans roots) scales were described using pyro-sequencing, and the mycorrhizal functioning was quantified using a mycorrhizal-suppression treatment in the field (whole-plant-community scale) and a glasshouse inoculation experiment (single-plant-species scale). Nitrogen enrichment progressively reduced AM fungal abundance, changed AM fungal community composition, and shifted mycorrhizal functioning towards parasitism at both whole-plant-community and E. nutans scales. N-induced shifts in AM fungal community composition were tightly linked to soil N availability and/or plant species richness, whereas the shifts in mycorrhizal function were associated with the communities of specific AM fungal lineages. The observed changes in both AM fungal community structure and functioning across an N enrichment gradient highlight that N enrichment of ecosystems that are not P-limited can induce parasitic mycorrhizal functioning and influence plant community structure and ecosystem sustainability. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  19. Effects of cadmium and mycorrhizal fungi on growth, fitness, and cadmium accumulation in flax (Linum usitatissimum; Linaceae).

    Science.gov (United States)

    Hancock, Laura M S; Ernst, Charlotte L; Charneskie, Rebecca; Ruane, Lauren G

    2012-09-01

    Agricultural soils have become contaminated with a variety of heavy metals, including cadmium. The degree to which soil contaminants affect plants may depend on symbiotic relationships between plant roots and soil microorganisms. We examined (1) whether mycorrhizal fungi counteract the potentially negative effects of cadmium on the growth and fitness of flax (Linum usitatissimum) and (2) whether mycorrhizal fungi affect the accumulation of cadmium within plant parts. Two flax cultivars (Linott and Omega) were grown in three soil cadmium environments (0, 5, and 15 ppm). Within each cadmium environment, plants were grown in either the presence or absence of mycorrhizal fungi. Upon senescence, we measured growth and fitness and quantified the concentration of cadmium within plants. Soil cadmium significantly decreased plant fitness, but did not affect plant growth. Mycorrhizal fungi, which were able to colonize roots of plants growing in all cadmium levels, significantly increased plant growth and fitness. Although mycorrhizal fungi counteracted the negative effects of cadmium on fruit and seed production, they also enhanced the concentration of cadmium within roots, fruits, and seeds. The degree to which soil cadmium affects plant fitness and the accumulation of cadmium within plants depended on the ability of plants to form symbiotic relationships with mycorrhizal fungi. The use of mycorrhizal fungi in contaminated agricultural soils may offset the negative effects of metals on the quantity of seeds produced, but exacerbate the accumulation of these metals in our food supply.

  20. Genotypic variation in the response of chickpea to arbuscular mycorrhizal fungi and non-mycorrhizal fungal endophytes.

    Science.gov (United States)

    Bazghaleh, Navid; Hamel, Chantal; Gan, Yantai; Tar'an, Bunyamin; Knight, Joan Diane

    2018-04-01

    Plant roots host symbiotic arbuscular mycorrhizal (AM) fungi and other fungal endophytes that can impact plant growth and health. The impact of microbial interactions in roots may depend on the genetic properties of the host plant and its interactions with root-associated fungi. We conducted a controlled condition experiment to investigate the effect of several chickpea (Cicer arietinum L.) genotypes on the efficiency of the symbiosis with AM fungi and non-AM fungal endophytes. Whereas the AM symbiosis increased the biomass of most of the chickpea cultivars, inoculation with non-AM fungal endophytes had a neutral effect. The chickpea cultivars responded differently to co-inoculation with AM fungi and non-AM fungal endophytes. Co-inoculation had additive effects on the biomass of some cultivars (CDC Corrine, CDC Anna, and CDC Cory), but non-AM fungal endophytes reduced the positive effect of AM fungi on Amit and CDC Vanguard. This study demonstrated that the response of plant genotypes to an AM symbiosis can be modified by the simultaneous colonization of the roots by non-AM fungal endophytes. Intraspecific variations in the response of chickpea to AM fungi and non-AM fungal endophytes indicate that the selection of suitable genotypes may improve the ability of crop plants to take advantage of soil ecosystem services.

  1. The role of plant mycorrhizal type and status in modulating the relationship between plant and arbuscular mycorrhizal fungal communities.

    Science.gov (United States)

    Neuenkamp, Lena; Moora, Mari; Öpik, Maarja; Davison, John; Gerz, Maret; Männistö, Minna; Jairus, Teele; Vasar, Martti; Zobel, Martin

    2018-01-25

    Interactions between communities of plants and arbuscular mycorrhizal (AM) fungi shape fundamental ecosystem properties. Experimental evidence suggests that compositional changes in plant and AM fungal communities should be correlated, but empirical data from natural ecosystems are scarce. We investigated the dynamics of covariation between plant and AM fungal communities during three stages of grassland succession, and the biotic and abiotic factors shaping these dynamics. Plant communities were characterised using vegetation surveys. AM fungal communities were characterised by 454-sequencing of the small subunit rRNA gene and identification against the AM fungal reference database MaarjAM. AM fungal abundance was estimated using neutral-lipid fatty acids (NLFAs). Multivariate correlation analysis (Procrustes) revealed a significant relationship between plant and AM fungal community composition. The strength of plant-AM fungal correlation weakened during succession following cessation of grassland management, reflecting changes in the proportion of plants exhibiting different AM status. Plant-AM fungal correlation was strong when the abundance of obligate AM plants was high, and declined as the proportion of facultative AM plants increased. We conclude that the extent to which plants rely on AM symbiosis can determine how tightly communities of plants and AM fungi are interlinked, regulating community assembly of both symbiotic partners. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  2. Long-term agricultural fertilization alters arbuscular mycorrhizal fungal community composition and barley (Hordeum vulgare) mycorrhizal carbon and phosphorus exchange.

    Science.gov (United States)

    Williams, Alwyn; Manoharan, Lokeshwaran; Rosenstock, Nicholas P; Olsson, Pål Axel; Hedlund, Katarina

    2017-01-01

    Agricultural fertilization significantly affects arbuscular mycorrhizal fungal (AMF) community composition. However, the functional implications of community shifts are unknown, limiting understanding of the role of AMF in agriculture. We assessed AMF community composition at four sites managed under the same nitrogen (N) and phosphorus (P) fertilizer regimes for 55 yr. We also established a glasshouse experiment with the same soils to investigate AMF-barley (Hordeum vulgare) nutrient exchange, using carbon ( 13 C) and 33 P isotopic labelling. N fertilization affected AMF community composition, reducing diversity; P had no effect. In the glasshouse, AMF contribution to plant P declined with P fertilization, but was unaffected by N. Barley C allocation to AMF also declined with P fertilization. As N fertilization increased, C allocation to AMF per unit of P exchanged increased. This occurred with and without P fertilization, and was concomitant with reduced barley biomass. AMF community composition showed no relationship with glasshouse experiment results. The results indicate that plants can reduce C allocation to AMF in response to P fertilization. Under N fertilization, plants allocate an increasing amount of C to AMF and receive relatively less P. This suggests an alteration in the terms of P-C exchange under N fertilization regardless of soil P status. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  3. 76 FR 38302 - Safety Zone; Cape Charles Fireworks, Cape Charles Harbor, Cape Charles, VA

    Science.gov (United States)

    2011-06-30

    ... the Town of Cape Charles will sponsor a fireworks display on the shoreline of the navigable waters of...-AA00 Safety Zone; Cape Charles Fireworks, Cape Charles Harbor, Cape Charles, VA AGENCY: Coast Guard... navigable waters of Cape Charles City Harbor in Cape Charles, VA in support of the Fourth of July Fireworks...

  4. 76 FR 27970 - Safety Zone; Cape Charles Fireworks, Cape Charles Harbor, Cape Charles, VA.

    Science.gov (United States)

    2011-05-13

    ... Charles will sponsor a fireworks display on the shoreline of the navigable waters of Cape Charles City...[deg]01'30'' W (NAD 1983). This safety zone will be established in the vicinity of Cape Charles, VA...-AA00 Safety Zone; Cape Charles Fireworks, Cape Charles Harbor, Cape Charles, VA. AGENCY: Coast Guard...

  5. 77 FR 29929 - Safety Zone; Town of Cape Charles Fireworks, Cape Charles Harbor, Cape Charles, VA

    Science.gov (United States)

    2012-05-21

    ... section of this notice. Basis and Purpose On July 4, 2012 the Town of Cape Charles will sponsor a...-AA00 Safety Zone; Town of Cape Charles Fireworks, Cape Charles Harbor, Cape Charles, VA AGENCY: Coast... temporary safety zone on the waters of Cape Charles City Harbor in Cape Charles, VA in support of the Fourth...

  6. 77 FR 60746 - Proposed Information Collection (VA/DOD Joint Disability Evaluation Board Claim) Activity...

    Science.gov (United States)

    2012-10-04

    ... burden of the collection of information on respondents, including through the use of automated collection techniques or the use of other forms of information technology. Title: VA/DOD Joint Disability Evaluation... War on Terror Heroes, VA and the Department of Defense (DOD) have agreed to develop a joint process in...

  7. 76 FR 44288 - Establishment of Class E Airspace; New Market, VA

    Science.gov (United States)

    2011-07-25

    ...-380; Airspace Docket No. 11-AEA-12] Establishment of Class E Airspace; New Market, VA AGENCY: Federal... proposes to establish Class E Airspace at New Market, VA, to accommodate the additional airspace needed for the Standard Instrument Approach Procedures developed for New Market Airport. This action would...

  8. 38 CFR 1.9 - Description, use, and display of VA seal and flag.

    Science.gov (United States)

    2010-07-01

    ... stars represent the five branches of military service. The crossed flags represent our nation's history... employees. (D) Official VA signs. (E) Official publications or graphics issued by and attributed to VA, or...) Souvenir or novelty items. (iii) Toys or commercial gifts or premiums. (iv) Letterhead design, except on...

  9. 78 FR 31840 - Safety Zone; USO Patriotic Festival Air Show, Atlantic Ocean; Virginia Beach, VA

    Science.gov (United States)

    2013-05-28

    ...-AA00 Safety Zone; USO Patriotic Festival Air Show, Atlantic Ocean; Virginia Beach, VA AGENCY: Coast... provide for the safety of life on navigable waters during the USO Patriotic Festival Air Show. This action... Patriotic Festival Air Show, Atlantic Ocean; Virginia Beach, VA. (a) Regulated Area. The following area is a...

  10. 77 FR 74279 - Agency Information Collection (VA/DOD Joint Disability Evaluation Board Claim): Activity under...

    Science.gov (United States)

    2012-12-13

    ... Joint Disability Evaluation Board Claim): Activity under OMB Review AGENCY: Veterans Benefits... . Please refer to ``OMB Control No. 2900-0704.'' SUPPLEMENTARY INFORMATION: Title: VA/DOD Joint Disability Evaluation Board Claim, VA Form 21- 0819. OMB Control Number: 2900-0704. Type of Review: Extension of a...

  11. 75 FR 25321 - Agency Information Collection (VA National Rehabilitation Special Events, Event Registration...

    Science.gov (United States)

    2010-05-07

    ... Winter Sports Clinic Application, VA Form 0924a series. b. National Veterans Wheelchair Games Application.... National Veterans TEE Tournament Application, VA Form 0927a series. e. National Veterans Summer Sports... Form 0929a series. Type of Review: Existing collection in use without an OMB control number. Abstract...

  12. 48 CFR 853.236-70 - VA Form 10-6298, Architect-Engineer Fee Proposal.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false VA Form 10-6298, Architect-Engineer Fee Proposal. 853.236-70 Section 853.236-70 Federal Acquisition Regulations System DEPARTMENT OF...-Engineer Fee Proposal. VA Form 10-6298, Architect-Engineer Fee Proposal, shall be used as prescribed in 836...

  13. A Stochastic Dominance Approach to the Basel III Dilemma: Expected Shortfall or VaR?

    NARCIS (Netherlands)

    C-L. Chang (Chia-Lin); J.A. Jiménez-Martín (Juan-Ángel); E. Maasoumi (Esfandiar); M.J. McAleer (Michael); T. Pérez-Amaral (Teodosio)

    2015-01-01

    markdownabstract__Abstract__ The Basel Committee on Banking Supervision (BCBS) (2013) recently proposed shifting the quantitative risk metrics system from Value-at-Risk (VaR) to Expected Shortfall (ES). The BCBS (2013) noted that “a number of weaknesses have been identified with using VaR for

  14. 38 CFR 3.2130 - Will VA accept a signature by mark or thumbprint?

    Science.gov (United States)

    2010-07-01

    ... signature by mark or thumbprint? 3.2130 Section 3.2130 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF... of This Title General § 3.2130 Will VA accept a signature by mark or thumbprint? VA will accept signatures by mark or thumbprint if: (a) They are witnessed by two people who sign their names and give their...

  15. Conformational determination of [Leu]enkephalin based on theoretical and experimental VA and VCD spectral analyses

    DEFF Research Database (Denmark)

    Abdali, Salim; Jalkanen, Karl J.; Cao, X.

    2004-01-01

    Conformational determination of [Leu]enkephalin in DMSO-d6 is carried out using VA and VCD spectral analyses. Conformational energies, vibrational frequencies and VA and VCD intensities are calculated using DFT at B3LYP/6-31G* level of theory. Comparison between the measured spectra...

  16. 38 CFR 74.26 - What types of business information will VA collect?

    Science.gov (United States)

    2010-07-01

    ... VETERANS AFFAIRS (CONTINUED) VETERANS SMALL BUSINESS REGULATIONS Records Management § 74.26 What types of business information will VA collect? VA will examine a variety of business records. See § 74.12, “What is... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false What types of business...

  17. 77 FR 21158 - VA Directive 0005 on Scientific Integrity: Availability for Review and Comment

    Science.gov (United States)

    2012-04-09

    ... Draft VA Directive 0005 on Scientific Integrity: [square] Fosters a culture of transparency, integrity, and ethical behavior in the development and application of scientific and technological findings in VA... information from inappropriate political or commercial influence; [square] Ensures that selection and...

  18. 48 CFR 803.7000 - Display of the VA Hotline poster.

    Science.gov (United States)

    2010-10-01

    ... poster. 803.7000 Section 803.7000 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS... Improper Business Practices 803.7000 Display of the VA Hotline poster. (a) Under the circumstances described in paragraph (b) of this section, a contractor must display prominently a VA Hotline poster...

  19. 76 FR 27381 - Proposed Information Collection (Notice of Waiver of VA Compensation or Pension To Receive...

    Science.gov (United States)

    2011-05-11

    ... waive VA benefits for the number of days equal to the number of days in which they received training pay... of Waiver of VA Compensation or Pension To Receive Military Pay and Allowances) Activity; Comment... currently approved collection, and allow 60 days for public comment in response to the notice. This notice...

  20. 78 FR 66265 - Drawbridge Operation Regulation; Elizabeth River, Eastern Branch, Norfolk, VA

    Science.gov (United States)

    2013-11-05

    ... Operation Regulation; Elizabeth River, Eastern Branch, Norfolk, VA AGENCY: Coast Guard, DHS. ACTION: Notice... Elizabeth River Eastern Branch, mile 1.1, at Norfolk, VA. This deviation is necessary to facilitate... maintenance. The Norfolk Southern 5 railroad Bridge, at mile 1.1, across the Elizabeth River (Eastern Branch...

  1. 78 FR 55777 - Proposed Information Collection (VA, National Veterans Sports Programs and Special Events, Event...

    Science.gov (United States)

    2013-09-11

    ... techniques or the use of other forms of information technology. Titles: a. National Disabled Veterans Winter... Form 0928h. m. Surfing Personnel Application, VA Form 0928i. n. Venue Personnel Application, VA Form... Creative Arts Festival, National Veterans TEE Tournament, National Disabled Veterans Winter Sports Clinic...

  2. Comparing VA and private sector healthcare costs for end-stage renal disease.

    Science.gov (United States)

    Hynes, Denise M; Stroupe, Kevin T; Fischer, Michael J; Reda, Domenic J; Manning, Willard; Browning, Margaret M; Huo, Zhiping; Saban, Karen; Kaufman, James S

    2012-02-01

    Healthcare for end-stage renal disease (ESRD) is intensive, expensive, and provided in both the public and private sector. Using a societal perspective, we examined healthcare costs and health outcomes for Department of Veterans Affairs (VA) ESRD patients comparing those who received hemodialysis care at VA versus private sector facilities. Dialysis patients were recruited from 8 VA medical centers from 2001 through 2003 and followed for 12 months in a prospective cohort study. Patient demographics, clinical characteristics, quality of life, healthcare use, and cost data were collected. Healthcare data included utilization (VA), claims (Medicare), and patient self-report. Costs included VA calculated costs, Medicare dialysis facility reports and reimbursement rates, and patient self-report. Multivariable regression was used to compare costs between patients receiving dialysis at VA versus private sector facilities. The cohort comprised 334 patients: 170 patients in the VA dialysis group and 164 patients in the private sector group. The VA dialysis group had more comorbidities at baseline, outpatient and emergency visits, prescriptions, and longer hospital stays; they also had more conservative anemia management and lower baseline urea reduction ratio (67% vs. 72%; Pprivate sector dialysis group (Pprivate sector settings is critical in informing health policy options for patients with complex chronic illnesses such as ESRD.

  3. 75 FR 34934 - Safety Zone; Fireworks for the Virginia Lake Festival, Buggs Island Lake, Clarksville, VA

    Science.gov (United States)

    2010-06-21

    ...-AA00 Safety Zone; Fireworks for the Virginia Lake Festival, Buggs Island Lake, Clarksville, VA AGENCY... Fireworks for the Virginia Lake Festival event. This action is intended to restrict vessel traffic movement... Virginia Lake Festival, Buggs Island Lake, Clarksville, VA (a) Regulated Area. The following area is a...

  4. MODEL NON LINIER GARCH (NGARCH UNTUK MENGESTIMASI NILAI VALUE at RISK (VaR PADA IHSG

    Directory of Open Access Journals (Sweden)

    I KOMANG TRY BAYU MAHENDRA

    2015-06-01

    Full Text Available In investment, risk measurement is important. One of risk measure is Value at Risk (VaR. There are many methods that can be used to estimate risk based on VaR framework. One of them Non Linier GARCH (NGARCH model. In this research, determination of VaR used NGARCH model. NGARCH model allowed for asymetric behaviour in the volatility such that “good news” or positive return and “bad news” or negative return. Based on calculations of VaR, the higher of the confidence level and the longer the investment period, the risk was greater. Determination of VaR using NGARCH model was less than GARCH model.

  5. Empirical analysis on future-cash arbitrage risk with portfolio VaR

    Science.gov (United States)

    Chen, Rongda; Li, Cong; Wang, Weijin; Wang, Ze

    2014-03-01

    This paper constructs the positive arbitrage position by alternating the spot index with Chinese Exchange Traded Fund (ETF) portfolio and estimating the arbitrage-free interval of futures with the latest trade data. Then, an improved Delta-normal method was used, which replaces the simple linear correlation coefficient with tail dependence correlation coefficient, to measure VaR (Value-at-risk) of the arbitrage position. Analysis of VaR implies that the risk of future-cash arbitrage is less than that of investing completely in either futures or spot market. Then according to the compositional VaR and the marginal VaR, we should increase the futures position and decrease the spot position appropriately to minimize the VaR, which can minimize risk subject to certain revenues.

  6. Identifying Homelessness among Veterans Using VA Administrative Data: Opportunities to Expand Detection Criteria

    Science.gov (United States)

    Peterson, Rachel; Gundlapalli, Adi V.; Metraux, Stephen; Carter, Marjorie E.; Palmer, Miland; Redd, Andrew; Samore, Matthew H.; Fargo, Jamison D.

    2015-01-01

    Researchers at the U.S. Department of Veterans Affairs (VA) have used administrative criteria to identify homelessness among U.S. Veterans. Our objective was to explore the use of these codes in VA health care facilities. We examined VA health records (2002-2012) of Veterans recently separated from the military and identified as homeless using VA conventional identification criteria (ICD-9-CM code V60.0, VA specific codes for homeless services), plus closely allied V60 codes indicating housing instability. Logistic regression analyses examined differences between Veterans who received these codes. Health care services and co-morbidities were analyzed in the 90 days post-identification of homelessness. VA conventional criteria identified 21,021 homeless Veterans from Operations Enduring Freedom, Iraqi Freedom, and New Dawn (rate 2.5%). Adding allied V60 codes increased that to 31,260 (rate 3.3%). While certain demographic differences were noted, Veterans identified as homeless using conventional or allied codes were similar with regards to utilization of homeless, mental health, and substance abuse services, as well as co-morbidities. Differences were noted in the pattern of usage of homelessness-related diagnostic codes in VA facilities nation-wide. Creating an official VA case definition for homelessness, which would include additional ICD-9-CM and other administrative codes for VA homeless services, would likely allow improved identification of homeless and at-risk Veterans. This also presents an opportunity for encouraging uniformity in applying these codes in VA facilities nationwide as well as in other large health care organizations. PMID:26172386

  7. Identifying Homelessness among Veterans Using VA Administrative Data: Opportunities to Expand Detection Criteria.

    Directory of Open Access Journals (Sweden)

    Rachel Peterson

    Full Text Available Researchers at the U.S. Department of Veterans Affairs (VA have used administrative criteria to identify homelessness among U.S. Veterans. Our objective was to explore the use of these codes in VA health care facilities. We examined VA health records (2002-2012 of Veterans recently separated from the military and identified as homeless using VA conventional identification criteria (ICD-9-CM code V60.0, VA specific codes for homeless services, plus closely allied V60 codes indicating housing instability. Logistic regression analyses examined differences between Veterans who received these codes. Health care services and co-morbidities were analyzed in the 90 days post-identification of homelessness. VA conventional criteria identified 21,021 homeless Veterans from Operations Enduring Freedom, Iraqi Freedom, and New Dawn (rate 2.5%. Adding allied V60 codes increased that to 31,260 (rate 3.3%. While certain demographic differences were noted, Veterans identified as homeless using conventional or allied codes were similar with regards to utilization of homeless, mental health, and substance abuse services, as well as co-morbidities. Differences were noted in the pattern of usage of homelessness-related diagnostic codes in VA facilities nation-wide. Creating an official VA case definition for homelessness, which would include additional ICD-9-CM and other administrative codes for VA homeless services, would likely allow improved identification of homeless and at-risk Veterans. This also presents an opportunity for encouraging uniformity in applying these codes in VA facilities nationwide as well as in other large health care organizations.

  8. Sheared-root inocula of vesicular-arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Sylvia, D M; Jarstfer, A G

    1992-01-01

    For efficient handling, vesicular-arbuscular mycorrhizal fungi should be processed into small and uniform inocula; however, processing can reduce the inoculum density. In this article we describe the preparation and use of sheared-root inocula of Glomus spp. in which inoculum densities were increased during processing. Our objectives were to determine inoculum viability and density after shearing and to ascertain if the sheared inocula could be pelletized or used with a gel carrier. Root samples were harvested from aeroponic cultures, blotted dry, cut into 1-cm lengths, and sheared in a food processor for up to 80 s. After shearing, the inoculum was washed over sieves, and the propagule density in each fraction was determined. Sheared inocula were also encapsulated in carrageenan or used in a gel carrier. Shearing aeroponically produced root inocula reduced particle size. Propagule density increased with decreasing size fraction down to a size of 63 mum, after which propagule density decreased. The weighted-average propagule density of the inoculum was 135,380 propagules g (dry weight) of sheared root material. Sheared roots were encapsulated successfully in carrageenan, and the gel served as an effective carrier. Aeroponic root inoculum was stored dry at 4 degrees C for 23 months without significant reduction in propagule density; however, this material was not appropriate for shearing. Moist roots, useful for shearing, began to lose propagule density after 1 month of storage. Shearing proved to be an excellent method to prepare viable root inocula of small and uniform size, allowing for more efficient and effective use of limited inoculum supplies.

  9. Development of soil quality metrics using mycorrhizal fungi

    Energy Technology Data Exchange (ETDEWEB)

    Baar, J.

    2010-07-01

    Based on the Treaty on Biological Diversity of Rio de Janeiro in 1992 for maintaining and increasing biodiversity, several countries have started programmes monitoring soil quality and the above- and below ground biodiversity. Within the European Union, policy makers are working on legislation for soil protection and management. Therefore, indicators are needed to monitor the status of the soils and these indicators reflecting the soil quality, can be integrated in working standards or soil quality metrics. Soil micro-organisms, particularly arbuscular mycorrhizal fungi (AMF), are indicative of soil changes. These soil fungi live in symbiosis with the great majority of plants and are sensitive to changes in the physico-chemical conditions of the soil. The aim of this study was to investigate whether AMF are reliable and sensitive indicators for disturbances in the soils and can be used for the development of soil quality metrics. Also, it was studied whether soil quality metrics based on AMF meet requirements to applicability by users and policy makers. Ecological criterions were set for the development of soil quality metrics for different soils. Multiple root samples containing AMF from various locations in The Netherlands were analyzed. The results of the analyses were related to the defined criterions. This resulted in two soil quality metrics, one for sandy soils and a second one for clay soils, with six different categories ranging from very bad to very good. These soil quality metrics meet the majority of requirements for applicability and are potentially useful for the development of legislations for the protection of soil quality. (Author) 23 refs.

  10. Pre-inoculation by an arbuscular mycorrhizal fungus enhances male reproductive output of Cucurbita foetidissima

    Science.gov (United States)

    Rosemary L. Pendleton

    2000-01-01

    Male and female reproductive output of Cucurbita foetidissima, a gynodioecious native perennial, was examined in a 2-yr greenhouse/outplanting study. Plants were divided into three treatment groups: (1) a lowphosphorus (P) soil mix control; (2) a low-P soil mix with the addition of mycorrhizal inoculum (Glomus intraradices); and (3) a high-P soil mix. Plants were...

  11. Different effect of mycorrhizal inoculation in direct and indirect reclamation of spoil banks

    Czech Academy of Sciences Publication Activity Database

    Rydlová, Jana; Püschel, David; Vosátka, Miroslav; Charvátová, K.

    2008-01-01

    Roč. 82, č. 1 (2008), s. 15-20 ISSN 1613-9216 R&D Projects: GA MŠk 1M0571 Institutional research plan: CEZ:AV0Z60050516 Keywords : arbuscular mycorrhizal fungi * inoculum * reclamation Subject RIV: EF - Botanics Impact factor: 0.482, year: 2008

  12. BIOMETRIC PARAMETERS OF FIELD GROWN SESAME INFLUENCED BY ARBUSCULAR MYCORRHIZAL INOCULATION, ROCK PHOSPHATE FERTILIZATION AND IRRIGATION

    Directory of Open Access Journals (Sweden)

    V.S. Harikumar

    2017-08-01

    Full Text Available The aim of the study was to assess the effect of inoculation with arbuscular mycorrhizal fungi (AMF and rock phosphate (RP fertilization on biometric parameters and mycorrhizal colonization of field grown sesame under rainfed and irrigated conditions. Inoculation of AMF Funneliformis dimorphicus improved the biometric parameters of the crop such as leaf area (LA, leaf area index (LAI, specific leaf weight (SLW, net assimilation rate (NAR, oil index (OI as well as mycorrhizal colonization (%F in roots. Mycorrhizal inoculation however, did not give any positive response on harvest index (HI. LA, LAI and OI and %F showed a general increment in treatments of no added P (P0, while the other parameters such as SLW and NAR were improved by the application of RP at half the recommended dose (P50. HI did not respond to RP fertilization. Most of the parameters (LA, LAI, NAR, %F showed higher values under rainfed condition than irrigated condition whereas, SLW, HI and OI improved significantly under irrigated condition. Results indicated that the inoculation of AMF to field grown sesame can compensate for 50% of the recommended P fertilizer under a need based irrigation schedule, without affecting the biometric parameters.

  13. Transcriptome analysis of arbuscular mycorrhizal roots during development of the prepenetration apparatus

    NARCIS (Netherlands)

    Siciliano, V.; Genre, A.; Balestrini, R.; Cappellazzo, G.; Wit, de P.J.G.M.; Bonfante, P.

    2007-01-01

    Information on changes in the plant transcriptome during early interaction with arbuscular mycorrhizal (AM) fungi is still limited since infections are usually not synchronized and plant markers for early stages of colonization are not yet available. A prepenetration apparatus (PPA), organized in

  14. Predicting community and ecosystem outcomes of mycorrhizal responses to global change.

    NARCIS (Netherlands)

    Johnson, N.C.; Angelard, C.; Sanders, I.R.; Kiers, E.T.

    2013-01-01

    Mycorrhizal symbioses link the biosphere with the lithosphere by mediating nutrient cycles and energy flow though terrestrial ecosystems. A more mechanistic understanding of these plant-fungal associations may help ameliorate anthropogenic changes to C and N cycles and biotic communities. We explore

  15. Taking mycocentrism seriously: mycorrhizal fungal and plant responses to elevated CO2

    NARCIS (Netherlands)

    Alberton, O.; Kuyper, T.W.; Gorissen, A.

    2005-01-01

    The aim here was to separately assess mycorrhizal fungal and plant responses under elevated atmospheric CO2, and to test a mycocentric model that assumes that increased carbon availability to the fungus will not automatically feed back to enhanced plant growth performance. Meta-analyses were applied

  16. Simulated nitrogen deposition affects community structure of arbuscular mycorrhizal fungi in northern hardwood forests

    Science.gov (United States)

    Linda T.A. Van Diepen; Erik Lilleskov; Kurt S. Pregitzer

    2011-01-01

    Our previous investigation found elevated nitrogen deposition caused declines in abundance of arbuscular mycorrhizal fungi (AMF) associated with forest trees, but little is known about how nitrogen affects the AMF community composition and structure within forest ecosystems. We hypothesized that N deposition would lead to significant changes in the AMF community...

  17. Arbuscular mycorrhizal fungal species differ in their effect on nutrient leaching

    NARCIS (Netherlands)

    Köhl, Luise; van der Heijden, Marcel G A

    2016-01-01

    Arbuscular mycorrhizal (AM) fungi have been shown to play a crucial role in nutrient cycling and can reduce nutrient losses after rain induced leaching events. It is still unclear whether nutrient leaching losses vary depending on the AM fungal taxa that are present in soil. Using experimental

  18. Duration and intensity of shade differentially affects mycorrhizal growth- and phosphorus uptake responses of Medicago truncatula

    Czech Academy of Sciences Publication Activity Database

    Konvalinková, Tereza; Püschel, David; Janoušková, Martina; Gryndler, Milan; Jansa, Jan

    2015-01-01

    Roč. 6, FEB 13 (2015), s. 1-11 ISSN 1664-462X R&D Projects: GA MŠk(CZ) LK11224 Institutional support: RVO:61388971 Keywords : arbuscular mycorrhizal symbiosis * light intensity * shading duration Subject RIV: EE - Microbiology, Virology Impact factor: 4.495, year: 2015

  19. Influence of cadmium and mycorrhizal fungi on the fatty acid profile of flax (Linum usitatissimum) seeds.

    Science.gov (United States)

    Kaplan, Matthew E; Simmons, Ellen R; Hawkins, Jack C; Ruane, Lauren G; Carney, Jeffrey M

    2015-09-01

    The soil environment can affect not only the quantity of crops produced but also their nutritional quality. We examined the combined effects of below-ground cadmium (0, 5, and 15 ppm) and mycorrhizal fungi (presence and absence) on the concentration of five major fatty acids within flax seeds (Linum usitatissimum). Plants grown with mycorrhizal fungi produced seeds that contained higher concentrations of unsaturated (18:1, 18:2 and 18:3), but not saturated (16:0 and 18:0) fatty acids. The effects of mycorrhizal fungi on the concentration of unsaturated fatty acids in seeds were most pronounced when plant roots were exposed to 15 ppm Cd (i.e. the concentrations of 18:1, 18:2 and 18:3 increased by 169%, 370% and 150%, respectively). The pronounced effects of mycorrhizal fungi on the concentration of unsaturated fatty acids at 15 ppm Cd may have been due to the presence of elevated levels of Cd within seeds. Our results suggest that, once the concentration of cadmium within seeds reaches a certain threshold, this heavy metal may improve the efficiency of enzymes that convert saturated fatty acids to unsaturated fatty acids. © 2014 Society of Chemical Industry.

  20. Arbuscular mycorrhizal fungi differentially affect the response to high zinc concentrations of two registered poplar clones

    International Nuclear Information System (INIS)

    Lingua, Guido; Franchin, Cinzia; Todeschini, Valeria; Castiglione, Stefano; Biondi, Stefania; Burlando, Bruno; Parravicini, Valerio; Torrigiani, Patrizia; Berta, Graziella

    2008-01-01

    The effects of a high concentration of zinc on two registered clones of poplar (Populus alba Villafranca and Populus nigra Jean Pourtet), inoculated or not with two arbuscular mycorrhizal fungi (Glomus mosseae or Glomus intraradices) before transplanting them into polluted soil, were investigated, with special regard to the extent of root colonization by the fungi, plant growth, metal accumulation in the different plant organs, and leaf polyamine concentration. Zinc accumulation was lower in Jean Pourtet than in Villafranca poplars, and it was mainly translocated to the leaves; the metal inhibited mycorrhizal colonization, compromised plant growth, and, in Villafranca, altered the putrescine profile in the leaves. Most of these effects were reversed or reduced in plants pre-inoculated with G. mosseae. Results indicate that poplars are suitable for phytoremediation purposes, confirming that mycorrhizal fungi can be useful for phytoremediation, and underscore the importance of appropriate combinations of plant genotypes and fungal symbionts. - Inoculation with arbuscular mycorrhizal fungi can improve poplar tolerance to heavy metals in phytoremediation programmes

  1. Effect of nitrate supply and mycorrhizal inoculation on characteristics of tobacco root plasma membrane vesicles.

    Science.gov (United States)

    Moche, Martin; Stremlau, Stefanie; Hecht, Lars; Göbel, Cornelia; Feussner, Ivo; Stöhr, Christine

    2010-01-01

    Plant plasma membrane (pm) vesicles from mycorrhizal tobacco (Nicotiana tabacum cv. Samsun) roots were isolated with negligible fungal contamination by the aqueous two-phase partitioning technique as proven by fatty acid analysis. Palmitvaccenic acid became apparent as an appropriate indicator for fungal membranes in root pm preparations. The pm vesicles had a low specific activity of the vanadate-sensitive ATPase and probably originated from non-infected root cells. In a phosphate-limited tobacco culture system, root colonisation by the vesicular arbuscular mycorrhizal fungus, Glomus mosseae, is inhibited by external nitrate in a dose-dependent way. However, detrimental high concentrations of 25 mM nitrate lead to the highest colonisation rate observed, indicating that the defence system of the plant is impaired. Nitric oxide formation by the pm-bound nitrite:NO reductase increased in parallel with external nitrate supply in mycorrhizal roots in comparison to the control plants, but decreased under excess nitrate. Mycorrhizal pm vesicles had roughly a twofold higher specific activity as the non-infected control plants when supplied with 10-15 mM nitrate.

  2. 31P NMR for the study of P metabolism and translocation in arbuscular mycorrhizal fungi

    DEFF Research Database (Denmark)

    Rasmussen, N.; Lloyd, D.C.; Ratcliffe, R.G.

    2000-01-01

    spectra of excised AM fungi and mycorrhizal roots contained signals from polyphosphate (PolyP), which were absent in the spectra of nonmycorrhizal roots. This demonstrated that the P-i taken up by the fungus was transformed into PolyP with a short chain length. The spectra of excised AM fungi revealed...

  3. Impacts of farm management upon arbuscular mycorrhizal fungi and production and utilization of inoculum

    Science.gov (United States)

    Arbuscular mycorrhizal [AM] fungi are naturally-occurring soil fungi that form a mutualistic symbiosis with the roots of most crop plants. The plant benefits through increased: nutrient uptake from the soil, disease resistance, and water stress resistance. Optimal utilization of AM fungi is essen...

  4. Take advantage of mycorrhizal fungi for improved soil fertility and plant health

    Science.gov (United States)

    Arbuscular mycorrhizal [AM] fungi are naturally-occurring soil fungi that form a beneficial symbiosis with the roots of most crops. The plants benefit because the symbiosis increases mineral nutrient uptake, drought resistance, and disease resistance. These characteristics make utilization of AM f...

  5. Interactions between biochar and mycorrhizal fungi in a water-stressed agricultural soil.

    Science.gov (United States)

    Mickan, Bede S; Abbott, Lynette K; Stefanova, Katia; Solaiman, Zakaria M

    2016-08-01

    Biochar may alleviate plant water stress in association with arbuscular mycorrhizal (AM) fungi but research has not been conclusive. Therefore, a glasshouse experiment was conducted to understand how interactions between AM fungi and plants respond to biochar application under water-stressed conditions. A twin chamber pot system was used to determine whether a woody biochar increased root colonisation by a natural AM fungal population in a pasture soil ('field' chamber) and whether this was associated with increased growth of extraradical AM fungal hyphae detected by plants growing in an adjacent ('bait') chamber containing irradiated soil. The two chambers were separated by a mesh that excluded roots. Subterranean clover was grown with and without water stress and harvested after 35, 49 and 63 days from each chamber. When biochar was applied to the field chamber under water-stressed conditions, shoot mass increased in parallel with mycorrhizal colonisation, extraradical hyphal length and shoot phosphorus concentration. AM fungal colonisation of roots in the bait chamber indicated an increase in extraradical mycorrhizal hyphae in the field chamber. Biochar had little effect on AM fungi or plant growth under well-watered conditions. The biochar-induced increase in mycorrhizal colonisation was associated with increased growth of extraradical AM fungal hyphae in the pasture soil under water-stressed conditions.

  6. ARBUSCULAR MYCORRHIZAL IN THE GROWTH OF LEGUMINOUS TREES ON COALMINE WASTE ENRICHED SUBSTRATE

    Directory of Open Access Journals (Sweden)

    Shantau Camargo Gomes Stoffel

    2016-06-01

    Full Text Available The objective of this work was to evaluate the effects of arbuscular mycorrhizal inoculation in the growth, colonization and absorption of P and trace elements of leguminous trees on coal mine wastes. Independent assays for Mimosa scabrella Benth. (common name bracatinga, Mimosa bimucronata (DC. Kuntze (maricá and Parapiptadenia rigida (Benth. Brenan (angico-vermelho were carried out in a greenhouse on an entirely casualized experimental delineation composed of six treatments. Five coal mine autochthonous arbuscular mycorrhizal fungal isolates were tested, including Acaulospora colombiana, Acaulospora morrowiae, Dentiscutata heterogama, Rhizophagus clarus and Rhizophagus irregulars, aside from a control treatment, with four replications each. Results show that arbuscular mycorrhizal colonization was greater than 60% for Mimosa species, and up to 26% for Parapiptadenia. Overall, the fungal inoculation promoted better plant growth, with increments of up to 1430%. Phosphorous absorption was favored, especially when inoculation was done with A. colombiana, R. irregularis and A. morrowiae. Even though there was a conclusive reduction in the levels of trace elements in the plant´s shoots, the inoculation with those species of fungi promoted significant increments in the accumulated levels of As, Cu, Zn and Cr for all plant species tested. Therefore, arbuscular mycorrhizal fungi play important roles in these poor, degraded and often contaminated environments.

  7. Cultivation of flax in spoil-bank clay: Mycorrhizal inoculation vs. high organic amendments

    Czech Academy of Sciences Publication Activity Database

    Püschel, David; Rydlová, Jana; Sudová, Radka; Gryndler, Milan

    2008-01-01

    Roč. 171, č. 6 (2008), s. 872-877 ISSN 1436-8730 R&D Projects: GA MŠk 1M0571 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z50200510 Keywords : arbuscular mycorrhizal fungi * compost * flax Subject RIV: EF - Botanics Impact factor: 1.284, year: 2008

  8. Native grass facilitates mycorrhizal colonisation and P uptake of tree seedlings in two anthropogenic substrates

    Czech Academy of Sciences Publication Activity Database

    Batkhuugyin, Enkhtuya; Pöschl, M.; Vosátka, Miroslav

    2005-01-01

    Roč. 166, 1-4 (2005), s. 217-236 ISSN 0049-6979 R&D Projects: GA ČR(CZ) GA526/99/0895 Institutional research plan: CEZ:AV0Z60050516 Keywords : degraded ecosystems * arbuscular mycorrhizal fungi * phosphorus transfer Subject RIV: EF - Botanics Impact factor: 1.258, year: 2005

  9. Biology, ecology and evolution of the family Gigasporaceae, arbuscular mycorrhizal fungi (Glomeromycota)

    NARCIS (Netherlands)

    Souza, Francisco Adriano de

    2005-01-01

    Research described in this thesis focused on biological, ecological and evolutionary aspects of Arbuscular Mycorrhizal Fungi (AMF), and in particular of the family Gigasporaceae (Gigaspora and Scutellospora, genera). This study had two major objectives. The first objective was to obtain better

  10. Taxon-specific PCR primers to detect two inconspicuous arbuscular mycorrhizal fungi from temperate agricultural grassland

    NARCIS (Netherlands)

    Gamper, H.A.; Leuchtmann, A.

    2007-01-01

    Taxon-specific polymerase chain reaction (PCR) primers enable detection of arbuscular mycorrhizal fungi (AMF, Glomeromycota) in plant roots where the fungi lack discriminative morphological and biochemical characters. We designed and validated pairs of new PCR primers targeted to the flanking

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

    DEFF Research Database (Denmark)

    Opik, M; Moora, Mari; Liira, Jaan

    2006-01-01

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

  12. Arbuscular mycorrhizal fungi increase organic carbon decomposition under elevated carbon dioxide

    Science.gov (United States)

    A major goal of climate change research is to understand whether and how terrestrial ecosystems can sequester more carbon to mitigate rising atmospheric carbon dioxide (CO2) levels. The stimulation of arbuscular mycorrhizal fungi (AMF) by elevated atmospheric CO2 has been assumed to be a major mecha...

  13. Arbuscular mycorrhizal fungal diversity and natural enemies promote coexistence of tropical tree species

    Science.gov (United States)

    Benedicte Bachelot; María Uriarte; Krista L. McGuire; Jill Thompson; Jess Zimmerman

    2017-01-01

    Negative population feedbacks mediated by natural enemies can promote species coexistence at the community scale through disproportionate mortality of numerically dominant (common) tree species. Simultaneously, associations with arbuscular mycorrhizal fungi (AMF) can result in positive effects on tree populations. Coupling data on seedling foliar damage from herbivores...

  14. Effect of biochar soil-amendments on Allium porrum growth, arbuscular mycorrhizal fungus colonization

    Science.gov (United States)

    Aims: Examine the interaction of biochar addition and arbuscular mycorrhizal [AM] fungus inoculation upon growth and Zn and Cu uptake by Allium porrum L. in heavy metal amended soil mix, and relate these responses to physicochemical properties of the biochars. Methods: The experiment was a complete ...

  15. Fungicidal seed coatings exert minor effects on arbuscular mycorrhizal fungi and plant nutrient content

    Science.gov (United States)

    Aims: Determine if contemporary, seed-applied fungicidal formulations inhibit colonization of plant roots by arbuscular mycorrhizal (AM) fungi, plant development, or plant nutrient content during early vegetative stages of several commodity crops. Methods: We evaluated seed-applied commercial fungic...

  16. Interaction between root growth allocation and mycorrhizal fungi in soil with patchy P distribution

    Czech Academy of Sciences Publication Activity Database

    Felderer, B.; Jansa, Jan; Schulin, R.

    2013-01-01

    Roč. 373, 1-2 (2013), s. 569-582 ISSN 0032-079X Institutional support: RVO:61388971 Keywords : Preferential root growth * Arbuscular mycorrhizal fungi * Lotus japonicus Subject RIV: EE - Microbiology, Virology Impact factor: 3.235, year: 2013

  17. Comparing arbuscular mycorrhizal communities of individual plants in a grassland biodiversity experiment

    NARCIS (Netherlands)

    Van de Voorde, T.F.J.; Van der Putten, W.H.; Gamper, H.A.; Hol, W.H.G.; Bezemer, T.M.

    2010-01-01

    Plants differ greatly in the soil organisms colonizing their roots. However, how soil organism assemblages of individual plant roots can be influenced by plant community properties remains poorly understood. We determined the composition of arbuscular mycorrhizal fungi (AMF) in Jacobaea vulgaris

  18. pH measurement of tubular vacuoles of an arbuscular mycorrhizal fungus, Gigaspora margarita.

    Science.gov (United States)

    Funamoto, Rintaro; Saito, Katsuharu; Oyaizu, Hiroshi; Aono, Toshihiro; Saito, Masanori

    2015-01-01

    Arbuscular mycorrhizal fungi play an important role in phosphate supply to the host plants. The fungal hyphae contain tubular vacuoles where phosphate compounds such as polyphosphate are accumulated. Despite their importance for the phosphate storage, little is known about the physiological properties of the tubular vacuoles in arbuscular mycorrhizal fungi. As an indicator of the physiological state in vacuoles, we measured pH of tubular vacuoles in living hyphae of arbuscular mycorrhizal fungus Gigaspora margarita using ratio image analysis with pH-dependent fluorescent probe, 6-carboxyfluorescein. Fluorescent images of the fine tubular vacuoles were obtained using a laser scanning confocal microscope, which enabled calculation of vacuolar pH with high spatial resolution. The tubular vacuoles showed mean pH of 5.6 and a pH range of 5.1-6.3. These results suggest that the tubular vacuoles of arbuscular mycorrhizal fungi have a mildly acidic pH just like vacuoles of other fungal species including yeast and ectomycorrhizal fungi.

  19. Arbuscular mycorrhizal fungi mediated uptake of 137Cs in leek and ryegrass

    International Nuclear Information System (INIS)

    Rosen, Klas; Weiliang, Zhong; Maertensson, Anna

    2005-01-01

    In a first experiment of soil contaminated with 137 Cs, inoculation with a mixture of arbuscular mycorrhizae enhanced the uptake of 137 Cs by leek under greenhouse conditions, while no effect on the uptake by ryegrass was observed. The mycorrhizal infection frequency in leek was independent of whether the 137 Cs-contaminated soil was inoculated with mycorrhizal spores or not. The lack of mycorrhizae-mediated uptake of 137 Cs in ryegrass could be due to the high root density, which was about four times that of leek, or due to a less well functioning mycorrhizal symbiosis than of leek. In a second experiment, ryegrass was grown for a period of four cuts. Additions of fungi enhanced 137 Cs uptake of all harvests, improved dry weight production in the first cut, and also improved the mycorrhizal infection frequencies in the roots. No differences were obtained between the two fungal inoculums investigated with respect to biomass production or 137 Cs uptake, but root colonization differed. We conclude that, under certain circumstances, mycorrhizae affect plant uptake of 137 Cs. There may be a potential for selecting fungal strains that stimulate 137 Cs accumulation in crops. The use of ryegrass seems to be rather ineffective for remediation of 137 Cs-contaminated soil

  20. Arbuscular mycorrhizal inoculation of peanut in low-fertile tropical soil. II. Alleviation of drought stress

    NARCIS (Netherlands)

    Quilambo, OA; Weissenhorn, I.; Doddema, H; Kuiper, PJC; Stulen, I.

    2005-01-01

    The effect of drought stress and inoculation with an indigenous Mozambican and a commercial arbuscular mycorrhizal (AM) inoculant on root colonization and plant growth and yield was studied in two peanut (Arachis hypogaea L.) cultivars-a traditional, low-yielding Mozambican landrace (Local) and a

  1. Metabolic activity of Glomus intraradices in Arum- and Paris-type arbuscular mycorrhizal colonization

    NARCIS (Netherlands)

    van Aarle, IM; Cavagnaro, TR; Smith, SE; Dickson, S

    Colonization of two plant species by Glomus intraradices was studied to investigate the two morphological types (Arum and Paris), their symbiotic interfaces and metabolic activities. Root pieces and sections were stained to observe the colonization and metabolic activity of all mycorrhizal

  2. Impact of arbuscular mycorrhizal fungi on maize physiology and biochemical response under variable nitrogen levels

    Science.gov (United States)

    Arbuscular mycorrhizal (AM) fungi are known for colonizing plant roots, transporting water and nutrients from the soil to the plant. Therefore, environmental conditions set mainly by soil water and nutrient levels are important determinants of AM function and host plant response. Mechanisms of nitro...

  3. Decline of arbuscular mycorrhizal fungi in northern hardwood forests exposed to chronic nitrogen additions

    Science.gov (United States)

    Linda T.A. van Diepen; Erik A. Lilleskov; Kurt S. Pregitzer; R. Michael Miller

    2007-01-01

    Arbuscular mycorrhizal (AM) fungi are important below-ground carbon (C) sinks that can be sensitive to increased nitrogen (N) availability. The abundance of AM fungi (AMF) was estimated in maple (Acer spp.) fine roots following more than a decade of experimental additions of N designed to simulate chronic atmospheric N deposition.

  4. Facilitation between woody and herbaceous plants that associate with arbuscular mycorrhizal fungi in temperate European forests.

    Science.gov (United States)

    Veresoglou, Stavros D; Wulf, Monika; Rillig, Matthias C

    2017-02-01

    In late-successional environments, low in available nutrient such as the forest understory, herbaceous plant individuals depend strongly on their mycorrhizal associates for survival. We tested whether in temperate European forests arbuscular mycorrhizal (AM) woody plants might facilitate the establishment of AM herbaceous plants in agreement with the mycorrhizal mediation hypothesis. We used a dataset spanning over 400 vegetation plots in the Weser-Elbe region (northwest Germany). Mycorrhizal status information was obtained from published resources, and Ellenberg indicator values were used to infer environmental data. We carried out tests for both relative richness and relative abundance of herbaceous plants. We found that the subset of herbaceous individuals that associated with AM profited when there was a high cover of AM woody plants. These relationships were retained when we accounted for environmental filtering effects using path analysis. Our findings build on the existing literature highlighting the prominent role of mycorrhiza as a coexistence mechanism in plant communities. From a nature conservation point of view, it may be possible to promote functional diversity in the forest understory through introducing AM woody trees in stands when absent.

  5. Transcriptome changes induced by arbuscular mycorrhizal fungi in sunflower (Helianthus annuus L.) roots.

    Science.gov (United States)

    Vangelisti, Alberto; Natali, Lucia; Bernardi, Rodolfo; Sbrana, Cristiana; Turrini, Alessandra; Hassani-Pak, Keywan; Hughes, David; Cavallini, Andrea; Giovannetti, Manuela; Giordani, Tommaso

    2018-01-08

    Arbuscular mycorrhizal (AM) fungi are essential elements of soil fertility, plant nutrition and productivity, facilitating soil mineral nutrient uptake. Helianthus annuus is a non-model, widely cultivated species. Here we used an RNA-seq approach for evaluating gene expression variation at early and late stages of mycorrhizal establishment in sunflower roots colonized by the arbuscular fungus Rhizoglomus irregulare. mRNA was isolated from roots of plantlets at 4 and 16 days after inoculation with the fungus. cDNA libraries were built and sequenced with Illumina technology. Differential expression analysis was performed between control and inoculated plants. Overall 726 differentially expressed genes (DEGs) between inoculated and control plants were retrieved. The number of up-regulated DEGs greatly exceeded the number of down-regulated DEGs and this difference increased in later stages of colonization. Several DEGs were specifically involved in known mycorrhizal processes, such as membrane transport, cell wall shaping, and other. We also found previously unidentified mycorrhizal-induced transcripts. The most important DEGs were carefully described in order to hypothesize their roles in AM symbiosis. Our data add a valuable contribution for deciphering biological processes related to beneficial fungi and plant symbiosis, adding an Asteraceae, non-model species for future comparative functional genomics studies.

  6. Arbuscular mycorrhizal inoculation of peanut in low-fertile tropical soil : I. Host-fungus compatibility

    NARCIS (Netherlands)

    Quilambo, OA; Weissenhorn, I.; Kuiper, P.J C; Stulen, I.

    2005-01-01

    The effects of inoculation with an indigenous Mozambican and a commercial arbuscular mycorrhizal (AM) inoculant on two peanut (Arachis hypogaea L.) cultivars, a traditional, low-yielding Mozambican landrace (Local) and a modern, high-yielding cultivar (Falcon), were tested in a non-sterile and

  7. Mycorrhizal Fungal Community of Poplars Growing on Pyrite Tailings Contaminated Site near the River Timok

    Directory of Open Access Journals (Sweden)

    Marina Katanić

    2015-06-01

    Full Text Available Background and Purpose: Mycorrhizal fungi are of high importance for functioning of forest ecosystems and they could be used as indicators of environmental stress. The aim of this research was to analyze ectomycorrhizal community structure and to determine root colonization rate with ectomycorrhizal, arbuscular mycorrhizal and endophytic fungi of poplars growing on pyrite tailings contaminated site near the river Timok (Eastern Serbia. Materials and Methods: Identification of ectomycorrhizal types was performed by combining morphological and anatomical characterization of ectomycorrhizae with molecular identification approach, based on sequencing of the nuclear ITS rRNA region. Also, colonization of poplar roots with ectomycorrhizal, arbuscular mycorrhizal and dark septated endophytic fungi were analysed with intersection method. Results and Conclusions: Physico-chemical analyses of soil from studied site showed unfavourable water properties of soil, relatively low pH and high content of heavy metals (copper and zinc. In investigated samples only four different ectomycorrhizal fungi were found. To the species level were identified Thelephora terrestris and Tomentella ellisi, while two types remained unidentified. Type Thelephora terrestris made up 89% of all ectomycorrhizal roots on studied site. Consequently total values of Species richness index and Shannon-Weaver diversity index were 0.80 and 0.43, respectively. No structures of arbuscular mycorrhizal fungi were recorded. Unfavourable environmental conditions prevailing on investigated site caused decrease of ectomycorrhizal types diversity. Our findings point out that mycorrhyzal fungal community could be used as an appropriate indicator of environmental changes.

  8. Carbon flow from plant to arbuscular mycorrhizal fungi is reduced under phosphorus fertilization

    Czech Academy of Sciences Publication Activity Database

    Konvalinková, Tereza; Püschel, David; Řezáčová, Veronika; Gryndlerová, Hana; Jansa, Jan

    2017-01-01

    Roč. 419, 1-2 (2017), s. 319-333 ISSN 0032-079X R&D Projects: GA MŠk(CZ) LK11224; GA ČR(CZ) GA14-19191S Institutional support: RVO:61388971 Keywords : Arbuscular mycorrhiza * Carbon allocation * Mycorrhizal cost Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.052, year: 2016

  9. Host identity is a dominant driver of mycorrhizal fungal community composition during ecosystem development.

    Science.gov (United States)

    Martínez-García, Laura B; Richardson, Sarah J; Tylianakis, Jason M; Peltzer, Duane A; Dickie, Ian A

    2015-03-01

    Little is known about the response of arbuscular mycorrhizal fungal communities to ecosystem development. We use a long-term soil chronosequence that includes ecosystem progression and retrogression to quantify the importance of host plant identity as a factor driving fungal community composition during ecosystem development. We identified arbuscular mycorrhizal fungi and plant species from 50 individual roots from each of 10 sites spanning 5-120 000 yr of ecosystem age using terminal restriction fragment length polymorphism (T-RFLP), Sanger sequencing and pyrosequencing. Arbuscular mycorrhizal fungal communities were highly structured by ecosystem age. There was strong niche differentiation, with different groups of operational taxonomic units (OTUs) being characteristic of early succession, ecosystem progression and ecosystem retrogression. Fungal alpha diversity decreased with ecosystem age, whereas beta diversity was high at early stages and lower in subsequent stages. A total of 39% of the variance in fungal communities was explained by host plant and site age, 29% of which was attributed to host and the interaction between host and site (24% and 5%, respectively). The strong response of arbuscular mycorrhizal fungi to ecosystem development appears to be largely driven by plant host identity, supporting the concept that plant and fungal communities are tightly coupled rather than independently responding to habitat. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  10. Effects of arbuscular mycorrhizal fungi on the root uptake and translocation of radiocaesium

    International Nuclear Information System (INIS)

    Dupre de Boulois, Herve; Delvaux, Bruno; Declerck, Stephane

    2005-01-01

    Because mycorrhizal fungi are intimately associated with plant roots, their importance in radionuclide (RN) recycling and subsequent dispersion into the biosphere has received an increasing interest. Recently, the capacity of arbuscular mycorrhizal fungi to take up and translocate radiocaesium to their host was demonstrated. However, the relative contribution of these processes in comparison to the ones of roots remains unknown. Here, the respective contributions of the hyphae of a Glomus species and the transformed carrot (Daucus carota L.) roots on radiocaesium uptake and translocation were compared and quantified. We observed that radiocaesium uptake by hyphae was significantly lower as compared to that of the roots, while the opposite was noted for radiocaesium translocation/uptake ratio. We also observed that the intraradical fungal structures might induce a local accumulation of radiocaesium and concurrently reduce its translocation within mycorrhizal roots. We believe that intraradical fungal structures might induce the down-regulation of radiocaesium channels involved in the transport processes of radiocaesium towards the xylem. - Radiocaesium root uptake and translocation is affected by an arbuscular mycorrhizal fungus

  11. Effects of arbuscular mycorrhizal fungi on the root uptake and translocation of radiocaesium

    Energy Technology Data Exchange (ETDEWEB)

    Dupre de Boulois, Herve [Universite catholique de Louvain, Mycotheque de l' Universite catholique de Louvain (MUCL), Unite de Microbiologie, Place Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium); Delvaux, Bruno [Universite catholique de Louvain, Unite des Sciences du Sol, Place Croix du Sud 2/10, 1348 Louvain-la-Neuve (Belgium); Declerck, Stephane [Universite catholique de Louvain, Mycotheque de l' Universite catholique de Louvain (MUCL), Unite de Microbiologie, Place Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium)]. E-mail: declerck@mbla.ucl.ac.be

    2005-04-01

    Because mycorrhizal fungi are intimately associated with plant roots, their importance in radionuclide (RN) recycling and subsequent dispersion into the biosphere has received an increasing interest. Recently, the capacity of arbuscular mycorrhizal fungi to take up and translocate radiocaesium to their host was demonstrated. However, the relative contribution of these processes in comparison to the ones of roots remains unknown. Here, the respective contributions of the hyphae of a Glomus species and the transformed carrot (Daucus carota L.) roots on radiocaesium uptake and translocation were compared and quantified. We observed that radiocaesium uptake by hyphae was significantly lower as compared to that of the roots, while the opposite was noted for radiocaesium translocation/uptake ratio. We also observed that the intraradical fungal structures might induce a local accumulation of radiocaesium and concurrently reduce its translocation within mycorrhizal roots. We believe that intraradical fungal structures might induce the down-regulation of radiocaesium channels involved in the transport processes of radiocaesium towards the xylem. - Radiocaesium root uptake and translocation is affected by an arbuscular mycorrhizal fungus.

  12. Organic Nitrogen-Driven Stimulation of Arbuscular Mycorrhizal Fungal Hyphae Correlates with Abundance of Ammonia Oxidizers

    Czech Academy of Sciences Publication Activity Database

    Bukovská, Petra; Gryndler, Milan; Gryndlerová, Hana; Püschel, David; Jansa, Jan

    2016-01-01

    Roč. 4, MAY 12 (2016), s. 711 ISSN 1664-302X R&D Projects: GA ČR GAP504/12/1665; GA MŠk(CZ) LK11224 Institutional support: RVO:61388971 Keywords : soil heterogeneity * organic amendments * arbuscular mycorrhizal (AM) fungi Subject RIV: EE - Microbiology, Virology Impact factor: 4.076, year: 2016

  13. BIOFERTILIZATION WITH RHIZOBACTERIA AND A CONSORTIUM OF ARBUSCULAR MYCORRHIZAL FUNGI IN CITRUS ROOTSTOCKS

    Directory of Open Access Journals (Sweden)

    Roberto Gregorio Chiquito-Contreras

    2012-11-01

    Full Text Available Biofertilization of plants with rhizobacteria and vesicular arbuscular mycorrhizae (mycorrhizal consortium, potentially promotes plant growth and health, and reduces the use of agrochemicals. The effect of individual and combined biofertilization with three strains of rhizobacteria and the mycorrhizal consortium (MTZ-1 was evaluated under nursery conditions on the growth of rootstocks of Citrus volkameriana and Rangpur lime grafted with Tahiti lime. Plants were inoculated individually and combined with the rhizobacteria strains FCA-8, FCA-56 and FCA-60 of Pseudomonas putida, and with MTZ-1; 50 % fertilization also was applied (18-46-00 N-P-K and compared with controls that received nursery management and 100 % fertilization. A split-plot experimental design with five replications per treatment was established. Individual and combined biofertilization with the three strains of bacteria and MTZ-1 positively promoted the growth of C. volkameriana, and Rangpur lime grafted with Tahiti lime, similar to the control with 100 % fertilization. The nutrient content of Tahiti lime leaves was similar to the control for both rootstocks. The presence of rhizobacterial and mycorrhizal populations in the combined biofertilization treatments demonstrated a positive synergism in the colonization of rootstock roots. Results demonstrate the potential of the three strains of P. putida and the MTZ-1 mycorrhizal consortium on the promotion of plant growth and assimilation of nutrients.

  14. Mycorrhizal symbiosis and seedling performance of the frankincense tree (Boswellia papyrifera)

    NARCIS (Netherlands)

    Hizikias, E.B.

    2011-01-01

    Arid areas are characterized by a seasonal climate with a long dry period. In such stressful

    environment, resource availability is driven by longterm and shorterm rainfall pulses.

    Arbuscular Mycorrhizal (AM) fungi enhance access to moisture and nutrients and thereby

  15. Stimulation of vesicular-arbuscular mycorrhizal fungi by mycotrophic and nonmycotrophic plant root systems.

    Science.gov (United States)

    Schreiner, R P; Koide, R T

    1993-08-01

    Transformed root cultures of three nonmycotrophic and one mycotrophic plant species stimulated germination and hyphal growth of the vesicular-arbuscular mycorrhizal fungus Glomus etunicatum (Becker & Gerd.) in a gel medium. However, only roots of the mycotrophic species (carrot) supported continued hyphal exploration after 3 to 4 weeks and promoted appressoria formation by G. etunicatum.

  16. Mycorrhizal responsiveness of aerobic rice genotypes is negatively correlated with their zinc uptake when nonmycorhizal

    NARCIS (Netherlands)

    Gao, X.; Kuyper, T.W.; Zou, C.; Zhang, F.; Hoffland, E.

    2007-01-01

    Plant Zn uptake from low Zn soils can be increased by Zn-mobilizing chemical rhizosphere processes. We studied whether inoculation with arbuscular mycorrhizal fungi (AMF) can be an additional or an alternative strategy. We determined the effect of AMF inoculation on growth performance and Zn uptake

  17. Stimulation of Vesicular-Arbuscular Mycorrhizal Fungi by Mycotrophic and Nonmycotrophic Plant Root Systems

    OpenAIRE

    Schreiner, R. Paul; Koide, Roger T.

    1993-01-01

    Transformed root cultures of three nonmycotrophic and one mycotrophic plant species stimulated germination and hyphal growth of the vesicular-arbuscular mycorrhizal fungus Glomus etunicatum (Becker & Gerd.) in a gel medium. However, only roots of the mycotrophic species (carrot) supported continued hyphal exploration after 3 to 4 weeks and promoted appressoria formation by G. etunicatum.

  18. Impact of arbuscular mycorrhizal fungi (AMF) on cucumber growth and phosphorus uptake under cold stress

    Czech Academy of Sciences Publication Activity Database

    Ma, J.; Janoušková, Martina; Li, Y.; Yu, X.; Yan, Y.; Zou, Z.; He, C.

    2015-01-01

    Roč. 42, č. 12 (2015), s. 1158-1167 ISSN 1445-4408 R&D Projects: GA MŠk LH12178 Institutional support: RVO:67985939 Keywords : mycorrhizal growth response * phosphate transporter * Rhizophagus irregularis Subject RIV: ED - Physiology Impact factor: 2.491, year: 2015

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  20. Large-scale diversity patterns in spore communities of Arbuscular mycorrhizal fungi [Chapter 2

    Science.gov (United States)

    Javier Alvarez-Sanchez; Nancy C. Johnson; Anita Antoninka; V. Bala Chaudhary; Matthew K. Lau; Suzanne M. Owen; Patricia Gauadarrama; Silvia. Castillo

    2010-01-01

    Surprising little is known about the factors controlling Arbuscular Mycorrhizal (AM) fungal diversity and distribution patterns. A better understanding of these factors is necessary before mycorrhizas can be effectively managed for their benefits in ecosystem restoration and agriculture. The goal of this chapter is to examine the relationships between AM fungal...

  1. EFFECTS OF MYCORRHIZAL FUNGI ON IN-VITRO NITROGEN RESPONSE OF SOME DUTCH INDIGENOUS ORCHID SPECIES

    NARCIS (Netherlands)

    DIJK, E; ECK, ND

    The effect of mycorrhizal infection on the response to mineral nitrogen was studied in Orchis morio L., Dactylorhiza praetermissa (Druce) Soo var. junialis (Vermin.) Sengh., Dactylorhiza majalis (Reichb.) Hunt & Summerh., and Dactylorhiza incarnara (L.) Soo, using two strains of Ceratorhiza sp. and

  2. Reduced mycorrhizal responsiveness leads to increased competitive tolerance in an invasive exotic plant

    Science.gov (United States)

    Lauren P. Waller; Ragan M. Callaway; John N. Klironomos; Yvette K. Ortega; John L. Maron

    2016-01-01

    1. Arbuscular mycorrhizal (AM) fungi can exert a powerful influence on the outcome of plant–plant competition. Since some exotic plants interact differently with soil biota such as AM fungi in their new range, range-based shifts in AM responsiveness could shift competitive interactions between exotic and resident plants, although this remains poorly studied. 2. We...

  3. Arbuscular mycorrhizal impacts on competitive interactions between Acacia etbaica and Boswellia papyrifera seedlings under drought stress

    NARCIS (Netherlands)

    Birhane, E.; Sterck, F.J.; Bongers, F.; Kuyper, T.W.

    2014-01-01

    Aims Arbuscular mycorrhizal fungi can have a substantial effect on the water and nutrient uptake by plants and the competition between plants in harsh environments where resource availability comes in pulses. In this study we focus on interspecific competition between Acaia etbaica and Boswellia

  4. Arbuscular mycorrhizal symbiosis induces strigolactone biosynthesis under drought and improves drought tolerance in lettuce and tomato

    NARCIS (Netherlands)

    Ruiz-Lozano, J.M.; Aroca, R.; Zamarreno, A.M.; Molina, S.; Andreo Jimenez, B.; Porcel, R.; Garcia-Mina, J.M.; Ruyter-Spira, C.P.; Lopez-Raez, J.A.

    2016-01-01

    Arbuscular mycorrhizal (AM) symbiosis alleviates drought stress in plants. However, the intimate mechanisms involved, as well as its effect on the production of signalling molecules associated with the host plant–AM fungus interaction remains largely unknown. In the present work, the effects of

  5. Arbuscular mycorrhizal fungal community composition associated with Juniperus brevifolia in native Azorean forest

    Czech Academy of Sciences Publication Activity Database

    Drumonde Melo, C.; Luna, S.; Krüger, Claudia; Walker, C.; Mendonça, D.; Fonseca, H. M. A. C.; Jaizme-Vega, M.; da Camara Machado, A.

    2017-01-01

    Roč. 79, FEB 2017 (2017), s. 48-61 ISSN 1146-609X Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * Juniperus bravifolia * native forests Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 1.652, year: 2016

  6. Limited impact of arbuscular mycorrhizal fungi on clones of Agrostis capillaris with different heavy metal tolerance

    Czech Academy of Sciences Publication Activity Database

    Doubková, Pavla; Sudová, Radka

    2016-01-01

    Roč. 99, MAR 2016 (2016), s. 78-88 ISSN 0929-1393 R&D Projects: GA AV ČR(CZ) KJB600050636 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal symbiosis * heavy metal contamination * lead, zinc, copper and cadmium Subject RIV: EH - Ecology, Behaviour Impact factor: 2.786, year: 2016

  7. Carbon availability for the fungus triggers nitrogen uptake and transport in the arbuscular mycorrhizal symbiosis

    Science.gov (United States)

    The arbuscular mycorrhizal (AM) symbiosis is characterized by a transfer of nutrients in exchange for carbon. We tested the effect of the carbon availability for the AM fungus Glomus intraradices on nitrogen (N) uptake and transport in the symbiosis. We followed the uptake and transport of 15N and ...

  8. Mycorrhizal Symbiosis and Local Adaptation in Aster amellus: A Field Transplant Experiment

    Czech Academy of Sciences Publication Activity Database

    Pánková, Hana; Raabová, J.; Münzbergová, Zuzana

    2014-01-01

    Roč. 9, č. 4 (2014), s. 1-7, e93967 E-ISSN 1932-6203 R&D Projects: GA ČR GAP504/10/1486 Institutional support: RVO:67985939 Keywords : mycorrhizal symbiosis * local adaptation * Aster amellus Subject RIV: EF - Botanics Impact factor: 3.234, year: 2014

  9. The symbiosis with arbuscular mycorrhizal fungi contributes to plant tolerance to serpentine edaphic stress

    Czech Academy of Sciences Publication Activity Database

    Doubková, Pavla; Suda, Jan; Sudová, Radka

    2012-01-01

    Roč. 4, č. 1 (2012), s. 56-64 ISSN 0038-0717 R&D Projects: GA AV ČR KJB600050812 Institutional research plan: CEZ:AV0Z60050516 Keywords : serpentine syndrome * arbuscular mycorrhizal fungi * reciprocal transplant experiment Subject RIV: EF - Botanics Impact factor: 3.654, year: 2012

  10. Quantification of arbuscular mycorrhizal fungal DNA in roots: how important is material preservation?

    Czech Academy of Sciences Publication Activity Database

    Janoušková, Martina; Püschel, David; Hujslová, Martina; Slavíková, Renata; Jansa, Jan

    2015-01-01

    Roč. 25, č. 3 (2015), s. 205-214 ISSN 0940-6360 R&D Projects: GA MŠk(CZ) LK11224 Institutional support: RVO:61388971 Keywords : Arbuscular mycorrhizal fungi * Intraradical colonization * PCR inhibition Subject RIV: EE - Microbiology, Virology Impact factor: 3.252, year: 2015

  11. Activation of Symbiosis Signaling by Arbuscular Mycorrhizal Fungi in Legumes and Rice[OPEN

    Science.gov (United States)

    Sun, Jongho; Miller, J. Benjamin; Granqvist, Emma; Wiley-Kalil, Audrey; Gobbato, Enrico; Maillet, Fabienne; Cottaz, Sylvain; Samain, Eric; Venkateshwaran, Muthusubramanian; Fort, Sébastien; Morris, Richard J.; Ané, Jean-Michel; Dénarié, Jean; Oldroyd, Giles E.D.

    2015-01-01

    Establishment of arbuscular mycorrhizal interactions involves plant recognition of diffusible signals from the fungus, including lipochitooligosaccharides (LCOs) and chitooligosaccharides (COs). Nitrogen-fixing rhizobial bacteria that associate with leguminous plants also signal to their hosts via LCOs, the so-called Nod factors. Here, we have assessed the induction of symbiotic signaling by the arbuscular mycorrhizal (Myc) fungal-produced LCOs and COs in legumes and rice (Oryza sativa). We show that Myc-LCOs and tetra-acetyl chitotetraose (CO4) activate the common symbiosis signaling pathway, with resultant calcium oscillations in root epidermal cells of Medicago truncatula and Lotus japonicus. The nature of the calcium oscillations is similar for LCOs produced by rhizobial bacteria and by mycorrhizal fungi; however, Myc-LCOs activate distinct gene expression. Calcium oscillations were activated in rice atrichoblasts by CO4, but not the Myc-LCOs, whereas a mix of CO4 and Myc-LCOs activated calcium oscillations in rice trichoblasts. In contrast, stimulation of lateral root emergence occurred following treatment with Myc-LCOs, but not CO4, in M. truncatula, whereas both Myc-LCOs and CO4 were active in rice. Our work indicates that legumes and non-legumes differ in their perception of Myc-LCO and CO signals, suggesting that different plant species respond to different components in the mix of signals produced by arbuscular mycorrhizal fungi. PMID:25724637

  12. Arbuscular mycorrhizal symbiosis alleviates drought stress imposed on Knautia arvensis plants in serpentine soil

    Czech Academy of Sciences Publication Activity Database

    Doubková, Pavla; Vlasáková, E.; Sudová, Radka

    2013-01-01

    Roč. 370, 1-2 (2013), s. 149-161 ISSN 0032-079X R&D Projects: GA AV ČR KJB600050812 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * drought * serpentine soil Subject RIV: EF - Botanics Impact factor: 3.235, year: 2013

  13. Mutualism Persistence and Abandonment during the Evolution of the Mycorrhizal Symbiosis.

    Science.gov (United States)

    Maherali, Hafiz; Oberle, Brad; Stevens, Peter F; Cornwell, William K; McGlinn, Daniel J

    2016-11-01

    Mutualistic symbioses with mycorrhizal fungi are widespread in plants. The majority of plant species associate with arbuscular mycorrhizal (AM) fungi. By contrast, the minority associate with ectomycorrhizal (EM) fungi, have abandoned the symbiosis and are nonmycorrhizal (NM), or engage in an intermediate, weakly AM symbiosis (AMNM). To understand the processes that maintain the mycorrhizal symbiosis or cause its loss, we reconstructed its evolution using a ∼3,000-species seed plant phylogeny integrated with mycorrhizal state information. Reconstruction indicated that the common ancestor of seed plants most likely associated with AM fungi and that the EM, NM, and AMNM states descended from the AM state. Direct transitions from the AM state to the EM and NM states were infrequent and generally irreversible, implying that natural selection or genetic constraint could promote stasis once a particular state evolved. However, the evolution of the NM state was more frequent via an indirect pathway through the AMNM state, suggesting that weakening of the AM symbiosis is a necessary precursor to mutualism abandonment. Nevertheless, reversions from the AMNM state back to the AM state were an order of magnitude more likely than transitions to the NM state, suggesting that natural selection favors the AM symbiosis over mutualism abandonment.

  14. Development of arbuscular mycorrhizal biotechnology and industry: current achievements and bottlenecks

    Czech Academy of Sciences Publication Activity Database

    Vosátka, Miroslav; Látr, A.; Gianinazzi, S.; Albrechtová, Jana

    2013-01-01

    Roč. 58, 1-3 (2013), s. 29-37 ISSN 0334-5114 R&D Projects: GA MPO FR-TI1/299 Institutional research plan: CEZ:AV0Z60050516 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * sustainable agriculture * inoculum quality Subject RIV: EF - Botanics Impact factor: 0.941, year: 2013

  15. Gr and hp-1 tomato mutants unveil unprecedented interactions between arbuscular mycorrhizal symbiosis and fruit ripening

    Science.gov (United States)

    The roots of plants interact with soil mycorrhizal fungi to facilitate soil nutrient acquisition by the plant and carbon transfer to the fungus. Here we use tomato fruit ripening mutations to demonstrate that this root interaction communicates with and supports genetic mechanisms associated with th...

  16. Mycorrhizal associations of trees have different indirect effects on organic matter decomposition

    Science.gov (United States)

    Melanie K. Taylor; Richard A. Lankau; Nina Wurzburger; Franciska de Vries

    2016-01-01

    1. Organic matter decomposition is the main process by which carbon (C) is lost from terrestrialecosystems, and mycorrhizal associations of plants (i.e. arbuscular mycorrhizas (AM) and ectomycorrhizas(ECM)) may have different indirect effects on this loss pathway. AM and ECM plants differin the soil...

  17. Efflux of hydraulically lifted water from mycorrhizal fungal hyphae during imposed drought

    Science.gov (United States)

    Querejeta, José Ignacio; Allen, Michael F

    2008-01-01

    Apart from improving plant and soil water status during drought, it has been suggested that hydraulic lift (HL) could enhance plant nutrient capture through the flow of mineral nutrients directly from the soil to plant roots, or by maintaining the functioning of mycorrhizal fungi. We evaluated the extent to which the diel cycle of water availability created by HL covaries with the efflux of HL water from the tips of extramatrical (external) mycorrhizal hyphae, and the possible effects on biogeochemical processes. Phenotypic mycorrhizal fungal variables, such as total and live hyphal lengths, were positively correlated with HL efflux from hyphae, soil water potential (dawn), and plant response variables (foliar 15N). The efflux of HL water from hyphae was also correlated with bacterial abundance and soil enzyme activity (P), and the moistening of soil organic matter. Such findings indicate that the efflux of HL water from the external mycorrhizal mycelia may be a complementary explanation for plant nutrient acquisition and survival during drought. PMID:19704776

  18. Carbon availability triggers fungal nitrogen uptake and transport in arbuscular mycorrhizal symbiosis.

    NARCIS (Netherlands)

    Fellbaum, C.R.; Gachomo, E.W.; Beesetty, Y.; Choudhari, S.; Strahan, G.D.; Pfeffer, P.E.; Kiers, E.T.; Bücking, H.

    2012-01-01

    The arbuscular mycorrhizal (AM) symbiosis, formed between the majority of land plants and ubiquitous soil fungi of the phylum Glomeromycota, is responsible for massive nutrient transfer and global carbon sequestration. AM fungi take up nutrients from the soil and exchange them against

  19. Misconceptions on the application of biological market theory to the mycorrhizal symbiosis

    NARCIS (Netherlands)

    Kiers, E.T.; West, S.A.; Wyatt, G.A.K.; Garner, A.; Bücking, H.; Werner, G.D.A.

    2016-01-01

    Letter to the Editor — The symbiosis between plants and arbuscular mycorrhizal fungi has been described as a biological market based on evidence that plants supply more carbohydrates to fungal partners that provide more soil nutrients, and vice versa 1–4 . A recent paper by Walder and van der

  20. Mycorrhizal hyphae as ecological niche for highly specialized hypersymbionts – or just soil free-riders?

    Directory of Open Access Journals (Sweden)

    Jan eJansa

    2013-05-01

    Full Text Available Mycorrhizal fungi interconnect two different kinds of environments, namely the plant roots with the surrounding soil. This widespread coexistence of plants and fungi has important consequences for plant mineral nutrition, water acquisition, carbon allocation, tolerance to abiotic and biotic stresses and interplant competition. Yet some current research indicates a number of important roles to be played by hyphae-associated microbes, in addition to the hyphae themselves, in foraging for and acquisition of soil resources and in transformation of organic carbon in the soil-plant systems. We critically review the available scientific evidence for the theory that the surface of mycorrhizal hyphae in soil is colonized by highly specialized microbial communities, and that these fulfill important functions in the ecology of mycorrhizal fungal hyphae such as accessing recalcitrant forms of mineral nutrients, and production of signaling and other compounds in the vicinity of the hyphae. The validity of another hypothesis will then be addressed, namely that the specific associative microbes are rewarded with exclusive access to fungal carbon, which would qualify them as hypersymbionts (i.e. symbionts of symbiotic mycorrhizal fungi. Thereafter, we ask whether recruitment of functionally different microbial assemblages by the hyphae is required under different soil conditions (questioning what evidence is available for such an effect, and we identify knowledge gaps requiring further attention.

  1. Community structure of arbuscular mycorrhizal fungi in undisturbed vegetation revealed by analyses of LSU rdna sequences

    DEFF Research Database (Denmark)

    Rosendahl, Søren; Holtgrewe-Stukenbrock, Eva

    2004-01-01

    Arbuscular mycorrhizal fungi (AMF) form a mutualistic symbiosis with plant roots and are found in most ecosystems. In this study the community structure of AMF in a clade of the genus Glomus was examined in undisturbed costal grassland using LSU rDNA sequences amplified from roots of Hieracium...

  2. Protocol: using virus-induced gene silencing to study the arbuscular mycorrhizal symbiosis in Pisum sativum

    DEFF Research Database (Denmark)

    Grønlund, Mette; Olsen, Anne; Johansen, Elisabeth

    2010-01-01

    , the available PEBV-VIGS protocols are inadequate for studying genes involved in the symbiosis with arbuscular mycorrhizal fungi (AMF). Here we describe a PEBV-VIGS protocol suitable for reverse genetics studies in pea of genes involved in the symbiosis with AMF and show its effectiveness in silencing genes...... involved in the early and late stages of AMF symbiosis....

  3. Arbuscular mycorrhizal fungi mediated uptake of {sup 137}Cs in leek and ryegrass

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, Klas; Weiliang, Zhong; Maertensson, Anna [Department of Soil Sciences, Swedish University of Agricultural Sciences P.O. Box 7014, SE-750 07 Uppsala (Sweden)

    2005-02-15

    In a first experiment of soil contaminated with {sup 137}Cs, inoculation with a mixture of arbuscular mycorrhizae enhanced the uptake of {sup 137}Cs by leek under greenhouse conditions, while no effect on the uptake by ryegrass was observed. The mycorrhizal infection frequency in leek was independent of whether the {sup 137}Cs-contaminated soil was inoculated with mycorrhizal spores or not. The lack of mycorrhizae-mediated uptake of {sup 137}Cs in ryegrass could be due to the high root density, which was about four times that of leek, or due to a less well functioning mycorrhizal symbiosis than of leek. In a second experiment, ryegrass was grown for a period of four cuts. Additions of fungi enhanced {sup 137}Cs uptake of all harvests, improved dry weight production in the first cut, and also improved the mycorrhizal infection frequencies in the roots. No differences were obtained between the two fungal inoculums investigated with respect to biomass production or {sup 137}Cs uptake, but root colonization differed. We conclude that, under certain circumstances, mycorrhizae affect plant uptake of {sup 137}Cs. There may be a potential for selecting fungal strains that stimulate {sup 137}Cs accumulation in crops. The use of ryegrass seems to be rather ineffective for remediation of {sup 137}Cs-contaminated soil.

  4. Mycorrhizal responses under elevated CO2 : combining fungal and plant perspectives

    NARCIS (Netherlands)

    Alberton, O.

    2008-01-01

    The rising level of atmospheric carbon dioxide (CO2) combined with increased nutrient (especially nitrogen) availability are predicted to have substantial impacts on plant growth and the functioning of ecosystems. Soil micro-organisms, especially mycorrhizal fungi that form mutualistic associations

  5. Production of native arbuscular mycorrhizal fungi inoculum under different environmental conditions

    Directory of Open Access Journals (Sweden)

    Yamir Torres-Arias

    Full Text Available Abstract In order to obtain an arbuscular mycorrhizal fungi (AMF native inoculum from Sierra de Moa and determine the most appropriate conditions for its big scale production, four light and temperature combinations were tested in three plant species (Calophyllum antillanum, Talipariti elatum and Paspalum notatum. Growth and development parameters, as well as the mycorrhizal functioning of the seedlings were evaluated. The natural light treatment under high temperatures (L-H was the most suitable for the growth and development of the three plant species, showing the highest total biomass values, mainly of root, and a positive root-shoot ratio balance. This treatment also promoted higher values of root mycorrhizal colonization, external mycelium and AMF spore density. A total of 38 AMF species were identified among the plants and environmental conditions tested. Archaeospora sp.1, Glomus sp.5, Glomus brohultii and G. glomerulatum were observed in all the treatments. The L-H condition can be recommended for native inoculum production, as it promotes a better expression of the AM symbiosis and an elevated production of mycorrhizal propagules.

  6. Influence of nitrogen and phosphorus sources on mycorrhizal lettuces under organic farming

    Science.gov (United States)

    Scotti, Riccardo; Seguel, Alex; Cornejo, Pablo; Rao, Maria A.; Borie, Fernando

    2010-05-01

    Arbuscular mycorrhizal fungi (AMF) develop symbiotic associations with plants roots. These associations are very common in the natural environment and can provide a range of benefits to the host plant. AMF improve nutrition, enhance resistance to soil-borne pests and disease, increase resistance to drought and tolerance to heavy metals, and contribute to a better soil structure. However, agricultural intensive managements, such as the use of mineral fertilizes, pesticides, mouldboard tillage, monocultures and use of non-mycorrhizal crops, are detrimental to AMF. As a consequence, agroecosystems are impoverished in AMF and may not provide the full range of benefits to the crop. Organic farming systems may be less unfavourable to AMF because they exclude the use of water-soluble fertilisers and most pesticides, and generally they plan diverse crop rotations. The AMF develop the most common type of symbiosis in nature: about 90% of the plants are mycorrhizal and many agricultural crops are mycorrhizal. One of more mycorrhizal crops is lettuce, that is very widespread in intensive agricultural under greenhouse. Therefore, cultivated lettuce is know to be responsive to mycorrhizal colonization which can reach 80% of root length and contribute to phosphorus and nitrogen absorption by this plant specie. For this work four different lettuce cultivars (Romana, Milanesa, Grande Lagos and Escarola) were used to study mycorrhization under organic agricultural system, supplying compost from agricultural waste (1 kg m-2) as background fertilization for all plots, red guano as phosphorus source (75 U ha-1 and 150 U ha-1 of P2O5), lupine flour as nitrogen source (75 and 150 U/ha of N) and a combination of both. Lettuce plants were cultivated under greenhouse and after two months of growing, plants were harvested and dried and fresh weight of lettuce roots and shoots were evaluated. The number of spores, percentage of colonization, total mycelium and glomalin content were also

  7. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Science.gov (United States)

    Vannette, Rachel L.; Hunter, Mark D.; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)—which all produce toxic cardenolides—with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense. PMID:24065971

  8. Growth and mycorrhizal community structure of Pinus sylvestris seedlings following the addition of forest litter.

    Science.gov (United States)

    Aucina, Algis; Rudawska, Maria; Leski, Tomasz; Skridaila, Audrius; Riepsas, Edvardas; Iwanski, Michal

    2007-08-01

    We report the effects of pine and oak litter on species composition and diversity of mycorrhizal fungi colonizing 2-year-old Pinus sylvestris L. seedlings grown in a bare-root nursery in Lithuania. A layer of pine or oak litter was placed on the surface of the nursery bed soil to mimic natural litter cover. Oak litter amendment appeared to be most favorable for seedling survival, with a 73% survival rate, in contrast to the untreated mineral bed soil (44%). The concentrations of total N, P, K, Ca, and Mg were higher in oak growth medium than in pine growth medium. Relative to the control (pH 6.1), the pH was lower in pine growth medium (5.8) and higher in oak growth medium (6.3). There were also twofold and threefold increases in the C content of growth medium with the addition of pine and oak litter, respectively. Among seven mycorrhizal morphotypes, eight different mycorrhizal taxa were identified: Suillus luteus, Suillus variegatus, Wilcoxina mikolae, a Tuber sp., a Tomentella sp., Cenococcum geophilum, Amphinema byssoides, and one unidentified ectomycorrhizal symbiont. Forest litter addition affected the relative abundance of mycorrhizal symbionts more than their overall representation. This was more pronounced for pine litter than for oak litter, with 40% and 25% increases in the abundance of suilloid mycorrhizae, respectively. Our findings provide preliminary evidence that changes in the supply of organic matter through litter manipulation may have far-reaching effects on the chemistry of soil, thus influencing the growth and survival of Scots pine seedlings and their mycorrhizal communities.

  9. Growth and Mycorrhizal Community Structure of Pinus sylvestris Seedlings following the Addition of Forest Litter▿

    Science.gov (United States)

    Aučina, Algis; Rudawska, Maria; Leski, Tomasz; Skridaila, Audrius; Riepšas, Edvardas; Iwanski, Michal

    2007-01-01

    We report the effects of pine and oak litter on species composition and diversity of mycorrhizal fungi colonizing 2-year-old Pinus sylvestris L. seedlings grown in a bare-root nursery in Lithuania. A layer of pine or oak litter was placed on the surface of the nursery bed soil to mimic natural litter cover. Oak litter amendment appeared to be most favorable for seedling survival, with a 73% survival rate, in contrast to the untreated mineral bed soil (44%). The concentrations of total N, P, K, Ca, and Mg were higher in oak growth medium than in pine growth medium. Relative to the control (pH 6.1), the pH was lower in pine growth medium (5.8) and higher in oak growth medium (6.3). There were also twofold and threefold increases in the C content of growth medium with the addition of pine and oak litter, respectively. Among seven mycorrhizal morphotypes, eight different mycorrhizal taxa were identified: Suillus luteus, Suillus variegatus, Wilcoxina mikolae, a Tuber sp., a Tomentella sp., Cenococcum geophilum, Amphinema byssoides, and one unidentified ectomycorrhizal symbiont. Forest litter addition affected the relative abundance of mycorrhizal symbionts more than their overall representation. This was more pronounced for pine litter than for oak litter, with 40% and 25% increases in the abundance of suilloid mycorrhizae, respectively. Our findings provide preliminary evidence that changes in the supply of organic matter through litter manipulation may have far-reaching effects on the chemistry of soil, thus influencing the growth and survival of Scots pine seedlings and their mycorrhizal communities. PMID:17575001

  10. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species.

    Science.gov (United States)

    Vannette, Rachel L; Hunter, Mark D; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)-which all produce toxic cardenolides-with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense.

  11. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Directory of Open Access Journals (Sweden)

    Rachel L Vannette

    2013-09-01

    Full Text Available Belowground symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above and belowground herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed--which all produce toxic cardenolides--with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in above- and below-ground plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and

  12. Engineering Mycorrhizal Symbioses to Alter Plant Metabolism and Improve Crop Health

    Directory of Open Access Journals (Sweden)

    Katherine E. French

    2017-07-01

    Full Text Available Creating sustainable bioeconomies for the 21st century relies on optimizing the use of biological resources to improve agricultural productivity and create new products. Arbuscular mycorrhizae (phylum Glomeromycota form symbiotic relationships with over 80% of vascular plants. In return for carbon, these fungi improve plant health and tolerance to environmental stress. This symbiosis is over 400 million years old and there are currently over 200 known arbuscular mycorrhizae, with dozens of new species described annually. Metagenomic sequencing of native soil communities, from species-rich meadows to mangroves, suggests biologically diverse habitats support a variety of mycorrhizal species with potential agricultural, medical, and biotechnological applications. This review looks at the effect of mycorrhizae on plant metabolism and how we can harness this symbiosis to improve crop health. I will first describe the mechanisms that underlie this symbiosis and what physiological, metabolic, and environmental factors trigger these plant-fungal relationships. These include mycorrhizal manipulation of host genetic expression, host mitochondrial and plastid proliferation, and increased production of terpenoids and jasmonic acid by the host plant. I will then discuss the effects of mycorrhizae on plant root and foliar secondary metabolism. I subsequently outline how mycorrhizae induce three key benefits in crops: defense against pathogen and herbivore attack, drought resistance, and heavy metal tolerance. I conclude with an overview of current efforts to harness mycorrhizal diversity to improve crop health through customized inoculum. I argue future research should embrace synthetic biology to create mycorrhizal chasses with improved symbiotic abilities and potentially novel functions to improve plant health. As the effects of climate change and anthropogenic disturbance increase, the global diversity of arbuscular mycorrhizal fungi should be monitored

  13. Continuation of Iranshahri Thoughts in Kalileh va Demne

    Directory of Open Access Journals (Sweden)

    Bijan Zahirinav

    2010-10-01

    Full Text Available In this essay, Iranshahri’s thoughts such as ideal king, divine charisma, togetherness of religion and kingdom, justice, truth etc in kalileh va Demneh are investigated. In Kalileh and Demneh, kingdom is a divine gift and the king is at the center of the state affairs. Therefore, affection and kindness must be imprinted on his forehead, otherwise he would be a devilish creature who disturbs governing orders of the universe. He must metaphysically be supported in the circus of governmental affairs, and this is possible only by divine charisma. Such a king must be decorated with justice ornament, so that every body does his best in his own special class and approaches the salvation of soul. The king must also be decorated with accomplishments such as battle assistance and with virtues such as religion assistance. He must strengthen the social connection by “truth”. Basically, without truth life has no harmony because falsehood diverts life form its regular direction. But finally, with the dominance of divine forces over devilish ones, utopia, which is a secure place for releasing from disorder and injustice is proven to be true. Therefore, we conclude that Kalileh and Demneh has a contribution to the continuation of Iranshahri’s thoughts and also to the historical and cultural continuation of Iran in transition to the Islamic period.

  14. Seed coating with arbuscular mycorrhizal fungi as an ecotechnological approach for sustainable agricultural production of common wheat (Triticum aestivum L.)

    Czech Academy of Sciences Publication Activity Database

    Oliviera, R. S.; Rocha, I.; Ma, Y.; Vosátka, Miroslav; Freitas, H.

    2016-01-01

    Roč. 79, č. 7 (2016), s. 329-337 ISSN 1528-7394 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * phosphorus uptake * soil Subject RIV: GC - Agronomy Impact factor: 2.731, year: 2016

  15. Plant and fungal gene expression in mycorrhizal protocorms of the orchid Serapias vomeracea colonized by Tulasnella calospora.

    Science.gov (United States)

    Balestrini, Raffaella; Nerva, Luca; Sillo, Fabiano; Girlanda, Mariangela; Perotto, Silvia

    2014-01-01

    Little is known on the molecular bases of plant-fungal interactions in orchid mycorrhiza. We developed a model system to investigate gene expression in mycorrhizal protocorms of Serapias vomeracea colonised by Tulasnella calospora. Our recent results with a small panel of genes as indicators of plant response to mycorrhizal colonization indicate that genes related with plant defense were not significantly up-regulated in mycorrhizal tissues. Here, we used laser microdissection to investigate whether expression of some orchid genes was restricted to specific cell types. Results showed that SvNod1, a S. vomeracea nodulin-like protein containing a plastocyanin-like domain, is expressed only in protocorm cells containing intracellular fungal hyphae. In addition, we investigated a family of fungal zinc metallopeptidases (M36). This gene family has expanded in the T. calospora genome and RNA-Seq experiments indicate that some members of the M36 metallopeptidases family are differentially regulated in orchid mycorrhizal protocorms.

  16. Arbuscular mycorrhizal fungi reveal distinct patterns of anastomosis formation and hyphal healing mechanisms between different phylogenic groups

    NARCIS (Netherlands)

    De Souza, F.A.; Fernández, F.; Delmas, N.S.; Declerck, S.

    2005-01-01

    The significance of anastomosis formation and the hyphal healing mechanism (HHM) for functionality and integrity of the arbuscular mycorrhizal (AM) fungal mycelial network remains poorly documented. Four Glomeraceae and three Gigasporaceae were cultured monoxenically. Anastomosis formation was

  17. Comparison of commonly used primer sets for evaluating arbuscular mycorrhizal fungal communities: Is there a universal solution?

    Czech Academy of Sciences Publication Activity Database

    Kohout, P.; Sudová, R.; Janoušková, M.; Čtvrtlíková, Martina; Hejda, M.; Pánková, H.; Slavíková, R.; Štajerová, K.; Vosátka, M.; Sýkorová, Z.

    2014-01-01

    Roč. 68, January (2014), s. 482-493 ISSN 0038-0717 Institutional support: RVO:60077344 Keywords : arbuscular mycorrhizal fungi * primers * diversity Subject RIV: EF - Botanics Impact factor: 3.932, year: 2014

  18. Identification of a vesicular-arbuscular mycorrhizal fungus by using monoclonal antibodies in an enzyme-linked immunosorbent assay.

    Science.gov (United States)

    Wright, S F; Morton, J B; Sworobuk, J E

    1987-09-01

    Spore morphology is currently used to identify species of vesicular-arbuscular mycorrhizal fungi. We report the first use of a highly specific immunological method for identification of a vesicular-arbuscular mycorrhizal fungus. Two monoclonal antibodies were produced against Glomus occultum. Monoclonal antibodies reacted strongly with both spores and hyphae in an indirect enzyme-linked immunosorbent assay. All other mycorrhizal (29 species) and nonmycorrhizal (5 species) fungi tested were nonreactive with the monoclonal antibodies. A single spore of G. occultum was detectable in the presence of high numbers of spores of other vesicular-arbuscular mycorrhizal fungi. Variation in the reaction of G. occultum isolates from West Virginia, Florida, and Colombia suggests that monoclonal antibodies may differentiate strains.

  19. Mycorrhizal infection, phosphorus uptake, and phenology in Ranunculus adoneus: implications for the functioning of mycorrhizae in alpine systems.

    Science.gov (United States)

    Mullen, R B; Schmidt, S K

    1993-05-01

    Phosphorus levels, phenology of roots and shoots, and development of vesicular arbuscular mycorrhizal (VAM) fungi were monitored for two years in natural populations of the perennial alpine herb, Ranunculus adoneus. The purpose of this study was to understand how phosphorus uptake relates to the phenology of R. adoneus and to ascertain whether arbusculus, fungal structures used for nutrient transfer, were present when maximum phosphorus accumulation was occurring. Arbuscules were only present for a few weeks during the growing season of R. adoneus and their presence corresponded with increased phosphorus accumulation in both the roots and shoots of R. adoneus. In addition, phosphorus accumulation and peaks in mycorrhizal development occurred well after plant reproduction and most plant growth had occurred. The late season accumulation of phosphorus by mycorrhizal roots of R. adoneus is stored for use during early season growth and flowering the following spring. In this way R. adoneus can flower before soils thaw and root or mycorrhizal nutrient uptake can occur.

  20. Transfer of 65Zn in maize -mycorrhizal systems: a potential mechanism to alleviate Zn deficiency in maize

    International Nuclear Information System (INIS)

    Subramanian, K.S.; Tenshia, Virgin

    2017-01-01

    Mycorrhizas are root associated fungi and obligate symbionts known to improve the nutritional status of the host plant as a direct consequence of transfer of slowly diffusing nutrients such as zinc. The Zn use efficiency by crops hardly exceeds 2-5 per cent and major portion of the Zn gets accumulated in soil in various pools which are not available to plants. Further, mycorrhizal symbiosis alters the chemical and biochemical properties of rhizosphere that affect the isotopic parameters such as A value, E value and L value. These parameters were measured for both mycorrhizal and non-mycorrhizal maize plants. A pot culture experiment was conducted to determine the availability of Zn using isotopic dilution techniques. Maize plants were grown in pots inoculated with (M+) or without (M-) mycorrhizal fungus Glomus intraradices. Tagged 65 ZnSO 4 was applied to soil at the time of sowing

  1. Ploidy-specific symbiotic interactions: divergence of mycorrhizal fungi between cytotypes of the Gymnadenia conopsea group (Orchidaceae)

    Czech Academy of Sciences Publication Activity Database

    Těšitelová, T.; Jersáková, J.; Roy, M.; Kubátová, B.; Těšitel, J.; Urfus, Tomáš; Trávníček, Pavel; Suda, Jan

    2013-01-01

    Roč. 199, č. 4 (2013), s. 1022-1033 ISSN 0028-646X Institutional support: RVO:67985939 Keywords : cytometry * mycorrhizal symbiosis * polyploidy Subject RIV: EF - Botanics Impact factor: 6.545, year: 2013

  2. Methods for estimating and comparing VA outpatient drug benefits with the private sector.

    Science.gov (United States)

    Render, Marta L; Nowak, John; Hammond, Emmett K; Roselle, Gary

    2003-06-01

    To estimate and compare Veterans Health Administration (VA) expenditures for outpatient pharmaceuticals for veterans at six VA facilities with hypothetical private sector costs. Using the VA Pharmacy Benefits Management Strategic Health Care Group (PBM) database, we extracted data for all dispensed outpatient prescriptions from the six study sites over federal fiscal year 1999. After extensive data validation, we converted prescriptions to the same units and merged relevant VA pricing information by National Drug Code to Redbook listed average wholesale price and the Medicaid maximal allowable charge, where available. We added total VA drug expenditures to personnel cost from the pharmacy portion of that medical center's cost distribution report. Hypothetical private sector payments were $200.8 million compared with an aggregate VA budget of $118.8 million. Using National Drug Code numbers, 97% of all items dispensed from the six facilities were matched to private sector price data. Nonmatched pharmaceuticals were largely generic over-the-counter pain relievers and commodities like alcohol swabs. The most commonly prescribed medications reflect the diseases and complaints of an older male population: pain, cardiovascular problems, diabetes, and depression or other psychiatric disorders. Use of the VA PBM database permits researchers to merge expenditure and prescription data to patient diagnoses and sentinel events. A critical element in its use is creating similar units among the systems. Such data sets permit a deeper view of the variability in drug expenditures, an important sector of health care whose inflation has been disproportionate to that of the economy and even health care.

  3. Flexural Stiffness of Myosin Va Subdomains as Measured from Tethered Particle Motion

    Science.gov (United States)

    Michalek, Arthur J.; Kennedy, Guy G.; Warshaw, David M.; Ali, M. Yusuf

    2015-01-01

    Myosin Va (MyoVa) is a processive molecular motor involved in intracellular cargo transport on the actin cytoskeleton. The motor's processivity and ability to navigate actin intersections are believed to be governed by the stiffness of various parts of the motor's structure. Specifically, changes in calcium may regulate motor processivity by altering the motor's lever arm stiffness and thus its interhead communication. In order to measure the flexural stiffness of MyoVa subdomains, we use tethered particle microscopy, which relates the Brownian motion of fluorescent quantum dots, which are attached to various single- and double-headed MyoVa constructs bound to actin in rigor, to the motor's flexural stiffness. Based on these measurements, the MyoVa lever arm and coiled-coil rod domain have comparable flexural stiffness (0.034 pN/nm). Upon addition of calcium, the lever arm stiffness is reduced 40% as a result of calmodulins potentially dissociating from the lever arm. In addition, the flexural stiffness of the full-length MyoVa construct is an order of magnitude less stiff than both a single lever arm and the coiled-coil rod. This suggests that the MyoVa lever arm-rod junction provides a flexible hinge that would allow the motor to maneuver cargo through the complex intracellular actin network. PMID:26770194

  4. Effects of inspired CO2, hyperventilation, and time on VA/Q inequality in the dog

    Science.gov (United States)

    Tsukimoto, K.; Arcos, J. P.; Schaffartzik, W.; Wagner, P. D.; West, J. B.

    1992-01-01

    In a recent study by Tsukimoto et al. (J. Appl. Physiol. 68: 2488-2493, 1990), CO2 inhalation appeared to reduce the size of the high ventilation-perfusion ratio (VA/Q) mode commonly observed in anesthetized mechanically air-ventilated dogs. In that study, large tidal volumes (VT) were used during CO2 inhalation to preserve normocapnia. To separate the influences of CO2 and high VT on the VA/Q distribution in the present study, we examined the effect of inspired CO2 on the high VA/Q mode using eight mechanically ventilated dogs (4 given CO2, 4 controls). The VA/Q distribution was measured first with normal VT and then with increased VT. In the CO2 group at high VT, data were collected before, during, and after CO2 inhalation. With normal VT, there was no difference in the size of the high VA/Q mode between groups [10.5 +/- 3.5% (SE) of ventilation in the CO2 group, 11.8 +/- 5.2% in the control group]. Unexpectedly, the size of the high VA/Q mode decreased similarly in both groups over time, independently of the inspired PCO2, at a rate similar to the fall in cardiac output over time. The reduction in the high VA/Q mode together with a simultaneous increase in alveolar dead space (estimated by the difference between inert gas dead space and Fowler dead space) suggests that poorly perfused high VA/Q areas became unperfused over time. A possible mechanism is that elevated alveolar pressure and decreased cardiac output eliminate blood flow from corner vessels in nondependent high VA/Q regions.

  5. Assessment of mycorrhizal colonisation and soil nutrients in unmanaged fire-impacted soils from two target restoration sites

    Energy Technology Data Exchange (ETDEWEB)

    Dias, J. M.; Oliveira, R. S.; Franco, A. R.; Ritz, K.; Nunan, N.; Castro, P. M. L.

    2010-07-01

    The mycorrhizal colonisation of plants grown in unmanaged soils from two restoration sites with a fire history in Northern Portugal was evaluated from the perspective of supporting restoration programmes. To promote restoration of original tree stands, Quercus ilex L. and Pinus pinaster Ait. were used as target species on two sites, denoted Site 1 and 2 respectively. The aim of the study was to assess whether mycorrhizal propagules that survived fire episodes could serve as in situ inoculum sources, and to analyse the spatial distribution of soil nutrients and mycorrhizal parameters. In a laboratory bioassay, P. pinaster and Q. ilex seedlings were grown on soils from the target sites and root colonisation by ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungi was determined. The ECM root colonisation levels found indicated that soil from Site 2 contained sufficient ECM propagules to serve as a primary source of inoculum for P. pinaster. The low levels of ECM and AM colonisation obtained on the roots of plants grown in soil from Site 1 indicated that the existing mycorrhizal propagules might be insufficient for effective root colonisation of Q. ilex. Different ECM morphotypes were found in plants grown in soil from the two sites. At Site 2 mycorrhizal parameters were found to be spatially structured, with significant differences in ECM colonisation and soil P concentrations between regions of either side of an existing watercourse. The spatial distribution of mycorrhizal propagules was related to edaphic parameters (total C and extractable P), and correlations between soil nutrients and mycorrhizal parameters were found. (Author) 31 refs.

  6. Dual Inoculation with Mycorrhizal and Saprotrophic Fungi Applicable in Sustainable Cultivation Improves the Yield and Nutritive Value of Onion

    OpenAIRE

    Albrechtova, Jana; Latr, Ales; Nedorost, Ludovit; Pokluda, Robert; Posta, Katalin; Vosatka, Miroslav

    2012-01-01

    The aim of this paper was to test the use of dual microbial inoculation with mycorrhizal and saprotrophic fungi in onion cultivation to enhance yield while maintaining or improving the nutritional quality of onion bulbs. Treatments were two-factorial: (1) arbuscular mycorrhizal fungi (AMF): the mix corresponding to fungal part of commercial product Symbivit (Glomus etunicatum, G. microaggregatum, G. intraradices, G. claroideum, G. mosseae, and G. geosporum) (M1) or the single-fungus inoculum ...

  7. Competitive interactions between a nonmycorrhizal invasive plant, Alliaria petiolata, and a suite of mycorrhizal grassland, old field, and forest species.

    Science.gov (United States)

    Poon, Gary T; Maherali, Hafiz

    2015-01-01

    The widespread invasion of the nonmycorrhizal biennial plant, Alliaria petiolata in North America is hypothesized to be facilitated by the production of novel biochemical weapons that suppress the growth of mycorrhizal fungi. As a result, A. petiolata is expected to be a strong competitor against plant species that rely on mycorrhizal fungi for nutrient uptake services. If A. petiolata is also a strong competitor for soil resources, it should deplete nutrients to levels lower than can be tolerated by weaker competitors. Because the negative effect of losing the fungal symbiont for mycorrhizal plants is greatest when nutrients are low, the ability of A. petiolata to simultaneously suppress fungi and efficiently take up soil nutrients should further strengthen its competitive ability against mycorrhizal plants. To test this hypothesis, we grew 27 mycorrhizal tree, forb and grass species that are representative of invaded habitats in the absence or presence of competition with A. petiolata in soils that had previously been experimentally planted with the invader or left as a control. A history of A. petiolata in soil reduced plant available forms of nitrogen by >50% and phosphorus by 17% relative to control soil. Average mycorrhizal colonization of competitor species was reduced by >50% in A. petiolata history versus control soil. Contrary to expectations, competition between A. petiolata and other species was stronger in control than history soil. The invader suppressed the biomass of 70% of competitor species in control soil but only 26% of species in history soil. In addition, A. petiolata biomass was reduced by 56% in history versus control soil, whereas the average biomass of competitor species was reduced by 15%. Thus, our results suggest that the negative effect of nutrient depletion on A. petiolata was stronger than the negative effect of suppressing mycorrhizal colonization on competitor species. These findings indicate that the inhibitory potential of A

  8. From root to fruit: RNA-Seq analysis shows that arbuscular mycorrhizal symbiosis may affect tomato fruit metabolism

    OpenAIRE

    Inès, Zouari; Alessandra, Salvioli; Matteo, Chialva; Mara, Novero; Laura, Miozzi; Gian Carlo, Tenore; Paolo, Bagnaresi; Paola, Bonfante

    2014-01-01

    Background Tomato (Solanum lycopersicum) establishes a beneficial symbiosis with arbuscular mycorrhizal (AM) fungi. The formation of the mycorrhizal association in the roots leads to plant-wide modulation of gene expression. To understand the systemic effect of the fungal symbiosis on the tomato fruit, we used RNA-Seq to perform global transcriptome profiling on Moneymaker tomato fruits at the turning ripening stage. Results Fruits were collected at 55 days after flowering, from plants coloni...

  9. Can Cd translocation in Oryza sativa L. be attenuated by arbuscular mycorrhizal fungi in the presence of EDTA?

    Science.gov (United States)

    Huang, Xiaochen; An, Guangnan; Zhu, Shishu; Wang, Li; Ma, Fang

    2018-04-01

    Arbuscular mycorrhizal (AM) fungi play an important role in plant tolerance of heavy metal contamination. In this study, a pot experiment was conducted to illustrate the effects of the two AM fungi species Funneliformis mosseae (Fm) and Rhizophagus irregularis (Ri) on plant growth of Oryza sativa L. either with or without ethylenediamine tetraacetate (EDTA) addition and during exposure to five Cd concentrations (in the range of 0-5 mg kg -1 ). The results showed that Fm inoculation achieved greater mycorrhizal colonization and mycorrhizal dependency indexes than Ri inoculation. In addition, the effects of AM fungi on Cd biosorption and translocation in rice were also investigated in the presence of EDTA. Despite cooperative adsorption, the Freundlich isotherm could describe the biosorption effects of Cd on rice roots regardless of AM fungi inoculation or EDTA addition. Cd concentrations in mycorrhizal roots increased but decreased in mycorrhizal shoots in contrast to the control treatment. Although EDTA addition negatively inhibited the uptake of Cd to mycorrhizal shoots, lower translocation factor (TF) and bioconcentration factor (BCF) were still observed in treatments with EDTA compared to control treatment. Our findings suggest that Ri and Fm inoculation enhanced Cd immobilization in the roots, thus preventing Cd entry into the food chain during exposure to low and high Cd stress, respectively.

  10. Quantification of the proliferation of arbuscular mycorrhizal fungi in soil

    Science.gov (United States)

    Zhang, Ning; Lilje, Osu; McGee, Peter

    2013-04-01

    Good soil structure is important for sustaining agricultural production and preserving functions of the soil ecosystem. Soil aggregation is a critically important component of soil structure. Stable aggregates enable water infiltration, gas exchange for biological activities of plant roots and microorganisms, living space and surfaces for soil microbes, and contribute to stabilization of organic matter and storage of organic carbon (OC) in soil. Soil aggregation involves fine roots, organic matter and hyphae of arbuscular mycorrhizal (AM) fungi. Hyphal proliferation is essential for soil aggregation and sequestration of OC in soil. We do not yet have a mechanism to directly quantify the density of hyphae in soil. Organic materials and available phosphorus are two of the major factors that influence fungi in soil. Organic materials are a source of energy for saprotrophic microbes. Fungal hyphae increase in the presence of organic matter. Phosphorus is an important element usually found in ecosystems. The low availability of phosphorus limits the biological activity of microbes. AM fungi benefit plants by delivering phosphorus to the root system. However, the density and the length of hyphae of AM fungi do not appear to be influenced by available phosphorus. A number of indirect methods have been used to visualize distribution of fungi in soil. Reliable analyses of soil are limited because of soil characteristics. Soils are fragile, and fragility limits opportunity for non-destructive analysis. The soil ecosystem is complex. Soil particles are dense and the density obscures the visualization of fungal hyphae. Fungal hyphae are relatively fine and information at the small scale (hyphae of AM fungi. Hyphae were quantified in an artificial soil matrix using micro-computer aided tomography. Micro-computer aided tomography provides three dimensional images of hyphal ramification through electron lucent materials and enables the visualization and quantification of hyphae

  11. Effects of different P-sources in soil on increasing growth and mineral uptake of mycorrhizal Vitis vinifera L. (cv Victoria vines

    Directory of Open Access Journals (Sweden)

    Nikolaos Nikolaou

    2002-12-01

    Full Text Available The effect of different P-sources on growth, leaf chemical composition, and fruit soluble solids and acid content was evaluated in mycorrhizal Victoria grapevine variety gralted onto the rootstocks 3309C or 11 OR. Mycorrhizal and non mycorrhizal plants were grown in 20 L pots containing 20 kg soil supplemented with different P-forms: (Calcium bis-dihydrogen-phosphate, tri-calcium phosphate, aluminium phosphate, iron (III phosphate with different solubility, equivalent to 90 kg P.ha-1. The percent of mycorrhizal root colonization was higher in insoluble P-form treatments compared to control or to soluble P-form treatment (CaDP, ranging from 66 to 84 % in treatments receiving insoluble P, from 36.67 to 38.33 % in control and from 25.33 to 27.33 % in soluble P-form treatments. The roots of 110R rootstock showed higher colonization rate compared to the 3309C. Mycorrhizal colonization increased both the pruning weight and number of nodes of the vines, up to 9 and 1.9 times respectively, according to the rootstock- P form combination. Mycorrhizal vines showed increased leaf concentrations in N, P, K, Ca. Fruit total soluble solids of mycorrhizal vines were about 30 % lower compared with those of the non mycorrhizal vines. Both factors, mycorrhizal colonization and P-forms had no significant effect in fruit titratable acidity.

  12. Beneficial contribution of the arbuscular mycorrhizal fungus, Rhizophagus irregularis, in the protection of Medicago truncatula roots against benzo[a]pyrene toxicity.

    Science.gov (United States)

    Lenoir, Ingrid; Fontaine, Joël; Tisserant, Benoît; Laruelle, Frédéric; Lounès-Hadj Sahraoui, Anissa

    2017-07-01

    Arbuscular mycorrhizal fungi are able to improve plant establishment in polluted soils but little is known about the genes involved in the plant protection against pollutant toxicity by mycorrhization, in particular in the presence of polycyclic aromatic hydrocarbons (PAH). The present work aims at studying in both symbiotic partners, Medicago truncatula and Rhizophagus irregularis: (i) expression of genes putatively involved in PAH tolerance (MtSOD, MtPOX, MtAPX, MtGST, MtTFIIS, and MtTdp1α), (ii) activities of antioxidant (SOD, POX) and detoxification (GST) enzymes, and (iii) H 2 O 2 and the heavy PAH, benzo[a]pyrene (B[a]P) accumulation. In the presence of B[a]P, whereas induction of the enzymatic activities was detected in R. irregularis and non-mycorrhizal roots as well as upregulation of the gene expressions in the non-mycorrhizal roots, downregulation of the gene expressions and decrease of enzyme activities were observed in mycorrhizal roots. Moreover, B[a]P increased H 2 O 2 production in non-mycorrhizal roots and in R. irregularis but not in mycorrhizal roots. In addition, a lower B[a]P bioaccumulation in mycorrhizal roots was measured in comparison with non-mycorrhizal roots. Being less affected by pollutant toxicity, mycorrhizal roots did not activate any defense mechanism either at the gene expression regulation level or at the enzymatic level.

  13. Analysis of VaR on Stock Investing%股票投资的风险价值VaR分析

    Institute of Scientific and Technical Information of China (English)

    张江红; 唐泉

    2011-01-01

    VaR is a tool to measure financial risk,which is supported and recognized by the international financial community in recent years.For equity portfolios consisting of different market factors or different financial instruments,VaR can reliably evaluate the market risks.In the paper the basic principle and calculation of VaR is introduced,the company stock value at risk has been analyzed using normal method,which company has issued convertible bond and stock.Meanwhile the affect that the issuance of convertible bond to the underlying stock fluctuation has been taken into account in order to provide reference for the different types of investors.%VaR是近年来受到国际金融界广泛支持和认可的一种度量金融风险的工具.对于不同市场因子和不同金融工具的投资组合,VaR可以相对可靠地衡量其市场风险.本文介绍了VaR的基本原理和计算方法,并用正态分布对发行有可转债的上市公司股票的风险价值进行分析,考虑了可转债的发行对标的股票波动的影响,以期为资本市场不同类型的投资者在进行资本投资前估计风险提供参考.

  14. Arbuscular mycorrhizal symbiosis mitigates the negative effects of salinity on durum wheat

    Science.gov (United States)

    Ingraffia, Rosolino; Giambalvo, Dario; Frenda, Alfonso Salvatore

    2017-01-01

    Arbuscular mycorrhizal (AM) symbiosis is generally considered to be effective in ameliorating the plant tolerance to salt stress. Unfortunately, the comprehension of the mechanisms implicated in salinity stress alleviation by AM symbiosis is far from being complete. Thus, an experiment was performed by growing durum wheat (Triticum durum Desf.) plants under salt-stress conditions to evaluate the influence of AM symbiosis on both the plant growth and the regulation of a number of genes related to salt stress and nutrient uptake. Durum wheat plants were grown outdoors in pots in absence or in presence of salt stress and with or without AM fungi inoculation. The inoculum consisted of a mixture of spores of Rhizophagus irregularis (formerly Glomus intraradices) and Funneliformis mosseae (formerly G. mosseae). Results indicate that AM symbiosis can alleviate the detrimental effects of salt stress on the growth of durum wheat plants. In fact, under salt stress conditions mycorrhizal plants produced more aboveground and root biomass, had higher N uptake and aboveground N concentration, and showed greater stability of plasma membranes compared to non-mycorrhizal plants. Inoculation with AM fungi had no effect on the expression of the N transporter genes AMT1.1, AMT1.2, and NAR2.2, either under no-stress or salt stress conditions, probably due to the fact that plants were grown under optimal N conditions; on the contrary, NRT1.1 was always upregulated by AM symbiosis. Moreover, the level of expression of the drought stress-related genes AQP1, AQP4, PIP1, DREB5, and DHN15.3 observed in the mycorrhizal stressed plants was markedly lower than that observed in the non-mycorrhizal stressed plants and very close to that observed in the non-stressed plants. Our hypothesis is that, in the present study, AM symbiosis did not increase the plant tolerance to salt stress but instead generated a condition in which plants were subjected to a level of salt stress lower than that of non-mycorrhizal

  15. Arbuscular mycorrhizal symbiosis mitigates the negative effects of salinity on durum wheat.

    Science.gov (United States)

    Fileccia, Veronica; Ruisi, Paolo; Ingraffia, Rosolino; Giambalvo, Dario; Frenda, Alfonso Salvatore; Martinelli, Federico

    2017-01-01

    Arbuscular mycorrhizal (AM) symbiosis is generally considered to be effective in ameliorating the plant tolerance to salt stress. Unfortunately, the comprehension of the mechanisms implicated in salinity stress alleviation by AM symbiosis is far from being complete. Thus, an experiment was performed by growing durum wheat (Triticum durum Desf.) plants under salt-stress conditions to evaluate the influence of AM symbiosis on both the plant growth and the regulation of a number of genes related to salt stress and nutrient uptake. Durum wheat plants were grown outdoors in pots in absence or in presence of salt stress and with or without AM fungi inoculation. The inoculum consisted of a mixture of spores of Rhizophagus irregularis (formerly Glomus intraradices) and Funneliformis mosseae (formerly G. mosseae). Results indicate that AM symbiosis can alleviate the detrimental effects of salt stress on the growth of durum wheat plants. In fact, under salt stress conditions mycorrhizal plants produced more aboveground and root biomass, had higher N uptake and aboveground N concentration, and showed greater stability of plasma membranes compared to non-mycorrhizal plants. Inoculation with AM fungi had no effect on the expression of the N transporter genes AMT1.1, AMT1.2, and NAR2.2, either under no-stress or salt stress conditions, probably due to the fact that plants were grown under optimal N conditions; on the contrary, NRT1.1 was always upregulated by AM symbiosis. Moreover, the level of expression of the drought stress-related genes AQP1, AQP4, PIP1, DREB5, and DHN15.3 observed in the mycorrhizal stressed plants was markedly lower than that observed in the non-mycorrhizal stressed plants and very close to that observed in the non-stressed plants. Our hypothesis is that, in the present study, AM symbiosis did not increase the plant tolerance to salt stress but instead generated a condition in which plants were subjected to a level of salt stress lower than that of non-mycorrhizal

  16. Validation of KENO V.a for the Portsmouth Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Felsher, H.D.; Fentiman, A.W.; Tayloe, R.W.; D'Aquila, D.

    1992-01-01

    At the Portsmouth Gaseous Diffusion Plant, KENO V.a is used to make criticality calculations for complex configurations and a wide range of 235 U enrichments. It is essential that the calculated critical conditions either accurately reflect the true critical state or that the bias from the true critical conditions are well known. Accordingly, a study has been initiated to validate KENO V.a over the ranges of parameters expected to be used when modeling equipment and processes at Portsmouth. Preliminary results of that study are reported in this paper. The ultimate goal of this study is to identify a set of data from existing critical experiments that will exercise all KENO V.a parameters commonly used by Portsmouth's criticality safety personnel. A second goal is to identify a relatively small subset of those experiments that may be run frequently to ensure that KENO V.a provides consistent results

  17. ESTIMATING RISK ON THE CAPITAL MARKET WITH VaR METHOD

    Directory of Open Access Journals (Sweden)

    Sinisa Bogdan

    2015-06-01

    Full Text Available The two basic questions that every investor tries to answer before investment are questions about predicting return and risk. Risk and return are generally considered two positively correlated sizes, during the growth of risk it is expected increase of return to compensate the higher risk. The quantification of risk in the capital market represents the current topic since occurrence of securities. Together with estimated future returns it represents starting point of any investment. In this study it is described the history of the emergence of VaR methods, usefulness in assessing the risks of financial assets. Three main Value at Risk (VaR methodologies are decribed and explained in detail: historical method, parametric method and Monte Carlo method. After the theoretical review of VaR methods it is estimated risk of liquid stocks and portfolio from the Croatian capital market with historical and parametric VaR method, after which the results were compared and explained.

  18. Comparison of historically simulated VaR: Evidence from oil prices

    International Nuclear Information System (INIS)

    Costello, Alexandra; Asem, Ebenezer; Gardner, Eldon

    2008-01-01

    Cabedo and Moya [Cabedo, J.D., Moya, I., 2003. Estimating oil price 'Value at Risk' using the historical simulation approach. Energy Economics 25, 239-253] find that ARMA with historical simulation delivers VaR forecasts that are superior to those from GARCH. We compare the ARMA with historical simulation to the semi-parametric GARCH model proposed by Barone-Adesi et al. [Barone-Adesi, G., Giannopoulos, K., Vosper, L., 1999. VaR without correlations for portfolios of derivative securities. Journal of Futures Markets 19 (5), 583-602]. The results suggest that the semi-parametric GARCH model generates VaR forecasts that are superior to the VaR forecasts from the ARMA with historical simulation. This is due to the fact that GARCH captures volatility clustering. Our findings suggest that Cabedo and Moya's conclusion is mainly driven by the normal distributional assumption imposed on the future risk structure in the GARCH model. (author)

  19. 77 FR 12647 - Fund Availability Under VA's Homeless Providers Grant and Per Diem Program

    Science.gov (United States)

    2012-03-01

    ... women veterans with or without the care of dependent children. 2. Funding Priority 2--VA is offering the... homeless veterans (i.e., veterans who are not incarcerated but are involved in the criminal justice system...

  20. Electronic Health Records: DOD's and VA's Sharing of Information Could Benefit from Improved Management

    National Research Council Canada - National Science Library

    2009-01-01

    ...) and the Department of Veterans Affairs (VA) are required to accelerate the exchange of health information between the departments and to develop systems or capabilities that allow for interoperability...