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Sample records for alters root exudation

  1. Root exudate-induced alterations in Bacillus cereus cell wall contribute to root colonization and plant growth promotion.

    Directory of Open Access Journals (Sweden)

    Swarnalee Dutta

    Full Text Available The outcome of an interaction between plant growth promoting rhizobacteria and plants may depend on the chemical composition of root exudates (REs. We report the colonization of tobacco, and not groundnut, roots by a non-rhizospheric Bacillus cereus (MTCC 430. There was a differential alteration in the cell wall components of B. cereus in response to the REs from tobacco and groundnut. Attenuated total reflectance infrared spectroscopy revealed a split in amide I region of B. cereus cells exposed to tobacco-root exudates (TRE, compared to those exposed to groundnut-root exudates (GRE. In addition, changes in exopolysaccharides and lipid-packing were observed in B. cereus grown in TRE-amended minimal media that were not detectable in GRE-amended media. Cell-wall proteome analyses revealed upregulation of oxidative stress-related alkyl hydroperoxide reductase, and DNA-protecting protein chain (Dlp-2, in response to GRE and TRE, respectively. Metabolism-related enzymes like 2-amino-3-ketobutyrate coenzyme A ligase and 2-methylcitrate dehydratase and a 60 kDa chaperonin were up-regulated in response to TRE and GRE. In response to B. cereus, the plant roots altered their exudate-chemodiversity with respect to carbohydrates, organic acids, alkanes, and polyols. TRE-induced changes in surface components of B. cereus may contribute to successful root colonization and subsequent plant growth promotion.

  2. Casuarina root exudates alter the physiology, surface properties, and plant infectivity of Frankia sp Strain CcI3

    OpenAIRE

    Beauchemin, Nicholas J.; Furnholm, Teal; Lavenus, Julien; Svistoonoff, Sergio; Doumas, Patrick; Bogusz, Didier; Laplaze, Laurent; Tisa, Louis S.

    2012-01-01

    The actinomycete genus Frankia forms nitrogen-fixing symbioses with 8 different families of actinorhizal plants, representing more than 200 different species. Very little is known about the initial molecular interactions between Frankia and host plants in the rhizosphere. Root exudates are important in Rhizobium-legume symbiosis, especially for initiating Nod factor synthesis. We measured differences in Frankia physiology after exposure to host aqueous root exudates to assess their effects on...

  3. An ABC Transporter Mutation Alters Root Exudation of Phytochemicals That Provoke an Overhaul of Natural Soil Microbiota1[C][W][OA

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    Badri, Dayakar V.; Quintana, Naira; El Kassis, Elie G.; Kim, Hye Kyong; Choi, Young Hae; Sugiyama, Akifumi; Verpoorte, Robert; Martinoia, Enrico; Manter, Daniel K.; Vivanco, Jorge M.

    2009-01-01

    Root exudates influence the surrounding soil microbial community, and recent evidence demonstrates the involvement of ATP-binding cassette (ABC) transporters in root secretion of phytochemicals. In this study, we examined effects of seven Arabidopsis (Arabidopsis thaliana) ABC transporter mutants on the microbial community in native soils. After two generations, only the Arabidopsis abcg30 (Atpdr2) mutant had significantly altered both the fungal and bacterial communities compared with the wild type using automated ribosomal intergenic spacer analysis. Similarly, root exudate profiles differed between the mutants; however, the largest variance from the wild type (Columbia-0) was observed in abcg30, which showed increased phenolics and decreased sugars. In support of this biochemical observation, whole-genome expression analyses of abcg30 roots revealed that some genes involved in biosynthesis and transport of secondary metabolites were up-regulated, while some sugar transporters were down-regulated compared with genome expression in wild-type roots. Microbial taxa associated with Columbia-0 and abcg30 cultured soils determined by pyrosequencing revealed that exudates from abcg30 cultivated a microbial community with a relatively greater abundance of potentially beneficial bacteria (i.e. plant-growth-promoting rhizobacteria and nitrogen fixers) and were specifically enriched in bacteria involved in heavy metal remediation. In summary, we report how a single gene mutation from a functional plant mutant influences the surrounding community of soil organisms, showing that genes are not only important for intrinsic plant physiology but also for the interactions with the surrounding community of organisms as well. PMID:19854857

  4. Artificial Root Exudate System (ARES): a field approach to simulate tree root exudation in soils

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    Lopez-Sangil, Luis; Estradera-Gumbau, Eduard; George, Charles; Sayer, Emma

    2016-04-01

    The exudation of labile solutes by fine roots represents an important strategy for plants to promote soil nutrient availability in terrestrial ecosystems. Compounds exuded by roots (mainly sugars, carboxylic and amino acids) provide energy to soil microbes, thus priming the mineralization of soil organic matter (SOM) and the consequent release of inorganic nutrients into the rhizosphere. Studies in several forest ecosystems suggest that tree root exudates represent 1 to 10% of the total photoassimilated C, with exudation rates increasing markedly under elevated CO2 scenarios. Despite their importance in ecosystem functioning, we know little about how tree root exudation affect soil carbon dynamics in situ. This is mainly because there has been no viable method to experimentally control inputs of root exudates at field scale. Here, I present a method to apply artificial root exudates below the soil surface in small field plots. The artificial root exudate system (ARES) consists of a water container with a mixture of labile carbon solutes (mimicking tree root exudate rates and composition), which feeds a system of drip-tips covering an area of 1 m2. The tips are evenly distributed every 20 cm and inserted 4-cm into the soil with minimal disturbance. The system is regulated by a mechanical timer, such that artificial root exudate solution can be applied at frequent, regular daily intervals. We tested ARES from April to September 2015 (growing season) within a leaf-litter manipulation experiment ongoing in temperate deciduous woodland in the UK. Soil respiration was measured monthly, and soil samples were taken at the end of the growing season for PLFA, enzymatic activity and nutrient analyses. First results show a very rapid mineralization of the root exudate compounds and, interestingly, long-term increases in SOM respiration, with negligible effects on soil moisture levels. Large positive priming effects (2.5-fold increase in soil respiration during the growing

  5. Transcriptomic profiling of Bacillus amyloliquefaciens FZB42 in response to maize root exudates

    LENUS (Irish Health Repository)

    Fan, Ben

    2012-06-21

    AbstractBackgroundPlant root exudates have been shown to play an important role in mediating interactions between plant growth-promoting rhizobacteria (PGPR) and their host plants. Most investigations were performed on Gram-negative rhizobacteria, while much less is known about Gram-positive rhizobacteria. To elucidate early responses of PGPR to root exudates, we investigated changes in the transcriptome of a Gram-positive PGPR to plant root exudates.ResultsBacillus amyloliquefaciens FZB42 is a well-studied Gram-positive PGPR. To obtain a comprehensive overview of FZB42 gene expression in response to maize root exudates, microarray experiments were performed. A total of 302 genes representing 8.2% of the FZB42 transcriptome showed significantly altered expression levels in the presence of root exudates. The majority of the genes (261) was up-regulated after incubation of FZB42 with root exudates, whereas only 41 genes were down-regulated. Several groups of the genes which were strongly induced by the root exudates are involved in metabolic pathways relating to nutrient utilization, bacterial chemotaxis and motility, and non-ribosomal synthesis of antimicrobial peptides and polyketides.ConclusionsHere we present a transcriptome analysis of the root-colonizing bacterium Bacillus amyloliquefaciens FZB42 in response to maize root exudates. The 302 genes identified as being differentially transcribed are proposed to be involved in interactions of Gram-positive bacteria with plants.

  6. Transcriptomic profiling of Bacillus amyloliquefaciens FZB42 in response to maize root exudates

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    Fan Ben

    2012-06-01

    Full Text Available Abstract Background Plant root exudates have been shown to play an important role in mediating interactions between plant growth-promoting rhizobacteria (PGPR and their host plants. Most investigations were performed on Gram-negative rhizobacteria, while much less is known about Gram-positive rhizobacteria. To elucidate early responses of PGPR to root exudates, we investigated changes in the transcriptome of a Gram-positive PGPR to plant root exudates. Results Bacillus amyloliquefaciens FZB42 is a well-studied Gram-positive PGPR. To obtain a comprehensive overview of FZB42 gene expression in response to maize root exudates, microarray experiments were performed. A total of 302 genes representing 8.2% of the FZB42 transcriptome showed significantly altered expression levels in the presence of root exudates. The majority of the genes (261 was up-regulated after incubation of FZB42 with root exudates, whereas only 41 genes were down-regulated. Several groups of the genes which were strongly induced by the root exudates are involved in metabolic pathways relating to nutrient utilization, bacterial chemotaxis and motility, and non-ribosomal synthesis of antimicrobial peptides and polyketides. Conclusions Here we present a transcriptome analysis of the root-colonizing bacterium Bacillus amyloliquefaciens FZB42 in response to maize root exudates. The 302 genes identified as being differentially transcribed are proposed to be involved in interactions of Gram-positive bacteria with plants.

  7. Identifying root exudates in field contaminated soil systems

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    Rosenfeld, C.; Martinez, C. E.

    2012-12-01

    Carbon (C) compounds exuded from plant roots comprise a significant and reactive fraction of belowground C pools. These exudates substantially alter the soil directly surrounding plant roots and play a vital role in the global C cycle, soil ecology, and ecosystem mobility of both nutrients and contaminants. In soils, the solubility and bioavailability of metals such as iron, zinc, and cadmium are intricately linked to the quantity and chemical characteristics of the C compounds allocated to the soil by plants. Cadmium (Cd), a toxic heavy metal, forms stronger bonds with reduced S- and N-containing compounds than with carboxylic acids, which may influence exudate composition in hyperaccumulator and tolerant plants grown in Cd contaminated soils. We hypothesize that hyperaccumulator plants will exude a larger quantity of aromatic N and chelating di- and tri-carboxylic acid molecules, while plants that exclude heavy metals from uptake will exude a larger proportion of reduced S containing molecules. This study examines how a variety of techniques can measure the low concentrations of complex organic mixtures exuded by hyperaccumulator and non-hyperaccumulator plants grown in Cd-contaminated soils. Two congeneric plants, Thlaspi caerulescens (Ganges ecotype), and T. caerulescens (Prayon ecotype) were grown in 0.5 kg pots filled with Cd-contaminated field soils from Chicago, IL. Field soils were contaminated as a result of the application of contaminated biosolids in the 1960's and 1970's. Pots were fitted for rhizon soil moisture samplers, micro-lysimeters developed for in situ collection of small volumes in unsaturated soils, prior to planting. Plants were grown for 8 weeks before exudate collection. After the 8 weeks of growth, a pulse-chase isotope tracer method using the C stable isotope, 13C, was employed to differentiate plant-derived compounds from background soil and microbial-derived compounds. Plants were placed in a CO2 impermeable chamber, and the soil

  8. Effects of Tomato Root Exudates on Meloidogyne incognita.

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    Yang, Guodong; Zhou, Baoli; Zhang, Xinyu; Zhang, Zijun; Wu, Yuanyuan; Zhang, Yiming; Lü, Shuwen; Zou, Qingdao; Gao, Yuan; Teng, Long

    2016-01-01

    Plant root exudates affect root-knot nematodes egg hatch. Chemicals in root exudates can attract nematodes to the roots or result in repellence, motility inhibition or even death. However, until recently little was known about the relationship between tomato root exudates chemicals and root-knot nematodes. In this study, root exudates were extracted from three tomato rootstocks with varying levels of nematode resistance: Baliya (highly resistant, HR), RS2 (moderately resistant, MR) and L-402 (highly susceptible, T). The effects of the root exudates on Meloidogyne incognita (M. incognita) egg hatch, survival and chemotaxis of second-stage juveniles (J2) were explored. The composition of the root exudates was analysed by gas chromatography/mass spectrometry (GC/MS) prior to and following M. incognita inoculation. Four compounds in root exudates were selected for further analysis and their allopathic effect on M. incognita were investigated. Root exudates from each tomato rootstocks (HR, MR and T strains) suppressed M. incognita egg hatch and increased J2 mortality, with the highest rate being observed in the exudates from the HR plants. Exudate from HR variety also repelled M. incognita J2 while that of the susceptible plant, T, was demonstrated to be attractive. The relative amount of esters and phenol compounds in root exudates from HR and MR tomato rootstocks increased notably after inoculation. Four compounds, 2,6-Di-tert-butyl-p-cresol, L-ascorbyl 2,6-dipalmitate, dibutyl phthalate and dimethyl phthalate increased significantly after inoculation. The egg hatch of M. incognita was suppressed by each of the compound. L-ascorbyl 2,6-dipalmitate showed the most notable effect in a concentration-dependent manner. All four compounds were associated with increased J2 mortality. The greatest effect was observed with dimethyl phthalate at 2 mmol·L-1. Dibutyl phthalate was the only compound observed to repel M. incognita J2 with no effect being detected in the other

  9. Effects of Tomato Root Exudates on Meloidogyne incognita.

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    Guodong Yang

    Full Text Available Plant root exudates affect root-knot nematodes egg hatch. Chemicals in root exudates can attract nematodes to the roots or result in repellence, motility inhibition or even death. However, until recently little was known about the relationship between tomato root exudates chemicals and root-knot nematodes. In this study, root exudates were extracted from three tomato rootstocks with varying levels of nematode resistance: Baliya (highly resistant, HR, RS2 (moderately resistant, MR and L-402 (highly susceptible, T. The effects of the root exudates on Meloidogyne incognita (M. incognita egg hatch, survival and chemotaxis of second-stage juveniles (J2 were explored. The composition of the root exudates was analysed by gas chromatography/mass spectrometry (GC/MS prior to and following M. incognita inoculation. Four compounds in root exudates were selected for further analysis and their allopathic effect on M. incognita were investigated. Root exudates from each tomato rootstocks (HR, MR and T strains suppressed M. incognita egg hatch and increased J2 mortality, with the highest rate being observed in the exudates from the HR plants. Exudate from HR variety also repelled M. incognita J2 while that of the susceptible plant, T, was demonstrated to be attractive. The relative amount of esters and phenol compounds in root exudates from HR and MR tomato rootstocks increased notably after inoculation. Four compounds, 2,6-Di-tert-butyl-p-cresol, L-ascorbyl 2,6-dipalmitate, dibutyl phthalate and dimethyl phthalate increased significantly after inoculation. The egg hatch of M. incognita was suppressed by each of the compound. L-ascorbyl 2,6-dipalmitate showed the most notable effect in a concentration-dependent manner. All four compounds were associated with increased J2 mortality. The greatest effect was observed with dimethyl phthalate at 2 mmol·L-1. Dibutyl phthalate was the only compound observed to repel M. incognita J2 with no effect being detected in

  10. Mineral protection of soil carbon counteracted by root exudates

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    Keiluweit, Marco; Bougoure, Jeremy J.; Nico, Peter S.; Pett-Ridge, Jennifer; Weber, Peter K.; Kleber, Markus

    2015-06-01

    Multiple lines of existing evidence suggest that climate change enhances root exudation of organic compounds into soils. Recent experimental studies show that increased exudate inputs may cause a net loss of soil carbon. This stimulation of microbial carbon mineralization (`priming’) is commonly rationalized by the assumption that exudates provide a readily bioavailable supply of energy for the decomposition of native soil carbon (co-metabolism). Here we show that an alternate mechanism can cause carbon loss of equal or greater magnitude. We find that a common root exudate, oxalic acid, promotes carbon loss by liberating organic compounds from protective associations with minerals. By enhancing microbial access to previously mineral-protected compounds, this indirect mechanism accelerated carbon loss more than simply increasing the supply of energetically more favourable substrates. Our results provide insights into the coupled biotic-abiotic mechanisms underlying the `priming’ phenomenon and challenge the assumption that mineral-associated carbon is protected from microbial cycling over millennial timescales.

  11. Root exudation of phytosiderophores from soil-grown wheat

    OpenAIRE

    Oburger, Eva; Gruber, Barbara; Schindlegger, Yvonne; Schenkeveld, Walter D C; Hann, Stephan; Kraemer, Stephan M; Wenzel, Walter W.; Puschenreiter, Markus

    2014-01-01

    For the first time, phytosiderophore (PS) release of wheat (Triticum aestivum cv Tamaro) grown on a calcareous soil was repeatedly and nondestructively sampled using rhizoboxes combined with a recently developed root exudate collecting tool. As in nutrient solution culture, we observed a distinct diurnal release rhythm; however, the measured PS efflux was c. 50 times lower than PS exudation from the same cultivar grown in zero iron (Fe)-hydroponic culture. Phytosiderophore rhizosphere soil so...

  12. Profiling of secondary metabolites in root exudates of Arabidopsis thaliana.

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    Strehmel, Nadine; Böttcher, Christoph; Schmidt, Stephan; Scheel, Dierk

    2014-12-01

    To explore the chemical composition of root exudates of the model plant Arabidopsis thaliana a workflow for nontargeted metabolite profiling of the semipolar fraction of root exudates was developed. It comprises hydroponic plant cultivation and sampling of root exudates under sterile conditions, sample preparation by solid-phase extraction and analysis by reversed-phase UPLC/ESI-QTOFMS. Following the established workflow, root exudates of six-week-old plants were profiled and a set of reproducibly occurring molecular features was compiled. To structurally elucidate the corresponding metabolites, accurate mass tandem mass spectrometry and on-line hydrogen/deuterium exchange were applied. Currently, a total of 103 compounds were detected and annotated by elemental composition of which more than 90 were structurally characterized or classified. Among them, 42 compounds were rigorously identified using an authenticated standard. The compounds identified so far include nucleosides, deoxynucleosides, aromatic amino acids, anabolites and catabolites of glucosinolates, dipeptides, indolics, salicylic and jasmonic acid catabolites, coumarins, mono-, di- and trilignols, hydroxycinnamic acid derivatives and oxylipins and exemplify the high chemical diversity of plant root exudates. PMID:25457500

  13. Mapping Soil Carbon from Cradle to Grave: C Transformations of Root Exudates and Plant Litter

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    Pett-Ridge, J.; Keiluweit, M.; Nuccio, E.; Bougoure, J.; Weber, P. K.; Brodie, E.; Mayali, X.; Shi, S.; Hwang, M.; Thelen, M.; Firestone, M.; Kleber, M.; Nico, P. S.

    2013-12-01

    Carbon cycling in the rhizosphere is a nexus of biophysical interactions between plant roots, microorganisms, and the soil organo-mineral matrix. Plant roots provide 30-40% of soil organic C inputs, accelerate the rate of organic matter mineralization by ~10X, and support an active microhabitat for microbial transformation of soil C. Our research on how roots influence decomposition of soil organic matter in both simplified and complex microcosms uses geochemical characterization, molecular microbiology, isotope tracing, metabolomics and novel imaging approaches (';ChipSIP' and ';STXM-SIMS') to trace the fate of isotopically labelled root exudates and plant tissues. Our previous work suggests root exudates drive O2 limitation, alter metal chemistry and mineralogy, and influence the availability of SOM. Our most recent experiments using synthetic rhizospheres were designed to identify the role of root exudates on ligno-cellulose decomposition in soils. Cultures of 13C/15N-labeled single plant cells (lignin-rich tracheary elements) were added to rhizosphere microcosm soils, and their decomposition followed under the influence of different root exudates using the dual imaging approach ';STXM-SIMS'. Using this combination of X-ray spectromicroscopy and NanoSIMS, we imaged the deconstruction of 13C/15N-labeled ligno-cellulose in situ, and mapped associations of plant cell-derived decomposition products with specific soil minerals. We've also looked at microbial community function in the more complex rhizospheres surrounding roots of the annual grass Avena fatua. Using an isotope array that allows us to follow root C into bacterial, fungal, and microfaunal communities, we tracked the movement of 13C from labeled exudates and 15N from labeled root litter into the soil microbial community. Our results indicate that the microbial communities involved in litter decomposition differ in rhizosphere versus bulk soils, which may have implications for carbon stabilization in soil.

  14. Microbial Products Trigger Amino Acid Exudation from Plant Roots1

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    Phillips, Donald A.; Fox, Tama C.; King, Maria D.; Bhuvaneswari, T.V.; Teuber, Larry R.

    2004-01-01

    Plants naturally cycle amino acids across root cell plasma membranes, and any net efflux is termed exudation. The dominant ecological view is that microorganisms and roots passively compete for amino acids in the soil solution, yet the innate capacity of roots to recover amino acids present in ecologically relevant concentrations is unknown. We find that, in the absence of culturable microorganisms, the influx rates of 16 amino acids (each supplied at 2.5 μm) exceed efflux rates by 5% to 545% in roots of alfalfa (Medicago sativa), Medicago truncatula, maize (Zea mays), and wheat (Triticum aestivum). Several microbial products, which are produced by common soil microorganisms such as Pseudomonas bacteria and Fusarium fungi, significantly enhanced the net efflux (i.e. exudation) of amino acids from roots of these four plant species. In alfalfa, treating roots with 200 μm phenazine, 2,4-diacetylphloroglucinol, or zearalenone increased total net efflux of 16 amino acids 200% to 2,600% in 3 h. Data from 15N tests suggest that 2,4-diacetylphloroglucinol blocks amino acid uptake, whereas zearalenone enhances efflux. Thus, amino acid exudation under normal conditions is a phenomenon that probably reflects both active manipulation and passive uptake by microorganisms, as well as diffusion and adsorption to soil, all of which help overcome the innate capacity of plant roots to reabsorb amino acids. The importance of identifying potential enhancers of root exudation lies in understanding that such compounds may represent regulatory linkages between the larger soil food web and the internal carbon metabolism of the plant. PMID:15347793

  15. Molecular responses in root-associative rhizospheric bacteria to variations in plant exudates

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    Abdoun, Hamid; McMillan, Mary; Pereg, Lily

    2015-04-01

    Plant exudates are a major factor in the interface of plant-soil-microbe interactions and it is well documented that the microbial community structure in the rhizosphere is largely influenced by the particular exudates excreted by various plants. Azospirillum brasilense is a plant growth promoting rhizobacterium that is known to interact with a large number of plants, including important food crops. The regulatory gene flcA has an important role in this interaction as it controls morphological differentiation of the bacterium that is essential for attachment to root surfaces. Being a response regulatory gene, flcA mediates the response of the bacterial cell to signals from the surrounding rhizosphere. This makes this regulatory gene a good candidate for analysis of the response of bacteria to rhizospheric alterations, in this case, variations in root exudates. We will report on our studies on the response of Azospirillum, an ecologically, scientifically and agriculturally important bacterial genus, to variations in the rhizosphere.

  16. A review of the influence of root-associating fungi and root exudates on the success of invasive plants

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    Cindy Bongard

    2012-08-01

    Full Text Available Plant-fungal interactions are essential for understanding the distribution and abundance of plants species. Recently, arbuscular mycorrhizal fungal (AMF partners of non-indigenous invasive plants have been hypothesized to be a critical factor influencing the invasion processes. AMF are known to improve nutrient and moisture uptake, as well as disrupt parasitic and pathogenic microbes in the host plant. Such benefits may enable invaders to establish significant and persistent populations in environments previously dominated by natives. Coupling these findings with studies on invader pathogen-disrupting root exudates is not well documented in the literature describing plant invasion strategies. The interaction effects of altered AMF associations and the impact of invader root exudates would be more relevant than understanding the AMF dynamics or the phytochemistry of successful invaders in isolation, particularly given that AMF and root exudates can have a similar role in pathogen control but function quite differently. One means to achieve this goal is to assess these strategies concurrently by characterizing both the general (mostly pathogens or commensals and AM-specific fungal colonization patterns found in field collected root samples of successful invaders, native plants growing within dense patches of invaders, and native plants growing separately from invaders. In this review I examine the emerging evidence of the ways in which AMF-plant interactions and the production of defensive root exudates provide pathways to invasive plant establishment and expansion, and conclude that interaction studies must be pursued to achieve a more comprehensive understanding of successful plant invasion.

  17. Root Exudation: The Ecological Driver of Hydrocarbon Rhizoremediation

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    Fanny Rohrbacher

    2016-03-01

    Full Text Available Rhizoremediation is a bioremediation technique whereby microbial degradation of organic contaminants occurs in the rhizosphere. It is considered to be an effective and affordable “green technology” for remediating soils contaminated with petroleum hydrocarbons. Root exudation of a wide variety of compounds (organic, amino and fatty acids, carbohydrates, vitamins, nucleotides, phenolic compounds, polysaccharides and proteins provide better nutrient uptake for the rhizosphere microbiome. It is thought to be one of the predominant drivers of microbial communities in the rhizosphere and is therefore a potential key factor behind enhanced hydrocarbon biodegradation. Many of the genes responsible for bacterial adaptation in contaminated soil and the plant rhizosphere are carried by conjugative plasmids and transferred among bacteria. Because root exudates can stimulate gene transfer, conjugation in the rhizosphere is higher than in bulk soil. A better understanding of these phenomena could thus inform the development of techniques to manipulate the rhizosphere microbiome in ways that improve hydrocarbon bioremediation.

  18. Citramalic acid and salicylic acid in sugar beet root exudates solubilize soil phosphorus

    OpenAIRE

    Karlovsky Petr; Steingrobe Bernd; Ratzinger Astrid; Hettwer Ursula; Khorassani Reza; Claassen Norbert

    2011-01-01

    Abstract Background In soils with a low phosphorus (P) supply, sugar beet is known to intake more P than other species such as maize, wheat, or groundnut. We hypothesized that organic compounds exuded by sugar beet roots solubilize soil P and that this exudation is stimulated by P starvation. Results Root exudates were collected from plants grown in hydroponics under low- and high-P availability. Exudate components were separated by HPLC, ionized by electrospray, and detected by mass spectrom...

  19. Root exudation of phytosiderophores from soil-grown wheat.

    Science.gov (United States)

    Oburger, Eva; Gruber, Barbara; Schindlegger, Yvonne; Schenkeveld, Walter D C; Hann, Stephan; Kraemer, Stephan M; Wenzel, Walter W; Puschenreiter, Markus

    2014-09-01

    For the first time, phytosiderophore (PS) release of wheat (Triticum aestivum cv Tamaro) grown on a calcareous soil was repeatedly and nondestructively sampled using rhizoboxes combined with a recently developed root exudate collecting tool. As in nutrient solution culture, we observed a distinct diurnal release rhythm; however, the measured PS efflux was c. 50 times lower than PS exudation from the same cultivar grown in zero iron (Fe)-hydroponic culture. Phytosiderophore rhizosphere soil solution concentrations and PS release of the Tamaro cultivar were soil-dependent, suggesting complex interactions of soil characteristics (salinity, trace metal availability) and the physiological status of the plant and the related regulation (amount and timing) of PS release. Our results demonstrate that carbon and energy investment into Fe acquisition under natural growth conditions is significantly smaller than previously derived from zero Fe-hydroponic studies. Based on experimental data, we calculated that during the investigated period (21-47 d after germination), PS release initially exceeded Fe plant uptake 10-fold, but significantly declined after c. 5 wk after germination. Phytosiderophore exudation observed under natural growth conditions is a prerequisite for a more accurate and realistic assessment of Fe mobilization processes in the rhizosphere using both experimental and modeling approaches. PMID:24890330

  20. Use of Rhizosphere Metabolomics to Investigate Exudation of Phenolics by Arabidopsis Roots

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    Lee, Yong Jian; Rai, Amit; Reuben, Sheela; Nesati, Victor; Almeida, Reinaldo; Swarup, Sanjay

    2013-04-01

    The rhizosphere is a specialised micro-niche for bacteria that have an active exchange of signals and nutrients with the host plant. Nearly 20% of photosynthates are released as root exudates, which consist of primary metabolites and products of secondary metabolism which are largely phenolic in nature. Previously, using rhizosphere metabolomics, we showed that nearly 50% of organic carbon in the exudates is in the form of phenolic compounds, of which the largest fraction is from the phenylpropanoid synthesis pathway. Using Arabidopsis as a model, we have demonstrated that a biased rhizosphere can be created using plants with varying levels of phenylpropanoids due to mutations in the biosynthetic or regulatory genes. These phenylpropanoids levels are reflected in the exudates, and exudates from lines with regulatory gene mutations, tt8 and ttg, have higher levels of phenylpropanoids, whereas biosynthetic mutant line, tt4, has very low and undetectable levels of phenylpropanoids. The biased rhizosphere of tt8 and ttg lines provides a nutritional advantage to rhizobacteria that can utilize these phenylpropanoids such as quercetin. With such a strategy to increase the competitiveness of plant growth-promoting rhizobacteria (PGPR) such as Pseudomonas putida, this system can be applied to improve plant performance. In order to better understand the metabolic basis of the nutritional advantage behind the competitiveness of the favoured P. putida, we elucidated its quercetin utilization pathway. We have recently cloned the gene for quercetin oxidoreductase (QuoA) and expressed it in transgenic Arabidopsis lines to alter the plant phenylpropanoid metabolism, using a gain of function approach. Since phenylpropanoid biosynthesis in plants involve formation of quercetin from naringenin, we envisaged that QuoA expression in plants will provide us with a genetic tool to "reverse" this biosynthetic step. This perturbation led to a decrease in flavonoids and an increase in lignin

  1. The effects of cotton root exudates on the growth and development of Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    Yuxiang WU; Weiping FANG; Shuijin ZHU; Kuiying JIN; Daofan JI

    2008-01-01

    The effects of upland cotton root exudates on the growth and development of Verticillium dahliae were studied, through the compared analysis of the root exudates components between the resistant and suscept-ive cotton materials, using a pair of resistant and sus-ceptive isogenic lines to Verticillium wilt, Z5629 and Z421, as well as 4 other upland cotton cultivars with different resistant levels of Verticillium wilt. The results showed that the amino acids in the root exudates of the resistant cultivars were much less than that of the sus-ceptible ones. Compared with the susceptible ones, there were a lack of aspartic acid, threonine, glutamic acid, alanine, isoleucine, leucine, phenylalanine, lysine and proline in the root exudates from the resistant cul-tivars. On the contrary, arginine was lacking in the sus-ceptive cultivars. The saccharide types in the root exudates were no different between the two kinds of cultivars, but the contents of glucose, fructose and suc-rose in the root exudates of the susceptible varieties were much higher than those in the resistant ones. The experiment of Verticillium dahliae culture showed that the cotton root exudates from resistant cultivars can effectively restrain the spore germination and mycelium growth of Verticillium dahliae, and the argi-nine was the leading amino acid in this inhibitory action, besides the nutrition of the root exudates. However, the cotton root exudates from the susceptive cotton cultivars can improve the growth and develop-ment of Verticillium dahliae effectively; among the amino acid in the exudates, alanine was the most active one in this stimulating function.

  2. Interaction of root exudates with the mineral soil constituents and their effect on mineral weathering

    Science.gov (United States)

    Mimmo, T.; Terzano, R.; Medici, L.; Lettino, A.; Fiore, S.; Tomasi, N.; Pinton, R.; Cesco, S.

    2012-04-01

    Plants release significant amounts of high and low molecular weight organic compounds into the rhizosphere. Among these exudates organic acids (e.g. citric acid, malic acid, oxalic acid), phenolic compounds (e.g. flavonoids), amino acids and siderophores of microbial and/or plant origin strongly influence and modify the biogeochemical cycles of several elements, thus causing changes in their availability for plant nutrition. One class of these elements is composed by the trace elements; some of them are essential for plants even if in small concentrations and are considered micronutrients, such as Fe, Zn, Mn. Their solubility and bioavailability can be influenced, among other factors, by the presence in soil solution of low molecular weight root exudates acting as organic complexing agents that can contribute to the mineral weathering and therefore, to their mobilization in the soil solution. The mobilized elements, in function of the element and of its concentration, can be either important nutrients or toxic elements for plants. The objective of this study was to assess the influence of several root exudates (citric acid, malic acid, oxalic acid, genistein, quercetin and siderophores) on the mineralogy of two different soils (an agricultural calcareous soil and an acidic polluted soil) and to evaluate possible synergic or competitive behaviors. X-ray diffraction (XRD) coupled with Electron Probe Micro Analysis (EPMA) was used to identify the crystalline and amorphous phases which were subjected to mineral alteration when exposed to the action of root exudates. Solubilization of trace metals such as Cu, Zn, Ni, Cr, Pb, Cd as well as of major elements such as Si, Al, Fe and Mn was assessed by means of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Soil microorganisms have proven to decrease mineral weathering by reducing the concentration of active root exudates in solution. Results obtained are an important cornerstone to better understand the

  3. Differential metabolic responses of Beauveria bassiana cultured in pupae extracts, root exudates and its interactions with insect and plant.

    Science.gov (United States)

    Luo, Feifei; Wang, Qian; Yin, Chunlin; Ge, Yinglu; Hu, Fenglin; Huang, Bo; Zhou, Hong; Bao, Guanhu; Wang, Bin; Lu, Ruili; Li, Zengzhi

    2015-09-01

    Beauveria bassiana is a kind of world-wide entomopathogenic fungus and can also colonize plant rhizosphere. Previous researches showed differential expression of genes when entomopathogenic fungi are cultured in insect or plant materials. However, so far there is no report on metabolic alterations of B. bassiana in the environments of insect or plant. The purpose of this paper is to address this problem. Herein, we first provide the metabolomic analysis of B. bassiana cultured in insect pupae extracts (derived from Euproctis pseudoconspersa and Bombyx mori, EPP and BMP), plant root exudates (derived from asparagus and carrot, ARE and CRE), distilled water and minimal media (MM), respectively. Principal components analysis (PCA) shows that mycelia cultured in pupae extracts and root exudates are evidently separated and individually separated from MM, which indicates that fungus accommodates to insect and plant environments by different metabolic regulation mechanisms. Subsequently, orthogonal projection on latent structure-discriminant analysis (OPLS-DA) identifies differential metabolites in fungus under three environments relative to MM. Hierarchical clustering analysis (HCA) is performed to cluster compounds based on biochemical relationships, showing that sphingolipids are increased in BMP but are decreased in EPP. This observation further implies that sphingolipid metabolism may be involved in the adaptation of fungus to different hosts. In the meantime, sphingolipids are significantly decreased in root exudates but they are not decreased in distilled water, suggesting that some components of the root exudates can suppress sphingolipid to down-regulate sphingolipid metabolism. Pathway analysis finds that fatty acid metabolism is maintained at high level but non-ribosomal peptides (NRP) synthesis is unaffected in mycelia cultured in pupae extracts. In contrast, fatty acid metabolism is not changed but NRP synthesis is high in mycelia cultured in root exudates

  4. Bioassay and Identification of Root Exudates of Three Fruit Tree Species

    Institute of Scientific and Technical Information of China (English)

    Jiang-Hong Zhang; Zhi-Quan Mao; Li-Qin Wang; Huai-Rui Shu

    2007-01-01

    A laboratory bioassay was designed to determine the allelopathic potential of root exudates of three fruit tree species on apple germination. The results showed that root exudates of apple (Malus pumila L.) and peach (Prunus persica L.), each at concentrations of 0.02 and 0.2 mg/L, inhibited germination and radicle growth of apple seeds by 56.7%, 60.7%, 51.5%, and 59.3%, respectively. The corresponding shoot growth inhibition rate was 49.5%, 46.7%, 36.4%, and 44%, respectively. Root exudates of jujube (Ziziphus jujuba Mill.) had no significant effect on apple seeds.Qualitative determination of root exudates of apple, peach, and jujube tree was developed with gas chromatography-mass spectrometry. The root exudates of apple seedlings mainly contain organic acids, glycol, esters, and benzenphenol derivatives. Peach root exudates contained phenolic acids and benzenphenol derivatives in addition to two unidentified compounds. The root exudates of jujube did not contain any phenolic acids.

  5. Metabolite Profiling of Root Exudates of Common Bean under Phosphorus Deficiency

    Directory of Open Access Journals (Sweden)

    Keitaro Tawaraya

    2014-07-01

    Full Text Available Root exudates improve the nutrient acquisition of plants and affect rhizosphere microbial communities. The plant nutrient status affects the composition of root exudates. The purpose of this study was to examine common bean (Phaseolus vulgaris L. root exudates under phosphorus (P deficiency using a metabolite profiling technique. Common bean plants were grown in a culture solution at P concentrations of 0 (P0, 1 (P1 and 8 (P8 mg P L−1 for 1, 10 and 20 days after transplanting (DAT. Root exudates were collected, and their metabolites were determined by capillary electrophoresis time-of-flight mass spectrometry (CE-TOF MS. The shoot P concentration and dry weight of common bean plants grown at P0 were lower than those grown at P8. One hundred and fifty-nine, 203 and 212 metabolites were identified in the root exudates, and 16% (26/159, 13% (26/203 and 9% (20/212 of metabolites showed a P0/P8 ratio higher than 2.0 at 1, 10 and 20 DAT, respectively. The relative peak areas of several metabolites, including organic acids and amino acids, in root exudates were higher at P0 than at P8. These results suggest that more than 10% of primary and secondary metabolites are induced to exude from roots of common bean by P deficiency.

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

    Science.gov (United States)

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

    2015-01-01

    Inputs of low molecular weight carbon (LMW-C) to soil - primarily via root exudates- are expected to be a major driver of microbial activity and source of stable soil organic carbon. It is expected that variation in the type and composition of LMW-C entering soil will influence microbial community composition and function. If this is the case then short-term changes in LMW-C inputs may alter processes regulated by these communities. To determine if change in the composition of LMW-C inputs influences microbial community function and composition, we conducted a 90 day microcosm experiment whereby soils sourced from three different land covers (meadows, deciduous forests, and white pine stands) were amended, at low concentrations, with one of eight simulated root exudate treatments. Treatments included no addition of LMW-C, and the full factorial combination of glucose, glycine, and oxalic acid. After 90 days, we conducted a functional response assay and determined microbial composition via phospholipid fatty acid analysis. Whereas we noted a statistically significant effect of exudate treatments, this only accounted for ∼3% of the variation observed in function. In comparison, land cover and site explained ∼46 and ∼41% of the variation, respectively. This suggests that exudate composition has little influence on function compared to site/land cover specific factors. Supporting the finding that exudate effects were minor, we found that an absence of LMW-C elicited the greatest difference in function compared to those treatments receiving any LMW-C. Additionally, exudate treatments did not alter microbial community composition and observable differences were instead due to land cover. These results confirm the strong effects of land cover/site legacies on soil microbial communities. In contrast, short-term changes in exudate composition, at meaningful concentrations, may have little impact on microbial function and composition. PMID:26322029

  7. Overexpression of a Foreign Bt Gene in Cotton Affects the Low-Molecular-Weight Components in Root Exudates

    Institute of Scientific and Technical Information of China (English)

    YAN Wei-Dong; SHI Wei-Ming; LI Bao-Hai; ZHANG Min

    2007-01-01

    Most research in the past using genetically modified crops (GM crops) has focused on the ecological safety of foreign gene (i.e., the gene flow), gene products (for example, Bt (Bacillus thuringiensis) protein), and the safety of transgenic food for humans. In this study, changes in both the species and amounts of low-molecular-weight components in cotton (Gossypium hirsutum L.) root exudates after foreign Bt gene overexpression were investigated under different nutritional conditions. Transgenic cotton containing Bt (Bt-cotton), supplemented with all the mineral nutrients, secreted more organic acids than the wild-type cotton (WT). When nitrogen was removed from the full-nutrient solution, the amount of organic acids secretion of Bt-cotton was lesser than that of WT. The roots of the transgenic cotton secreted lesser amounts of amino acids and soluble sugars than the WT roots in the full-nutrient solution. Deficiencies of P and K caused a large increase in the total amino acid and soluble sugar secretions of both Bt-cotton and WT, with larger increases observed in Bt-cotton. Because transferring the foreign Bt gene into cotton can result in alterations in the components of the root exudates, with the effect varying depending on the nutritional status, the cultivation of genetically modified crops, such as Bt-cotton, in soil environments should be more carefully assessed, and the possible effects as a result of the alterations in the root exudate components should be considered.

  8. The root exudation of grain amaranth and its role in release of mineral potassium

    International Nuclear Information System (INIS)

    Grain amaranth is a pseudo-cereal with big biomass and abundant mineral elements. The genotypic variations of Amaranthus spp. with different K-use efficiency (KUE) were studied in root exudation and the role of root exudate in solubilizing mineral K by use of hydroponics and 14C tracing technique. The results showed that high KUE varieties had strong ability of both CO2 assimilation and exudation of photosynthate. Predominate low-molecular-weight organic acids (IMWOAs) in root exudate of grain amaranth was oxalic acid, accounting for more than 95% of the total LMWOAs tested. Amaranthus spp. differed in the intensity of root exudation with an order as. A. dubis>A. retroflexus>A. cruentus. In the same species, then, high KUE varieties usually had higher power of excretion. K-free treatment promoted excretion of photosynthate, but oxalic acid increased only in high KUE varieties. The root exudate could solubilize K-minerals significantly, and the amount of oxalic acid and its K release were closely correlated, which indicated that oxalic acid exudation is one of the key mechanism for Amaranthus spp. to enrich and take up K from K-minerals

  9. Plant-microbe rhizosphere interactions mediated by Rehmannia glutinosa root exudates under consecutive monoculture

    Science.gov (United States)

    Wu, Linkun; Wang, Juanying; Huang, Weimin; Wu, Hongmiao; Chen, Jun; Yang, Yanqiu; Zhang, Zhongyi; Lin, Wenxiong

    2015-10-01

    Under consecutive monoculture, the biomass and quality of Rehmannia glutinosa declines significantly. Consecutive monoculture of R. glutinosa in a four-year field trial led to significant growth inhibition. Most phenolic acids in root exudates had cumulative effects over time under sterile conditions, but these effects were not observed in the rhizosphere under monoculture conditions. It suggested soil microbes might be involved in the degradation and conversion of phenolic acids from the monocultured plants. T-RFLP and qPCR analysis demonstrated differences in both soil bacterial and fungal communities during monoculture. Prolonged monoculture significantly increased levels of Fusarium oxysporum, but decreased levels of Pseudomonas spp. Abundance of beneficial Pseudomonas spp. with antagonistic activity against F. oxysporum was lower in extended monoculture soils. Phenolic acid mixture at a ratio similar to that found in the rhizosphere could promote mycelial growth, sporulation, and toxin (3-Acetyldeoxynivalenol, 15-O-Acetyl-4-deoxynivalenol) production of pathogenic F. oxysporum while inhibiting growth of the beneficial Pseudomonas sp. W12. This study demonstrates that extended monoculture can alter the microbial community of the rhizosphere, leading to relatively fewer beneficial microorganisms and relatively more pathogenic and toxin-producing microorganisms, which is mediated by the root exudates.

  10. Organic acids from root exudates of banana help root colonization of PGPR strain Bacillus amyloliquefaciens NJN-6.

    Science.gov (United States)

    Yuan, Jun; Zhang, Nan; Huang, Qiwei; Raza, Waseem; Li, Rong; Vivanco, Jorge M; Shen, Qirong

    2015-01-01

    The successful colonization of plant growth promoting rhizobacteria (PGPR) in the rhizosphere is an initial and compulsory step in the protection of plants from soil-borne pathogens. Therefore, it is necessary to evaluate the role of root exudates in the colonization of PGPR. Banana root exudates were analyzed by high pressure liquid chromatography (HPLC) which revealed exudates contained several organic acids (OAs) including oxalic, malic and fumaric acid. The chemotactic response and biofilm formation of Bacillus amyloliquefaciens NJN-6 were investigated in response to OA's found in banana root exudates. Furthermore, the transcriptional levels of genes involved in biofilm formation, yqxM and epsD, were evaluated in response to OAs via quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Results suggested that root exudates containing the OAs both induced the chemotaxis and biofilm formation in NJN-6. In fact, the strongest chemotactic and biofilm response was found when 50 μM of OAs were applied. More specifically, malic acid showed the greatest chemotactic response whereas fumaric acid significantly induced biofilm formation by a 20.7-27.3% increase and therefore biofilm formation genes expression. The results showed banana root exudates, in particular the OAs released, play a crucial role in attracting and initiating PGPR colonization on the host roots. PMID:26299781

  11. Citrate Root Exudation under Zn and P Deficiency

    OpenAIRE

    Bless Aplena Elen Siane

    2012-01-01

    Zinc and phosphorus are essential nutrients with low bioavailability in calcareous soils. Some plants exude organic acids to increase the solubility of these two nutrients. The objective of this study was to examine citrate exudation rates of different lupin (Feodora and Energy) and rapeseed (Dunkeld, Yickadee and Rainbow) cultivars underdeficiencies of Zn and P. The plants were cultivated into three different nutrient solutions (complete, -Zn, and -P)with pH around 7. Under Zn deficiency, ra...

  12. Root exudates drive interspecific facilitation by enhancing nodulation and N2 fixation.

    Science.gov (United States)

    Li, Bai; Li, Yu-Ying; Wu, Hua-Mao; Zhang, Fang-Fang; Li, Chun-Jie; Li, Xue-Xian; Lambers, Hans; Li, Long

    2016-06-01

    Plant diversity in experimental systems often enhances ecosystem productivity, but the mechanisms causing this overyielding are only partly understood. Intercropping faba beans (Vicia faba L.) and maize (Zea mays L.) result in overyielding and also, enhanced nodulation by faba beans. By using permeable and impermeable root barriers in a 2-y field experiment, we show that root-root interactions between faba bean and maize significantly increase both nodulation and symbiotic N2 fixation in intercropped faba bean. Furthermore, root exudates from maize promote faba bean nodulation, whereas root exudates from wheat and barley do not. Thus, a decline of soil nitrate concentrations caused by intercropped cereals is not the sole mechanism for maize promoting faba bean nodulation. Intercropped maize also caused a twofold increase in exudation of flavonoids (signaling compounds for rhizobia) in the systems. Roots of faba bean treated with maize root exudates exhibited an immediate 11-fold increase in the expression of chalcone-flavanone isomerase (involved in flavonoid synthesis) gene together with a significantly increased expression of genes mediating nodulation and auxin response. After 35 d, faba beans treated with maize root exudate continued to show up-regulation of key nodulation genes, such as early nodulin 93 (ENOD93), and promoted nitrogen fixation. Our results reveal a mechanism for how intercropped maize promotes nitrogen fixation of faba bean, where maize root exudates promote flavonoid synthesis in faba bean, increase nodulation, and stimulate nitrogen fixation after enhanced gene expression. These results indicate facilitative root-root interactions and provide a mechanism for a positive relationship between species diversity and ecosystem productivity. PMID:27217575

  13. Root Exudation by Aphid Leaf Infestation Recruits Root-Associated Paenibacillus spp. to Lead Plant Insect Susceptibility.

    Science.gov (United States)

    Kim, Bora; Song, Geun Cheol; Ryu, Choong-Min

    2016-03-28

    Aphids are a large group of hemipteran pests that affect the physiology, growth, and development of plants by using piercing mouthparts to consume fluids from the host. Based an recent data, aphids modulate the microbiomes of plants and thereby affect the overall outcome of the biological interaction. However, in a few reports, aboveground aphids manipulate the metabolism of the host and facilitate infestations by rhizosphere bacteria (rhizobacteria). In this study, we evaluated whether aphids alter the plant resistance that is mediated by the bacterial community of the root system. The rhizobacteria were affected by aphid infestation of pepper, and a large population of gram-positive bacteria was detected. Notably, Paenibacillus spp. were the unique gram-positive bacteria to respond to changes induced by the aphids. Paenibacillus polymyxa E681 was used as a rhizobacterium model to assess the recruitment of bacteria to the rhizosphere by the phloem-sucking of aphids and to test the effect of P. polymyxa on the susceptibility of plants to aphids. The root exudates secreted from peppers infested with aphids increased the growth rate of P. polymyxa E681. The application of P. polymyxa E681 to pepper roots promoted the colonization of aphids within 2 days of inoculation. Collectively, our results suggest that aphid infestation modulated the root exudation, which led to the recruitment of rhizobacteria that manipulated the resistance of peppers to aphids. In this study, new information is provided on how the infestation of insects is facilitated through insect-derived modulation of plant resistance with the attraction of gram-positive rhizobacteria. PMID:26699743

  14. Citramalic acid and salicylic acid in sugar beet root exudates solubilize soil phosphorus

    Directory of Open Access Journals (Sweden)

    Karlovsky Petr

    2011-08-01

    Full Text Available Abstract Background In soils with a low phosphorus (P supply, sugar beet is known to intake more P than other species such as maize, wheat, or groundnut. We hypothesized that organic compounds exuded by sugar beet roots solubilize soil P and that this exudation is stimulated by P starvation. Results Root exudates were collected from plants grown in hydroponics under low- and high-P availability. Exudate components were separated by HPLC, ionized by electrospray, and detected by mass spectrometry in the range of mass-to-charge ratio (m/z from 100 to 1000. Eight mass spectrometric signals were enhanced at least 5-fold by low P availability at all harvest times. Among these signals, negative ions with an m/z of 137 and 147 were shown to originate from salicylic acid and citramalic acid. The ability of both compounds to mobilize soil P was demonstrated by incubation of pure substances with Oxisol soil fertilized with calcium phosphate. Conclusions Root exudates of sugar beet contain salicylic acid and citramalic acid, the latter of which has rarely been detected in plants so far. Both metabolites solubilize soil P and their exudation by roots is stimulated by P deficiency. These results provide the first assignment of a biological function to citramalic acid of plant origin.

  15. Stress differentially impacts reserve pools and root exudation: implications for ecosystem functioning and carbon balance

    Science.gov (United States)

    Landhäusser, Simon; Karst, Justine; Wiley, Erin; Gaster, Jacob

    2016-04-01

    Environmental stress can influence carbon assimilation and the accumulation and distribution of carbon between growth, reserves, and exudation; however, it is unclear how these processes vary by different stress types. Partitioning of carbon to growth and reserves in plants might also vary between different organs. Roots reserves are of particular interest as they link the plant with the soil carbon cycle through exudation. Simple models of diffusion across concentration gradients predict the more C reserves in roots, the more C should be exuded from roots. However, the mechanisms underlying the accumulation and loss of C from roots may differ depending on the stress experienced by the plants. In a controlled study we tested whether different types of stresses (shade, cold soil, and drought) have differential effects on the distribution, abundance, and form (sugar vs. starch) of carbohydrates in seedlings, and whether these changes alone could explain differences in root exudation between stress types. Non-structural carbohydrate (NSC) concentration and pool sizes varied by stress type and between organs. Mass-specific C exudation increased with fine root sugar concentration; however, stress type affected exudation independently of reserve concentration. Seedlings exposed to cold soils exuded the most C on a per root mass basis followed by shade and drought. Through 13C labeling, we also found that depending on the stress type, aspen seedlings may be less able to control the loss of C to the soil compared with unstressed seedlings, resulting in more C leaked to the rhizosphere. The loss of C beyond that predicted by simple concentration gradients might have important implications for ecosystem functioning and carbon balance. If stressed plants lose proportionally more carbon to the soil, existing interactions between plants and soils may decouple under stress, and may include unexpected C fluxes between trees, soils and the atmosphere with a changing climate.

  16. Role of root exudates in dissolution of Cd containing iron oxides

    Science.gov (United States)

    Rosenfeld, C.; Martinez, C. E.

    2011-12-01

    Dissolved organic matter (DOM) in the rhizosphere contains organic acids, amino acids and more complex organic molecules that can substantially impact the solubility of soil solid phases. Plant roots and soil microorganisms contribute a large fraction of these organic compounds to DOM, potentially accelerating the transfer of solid phase elements into solution. In highly contaminated soils, heavy metals such as Cd are commonly found coprecipitated with common minerals (e.g. iron oxides). Introducing or changing vegetation on these contaminated soils may increase DOM levels in the soil pore fluids and thus enhance the biological and chemical weathering of soil minerals. Here, we investigate the role of root exudates on mineral dissolution and Cd mobility in contaminated soils. We hypothesize that plant exudates containing nitrogen and sulfur functional groups will dissolve Cd-containing mineral phases to a greater extent than exudates containing only oxygen functional groups, resulting in higher Cd concentrations in solution. Two different iron oxide mineral phases were utilized in a laboratory-scale model study system investigating the effects of low molecular weight, oxygen-, nitrogen-, and sulfur-containing organic compounds on mineral dissolution. Goethite (α-FeOOH) was synthesized in the laboratory with 0, 2.4, 5, and 100 theoretical mol% Cd, and franklinite (ZnFe2O4) was prepared with 0, 10, and 25 theoretical mol% Cd. Phase identity of all minerals was verified with X-ray diffraction (XRD). All minerals were reacted with 0.01 mM solutions containing one of four different organic ligands (oxalic acid, citric acid, histidine or cysteine) and aliquots of these solutions were sampled periodically over 40 days. Results from solution samples suggest that oxalic acid, citric acid, and histidine consistently increase mineral dissolution relative to the control (no organic compound present) while cysteine consistently inhibits dissolution relative to the control in

  17. Experimental Investigation on Role of Root Mucilage and Microbial Exudates on Soil Water Retention Dynamics

    Science.gov (United States)

    Gebrenegus, T. B.; Ghezzehei, T.

    2011-12-01

    The release of organic molecules by soil microbes and plant roots to adapt their surrounding represents a substantial portion of the energy use by these organisms. The hypothesis in this study is that the long-chain molecules and hydrophilic nature of the released organic compounds deposited on soil surfaces drastically alters the dynamism of the soil water retention curves (SWRC) of the rhizosphere relative to the bulk soil through direct effect besides the well-known indirect influence of the organic matter by modifying the soil structure and providing energy for the biogeochemical processes. The experiment was set up in such away that it suppresses the indirect effect of organic matter (OM) and rather it traces only its immediate effect on SWRC. To achieve this goal inert and uniform size (0.1-0.11 mm) glassbeads were used. We assumed that wet mixing of the glass beads with OM and slow drying the mixture (40-50oC) for 1-day will lead to deposition of the OM only at the surface of the glass beads, the short time being not enough for aggregate formation. This way we can simulate the natural deposition of OM on soil surfaces. Our argument is that this deposited OM has its own distinct time-dependent SWRC which is different from that of bulk soil. Model exudates including PGA, XA, and SPA are used to mimic the behavior of plant root mucilages, bacterial and fungal exudates respectively. These model exudates at varying concentration (0, 0.008, 0.04, and 0.2 gm/l) were wet mixed with glass beads. SWRC was determined using both water-hanging column and pressure plate for both low and high suction ranges respectively. We will present the effect of exudate type and level of concentration on the dynamic behavior of SWRC of the glassbeads by determining: i) the SWRC for each treatment; ii) the rate of drying and wetting at different intervals; iii) the hysteresis of the retention curves; iv) the saturated hydraulic conductivity.

  18. Root exudation and root development of lettuce (Lactuca sativa L.cv. Tizian as affected by different soils

    Directory of Open Access Journals (Sweden)

    GünterNeumann

    2014-01-01

    Full Text Available Development and activity of plant roots exhibits high adaptive variability. Although it is well-documented, that physicochemical soil properties can strongly influence root morphology and root exudation, particularly under field conditions, a comparative assessment is complicated by the impact of additional factors, such as climate and cropping history. To overcome these limitations, in this study, field soils originating from an unique experimental plot system with three different soil types, which were stored at the same field site for ten years and exposed to the same agricultural management practice, were used for an investigation on effects of soil type on root development and root exudation. Lettuce (Lactuca sativa L. cv. Tizian was used as a model plant, grown under controlled environmental conditions in a minirhizotrone system equipped with root observation windows (rhizoboxes. Root exudates were collected by placing sorption filters onto the root surface followed by subsequent extraction and GC-MS profiling of the trapped compounds. Surprisingly, even in absence of external stress factors with known impact on root exudation, such as pH extremes, water and nutrient limitations/toxicities or soil structure effects (use of sieved soils, root growth characteristics (root length, fine root development as well as profiles of root exudates were strongly influenced by the soil type used for plant cultivation. The results coincided well with differences in rhizosphere bacterial communities, detected in field-grown lettuce plants cultivated on the same soils (Schreiter et al., this issue. The findings suggest that the observed differences may be the result of plant interactions with the soil-specific microbiomes.

  19. EFFECT OF ROOT EXUDATES OF TAGETES SP. ON EGG HATCHING BEHAVIOR OF MELOIDOGYNE INCOGNITA

    Directory of Open Access Journals (Sweden)

    Iruthaya Kalaiselvam

    2011-10-01

    Full Text Available The effect root exudates of pre-planted marigold intercropped with tomato in regulating the hatching behavior of root-knot nematode - Meloidogyne incognita eggs were investigated. Marigold cultivars Tagetes patula, T. minuta, T. erecta, T. erecta (var. Orange, T. erecta (var. Yellow significantly reduced the numbers of second-stage juveniles (J2s in subsequent tomato compared to the tomato-tomato control. Four different concentrations (25, 50, 75 and 100 % of water soluble extract from the selected varieties of Marigold cultivars were filtered and added to the petri dish and infested with the eggs of M. incognita. Data indicate that egg hatching was significantly affected by root exudates of Tagetes sp. however, nematicidal activity was species dependent. Root exudates of T. erecta were lethal to J2 of M. incognita and were inhibitory to the hatch of eggs at the concentration of 75 % or higher.

  20. The impact of mucilage exudate on root water uptake - Numerical study

    Science.gov (United States)

    Schwartz, N.; Carminati, A.; Javaux, M.

    2015-12-01

    For many years, the rhizosphere, which is the zone of soil in the vicinity of the roots and which is influenced by the roots, is known as a unique soil environment with different physical, biological and chemical properties than those of the bulk soil. Indeed, in recent studies it has been shown that root exudates and especially mucilage alter the hydraulic properties of the soil, and that drying and wetting cycles of mucilage result in non-equilibrium water dynamics in the rhizosphere. While there are experimental evidences and simplified 1D model for those concepts, an integrated model that considers rhizosphere processes with a detailed model for water and roots flow is absent. Therefore, the objective of this work is to develop a 3D physical model of water flow in the soil-plant continuum that take in consideration root architecture and rhizosphere specific properties. We simulate wetting and drying cycles and examine the impact of various rhizosphere processes on water content distribution and root water uptake (RWU). For wetting, the model predict that after infiltration the rate of change in the rhizosphere water content is lower than in the bulk soil (due to non-equilibrium), but over time water infiltrated into the rhizosphere and eventually the water content in the rhizosphere became higher than in the bulk soil. For drying, the high water holding capacity of the rhizosphere, and the non-equilibrium between water content and water potential delay the onset of stress. Furthermore, when continues drying-wetting setup is examined, rhizosphere properties results in a lower fluctuation of the water content around the root. Overall, the model presented here is the first attempt to include rhizosphere specific processes within a detailed soil-plant water flow model. The model provides a tool to examine the impact of different rhizosphere processes on water dynamics and RWU under different irrigation practices.

  1. Root exudates of wetland plants influenced by nutrient status and types of plant cultivation.

    Science.gov (United States)

    Wu, Fu Yong; Chung, Anna King Chuen; Tam, Nora Fung Yee; Wong, Ming Hung

    2012-07-01

    The present study investigated the amounts of root exudates and composition of organic acids released from two wetland plants (Typha latifolia and Vetiver zizanioides) under two nutrient treatments: low level (0.786 mM N and 0.032 mM P) and high level (7.86 mM N and 0.32 mM P) and two types of plant cultivation: monoculture and co-culture of the two plants. Low nutrient treatment significantly (p < 0.05) increased the root exudates of T. latifolia during the initial growth period (1-21 d) and those of V. zizanioides and the co-culture during the whole growth period. The concentrations of dissolved organic carbon in the root exudates of the co-culture in the low nutrient treatment were 3.23-7.91 times of those in the high nutrient treatment during the medium growth period (7-28 d). The compositions of organic acids varied between the two plant species and between the two nutrient treatments. The pattern of organic acids was also different between the co-culture and the monoculture. Oxalic acid was by far the major organic acid exuded from the two wetland plants. The present study on root exudates suggests that co-culture of wetland plant species would be more useful in the reclamation of waste water than a monoculture system. PMID:22908625

  2. Effect of soil water content on spatial distribution of root exudates and mucilage in the rhizosphere

    Science.gov (United States)

    Holz, Maire; Zarebanadkouki, Mohsen; Kuzyakov, Yakov; Carminati, Andrea

    2016-04-01

    Water and nutrients are expected to become the major factors limiting food production. Plant roots employ various mechanisms to increase the access to these limited soil resources. Low molecular root exudates released into the rhizosphere increase nutrient availability, while mucilage improves water availability under low moisture conditions. However, studies on the spatial distribution and quantification of exudates in soil are scarce. Our aim was therefore to quantify and visualize root exudates and mucilage distribution around growing roots using neutron radiography and 14C imaging at different levels of water stress. Maize plants were grown in rhizotrons filled with a silty soil and were exposed to varying soil conditions, from optimal to dry. Mucilage distribution around the roots was estimated from the profiles of water content in the rhizosphere - note that mucilage increases the soil water content. The profiles of water content around different root types and root ages were measured with neutron radiography. Rhizosphere extension was approx. 0.7 mm and did not differ between wet and dry treatments. However, water content (i.e. mucilage concentration) in the rhizosphere of plants grown in dry soils was higher than for plants grown under optimal conditions. This effect was particularly pronounced near the tips of lateral roots. The higher water contents near the root are explained as the water retained by mucilage. 14C imaging of root after 14CO2 labeling of shoots (Pausch and Kuzyakov 2011) was used to estimate the distribution of all rhizodeposits. Two days after labelling, 14C distribution was measured using phosphor-imaging. To quantify 14C in the rhizosphere a calibration was carried out by adding given amounts of 14C-glucose to soil. Plants grown in wet soil transported a higher percentage of 14C to the roots (14Croot/14Cshoot), compared to plants grown under dry conditions (46 vs. 36 %). However, the percentage of 14C allocated from roots to

  3. Root exudation of phytochemicals in Arabidopsis follows specific patterns that are developmentally programmed and correlate with soil microbial functions.

    Directory of Open Access Journals (Sweden)

    Jacqueline M Chaparro

    Full Text Available Plant roots constantly secrete compounds into the soil to interact with neighboring organisms presumably to gain certain functional advantages at different stages of development. Accordingly, it has been hypothesized that the phytochemical composition present in the root exudates changes over the course of the lifespan of a plant. Here, root exudates of in vitro grown Arabidopsis plants were collected at different developmental stages and analyzed using GC-MS. Principle component analysis revealed that the composition of root exudates varied at each developmental stage. Cumulative secretion levels of sugars and sugar alcohols were higher in early time points and decreased through development. In contrast, the cumulative secretion levels of amino acids and phenolics increased over time. The expression in roots of genes involved in biosynthesis and transportation of compounds represented in the root exudates were consistent with patterns of root exudation. Correlation analyses were performed of the in vitro root exudation patterns with the functional capacity of the rhizosphere microbiome to metabolize these compounds at different developmental stages of Arabidopsis grown in natural soils. Pyrosequencing of rhizosphere mRNA revealed strong correlations (p<0.05 between microbial functional genes involved in the metabolism of carbohydrates, amino acids and secondary metabolites with the corresponding compounds released by the roots at particular stages of plant development. In summary, our results suggest that the root exudation process of phytochemicals follows a developmental pattern that is genetically programmed.

  4. Root Exudation of Phytochemicals in Arabidopsis Follows Specific Patterns That Are Developmentally Programmed and Correlate with Soil Microbial Functions

    Science.gov (United States)

    Sugiyama, Akifumi; Manter, Daniel K.; Vivanco, Jorge M.

    2013-01-01

    Plant roots constantly secrete compounds into the soil to interact with neighboring organisms presumably to gain certain functional advantages at different stages of development. Accordingly, it has been hypothesized that the phytochemical composition present in the root exudates changes over the course of the lifespan of a plant. Here, root exudates of in vitro grown Arabidopsis plants were collected at different developmental stages and analyzed using GC-MS. Principle component analysis revealed that the composition of root exudates varied at each developmental stage. Cumulative secretion levels of sugars and sugar alcohols were higher in early time points and decreased through development. In contrast, the cumulative secretion levels of amino acids and phenolics increased over time. The expression in roots of genes involved in biosynthesis and transportation of compounds represented in the root exudates were consistent with patterns of root exudation. Correlation analyses were performed of the in vitro root exudation patterns with the functional capacity of the rhizosphere microbiome to metabolize these compounds at different developmental stages of Arabidopsis grown in natural soils. Pyrosequencing of rhizosphere mRNA revealed strong correlations (p<0.05) between microbial functional genes involved in the metabolism of carbohydrates, amino acids and secondary metabolites with the corresponding compounds released by the roots at particular stages of plant development. In summary, our results suggest that the root exudation process of phytochemicals follows a developmental pattern that is genetically programmed. PMID:23383346

  5. Clover root exudate produces male-biased sex ratios and accelerates male metamorphic timing in wood frogs.

    Science.gov (United States)

    Lambert, Max R

    2015-12-01

    In amphibians, abnormal metamorph sex ratios and sexual development have almost exclusively been considered in response to synthetic compounds like pesticides or pharmaceuticals. However, endocrine-active plant chemicals (i.e. phytoestrogens) are commonly found in agricultural and urban waterways hosting frog populations with deviant sexual development. Yet the effects of these compounds on amphibian development remain predominantly unexplored. Legumes, like clover, are common in agricultural fields and urban yards and exude phytoestrogen mixtures from their roots. These root exudates serve important ecological functions and may also be a source of phytoestrogens in waterways. I show that clover root exudate produces male-biased sex ratios and accelerates male metamorphosis relative to females in low and intermediate doses of root exudate. My results indicate that root exudates are a potential source of contaminants impacting vertebrate development and that humans may be cultivating sexual abnormalities in wildlife by actively managing certain plant species. PMID:27019728

  6. Tall fescue cultivar and fungal endophyte combinations influence plant growth and root exudate composition.

    Science.gov (United States)

    Guo, Jingqi; McCulley, Rebecca L; McNear, David H

    2015-01-01

    Tall fescue [Lolium arundinaceum (Schreb.)] is a cool-season perennial grass used in pastures throughout the Southeastern United States. The grass can harbor a shoot-specific fungal endophyte (Epichloë coenophiala) thought to provide the plant with enhanced resistance to biotic and abiotic stresses. Because alkaloids produced by the common variety of the endophyte cause severe animal health issues, focus has been on replacing the common-toxic strain with novel varieties that do not produce the mammal-toxic alkaloids but maintain abiotic and biotic stress tolerance benefits. Little attention has been given to the influence of the plant-fungal symbiosis on rhizosphere processes. Therefore, our objective was to study the influence of this relationship on plant biomass production and root exudate composition in tall fescue cultivars PDF and 97TF1, which were either not infected with the endophyte (E-), infected with the common toxic endophyte (CTE+) strain or with one of two novel endophytes (AR542E+, AR584E+). Plants were grown sterile for 3 weeks after which plant biomass, total organic carbon, total phenolic content and detailed chemical composition of root exudates were determined. Plant biomass production and exudate phenolic and organic carbon content were influenced by endophyte status, tall fescue cultivar, and their interaction. GC-TOF MS identified 132 compounds, including lipids, carbohydrates and carboxylic acids. Cluster analysis showed that the interaction between endophyte and cultivar resulted in unique exudate profiles. This is the first detailed study to assess how endophyte infection, notably with novel endophytes, and tall fescue cultivar interact to influence root exudate composition. Our results illustrate that tall fescue cultivar and endophyte status can influence plant growth and root exudate composition, which may help explain the observed influence of this symbiosis on rhizosphere biogeochemical processes. PMID:25914697

  7. Potential of Root Exudates from Wetland Plants and Their Potential Role for Denitrification and Allelopathic Interactions

    DEFF Research Database (Denmark)

    Zhai, Xu

    chemicals to suppress the growth of native species. Phragmites australis is recognized as the most invasive species in wetland ecosystems in North America, and allelopathy has been reported to be involved in the invasion success of the introduced exotic P. australis. The composition of the root exudates may...

  8. Metabolite fingerprinting of exudates from carrot roots grown under phosphorus stress

    Science.gov (United States)

    To see if differences in the metabolite content of exudates obtained from cultured carrot roots grown in the presence and absence of phosphorus could be detected, crude samples were analyzed via Fourier Transform Ion Cyclotron Mass Spectrometry (FTMS). The highly accurate masses and elemental compo...

  9. Oxalate and root exudates enhance the desorption of p,p'-DDT from soils.

    Science.gov (United States)

    Luo, Lei; Zhang, Shuzhen; Shan, Xiao-Quan; Zhu, Yong-Guan

    2006-05-01

    The abiotic desorption of p,p'-DDT from seven Chinese soils spiked with p,p'-DDT and the effects of oxalate at 0.001-0.1M and the root exudates of maize, wheat, and ryegrass were evaluated using batch experiments. Soil organic carbon played a predominant role in the retention of DDT. Oxalate significantly increased the desorption of p,p'-DDT, with the largest increments ranging from 11% to 54% for different soils. Oxalate addition also resulted in the increased release of dissolved organic carbon and inorganic ions from soils. Root exudates had similar effects to those of oxalate. Root exudates significantly increased DDT desorption from the soils, and the general trend was similar among the plant species studied for all the soils (p > 0.05). Low molecular weight dissolved organic carbon amendments caused partial dissolution of the soil structure, such as the organo-mineral linkages, resulting in the release of organic carbon and metal ions and thus the subsequent enhanced desorption of DDT from the soils. The enhancing effects of oxalate and root exudates on DDT desorption were influenced by the contents of soil organic carbon and dissolved organic carbon in soils. PMID:16307790

  10. Natural variation of root exudates in Arabidopsis thaliana-linking metabolomic and genomic data.

    Science.gov (United States)

    Mönchgesang, Susann; Strehmel, Nadine; Schmidt, Stephan; Westphal, Lore; Taruttis, Franziska; Müller, Erik; Herklotz, Siska; Neumann, Steffen; Scheel, Dierk

    2016-01-01

    Many metabolomics studies focus on aboveground parts of the plant, while metabolism within roots and the chemical composition of the rhizosphere, as influenced by exudation, are not deeply investigated. In this study, we analysed exudate metabolic patterns of Arabidopsis thaliana and their variation in genetically diverse accessions. For this project, we used the 19 parental accessions of the Arabidopsis MAGIC collection. Plants were grown in a hydroponic system, their exudates were harvested before bolting and subjected to UPLC/ESI-QTOF-MS analysis. Metabolite profiles were analysed together with the genome sequence information. Our study uncovered distinct metabolite profiles for root exudates of the 19 accessions. Hierarchical clustering revealed similarities in the exudate metabolite profiles, which were partly reflected by the genetic distances. An association of metabolite absence with nonsense mutations was detected for the biosynthetic pathways of an indolic glucosinolate hydrolysis product, a hydroxycinnamic acid amine and a flavonoid triglycoside. Consequently, a direct link between metabolic phenotype and genotype was detected without using segregating populations. Moreover, genomics can help to identify biosynthetic enzymes in metabolomics experiments. Our study elucidates the chemical composition of the rhizosphere and its natural variation in A. thaliana, which is important for the attraction and shaping of microbial communities. PMID:27363486

  11. Stoichiometry constrains microbial response to root exudation- insights from a model and a field experiment in a temperate forest

    Directory of Open Access Journals (Sweden)

    J. E. Drake

    2013-02-01

    Full Text Available Plant roots release a wide range of chemicals into soils. This process, termed root exudation, is thought to increase the activity of microbes and the exoenzymes they synthesize, leading to accelerated rates of carbon (C mineralization and nutrient cycling in rhizosphere soils relative to bulk soils. The nitrogen (N content of microbial biomass and exoenzymes may introduce a stoichiometric constraint on the ability of microbes to effectively utilize the root exudates, particularly if the exudates are rich in C but low in N. We combined a theoretical model of microbial activity with an exudation experiment to test the hypothesis that the ability of soil microbes to utilize root exudates for the synthesis of additional biomass and exoenzymes is constrained by N availability. The field experiment simulated exudation by automatically pumping solutions of chemicals often found in root exudates ("exudate mimics" containing C alone or C in combination with N (C : N ratio of 10 through microlysimeter "root simulators" into intact forest soils in two 50-day experiments. The delivery of C-only exudate mimics increased microbial respiration but had no effect on microbial biomass or exoenzyme activities. By contrast, experimental delivery of exudate mimics containing both C and N significantly increased microbial respiration, microbial biomass, and the activity of exoenzymes that decompose low molecular weight components of soil organic matter (SOM, e.g., cellulose, amino sugars, while decreasing the activity of exoenzymes that degrade high molecular weight SOM (e.g., polyphenols, lignin. The modeling results were consistent with the experiments; simulated delivery of C-only exudates induced microbial N-limitation, which constrained the synthesis of microbial biomass and exoenzymes. Exuding N as well as C alleviated this stoichiometric constraint in the model, allowing for increased exoenzyme production, the priming of decomposition, and a net release of N

  12. Role of Root Exudates in Adaptative Reactions of Buckwheat Plants in Aluminium-acid Stress

    Directory of Open Access Journals (Sweden)

    A.E. Smirnov

    2014-03-01

    Full Text Available Aliminium toxicity is major limiting factor of crop production in acidic soils. It is known that mechanisms of toxic effects of aluminium are differing in biochemical characters, research of aluminium toxicity complicated by variety of its chemical forms and migration in soil and water ability. The root exudates qualitative composition of common buckwheat was evaluated. Organic complexing agents – oxalic acid and phenolic compounds were revealed. The role of these complexing agents in the buckwheat aluminium resistance under acidic stress, participation in processes of external and internal detoxification was shown. Spectrophometric assay revealed an increase in root secretion of oxalic acid by 2.5 times and decrease in content of phenolic compounds in root exudates solution by 3 times upon aluminium (50 µM treatment. In the meanwhile the same concentration of the metal had induced phenylalanine ammonia-lyase activity by 2 times.

  13. Organic acid exudation from the roots of Cunninghamia lanceolata and Pinus massoniana seedlings under low phosphorus stress

    Institute of Scientific and Technical Information of China (English)

    Yuanchun YU; Jian YU; Qihua SHAN; Li FANG; Defeng JIANG

    2008-01-01

    Organic acid exudation from the roots of Chinese fir (Cunninghamia lanceolata) and Masson pine (Pinus massoniana) seedlings under low phosphorus stress was studied using the solution culture method. The results revealed that organic acid exudation from the roots of Chinese fir and Masson pine seedlings under low phosphorus stress increased. Compared with P3 (KH2PO4, 0.5 mmol/L), the average organic acid exuda-tion from the root of Masson pine seedlings under P0 (KH2PO4, 0 mmol/L), P1 (KH2PO4, 0.03 mmol/L) and P2(KH2PO4, 0.09 mmol/L) increased by 328.6%, 267.9% and 126.4% respectively. Masson pine from Zhejiang Province in China had the highest organic acid exuda-tion. Under low phosphorus stress, the increase in organic acid exudation from the different provinces of Chinese fir and Masson pine varied. Masson pine from Zhejiang Province mainly increased oxalic acid, tartaric acid, citric acid and malic acid exudation, that from Guangxi Province mainly increased oxalic acid and tartaric acid exudation, and that from Guizhou Province, China mainly increased oxalic acid, tartaric acid and malic acid exudation. Chinese fir mainly increased oxalic acid and tartaric acid exudation.

  14. Contrasting responses of root morphology and root-exuded organic acids to low phosphorus availability in three important food crops with divergent root traits

    Science.gov (United States)

    Wang, Yan-Liang; Almvik, Marit; Clarke, Nicholas; Eich-Greatorex, Susanne; Øgaard, Anne Falk; Krogstad, Tore; Lambers, Hans; Clarke, Jihong Liu

    2015-01-01

    Phosphorus (P) is an important element for crop productivity and is widely applied in fertilizers. Most P fertilizers applied to land are sorbed onto soil particles, so research on improving plant uptake of less easily available P is important. In the current study, we investigated the responses in root morphology and root-exuded organic acids (OAs) to low available P (1 μM P) and sufficient P (50 μM P) in barley, canola and micropropagated seedlings of potato—three important food crops with divergent root traits, using a hydroponic plant growth system. We hypothesized that the dicots canola and tuber-producing potato and the monocot barley would respond differently under various P availabilities. WinRHIZO and liquid chromatography triple quadrupole mass spectrometry results suggested that under low P availability, canola developed longer roots and exhibited the fastest root exudation rate for citric acid. Barley showed a reduction in root length and root surface area and an increase in root-exuded malic acid under low-P conditions. Potato exuded relatively small amounts of OAs under low P, while there was a marked increase in root tips. Based on the results, we conclude that different crops show divergent morphological and physiological responses to low P availability, having evolved specific traits of root morphology and root exudation that enhance their P-uptake capacity under low-P conditions. These results could underpin future efforts to improve P uptake of the three crops that are of importance for future sustainable crop production. PMID:26286222

  15. Contrasting responses of root morphology and root-exuded organic acids to low phosphorus availability in three important food crops with divergent root traits.

    Science.gov (United States)

    Wang, Yan-Liang; Almvik, Marit; Clarke, Nicholas; Eich-Greatorex, Susanne; Øgaard, Anne Falk; Krogstad, Tore; Lambers, Hans; Clarke, Jihong Liu

    2015-01-01

    Phosphorus (P) is an important element for crop productivity and is widely applied in fertilizers. Most P fertilizers applied to land are sorbed onto soil particles, so research on improving plant uptake of less easily available P is important. In the current study, we investigated the responses in root morphology and root-exuded organic acids (OAs) to low available P (1 μM P) and sufficient P (50 μM P) in barley, canola and micropropagated seedlings of potato-three important food crops with divergent root traits, using a hydroponic plant growth system. We hypothesized that the dicots canola and tuber-producing potato and the monocot barley would respond differently under various P availabilities. WinRHIZO and liquid chromatography triple quadrupole mass spectrometry results suggested that under low P availability, canola developed longer roots and exhibited the fastest root exudation rate for citric acid. Barley showed a reduction in root length and root surface area and an increase in root-exuded malic acid under low-P conditions. Potato exuded relatively small amounts of OAs under low P, while there was a marked increase in root tips. Based on the results, we conclude that different crops show divergent morphological and physiological responses to low P availability, having evolved specific traits of root morphology and root exudation that enhance their P-uptake capacity under low-P conditions. These results could underpin future efforts to improve P uptake of the three crops that are of importance for future sustainable crop production. PMID:26286222

  16. Intraspecific variability in allelopathy of Heracleum mantegazzianum is linked to the metabolic profile of root exudates

    Czech Academy of Sciences Publication Activity Database

    Jandová, Kateřina; Dostál, Petr; Cajthaml, Tomáš; Kameník, Zdeněk

    2015-01-01

    Roč. 115, č. 5 (2015), s. 821-831. ISSN 0305-7364 R&D Projects: GA MŠk(CZ) EE2.3.30.0003; GA ČR GAP504/10/0132 Institutional support: RVO:67985939 ; RVO:61388971 Keywords : giant hogweed * root exudates * UHPLC–TOF-MS Subject RIV: EF - Botanics; EE - Microbiology, Virology (MBU-M) Impact factor: 3.654, year: 2014

  17. Effect of root exudates of different resistant varieties of cucumber on fusarium wilt and preliminary studies on their resistance mechanism

    Institute of Scientific and Technical Information of China (English)

    Benli HUANG; Yundong XU; Ye WU; Shunqi ZHANG; Xuchao CHEN

    2008-01-01

    This study investigated the effect of root exudates of cucumber varieties, Jinyan 4 (susceptible variety), Jinchun 4 (resistant variety) and Yinnan Black seed squash on fusa-rium wilt. The results showed that fusarium wilt occurrence of plants treated with the root exudate of Jinyan 4 was earlier. The infection rate was significantly higher 15 days after inoculation, but similar to the control 20 days after inocula-tion. In contrast, the infection rate of plants treated with the root exudate of Jinchun 4 was significantly lower than that of the control. The plant height and fresh weight of Jinyan 4 treated with its own root exudate were lower than those of the control, and the root vigor decreased but the conductance increased. There was no significant effect of the root exudates from Jinchun 4 and Black seed squash on plant height and fresh mass of Jinyan 4. We found that the root exudate of susceptible cucumber variety stimulated the growth of Fusarium oxysporum pathogen, in contrast, that of resistance variety and Black seed squash suppressed the growth.

  18. Effects of root exudates on the leachability, distribution, and bioavailability of phenanthrene and pyrene from mangrove sediments.

    Science.gov (United States)

    Jia, Hui; Lu, Haoliang; Liu, Jingchun; Li, Jian; Dai, Minyue; Yan, Chongling

    2016-03-01

    In this study, column leaching experiments were used to evaluate the leachability, distribution and bioavailability of phenanthrene and pyrene by root exudates from contaminated mangrove sediments. We observed that root exudates significantly promoted the release and enhanced the bioavailability of phenanthrene and pyrene from sediment columns. The concentration of phenanthrene and pyrene and cumulative content released from the analyzed sediment samples following root exudate rinsing decreased in the following order: citric acid > oxalic acid > malic acid. After elution, the total concentrations of phenanthrene and pyrene in sediment layers followed a descending order of bottom (9-12 cm) > middle (5-7 cm) > top (0-3 cm). Furthermore, a positive correlation between leachate pH values and PAH concentrations of the leachate was found. Consequently, the addition of root exudates can increase the leachability and bioavailability of phenanthrene and pyrene. PMID:26573317

  19. The variation of root exudates from the hyperaccumulator Sedum alfredii under cadmium stress: metabonomics analysis.

    Directory of Open Access Journals (Sweden)

    Qing Luo

    Full Text Available Hydroponic experiments were conducted to investigate the variation of root exudates from the hyperaccumulator Sedum alfredii under the stress of cadmium (Cd. S. alfredii was cultured for 4 days in the nutrient solution spiked with CdCl2 at concentrations of 0, 5, 10, 40, and 400 µM Cd after the pre-culture. The root exudates were collected and analyzed by GC-MS, and 62 compounds were identified. Of these compounds, the orthogonal partial least-squares discrimination analysis (OPLS-DA showed that there were a distinct difference among the root exudates with different Cd treatments and 20 compounds resulting in this difference were found out. Changing tendencies in the relative content of these 20 compounds under the different Cd treatments were analyzed. These results indicated that trehalose, erythritol, naphthalene, d-pinitol and n-octacosane might be closely related to the Cd stabilization, phosphoric acid, tetradecanoic acid, oxalic acid, threonic acid and glycine could be attributed to the Cd mobilization, and mannitol, oleic acid, 3-hydroxybutanoic acid, fructose, octacosanol and ribitol could copy well with the Cd stress.

  20. The variation of root exudates from the hyperaccumulator Sedum alfredii under cadmium stress: metabonomics analysis.

    Science.gov (United States)

    Luo, Qing; Sun, Lina; Hu, Xiaomin; Zhou, Ruiren

    2014-01-01

    Hydroponic experiments were conducted to investigate the variation of root exudates from the hyperaccumulator Sedum alfredii under the stress of cadmium (Cd). S. alfredii was cultured for 4 days in the nutrient solution spiked with CdCl2 at concentrations of 0, 5, 10, 40, and 400 µM Cd after the pre-culture. The root exudates were collected and analyzed by GC-MS, and 62 compounds were identified. Of these compounds, the orthogonal partial least-squares discrimination analysis (OPLS-DA) showed that there were a distinct difference among the root exudates with different Cd treatments and 20 compounds resulting in this difference were found out. Changing tendencies in the relative content of these 20 compounds under the different Cd treatments were analyzed. These results indicated that trehalose, erythritol, naphthalene, d-pinitol and n-octacosane might be closely related to the Cd stabilization, phosphoric acid, tetradecanoic acid, oxalic acid, threonic acid and glycine could be attributed to the Cd mobilization, and mannitol, oleic acid, 3-hydroxybutanoic acid, fructose, octacosanol and ribitol could copy well with the Cd stress. PMID:25545686

  1. Distribution of root exudates and mucilage in the rhizosphere: combining 14C imaging with neutron radiography

    Science.gov (United States)

    Holz, Maire; Carminati, Andrea; Kuzyakov, Yakov

    2015-04-01

    Water and nutrients will be the major factors limiting food production in future. Plant roots employ various mechanisms to increase the access to limited soil resources. Low molecular weight organic substances released by roots into the rhizosphere increase nutrient availability by interactions with microorganisms, while mucilage improves water availability under low moisture conditions. Though composition and quality of these substances have intensively been investigated, studies on the spatial distribution and quantification of exudates in soil are scarce. Our aim was to quantify and visualize root exudates and mucilage distribution around growing roots using neutron radiography and 14C imaging depending on drought stress. Plants were grown in rhizotrons well suited for neutron radiography and 14C imaging. Plants were exposed to various soil water contents experiencing different levels of drought stress. The water content in the rhizosphere was imaged during several drying/wetting cycles by neutron radiography. The radiographs taken a few hours after irrigation showed a wet region around the root tips showing the allocation and distribution of mucilage. The increased water content in the rhizosphere of the young root segments was related to mucilage concentrations by parameterization described in Kroener et al. (2014). In parallel 14C imaging of root after 14CO2 labeling of shoots (Pausch and Kuzyakov 2011) showed distribution of rhizodeposits including mucilage. Three days after setting the water content, plants were labeled in 14CO2 atmosphere. Two days later 14C distribution in soil was imaged by placing a phosphor-imaging plate on the rhizobox. To quantify rhizodeposition, 14C activity on the image was related to the absolute 14C activity in the soil and root after destructive sampling. By comparing the amounts of mucilage (neutron radiography) with the amount of total root derived C (14C imaging), we were able to differentiate between mucilage and root

  2. Root Exudates, Rhizosphere Zn Fractions, and Zn Accumulation of Ryegrass at Different Soil Zn Levels

    Institute of Scientific and Technical Information of China (English)

    XU Wei-Hong; LIU Huai; MA Qi-Fu; XIONG Zhi-Ting

    2007-01-01

    A glasshouse experiment was conducted using a root-bag technique to study the root exudates, rhizosphere Zn fractions, and Zn concentrations and accumulations of two ryegrass cultivars (Lolium perenne L. cvs. Airs and Tede) at different soil Zn levels (0, 2, 4, 8, and 16 mmol kg-1 soil). Results indicated that plant growth of the two cultivars was not adversely affected at soil Zn level≤8 mmol kg-1. Plants accumulated more Zn as soil Zn levels increased, and Zn concentrations of shoots were about 540 /μg g-1 in Aris and 583.9μg g-1 in Tede in response to 16 mmol Zn kg-1 soil. Zn ratios of shoots to roots across the soil Zn levels were higher in Tede than in Airs, corresponding with higher rhizosphere available Zn fractions (exchangeable, bound to manganese oxides, and bound to organic matter) in Airs than in Tede. Low-molecular-weight (LMW) organic acids (oxalic, tartaric, malic, and succinic acids) and amino acids (proline, threonine, glutamic acid, and aspartic acid, etc.) were detected in root exudates, and the concentrations of LMW organic acids and amino acids increased with addition of 4 mmol Zn kg-1 soil compared with zero Zn addition. Higher rhizosphere concentrations of oxalic acid, glutamic acid, alanine, phenylalanine, leucine, and proline in Tede than in Airs likely resulted in increased Zn uptake from the soil by Tede than by Airs. The results suggested that genotypic differences in Zn accumulations were mainly because of different root exudates and rhizosphere Zn fractions.

  3. Modeling Cesium Partitioning in the Rhizosphere: A Focus on the Role of Root Exudates

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Melinda Ann; Siegel, L. S.; Alshawabkeh, A. N.; Carl D. Palmer

    2003-01-01

    A conceptual model is being developed for prediction of cesium (Cs) partitioning between bound (Csb), aqueous (Csa), and phytoextracted (Csp) phases in the rhizosphere. The model categorizes the processes that impact cesium partitioning into six sub-models: geochemistry, physical factors, root density, microorganisms, nutrients, and root exudates. A seventh sub-model (Cs fate) describes Cs movement between the three phases. Functional relationships and parametric values within and between the submodels are being developed based on literature, field characterization, and laboratory experiments. Sensitivity analyses were conducted to evaluate the effects of root density, microbial population, potassium requirement and concentration, and moisture content on the concentration of root exudates ([E]) and consequently on Cs partitioning. In summary, the model provides a framework for better understanding the fundamental processes that control Cs fate in the rhizosphere. The ability to better understand, predict, and control Cs solubilization could be applied to other metals in the future. Ultimately, the model will be used as a tool for enhancing field implementation of in situ solubilization of metals for a variety of remedial activities.

  4. Enhanced hyphal growth of arbuscular mycorrhizae by root exudates derived from high R/FR treated Lotus japonicus.

    Science.gov (United States)

    Nagata, Maki; Yamamoto, Naoya; Miyamoto, Taro; Shimomura, Aya; Arima, Susumu; Hirsch, Ann M; Suzuki, Akihiro

    2016-06-01

    Red/Far Red (R/FR) sensing positively influences the arbuscular mycorrhizal (AM) symbiosis of both legume and nonlegume plants through jasmonic acid (JA) and strigolactone signaling. We previously reported that root exudates obtained from high R/FR-grown plants contained more strigolactone than low R/FR-grown plants. To determine whether JA and JA derivatives were secreted from roots, we investigated the expression levels of JA-responsive genes in L. japonicus Miyakojima MG20 plants treated with root exudates prepared from either high or low R/FR light-treated plants. The root exudates from high R/FR light-treated plants were found to enhance the expression levels of JA-responsive genes significantly. Moreover, exogenous JA increased AM fungal hyphal elongation as did the root exudates derived from high R/FR-grown L. japonicus plants. We conclude that increased JA accumulation and secretion into root exudates from high R/FR light-grown plants is the best explanation for increased colonization and enhanced mycorrhization under these conditions. PMID:27191935

  5. Influence of Aluminum and Cadmium Stresses on Mineral Nutrition and Root Exudates in Two Barley Cultivars

    Institute of Scientific and Technical Information of China (English)

    QUO Tian-Rong; ZHANG Guo-Ping; ZHOU Mei-Xue; WU Fei-Bo; CHEN Jin-Xin

    2007-01-01

    A hydroponic experiment was carried out to study the effect of aluminum (Al) and cadmium (Cd) on Al and mineral nutrient contents in plants and Al-induced organic acid exudation in two barley varieties with different Al tolerance. Al-sensitive cv. Shang 70-119 had significantly higher Al content and accumulation in plants than Al-tolerant cv. Gebeina, especially in roots, when subjected to low pH (4.0) and Al treatments (100 μmol L-1 Al and 100 μmol L-1 Al +1.0 μmol L-1 Cd). Cd addition increased Al content in plants exposed to Al stress. Both low pH and Al treatments caused marked reduction in Ca and Mg contents in all plant parts, P and K contents in the shoots and leaves, Fe, Zn and Mo contents in the leaves, Zn and B contents in the shoots, and Mn contents both in the roots and leaves. Moreover, changes in nutrient concentrations were greater in the plants exposed to both Al and Cd than in those exposed only to Al treatment. A dramatic enhancement of malate, citrate, and succinate was found in the plants exposed to 100 μmol L-1 Al relative to the control, and the Al-tolerant cultivar had a considerable higher exudation of these organic acids than the Al-sensitive one, indicating that Al-induced enhancement of these organic acids is very likely to be associated with Al tolerance.

  6. Growth stimulation of ectomycorrhizal fungi by root exudates of Brassicaceae plants: role of degraded compounds of indole glucosinolates.

    Science.gov (United States)

    Zeng, Ren Sen; Mallik, Azim U; Setliff, Ed

    2003-06-01

    Brassicaceae plants are nonmycorrhizal. They were found to inhibit VA mycorrhizal infection in their host plants. We tested if they can influence growth of ectomycorrhizal (ECM) fungi. When roots and leaves of Brassicaceae plants and ECM fungi were cultured together in the same petri dishes, the root exudates of turnip (Brassica rapa), swede (B. napobrassica), cabbage (B. oleracea, var. capitata), broccoli (B. oleracea, var. italica Plenck), kohlrobi (B. caulorapa Pasq.), mustard (B. juncea), radish (Raphanus sativus), and choy (B. napus) significantly stimulated hyphal growth of the ectomycorrhizal fungus Paxillus involutus. Root exudates of turnip and cabbage stimulated hyphal growth of Pisolithus tinctorius and two isolates of P. involutus. Colony area of P. involutus was increased by 452 and 414%, respectively, in the presence of turnip and cabbage germinants. Root exudates of turnip increased the biomass of P. involutus and P. tinctorius by 256 and 122% and cabbage by 220 and 82%, respectively. The stimulatory effect was not affected by autoclaving the root exudates. Root exudates had chemical reactions with glutathione and lysine, which resulted in a reduction of the growth stimulation of ECM fungi. Myrosinase enhanced further the stimulatory effects of turnip on the ECM colony diameter growth by 23%. Autoclaved roots and leaves of turnip did not stimulate fungal growth, but mechanically ground roots and leaves of turnip stimulated growth of P. involutus by 147 and 135%, respectively. After desulfuration with aryl sulphatuse, the glucosinolates (GLSs) in turnip roots and leaves were identified by HPLC. The major ones were indole GLSs. Prominent compounds identified were 1-methoxy-3-indolymethyl GLS and4-methoxy-3-indolymethyl GLS. The finding provides an opportunity to field test the use of Brassicaceae plants in enhancing ectomycorrhizal formation in conifers by interplanting conifers with Brassicaceae plants in forest tree nursery and agroforestry systems

  7. Isolation and identification of Desmodium root exudates from drought tolerant species used as intercrops against Striga hermonthica.

    Science.gov (United States)

    Hooper, A M; Caulfield, J C; Hao, B; Pickett, J A; Midega, C A O; Khan, Z R

    2015-09-01

    Plants from the genus Desmodium, in particular D. uncinatum, are used on sub-Saharan small-holder farms as intercrops to inhibit parasitism of cereal crops by Striga hermonthica and Striga asiatica via an allelopathic mechanism. The search for Desmodium species which are adapted to more arid conditions, and which show resilience to increased drought stress, previously identified D. intortum, D. incanum and D. ramosissimum as potential drought tolerant intercrops. Their potential as intercrops was assessed for resource poor areas of rain-fed cereal production where drought conditions can persist through normal meteorological activity, or where drought may have increasing impact through climate change. The chemical composition of the root exudates were characterised and the whole exudate biological activity was shown to be active in pot experiments for inhibition of Striga parasitism on maize. Furthermore, rain fed plot experiments showed the drought tolerant Desmodium intercrops to be effective for Striga inhibition. This work demonstrates the allelopathic nature of the new drought tolerant intercrops through activity of root exudates and the major compounds seen in the exudates are characterised as being C-glycosylflavonoid. In young plants, the exudates show large qualitative differences but as the plants mature, there is a high degree of convergence of the C-glycosylflavonoid exudate chemical profile amongst active Desmodium intercrops that confers biological activity. This defines the material for examining the mechanism for Striga inhibition. PMID:26164239

  8. Potential Enhancement of Plant Iron Assimilation by Microbial-Induced Root Exudation of Phenolic Compounds

    Directory of Open Access Journals (Sweden)

    Cheng Zhou

    2016-03-01

    Full Text Available Iron (Fe deficiency in crop plants is a modern agricultural problem worldwide. Although multiple strategies have been evolved to improve Fe assimilation, some plant species, especially dicots and nongraminaceous monocots (strategy I plants, cannot avoid Fe deficiency in low Fe-availability soils. It is well documented that graminaceous plants (strategy II plants employ the chelationbased Fe acquisition, and the strategy I plants use the reduction-based strategy to take up Fe. Intriguingly, under Fe deficiency the strategy I plants have recently been found to acquire Fe via exudation of phenolic compounds to mobilize Fe, which is much similar to the chelation-based mechanism of strategy II plants. Hitherto, increasing evidence has shown that soil microbes play a cooperative role in plant Fe acquisition. Several beneficial rhizobacteria have been found to increase plant Fe accumulation via activation of the reduction-based strategy. Moreover, microbial-induced root exudation of phenolic compounds can also promote plant Fe absorption by efficient mobilization of Fe, which increases Fe bioavailability in calcareous soils. Here, we briefly review the recent progress on the Fe assimilation strategies of strategy I and II plants, and further discuss the possible mechanisms underlying soil microbes enhance plant Fe acquisition.

  9. Lauric acid in crown daisy root exudate potently regulates root-knot nematode chemotaxis and disrupts Mi-flp-18 expression to block infection.

    Science.gov (United States)

    Dong, Linlin; Li, Xiaolin; Huang, Li; Gao, Ying; Zhong, Lina; Zheng, Yuanyuan; Zuo, Yuanmei

    2014-01-01

    Tomato (Solanum lycopersicum) crops can be severely damaged due to parasitism by the root-knot nematode (RKN) Meloidogyne incognita, but are protected when intercropped with crown daisy (Chrysanthemum coronarium L.). Root exudate may be the determining factor for this protection. An experiment using pots linked by a tube and Petri dish experiments were undertaken to confirm that tomato-crown daisy intercropping root exudate decreased the number of nematodes and alleviated nematode damage, and to determine crown daisy root exudate-regulated nematode chemotaxis. Following a gas chromatography-mass spectrometry assay, it was found that the intercropping protection was derived from the potent bioactivity of a specific root exudate component of crown daisy, namely lauric acid. The Mi-flp-18 gene, encoding an FMRFamide-like peptide neuromodulator, regulated nematode chemotaxis and infection by RNA interference. Moreover, it was shown that lauric acid acts as both a lethal trap and a repellent for M. incognita by specifically regulating Mi-flp-18 expression in a concentration-dependent manner. Low concentrations of lauric acid (0.5-2.0mM) attract M. incognita and consequently cause death, while high concentrations (4.0mM) repel M. incognita. This study elucidates how lauric acid in crown daisy root exudate regulates nematode chemotaxis and disrupts Mi-flp-18 expression to alleviate nematode damage, and presents a general methodology for studying signalling systems affected by plant root exudates in the rhizosphere. This could lead to the development of economical and feasible strategies for controlling plant-parasitic nematodes, and provide an alternative to the use of pesticides in farming systems. PMID:24170741

  10. Assessing bio-availability of metals in biosolid-amended soils: Root exudates and their effects on solubility of metals

    International Nuclear Information System (INIS)

    The existence of root exudates has been known to research scientists for a long time. Their role and function in plant nutrition and soil chemistry have only recently begun to be understood. The primary constituents of root exudates are low molecular weight organic acids that play an essential role in making the sparingly soluble soil Fe, P, and Zn available to plants. While root exudates are reasonably well characterized, the influence of environmental factors on their chemical composition and volume require further investigation. This study was initiated to investigate the role of root exudates on the solubilization and bioavailability of soil-borne heavy metals in biosolid-treated soils. Corn, wheat, canola, Sudan grass, chickpea, and Swiss chard were grown on standard and biosolid-treated sand media to characterize root exudates and evaluate the plants' metal-uptake patterns. Recent results indicate that: (i) the same organic acids were present over a 16-week growing season. However, the primary constituents of exudates from corn grown on standard sand media and biosolid-treated media were different. (ii) Metal concentrations in plant roots were considerably higher than those present in respective plant shoots, and plants grown in the biosolid-treated rooting medium had significantly higher concentrations of metals than those of the standard sand media at all stages of the growth. (iii) Based on mass present in the growth media and absorbed by corn, the phyto-availability of biosolid-borne metals were in the order: Cd > Ni = Zn > Cu = Pb > Cr. The availability of Mo was comparable to that of Cr. (iv) In the biosolidtreated growth medium, the uptake rates of Cd, Pb, and Zn by corn shoots (measured as mg of metal absorbed per g of biomass increment per unit time) were relatively constant over the active growing phase of the plants and were proportional to respective mass input of the metals. Work is in progress to define the role of root exudates on solubility

  11. Contrasting responses of root morphology and root-exuded organic acids to low phosphorus availability in three important food crops with divergent root traits

    OpenAIRE

    Wang, Yan-Liang; Almvik, Marit; Clarke, Nicholas; Eich-Greatorex, Susanne; Øgaard, Anne Falk; Krogstad, Tore; Lambers, Hans; Clarke, Jihong Liu

    2015-01-01

    Phosphorus (P) is an important element for crop productivity and is widely applied in fertilizers. Most P fertilizers applied to land are sorbed onto soil particles, so research on improving plant uptake of less easily available P is important. In the current study, we investigated the responses in root morphology and root-exuded organic acids (OAs) to low available P (1 μM P) and sufficient P (50 μM P) in barley, canola and micropropagated seedlings of potato—three important food crops with ...

  12. Flavonoids and Strigolactones in Root Exudates as Signals in Symbiotic and Pathogenic Plant-Fungus Interactions

    Directory of Open Access Journals (Sweden)

    Horst Vierheilig

    2007-07-01

    Full Text Available Secondary plant compounds are important signals in several symbiotic and pathogenic plant-microbe interactions. The present review is limited to two groups of secondary plant compounds, flavonoids and strigolactones, which have been reported in root exudates. Data on flavonoids as signaling compounds are available from several symbiotic and pathogenic plant-microbe interactions, whereas only recently initial data on the role of strigolactones as plant signals in the arbuscular mycorrhizal symbiosis have been reported. Data from other plant-microbe interactions and strigolactones are not available yet. In the present article we are focusing on flavonoids in plant-fungalinteractions such as the arbuscular mycorrhizal (AM association and the signaling between different Fusarium species and plants. Moreover the role of strigolactones in the AM association is discussed and new data on the effect of strigolactones on fungi, apart from arbuscular mycorrhizal fungi (AMF, are provided.

  13. Root exudates and leaf leachates of 19 medicinal plants of pakistan exhibit allelopathic potential

    International Nuclear Information System (INIS)

    Laboratory experiments were conducted to evaluate the allelopathic potential of root exudates and leaf leachates of 19 medicinal plants commonly used in Pakistan by plant box and sandwich methods, respectively. In sandwich method, lettuce seedlings were grown with the dry leaf leachates of the selected plant species in a growing media at the rate of 5, 10 and 50 mg dish-1 in a completely randomized design with three replications. Their effects on hypocotyl and radicle growth of the lettuce were recorded as a percentage of untreated control. Data was subjected for analysis of variance and treatment means were compared by Tukey's HSD test at p<0.05. Results indicated that allelopathic effects of the leaf leachates of all selected plant species on the hypocotyl and radicle elongations of the lettuce varied significantly in all concentrations used in experiments. The hypocotyl growth of the lettuce seedlings was affected from promotion (6.71% inhibition) caused by Phlaris minor to inhibition (78.40%) by Withania somnifera. Both species suppressed the radicle length from 33.69-93.30%. Leachates of W. somnifera and Sarcococca saligna exhibited strong inhibitory results in a concentration dependant manner. After the growth period of 50 days, root exudates of S. saligna appeared most detrimental (78.00% inhibition) to radicle growth of the lettuce seedling followed by W. somnifera (75.00%) when tested by plant box method. The results presented can be utilized as benchmark information for further joint research on the elucidation of chemicals involved in the allelopathy in nature and in the development of new and potent bioherbicides to combat environmental risk. (author)

  14. CONJUGAL GENE TRANSFER IN THE RHIZOSPHERE OF WATER GRASS (ECHINOCHLORA CRUSGALLI): INFLUENCE OF ROOT EXUDATE AND BACTERIAL ACTIVITY

    Science.gov (United States)

    The premise that genetic exchange is primarily localized in niches characterized by dense bacterial populations and high availability of growth substrates was tested by relating conjugal gene transfer of an RP4 derivative to availability of root exudates and bacterial metabolic a...

  15. Benzoxazinoids in root exudates of maize attract Pseudomonas putida to the rhizosphere.

    Directory of Open Access Journals (Sweden)

    Andrew L Neal

    Full Text Available Benzoxazinoids, such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H-one (DIMBOA, are secondary metabolites in grasses. In addition to their function in plant defence against pests and diseases above-ground, benzoxazinoids (BXs have also been implicated in defence below-ground, where they can exert allelochemical or antimicrobial activities. We have studied the impact of BXs on the interaction between maize and Pseudomonas putida KT2440, a competitive coloniser of the maize rhizosphere with plant-beneficial traits. Chromatographic analyses revealed that DIMBOA is the main BX compound in root exudates of maize. In vitro analysis of DIMBOA stability indicated that KT2440 tolerance of DIMBOA is based on metabolism-dependent breakdown of this BX compound. Transcriptome analysis of DIMBOA-exposed P. putida identified increased transcription of genes controlling benzoate catabolism and chemotaxis. Chemotaxis assays confirmed motility of P. putida towards DIMBOA. Moreover, colonisation essays in soil with Green Fluorescent Protein (GFP-expressing P. putida showed that DIMBOA-producing roots of wild-type maize attract significantly higher numbers of P. putida cells than roots of the DIMBOA-deficient bx1 mutant. Our results demonstrate a central role for DIMBOA as a below-ground semiochemical for recruitment of plant-beneficial rhizobacteria during the relatively young and vulnerable growth stages of maize.

  16. Effects of sorghum (sorghum bicolor L. root exudates on the cell cycle of the bean plant (phaseolus vulgaris L. root

    Directory of Open Access Journals (Sweden)

    Hallak Angela Maria Gattás

    1999-01-01

    Full Text Available Two experiments were conducted to test the allelopathic effect of sorghum (Sorghum bicolor L. root exudates on bean (Phaseolus vulgaris L. cell division. Research was conducted in the greenhouse of the Wistock Agricultural Research Institute of Minas Gerais State (EPAMIG and in a laboratory of the Federal University of Lavras (UFLA. Sorghum variety BR-601 and bean variety Carioca MG were used. The exudate, called sorgoleone (SGL, was obtained by methylene chloride and acetic acid extraction from sorghum roots seven days after sowing on Petri dishes, and refrigerated until use. Solutions of 0.01, 0.05, 0.10, and 0.15 mM were prepared using Johanson solution as the SGL solvent. Seven-day-old bean seedlings grown in vermiculite in a greenhouse were transplanted to the solution. Seven days after transplantation, the beans did not show any sign of phytotoxicity; however, cytogenetic observations showed that SGL reduced the number of cells in prophase, metaphase, and anaphase stages. Colchicine effects were observed among cells in metaphase on the third and fifth days after treatments and varied with SGL concentrations. By the seventh day, the colchicine effects were inversely proportional to concentration, which varied from 34.3% for 0.01 mM to 6.6% for 0.15 mM. SGL acts as a mitotic inhibitor. It probably depolymerizes the microtubular proteins and induces the formation of colchicine metaphases causing polyploid nuclei. A largest period of SGL treatment also induced chromosome breaks and bridge formation in anaphase and telophase. Although SGL cannot be used as a herbicide for bean cultures, its allelochemical effects on other cultures are the factors that will define the use of sorghum as a natural herbicide.

  17. Effects of Grafting on Root Exudates of Cucumber and Rhizosphere Environment under Copper Stress

    Institute of Scientific and Technical Information of China (English)

    Hua LI; Hongjun HE; Tengfei LI; Xin LI; Zikun ZHANG

    2013-01-01

    [Objective] This study to aimed to investigate the effects of Cu stress on root exudates and microbial activities in rhizosphere of grafted and ungrafted cucum-ber seedlings, and therefore to elucidate the microbial mechanism of grafting for in-creasing cucumber plants tolerance to Cu stress [Method] Four treatments: (1) un-grafted seedlings + test soil (U0); (2) ungrafted seedlings + test soil + CuSO4·5H2O (U1); (3) grafted seedlings + test soil (G0); (4) grafted seedlings + test soil + Cu-SO4·5H2O (G1) were set in the pot culture experiment. The contents of free amino acids, organic acids, phenolic acid and sugars, microbial population and enzyme ac-tivity in the four treatment were measured, respectively. [Result] The secretion of amino acids and organic acids were increased under Cu stress. The amino acids secretions of grafted seedlings roots were obviously higher than ungrafted seedlings except for Phe and Val. At the same time, the secretion of oxalic acid, malic acid, acetic acid, citric acid, cinnamic acid, ρ-hydroxybenzoic acid and benzoic acid of grafted seedlings were significantly higher than ungrafted seedlings as wel . There-fore, more Cu2+ were restricted in soil by chelating, complexing and precipitation with root exudates, and its toxicity was decreased. The soil microbial biomass C and N in grafted cucumber rhizosphere were significantly higher than those in ungrafted cu-cumber rhizosphere, whereas basal respiration and metabolic quotient were signifi-cantly lower. Under Cu stress, the numbers of actinomyces and nitrogen fixing bac-teria decreased and the number of fungi increased significantly, whereas there was no significant difference in amounts of bacteria. The numbers of bacteria, actino-myces, and nitrogen fixing bacteria in grafted cucumber rhizosphere were significant-ly higher than those in ungrafted cucumber rhizosphere, but the number of fungi was opposite. The activities of soil urease, phosphatase, sucrase and catalase in grafted

  18. Aluminum resistance in common bean (Phaseolus vulgaris) involves induction and maintenance of citrate exudation from root apices.

    Science.gov (United States)

    Rangel, Andrés Felipe; Rao, Idupulapati Madhusudana; Braun, Hans-Peter; Horst, Walter Johannes

    2010-02-01

    Two common bean (Phaseolus vulgaris L.) genotypes differing in aluminum (Al) resistance, Quimbaya (Al-resistant) and VAX-1 (Al-sensitive) were grown in hydroponics for up to 25 h with or without Al, and several parameters related to the exudation of organic acids anions from the root apex were investigated. Al treatment enhanced the exudation of citrate from the root tips of both genotypes. However, its dynamic offers the most consistent relationship between Al-induced inhibition of root elongation and Al accumulation in and exclusion from the root apices. Initially, in both genotypes the short-term (4 h) Al-injury period was characterized by the absence of citrate efflux independent of the citrate content of the root apices, and reduction of cytosolic turnover of citrate conferred by a reduced Nicotinamide adenine dinucleotide phosphate-isocitrate dehydrogenase (EC 1.1.1.42) activity. Transient recovery from initial Al stress (4-12 h) was found to be dependent mainly on the capacity to utilize internal citrate pools (Al-resistant genotype Quimbaya) or enhanced citrate synthesis [increased activities of NAD-malate dehydrogenase (EC 1.1.1.37) and ATP-phosphofructokinase (EC 2.7.1.11) in Al-sensitive VAX-1]. Sustained recovery from Al stress through citrate exudation in genotype Quimbaya after 24 h Al treatment relied on restoring the internal citrate pool and the constitutive high activity of citrate synthase (CS) (EC 4.1.3.7) fuelled by high phosphoenolpyruvate carboxylase (EC 4.1.1.31) activity. In the Al-sensitive genotype VAX-1 the citrate exudation and thus Al exclusion and root elongation could not be maintained coinciding with an exhaustion of the internal citrate pool and decreased CS activity. PMID:20053183

  19. Increased root exudation of 14C-compounds by sorghum seedlings inoculated with nitrogen-fixing bacteria

    International Nuclear Information System (INIS)

    Organic components leaked from Sorghum bicolor seedlings ('root exudates') were examined by recovering 14C labelled compounds from root solutions of seedlings inoculated with Azospirillum brasilense, Azotobacter vinelandii or Klebsiella pneumoniae nif-. Up to 3.5% of the total 14C recovered from shoots, roots, and nutrient solutions was found in the root solutions. Inoculation with Azospirillum and Azotobacter increased the amounts of 14C and decreased the amounts of carbohydrates in the root solutions. When sucrose was added as a carbon source for the bacteria, the increase of 14C in the solutions did not occur. Quantities of 14C found in the root solutions were proportional to amounts of mineral nitrogen supplied to the plants. Bacterial growth also was proportional to nitrogen levels. When sorghum plants were grown in soil and labelled with 14CO2, about 15% of the total 14C recovered within 48 hours exposure was found in soil leachates. (orig.)

  20. Benzo[a]pyrene co-metabolism in the presence of plant root extracts and exudates: Implications for phytoremediation

    International Nuclear Information System (INIS)

    Benzo[a]pyrene, a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) was removed from solution by Sphingomonas yanoikuyae JAR02 while growing on root products as a primary carbon and energy source. Plant root extracts of osage orange (Maclura pomifera), hybrid willow (Salix albaxmatsudana), or kou (Cordia subcordata), or plant root exudates of white mulberry (Morus alba) supported 15-20% benzo[a]pyrene removal over 24 h that was similar to a succinate grown culture and an unfed acetonitrile control. No differences were observed between the different root products tested. Mineralization of 14C-7-benzo[a]pyrene by S. yanoikuyae JAR02 yielded 0.2 to 0.3% 14CO2 when grown with plant root products. Collectively, these observations were consistent with field observations of enhanced phytoremediation of HMW PAH and corroborated the hypothesis that co-metabolism may be a plant/microbe interaction important to rhizoremediation. However, degradation and mineralization was much less for root product-exposed cultures than salicylate-induced cultures, and suggested the rhizosphere may not be an optimal environment for HMW PAH degradation by Sphingomonas yanoikuyae JAR02. - Bacterial benzo[a]pyrene cometabolism, a plant-microbe interaction affecting polycyclic aromatic hydrocarbon phytoremediation was demonstrated with Sphingomonas yanoikuyae JAR02 that utilized plant root extracts and exudates as primary substrates

  1. Two mire species respond differently to enhanced ultraviolet-B radiation: effects on biomass allocation and root exudation

    DEFF Research Database (Denmark)

    Rinnan, Riikka Tiivi Mariisa; Gehrke, Carola; Michelsen, Anders

    2006-01-01

    •  Increased ultraviolet-B (UV-B) radiation arising from stratospheric ozone depletion may influence soil microbial communities via effects on plant carbon allocation and root exudation. •  Eriophorum angustifolium and Narthecium ossifragum plants, grown in peatland mesocosms consisting of Sphagnum...... peat, peat pore water and natural microbial communities, were exposed outdoors to enhanced UV-B radiation simulating 15% ozone depletion in southern Scandinavia for 8 wk. •  Enhanced UV-B increased rhizome biomass and tended to decrease the biomass of the largest root fraction of N...

  2. Rhizosphere priming effect on soil organic carbon decomposition under plant species differing in soil acidification and root exudation.

    Science.gov (United States)

    Wang, Xiaojuan; Tang, Caixian; Severi, Julia; Butterly, Clayton R; Baldock, Jeff A

    2016-08-01

    Effects of rhizosphere properties on the rhizosphere priming effect (RPE) are unknown. This study aimed to link species variation in RPE with plant traits and rhizosphere properties. Four C3 species (chickpea, Cicer arietinum; field pea, Pisum sativum; wheat, Triticum aestivum; and white lupin, Lupinus albus) differing in soil acidification and root exudation, were grown in a C4 soil. The CO2 released from soil was trapped using a newly developed NaOH-trapping system. White lupin and wheat showed greater positive RPEs, in contrast to the negative RPE produced by chickpea. The greatest RPE of white lupin was in line with its capacity to release root exudates, whereas the negative RPE of chickpea was attributed to its great ability to acidify rhizosphere soil. The enhanced RPE of field pea at maturity might result from high nitrogen deposition and release of structural root carbon components following root senescence. Root biomass and length played a minor role in the species variation in RPE. Rhizosphere acidification was shown to be an important factor affecting the magnitude and direction of RPE. Future studies on RPE modelling and mechanistic understanding of the processes that regulate RPE should consider the effect of rhizosphere pH. PMID:27101777

  3. Plant root-driven hydraulic redistribution, root nutrient uptake and carbon exudation interact with soil properties to generate rhizosphere resource hotspots that vary in space and time

    Science.gov (United States)

    Espeleta, J. F.; Neumann, R. B.; Cardon, Z. G.; Mayer, K. U.; Rastetter, E. B.

    2014-12-01

    Hydraulic redistribution (HR) of soil water by plants occurs in seasonally dry ecosystems worldwide. During drought, water flows from deep moist soil, through plant roots, into dry (often litter-rich) upper soil layers. Using modeling, we explored how physical transport processes driven by transpiration and hydraulic redistribution interact with root physiology (nutrient uptake and carbon exudation) and soil properties (soil texture and cation exchange) to influence nitrogen and carbon concentrations in the rhizosphere. At the single root scale, we modeled a 10-cm radial soil domain, and simulated solute transport, soil cation exchange, and root exudation and nutrient uptake under two water flow patterns: daytime transpiration without nighttime HR, and daytime transpiration with nighttime HR. During HR, water efflux flushed solutes away from the root, diluting the concentrations of key nutrients like nitrate. The transport of cations by transpiration in the day and their accumulation near the root led to competitive desorption of ammonium from soil further from the root and generation of hotspots of ammonium availability at night. HR influenced the spatial and temporal patterns of these hotspots and their intensity. They were also influenced by soil properties of texture and cation exchange capacity. This dynamic resource landscape caused by diel cycling between transpiration and hydraulic redistribution presents a stage for greater complexity of microbial interactions. We are currently embedding a microbial community and small food web into this rhizosphere model in order to explore how organisms responsible for nutrient and soil carbon cycling respond to these fluctuating resource regimes.

  4. EFFECT OF ROOT EXUDATES OF SENGON PLANT (Paraserianthes falcataria L. Nielsen) INOCULATED WITH FUNGAL ENDOPHYTE, Nigrospora sp. ON CONTROL OF ROOT-KNOT NEMATODE Meloidogyne spp.???

    OpenAIRE

    Nur, Amin

    2012-01-01

    Endophytic fungi are fungi that live within their host plant tissues without causing any symptoms on the host. A host plant and endophytic fungi living on it have a mutulistic relathionship. The host provides substrate and space for the endophytes to grow while the fungal endophytes promote plant growth and protect the plant hosts from pests and diseases. The research was aimed to determine the effect of different concentrations of root exudates of sengon plant (Paraserianthes falcataria) ...

  5. The Content of Phenolic Compounds in the Pea Seedling Root Exudates Depends on the Size of Their Roots and Inoculation of Bacteria Mutualistic and Antagonistic Type of Interactions

    OpenAIRE

    L.E. Makarova; L.V. Dudareva; I.G. Petrova

    2015-01-01

    The effect of the bacteria Rhizobium and Pseudomonas on total content of phenolic compounds (PC) and their individual components (apigenin, naringenin, dibutyl-ortho-phthalate, pisatin, N-phenyl-2-naphthylamine) in the root exudates of the pea seedlings (Pisum sativum L. ) at two different growth stages was studied . Bacteria have similar affect on the total number of PC and the number of constituent apigenine, phthalate and pisatine. Difference at the impact of these bacteria on the content ...

  6. Non-targeted profiling of semi-polar metabolites in Arabidopsis root exudates uncovers a role for coumarin secretion and lignification during the local response to phosphate limitation.

    Science.gov (United States)

    Ziegler, Jörg; Schmidt, Stephan; Chutia, Ranju; Müller, Jens; Böttcher, Christoph; Strehmel, Nadine; Scheel, Dierk; Abel, Steffen

    2016-03-01

    Plants have evolved two major strategies to cope with phosphate (Pi) limitation. The systemic response, mainly comprising increased Pi uptake and metabolic adjustments for more efficient Pi use, and the local response, enabling plants to explore Pi-rich soil patches by reorganization of the root system architecture. Unlike previous reports, this study focused on root exudation controlled by the local response to Pi deficiency. To approach this, a hydroponic system separating the local and systemic responses was developed. Arabidopsis thaliana genotypes exhibiting distinct sensitivities to Pi deficiency could be clearly distinguished by their root exudate composition as determined by non-targeted reversed-phase ultraperformance liquid chromatography electrospray ionization quadrupole-time-of-flight mass spectrometry metabolite profiling. Compared with wild-type plants or insensitive low phosphate root 1 and 2 (lpr1 lpr2) double mutant plants, the hypersensitive phosphate deficiency response 2 (pdr2) mutant exhibited a reduced number of differential features in root exudates after Pi starvation, suggesting the involvement of PDR2-encoded P5-type ATPase in root exudation. Identification and analysis of coumarins revealed common and antagonistic regulatory pathways between Pi and Fe deficiency-induced coumarin secretion. The accumulation of oligolignols in root exudates after Pi deficiency was inversely correlated with Pi starvation-induced lignification at the root tips. The strongest oligolignol accumulation in root exudates was observed for the insensitive lpr1 lpr2 double mutant, which was accompanied by the absence of Pi deficiency-induced lignin deposition, suggesting a role of LPR ferroxidases in lignin polymerization during Pi starvation. PMID:26685189

  7. Effect of Soil Moisture on Release of Low-MolecularWeight Organic Acids in Root Exudates and the Accumulation of Iron in Root Apoplasm of Peanut

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A three-compartments rhizobox was designed and used to study the low-molecular-weight organic acids in root exudates and the root apoplastic iron of "lime-induced chlorosis" peanut grown on a calcareous soil in relation to different soil moisture conditions. Results showed that chlorosis of peanuts developed under condition of high soil moisture level (250 g kg-1), while peanuts grew well and chlorosis did not develop when soil moisture was managed to a normal level (150 g kg-1). The malic acid, maleic acid and succinic acid contents of chlorotic peanut increased by 108.723, 0.029 and 22.446μg cm-2, respectively,compared with healthy peanuts. The content of citric acid and fumaric acid also increased in root exudates of chlorotic peanuts. On Days 28 and 42 of peanut growth, the accumulation of root apoplastic iron in chlorotic peanuts was higher than that of healthy peanuts. From Day 28 to Day 42, the mobilization percentages of chlorotic peanuts and healthy peanuts to root apoplastic iron were almost the same, being 52.4% and 52.8%,respectively, indicating that the chlorosis might be caused by the inactivation of iron within peanut plant grown on a calcareous soil under high soil moisture conditions.

  8. VARIATION IN RHIZOBIUM GROWTH DUE TO SEED AND ROOT EXUDATES RELEASED FROM GAMMA IRRADIATED GLYCINE MAX SEEDS

    International Nuclear Information System (INIS)

    In this study, seeds of Glycine max Giza 122 were irradiated with gamma rays from 60Co source at various doses (10 to 200 Gy), sterilized and soaked into an aerated solution of CaSO4 (1 mmol and pH 6.5). The capacities of the released seed exudates (SEs) and root exudates (REs) to promote Rhizobium leguminosarum growth were investigated as well as biochemical analysis of the exudates was carried out. SE of both control and gamma irradiated seeds resulted in a higher Rhizobium population and polysaccharide production than RE. Relative to control, the highly effective doses in Rhizobium growth and polysaccharide production were 25 and 200 Gy; the former was a promoter while the later was an inhibitor. HPLC analysis of soluble carbohydrates revealed the presence of glucose (Glu), rhamnose (Rha) and fructose (Fru) in the SE and RE. Protein content in SE was lower than that in RE; the highest values were due to 10 Gy and 25 Gy in SE and RE, respectively. Free amino acids content in SE was increased up to 25 Gy then decreased while RE was increased by increasing gamma doses from 10 to 200 Gy

  9. Effects of root exudates of bivalent transgenic cotton (Bt+CpTI) plants on antioxidant proteins and growth of conventional cotton (Xinluhan 33).

    Science.gov (United States)

    Wu, Hong-Sheng; Shi, Xue; Li, Ji; Wu, Tian-Yu; Ren, Qian-Qi; Zhang, Zhen-Hua; Wang, Ming-Yan; Shang, Xiao-Xia; Liu, Yan; Xiao, Song-Hua

    2016-01-01

    A greenhouse experiment was conducted to assess the adverse impact of transgenic cotton on ecosystem and environment via effect of transgenic Bt+CpTI cotton root exudates on growth and antioxidant activity of conventional parental cotton. Results showed elevated reductive and oxidative species activities in the leaves of conventional parental cotton seedlings treated with varying concentrations of transgenic cotton root exudates. Compared to control, 14.9% to 39.9% increase in catalase, 8.8% to 114% increase in for peroxidase, 21.3% to 59.7% increase in phenylalanine ammonia-lyase and 5.8 to 19.5 fold in ascorbate specific peroxidase was observed. However, biomass and height of conventional cotton seedlings were not affected by any concentration of transgenic cotton root exudates. These results suggested that cultivation of transgenic Bt+CpTI cotton plants poses little risk to conventional parental cotton based on their root interactions. PMID:26930855

  10. Root-exuded acid phosphatase and 32Pi-uptake kinetics of wheat, rye and triticale under phosphorus starvation

    International Nuclear Information System (INIS)

    A nutrient culture experiment was conducted with cereal species viz., wheat (Triticum aestivum L.) cv. PBW-343), rye (Secale cereale L cv. R-308) and triticale (Triticale octoploide L. cv. DT-46), a hybrid of wheat and rye, to examine the genetic variation in root-exuded acid phosphatase (ACPase) activity and kinetics of 32Pi-uptake under P deficient condition. The ACPase activity was assayed in the extract (intra-) and on surface (extra-cellular) or root, using p-nitrophenyl phosphate as substrate. Significantly higher ACPase activity was observed in wheat followed by rye and triticale both on the root surface and in root extract. In general, root surface ACPase activity was 2.2-fold higher than that in root extract. A strong correlation (r2 = 0.87**) between extra and intra-cellular ACPase activity was observed. In terms of kinetic parameters, it was observed that 32Pi uptake and Imax values were significantly higher in rye while Cmin and Km were lowest compared to wheat and triticale. The dry weights of shoot, root and total plant were significantly higher in rye compared to wheat and triticale. Rye also had higher amount of total plant P content The superiority of rye over wheat and triticale in P uptake was observed mainly due to efficient Pi-uptake system, which needs further studies to ascertain the enhancement of Pi-induced high-affinity P transporter in these cereals. (author)

  11. Increased root exudation of /sup 14/C-compounds by sorghum seedlings inoculated with nitrogen-fixing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.J. (Institute of Forest Genetics, Suweon (Republic of Korea)); Gaskins, M.H. (Florida Univ., Gainesville (USA). Dept. of Agriculture)

    1982-01-01

    Organic components leaked from Sorghum bicolor seedlings ('root exudates') were examined by recovering /sup 14/C labelled compounds from root solutions of seedlings inoculated with Azospirillum brasilense, Azotobacter vinelandii or Klebsiella pneumoniae nif-. Up to 3.5% of the total /sup 14/C recovered from shoots, roots, and nutrient solutions was found in the root solutions. Inoculation with Azospirillum and Azotobacter increased the amounts of /sup 14/C and decreased the amounts of carbohydrates in the root solutions. When sucrose was added as a carbon source for the bacteria, the increase of /sup 14/C in the solutions did not occur. Quantities of /sup 14/C found in the root solutions were proportional to amounts of mineral nitrogen supplied to the plants. Bacterial growth also was proportional to nitrogen levels. When sorghum plants were grown in soil and labelled with /sup 14/CO/sub 2/, about 15% of the total /sup 14/C recovered within 48 hours exposure was found in soil leachates.

  12. The role of organic acids exuded from roots in phosphorus nutrition and aluminium tolerance in acidic soils

    International Nuclear Information System (INIS)

    Soil acidity is a major problem of large areas of arable land on a global scale. Many acid soils are low in plant-available phosphorus (P) or are highly P-fixing, resulting in poor plant growth. In addition, aluminium (Al) is soluble in acid soils in the toxic Al3+ form, which also reduces plant growth. There is considerable evidence that both P deficiency and exposure to Al3+ stimulate the efflux of organic acids from roots of a range of species. Organic acids such as citrate, malate and oxalate are able to desorb or solubilise fixed soil P, making it available for plant uptake. Organic acids also chelate Al3+ to render it non-toxic, and are, therefore, involved in Al tolerance mechanisms. In this review, we discuss the literature on the role of organic acids exuded from roots in improving plant P uptake and Al-tolerance in acid soils. Research is now attempting to understand how P deficiency or exposure to Al3+ activates or induces organic acid efflux at the molecular level, with the aim of improving P acquisition and Al tolerance by conventional plant breeding and by genetic engineering. At the agronomic level, it is desirable that existing crop and pasture plants with enhanced soil-P uptake and tolerance to Al due to organic acid exudation are integrated into farming systems. (author)

  13. Isoschaftoside, a C-glycosylflavonoid from Desmodium uncinatum root exudate, is an allelochemical against the development of Striga.

    Science.gov (United States)

    Hooper, Antony M; Tsanuo, Muniru K; Chamberlain, Keith; Tittcomb, Kay; Scholes, Julie; Hassanali, Ahmed; Khan, Zeyaur R; Pickett, John A

    2010-06-01

    In East African small-holder farming of maize, the cattle forage legume, Desmodium uncinatum is used as an intercrop due to its allelopathic inhibition of parasitism by Striga hermonthica, an obligate parasitic weed that can devastate the maize crop. Bioassay-guided fractionation of the root extract of D. uncinatum revealed isoschaftoside to be the main compound in the most potent fraction inhibiting growth of germinated S. hermonthica radicles. Bioassays repeated with isoschaftoside isolated from a different plant source, Passiflora incarnata, proved it to be a biologically active component. Analysis of the root exudates produced by hydroponically grown D. uncinatum showed isoschaftoside to be present in the hydroponic media at biologically active concentrations of 10-100 nM. PMID:20211477

  14. The Content of Phenolic Compounds in the Pea Seedling Root Exudates Depends on the Size of Their Roots and Inoculation of Bacteria Mutualistic and Antagonistic Type of Interactions

    Directory of Open Access Journals (Sweden)

    L.E. Makarova

    2015-09-01

    Full Text Available The effect of the bacteria Rhizobium and Pseudomonas on total content of phenolic compounds (PC and their individual components (apigenin, naringenin, dibutyl-ortho-phthalate, pisatin, N-phenyl-2-naphthylamine in the root exudates of the pea seedlings (Pisum sativum L. at two different growth stages was studied . Bacteria have similar affect on the total number of PC and the number of constituent apigenine, phthalate and pisatine. Difference at the impact of these bacteria on the content of naringenin and N-phenyl-2-naphthylamine was detected, which can be attributed to the peculiarities of the interactions of plants of peas with bacteria-antagonists and mutualists.

  15. Aluminum tolerance of two wheat cultivars (Brevor and Atlas66) in relation to their rhizosphere pH and organic acids exuded from roots.

    Science.gov (United States)

    Wang, Ping; Bi, Shuping; Ma, Liping; Han, Weiying

    2006-12-27

    Phytotoxicity of aluminum (Al) has become a serious problem in inhibiting plant growth on acid soils. Under Al stress, the changes of rhizosphere pH, root elongation, absorption of Al by wheat roots, organic acids exuded from roots, and some main factors related to Al-tolerant mechanisms have been studied using hydroponics, fluorescence spectrophotometry, and high performance liquid chromatography (HPLC). Two wheat cultivars, Brevor and Atlas66, differing in Al tolerance are chosen in the study. Accordingly, the rhizosphere pH has a positive effect on Al tolerance. Atlas66 (Al-tolerant) has higher capability to maintain high rhizosphere pH than Brevor (Al-sensitive) does. High pH can reduce Al3+ activity and toxicity, and increase the efficiency of exuding organic acids from the roots. More inhibition of root elongation has been found in Brevor because of the exposure of roots to Al3+ solution at low pH. Brevor accumulate more Al in roots than Atlas66 even at higher pH. Al-induced exudation of malic and citric acids has been found in Atlas66 roots, while no Al-induced organic acids have been found in Brevor. These results indicate that the Al-induced secretion of organic acids from Atlas66 roots has a positive correlation with Al tolerance. Comprehensive treatment of Al3+ and H+ indicates that wheat is adversely influenced by excess Al3+, rather than low pH. PMID:17177538

  16. Trichoderma spp. Improve growth of Arabidopsis seedlings under salt stress through enhanced root development, osmolite production, and Na⁺ elimination through root exudates.

    Science.gov (United States)

    Contreras-Cornejo, Hexon Angel; Macías-Rodríguez, Lourdes; Alfaro-Cuevas, Ruth; López-Bucio, José

    2014-06-01

    Salt stress is an important constraint to world agriculture. Here, we report on the potential of Trichoderma virens and T. atroviride to induce tolerance to salt in Arabidopsis seedlings. We first characterized the effect of several salt concentrations on shoot biomass production and root architecture of Arabidopsis seedlings. We found that salt repressed plant growth and root development in a dose-dependent manner by blocking auxin signaling. Analysis of the wild type and eir1, aux1-7, arf7arf19, and tir1abf2abf19 auxin-related mutants revealed a key role for indole-3-acetic acid (IAA) signaling in mediating salt tolerance. We also found that T. virens (Tv29.8) and T. atroviride (IMI 206040) promoted plant growth in both normal and saline conditions, which was related to the induction of lateral roots and root hairs through auxin signaling. Arabidopsis seedlings grown under saline conditions inoculated with Trichoderma spp. showed increased levels of abscissic acid, L-proline, and ascorbic acid, and enhanced elimination of Na⁺ through root exudates. Our data show the critical role of auxin signaling and root architecture to salt tolerance in Arabidopsis and suggest that these fungi may enhance the plant IAA level as well as the antioxidant and osmoprotective status of plants under salt stress. PMID:24502519

  17. Determination of Organi Acids in Root Exudates by High Performance Liquid Chromatorgraphy:Ⅰ.Develop—ment and Assessment of Chromatographic Conditions

    Institute of Scientific and Technical Information of China (English)

    SHENJIANBO; ZHANGFUSUO; 等

    1998-01-01

    Methods for determining niene low molecular-weight oragnic acids in root exudates were developed by using reversed-phase high performance liquied chromatography with UV (ultraviolet) detection at 214 nm. The mobile phase was 18 mmol L-1 kH2PO4 adjusted to pH 2.25 with phosporic acid nd the flow rate was 0.3 mL min-1,The analytical column was a reversed-phase silica based C-18 column( shim-pack CLC-ODS).The root exudates were collected through submerging the whole root system into aerated deionized water for 2 hours ,The filtered exudate solutions were concentrated to dryness by rotary evaporation at 40℃,dissolved in 10 mL mobile phase.The chromatoraphic conditions of organic acid determination were analyzed.The results showed that there was a high selectivity and sensitivity in the organic acid determination by reversed-phase high performance liquid chromatography.Coefficients of variation for organic acied determination were lower than 10% except lactic acid .The recoveries were consistently between 80.1% to 108.3% .Detection limits were approximately 0.05 to 4.5 mg L-1 for organic acids except succinic acid with the detection limit of 7.0 mg L-1 .Phosphorus deficiency may contribute to the release of organic acids in soybean root exudates especially malic,lactic and citric acids.

  18. INFLUENCE OF ROOT EXUDATES AND BACTERIAL METABOLIC ACTIVITY ON APPARENT CONJUGAL GENE TRANSFER FREQUENCIES IN THE RHIZOSPHERE OF WATER GRASS (ECHINOCLORA CRUSGALLI)

    Science.gov (United States)

    The premise that genetic exchange is primarily localized in niches characterized by dense bacterial populations and high availability of growth substrates was tested by relating conjugal gene transfer of an RP4 derivative to availability of root exudates and bacterial metabolic a...

  19. 14CO2 labeling. A reliable technique for rapid measurement of total root exudation capacity and vascular sap flow in crop plants

    International Nuclear Information System (INIS)

    Root release of organic compounds and rate of the vascular sap flow are important for understanding the nutrient and the source-sink dynamics in plants, however, their determination is procedurally cumbersome and time consuming. We report here a simple method involving 14C labeling for rapid and reliable measurement of root exudates and vascular sap flow rate in a variable groundnut population developed through seed gamma irradiation using a cobalt source (60Co). An experimental hypothesis that a higher 14C level in the vascular sap would indicate a higher root release of carbon by the roots into the rhizosphere was verified. (author)

  20. Auxin effects on Pb phytoextraction from polluted soils by Tegetes minuta L. and Bidens pilosa L.: Extractive power of their root exudates.

    Science.gov (United States)

    Salazar, María Julieta; Rodriguez, Judith Hebelen; Cid, Carolina Vergara; Pignata, María Luisa

    2016-07-01

    The principal impediment for Pb uptake by plants is the Casparian strip in roots. It prevents metals reaching the xylem, thereby hampering translocation to the aerial organs. In the root apices, young root cells have thin cell walls and the Casparian strip is not completely developed, which could facilitate Pb uptake by roots at these vulnerable points. However, as the phytotoxic effects of Pb reduce root growth and enhance suberization, entry of Pb into the plant is avoided. We propose that the application of root growth promotors could be an important complement in the phytoextraction of Pb from polluted soils, due to their effects on produced biomass, Pb toxicity, and root exudate production. A greenhouse experiment was carried on to evaluate the auxin application effect on the Pb uptake of Bidens pilosa and Tagetes minuta. These species were sensitive to auxins, but the phytotoxic effect of Pb was not reversed by this treatment. Root exudates capable of extracting Pb were produced only when the species were grown in highly polluted soils, indicating a behavioral response to Pb exposure which is desirable for phytoremediation. PMID:26954477

  1. [Secretion of Phenolic Compounds into Root Exudates of Pea Seedlings upon Inoculation with Rhizobium leguminosarum bv. viceae or Pseudomonas siringae pv. Pisi].

    Science.gov (United States)

    Makarova, L E; Dudareva, L V; Petrova, I G; Vasil'eva, G G

    2016-01-01

    The content of apigenin, naringenin, pisatin, dibutyl-ortho-phthalate, and N-phenyl-2-naphthyl-amine were assayed in root exudates of pea (Pisum sativum L.) seedlings one day after their inoculation with Rhizobium leguminosarum, bv. viceae or Pseudomonas siringae pv. pisi, which represent, respectively, mutualistic and antagonistic strategies of interaction with a host plant. After inoculation with either bacteria, the concentrations of apigenin and pisatin in the root exudates were equal, whereas the concentrations of naringenin and N-phenyl-2-naphthylamine were different and those of dibutyl-o-phthalate were unchanged. A certain role is suggested for the phenolic compounds in an accomplishment of symbiotic relations of bacteria with a host plant. PMID:27266251

  2. 烟草根系分泌物的GC-MS检测%Determination of tobacco root exudates by GC-MS

    Institute of Scientific and Technical Information of China (English)

    于会泳; 申国明; 高欣欣

    2013-01-01

    采用水培试验研究对连作障碍有重大影响的烟草根系分泌物中的化感物质,利用GC-MS检测出了K326和NC89两个烤烟品种移栽后40天根系分泌物中的酸溶性、碱溶性和中溶性组分种类,结果表明,两个烤烟品种共有的根系分泌物中可能是化感物质的种类包括有机酸类、酰胺类、酯类以及甘油和烟碱。%Hydroponic experiments were conducted to study allelochemicals released by tobacco root exudation. Acidic, neutral and alkaline soluble root exudates were extracted, separated and identified 40 days after K326 and NC89 plants were transplanted. Results showed that allelochemicals from root exudates of both cultivars were organic acids, lactam, esters, glycerol and nicotine.

  3. Bioavailable concentrations of germanium and rare earth elements in soil as affected by low molecular weight organic acids and root exudates

    Science.gov (United States)

    Wiche, Oliver; Székely, Balázs; Kummer, Nicolai-Alexeji; Heinemann, Ute; Tesch, Silke; Heilmeier, Hermann

    2014-05-01

    Availability of elements in soil to plant is generally dependent on the solubility and mobility of elements in soil solution which is controlled by soil, elemental properties and plant-soil interactions. Low molecular organic acids or other root exudates may increase mobility and availability of certain elements for plants as an effect of lowering pH in the rhizosphere and complexation. However, these processes take place in a larger volume in soil, therefore to understand their nature, it is also important to know in which layers of the soil what factors modify these processes. In this work the influence of citric acid and root exudates of white lupin (Lupinus albus L.) on bioavailable concentrations of germanium, lanthan, neodymium, gadolinium and erbium in soil solution and uptake in root and shoot of rape (Brassica napus L.), comfrey (Symphytum officinale L.), common millet (Panicum milliaceum L.) and oat (Avena sativa L.) was investigated. Two different pot experiments were conducted: (1) the mentioned plant species were treated with nutrient solutions containing various amount of citric acid; (2) white lupin was cultivated in mixed culture (0 % lupin, 33 % lupin) with oat (Avena sativa L.) and soil solution was obtained by plastic suction cups placed at various depths. As a result, addition of citric acid significantly increased germanium concentrations in plant tissue of comfrey and rape and increased translocation of germanium, lanthan, neodymium, gadolinium and erbium from root to shoot. The cultivation of white lupin in mixed culture with oat led to significantly higher concentrations of germanium and increasing concentrations of lanthan, neodymium, gadolinium and erbium in soil solution and aboveground plant tissue. In these pots concentrations of citric acid in soil solution were significantly higher than in the control. The results show, that low molecular organic acids exuded by plant roots are of great importance for the mobilization of germanium

  4. Allelopathic effect of black mustard tissues and root exudates on some crops and weeds Efeito alelopático de tecidos de mostarda-preta e exsudatos da raiz de algumas culturas e plantas daninhas

    OpenAIRE

    E Al-Sherif; A.K. Hegazy; N.H. Gomaa; Hassan, M O

    2013-01-01

    Laboratory and greenhouse experiments were conducted to evaluate the phytotoxic effect of black mustard extracts and root exudates on two crops: Trifolium alexandrinum and Triticum aestivum, and two weeds: Phalaris paradoxa and Sisymbrium irio. The seeds were treated with aqueous and ethanolic extracts and chloroform for eight days, or subjected to root exudates of just harvested mustard in a greenhouse for five weeks. High-performance liquid chromatography (HPLC) was used to quantify phytoto...

  5. 广藿香根系分泌物的化感自毒作用研究%Study on the Allelopathy and the Autotoxicity of Patchouli Root Exudates

    Institute of Scientific and Technical Information of China (English)

    李玲梅; 李明

    2011-01-01

    以组培苗为材料,应用组织培养技术分析广藿香根系分泌物对萝卜、广金钱草和广藿香组培苗生长的影响.结果表明,广藿香根系分泌物抑制广藿香组培苗和广金钱草的生长;低浓度能促进萝卜生长,高浓度抑制其生长.根系分泌物对广藿香的不利影响随浓度的增加而增大,表明根系分泌物可能是导致广藿香连作障碍的主要原因之一.%The effect of root exudates on the growth of radish, Desmodium styracifoliurn and patchouli tissue culture were analyzed using tissue culture method. Results showed that root exudates of patchouli inhibited the growth of the patchouli tissue culture and Desmodium styracifoliurn;The low concentration of root exudates promoted the growth of the radish, the high concentration of root exudates inhibited the growth of the radish. The greater concentration of root exudates in the medium,the more adverse effect it had on the plants.It is concluded that root exudates of patchouli was one of the important factors inducing continuous cropping obstacle in patchouli.

  6. Ability of Agrogyron elongatum to accumulate the single metal of cadmium, copper, nickel and lead and root exudation of organic acids

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Agrogyron elongatum were grown in nutrient solution containing moderate to high amounts of separate heavy metal of Cd, Cu, Ni and Pb in a greenhouse for a 9-day. Cd, Cu, Ni and Pb generally led to decrease in the elongation of roots although the length of seedlings exposed to Cd and Pb at 0,05 and 0.5 mg/L showed to be slightly greater than that of controls. Of the four metals in the experiment, Pb was absorbed and accumulated to the highest level, with the concentrations of 92754 mg/kg dry weight (DW) in roots and 11683 mg/kg DW in shoots. Cd was moderately accumulated in Agrogyron elongatum, but the maximum bioaccumulation coefficients (BCs) for rpots and shoots were observed. The patterns for Cu and Ni uptake and distribution in plants differed from those of Pb and Cd, as it was showed that the shoot accumulation of Cu and Ni was significantly higher than in roots. A. elongatum had the highest Ni concentration in shoots (30261 mg/kg DW)at the external concentration of 250 mg/L. Cu ranked second, with a shoot concentration of 12230 mg/kg DW when 50 mg/L Cu in solution was applied. For the four trace elements tested, the highest concentrations in shoots decreased by the order of Ni > Cu > Pb > Cd (mg/kg DW),and those in roots were Pb > Cd > Ni > Cu (mg/kg DW). Malic, oxalic and citric acids exuded by roots exposed to 1 and 50 mg/L of the metals were detected. Release of organic acids from plants significantly differed among the metal treatments. Cu was most effectively in inducing rpot exudation of the three types of organic acids. Cd, and Ni were also the inducers of secretion of malic and oxalic acids. With reference of Pb,a small amounts of malic and oxalic acids were detected in the root exudates, but few quantities of citric acid were found. However, no orrelation between alternations in root exudation of organic acids and metal accumulation could be established.

  7. Mycorrhiza alters the profile of root hairs in trifoliate orange.

    Science.gov (United States)

    Wu, Qiang-Sheng; Liu, Chun-Yan; Zhang, De-Jian; Zou, Ying-Ning; He, Xin-Hua; Wu, Qing-Hua

    2016-04-01

    Root hairs and arbuscular mycorrhiza (AM) coexist in root systems for nutrient and water absorption, but the relation between AM and root hairs is poorly known. A pot study was performed to evaluate the effects of four different AM fungi (AMF), namely, Claroideoglomus etunicatum, Diversispora versiformis, Funneliformis mosseae, and Rhizophagus intraradices on root hair development in trifoliate orange (Poncirus trifoliata) seedlings grown in sand. Mycorrhizal seedlings showed significantly higher root hair density than non-mycorrhizal seedlings, irrespective of AMF species. AMF inoculation generally significantly decreased root hair length in the first- and second-order lateral roots but increased it in the third- and fourth-order lateral roots. AMF colonization induced diverse responses in root hair diameter of different order lateral roots. Considerably greater concentrations of phosphorus (P), nitric oxide (NO), glucose, sucrose, indole-3-acetic acid (IAA), and methyl jasmonate (MeJA) were found in roots of AM seedlings than in non-AM seedlings. Levels of P, NO, carbohydrates, IAA, and MeJA in roots were correlated with AM formation and root hair development. These results suggest that AMF could alter the profile of root hairs in trifoliate orange through modulation of physiological activities. F. mosseae, which had the greatest positive effects, could represent an efficient AM fungus for increasing fruit yields or decreasing fertilizer inputs in citrus production. PMID:26499883

  8. AM symbiosis alters phenolic acid content in tomato roots

    OpenAIRE

    López-Ráez, Juan A.; Flors, Victor; García, Juan M.; Pozo, Maria J.

    2010-01-01

    Arbuscular mycorrhizal (AM) fungi colonize the roots of most plants to establish a mutualistic symbiosis leading to important benefits for plant health. We have recently shown that AM symbiosis alters both transcriptional and hormonal profiles in tomato roots, many of these changes related to plant defense. Here, we analytically demonstrate that the levels of other important defense-related compounds as phenolic acids are also altered in the symbiosis. Both caffeic and chlorogenic acid levels...

  9. Allelopathic effect of Commelina benghalensis root exudates%火柴头根系分泌物的化感效应

    Institute of Scientific and Technical Information of China (English)

    杨田甜; 杜海荣; 陈刚; 邓鹏; 甄伟伟

    2011-01-01

    在农田生态系统中,作物晚发弱苗的部分原因是杂草向作物生长周围环境释放化感物质.本研究以疏水性根渗出液连续收集法(C RETS)收集火柴头根系分泌物,在室内采用培养皿滤纸和砂培法分别研究了火柴头根系分泌物对4种常见农作物种子萌发、幼苗生长的化感作用.结果表明:火柴头根系分泌物对高粱、玉米、绿豆和油菜具有不同程度的化感效应,化感效应响应强度由强到弱的顺序为:油菜>玉米>绿豆>高梁.对种子萌发和幼苗生长也存在明显的浓度效应,总体上呈现出低浓度(≤0.025 g·mL-1)促进,高浓度( ≥0.050 g·mL-1)抑制的现象,且随着处理浓度的增加抑制作用逐渐增强.%In the farmland ecosystem, one reason for the crop's postponed seed germination and weak seedling was attributed to the influence of allelochemicals released from the weeds. The root exudates of Commelina benghalensis were collected with a continuous trapping system. The allelopathic effects of the root exudates from Commelina benghalensis L on four crops - Sorghum vulgare, Zea mays, Vigna radiate and Brassica napus were investigated in seed germination and seedling growth with petri-dish and sand cultivation. The results showed that the root exudates from C. benghalensis had different allelopathic effects on the four crops, and varied with crop species in the descending order of Brassica napus > Zea mays > Vigna radiate > Sorghum vulgare. Allelopathic index of seed germination and seedling growth depended on the concentration of root exudates, that is, when the concentration was lower than 0. 025 g.mL-1 , the germination and seedling growth of acceptors were promoted. While the concentration was over 0. 050 g . mL-1~ , they were inhibited, and the level of inhibition was improved with the increase of the root exudates concentration. In conclusion, Brassica napus was inhibited more strongly than the other species at the same

  10. 大蒜根系分泌物对同属作物的抑制作用%Inhibition Effect of Garlic Root Exudates on the Genus Allium

    Institute of Scientific and Technical Information of China (English)

    刘素慧; 刘世琦; 张自坤; 尉辉; 黄治军; 张宇

    2011-01-01

    [Objective] In order to provide a theoretical basis for solving cropping obstacles of garlic, the inhibition of garlic root exudates on the genus Allium was studied. [Method] In order to avoid interferences from external factors, this paper studied the autotoxicity of garlic root exudates on welsh onion, onion and Chinese leek scallion, by using tissue culture under sterilized condition. [Result] Garlic and receptor crops, such as welsh onion, onion and Chinese leek, are belong to the genus Allium. Root exudates of garlic could inhibit the germination and growth of receptor crops, the inhibitory degree increased progressively and significantly with increasing root exudates concentrations of garlic, and the maximal inhibition rates of germination rate, mean time to germination, embryo and radicle length, embryo and embryo fresh weight were 51.72%, 48.20%, 51.57%, 51.57%, 82.14% and 82.29%, respectively. Garlic root exudates decreased root activity of receptor crops, and significant differences were observed except the lowest concentrations (Tl) on welsh onion and onion, compared to control. Compounds involved in the garlic root exudates were isolated and identified by gas chromatography/mass spectrometer (GC-MS), including 2,2'-methylenebis[6-(l,l-dimethylethyl)-4-methyl-Phenol, mono (2-ethylhexyl) phthalate, eicosanoic acid, ferulic acid, 9-hexadecenoic acid, tetradecanoic acid, diallyl disulphide, etc., ferulic acid and myristic acid which had been identified as growth inhibitory substances. [Conclusion] The germination and growth of receptor crops were inhibited by garlic root exudates, which were released to field year by year and could lead to garlic continuous cropping obstacles.%[目的]研究大蒜根系分泌物对同属作物的抑制作用,为解决大蒜连作障碍提供理论依据.[方法]应用组织培养技术,在无菌条件下研究大蒜根系分泌物对同属作物大葱、洋葱和韭菜的毒害作用.[结果]大蒜根系分泌物对3种同

  11. 2,4-diacetylphloroglucinol alters plant root development.

    Science.gov (United States)

    Brazelton, Jessica N; Pfeufer, Emily E; Sweat, Teresa A; Gardener, Brian B McSpadden; Coenen, Catharina

    2008-10-01

    Pseudomonas fluorescens isolates containing the phlD gene can protect crops from root pathogens, at least in part through production of the antibiotic 2,4-diacetylphloroglucinol (DAPG). However, the action mechanisms of DAPG are not fully understood, and effects of this antibiotic on host root systems have not been characterized in detail. DAPG inhibited primary root growth and stimulated lateral root production in tomato seedlings. Roots of the auxin-resistant diageotropica mutant of tomato demonstrated reduced DAPG sensitivity with regards to inhibition of primary root growth and induction of root branching. Additionally, applications of exogenous DAPG, at concentrations previously found in the rhizosphere of plants inoculated with DAPG-producing pseudomonads, inhibited the activation of an auxin-inducible GH3 promoter::luciferase reporter gene construct in transgenic tobacco hypocotyls. In this model system, supernatants of 17 phlD+ P. fluorescens isolates had inhibitory effects on luciferase activity similar to synthetic DAPG. In addition, a phlD() mutant strain, unable to produce DAPG, demonstrated delayed inhibitory effects compared with the parent wild-type strain. These results indicate that DAPG can alter crop root architecture by interacting with an auxin-dependent signaling pathway. PMID:18785830

  12. Graviresponsiveness of surgically altered primary roots of Zea mays

    Science.gov (United States)

    Maimon, E.; Moore, R.

    1991-01-01

    We examined the gravitropic responses of surgically altered primary roots of Zea mays to determine the route by which gravitropic inhibitors move from the root tip to the elongating zone. Horizontally oriented roots, from which a 1-mm-wide girdle of epidermis plus 2-10 layers of cortex were removed from the apex of the elongating zone, curve downward. However, curvature occurred only apical to the girdle. Filling the girdle with mucilage-like material transmits curvature beyond the girdle. Vertically oriented roots with a half-girdle' (i.e. the epidermis and 2-10 layers of the cortex removed from half of the circumference of the apex of the elongating zone) curve away from the girdle. Inserting the half-girdle at the base of the elongating zone induces curvature towards the girdle. Filling the half-circumference girdles with mucilage-like material reduced curvature significantly. Stripping the epidermis and outer 2-5 layers of cortex from the terminal 1.5 cm of one side of a primary root induces curvature towards the cut, irrespective of the root's orientation to gravity. This effect is not due to desiccation since treated roots submerged in water also curved towards their cut surface. Coating a root's cut surface with a mucilage-like substance minimizes curvature. These results suggest that the outer cell-layers of the root, especially the epidermis, play an important role in root gravicurvature, and the gravitropic signals emanating from the root tip can move apoplastically through mucilage.

  13. 嫁接西瓜根系分泌物的化感效应及其化感物质的鉴定%Allelopathic effects and identification of allelochemicals in root exudates of grafted watermelons

    Institute of Scientific and Technical Information of China (English)

    郑阳霞; 唐海东; 李焕秀; 严泽生; 郭学君

    2011-01-01

    In order to study the allelopathic effects of root exudates from the watermelons grafted with pumpkin and calabash as rootstocks,effects of root exudates from the watermelons grafted on the seed germination and seedling growth of watermelons were researched.The Allelochemicals of root exudates were detected by GC-MS.The results showed that the seed germination and seedling growth of watermelons were increased when the root exudates were in low concentration,but decreased in high concentration.The root exudates promoted the seed germination and seedling growth of watermelons at 2.5 μL·L-1.The root exudates began to restrain the seed germination and seedling growth of watermelons at 10 μL·L-1.When the concentrations were lower,the root exudates from grafted watermelons had more effects on the seed germination and seedling vegetal promotion than own-rooted watermelons.The inhibiting effect of grafted watermelons was less than that of own-rooted watermelon at high concentration of root exudates.And the identification of the allelochemicals in root exudates of grafted watermelons indicated that the categories and the relative contents were different from the own-root plants.The results showed that grafting changed the categories and the relative contents of root exudate components and changed allelopathic effects.Furthermore,there was obvious grafting superiority.So grafting was one of the effective methods for relieving the continuous cropping obstacles caused by autotoxicity.%为了研究嫁接西瓜根系分泌物的化感效应,采用南瓜、葫芦作砧木嫁接西瓜,研究了嫁接西瓜根系分泌物对西瓜种子萌发和幼苗生长的影响,并对嫁接西瓜根系分泌物中的化感物质进行了GC-MS检测。结果表明,各处理对西瓜种子发芽和幼苗生长均呈现出低促高抑的规律。在根系分泌物浓缩液浓度为2.5μL.L-1时,促进西瓜种子的发芽和幼苗的生长。在浓度为10μL.L-1、20μL.L-1

  14. Modeling of Nonlinear Dynamics and Synchronized Oscillations of Microbial Populations, Carbon and Oxygen Concentrations, Induced by Root Exudation in the Rhizosphere

    Science.gov (United States)

    Molz, F. J.; Faybishenko, B.; Jenkins, E. W.

    2012-12-01

    Mass and energy fluxes within the soil-plant-atmosphere continuum are highly coupled and inherently nonlinear. The main focus of this presentation is to demonstrate the results of numerical modeling of a system of 4 coupled, nonlinear ordinary differential equations (ODEs), which are used to describe the long-term, rhizosphere processes of soil microbial dynamics, including the competition between nitrogen-fixing bacteria and those unable to fix nitrogen, along with substrate concentration (nutrient supply) and oxygen concentration. Modeling results demonstrate the synchronized patterns of temporal oscillations of competing microbial populations, which are affected by carbon and oxygen concentrations. The temporal dynamics and amplitude of the root exudation process serve as a driving force for microbial and geochemical phenomena, and lead to the development of the Gompetzian dynamics, synchronized oscillations, and phase-space attractors of microbial populations and carbon and oxygen concentrations. The nonlinear dynamic analysis of time series concentrations from the solution of the ODEs was used to identify several types of phase-space attractors, which appear to be dependent on the parameters of the exudation function and Monod kinetic parameters. This phase space analysis was conducted by means of assessing the global and local embedding dimensions, correlation time, capacity and correlation dimensions, and Lyapunov exponents of the calculated model variables defining the phase space. Such results can be used for planning experimental and theoretical studies of biogeochemical processes in the fields of plant nutrition, phyto- and bio-remediation, and other ecological areas.

  15. IDENTIFITION AND STUDY ON ALLELOPATHY OF SOYBEAN ROOT EXUDATES%大豆根分泌物的鉴定及其化感作用的初步研究

    Institute of Scientific and Technical Information of China (English)

    韩丽梅; 李国权

    2000-01-01

    采用GC-MS分析法,鉴定了由水培试验方法获得的2周、8周大豆根分泌物的二氯甲烷提取物,并对其化感作用进行了初步研究。结果表明:能被二氯甲烷提取出来的根分泌物有有机酸类、醇类、酯类、酮类、醛类、酚类、苯类、烃类等有机化合物,其中包含一些资料报道过的化感物质。与对照比较,2周、8周大豆根分泌物对大豆种子萌发、8周根分泌物对胚根生长未表现出显著抑制作用,但2周根分泌物对胚根生长却表现出极显著的化感抑制作用。上述结果表明,大豆根分泌物中存在化感物质,2周与8周大豆根分泌物的种类和数量有所不同。本文还探讨了大豆根分泌物的化感作用及大豆根分泌物与大豆连作障碍的关系等问题。%Compounds extracted with dichloromethane from soybean rootexudates for two weeks, eight weeks in water-culture were identified and allelopathy were studied by GC-MS analysis. The results showed that: The soybean root exudates extracted with dichloromethane included organic acide, alcohol, ester, acetone, aldehyde, phenol, pheyl, hydrocarbon and so on. Many of which were reported as allelochemicale. Contrast with control, the influence of the soybean root exudates for two weeks, eight weeks on the germination of soybean seeds, for eight weeks on radicle growth did not show significant allelopathy inhibition. But the allelopathy of the soybean root exudates for two weeks on soybean radicle growth showed significant inhibition. The results showed that the allelochemicals exist in the soybean root exudates. The varieties and quantities of soypean root exudates for two weeks are different with those for eight weeks. In addition, the alleleopathy of soybean root exudates and the relationship between soybean root exudates and barrier on soybean continuous and alternate cropping were discussed.

  16. 铝对茶树根细胞膜透性和根系分泌有机酸的影响%Impacts of Aluminum on Root Cell Membrane Permeability and Organic Acids in Root Exudates of Tea Plant

    Institute of Scientific and Technical Information of China (English)

    刘腾腾; 郜红建; 宛晓春; 张正竹

    2011-01-01

    采用溶液培养法研究了铝浓度对茶树根细胞膜透性和分泌低分子量有机酸的影响.结果表明,低质量浓度铝( 20 mg/L)有利于茶树根细胞膜的稳定,缺铝(0 mg/L,CK)和高铝(100 mg/L)均使根细胞膜透性显著降低.有机酸总量随铝浓度升高呈现先降低后升高的趋势.草酸、苹果酸和柠檬酸是茶树根系分泌的3种主要有机酸,占85%~93%;根系分泌草酸的量与对照相比,低铝和高铝时显著降低了84.7%和34.3%;分泌苹果酸的量与对照相比,低铝时增加了121.0%,高铝时降低了40.9%;铝浓度对柠檬酸的分泌量影响不大.研究结果可为阐明茶树根系的耐铝生理机制提供依据.%The impacts of aluminum (Al) concentration on root cell membrane permeability and components of organic acids in root exudates of tea plant (Camellia, sinensis L.) were investigated by hydroponics. Results showed that 20 mg/L of low Al concentration could enhance the cell membrane stability of tea root, and the membrane permeability was significantly declined with deficiency Al (0 mg/L, CK) and high Al (100 mg/L) treatments. The total organic acids firstly decreased and then increased with the increase of Al concentrations. About 85%~93% of the total organic acids in root exudates of tea plant were oxalic acid, malic acid and citric acid. Compared with CK, the oxalic acid secretion remarkably reduced 84.7% and 34.3% under the low and high Al concentration treatments. Compared with CK, the malic acid of root exudates increased by 121.1% in low Al concentration, and decreased by 40.9% in high Al concentration. There wasn't significant influence on citric acid, containing about 3.5~4.5 mg/g. This result can provide critical data for elucidating tolerance mechanisms of Al stress on tea root.

  17. 3种水培植物根系分泌的有机酸对氮循环菌的影响%Effect of organic acids exuded from hydroponic plants roots on nitrogen cycling bacteria

    Institute of Scientific and Technical Information of China (English)

    朱静平; 程凯

    2011-01-01

    通过收集水培吊兰、空心菜和水芹的根系分泌物,采用液相色谱分析了其中有机酸的种类和含量;并研究了根系分泌物中的有机酸对氮循环菌的影响。结果表明3,种植物根系分泌物中的有机酸对氨化细菌和反硝化细菌的生长具有促进作用,对亚硝化细菌和硝化细菌的生长具有抑制作用。%The variety and content of organic acids exuded from hydroponic Chlorophytum comosum roots,hydroponic Ipomoea aquatica roots and hydroponic Oenanthe javanica roots by liquid chromatography were studied,and the effects of organic acid of root exudates on nitrogen cycling bacteria were analysed.The results showed that organic acid of the three hydroponic plants root exudates has promotion effect on ammonifying bacteria and denitrifying bacteria,but has inhibition effect on nitrobacteria and nitrosobacteria.

  18. Inhibitory potential of naphthoquinones leached from leaves and exuded from roots of the invasive plant Impatiens glandulifera.

    Science.gov (United States)

    Ruckli, Regina; Hesse, Katharina; Glauser, Gaetan; Rusterholz, Hans-Peter; Baur, Bruno

    2014-04-01

    Exploring the effects of allelopathic plant chemicals on the growth of native vegetation is essential to understand their ecological roles and importance in exotic plant invasion. Naphthoquinones have been identified as potential growth inhibitors produced by Impatiens glandulifera, an exotic annual plant that recently invaded temperate forests in Europe. However, naphthoquinone release and inhibitory potential have not been examined. We quantified the naphthoquinone content in cotyledons, leaves, stems, and roots from plants of different ages of both the invasive I. glandulifera and native Impatiens noli-tangere as well as in soil extracts and rainwater rinsed from leaves of either plant species by using ultra-high pressure liquid chromatography-mass spectrometry (UHPLC-MS). We identified the compound 2-methoxy-1,4-naphthoquinone (2-MNQ) exclusively in plant organs of I. glandulifera, in resin bags buried into the soil of patches invaded by I. glandulifera, and in rainwater rinsed from its leaves. This indicates that 2-MNQ is released from the roots of I. glandulifera and leached from its leaves by rain. Specific bioassays using aqueous shoot and root extracts revealed a strong inhibitory effect on the germination of two native forest herbs and on the mycelium growth of three ectomycorrhiza fungi. These findings suggest that the release of 2-MNQ may contribute to the invasion success of I. glandulifera and support the novel weapons hypothesis. PMID:24722883

  19. Effects of Root Exudates from Helianthus annuus on Adsorption of Cd~(2+) on Yellow Earth%向日葵根分泌物对黄壤吸附Cd~(2+)行为的影响

    Institute of Scientific and Technical Information of China (English)

    张道勇; 潘响亮; 黄承玲

    2009-01-01

    从pH的影响、等温吸附、吸附动力学和热动力学4个方面研究了向日葵根分泌物对黄壤吸附Cd~(2+)的行为的影响.随着pH的升高,黄壤对Cd~(2+)的吸附量都升高,而且在pH为3~8的范围内,根分泌物的存在都减少了黄壤对Cd~(2+)的吸附.不论有否根分泌物存在,Langmuir方程和Freundlich方程能满意地描述黄壤对Cd~(2+)的等温吸附行为,黄壤对镉的吸附动力学符合拟二级速率方程,是一个墒减的放热的自发反应.向日葵根分泌物的存在抑制了黄壤对镉的吸附容量和吸附速率,并一定程度上降低了吸附过程的自发性.%The effects of root exudates from Helianthus annuus on Cd~(2+) adsorption to yellow earth were investigated in the present study. It was found that root exudates generally inhibited adsorption of Cd~(2+) onto yellow earth. Cd~(2+) adsorption capacity increased on increasing of solution pH and the presence of root exudates reduced Cd~(2+) adsorption capacity at pH 3 - 8-Cd~(2+) isothermal adsorption could be well represented with both Langmuir and Freundlich equations, and the adsorption kinetics with pseudo-second order equation. Cd~(2+) adsorption capacity to yellow earth is a spontaneous exothermic reaction.The presence of root exudates reduced the adsorption capacity and adsorption rate.

  20. Allelopathy effects of Panax notoginseng root exudates on wheat under different nitrogen levels%不同氮素水平下三七根系分泌物对小麦的化感作用

    Institute of Scientific and Technical Information of China (English)

    拱健婷; 张子龙; 王雄飞

    2014-01-01

    In ordre to explore the allelopathy effect of Panax notoginseng root exudates under different nitrogen levels, the present study using Panax notoginseng seedlings and wheat plants as donor and receptor plants , respectively, was carried out.The results showed that Panax notoginseng root exudates exhibited inhibitory effect on wheat (M3 =-0.04).Compared with seedling growth, seed germination was more likely to be inhibited by the allelopathy effect of Panax notoginseng root exudates.With increased N level, the inhibitory effect on germination index increased in the order of excess N >normal N >deficient N.The shoot growth of wheat seedling was enhanced by allelopathy effect of Panax notoginseng root exudates, while the root growth was inhibited.Besides, it was noticed that the allelopathy effect of Panax notoginseng root exudates on wheat was related to the nitrogen level in solution.%为探讨三七在不同氮素水平下根系分泌物的化感作用,以三七种苗为供体植物,小麦为受体植物进行生物测定。结果表明,三七根系分泌物对小麦表现出化感抑制作用(敏感指数M3=-0.04)。从发育时期来看,小麦种子萌发阶段较幼苗生长阶段更易受化感抑制作用影响,且其发芽指数受抑程度随氮素水平的升高而逐渐增强,即过氮>正常>缺氮;在小麦幼苗生长阶段,三七根系分泌物对其地上部化感作用以促进为主,对根部生长则以抑制作用为主;且三七根系分泌物对小麦的化感作用与培养液氮素水平有关。

  1. Proteomic alterations in root tips of Arabidopsis thaliana seedlings under altered gravity conditions

    Science.gov (United States)

    Zheng, H. Q.; Wang, H.

    Gravity has a profound influence on plant growth and development Removed the influence of gravitational acceleration by spaceflight caused a wide range of cellular changes in plant Whole seedling that germinated and grown on clinostats showed the absent of gravitropism At the cellular level clinostat treatment has specific effects on plant cells such as induce alterations in cell wall composition increase production of heat-soluble proteins impact on the cellular energy metabolism facilitate a uniform distribution of plastids amyloplasts and increase number and volume of nucleoli A number of recent studies have shown that the exposure of Arabidopsis seedlings and callus cells to gravity stimulation hyper g-forces or clinostat rotation induces alterations in gene expression In our previous study the proteome of the Arabidopsis thaliana callus cells were separated by high resolution two-dimensional electrophoresis 2-DE Image analysis revealed that 80 protein spots showed quantitative and qualitative variations after exposure to clinostat rotation treatment We report here a systematic proteomic approach to investigate the altered gravity responsive proteins in root tip of Arabidopsis thaliana cv Landsberg erecta Three-day-old seedlings were exposed for 12h to a horizontal clinostat rotation H simulated weightlessness altered g-forces by centrifugation 7g hypergravity a vertical clinostat rotation V clinostat control or a stationary control grown conditions Total proteins of roots were extracted

  2. Rhizosphere water dynamics: role of exudates in mediating water retention and flow characteristics

    Science.gov (United States)

    Albalasmeh, Ammar; Ghezzehei, Teamrat

    2013-04-01

    In recent years, significant amount of literature showed that rhizosphere's physical and chemical properties markedly differ from those of the bulk soil. Plants invest large portion of their photosynthetic carbon in developing root architecture that optimally exploits water and nutrient distributions in the soil. There is indirect evidence suggesting that these exudates play a major role in altering the of the soil water retention properties. In this study, we investigated the role of root exudates on rhizosphere water dynamics using analog system. Glass beads were used to represent loose soil and dilute solutions of polygalacutronic acid (PGA) to mimic exudates (0, 1, 5, 15 and 29 g/L). The samples were subjected to periods of drying and subsequent equilibration. At each stage, the water potential was measured using WP4C Dewpoint PotentiaMeter. On the other hand, sand samples were saturated with PGA at the same concentration used to study the effect of exudates on water evaporation rate. The effect of root exudates on soil water retention can be attributed to at least two factors. The most widely speculated effect is through enhanced of soil aggregation. This effect is primarily due to capillary adhesion in fine pores within aggregates and is consistent with visual observation of pronounced aggregation in many rhizosphere soils. The second factor is related to osmotic effect of the exudate solution. Our observations show that the capillary effect is mostly limited to higher water potential regime (> -1 bar suction). Whereas the osmotic effect dominates in <- 1 bar suction. At the same time, the osmotic potential results from these organic exudates play an important role in reducing the evaporation rate. These results will provide direct quantitative evidence of how rhizosphere organic matter helps plant-soil relations.

  3. GC-MS identification of chemicals in lily root exudates%百合根系分泌物的GC-MS鉴定

    Institute of Scientific and Technical Information of China (English)

    程智慧; 徐鹏

    2012-01-01

    【目的】分析百合根系分泌物中的主要物质,为预防百合连作障碍和建立科学栽培制度提供依据。【方法】分别用石油醚、乙醚、乙酸乙酯、氯仿和甲醇分离水培法收集百合根系分泌物,用GC-MS分析经生物检测化感强势组分(甲醇组分、石油醚组分、氯仿组分)中的有机物质。【结果】按照相似度达80%、相对含量达0.20%分析检出物质,从百合根系分泌物甲醇组分中共检出11种物质,主要为苯甲酸酯类衍生物,如邻苯二甲酸二异辛酯(52.11%)和双-2-乙己基邻苯二甲酸酯(40.95%),其他成分含量均在1%以下;从石油醚组分中检出6种苯甲酸酯类衍生物,如邻苯二甲酸二异辛酯(88.04%)、邻苯二甲酸二丁酯(9.06%),其他成分含量均在1%以下;氯仿组分中有机物质丰富,检出的有酯类、醛、酚、烯烃、烷烃等19种,含量在1%以上的有邻苯二甲酸二异辛酯(39.87%)、双-2-乙己基邻苯二甲酸酯(39.62%)、十六烷(1.36%)、2-甲氧基-1-(2-硝乙烯基)-3-苯甲氧基-苯(1.22%)、2,4-二叔丁基苯酚(1.02%)。百合根系分泌物的乙醚和乙酸乙酯组分化感作用不强,未对其中的有机物质做进一步鉴定。【结论】百合根系分泌物的GC-MS检出物主要为酯类物质,不同组分中含量高的均为苯甲酸酯类衍生物,还有少量醛、酚、烯等。%【Objective】 The study was to investigate the main organic chemicals in lily root exudates to provide scientific basis for preventing of continuous cropping obstacles and establishing of lily cropping system.【Method】 Lily root exudates collected by hydroponic culture of lily bulbs was isolated with petroleum ether,diethyl ether,ethyl acetate,chloroform and methanol respectively.The strong allelopathic components selected by bioassay were identified by GC-MS.【Result】 Based on the standard of similar degree no lower than 80% and relative content no

  4. Fluidity of pea root plasma membranes under altered gravity

    Science.gov (United States)

    Klymchuk, D. O.; Baranenko, V. V.; Vorobyova, T. V.; Dubovoy, V. D.

    This investigation aims to determine whether clinorotation 2 rev min of pea Pisum sativum L seedlings induces the alterations in the physical-chemical properties of cellular membranes including the plasma membrane fluidity The last is an important regulator of functional activity of membrane enzymes The plasma membranes were isolated by aqueous two-phase partitioning from roots of 6-day old pea seedlings The membrane fluidity was examined by fluorescence spectroscopy using pyrene probe The plasma membrane vesicles with known protein concentration were added to the incubation buffer to a final concentration of 50 mu g of protein per ml A small amount by 1 mu l of pyrene solution in 2-propanol was added to the incubation mixture to a final probe concentration 5 mu M at constant mixing Fluorescence spectra were measured using a Perkin-Elmer LS-50 spectrofluorometer Perkin-Elmer England Pyrene was excited at 337 nm and fluorescence intensity of monomers I M and excimers I E were measured at 393 and 470 nm respectively The I E I M ratios were 0 081 pm 0 003 and 0 072 pm 0 004 in preparations obtained from clinorotated and the control seedlings respectively This fact indicates that rotation on the clinostat increases the membrane fluidity Compared with controls clinorotated seedlings have also showed a reduced growth and a higher level of total unsaturated fatty acids determined by gas chromatography The factors that influence on the fluidity of membrane lipids in bilayer appear to be the

  5. Effectively managing wound exudate.

    Science.gov (United States)

    Chamanga, Edwin

    2015-09-01

    The management of wound exudate remains a clinical challenge despite technological advances in products with better exudate-handling capacities. This clinical challenge is occasionally encountered when thick exudate (viscous exudate) is present, and when most modern dressings do not possess the capabilities to manage the viscosity while enabling exudate absorption. Maceration to the peri-wound area poses another challenge, irrespective of the number of topical barrier application products on the market and the innovation of dressing products that lock exudate away or those that encourage vertical wicking. In addition to all the above, in clinical practice, the assessment and documentation of wound exudate remains sporadic, leading to the challenges of effective wound exudate dressing selection and cost-effective dressings. PMID:26322408

  6. Genotypic variation in the ability of landraces and commercial cereal varieties to avoid manganese deficiency in soils with limited manganese availability: is there a role for root-exuded phytases?

    Science.gov (United States)

    George, Timothy S; French, Andrew S; Brown, Lawrie K; Karley, Alison J; White, Philip J; Ramsay, Luke; Daniell, Tim J

    2014-07-01

    The marginal agricultural-systems of the Machair in the Western Isles of Scotland often have limited micronutrient availability because of alkaline soils. Traditional landraces of oats, barley and rye are thought to be better adapted to cope with the limited manganese (Mn) availability of these soils. When commercial cultivars are grown on the Machair, limited Mn-availability reduces crop yield and quality. We hypothesised that traditional cereal landraces selected on the Machair acquire Mn more effectively and that this could be linked to exudation of phytase from roots which would release Mn complexed with inositol phosphates. Growth and Mn-acquisition of five landraces and three commercial cultivars of barley and oats were determined in Machair soil. In addition, root phytase activities were assayed under Mn-starvation and sufficiency in hydroponics. In Machair soil, landraces had greater capacity for acquiring Mn and a greater ability to achieve maximum yield compared to the commercial cultivars. Under Mn-starvation, root phytase exudation was upregulated in all plants, suggesting that this trait might allow cereals to acquire more Mn when Mn-availability is limited. In the landraces, exuded phytase activity related positively to relative Mn-accumulation, whereas in the commercial cultivars this relationship was negative, suggesting that this trait may be secondary to an efficiency trait that has been lost from commercial germplasm by breeding. This research shows that cereal landraces possess traits that could be useful for improving the Mn-acquisition of commercial varieties. Exploiting the genetic diversity of landraces could improve the sustainability of agriculture on marginal calcareous lands globally. PMID:24438182

  7. Allelopathic effect of black mustard tissues and root exudates on some crops and weeds Efeito alelopático de tecidos de mostarda-preta e exsudatos da raiz de algumas culturas e plantas daninhas

    Directory of Open Access Journals (Sweden)

    E Al-Sherif

    2013-03-01

    Full Text Available Laboratory and greenhouse experiments were conducted to evaluate the phytotoxic effect of black mustard extracts and root exudates on two crops: Trifolium alexandrinum and Triticum aestivum, and two weeds: Phalaris paradoxa and Sisymbrium irio. The seeds were treated with aqueous and ethanolic extracts and chloroform for eight days, or subjected to root exudates of just harvested mustard in a greenhouse for five weeks. High-performance liquid chromatography (HPLC was used to quantify phytotoxins from plant tissues. Seed germination of P. paradoxa was reduced with the lowest concentration of the different extracts. However, the aqueous extract at 4% completely curtailed the germination of all the target species. In general, plant extracts had a concentration-dependent reduction of seedling growth of the target species. However, the ethanolic extract, at the lowest concentration, has stimulated the shoot length of both T. alexandrinum and T. aestivum, and the root length of the former. Mustard root exudates inhibited emergence and growth of the target species throughout the experiment. Ferulic and syringic acids were the dominant allelochemicals found when HPLC was used.Experimentos de laboratório e estufa foram realizados para avaliar o efeito fitotóxico dos extratos de mostarda-preta e exsudatos de raiz de duas culturas: Trifolium alexandrinum e Triticum aestivum, bem como de duas plantas daninhas: Phalaris paradoxa e Sisymbrium irio. As sementes foram tratadas com extratos aquosos, etanólicos e clorofórmio por oito dias, ou submetidas a exsudatos de raiz de mostarda recém-colhidaem estufa durante cinco semanas. A cromatografia líquida de alto desempenho (HPLC foi usada para a quantificação de fitotoxinas a partir de tecidos de plantas. Sementes de P. paradoxa apresentam germinação reduzida com a menor concentração dos diferentes extratos. No entanto, o extrato aquoso a 4% restringiu completamente a germinação de todas as esp

  8. Evaluation of the anatomical alterations of lower molars mesial root?s apical third

    Directory of Open Access Journals (Sweden)

    FRÖNER Izabel Cristina

    1999-01-01

    Full Text Available The anatomical apex of the mesial root of the lower molars presents a morphological complexity related to the number and shape of the root canals as well as of the apical foramen and isthmus presence. The knowledge of the complexity of the endodontic system of the molar root area is essencial to select more carefully the best instrumentation and obturation technique, to obtain a more successful endodontic therapy.

  9. Plant exudates promote PCB degradation by a rhodococcal rhizobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Toussaint, Jean-Patrick; Pham, Thi Thanh My; Barriault, Diane; Sylvestre, Michel [Instiut National de la Recherche Scientifique INRS, Laval, QC (Canada). Inst. Armand-Frappier

    2012-09-15

    Rhodococcus erythropolis U23A is a polychlorinated biphenyl (PCB)-degrading bacterium isolated from the rhizosphere of plants grown on a PCB-contaminated soil. Strain U23A bphA exhibited 99% identity with bphA1 of Rhodococcus globerulus P6. We grew Arabidopsis thaliana in a hydroponic axenic system, collected, and concentrated the plant secondary metabolite-containing root exudates. Strain U23A exhibited a chemotactic response toward these root exudates. In a root colonizing assay, the number of cells of strain U23A associated to the plant roots (5.7 x 105 CFU g{sup -1}) was greater than the number remaining in the surrounding sand (4.5 x 104 CFU g{sup -1}). Furthermore, the exudates could support the growth of strain U23A. In a resting cell suspension assay, cells grown in a minimal medium containing Arabidopsis root exudates as sole growth substrate were able to metabolize 2,3,4'- and 2,3',4-trichlorobiphenyl. However, no significant degradation of any of congeners was observed for control cells grown on Luria-Bertani medium. Although strain U23A was unable to grow on any of the flavonoids identified in root exudates, biphenyl-induced cells metabolized flavanone, one of the major root exudate components. In addition, when used as co-substrate with sodium acetate, flavanone was as efficient as biphenyl to induce the biphenyl catabolic pathway of strain U23A. Together, these data provide supporting evidence that some rhodococci can live in soil in close association with plant roots and that root exudates can support their growth and trigger their PCB-degrading ability. This suggests that, like the flagellated Gram-negative bacteria, non-flagellated rhodococci may also play a key role in the degradation of persistent pollutants. (orig.)

  10. 镉超富集植物东南景天根系分泌物的代谢组学研究%Metabonomics Study on Root Exudates of Cd Hyperaccumulator Sedum Alfredii

    Institute of Scientific and Technical Information of China (English)

    罗庆; 孙丽娜; 胡筱敏

    2015-01-01

    利用基于气相色谱_质谱联用技术( GC_MS)的代谢组学方法,寻找不同处理条件间差异显著的镉超富集植物东南景天根系分泌物质,并探讨它们对东南景天耐受或超富集镉的可能作用机制。收集0和40μmol/L镉分别处理4和8天后的东南景天根系分泌物样品,通过样品冻干、甲醇溶解、甲氧胺盐酸盐和N_甲基_N_(三甲基硅烷)三氟乙酰胺衍生化处理、GC_MS检测的分析过程,得到根系分泌物的表达谱。主成分分析和正交偏最小二乘判别分析( OPLS_DA)得分图可将不同处理条件间东南景天的根系分泌物质明显区分,运用OPLS_DA载荷图、模型的变量重要性因子和方差分析发现12个根系分泌物质在4组间存在显著性差异。它们的相对含量在不同处理条件间的变化趋势明显不同,表明东南景天可通过调节它们的分泌来耐受或超富集重金属镉。%A metabonomics method based on gas chromatography_mass spectrometry ( GC_MS) was developed for detecting the significant differences of root exudates of the Cd hyperaccumulator Sedum alfredii under different treatments and study the effect mechanism of S. alfredii tolerating or accumulating the heavy metal Cd. The root exudates were collected after treatment for 4 and 8 days with 0 and 40μmol/L Cd. The collected solution was lyophilized and dissolved with methanol, and after derivatization with methoxyamine hydrochloride and N_methyl_N_trifluoroacetamide, the samples were analyzed by GC_MS. Principal component analysis ( PCA) and orthogonal partial least_squares discrimination analysis ( OPLS_DA) were carried out for pattern recognition and a clear separation among the different treatments was achieved. Twelve compounds which caused the separation among the different treatments were found and identified. With the change of treatments, the relative amount of these 12 compounds revealed different trends, which indicated that the Cd

  11. 大蒜根系分泌物化感作用及化感物质的比较%Comparative analysis of allelopathy and allelochemicals of the root exudates in garlic

    Institute of Scientific and Technical Information of China (English)

    周艳丽; 程智慧

    2012-01-01

    【目的】利用生物测定和GC-MS分析方法,研究大蒜根系分泌物的化感作用及化感物质。【方法】采用琼脂培和砂培2种栽培方式收集大蒜根系分泌物,分别采用乙醚、乙酸乙酯、三氯甲烷和正丁醇4种有机溶剂进行萃取分离,对各有机溶剂萃取液进行萝卜种子发芽试验,确定出强化感作用组分,并对其成分进行GC-MS分析。【结果】各有机溶剂萃取液的化感作用强弱顺序依次为:乙酸乙酯萃取液〉三氯甲烷萃取液〉正丁醇和乙醚萃取液,初步确定大蒜根系分泌物中的化感物质为2,6-二异丙基苯酚、2,6-二叔丁基对甲酚和二烯丙基二硫醚。【结论】2种栽培方式收集的大蒜根系分泌物的乙酸乙酯组分中的成分相似,但在含量上差异较大,表现为砂培〉琼脂培。%【Objective】 The allelopathy and major allelochemicals in root exudates of garlic were studied by bioassay and GC-MS methods.【Method】 The root exudates of garlic were collected from agar culture and sand culture in this experiment,and were extracted by ethyl ether,ethyl acetate,chloroform and n-butanol.【Result】 The results showed that allelopathy of ethyl acetate component was the strongest,followed by chloroform component,the allelopathy of ethyl ether component and n-butanol component.The component of ethyl acetate was analyzed by GC-MS,and the main allelochemicals were identified as 2,6-bis(1-methylethyl)-phenol,butylated hydroxytoluene and diallyl disulphide.【Conclusion】 The allelochemicals were similar in ethyl acetate fraction of two cultivation forms,but the quantity was different,and the varieties and quantities of allelochemicals in sand culture were higher than agar culture.

  12. Exogenous gibberellin altered morphology, anatomic and transcriptional regulatory networks of hormones in carrot root and shoot

    OpenAIRE

    Wang, Guang-Long; Que, Feng; Xu, Zhi-Sheng; Wang, Feng; Xiong, Ai-Sheng

    2015-01-01

    Background Gibberellins stimulate cell elongation and expansion during plant growth and development. Carrot is a root plant with great value and undergoes obvious alteration in organ size over the period of plant growth. However, the roles of gibberellins in carrot remain unclear. Results To investigate the effects of gibberelliins on the growth of carrot, we treated carrot plants with gibberellic acid 3 (GA3) or paclobutrazol (a gibberellin inhibitor). The results found that GA3 dramatically...

  13. Nature's amazing biopolymer: basic mechanical and hydrological properties of soil affected by plant exudates

    Science.gov (United States)

    Naveed, Muhammad; Roose, Tiina; Raffan, Annette; George, Timothy; Bengough, Glyn; Brown, Lawrie; Keyes, Sam; Daly, Keith; Hallett, Paul

    2016-04-01

    Plant exudates are known to have a very large impact on soil physical properties through changes in mechanical and hydrological processes driven by long-chain polysaccharides and surface active compounds. Whilst these impacts are well known, the basic physical properties of these exudates have only been reported in a small number of studies. We present data for exudates obtained from barley roots and chia seeds, incorporating treatments examining biological decomposition of the exudates. When these exudates were added to a sandy loam soil, contact angle and drop penetration time increased exponentially with increasing exudate concentration. These wetting properties were strongly correlated with both exudate density and zero-shear viscosity, but not with exudate surface tension. Water holding capacity and water repellency of exudate mixed soil tremendously increased with exudate concentration, however they were significantly reduced on decomposition when measured after 14 days of incubation at 16C. Mechanical stability greatly increased with increasing exudate amendment to soils, which was assessed using a rheological amplitude sweep test near saturation, at -50 cm matric potential (field capacity) using indentation test, and at air-dry condition using the Brazilian test. This reflects that exudates not only attenuate plant water stress but also impart mechanical stability to the rhizosphere. These data are highly relevant to the understanding and modelling of rhizosphere development, which is the next phase of our research.

  14. PAEs胁迫对高/低累积品种水稻根系形态及根系分泌低分子有机酸的影响%Effects of PAE Stress on Root Morphology andLow Molecular Weight Organic Acid (LMWOC) in Root Exudates of Rice (Oryza sativa L.) Cultivars with High- and Low-PAE Accumulation

    Institute of Scientific and Technical Information of China (English)

    陈桐; 蔡全英; 吴启堂; 吕辉雄; 曾巧云; 李慧

    2015-01-01

    systems contaminated with PAEs (0, 20, 40, and 80 mg·L-1). Plant samples were collected at tillering and jointing stage, root morphological properties were analyzed by root scanner, low molecular weight organic acids in root exudates were determined by HPLC, and di(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) in roots, stems, and leaves of rice were analyzed using gas chromatography coupled with mass spectrometry (GC/MS). The responses of root morphological characteristics (including total root length, root surface area, and root volume) and low molecular weight organic acid (LMWOC) in root exudates were analyzed to investigate the variation factors of high- and low-PAE accumulation of rice cultivars. The results show that, with the increase of PAE concentrations in solution, total root length, root surface area, and root volume of two cultivars increased firstly and then decreased. In the same PAE concentration, root morphological parameters of cultivar Peizataifeng were generally higher than cultivar Fengyousimiao. Change of PAE concentrations in solution was a key factor affecting early growth differences in root morphology of the two rice cultivars. PAE concentrations in the plants of two cultivars increased with PAE concentrations in solution, and those of cultivar Peizataifeng were also higher than cultivar Fengyousimiao. The concentrations of DEHP and DBP in different tissues decrease in the order of roots>leaves≥stems. At tillering stage, PAE concentrations in the plants of two cultivars were significantly correlated with PAE concentrations in solution, but poorly correlated at jointing stage. LMWOC concentrations in root exudates of two cultivars displayed different change trends with PAE concentrations in solution, but concentrations of oxalic acid increased (ranging from 1.11 to 8.13 mg·L-1). Moreover, concentrations of oxalic acid were significantly positively correlated with the concentrations of DBP and DEHP in roots. These results

  15. Striga seed-germination activity of root exudates and compounds present in stems of Striga host and nonhost (trap crop) plants is reduced due to root colonization by arbuscular mycorrhizal fungi.

    OpenAIRE

    Lendzemo, V.W.; Kuyper, T. W.; Vierheilig, H.

    2009-01-01

    Root colonization by arbuscular mycorrhizal (AM) fungi reduces stimulation of seed germination of the plant parasite Striga (Orobanchaceae). This reduction can affect not only host plants for Striga, resulting in a lower parasite incidence, but also false hosts or trap crops, which induce suicidal Striga seed germination, thereby diminishing their effectiveness. In order to better understand these AM-induced effects, we tested the influence of root colonization by different AM fungi on the se...

  16. Effects of Chinese onion's root exudates on cucumber seedlings growth and rhizosphere soil microorganisms%分蘖洋葱根系分泌物对黄瓜幼苗生长及根际土壤微生物的影响

    Institute of Scientific and Technical Information of China (English)

    杨阳; 刘守伟; 潘凯; 吴凤芝

    2013-01-01

    以不同化感潜力分蘖洋葱为供体,黄瓜为受体,研究了分蘖洋葱根系分泌物对黄瓜幼苗生长、根际土壤微生物数量及细菌群落结构的影响.结果表明:不同化感潜力分蘖洋葱根系分泌物对黄瓜幼苗生长均具有促进作用,且随着浓度的升高,促进作用增强,相同浓度下,化感潜力强、弱供体之间差异不显著;不同化感潜力分蘖洋葱根系分泌物均增加了黄瓜根际土壤细菌和放线菌数量,降低了真菌和尖镰孢菌数量,化感潜力强的品种(L-06)效果更显著;不同化感潜力分蘖洋葱根系分泌物均能提高黄瓜根际土壤细菌群落丰富度,差异条带的序列片段经比对推测为3大细菌类群:Actinobacteria(放线菌纲)、Proteobacteria(变形菌纲)和Anaerolineaceae(厌氧绳菌纲),其中厌氧绳菌只出现在化感潜力强(L-06)的处理中.化感潜力强(L-06)、浓度高(10 mL·株-1)的分蘖洋葱根系分泌物更有利于黄瓜根际土壤细菌群落丰富度的提高.%Taking the Chinese onion cultivars with different allelopathy potentials as the donor and cucumber as the accepter, this paper studied the effects of Chinese onion' s root exudates on the seedlings growth of cucumber and the culturable microbial number and bacterial community structure in the seedlings rhizosphere soil. The root exudates of the Chinese onion cultivars could promote the growth of cucumber seedlings, and the stimulatory effect increased with the increasing concentration of the root exudates. However, at the same concentrations of root exudates, the stimulatory effect had no significant differences between the Chinese onion cultivars with strong and weak allelopathy potential. The root exudates of the Chinese onion cultivars increased the individual numbers of bacteria and actinomyces but decreased those of fungi and Fusarium in rhizosphere soil, being more significant for the Chinese onion cultivar with high allelopathy potential (L-06

  17. 铅胁迫下小花南芥与玉米间作对根系分泌物有机酸的影响%Effects of Arabisalpina L. var. parviflora Franch and Zea mays L. intercropping system on root-exudated organic acids under lead stress

    Institute of Scientific and Technical Information of China (English)

    王吉秀; 湛方栋; 李元; 祖艳群; 秦丽; 何永美; 李明锐

    2016-01-01

    为了揭示 Pb 胁迫对间作和单作的超累积植物和作物根系分泌低分子有机酸的影响,研究设置400 mg·L-1 Pb 胁迫,采用水培曝气法试验,以玉米和小花南芥单作为对照处理,研究 Pb 胁迫下玉米和小花南芥间作对植物根系形态、根系分泌有机酸及 Pb 吸收的影响。结果表明:与单作相比,间作小花南芥情况下,玉米根系分泌物检测到乳酸;玉米分根条数、根表面积和根密度与单作相比分别增加60%、15%和42%,地下部和地上部干重生物量分别增加108%和75%,玉米地下部 Pb 含量下降44%;与单作相比,间作玉米条件下,小花南芥根系分泌物检测到乙酸和乳酸,小花南芥根系分泌物量与单作相比增加103%~1700%,小花南芥地下部和地上部 Pb 累积量分别比单作增加49%和75%,转运系数增加22%。相关分析结果表明,单作小花南芥只有地上部Pb 累积量与草酸显著相关,而间作小花南芥地下部和地上部 Pb 累积量与草酸、柠檬酸和苹果酸显著相关。研究表明超富集植物小花南芥与玉米间作体系,根系分泌的有机酸改变了 Pb 在小花南芥和玉米体内的累积特征,促进超累积植物小花南芥累积 Pb,减少农作物玉米植株体内 Pb 含量。Pb 胁迫下超累积植物小花南芥与玉米间作是一种可行的修复模式。%Cultivated soils contamination by heavy metals have become increasingly contentious to decision makers, farmers, consumers and health professionals around the globe. Phytoremediation is a key strategy for decontaminating cultivated soils polluted by heavy metals. Hyperaccumulator plants are limited by their soil occupation rather than agricultural production in China. Intercropping system of hyperaccumulator plants and crops have been recommended for both of remediation and production in the same time. The accumulation of heavy metal in plants is due to root growth and root exudates. However, plant root

  18. Ryecyanatines A and B and ryecarbonitrilines A and B, substituted cyanatophenol, cyanatobenzo[1,3]dioxole, and benzo[1,3]dioxolecarbonitriles from rye (Secale cereale L.) root exudates: Novel metabolites with allelopathic activity on Orobanche seed germination and radicle growth.

    Science.gov (United States)

    Cimmino, Alessio; Fernández-Aparicio, Mónica; Avolio, Fabiana; Yoneyama, Koichi; Rubiales, Diego; Evidente, Antonio

    2015-01-01

    Orobanche and Phelipanche species (the broomrapes) are root parasitic plants, some of which represent serious weed problems causing heavy yield losses on important crops. Current control relies on the use of certain agronomic practices, resistant crop varieties, and herbicides, albeit success has been marginal. Agronomic practices such as the use of allelopathic species in intercropping or cover crops, or the use of direct seedling over residues of allelopathic species incorporate the principle of allelopathy exerted by molecules exuded from roots or released by crop residues to control broomrapes. In addition, the isolation of natural substances from root exudates of plants with potential to inhibit broomrape development opens the door to the design of new herbicides based on natural and benign sources. Ryecyanatines A and B and ryecarbonitrilines A and B, the first new substituted cyanatophenol, substituted cyanatobenzo[1,3]dioxole, and the latter two new substituted benzo[1,3]dioxolecarbonitriles were isolated from rye (Secale cereale L.) root exudates. They were characterized as 4-cyanato-2-methoxyphenol, 2-cyanato-benzo[1,3]dioxole, 2-methoxybenzo[1,3]dioxole-5-carbonitrile and benzo[1,3]dioxole-2-carbonitrile by spectroscopic (essentially NMR and HRESI MS spectra) methods. These compounds were investigated for allelopathic activity on Orobanche germination and development. Ryecarbonitriline A induced germination of Orobanche cumana seeds, and this germination can be considered as suicidal because O. cumana does not parasite rye roots and cannot survive without host resources beyond germination stage. In addition, ryecyanatine A promotes a rapid cessation of O. cumana, Orobanche crenata and Orobanche minor radicle growth with the promotion of a layer of papillae at the radicle tip in O. cumana and O. crenata hampering the contact of the parasite to the host. Ryecarbonitriline B also displayed the same activity although being less active than ryecyanatine A and

  19. 不同品系小麦根系分泌物对黄瓜化感作用的初步研究%Primary Studies about Root Exudates from Different Wheat Cultivars on Cucumber Allelopathy

    Institute of Scientific and Technical Information of China (English)

    马亚飞; 杨平; 吴凤芝

    2011-01-01

    以黑龙江省40个小麦品系为供体,以黄瓜品种津优1号为受体,采用培养皿滤纸生物测试法,初步研究了不同品系小麦根系分泌物对黄瓜幼苗的化感作用.结果表明:不同品系小麦根系分泌物对黄瓜种子发芽率、幼苗根长、胚轴长及幼苗鲜质量的影响存在差异.由综合效应(SE)可以看出,龙辐04-0348对黄瓜幼苗的化感促进作用最强,龙辐17化感抑制作用最强,综合化感效应分别为-15.37%和7.76%.%Taking 40 wheat cultivars in Heilongjiang Province as donor and 'Jinyou No.l' cucumber ( Cucumis sativus L. ) as accepter, allelopathy of root exudates from different wheat cultivars on cucumber seedlings were investigated in petri dish experiment. Results showed that different wheat cultivars had different allelopathy on cucumber germination rate, radicle length, radicle and shoot fresh weight. Judging from synthesize effect (SE) value, 'Longfu 04-0348' had the most significant stimulatory effect, and ‘Longfu 17' had the most significant inhibitory effect, their SE values were -15.37 % and 7.76 %,respectively.

  20. 线辣椒不同生育阶段根系分泌物的组分分析%Component Analysis of the Root Exudates at Different Growth Stages in Chili Pepper

    Institute of Scientific and Technical Information of China (English)

    谢振华; 赵尊练; 武国平; 叶新华; 史联联; 郭建伟

    2012-01-01

    Root exudates are one of the important factors causing continuous cropping obstacles. In order to resolve the problem of continuous cropping obstacles in chili pepper, the composition and content of the root exudates of chili pepper Shaanjiao 2006 with hydroponics in different growth stages were determined by means of GC-MS. The results showed that the chili pepper root exudates various organic compounds. The 21,27 and 31 kinds of organic compounds, of which similarity (or matching) in more than 70%, were determined in seedling 30 d, seedling 60 d and flowering plant 30 d respectively. Among these organic compounds, the relative content of 21, 24 and 29 kinds was more than 0. 20% respectively. The organic compounds from three growth stages can be divided into eight types, i.e. acids, phenols, hydrocarbons, esters, alcohols, amines, ketones, benzene and other heterocy-clic. The esters is the largest proportion and the total relative content in three growth stages is 67.29%, 56.07% and 59. 51%, respectively. There existed 13 kinds of substances in all of three growth stages. There is 3, 5 and 12 kind's unique material in the three growth stages respectively. In the organic compounds determined, 17 kinds have been proved by previous studies to have allelopathic effects. Among these 17 kinds, there are 9 kinds of substances in the 3 stages of growth. There are three kinds of substances in the two growth stages of flowering plant 30 d and seedling 30 d (or seedling 60 d). There are two kinds of unique material in the growth stages of seedling 60 d, and there are three kinds of unique material in the growth stages of flowering plant 30 d.%根系分泌物是引起连作障碍的原因之一.为解决线辣椒栽培中连作障碍问题,以陕西关中地区线辣椒主栽品种陕椒2006为试材,采用水培收集、气质联用仪(GC-MS)检测,分析陕椒2006在不同生长发育阶段根系分泌物的组成成分和相对含量.结果表明,线辣椒根系分泌物

  1. Oxidation deoxidize metabolism in the rice altered lateral root mutant RM109

    International Nuclear Information System (INIS)

    The author reports the characteristics of a 2,4-D resistance mutant, altered lateral root, RM109, which is deficient in SDH (succinate dehydrogenase) activity. The SDH activity of RM109 was 60%-70% of that the wild type. Oochikara, roots is treated with reducer NADPH, NADH and FAD, the SDH activity of RM109 were lower than Oochikara. Genetic analysis in the F1 and F2 indicated that SDH activity in the mutant was transmitted by a single dominant nuclear gene. The observations of resistance to plant hormone, TIBA and H2O2 showed that the resistance to 2,4-D, NAA, TIBA and H2O2 with RM109 were 12,8,6 and 0.24 times of those with Oochikara, respectively. These results indicated that the mutant was deficient in oxidation deoxidize metabolism

  2. Striga seed-germination activity of root exudates and compounds present in stems of Striga host and nonhost (trap crop) plants is reduced due to root colonization by arbuscular mycorrhizal fungi.

    NARCIS (Netherlands)

    Lendzemo, V.W.; Kuyper, T.W.; Vierheilig, H.

    2009-01-01

    Root colonization by arbuscular mycorrhizal (AM) fungi reduces stimulation of seed germination of the plant parasite Striga (Orobanchaceae). This reduction can affect not only host plants for Striga, resulting in a lower parasite incidence, but also false hosts or trap crops, which induce suicidal S

  3. Evaluation of the morphological alteration of the root surface radiated with a diode laser

    International Nuclear Information System (INIS)

    The diode laser has been studied for periodontal therapy, as much for removal of calculus as for microbial reduction of periodontal pockets, as well as the visible analgesic effects and biomodulation capacity. For this reason the purpose of this study was to evaluate the morphological alteration of the root surface after radiation with the diode laser, 808 nm through analysis by scanning electron microscopy (SEM). Besides this, to verify the temperature variations caused during the radiation, a thermometer put into the dentinal wall of the root canal was used. In all, 18 teeth were used, 15 of which for the SEM study, and the other 3 were used to temperature variation analysis. The 25 samples were scraped on the root surface and planed with manual instruments. The other 5 were not subjected to any type of treatment. This, 6 groups of 5 samples each were formed. Control Group C whose samples had not received any treatment; Control Group C 1 was only scraped and polished conventionally with Hu-Friedy Gracey curettes 5 and 6; the other samples groups L1, L2, L3, L4 were radiated by diode laser using parameters of power 1,0 W; 1,2 W; 1,4 W; and 1,6 W respectively, 2 times for 10 seconds with 20 seconds intervals between each radiation in continuous mode. The results with relation to the increase of temperature in the interior of the root canal demonstrated that there was an increase of more than 5 degree Celsius. The results of the scanning electron microscope analysis of Control Group C demonstrated great irregularity and ridges on the root surface, with the presence of a dentine layer. Control Group C1 presented a similar aspect to Group L 1's, smoother and more homogeneous surface. Groups L2, L3, and L4 presented scratches alternating with smoother areas showing that fiber contacted the surface of the sample. The results reconfirmed the necessity of further studies using diode laser, with a beam of light emitted in an interrupted mode to improve the control of the

  4. Bioavailability of zinc and phosphorus in calcareous soils as affected by citrate exudation

    NARCIS (Netherlands)

    Duffner, A.; Hoffland, E.; Temminghoff, E.J.M.

    2012-01-01

    Aims Zinc (Zn) and phosphorus (P) deficiency often occurs at the same time and limits crop production in many soils. It has been suggested that citrate root exudation is a response of plants to both deficiencies. We used white lupin (Lupinus albus L.) as a model plant to clarify if citrate exuded by

  5. Exudation of Allelopathic Substances in Buckwheat (Fagopyrum esculentum Moench)

    Czech Academy of Sciences Publication Activity Database

    Kalinová, J.; Vrchotová, Naděžda; Tříska, Jan

    2007-01-01

    Roč. 55, č. 16 (2007), s. 6453-6459. ISSN 0021-8561 Institutional research plan: CEZ:AV0Z60870520 Keywords : Allelopathy * Epicatechin * Fagopyrum esculentum * palmitic acid * root exudates Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.532, year: 2007

  6. Effects of Phosphorus Stress on the Root Morphology and Root Exudates in Different Sugar Beet Genotypes%磷胁迫对不同基因型甜菜根系形态及根分泌物的影响

    Institute of Scientific and Technical Information of China (English)

    周建朝; 王孝纯; 邓艳红; 林晓坤; 王艳

    2011-01-01

    Phosphorus deficiency was induced in sugar beet plants (Beta vulgaris L., ‘var. 14’, ‘var. 17’ and ‘var. 20’ with different resistance ability to phosphorus stress), cultured hydroponically and sandily under standardized environmental conditions, by removing phosphorus from the nutrient supply at the seedling stage.Root morphology, H + excretion and organic acid in rhizosphere were investigated. The main results were showed as following: the average length of roots and the ratio of root to shoot in all genotypes were increased significantly (P<0.05), among which, the decreasing range of ‘var. 14’ was the biggest one; sugar beet root mainly excreted oxalic, lactic, maleic acid and trans-butenedioic acid, among which, the first two kinds of the organic acids were the main ingredient, and the phenomena of the significant increase in the secretion amount of those two kinds acids was only appeared in ‘var. 20’ with higher resistance to phosphorus stress;phosphorus deficiency stimulated the environment changed in root vicinity of sugar beet, and showed as an increase of the H+ secretion in all the genotypes used in the experiment, but the increased amount of H+ were genetic dependent, i.e. ‘var.20’ >‘ var. 17’ > ‘ var. 14’.%选用了3种不同抗磷胁迫能力的基因型甜菜种质材料'品14'、'品17'和'品20',通过液培和沙培法对低磷胁迫下甜菜根长、根冠比、根系H+及有机酸分泌等形态和生理特性进行了研究.结果表明:(1)磷胁迫对甜菜根系的形态特征影响显著,与正常磷营养水平比,各基因型甜菜的根系长度和根冠比均有显著增加(P<0.05),其中抗磷胁迫能力最强的'品20'增加幅度显著高于其他2个基因型;(2)甜菜根系主要分泌草酸、乳酸、马来酸及反丁烯二酸,其中大部分为草酸和乳酸,在低磷胁迫下,只有抗磷胁迫能力最强的'品20'此两种酸的分泌达到显著增加水平;(3)不同基因型甜菜受

  7. Phosphate starvation of maize inhibits lateral root formation and alters gene expression in the lateral root primordium zone

    Directory of Open Access Journals (Sweden)

    Li Zhaoxia

    2012-06-01

    Full Text Available Abstract Background Phosphorus (P is an essential macronutrient for all living organisms. Maize (Zea mays is an important human food, animal feed and energy crop throughout the world, and enormous quantities of phosphate fertilizer are required for maize cultivation. Thus, it is important to improve the efficiency of the use of phosphate fertilizer for maize. Results In this study, we analyzed the maize root response to phosphate starvation and performed a transcriptomic analysis of the 1.0-1.5 cm lateral root primordium zone. In the growth of plants, the root-to-shoot ratio (R/L was reduced in both low-phosphate (LP and sufficient-phosphate (SP solutions, but the ratio (R/L exhibited by the plants in the LP solution was higher than that of the SP plants. The growth of primary roots was slightly promoted after 6 days of phosphate starvation, whereas the numbers of lateral roots and lateral root primordia were significantly reduced, and these differences were increased when associated with the stress caused by phosphate starvation. Among the results of a transcriptomic analysis of the maize lateral root primordium zone, there were two highlights: 1 auxin signaling participated in the response and the modification of root morphology under low-phosphate conditions, which may occur via local concentration changes due to the biosynthesis and transport of auxin, and LOB domain proteins may be an intermediary between auxin signaling and root morphology; and 2 the observed retardation of lateral root development was the result of co-regulation of DNA replication, transcription, protein synthesis and degradation and cell growth. Conclusions These results indicated that maize roots show a different growth pattern than Arabidopsis under low-phosphate conditions, as the latter species has been observed to halt primary root growth when the root tip comes into contact with low-phosphate media. Moreover, our findings enrich our understanding of plant

  8. Effects of root exudates on the growth and development of male and female Morus alba seedlings%桑树(Morus alba)幼苗根系分泌物对雌雄植株生长发育的影响

    Institute of Scientific and Technical Information of China (English)

    竺诗慧; 董廷发; 刘刚; 肖娟; 朱娟; 曾贞; 陈德甫; 胥晓

    2016-01-01

    以桑树(Morus alba)雌雄幼苗为实验材料,采用水培法种植植株,将同龄单培雌雄植株及混培雌雄植株的根系分泌物水溶液分别倒入不同处理组(对照组不作处理),研究了不同来源的根系分泌物对受体雌雄植株生长和分配的影响。结果显示:桑树单培雌雄植株的根系分泌物促进了异性受体植株的生长和干物质积累,导致受体雌株的株高、基径、叶面积和根、茎、叶生物量以及受体雄株的根、茎生物量显著增加,雌株的增加幅度大于雄株。与对照相比,雌/雄株的株高、基径、叶面积以及根、茎、叶生物量分别增加了107%/31%、164%/41%、94%/31%、349%/52%、216%/53%和86%/43%。除雌株根系生物量和根冠比增加外,混培雌雄植株的根系分泌物对受体雌雄植株大部分生长和生物量性状均无显著影响。这些结果表明,不同来源的根系分泌物对受体桑树雌雄植株生长发育的影响不同。这种由根系分泌物引起的差异可能是雌雄植株间相互作用的一种机制。%To investigate effects on the growth and biomass allocation of male and femaleMorus alba seedlings by its root exudates from different origins, the seedlings were exposed to liquid medium containning the root exudates from single-planted seedlings of opposite sex or companion-planted seedlings (a male and a female), and the group without treatment was the control. All the plants were of the same age. The results show that the growth and dry matter accumulation of male and female seedlings were promoted by the root exudates from the opposite sex. In treatment of the exudates from the opposite sex, height, base diameter, leaf area, and biomasses of roots, stems and leaves of females were signiifcantly increased, and biomasses of stems and roots of males were also significantly increased. Furthermore, the increasing amplitude of females was higher than that of males. Compared with the

  9. Chromosomal and Nuclear Alterations in Root Tip Cells of Allium Cepa L. Induced by Alprazolam

    Science.gov (United States)

    Nefic, Hilada; Musanovic, Jasmin; Metovic, Azra; Kurteshi, Kemajl

    2013-01-01

    ABSTRACT Introduction: Alprazolam is a triazolobenzodiazepine used in panic disorders and other anxiety states. Target organ of Alprazolam is CNS, causing depression of respiration and consciousness. Aim: This study aimed to estimate the genotoxic potential of Alprazolam using Allium cepa test. Methods: Allium cepa is one of the most suitable plants for detecting different types of xenobiotics. The test enables the assessment of different genetic endpoints making possible damage to the DNA of humans to be predicted. Results: Alprazolam induced chromosomal (anaphase bridges, breaks, lagging and stickiness, abnormal spiralisation, multipolarity and polyploidy) and cytological aberrations, especially nuclear alterations (nuclear buds, fragmented nucleus and apoptotic bodies, cells without nucleus, binucleated and micronucleated cells), morphological alterations in shape and size of cells, spindle disturbance and polar deviation in root tip meristem cells of Allium cepa at all tested concentrations. Alprazolam also caused significant inhibition of mitotic index in these cells. Conclusion: These changes in cells are indicators of genotoxic potential of Alprazolam suggesting a need for further in vitro studies on animal and human lymphocytes as well as in vivo studies. PMID:25568504

  10. Altered microRNA expression following sciatic nerve resection in dorsal root ganglia of rats

    Institute of Scientific and Technical Information of China (English)

    Bin Yu; Songlin Zhou; Tianmei Qian; Yongjun Wang; Fei Ding; Xiaosong Gu

    2011-01-01

    MicroRNAs (miRNAs) are a class of small,non-coding RNAs (~22 nucleotides) that negatively regulate gene expression post-transcriptionally,either through translational inhibition or degradation of target mRNAs.We uncovered a previously unknown alteration in the expression of miRNAs in the dorsal root ganglia (DRG) at 1,4,7,and 14 days after resection of the sciatic nerve in rats using microarray analysis.Thirty-two significantly upregulated and 18 downregulated miRNAs were identified in the DRG at four time points following sciatic nerve injury.The expression of four consecutively deregulated miRNAs,analyzed by real-time Taqman polymerase chain reaction,was in agreement with the microarray data (upregulated: miR-21,miR-221; downregulated:miR-500,miR-551b),The potential targets for these miRNAs,altered after sciatic nerve resection,are involved mainly in nervous system development,multi-cellular organismal development,and the regulation of cellular processes.This study demonstrated a different involvement of miRNAs in the DRG after resection of the sciatic nerve in a rat model,and it may also contribute in illustrating the molecular mechanisms responsible for nerve regeneration.

  11. Altered susceptibility to infection by Sinorhizobium meliloti and Nectria haematococca in alfalfa roots with altered cell cycle.

    Science.gov (United States)

    Woo, H-H; Hirsch, A M; Hawes, M C

    2004-07-01

    Most infections of plant roots are initiated in the region of elongation; the mechanism for this tissue-specific localization pattern is unknown. In alfalfa expressing PsUGT1 antisense mRNA under the control of the cauliflower mosaic virus (CaMV) 35S promoter, the cell cycle in roots is completed in 48 h instead of 24 h, and border cell number is decreased by more than 99%. These plants were found to exhibit increased root-tip infection by a fungal pathogen and reduced nodule formation by a bacterial symbiont. Thus, the frequency of infection in the region of elongation by Nectria haematocca was unaffected, but infection of the root tip was increased by more than 90%; early stages of Sinorhizobium meliloti infection and nodule morphology were normal, but the frequency of nodulation was fourfold lower than in wild-type roots. PMID:15042410

  12. Water dynamics in the rhizosphere - a new model of coupled water uptake and mucilage exudation

    Science.gov (United States)

    Kroener, Eva; Holz, Maire; Ahmed, Mutez; Zarebanadkouki, Mohsen; Bittelli, Marco; Carminati, Andrea

    2016-04-01

    The flow of water from soil to plant roots is affected by the narrow region of soil close to the roots, the so-called rhizosphere. The rhizosphere is influenced by mucilage, a polymeric gel exuded by roots that alters the hydraulic properties of the rhizosphere. Here we present a model that accounts for: (a) an increase in equilibrium water retention curve caused by the water holding capacity of mucilage, (b) a reduction of hydraulic conductivity at a given water content due to the higher viscosity of mucilage and (c) the swelling and shrinking dynamics by decoupling water content and water potential and introducing a non-equilibrium water retention curve. The model has been tested for mixtures of soil and mucilage and we applied it to simulate observations of previous experiments with real plants growing in soil that show evidences of altered hydraulic dynamics in the rhizosphere. Furthermore we present results about how the parameters of the model depend on soil texture and root age. Finally we couple our hydraulic model to a diffusion model of mucilage into the soil. Opposed to classical solute transport models here the water flow in the rhizosphere is affected by the concentration distribution of mucilage.

  13. Copper-induced alteration in sucrose partitioning and its relationship to the root growth of two Elsholtzia haichowensis Sun populations.

    Science.gov (United States)

    Li, Min-Jing; Xiong, Zhi-Ting; Liu, Hui; Kuo, Yi-Ming; Tong, Lei

    2016-10-01

    Hydroponic culture was used to comparatively investigate the copper (Cu)-induced alteration to sucrose metabolism and biomass allocation in two Elsholtzia haichowensis Sun populations with one from a Cu-contaminated site (CS) and the other from a non-contaminated site (NCS). Experimental results revealed that biomass allocation preferred roots over shoots in CS population, and shoots over roots in NCS population under Cu exposure. The difference in biomass allocation was correlated with the difference in sucrose partitioning between the two populations. Cu treatment (45 μM) significantly decreased leaf sucrose content and increased root sucrose content in CS population as a result of the increased activities of leaf sucrose synthesis enzymes (sucrose phosphate synthetase and sucrose synthase) and root sucrose cleavage enzyme (vacuolar invertase), which led to increased sucrose transport from leaves to roots. In contrast, higher Cu treatment increased sucrose content in leaves and decreased sucrose content in roots in NCS population as a result of the decreased activities of root sucrose cleavage enzymes (vacuolar and cell wall invertases) that led to less sucrose transport from leaves to roots. These results provide important insights into carbon resource partitioning and biomass allocation strategies in metallophytes and are beneficial for the implementation of phytoremediation techniques. PMID:27153457

  14. Multitrophic interaction in the rhizosphere of maize: root feeding of Western corn rootworm larvae alters the microbial community composition.

    Directory of Open Access Journals (Sweden)

    Flavia Dematheis

    Full Text Available BACKGROUND: Larvae of the Western Corn Rootworm (WCR feeding on maize roots cause heavy economical losses in the US and in Europe. New or adapted pest management strategies urgently require a better understanding of the multitrophic interaction in the rhizosphere. This study aimed to investigate the effect of WCR root feeding on the microbial communities colonizing the maize rhizosphere. METHODOLOGY/PRINCIPAL FINDINGS: In a greenhouse experiment, maize lines KWS13, KWS14, KWS15 and MON88017 were grown in three different soil types in presence and in absence of WCR larvae. Bacterial and fungal community structures were analyzed by denaturing gradient gel electrophoresis (DGGE of the 16S rRNA gene and ITS fragments, PCR amplified from the total rhizosphere community DNA. DGGE bands with increased intensity were excised from the gel, cloned and sequenced in order to identify specific bacteria responding to WCR larval feeding. DGGE fingerprints showed that the soil type and the maize line influenced the fungal and bacterial communities inhabiting the maize rhizosphere. WCR larval feeding affected the rhiyosphere microbial populations in a soil type and maize line dependent manner. DGGE band sequencing revealed an increased abundance of Acinetobacter calcoaceticus in the rhizosphere of several maize lines in all soil types upon WCR larval feeding. CONCLUSION/SIGNIFICANCE: The effects of both rhizosphere and WCR larval feeding seemed to be stronger on bacterial communities than on fungi. Bacterial and fungal community shifts in response to larval feeding were most likely due to changes of root exudation patterns. The increased abundance of A. calcoaceticus suggested that phenolic compounds were released upon WCR wounding.

  15. 棉花根系分泌物对土壤速效养分和酶活性及微生物数量的影响%Effects of Cotton Root Exudates on Available Soil Nutrition, Enzyme Activity and Microorganism Quantity

    Institute of Scientific and Technical Information of China (English)

    赵小亮; 刘新虎; 贺江舟; 万传星; 龚明福; 张利莉

    2009-01-01

    采用水培法收集棉花根系分泌物,在耕作1年的土壤中添加棉花根系分泌物,培养10 d后测定土壤中速效养分、酶活性及微生物数量.结果显示,(1)棉花根系分泌物能极显著提高土壤中速效K和速效P含量4.31%~15.03%和5.99%~24.31%(P<0.01);高浓度分泌物处理下速效N含量比对照显著提高11.39%(P<0.05),其它处理影响不显著;各浓度分泌物对土壤有机质含量均无显著影响.(2)各浓度棉花根系分泌物均使土壤中转化酶活性显著提高,且随分泌物浓度的增加而显著增强;低浓度分泌物能显著提高土壤中磷酸酶的活性,所有浓度处理对土壤脲酶活性均无显著影响.(3)中、高浓度的棉花根系分泌物能显著增加土壤中细菌的数量,低浓度的分泌物能显著增加土壤中真菌的数量,而不同浓度处理的土壤中放线菌的数量均无显著的变化.研究表明,棉花根系分泌物可通过促进土壤细菌及土壤真菌的繁殖来增强土壤转化酶和磷酸酶活性,提高土壤速效P、速效K及速效N含量,从而对棉花根际微环境产生深刻影响.%Cotton seedlings were cultured in hydroponics,root exudates were collected by concentrating the deionized water,in which the cotton seedlings transferring to.Collected root exudates were subjected to the soil with cotton cultivation for one year.Soil available nutrition contents,enzyme activities and microorganism quantity were determined after ten days incubation of treated soil.The results showed that the root exudates of cotton can significantly enhance the contents of the available K and available P in soil.In three treatments,soil available P significantly increased by 5.99%,13.14% and 24.31% (P<0.01)and available K significantly elevated by 4.31%,8.26% and 15.03% (P<0.01).Only higher input of cotton root exudates improved the content of the available N by 11.39% (P<0.05) in soil.And any influence was observed in soil organic matter in all

  16. Properties of Plasma Membrane from Pea Root Seedlings under Altered Gravity

    Science.gov (United States)

    Klymchuk, D.; Baranenko, V.; Vorobyova, T. V.; Kurylenko, I.; Chyzhykova, O.; Dubovoy, V.

    In this study, the properties of pea (Pisum sativum L.) plasma membrane were examined to determine how the membrane structure and functions are regulated in response to clinorotation (2 rev/min) conditions. Membrane preparations enriched by plasma membrane vesicles were obtained by aqueous two-phase partitioning from 6-day seedling roots. The specific characteristics of H^+-ATPase, lípid composition and peroxidation intensity as well as fluidity of lipid bilayer were analysed. ATP hydrolytic activity was inhibited by ortovanadate and was insensitive to aside and nitrate in sealed plasma membrane vesicles isolated from both clinorotated and control seedlings. Plasma membrane vesicles from clinorotated seedlings in comparison to controls were characterised by increase in the total lipid/protein ratio, ATP hydrolytic activity and intensifying of lipid peroxidation. Sitosterol and campesterol were the predominant free sterol species. Clinorotated seedlings contained a slightly higher level of unsaturated fatty acid than controls. Plasma membrane vesicles were labelled with pyrene and fluorescence originating from monomeric (I_M) molecules and excimeric (I_E) aggregates were measured. The calculated I_E/I_M values were higher in clinorotated seedlings compared with controls reflecting the reduction in membrane microviscosity. The involvement of the changes in plasma membrane lipid content and composition, fluidity and H^+-ATPase activity in response of pea seedlings to altered gravity is discussed.

  17. Phosphate availability alters architecture and causes changes in hormone sensitivity in the Arabidopsis root system.

    Science.gov (United States)

    López-Bucio, José; Hernández-Abreu, Esmeralda; Sánchez-Calderón, Lenin; Nieto-Jacobo, María Fernanda; Simpson, June; Herrera-Estrella, Luis

    2002-05-01

    The postembryonic developmental program of the plant root system is plastic and allows changes in root architecture to adapt to environmental conditions such as water and nutrient availability. Among essential nutrients, phosphorus (P) often limits plant productivity because of its low mobility in soil. Therefore, the architecture of the root system may determine the capacity of the plant to acquire this nutrient. We studied the effect of P availability on the development of the root system in Arabidopsis. We found that at P-limiting conditions (increase in auxin sensitivity in the roots of P-deprived Arabidopsis seedlings. It was also found that the axr1-3, axr2-1, and axr4-1 Arabidopsis mutants have normal responses to low P availability conditions, whereas the iaa28-1 mutant shows resistance to the stimulatory effects of low P on root hair and lateral root formation. Analysis of ethylene signaling mutants and treatments with 1-aminocyclopropane-1-carboxylic acid showed that ethylene does not promote lateral root formation under P deprivation. These results suggest that in Arabidopsis, auxin sensitivity may play a fundamental role in the modifications of root architecture by P availability. PMID:12011355

  18. Microcystin-LR induces abnormal root development by altering microtubule organization in tissue-cultured common reed (Phragmites australis) plantlets.

    Science.gov (United States)

    Máthé, Csaba; Beyer, Dániel; Erdodi, Ferenc; Serfozo, Zoltán; Székvölgyi, Lóránt; Vasas, Gábor; M-Hamvas, Márta; Jámbrik, Katalin; Gonda, Sándor; Kiss, Andrea; Szigeti, Zsuzsa M; Surányi, Gyula

    2009-05-01

    Microcystin-LR (MC-LR) is a heptapeptide cyanotoxin, known to be a potent inhibitor of type 1 and 2A protein phosphatases in eukaryotes. Our aim was to investigate the effect of MC-LR on the organization of microtubules and mitotic chromatin in relation to its possible effects on cell and whole organ morphology in roots of common reed (Phragmites australis). P. australis is a widespread freshwater and brackish water aquatic macrophyte, frequently exposed to phytotoxins in eutrophic waters. Reed plantlets regenerated from embryogenic calli were treated with 0.001-40 microg ml(-1) (0.001-40.2 microM) MC-LR for 2-20 days. At 0.5 microg ml(-1) MC-LR and at higher cyanotoxin concentrations, the inhibition of protein phosphatase activity by MC-LR induced alterations in reed root growth and morphology, including abnormal lateral root development and the radial swelling of cells in the elongation zone of primary and lateral roots. Both short-term (2-5 days) and long-term (10-20 days) of cyanotoxin treatment induced microtubule disruption in meristems and in the elongation and differentiation zones. Microtubule disruption was accompanied by root cell shape alteration. At concentrations of 0.5-5 microg ml(-1), MC-LR increased mitotic index at long-term exposure and induced the increase of the percentage of meristematic cells in prophase as well as telophase and cytokinesis of late mitosis. High cyanotoxin concentrations (10-40 microg ml(-1)) inhibited mitosis at as short as 2 days of exposure. The alteration of microtubule organization was observed in mitotic cells at all exposure periods studied, at cyanotoxin concentrations of 0.5-40 microg ml(-1). MC-LR induced spindle anomalies at the metaphase-anaphase transition, the formation of asymmetric anaphase spindles and abnormal sister chromatid separation. This paper reports for the first time that MC-LR induces cytoskeletal changes that lead to alterations of root architecture and development in common reed and generally, in

  19. Efeito de exsudatos radiculares em endósporos de Pasteuria penetrans e em juvenis do segundo estádio de Meloidogyne incognita Effect of root exudates on endospores of Pasteuria penetrans and on second-stage juvenile of Meloidogyne incognita

    Directory of Open Access Journals (Sweden)

    Fernando da Silva Rocha

    2004-12-01

    Full Text Available Juvenis do segundo estádio (J2 de Meloidogyne incognita foram incubados nos exsudatos radiculares de soja (Glycine max, tomateiro (Lycopersicon esculentum, cafeeiro (Coffea arabica, feijoeiro (Phaseolus vulgaris, mostarda (Brassica rapa, Crotalaria juncea e C. spectabilis e em água por 12 h. Em seguida, realizou-se o teste de adesão por centrifugação ou por borbulhamento. Em outro ensaio, endósporos de Pasteuria penetrans foram incubados por quatro dias a 26 ºC nos exsudatos e submetidos à adesão em J2 de M. incognita, sob borbulhamento constante por 24 h em tubos contendo água. Os J2 com endósporos aderidos pelo teste de borbulhamento foram inoculados em mudas de tomateiro. Verificou-se que a incubação dos J2 por 12 h nos exsudatos radiculares testados reduziu o número de endósporos de P. penetrans por J2 independentemente do método de adesão empregado. Os J2 incubados nos exsudatos radiculares testados proporcionaram menor número de fêmeas parasitadas em tomateiro em relação à testemunha (água, bem como menor número de galhas com exceção dos J2 incubados em exsudato do próprio tomateiro. A reprodução dos J2 incubados nos exsudatos radiculares não foi afetada quando comparada à testemunha. A incubação dos endósporos nos exsudatos das plantas testadas reduziu a adesão e a infetividade em J2, em relação à testemunha. Após 28 dias da inoculação, observou-se redução no número de fêmeas parasitadas resultantes da infecção desses J2 com endósporos incubados em exsudatos radiculares comparada com aqueles incubados em água. O parasitismo do J2 com endósporos tratados com exsudatos radiculares e a reprodutividade de fêmeas oriundas da infetividade desses J2 foram semelhantes aos incubados em água.In one assay, second stage juveniles (J2 of Meloidogyne incognita were incubated in root exudates of soybean (Glycine max, tomato (Lycopersicon esculentum, coffee (Coffea arabica, bean (Phaseolus vulgaris

  20. KATP channel subunits in rat dorsal root ganglia: alterations by painful axotomy

    Directory of Open Access Journals (Sweden)

    Gemes Geza

    2010-01-01

    Full Text Available Abstract Background ATP-sensitive potassium (KATP channels in neurons mediate neuroprotection, they regulate membrane excitability, and they control neurotransmitter release. Because loss of DRG neuronal KATP currents is involved in the pathophysiology of pain after peripheral nerve injury, we characterized the distribution of the KATP channel subunits in rat DRG, and determined their alterations by painful axotomy using RT-PCR, immunohistochemistry and electron microscopy. Results PCR demonstrated Kir6.1, Kir6.2, SUR1 and SUR2 transcripts in control DRG neurons. Protein expression for all but Kir6.1 was confirmed by Western blots and immunohistochemistry. Immunostaining of these subunits was identified by fluorescent and confocal microscopy in plasmalemmal and nuclear membranes, in the cytosol, along the peripheral fibers, and in satellite glial cells. Kir6.2 co-localized with SUR1 subunits. Kir6.2, SUR1, and SUR2 subunits were identified in neuronal subpopulations, categorized by positive or negative NF200 or CGRP staining. KATP current recorded in excised patches was blocked by glybenclamide, but preincubation with antibody against SUR1 abolished this blocking effect of glybenclamide, confirming that the antibody targets the SUR1 protein in the neuronal plasmalemmal membrane. In the myelinated nerve fibers we observed anti-SUR1 immunostaining in regularly spaced funneled-shaped structures. These structures were identified by electron microscopy as Schmidt-Lanterman incisures (SLI formed by the Schwann cells. Immunostaining against SUR1 and Kir6.2 colocalized with anti-Caspr at paranodal sites. DRG excised from rats made hyperalgesic by spinal nerve ligation exhibited similar staining against Kir6.2, SUR1 or SUR2 as DRG from controls, but showed decreased prevalence of SUR1 immunofluorescent NF200 positive neurons. In DRG and dorsal roots proximal to axotomy SLI were smaller and showed decreased SUR1 immunofluorescence. Conclusions We

  1. Aqueous root extract ofLecaniodiscus cupanioides restores the alterations in testicular parameters of sexually impaired male rats

    Institute of Scientific and Technical Information of China (English)

    Quadri O Nurudeen; Taofeek O Ajiboye

    2012-01-01

    Objective:This study aimed to investigate the effects of aqueous root extract ofLecaniodiscus cupanioides (L.cupanioides)on the alterations in the testicular parameters of paroxetine-treated rats.Methods:Group A rats which is the control received distilled water orally for 5 d. Groups B, C, D, E and F consisted of paroxetine-induced sexual dysfunction rats. In addition, Groups C, D, E and F rats were orally treated with 25, 50 and 100 mg/kg body weight of the extract and 7.14 mg/kg body weight of PowMax once daily for 5 d respectively.Results:Paroxetine-induced sexual dysfunction resulted into significant (P<0.05) reduction in the levels of testicular protein, sialic acid, glycogen and cholesterols. These decrease were dose dependently reversed by aqueous root extract ofL. cupanioides. The decrease in the specific activities of acid and alkaline phosphatases, lactate dehydrogenase and gamma-glutamyl transferase in the testes of paroxetine-treated rats were significantly (P<0.05) reversed. Testicular testosterone level decreased significantly (P<0.05) in sexually impaired rats. This decrease was significantly prevented by aqueous root extract ofL. cupanioides. All these alterations brought about by the administration of the extract (25 and 50 mg/kg body weight) compared significantly (P<0.05) with the reference drug, while the 100 mg/kg body weight of the extract compared significantly (P<0.05) with the control.Conclusions:The results of this study showed that aqueous root extract ofL. cupanioidesrestored the alterations in the testicular function parameters of sexually impaired rats. Thus supporting the use of the plants in the management of sexual dysfunction in the folkloric medicine of Nigeria.

  2. Chromate alters root system architecture and activates expression of genes involved in iron homeostasis and signaling in Arabidopsis thaliana.

    Science.gov (United States)

    Martínez-Trujillo, Miguel; Méndez-Bravo, Alfonso; Ortiz-Castro, Randy; Hernández-Madrigal, Fátima; Ibarra-Laclette, Enrique; Ruiz-Herrera, León Francisco; Long, Terri A; Cervantes, Carlos; Herrera-Estrella, Luis; López-Bucio, José

    2014-09-01

    Soil contamination by hexavalent chromium [Cr(VI) or chromate] due to anthropogenic activities has become an increasingly important environmental problem. To date few studies have been performed to elucidate the signaling networks involved on adaptive responses to (CrVI) toxicity in plants. In this work, we report that depending upon its concentration, Cr(VI) alters in different ways the architecture of the root system in Arabidopsis thaliana seedlings. Low concentrations of Cr (20-40 µM) promoted primary root growth, while concentrations higher than 60 µM Cr repressed growth and increased formation of root hairs, lateral root primordia and adventitious roots. We analyzed global gene expression changes in seedlings grown in media supplied with 20 or 140 µM Cr. The level of 731 transcripts was significantly modified in response to Cr treatment with only five genes common to both Cr concentrations. Interestingly, 23 genes related to iron (Fe) acquisition were up-regulated including IRT1, YSL2, FRO5, BHLH100, BHLH101 and BHLH039 and the master controllers of Fe deficiency responses PYE and BTS were specifically activated in pericycle cells. It was also found that increasing concentration of Cr in the plant correlated with a decrease in Fe content, but increased both acidification of the rhizosphere and activity of the ferric chelate reductase. Supply of Fe to Cr-treated Arabidopsis allowed primary root to resume growth and alleviated toxicity symptoms, indicating that Fe nutrition is a major target of Cr stress in plants. Our results show that low Cr levels are beneficial to plants and that toxic Cr concentrations activate a low-Fe rescue system. PMID:24928490

  3. Roots at the percolation threshold

    Science.gov (United States)

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

    2015-04-01

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

  4. Moth outbreaks alter root-associated fungal communities in subarctic mountain birch forests.

    Science.gov (United States)

    Saravesi, Karita; Aikio, Sami; Wäli, Piippa R; Ruotsalainen, Anna Liisa; Kaukonen, Maarit; Huusko, Karoliina; Suokas, Marko; Brown, Shawn P; Jumpponen, Ari; Tuomi, Juha; Markkola, Annamari

    2015-05-01

    Climate change has important implications on the abundance and range of insect pests in forest ecosystems. We studied responses of root-associated fungal communities to defoliation of mountain birch hosts by a massive geometrid moth outbreak through 454 pyrosequencing of tagged amplicons of the ITS2 rDNA region. We compared fungal diversity and community composition at three levels of moth defoliation (intact control, full defoliation in one season, full defoliation in two or more seasons), replicated in three localities. Defoliation caused dramatic shifts in functional and taxonomic community composition of root-associated fungi. Differentially defoliated mountain birch roots harbored distinct fungal communities, which correlated with increasing soil nutrients and decreasing amount of host trees with green foliar mass. Ectomycorrhizal fungi (EMF) abundance and richness declined by 70-80 % with increasing defoliation intensity, while saprotrophic and endophytic fungi seemed to benefit from defoliation. Moth herbivory also reduced dominance of Basidiomycota in the roots due to loss of basidiomycete EMF and increases in functionally unknown Ascomycota. Our results demonstrate the top-down control of belowground fungal communities by aboveground herbivory and suggest a marked reduction in the carbon flow from plants to soil fungi following defoliation. These results are among the first to provide evidence on cascading effects of natural herbivory on tree root-associated fungi at an ecosystem scale. PMID:25687127

  5. Cadmium-induced functional and ultrastructural alterations in roots of two transgenic cotton cultivars

    International Nuclear Information System (INIS)

    The toxic effect of cadmium (Cd) at increasing concentrations was studied with special attention being given to the root morphological and ultrastructural changes in two transgenic cotton cultivars viz. BR001 and GK30 and their wild relative viz. Coker 312. In comparison to their respective controls, low concentration (10 and 100 μM) of Cd greatly stimulated seed germination, while it was inhibited by highest concentration of Cd (1000 μM) in case of two transgenic cultivars. However, in Coker 312 the seed germination percentage progressively decreased over the control at all Cd levels. Various physiological and morphological parameters of the root and whole plant in both transgenic cotton cultivars and their relative wild cotton genotype respond differently towards the Cd toxicity. Bioavailability of Cd was concentration-dependent where seedling root captured more Cd as compared to shoot. BR001 accumulated more Cd followed by GK30, while Coker 312 was less Cd accumulator. The ultrastructural modifications in the root tip cells of both the transgenic cotton cultivars and their wild relative were also dose-dependent. With the increase in Cd levels, the fine structures of their root cells also invariably changed. Increase in plasmolysis of the plasma membrane, greater number of nucleoli and vacuoles and enlarged vacuoles could be observed in both transgenic cotton cultivars. In comparison to them, Coker 312 showed relatively well developed ultrastructures of the root tips except enlarged vacuoles and greater number of mitochondria. Moreover, the accumulation of Cd in the form of electron dense granules and crystals both in vacuoles and attached to cell walls were visible in both transgenic cotton cultivars and their wild relative. These results suggest that both transgenic cotton cultivars and their wild relative cotton genotype responded positively towards Cd stress at seedling stage, the internal Cd-detoxification might be through apoplastic and symplastic binding

  6. Cadmium-induced functional and ultrastructural alterations in roots of two transgenic cotton cultivars

    Energy Technology Data Exchange (ETDEWEB)

    Daud, M.K.; Sun, Yuqiang; Dawood, M. [Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China); Hayat, Y. [Institute of Bioinformatics, Zhejiang University, Hangzhou 310029 (China); Variath, M.T.; Wu Yuxiang [Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China); Raziuddin [Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China); Plant Breeding and Genetics Department, NWFP Agricultural University Peshawar, Peshawar (Pakistan); Mishkat, Ullah [Zoological Sciences Division, Pakistan Museum of Natural History, Garden Avenue, Shakarparian, Islamabad 44000 (Pakistan); Salahuddin [District Agriculture Extension Offices, Bannu Road, Dera Ismail Khan (NWFP) (Pakistan); Najeeb, Ullah [Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China); Zhu, Shuijin [Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China)], E-mail: shjzhu@zju.edu.cn

    2009-01-15

    The toxic effect of cadmium (Cd) at increasing concentrations was studied with special attention being given to the root morphological and ultrastructural changes in two transgenic cotton cultivars viz. BR001 and GK30 and their wild relative viz. Coker 312. In comparison to their respective controls, low concentration (10 and 100 {mu}M) of Cd greatly stimulated seed germination, while it was inhibited by highest concentration of Cd (1000 {mu}M) in case of two transgenic cultivars. However, in Coker 312 the seed germination percentage progressively decreased over the control at all Cd levels. Various physiological and morphological parameters of the root and whole plant in both transgenic cotton cultivars and their relative wild cotton genotype respond differently towards the Cd toxicity. Bioavailability of Cd was concentration-dependent where seedling root captured more Cd as compared to shoot. BR001 accumulated more Cd followed by GK30, while Coker 312 was less Cd accumulator. The ultrastructural modifications in the root tip cells of both the transgenic cotton cultivars and their wild relative were also dose-dependent. With the increase in Cd levels, the fine structures of their root cells also invariably changed. Increase in plasmolysis of the plasma membrane, greater number of nucleoli and vacuoles and enlarged vacuoles could be observed in both transgenic cotton cultivars. In comparison to them, Coker 312 showed relatively well developed ultrastructures of the root tips except enlarged vacuoles and greater number of mitochondria. Moreover, the accumulation of Cd in the form of electron dense granules and crystals both in vacuoles and attached to cell walls were visible in both transgenic cotton cultivars and their wild relative. These results suggest that both transgenic cotton cultivars and their wild relative cotton genotype responded positively towards Cd stress at seedling stage, the internal Cd-detoxification might be through apoplastic and symplastic

  7. Bioavailability of zinc and phosphorus in calcareous soils as affected by citrate exudation

    OpenAIRE

    Duffner, A.; Hoffland, E.; Temminghoff, E.J.M.

    2012-01-01

    Aims Zinc (Zn) and phosphorus (P) deficiency often occurs at the same time and limits crop production in many soils. It has been suggested that citrate root exudation is a response of plants to both deficiencies. We used white lupin (Lupinus albus L.) as a model plant to clarify if citrate exuded by roots could increase the bioavailability of Zn and P in calcareous soils. Methods White lupin was grown in nutrient solution and in two calcareous soils in a rhizobox. Rhizosphere soil solution wa...

  8. Tannins Alter Soil Organic Matter Extraction, Solubility of Metals, and Root Physiology

    Science.gov (United States)

    Tannins are common plant-derived polyphenolic compounds that precipitate proteins and react with other biomolecules but knowledge of their effects on soil organic matter, the solubility of metals, and root physiology is incomplete. Soil from forest and pasture systems was treated with tannic acid (...

  9. Plants may alter competition by modifying nutrient bioavailability in rhizosphere: a modeling approach

    OpenAIRE

    Raynaud, Xavier; Jaillard, Benoit; Leadley, Paul

    2008-01-01

    Plants modify nutrient availability by releasing chemicals in rhizosphere. This change in availability induced by roots (bioavailability) is known to improve nutrient uptake by individual plants releasing such compounds. Can this bioavailability alter plant competition for nutrients and under what conditions? To address these questions, we have developed a model of nutrient competition between plant species based on mechanistic descriptions of nutrient diffusion, plant exudation and plant upt...

  10. The Arabidopsis thaliana CLAVATA3/EMBRYO-SURROUNDING REGION 26 (CLE26) peptide is able to alter root architecture of Solanum lycopersicum and Brassica napus.

    Science.gov (United States)

    Czyzewicz, Nathan; De Smet, Ive

    2016-01-01

    Optimal development of root architecture is vital to the structure and nutrient absorption capabilities of any plant. We recently demonstrated that AtCLE26 regulates A. thaliana root architecture development, possibly by altering auxin distribution to the root apical meristem via inhibition of protophloem development. In addition, we showed that AtCLE26 application is able to induce a root architectural change in the monocots Brachypodium distachyon and Triticum aestivum. Here, we showed that application of the synthetic AtCLE26 peptide similarly affects other important agricultural species, such as Brassica napus and Solanum lycopersicum. PMID:26669515

  11. Cadmium-induced Functional and Ultrastructural Alterations in Roots of Two Transgenic Cotton Cultivars

    Institute of Scientific and Technical Information of China (English)

    DAUD M K; SUN Yu-qiang; ZHU Shui-jin

    2008-01-01

    @@ The toxic effect of cadmium (Cd) at increasing concentrations has been studied with special attention being given to root morphological and ultrastructural changes in two transgenic cotton cultivars viz.BR001 and GK30 and their wild relative cotton genotype viz.Coker 312.In comparison to their respective controls,low concentration (10 and 100 M) of Cd greatly stimulated seed germination,while it was inhibited by highest concentration of Cd (1000 M) in case of two transgenic cultivars.

  12. Cerebroside C increases tolerance to chilling injury and alters lipid composition in wheat roots.

    Directory of Open Access Journals (Sweden)

    Hong-Xia Li

    Full Text Available Chilling tolerance was increased in seed germination and root growth of wheat seedlings grown in media containing 20 µg/mL cerebroside C (CC, isolated from the endophytic Phyllosticta sp. TG78. Seeds treated with 20 µg/mL CC at 4 °C expressed the higher germination rate (77.78%, potential (23.46%, index (3.44 and the shorter germination time (6.19 d; root growth was also significantly improved by 13.76% in length, 13.44% in fresh weight and 6.88% in dry mass compared to controls. During the cultivation process at 4 °C for three days and the followed 24 h at 25 °C, lipid peroxidation, expressed by malondialdehyde (MDA content and relative membrane permeability (RMP was significantly reduced in CC-treated roots; activities of lipoxygenase (LOX, phospholipid C (PLC and phospholipid D (PLD were inhibited by 13.62-62.26%, 13.54-63.93% and 13.90-61.17%, respectively; unsaturation degree of fatty acids was enhanced through detecting the contents of CC-induced linoleic acid, linolenic acid, palmitic acid and stearic acid using GC-MS; capacities of superoxide dismutase (SOD, catalase (CAT and glutathione peroxidase (GSH-Px were individually increased by 7.69-46.06%, 3.37-37.96%, and -7.00-178.07%. These results suggest that increased chilling tolerance may be due, in part, to the reduction of lipid peroxidation and alternation of lipid composition of roots in the presence of CC.

  13. Alterations of physiology and gene expression due to long-term magnesium-deficiency differ between leaves and roots of Citrus reticulata.

    Science.gov (United States)

    Jin, Xiao-Lin; Ma, Cui-Lan; Yang, Lin-Tong; Chen, Li-Song

    2016-07-01

    Seedlings of Ponkan (Citrus reticulata) were irrigated with nutrient solution containing 0 (Mg-deficiency) or 1mM MgSO4 (control) every two day for 16 weeks. Thereafter, we examined magnesium (Mg)-deficiency-induced changes in leaf and root gas exchange, total soluble proteins and gene expression. Mg-deficiency lowered leaf CO2 assimilation, and increased leaf dark respiration. However, Mg-deficient roots had lower respiration. Total soluble protein level was not significantly altered by Mg-deficiency in roots, but was lower in Mg-deficient leaves than in controls. Using cDNA-AFLP, we obtained 70 and 71 differentially expressed genes from leaves and roots. These genes mainly functioned in signal transduction, stress response, carbohydrate and energy metabolism, cell transport, cell wall and cytoskeleton metabolism, nucleic acid, and protein metabolisms. Lipid metabolism (Ca(2+) signals)-related Mg-deficiency-responsive genes were isolated only from roots (leaves). Although little difference existed in the number of Mg-deficiency-responsive genes between them both, most of these genes only presented in Mg-deficient leaves or roots, and only four genes were shared by them both. Our data clearly demonstrated that Mg-deficiency-induced alterations of physiology and gene expression greatly differed between leaves and roots. In addition, we focused our discussion on the causes for photosynthetic decline in Mg-deficient leaves and the responses of roots to Mg-deficiency. PMID:27163764

  14. Malate Exudation by Six Aerobic Rice Genotypes Varying in Zinc Uptake Efficiency

    NARCIS (Netherlands)

    Gao, X.; Zhang, F.; Hoffland, E.

    2009-01-01

    Received for publication February 2, 2009. Zinc (Zn) uptake by plant roots from soils low in plant-available Zn may be increased by Zn-mobilizing rhizosphere processes, including exudation of low-molecular-weight organic anions. A rhizotron experiment with a low Zn clay soil and a nutrient solution

  15. Micropropagation and Phenolic exudation protocol for Excoecaria agallocha-an important mangrove

    Institute of Scientific and Technical Information of China (English)

    Manickam Arumugam; Rajaram Panneerselvam

    2012-01-01

    Objective: To develop a standard micropropagation protocol for an important vulnerable mangrove Excoecaria agallocha. Methods: Collection of explants, surface sterilization, phenolic exudation and medium was standardized. Shoot induction, shoot multiplication and rooting were carried out in MMS medium supplemented with BAP, Kinetin, Zeatin, 2ip, NAA, IAA and IBA. Hardening was carried out after root well established. Results: The best phenolic exudation removal was resulted in 4 g/L activated charcoal. The maximum shoot induction response showed in MMS medium and better shoot induction was performed in the concentration of BAP (3.9 μmol) and NAA (1.34 μmol). Rooting induction was performed high range at 5.02 μmol of IAA. Well rooted micro-shoots were hardened and acclimatized. Conclusions: From the present investigation, it can be concluded that a standard micropropagation protocol was developed for an important vulnerable mangrove species.

  16. Segregation and Alteration of Phenolic and Aliphatic Components of Root and Leaf Litter by Detritivores and Microbes

    Science.gov (United States)

    Filley, T. R.; Altmann, J.; Szlavecz, K. A.; Kalbitz, K.; Gamblin, D.; Nierop, K.

    2012-12-01

    The physical and microbial transformation of plant detritus in the litter layer and soil is accompanied by chemical separation of progressively soluble fractions and their movement into the rhizosphere driving subsequent soil processes. We investigated the combined action of specific detritivores, microbial decay, and leaching on the chemical separation of plant aromatic and aliphatic components from root, wood, and leaf tissue using 13C-TMAH thermochemolysis. This method enabled the simultaneous analysis of hydrolyzable tannin and lignin fragments, substituted fatty acids, and condensed tannin composition and revealed process-specific chemical transformations to plant secondary compounds. Long-term incubation and field sampling demonstrated how plant residues are progressively leached of the water soluble, oxidized fragments generated through decay. The residues appeared only slightly altered, in the case of brown rot wood, or enriched in aliphatic fragments, in the case of leaf and root tissue. Water extractable fractions were always selectively dominated by polyphenolics, either as demethylated lignin or tannins, and nearly devoid of aliphatic materials, despite high concentrations in the starting materials. Additionally, for plant materials with high tannin contents, such as pine needles, consumption and passage through some arthropod guts revealed what appeared to be microbially-mediated methylation of phenols, and a loss of tannins in leachates. These findings are indications for an in-situ phenol detoxification mechanism. This research provides important information regarding the links between biochemical decay and the chemical nature of organic matter removed and remaining in the soil profile.

  17. Altered neuronatin expression in the rat dorsal root ganglion after sciatic nerve transection

    Directory of Open Access Journals (Sweden)

    Wu Chih-Hsien

    2010-05-01

    Full Text Available Abstract Background Several molecular changes occur following axotomy, such as gene up-regulation and down-regulation. In our previous study using Affymetrix arrays, it was found that after the axotomy of sciatic nerve, there were many novel genes with significant expression changes. Among them, neuronatin (Nnat was the one which expression was significantly up-regulated. Nnat was identified as a gene selectively expressed in neonatal brains and markedly reduced in adult brains. The present study investigated whether the expression of Nnat correlates with symptoms of neuropathic pain in adult rats with transected sciatic nerve. Methods Western blotting, immunohistochemistry, and the Randall and Selitto test were used to study the protein content, and subcellular localization of Nnat in correlation with pain-related animal behavior. Results It was found that after nerve injury, the expression of Nnat was increased in total protein extracts. Unmyelinated C-fiber and thinly myelinated A-δ fiber in adult dorsal root ganglions (DRGs were the principal sub-population of primary afferent neurons with distributed Nnat. The increased expression of Nnat and its subcellular localization were related to mechanical hyperalgesia. Conclusions The results indicated that there was significant correlation between mechanical hyperalgesia in axotomy of sciatic nerve and the increased expression of Nnat in C-fiber and A-δ fiber of adult DRG neurons.

  18. Ring Nematodes (Mesocriconema xenoplax) Alter Root Colonization and Function of Arbuscular Mycorrhizal Fungi in Grape Roots in a Low P Soil

    Science.gov (United States)

    A reduction of arbuscules in roots of grapevines (Vitis vinifera) observed when ring nematodes were added to field microplots led to the hypothesis that nematode feeding suppresses arbuscules by competing for root carbohydrates. This hypothesis was tested by growing ‘Pinot noir’ grapevines in a fact...

  19. Alteration of P2X3 expression in dorsal root ganglia after sciatic nerve ligation

    Institute of Scientific and Technical Information of China (English)

    Guoxing Zhou; Lesi Xie; Qiben Wang; Qingping Yu; Xiaofu Liu; Qiumei Liu; Wei Peng; Zhicheng Zeng

    2007-01-01

    BACKGROUND: The expressions of P2X3 receptor in dorsal root ganglia (DRG) after different peripheral nerve injuries are diverse. It indicates the different roles of P2X3 in different models-caused neuropathologic pains.OBJECTIVE: To observe the expressions of P2X3 in corresponding DRG after sciatic nerve ligation in rats.DESIGN: Controlled observation experiment.SETTING: Department of Morphology, Hunan Traditional Chinese Medical College; Department of Human Anatomy and Neurobiology, Xiangya Medical College, Central South University.MATERIALS: Thirty-five healthy adult SD rats of clean grade an d either gender, weighing (200±20) g,were involved. According to the random digits table, the involved rats were randomized into 3 groups:normal group (n =5), sham-operated group (n =5) and experimental group (n =25). The experimental group were subdivided into 3, 7, 14, 21, 28 days groups according to different surviving time after operation, 5 rats at each time point. Polyclonal rabbit anti-P2X3 antibody (ABCAM company); biotinylated goat anti-rabbit IgG (Zhongshanjingqiao Biotechnical Co., Ltd., Beijing); Motic fluorescence microscope (Motic, Germany).METHODS: The experiments were carried out in the Department of Human Anatomy and Neurobiology,Xiangya Medical College, Central South University from June to December 2006. ① Rats of experimental group were created into models by ligation of right sciatic nerve according to the method of Seltzer et al. Left sciatic nerve was used as self-control. As for rats in the sham-operated group, ligation of sciatic nerve was omitted, but other procedures were the same as those in the experimental group. Rats of normal group were untouched. ② Rats of the normal group and sham-operated group survived for 14 days separately, and those of experimental group survived for corresponding time. After being deeply anesthetized by intraperitoneal injection of over-dose sodium pentobarbital, the rats of experimental group were transcardially

  20. Subretinal lipid exudation associated with untreated choroidal melanoma

    Directory of Open Access Journals (Sweden)

    C K Minija

    2011-01-01

    Full Text Available Subretinal lipid exudation in an untreated choroidal melanoma is very rare. It is seen following plaque radiotherapy in choroidal melanoma. There is only one case report of untreated choroidal melanoma with massive lipid exudation in a patient with metastatic hypernephroma. We report here a rare case of untreated choroidal melanoma with lipid exudation. Subretinal exudation that is rarely seen following plaque brachytherapy was noted at the borders of this untreated tumor. Lipid exudation partially resolved following brachytherapy.

  1. Methylobacterium-plant interaction genes regulated by plant exudate and quorum sensing molecules

    Directory of Open Access Journals (Sweden)

    Manuella Nóbrega Dourado

    2013-12-01

    Full Text Available Bacteria from the genus Methylobacterium interact symbiotically (endophytically and epiphytically with different plant species. These interactions can promote plant growth or induce systemic resistance, increasing plant fitness. The plant colonization is guided by molecular communication between bacteria-bacteria and bacteria-plants, where the bacteria recognize specific exuded compounds by other bacteria (e.g. homoserine molecules and/or by the plant roots (e.g. flavonoids, ethanol and methanol, respectively. In this context, the aim of this study was to evaluate the effect of quorum sensing molecules (N-acyl-homoserine lactones and plant exudates (including ethanol in the expression of a series of bacterial genes involved in Methylobacterium-plant interaction. The selected genes are related to bacterial metabolism (mxaF, adaptation to stressful environment (crtI, phoU and sss, to interactions with plant metabolism compounds (acdS and pathogenicity (patatin and phoU. Under in vitro conditions, our results showed the differential expression of some important genes related to metabolism, stress and pathogenesis, thereby AHL molecules up-regulate all tested genes, except phoU, while plant exudates induce only mxaF gene expression. In the presence of plant exudates there is a lower bacterial density (due the endophytic and epiphytic colonization, which produce less AHL, leading to down regulation of genes when compared to the control. Therefore, bacterial density, more than plant exudate, influences the expression of genes related to plant-bacteria interaction.

  2. Methylobacterium-plant interaction genes regulated by plant exudate and quorum sensing molecules.

    Science.gov (United States)

    Dourado, Manuella Nóbrega; Bogas, Andrea Cristina; Pomini, Armando M; Andreote, Fernando Dini; Quecine, Maria Carolina; Marsaioli, Anita J; Araújo, Welington Luiz

    2013-12-01

    Bacteria from the genus Methylobacterium interact symbiotically (endophytically and epiphytically) with different plant species. These interactions can promote plant growth or induce systemic resistance, increasing plant fitness. The plant colonization is guided by molecular communication between bacteria-bacteria and bacteria-plants, where the bacteria recognize specific exuded compounds by other bacteria (e.g. homoserine molecules) and/or by the plant roots (e.g. flavonoids, ethanol and methanol), respectively. In this context, the aim of this study was to evaluate the effect of quorum sensing molecules (N-acyl-homoserine lactones) and plant exudates (including ethanol) in the expression of a series of bacterial genes involved in Methylobacterium-plant interaction. The selected genes are related to bacterial metabolism (mxaF), adaptation to stressful environment (crtI, phoU and sss), to interactions with plant metabolism compounds (acdS) and pathogenicity (patatin and phoU). Under in vitro conditions, our results showed the differential expression of some important genes related to metabolism, stress and pathogenesis, thereby AHL molecules up-regulate all tested genes, except phoU, while plant exudates induce only mxaF gene expression. In the presence of plant exudates there is a lower bacterial density (due the endophytic and epiphytic colonization), which produce less AHL, leading to down regulation of genes when compared to the control. Therefore, bacterial density, more than plant exudate, influences the expression of genes related to plant-bacteria interaction. PMID:24688531

  3. Non-invasive analysis of root-soil interaction using three complementary imaging approaches

    Science.gov (United States)

    Haber-Pohlmeier, Sabina; Tötzke, Christian; Pohlmeier, Andreas; Rudolph-Mohr, Nicole; Kardjilov, Nikolay; Lehmann, Eberhard; Oswald, Sascha E.

    2016-04-01

    Plant roots are known to modify physical, chemical and biological properties of the rhizosphere, thereby, altering conditions for water and nutrient uptake. We aim for capturing the dynamic processes occurring at the soil-root interface in situ. A combination of neutron (NI), magnetic resonance (MRI) and micro-focus X-ray tomography (CT) is applied to monitor the rhizosphere of young plants grown in sandy soil in cylindrical containers (diameter 3 cm). A novel transportable low field MRI system is operated directly at the neutron facility allowing for combined measurements of the very same sample capturing the same hydro-physiological state. The combination of NI, MRI and CT provides three-dimensional access to the root system in respect to structure and hydraulics of the rhizosphere and the transport of dissolved marker substances. The high spatial resolution of neutron imaging and its sensitivity for water can be exploited for the 3D analysis of the root morphology and detailed mapping of three-dimensional water content at the root soil interface and the surrounding soil. MRI has the potential to yield complementary information about the mobility of water, which can be bound in small pores or in the polymeric network of root exudates (mucilage layer). We inject combined tracers (GdDPTA or D2O) to study water fluxes through soil, rhizosphere and roots. Additional CT measurements reveal mechanical impacts of roots on the local microstructure of soil, e.g. showing soil compaction or the formation of cracks. We co-register the NT, MRI and CT data to integrate the complementary information into an aligned 3D data set. This allows, e.g., for co-localization of compacted soil regions or cracks with the specific local soil hydraulics, which is needed to distinguish the contribution of root exudation from mechanical impacts when interpreting altered hydraulic properties of the rhizosphere. Differences between rhizosphere and bulk soil can be detected and interpreted in

  4. Facilitative root interactions in intercrops

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, H.; Jensen, E.S.

    2005-01-01

    Facilitation takes place when plants ameliorate the environment of their neighbours, and increase their growth and survival. Facilitation occurs in natural ecosystems as well as in agroecosystems. We discuss examples of facilitative root interactions in intercropped agroecosystems; including...... root architecture, exudation of growth stimulating substances, and biofumigation. Facilitative root interactions are most likely to be of importance in nutrient poor soils and in low-input agroecosystems due to critical interspecific competition for plant growth factors. However, studies from more...

  5. Changes of organic acid exudation and rhizosphere pH in rice plants under chromium stress

    International Nuclear Information System (INIS)

    The effect of chromium (Cr) stress on the changes of rhizosphere pH, organic acid exudation, and Cr accumulation in plants was studied using two rice genotypes differing in grain Cr accumulation. The results showed that rhizosphere pH increased with increasing level of Cr in the culture solution and with an extended time of Cr exposure. Among the six organic acids examined in this experiment, oxalic and malic acid contents were relatively higher, and had a significant positive correlation with the rhizosphere pH, indicating that they play an important role in changing rhizosphere pH. The Cr content in roots was significantly higher than that in stems and leaves. Cr accumulation in plants was significantly and positively correlated with rhizosphere pH, and the exudation of oxalic, malic and citric acids, suggesting that an increase in rhizosphere pH, and exudation of oxalic, malic and citric acid enhances Cr accumulation in rice plants. - Rhizosphere pH and organic acid exudation of rice roots are markedly affected by chromium level in culture solution

  6. Phloem exudation studies in selected woody trees

    Energy Technology Data Exchange (ETDEWEB)

    Costello, L.R.

    1980-10-01

    Chelating agents, particularly EDTA, were tested for their effectiveness in enhancing the exudation of phloem sugars from selected woody tree species. Of the species selected, Fraxinus uhdei (Evergreen Ash) proved most useful for exudation studies. Experiments using /sup 14/C labelled, excised leaflets of F. uhdei demonstrated that exudation was enhanced approximately 9-fold by a 2.0 mM EDTA treatment. An analysis of labelled products in the treatment solution showed that over 90% of label appeared in oligosaccharides and sucrose. These findings suggested that the sugars released into EDTA treatment solutions were principally derived from phloem sieve elements. Electron microscope studies of the fine structure of sieve plate pores after treatment with EDTA or H/sub 2/O showed substantially less callose appearing in sieve plates of leaflets treated with EDTA. It was proposed that EDTA enhances exudation by inhibiting or reducing callose formation in sieve plate pores. Subsequent experiments demonstrated that EDTA was effective in promoting exudation from whole plant specimens of F. uhdei as well as from excised leaflets. (MHR)

  7. Fine-tuning by strigolactones of root response to low phosphate

    Institute of Scientific and Technical Information of China (English)

    Yoram Kapulnik; Hinanit Koltai

    2016-01-01

    Strigolactones are plant hormones that regulate the development of different plant parts. In the shoot, they regulate axillary bud outgrowth and in the root, root architecture and root-hair length and density. Strigolactones are also involved with communication in the rhizosphere, including enhancement of hyphal branching of arbuscular mycorrhizal fungi. Here we present the role and activity of strigolactones under conditions of phosphate deprivation. Under these conditions, their levels of biosynthesis and exudation increase, leading to changes in shoot and root development. At least for the latter, these changes are likely to be associated with alterations in auxin transport and sensitivity. On the other hand, strigolactones may positively affect plant–mycorrhiza interactions and thereby promote phosphate acquisition by the plant. Strigolactones may be a way for plants to fine-tune their growth pattern under phosphate deprivation.

  8. Inhibition of tomato (Solanum lycopersicum L.) root growth by cyanamide is due to altered cell division, phytohormone balance and expansin gene expression.

    Science.gov (United States)

    Soltys, Dorota; Rudzińska-Langwald, Anna; Gniazdowska, Agnieszka; Wiśniewska, Anita; Bogatek, Renata

    2012-11-01

    Cyanamide (CA) has been reported as a natural compound produced by hairy vetch (Vicia villosa Roth.) and it was shown also to be an allelochemical, responsible for strong allelopathic potential in this species. CA phytotoxicity has been demonstrated on various plant species, but to date little is known about its mode of action at cellular level. Treatment of tomato (Solanum lycopersicum L.) roots with CA (1.2 mM) resulted in inhibition of growth accompanied by alterations in cell division, and imbalance of plant hormone (ethylene and auxin) homeostasis. Moreover, the phytotoxic effect of CA was also manifested by modifications in expansin gene expression, especially in expansins responsible for cell wall remodeling after the cytokinesis (LeEXPA9, LeEXPA18). Based on these results the phytotoxic activity of CA on growth of roots of tomato seedlings is likely due to alterations associated with cell division. PMID:22847024

  9. INSECTICIDAL TOXIN IN ROOT EXUDATES FROM BT CORN. (R826107)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  10. Amino acids in root exudates of Ambrosia artemisiifolia

    Czech Academy of Sciences Publication Activity Database

    Hohnová, Barbora; Moravcová, Dana; Figala, J.; Lvončík, S.; Lojková, Lea; Formánek, P.

    2015-01-01

    Roč. 47, - (2015), s. 1691-1691. ISSN 0939-4451. [International Congress on Amino Acids, Peptides and Proteins /14./. 03.08.2015-07.08.2015, Vienna] Institutional support: RVO:68081715 Keywords : PHWE * GC-MS * SDS-PAGE Subject RIV: CB - Analytical Chemistry, Separation

  11. Drought and root herbivory interact to alter the response of above-ground parasitoids to aphid infested plants and associated plant volatile signals

    OpenAIRE

    Muhammad Tariq; Wright, Denis J.; Bruce, Toby J. A.; Staley, Joanna T.

    2013-01-01

    Multitrophic interactions are likely to be altered by climate change but there is little empirical evidence relating the responses of herbivores and parasitoids to abiotic factors. Here we investigated the effects of drought on an above/below-ground system comprising a generalist and a specialist aphid species (foliar herbivores), their parasitoids, and a dipteran species (root herbivore).We tested the hypotheses that: (1) high levels of drought stress and below-ground herbivory interact to r...

  12. Contribution of Individual Chemoreceptors to Sinorhizobium meliloti Chemotaxis Towards Amino Acids of Host and Nonhost Seed Exudates.

    Science.gov (United States)

    Webb, Benjamin A; Helm, Richard F; Scharf, Birgit E

    2016-03-01

    Plant seeds and roots exude a spectrum of molecules into the soil that attract bacteria to the spermosphere and rhizosphere, respectively. The alfalfa symbiont Sinorhizobium meliloti utilizes eight chemoreceptors (McpT to McpZ and IcpA) to mediate chemotaxis. Using a modified hydrogel capillary chemotaxis assay that allows data quantification and larger throughput screening, we defined the role of S. meliloti chemoreceptors in sensing its host, Medicago sativa, and a closely related nonhost, Medicago arabica. S. meliloti wild type and most single-deletion strains displayed comparable chemotaxis responses to host or nonhost seed exudate. However, while the mcpZ mutant responded like wild type to M. sativa exudate, its reaction to M. arabica exudate was reduced by 80%. Even though the amino acid (AA) amounts released by both plant species were similar, synthetic AA mixtures that matched exudate profiles contributed differentially to the S. meliloti wild-type response to M. sativa (23%) and M. arabica (37%) exudates, with McpU identified as the most important chemoreceptor for AA. Our results show that S. meliloti is equally attracted to host and nonhost legumes; however, AA play a greater role in attraction to M. arabica than to M. sativa, with McpZ being specifically important in sensing M. arabica. PMID:26713349

  13. Staphylococcus hyicus virulence in relation to exudative epidermitis in pigs

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar; Andresen, Lars Ole; Bille-Hansen, Vivi

    1993-01-01

    Staphylococcus hyicus strains with different phage types, plasmid profiles, and antibiotic resistance patterns were isolated from piglets with exudative epidermitis. The strains could be divided into virulent strains, producing exudative epidermitis, and avirulent strains, producing no dermal...

  14. Methylobacterium-plant interaction genes regulated by plant exudate and quorum sensing molecules

    OpenAIRE

    Manuella Nóbrega Dourado; Andrea Cristina Bogas; Pomini, Armando M.; Fernando Dini Andreote; Maria Carolina Quecine; Marsaioli, Anita J.; Welington Luiz Araújo

    2013-01-01

    Bacteria from the genus Methylobacterium interact symbiotically (endophytically and epiphytically) with different plant species. These interactions can promote plant growth or induce systemic resistance, increasing plant fitness. The plant colonization is guided by molecular communication between bacteria-bacteria and bacteria-plants, where the bacteria recognize specific exuded compounds by other bacteria (e.g. homoserine molecules) and/or by the plant roots (e.g. flavonoids, ethanol and met...

  15. The presence of nodules on legume root systems can alter phenotypic plasticity in response to internal nitrogen independent of nitrogen fixation.

    Science.gov (United States)

    Goh, Chooi-Hua; Nicotra, Adrienne B; Mathesius, Ulrike

    2016-04-01

    All higher plants show developmental plasticity in response to the availability of nitrogen (N) in the soil. In legumes, N starvation causes the formation of root nodules, where symbiotic rhizobacteria fix atmospheric N2 for the host in exchange for fixed carbon (C) from the shoot. Here, we tested whether plastic responses to internal [N] of legumes are altered by their symbionts. Glasshouse experiments compared root phenotypes of three legumes, Medicago truncatula, Medicago sativa and Trifolium subterraneum, inoculated with their compatible symbiont partners and grown under four nitrate levels. In addition, six strains of rhizobia, differing in their ability to fix N2 in M. truncatula, were compared to test if plastic responses to internal [N] were dependent on the rhizobia or N2 -fixing capability of the nodules. We found that the presence of rhizobia affected phenotypic plasticity of the legumes to internal [N], particularly in root length and root mass ratio (RMR), in a plant species-dependent way. While root length responses of M. truncatula to internal [N] were dependent on the ability of rhizobial symbionts to fix N2 , RMR response to internal [N] was dependent only on initiation of nodules, irrespective of N2 -fixing ability of the rhizobia strains. PMID:26523414

  16. Phylloxera (Daktulosphaira vitifoliae Fitch) alters the carbohydrate metabolism in root galls to allowing the compatible interaction with grapevine (Vitis ssp.) roots

    OpenAIRE

    Griesser, Michaela; Lawo, Nora Caroline; Crespo-Martinez, Sara; Schoedl-Hummel, Katharina; Wieczorek, Krzysztof; Gorecka, Miroslawa; Liebner, Falk; Zweckmair, Thomas; Stralis Pavese, Nancy; Kreil, David; Forneck, Astrid

    2015-01-01

    Gall forming phylloxera may compete for nutrients with meristematic tissues and develop heterotrophic structures that act as carbon sinks. In this work, we studied the underlying starch metabolism, sink-source translocation of soluble sugars towards and within root galls. We demonstrated that nodosities store carbohydrates by starch accumulation and monitored the expression of genes involved in the starch metabolic. Thereby we proved that the nodosity is symplastically connected to the source...

  17. Exudation of organic acids by a marsh plant and implications on trace metal availability in the rhizosphere of estuarine sediments

    Science.gov (United States)

    Mucha, Ana P.; Almeida, C. Marisa R.; Bordalo, Adriano A.; Vasconcelos, M. Teresa S. D.

    2005-10-01

    The aim of this work was to identify a variety of low molecular weight organic acids exuded by the sea rush Juncus maritimus collected at two locations with different sediment characteristics (sandy and muddy) and to examine whether specific differences in physico-chemical sediment characteristics influenced plant exudation. Just after collection, plant roots were rinsed and put in contact with deionised water for 2 h. In the obtained solution the organic acids, exuded by the plants, were determined by high performance liquid chromatography. Juncus maritimus was shown to be capable of releasing malonate and oxalate. Sediments and rhizosediments (sediment in contact with the plant roots and rhizomes, corresponding to the area of higher belowground biomass) from the areas where the plants had been collected were characterised in terms of physical and chemical composition, including acid volatile sulphide and total-recoverable metals (Pb, Cr, Cu, Zn, Ni and Cd). It was found that the extent of exudation varied markedly between sites. The identified organic acids were used as extractants of metals from sediments and rhizosediments and the results were compared with those provided by a very commonly used sequential extraction approach, which was carried out in parallel. This work demonstrates that J. maritimus can release organic compounds that can act as complexing agents of trace metal and therefore organic exudates should be accounted for when dealing with estuarine environment quality.

  18. Genetics Home Reference: familial exudative vitreoretinopathy

    Science.gov (United States)

    ... 2):104-12. Citation on PubMed Robitaille J, MacDonald ML, Kaykas A, Sheldahl LC, Zeisler J, Dubé ... Shukla D, Singh J, Sudheer G, Soman M, John RK, Ramasamy K, Perumalsamy N. Familial exudative vitreoretinopathy ( ...

  19. Naturally-assisted metal phytoextraction by Brassica carinata: Role ofroot exudates

    International Nuclear Information System (INIS)

    Due to relatively high chelant dosages and potential environmental risks it is necessary to explore different approaches in the remediation of metal-contaminated soils. The present study focussed on the removal of metals (As, Cd, Cu, Pb and Zn) from a multiple metal-contaminated soil by growing Brassica carinata plants in succession to spontaneous metallicolous populations of Pinus pinaster, Plantago lanceolata and Silene paradoxa. The results showed that the growth of the metallicolous populations increased the extractable metal levels in the soil, which resulted in a higher accumulation of metals in the above-ground parts of B. carinata. Root exudates of the three metallicolous species were analysed to elucidate their possible role in the enhanced metal availability. The presence of metals stimulated the exudation of organic and phenolic acids as well as flavonoids. It was suggested that root exudates played an important role in solubilising metals in soil and in favouring their uptake by roots. - Phytoextraction of metals is enhanced in Brassica carinata grown in succession to metallicolous populations of spontaneous species.

  20. Altered Phenylpropanoid Metabolism in the Maize Lc-Expressed Sweet Potato (Ipomoea batatas) Affects Storage Root Development.

    Science.gov (United States)

    Wang, Hongxia; Yang, Jun; Zhang, Min; Fan, Weijuan; Firon, Nurit; Pattanaik, Sitakanta; Yuan, Ling; Zhang, Peng

    2016-01-01

    There is no direct evidence of the effect of lignin metabolism on early storage root development in sweet potato. In this study, we found that heterologous expression of the maize leaf color (Lc) gene in sweet potato increased anthocyanin pigment accumulation in the whole plant and resulted in reduced size with an increased length/width ratio, low yield and less starch content in the early storage roots. RT-PCR analysis revealed dramatic up-regulation of the genes involved in the lignin biosynthesis pathway in developing storage roots, leading to greater lignin content in the Lc transgenic lines, compared to the wild type. This was also evidenced by the enhanced lignification of vascular cells in the early storage roots. Furthermore, increased expression of the β-amylase gene in leaves and storage roots also accelerated starch degradation and increased the sugar use efficiency, providing more energy and carbohydrate sources for lignin biosynthesis in the Lc transgenic sweet potato. Lesser starch accumulation was observed in the developing storage roots at the initiation stage in the Lc plants. Our study provides experimental evidence of the basic carbohydrate metabolism underlying the development of storage roots, which is the transformation of lignin biosynthesis to starch biosynthesis. PMID:26727353

  1. Influence of coral and algal exudates on microbially mediated reef metabolism

    Directory of Open Access Journals (Sweden)

    Andreas F. Haas

    2013-07-01

    Full Text Available Benthic primary producers in tropical reef ecosystems can alter biogeochemical cycling and microbial processes in the surrounding seawater. In order to quantify these influences, we measured rates of photosynthesis, respiration, and dissolved organic carbon (DOC exudate release by the dominant benthic primary producers (calcifying and non-calcifying macroalgae, turf-algae and corals on reefs of Mo‘orea French Polynesia. Subsequently, we examined planktonic and benthic microbial community response to these dissolved exudates by measuring bacterial growth rates and oxygen and DOC fluxes in dark and daylight incubation experiments. All benthic primary producers exuded significant quantities of DOC (roughly 10% of their daily fixed carbon into the surrounding water over a diurnal cycle. The microbial community responses were dependent upon the source of the exudates and whether the inoculum of microbes included planktonic or planktonic plus benthic communities. The planktonic and benthic microbial communities in the unamended control treatments exhibited opposing influences on DO concentration where respiration dominated in treatments comprised solely of plankton and autotrophy dominated in treatments with benthic plus plankon microbial communities. Coral exudates (and associated inorganic nutrients caused a shift towards a net autotrophic microbial metabolism by increasing the net production of oxygen by the benthic and decreasing the net consumption of oxygen by the planktonic microbial community. In contrast, the addition of algal exudates decreased the net primary production by the benthic communities and increased the net consumption of oxygen by the planktonic microbial community thereby resulting in a shift towards net heterotrophic community metabolism. When scaled up to the reef habitat, exudate-induced effects on microbial respiration did not outweigh the high oxygen production rates of benthic algae, such that reef areas dominated with

  2. Leachability of volatile fuel compounds from contaminated soils and the effect of plant exudates: A comparison of column and batch leaching tests.

    Science.gov (United States)

    Balseiro-Romero, María; Kidd, Petra S; Monterroso, Carmen

    2016-03-01

    Volatile fuel compounds such as fuel oxygenates (FO) (MTBE and ETBE) and BTEX (benzene, toluene, ethylbenzene and xylene) are some of the most soluble components of fuel. Characterizing the leaching potential of these compounds is essential for predicting their mobility through the soil profile and assessing the risk of groundwater contamination. Plant root exudates can play an important role in the modification of contaminant mobility in soil-plant systems, and such effects should also be considered in leaching studies. Artificially spiked samples of A and B horizons from an alumi-umbric Cambisol were leached in packed-columns and batch experiments using Milli-Q water and plant root exudates as leaching agents. The leaching potential and rate were strongly influenced by soil-contaminant interactions and by the presence of root exudates. Organic matter in A horizon preferably sorbed the most non-polar contaminants, lowering their leaching potential, and this effect was enhanced by the presence of root exudates. On the other hand, the inorganic components of the B horizon, showed a greater affinity for polar molecules, and the presence of root exudates enhanced the desorption of the contaminants. Column experiments resulted in a more realistic protocol than batch tests for predicting the leaching potential of volatile organic compounds in dissimilar soils. PMID:26619047

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    Organic fertilization is well known to affect individual functional groups of root associated fungi such as arbuscular mycorrhizal (AM) fungi and root pathogens, but limited information is available on the effect of organic fertilization at the fungal community composition level. The main objective...... of the present study was to examine the response of communities of root associated fungi in Pisum sativum to Protamylasse, an organic fertilizer used in pea production. Plants were grown in pots with field soil amended with four different levels of Protamylasse. 454 pyrosequencing was employed to...... examine diversity of root associated fungi and revealed in total 164 non-singleton operational taxonomic units (OTUs). Principle component analysis (PCA) showed response of fungal community structure of the 15 most abundant OTUs to the four fertilization levels. Obligate biotrophic fungi such as the AM...

  4. Toxicity of canavanine in tomato (Solanum lycopersicum L.) roots is due to alterations in RNS, ROS and auxin levels.

    Science.gov (United States)

    Krasuska, Urszula; Andrzejczak, Olga; Staszek, Paweł; Borucki, Wojciech; Gniazdowska, Agnieszka

    2016-06-01

    Canavanine (CAN) is non-proteinogenic aminoacid and a structural analog of arginine (Arg). Naturally, CAN occurs in legumes e.g. jack bean and is considered as a strong allelochemical. As a selective inhibitor of inducible nitric oxide synthase in mammalians, it could act as a modifier of nitric oxide (NO) concentration in plants. Modifications in the content of endogenous reactive nitrogen species (RNS) and reactive oxygen species (ROS) influence root structure and architecture, being also under hormonal control. The aim of the work was to investigate regulation of root growth in tomato (Solanum lycopersicum L. cv. Malinowy Ożarowski) seedling by application of CAN at concentration (10 and 50 μM) leading to 50% or 100% restriction of root elongation. CAN at higher concentration led to slight DNA fragmentation, increased total RNA and protein level. Decline in total respiration rate after CAN supplementation was not associated with enhanced membrane permeability. Malformations in root morphology (shorter and thicker roots, limited number of lateral roots) were accompanied by modification in NO and ONOO(-) localization; determined mainly in peridermal cells and some border cells. Although, CAN resulted in low RNS production, addition of exogenous NO by usage of NO donors did not reverse its negative effect, nor recovery effect was detected after roots imbibition in Arg. To build up a comprehensive view on mode of action of CAN as root growth inhibitor, it was shown an elevated level of auxin. To summarize, we demonstrated several secondary mode of action of CAN, indicating its toxicity in plants linked to restriction in RNS formation accompanied by simultaneous overaccumulation of ROS. PMID:26986929

  5. Multitrophic Interaction in the Rhizosphere of Maize: Root Feeding of Western Corn Rootworm Larvae Alters the Microbial Community Composition

    OpenAIRE

    Dematheis, Flavia; Zimmerling, Ute; Flocco, Cecilia; Kurtz, Benedikt; Vidal, Stefan; Kropf, Siegfried; Smalla, Kornelia

    2012-01-01

    Background: Larvae of the Western Corn Rootworm (WCR) feeding on maize roots cause heavy economical losses in the US and in Europe. New or adapted pest management strategies urgently require a better understanding of the multitrophic interaction in the rhizosphere. This study aimed to investigate the effect of WCR root feeding on the microbial communities colonizing the maize rhizosphere. Methodology/Principal Findings: In a greenhouse experiment, maize lines KWS13, KWS14, KWS15 a...

  6. Alterations in cytosol free calcium in horseradish roots simultaneously exposed to lanthanum(III) and acid rain.

    Science.gov (United States)

    Zhang, Xuanbo; Wang, Lihong; Zhou, Anhua; Zhou, Qing; Huang, Xiaohua

    2016-04-01

    The extensive use of rare earth elements (REEs) has increased their environmental levels. REE pollution concomitant with acid rain in many agricultural regions can affect crop growth. Cytosol free calcium ions (Ca(2+)) play an important role in almost all cellular activities. However, no data have been reported regarding the role of cytosol free Ca(2+) in plant roots simultaneously exposed to REE and acid rain. In this study, the effects of exposures to lanthanum(III) and acid rain, independently and in combination, on cytosol free Ca(2+) levels, root activity, metal contents, biomass, cytosol pH and La contents in horseradish roots were investigated. The simultaneous exposures to La(III) and acid rain increased or decreased the cytosol free Ca(2+) levels, depending on the concentration of La(III), and these effects were more evident than independent exposure to La(III) or acid rain. In combined exposures, cytosol free Ca(2+) played an important role in the regulation of root activity, metal contents and biomass. These roles were closely related to La(III) dose, acid rain strength and treatment mode (independent exposure or simultaneous exposure). A low concentration of La(III) (20 mg L(-1)) could alleviate the adverse effects on the roots caused by acid rain, and the combined exposures at higher concentrations of La(III) and acid rain had synergic effects on the roots. PMID:26720810

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

    Science.gov (United States)

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

    2016-01-01

    The interaction between roots and bacterial communities in halophytic species is poorly understood. Here, we used Jerusalem artichoke cultivar Nanyu 1 (NY-1) to characterise root distribution patterns and determine diversity and abundance of bacteria in the rhizosphere soil under variable salinity. Root growth was not inhibited within the salinity range 1.2 to 1.9 g salt/kg, but roots were mainly confined to 0-20 cm soil layer vertically and 0-30 cm horizontally from the plant centre. Root concentrations of K(+), Na(+), Mg(2+) and particularly Ca(2+) were relatively high under salinity stress. High salinity stress decreased soil invertase and catalase activity. Using a next-generation, Illumina-based sequencing approach, we determined higher diversity of bacteria in the rhizosphere soil at high than low salinity. More than 15,500 valid reads were obtained, and Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria predominated in all samples, accounting for >80% of the reads. On a genus level, 636 genera were common to the low and high salinity treatments at 0-5 cm and 5-10 cm depth. The abundance of Steroidobacter and Sphingomonas was significantly decreased by increasing salinity. Higher Shannon and Chao 1 indices with increasing severity of salt stress indicated that high salt stress increased diversity in the bacterial communities. PMID:26852800

  8. Cadmium Toxicity Induced Alterations in the Root Proteome of Green Gram in Contrasting Response towards Iron Supplement

    Directory of Open Access Journals (Sweden)

    Sowbiya Muneer

    2014-04-01

    Full Text Available Cadmium signifies a severe threat to crop productivity and green gram is a notably iron sensitive plant which shows considerable variation towards cadmium stress. A gel-based proteomics analysis was performed with the roots of green gram exposed to iron and cadmium combined treatments. The resulting data show that twenty three proteins were down-regulated in iron-deprived roots either in the absence (−Fe/−Cd or presence (−Fe/+Cd of cadmium. These down-regulated proteins were however well expressed in roots under iron sufficient conditions, even in the presence of cadmium (+Fe/+Cd. The functional classification of these proteins determined that 21% of the proteins are associated with nutrient metabolism. The other proteins in higher quantities are involved in either transcription or translation regulation, and the rest are involved in biosynthesis metabolism, antioxidant pathways, molecular chaperones and stress response. On the other hand, several protein spots were also absent in roots in response to iron deprivation either in absence (−Fe/−Cd or presence (−Fe/+Cd of cadmium but were well expressed in the presence of iron (+Fe/+Cd. Results suggest that green gram plants exposed to cadmium stress are able to change the nutrient metabolic balance in roots, but in the mean time regulate cadmium toxicity through iron supplements.

  9. Improvement of Growth and Periplocin Yield of Periploca sepium Adventitious Root Cultures by Altering Nitrogen Source Supply

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian; GAO Wen-yuan; WANG Juan; LI Xing-lin; XIAO Pei-gen

    2011-01-01

    Objective To increase the ultimate yield of periplocin in Periploca sepium adventitious root cultures by a two-stage culture based on nitrogen source.Methods Firstly,the effects of nitrogen source(NH-NO-)at different ratios and different total initial nitrogen amounts on the accumulation of biomass and secondary metabolites in adventitious root cultures of P sepium were investigated,and growth and production media for the two-stage culture based on the above results were established.Results The highest biomass and periplocin content were obtained in the culture medium of 15 mmol/L total nitrogen amount with NH-NO(1:2)and 30 mmol/L total nitrogen amount with nitrate as the sole nitrogen source.By adopting a fed-batch cultivation strategy,the dry weight adventitious root,periplocin content and yield were increased by 136%,108%,and 389%,respectively when compared with those of the control,reaching up to 8.13 g/L,157.15 μg/g,and 1277.63 μg/L,respectively.Furthermore,it was found that in the process of two-stage culture,the adventitious roots grew thicker significantly after they were transferred into production medium directly.Conclusion The ultimate yield of periplocin in P.sepium adventitious root cultures could be significantly increased by a two-stage culture based on nitrogen source.

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

    Science.gov (United States)

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

    2016-01-01

    The interaction between roots and bacterial communities in halophytic species is poorly understood. Here, we used Jerusalem artichoke cultivar Nanyu 1 (NY-1) to characterise root distribution patterns and determine diversity and abundance of bacteria in the rhizosphere soil under variable salinity. Root growth was not inhibited within the salinity range 1.2 to 1.9 g salt/kg, but roots were mainly confined to 0–20 cm soil layer vertically and 0–30 cm horizontally from the plant centre. Root concentrations of K+, Na+, Mg2+ and particularly Ca2+ were relatively high under salinity stress. High salinity stress decreased soil invertase and catalase activity. Using a next-generation, Illumina-based sequencing approach, we determined higher diversity of bacteria in the rhizosphere soil at high than low salinity. More than 15,500 valid reads were obtained, and Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria predominated in all samples, accounting for >80% of the reads. On a genus level, 636 genera were common to the low and high salinity treatments at 0–5 cm and 5–10 cm depth. The abundance of Steroidobacter and Sphingomonas was significantly decreased by increasing salinity. Higher Shannon and Chao 1 indices with increasing severity of salt stress indicated that high salt stress increased diversity in the bacterial communities. PMID:26852800

  11. Canavanine Alters ROS/RNS Level and Leads to Post-translational Modification of Proteins in Roots of Tomato Seedlings

    Science.gov (United States)

    Krasuska, Urszula; Andrzejczak, Olga; Staszek, Paweł; Bogatek, Renata; Gniazdowska, Agnieszka

    2016-01-01

    Canavanine (CAN), a structural analog of arginine (Arg), is used as a selective inhibitor of inducible NOS in mammals. CAN is incorporated into proteins’ structure in the place of Arg, leading to the formation of aberrant compounds. This non-protein amino acid is found in legumes, e.g., Canavalia ensiformis (L.) DC. or Sutherlandia frutescens (L.) R.Br. and acts as a strong toxin against herbivores or plants. Tomato (Solanum lycopersicum L.) seedlings were treated for 24–72 h with CAN (10 or 50 μM) inhibiting root growth by 50 or 100%, without lethal effect. We determined ROS level/production in root extracts, fluorescence of DAF-FM and APF derivatives corresponding to RNS level in roots of tomato seedlings and linked CAN-induced restriction of root growth to the post-translational modifications (PTMs) of proteins: carbonylation and nitration. Both PTMs are stable markers of nitro-oxidative stress, regarded as the plant’s secondary response to phytotoxins. CAN enhanced H2O2 content and superoxide radicals generation in extracts of tomato roots and stimulated formation of protein carbonyl groups. An elevated level of carbonylated proteins was characteristic for the plants after 72 h of the culture, mainly for the roots exposed to 10 μM CAN. The proteolytic activity was stimulated by tested non-protein amino acid. CAN treatment led to decline of fluorescence of DAF-FM derivatives, and transiently stimulated fluorescence of APF derivatives. Short-term exposure of tomato seedlings to CAN lowered the protein nitration level. Activity of peroxidase, polyamine oxidase and NADPH oxidase, enzymes acting as modulators of H2O2 concentration and governing root architecture and growth were determined. Activities of all enzymes were stimulated by CAN, but no strict CAN concentration dependence was observed. We conclude, that although CAN treatment led to a decline in the nitric oxide level, PTMs observed in roots of plants exposed to CAN are linked rather to the

  12. Canavanine Alters ROS/RNS Level and Leads to Post-translational Modification of Proteins in Roots of Tomato Seedlings.

    Science.gov (United States)

    Krasuska, Urszula; Andrzejczak, Olga; Staszek, Paweł; Bogatek, Renata; Gniazdowska, Agnieszka

    2016-01-01

    Canavanine (CAN), a structural analog of arginine (Arg), is used as a selective inhibitor of inducible NOS in mammals. CAN is incorporated into proteins' structure in the place of Arg, leading to the formation of aberrant compounds. This non-protein amino acid is found in legumes, e.g., Canavalia ensiformis (L.) DC. or Sutherlandia frutescens (L.) R.Br. and acts as a strong toxin against herbivores or plants. Tomato (Solanum lycopersicum L.) seedlings were treated for 24-72 h with CAN (10 or 50 μM) inhibiting root growth by 50 or 100%, without lethal effect. We determined ROS level/production in root extracts, fluorescence of DAF-FM and APF derivatives corresponding to RNS level in roots of tomato seedlings and linked CAN-induced restriction of root growth to the post-translational modifications (PTMs) of proteins: carbonylation and nitration. Both PTMs are stable markers of nitro-oxidative stress, regarded as the plant's secondary response to phytotoxins. CAN enhanced H2O2 content and superoxide radicals generation in extracts of tomato roots and stimulated formation of protein carbonyl groups. An elevated level of carbonylated proteins was characteristic for the plants after 72 h of the culture, mainly for the roots exposed to 10 μM CAN. The proteolytic activity was stimulated by tested non-protein amino acid. CAN treatment led to decline of fluorescence of DAF-FM derivatives, and transiently stimulated fluorescence of APF derivatives. Short-term exposure of tomato seedlings to CAN lowered the protein nitration level. Activity of peroxidase, polyamine oxidase and NADPH oxidase, enzymes acting as modulators of H2O2 concentration and governing root architecture and growth were determined. Activities of all enzymes were stimulated by CAN, but no strict CAN concentration dependence was observed. We conclude, that although CAN treatment led to a decline in the nitric oxide level, PTMs observed in roots of plants exposed to CAN are linked rather to the formation of

  13. Altered Phenylpropanoid Metabolism in the Maize Lc-Expressed Sweet Potato (Ipomoea batatas) Affects Storage Root Development

    OpenAIRE

    Hongxia Wang; Jun Yang; Min Zhang; Weijuan Fan; Nurit Firon; Sitakanta Pattanaik; Ling Yuan; Peng Zhang

    2016-01-01

    There is no direct evidence of the effect of lignin metabolism on early storage root development in sweet potato. In this study, we found that heterologous expression of the maize leaf color (Lc) gene in sweet potato increased anthocyanin pigment accumulation in the whole plant and resulted in reduced size with an increased length/width ratio, low yield and less starch content in the early storage roots. RT-PCR analysis revealed dramatic up-regulation of the genes involved in the lignin biosy...

  14. Clinical case of exudative pleuritis in stallion

    International Nuclear Information System (INIS)

    A casual exudative pleuritis in 2 years old stallion, Holsteiner breed, has been outlined. The disease is extremely rare in this country. Comprehensive examinations have been made during the period of hospitalization: daily clinical examinations, double renthgenography; regular haematological and biochemical tests; microbiological culture tests with an antibioticogram; laboratory tests of punctate and periodical ultrasound tests. The examinations and tests have been carried out at the Internal Noncontagious Disease Clinic at the Veterinary Faculty of the Thracian University in Stara Zagora

  15. Chickenpox Chorioretinitis with Retinal Exudates and Periphlebitis

    Directory of Open Access Journals (Sweden)

    Hirokuni Kitamei

    2012-05-01

    Full Text Available Background: Chickenpox is rarely associated with posterior segment inflammation. We report on a case of unilateral chickenpox chorioretinitis with retinal exudates and periphlebitis. Case Presentation: A 21-year-old healthy man, who suffered from chickenpox 2 weeks prior to symptom development, exhibited mild anterior chamber cells, vitreous opacity, sheathing of retinal veins, and yellow-white exudates in his right eye. Varicella zoster virus DNA was detected by polymerase chain reaction in the aqueous humor. He was treated with intravenous acyclovir followed by oral prednisolone and valaciclovir. Aqueous cells quickly disappeared and retinal exudates diminished within 1 month, leaving faint retinal scarring. Retinal arteritis had never been observed in this patient. Conclusions: Although the ocular findings in this case were similar to acute retinal necrosis (ARN, the clinical features differed from ARN in the following points: (1 mild anterior chamber inflammation, (2 absence of retinal arteritis, and (3 prompt resolution of inflammatory findings. The distinctive clinical features indicated that chorioretinitis associated with chickenpox may not have the same pathological conditions as ARN.

  16. Inhibition of tomato (Solanum lycopersicum L.) root growth by cyanamide is due to altered cell division, phytohormone balance and expansin gene expression

    OpenAIRE

    Soltys, Dorota; Rudzińska-Langwald, Anna; Gniazdowska, Agnieszka; Wiśniewska, Anita; Bogatek, Renata

    2012-01-01

    Cyanamide (CA) has been reported as a natural compound produced by hairy vetch (Vicia villosa Roth.) and it was shown also to be an allelochemical, responsible for strong allelopathic potential in this species. CA phytotoxicity has been demonstrated on various plant species, but to date little is known about its mode of action at cellular level. Treatment of tomato (Solanum lycopersicum L.) roots with CA (1.2 mM) resulted in inhibition of growth accompanied by alterations in cell division, an...

  17. Phragmites australis response to Cu in terms of low molecular weight organic acids (LMWOAs) exudation: Influence of the physiological cycle

    Science.gov (United States)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2014-06-01

    Plant roots have the ability to produce and secrete substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere for several purposes, including in response to metal contamination. Despite this, little is yet known about the exudation of such substances from marsh plants roots in response to metal exposure. This work aimed at assessing the influence of the physiological cycle of marsh plants on the exudation of ALMWOAs in response to Cu contamination. In vitro experiments were carried out with Phragmites australis specimens, collected in different seasons. Plant roots were exposed to freshwater contaminated with two different Cu concentrations (67 μg/L and 6.9 mg/L), being the ALMWOAs released by the roots measured. Significant differences (both qualitative and quantitative) were observed during the Phragmites australis life cycle. At growing stage, Cu stimulated the exudation of oxalic and formic acids but no significant stimulation was observed for citric acid. At developing stage, exposure to Cu caused inhibition of oxalic acid exudation whereas citric acid liberation was stimulated but only in the media spiked with the lowest Cu concentration tested. At the decaying stage, no significant variation on oxalic acid was observed, whereas the citric and formic acids release increased as a consequence of the plant exposure to Cu. The physiological cycle of Phragmites australis, and probably also of other marsh plants, is therefore an important feature conditioning plants response to Cu contamination, in terms of ALMWOAs exudation. Hence this aspect should be considered when conducting studies on rhizodeposition involving marsh plants exposed to metals and in the event of using marsh plants for phytoremediation purposes in contaminated estuarine areas.

  18. Model system for studies of microbial dynamics at exuding surfaces such as the rhizosphere

    Science.gov (United States)

    Odham, G.; Tunlid, A.; Valeur, A.; Sundin, P.; White, D. C.

    1986-01-01

    An autoclavable all-glass system for studying microbial dynamics at permeable surfaces is described. Standard hydrophobic or hydrophilic membranes (46-mm diameter) of various pore sizes were supported on a glass frit through which nutrient solutions were pumped by a peristaltic pump. The pump provided a precisely controlled flow at speeds of 0.5 to 500 ml of defined or natural cell exudates per h, which passed through the membrane into a receiving vessel. The construction allowed a choice of membranes, which could be modified. The system was tested with a bacterium, isolated from rape plant roots (Brassica napus L.), that was inoculated on a hydrophilic membrane filter and allowed to develop into a biofilm. A defined medium with a composition resembling that of natural rape root exudate was pumped through the membrane at 0.5 ml/h. Scanning electron microscopic examinations indicated that the inoculum formed microcolonies embedded in exopolymers evenly distributed over the membrane surface. The lipid composition and content of poly-beta-hydroxybutyrate in free-living and adhered cells were determined by gas chromatography. The bacterial consumption of amino acids in the exudate was also studied.

  19. Phylloxera (Daktulosphaira vitifoliae Fitch) alters the carbohydrate metabolism in root galls to allowing the compatible interaction with grapevine (Vitis ssp.) roots.

    Science.gov (United States)

    Griesser, Michaela; Lawo, Nora Caroline; Crespo-Martinez, Sara; Schoedl-Hummel, Katharina; Wieczorek, Krzysztof; Gorecka, Miroslawa; Liebner, Falk; Zweckmair, Thomas; Stralis Pavese, Nancy; Kreil, David; Forneck, Astrid

    2015-05-01

    Gall forming phylloxera may compete for nutrients with meristematic tissues and develop heterotrophic structures that act as carbon sinks. In this work, we studied the underlying starch metabolism, sink-source translocation of soluble sugars towards and within root galls. We demonstrated that nodosities store carbohydrates by starch accumulation and monitored the expression of genes involved in the starch metabolic. Thereby we proved that the nodosity is symplastically connected to the source tissues through its development and that the starch metabolism is significantly affected to synthesize and degrade starch within the gall. Genes required for starch biosynthesis and degradation are up-regulated. Among the carbohydrate transporters the expression of a glucose-6-phosphate translocater, one sucrose transporter and two SWEET proteins were increases, whereas hexose transporters, tonoplast monosaccharide transporter and Erd6-like sugar transporters were decreased. We found general evidence for plant response to osmotic stress in the nodosity as previously suggested for gall induction processes. We conclude that nodosities are heterogenous plant organs that accumulate starch to serve as temporary storage structure that is gradually withdrawn by phylloxera. Phylloxera transcriptionally reprograms gall tissues beyond primary metabolism and included downstream secondary processes, including response to osmotic stress. PMID:25804808

  20. Variation among Rice Cultivars in Root Acidification and Its Relation to Cadmium Uptake

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-guo; XU Hai; CAI Guo-liang; QIAN Min; WANG De-ke; ZHU Qing-sen

    2006-01-01

    To understand the mechanisms of Cd uptake and accumulation in rice, soil acidification by root activities was investigated in six rice cultivars differing in Cd accumulation. The results showed a significant difference among the cultivars in pH of pot water and root exudate. Soil acidification abilities varied with rice cultivars. Both pH of pot water and root exudate were lower in indica cultivars than in japonica ones. The difference in root acidification was larger in Cd treated cultivars than the control. Under Cd stress, the pH of pot water and root exudate correlated negatively and significantly with Cd concentrations in rice plants. It was suggested that the soil acidification by root exudates, especially in Cd contaminated soils, may be one of the mechanisms responsible for Cd uptake in rice cultivars.

  1. Evaluation of the morphological alteration of the root surface radiated with a diode laser; Avaliacao da alteracao morfologica da superficie cimentaria irradiada com laser de diodo

    Energy Technology Data Exchange (ETDEWEB)

    Gulin, Mauricio

    2003-07-01

    The diode laser has been studied for periodontal therapy, as much for removal of calculus as for microbial reduction of periodontal pockets, as well as the visible analgesic effects and biomodulation capacity. For this reason the purpose of this study was to evaluate the morphological alteration of the root surface after radiation with the diode laser, 808 nm through analysis by scanning electron microscopy (SEM). Besides this, to verify the temperature variations caused during the radiation, a thermometer put into the dentinal wall of the root canal was used. In all, 18 teeth were used, 15 of which for the SEM study, and the other 3 were used to temperature variation analysis. The 25 samples were scraped on the root surface and planed with manual instruments. The other 5 were not subjected to any type of treatment. This, 6 groups of 5 samples each were formed. Control Group C whose samples had not received any treatment; Control Group C 1 was only scraped and polished conventionally with Hu-Friedy Gracey curettes 5 and 6; the other samples groups L1, L2, L3, L4 were radiated by diode laser using parameters of power 1,0 W; 1,2 W; 1,4 W; and 1,6 W respectively, 2 times for 10 seconds with 20 seconds intervals between each radiation in continuous mode. The results with relation to the increase of temperature in the interior of the root canal demonstrated that there was an increase of more than 5 degree Celsius. The results of the scanning electron microscope analysis of Control Group C demonstrated great irregularity and ridges on the root surface, with the presence of a dentine layer. Control Group C1 presented a similar aspect to Group L 1's, smoother and more homogeneous surface. Groups L2, L3, and L4 presented scratches alternating with smoother areas showing that fiber contacted the surface of the sample. The results reconfirmed the necessity of further studies using diode laser, with a beam of light emitted in an interrupted mode to improve the control of

  2. Response of Arabidopsis thaliana Roots with Altered Lipid Transfer Protein (LTP) Gene Expression to the Clubroot Disease and Salt Stress

    OpenAIRE

    Sabine Jülke; Jutta Ludwig-Müller

    2015-01-01

    The clubroot disease of Brassicaceae is caused by the obligate biotrophic protist Plasmodiophora brassicae. The disease is characterized by abnormal tumorous swellings of infected roots that result in reduced drought resistance and insufficient distribution of nutrients, leading to reduced crop yield. It is one of the most damaging diseases among cruciferous crops worldwide. The acquisition of nutrients by the protist is not well understood. Gene expression profiles in Arabidopsis thaliana cl...

  3. Response of Arabidopsis thaliana Roots with Altered Lipid Transfer Protein (LTP) Gene Expression to the Clubroot Disease and Salt Stress.

    Science.gov (United States)

    Jülke, Sabine; Ludwig-Müller, Jutta

    2015-01-01

    The clubroot disease of Brassicaceae is caused by the obligate biotrophic protist Plasmodiophora brassicae. The disease is characterized by abnormal tumorous swellings of infected roots that result in reduced drought resistance and insufficient distribution of nutrients, leading to reduced crop yield. It is one of the most damaging diseases among cruciferous crops worldwide. The acquisition of nutrients by the protist is not well understood. Gene expression profiles in Arabidopsis thaliana clubroots indicate that lipid transfer proteins (LTPs) could be involved in disease development or at least in adaptation to the disease symptoms. Therefore, the aim of the study was to examine the role of some, of the still enigmatic LTPs during clubroot development. For a functional approach, we have generated transgenic plants that overexpress LTP genes in a root specific manner or show reduced LTP gene expression. Our results showed that overexpression of some of the LTP genes resulted in reduced disease severity whereas the lipid content in clubs of LTP mutants seems to be unaffected. Additional studies indicate a role for some LTPs during salt stress conditions in roots of A. thaliana. PMID:27135222

  4. Response of Arabidopsis thaliana Roots with Altered Lipid Transfer Protein (LTP Gene Expression to the Clubroot Disease and Salt Stress

    Directory of Open Access Journals (Sweden)

    Sabine Jülke

    2015-12-01

    Full Text Available The clubroot disease of Brassicaceae is caused by the obligate biotrophic protist Plasmodiophora brassicae. The disease is characterized by abnormal tumorous swellings of infected roots that result in reduced drought resistance and insufficient distribution of nutrients, leading to reduced crop yield. It is one of the most damaging diseases among cruciferous crops worldwide. The acquisition of nutrients by the protist is not well understood. Gene expression profiles in Arabidopsis thaliana clubroots indicate that lipid transfer proteins (LTPs could be involved in disease development or at least in adaptation to the disease symptoms. Therefore, the aim of the study was to examine the role of some, of the still enigmatic LTPs during clubroot development. For a functional approach, we have generated transgenic plants that overexpress LTP genes in a root specific manner or show reduced LTP gene expression. Our results showed that overexpression of some of the LTP genes resulted in reduced disease severity whereas the lipid content in clubs of LTP mutants seems to be unaffected. Additional studies indicate a role for some LTPs during salt stress conditions in roots of A. thaliana.

  5. Automated detection of exudates for diabetic retinopathy screening

    International Nuclear Information System (INIS)

    Automated image analysis is being widely sought to reduce the workload required for grading images resulting from diabetic retinopathy screening programmes. The recognition of exudates in retinal images is an important goal for automated analysis since these are one of the indicators that the disease has progressed to a stage requiring referral to an ophthalmologist. Candidate exudates were detected using a multi-scale morphological process. Based on local properties, the likelihoods of a candidate being a member of classes exudate, drusen or background were determined. This leads to a likelihood of the image containing exudates which can be thresholded to create a binary decision. Compared to a clinical reference standard, images containing exudates were detected with sensitivity 95.0% and specificity 84.6% in a test set of 13 219 images of which 300 contained exudates. Depending on requirements, this method could form part of an automated system to detect images showing either any diabetic retinopathy or referable diabetic retinopathy

  6. Automated detection of exudates for diabetic retinopathy screening

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Alan D [Biomedical Physics, University of Aberdeen, Aberdeen, AB25 2ZD (United Kingdom); Philip, Sam [Diabetes Retinal Screening Service, David Anderson Building, Foresterhill Road, Aberdeen, AB25 2ZP (United Kingdom); Goatman, Keith A [Biomedical Physics, University of Aberdeen, Aberdeen, AB25 2ZD (United Kingdom); Williams, Graeme J [Diabetes Retinal Screening Service, David Anderson Building, Foresterhill Road, Aberdeen, AB25 2ZP (United Kingdom); Olson, John A [Diabetes Retinal Screening Service, David Anderson Building, Foresterhill Road, Aberdeen, AB25 2ZP (United Kingdom); Sharp, Peter F [Biomedical Physics, University of Aberdeen, Aberdeen, AB25 2ZD (United Kingdom)

    2007-12-21

    Automated image analysis is being widely sought to reduce the workload required for grading images resulting from diabetic retinopathy screening programmes. The recognition of exudates in retinal images is an important goal for automated analysis since these are one of the indicators that the disease has progressed to a stage requiring referral to an ophthalmologist. Candidate exudates were detected using a multi-scale morphological process. Based on local properties, the likelihoods of a candidate being a member of classes exudate, drusen or background were determined. This leads to a likelihood of the image containing exudates which can be thresholded to create a binary decision. Compared to a clinical reference standard, images containing exudates were detected with sensitivity 95.0% and specificity 84.6% in a test set of 13 219 images of which 300 contained exudates. Depending on requirements, this method could form part of an automated system to detect images showing either any diabetic retinopathy or referable diabetic retinopathy.

  7. Automatic Detection of Retinal Exudates using a Support Vector Machine

    OpenAIRE

    Nualsawat HIRANSAKOLWONG; Ekkarat POTHIRUK; Kittipol WISAENG

    2013-01-01

    Retinal exudates are among the preliminary signs of diabetic retinopathy, a major cause of vision loss in diabetic patients. Correct and efficient screening of exudates is very expensive in professional time and may cause human error. Nowadays, the digital retinal image is frequently used to follow-up and diagnoses eye diseases. Therefore, the retinal image is crucial and essential for experts to detect exudates. Unfortunately, it is a normal situation that retinal images in Thailand are poor...

  8. THE CLINICAL APPLICATIONS FOR AUTOMATIC DETECTION OF EXUDATES

    OpenAIRE

    K. Wisaeng; N. Hiransakolwong; E. Pothiruk

    2014-01-01

    Nowadays, the retinal imaging technology has been widely used for segmenting and detecting the exudates in diabetic retinopathy patients. Unfortunately, the retinal images in Thailand are poor-quality images. Therefore, detecting of exudates in a large number by screening programs, are very expensive in professional time and may cause human error. In this study, the clinical applications for detection of exudates from the poor quality retinal image are presented. An application incorporating ...

  9. Altered acetylcholinesterase levels in the spinal cord anterior horn and dorsal root ganglion following sciatic nerve ischemia

    Institute of Scientific and Technical Information of China (English)

    Zhenjun Yang; Pei Wang; Songhe Yang; Jingfeng Xue

    2009-01-01

    BACKGROUND: Peripheral nerve ischemia has been shown to result in ischemic fiber degeneration and axoplasmic transport disturbance. However, the effect on acetylcholinesterase (AChE) expression in relevant cells following sciatic nerve ischemia remains unclear. OBJECTIVE: To observe AChE concentration changes following peripheral nerve ischemia. DESIGN, TIME AND SETTING: The present comparative observation, neuroanatomical experiment was performed at the Central Laboratory Animal of Chengde Medical College between 2006 and 2007. MATERIALS: A total of 20 healthy, adult, Wistar rats were randomized into two groups (n = 10): 8-day ischemia and 14-day ischemia. METHODS: Ischemia injury was induced in the unilateral sciatic nerve (experimental side) through ligation of the common iliac artery. The contralateral side received no intervention, and served as the control side. Rats in the 8-day ischemia and 14-day ischemia groups were allowed to survive for 8 and 14 days, respectively. MAIN OUTCOME MEASURES: The L5 lumbar spinal cord and the L5 dorsal root ganglion were removed from both sides and sectioned utilizing a Leica vibrating slicer. AChE cellular expression was detected using Karnovsky-Root, and the number of AChE-positive cells and average gray value were analyzed using a MiVnt image analysis system. RESULTS: In the 8-day ischemia group, AChE-positive cell numbers were significantly less in the dorsal root ganglion and spinal cord anterior horn of the experimental side, but the average gray value was significantly greater, compared with the control side (P < 0.05). These changes were more significant in the 14-day ischemia group than in the 8-day ischemia group (P < 0.01). CONCLUSION: Peripheral nerve ischemia leads to decreased AChE expression in the associated cells in a time-dependent manner.

  10. Altered dendritic arborization of amygdala neurons in young adult rats orally intubated with Clitorea ternatea aqueous root extract.

    Science.gov (United States)

    Rai, Kiranmai S; Murthy, K Dilip; Rao, Muddanna S; Karanth, K Sudhakar

    2005-07-01

    Young adult (60 day old) Wistar rats of either sex were orally intubated with 50 mg/kg body weight and 100 mg/kg body weight of aqueous root extract of Clitoria ternatea (CTR) for 30 days, along with age-matched saline controls. These rats were then subjected to passive avoidance tests and the results from these studies showed a significant increase in passive avoidance learning and retention. Subsequent to the passive avoidance tests, these rats were killed by decapitation. The amygdala was processed for Golgi staining and the stained neurons were traced using a camera lucida and analysed. The results showed a significant increase in dendritic intersections, branching points and dendritic processes arising from the soma of amygdaloid neurons in CTR treated rats especially in the 100 mg/kg group of rats, compared with age-matched saline controls. This improved dendritic arborization of amygdaloid neurons correlates with the increased passive avoidance learning and memory in the CTR treated rats as reported earlier. The results suggest that Clitoria ternatea aqueous root extract enhances memory by increasing the functional growth of neurons of the amygdala. PMID:16161034

  11. Biosynthesis of Lipid Resorcinols and Benzoquinones in Isolated Secretory Plant Root Hairs

    Science.gov (United States)

    The primary functions of root hairs are to increase the root surface area and to aid plants in water and nutrient uptake. However, some root hairs also have secretory functions and exude bioactive secondary metabolites. Sorghum bicolor root hairs release a substantial amount of the lipid benzoquin...

  12. Disappearance of diabetic macular hard exudates after hemodialysis introduction.

    Directory of Open Access Journals (Sweden)

    Matsuo,Toshihiko

    2006-06-01

    Full Text Available

    We report herein the disappearance of macular hard exudates after the introduction of hemodialysis in diabetic patients. A 62-year-old woman and a 52-year-old man with diabetes mellitus showed hard exudates in the macula of the left eyes. Both patients had previously undergone panretinal photocoagulation in both eyes. During the follow-up, hemodialysis was introduced for deteriorating chronic renal failure caused by diabetic nephropathy. Half a year later, macular hard exudates in the left eyes disappeared dramatically in both patients, but the visual acuity remained the same. No additional laser treatment was done during the observation period. Hemodialysis is considered to have accelerated the resolution of macular hard exudates in both patients. The deposition of macular hard exudates in diabetic patients is due in part to concurrent poor renal function.

  13. Exudation of organic acids by Lupinus albus and Lupinus angustifolius as affected by phosphorus supply

    Science.gov (United States)

    Hentschel, Werner; Wiche, Oliver

    2016-04-01

    In phytomining and phytoremediation research mixed cultures of bioenergy crops with legumes hold promise to enhance availability of trace metals and metalloids in the soil plant system. This is due to the ability of certain legumes to mobilize trace elements during acquisition of nutrients making these elements available for co-cultured species. The legumes achieve this element mobilization by exudating carboxylates and enzymes as well as by lowering the pH value in the rhizosphere. The aim of our research was to determine characteristics and differences in the exudation of Lupinus albus and Lupinus angustifolius regarding to quantitative as to qualitative aspects. Especially the affection by phosphorus (P) supply was a point of interest. Thus we conducted laboratory batch experiments, wherein the plants were grown over four weeks under controlled light, moisture and nutritional conditions on sand as substrate. Half of the plants were supplied with 12 mg P per kg substrate, the other half were cultivated under a total lack of P. After cultivation the plants were transferred from the cultivation substrate into a 0,05 mmolṡL‑1 CaCl2 solution. After two hours the plants were removed, moist and dry mass off shoots and roots were measured together with the root length (Tennants' method). Concentrations of exudated carboxylates in the CaCl2 solution were determined via IC (column: Metrosept OrganicAcids, eluent 0.5 molṡL‑1 H2SO4 + 15% acetone, pH=3; 0.5 mLṡmin‑1). As a result four different organic acids were identified (citric acid, fumaric acid, tartaric acid, malic acid) in concentration ranges of 0.15 mgṡL‑1 (fumaric acid) to 9.21 mgṡL‑1 (citric acid). Lupinus angustifolius showed a higher exudation rate (in nmol per cm root length per hour) than Lupinus albus in the presence of phosphorus (e.g. regarding citric acid: 1.99 vs 0.64 nmolṡ(gṡh)‑1). However, as the root complexity and length of L. albus were far higher than of L. angustifolius

  14. Controlled release of 6-aminonicotinamide from aligned, electrospun fibers alters astrocyte metabolism and dorsal root ganglia neurite outgrowth

    Science.gov (United States)

    Schaub, Nicholas J.; Gilbert, Ryan J.

    2011-08-01

    Following central nervous system (CNS) injury, activated astrocytes form a glial scar that inhibits the migration of axons ultimately leading to regeneration failure. Biomaterials developed for CNS repair can provide local delivery of therapeutics and/or guidance mechanisms to encourage cell migration into damaged regions of the brain or spinal cord. Electrospun fibers are a promising type of biomaterial for CNS injury since these fibers can direct cellular and axonal migration while slowly delivering therapy to the injury site. In this study, it was hypothesized that inclusion of an anti-metabolite, 6-aminonicotinamide (6AN), within poly-l-lactic acid electrospun fibers could attenuate astrocyte metabolic activity while still directing axonal outgrowth. Electrospinning parameters were varied to produce highly aligned electrospun fibers that contained 10% or 20% (w/w) 6AN. 6AN release from the fiber substrates occurred continuously over 2 weeks. Astrocytes placed onto drug-releasing fibers were less active than those cultured on scaffolds without 6AN. Dorsal root ganglia placed onto control and drug-releasing scaffolds were able to direct neurites along the aligned fibers. However, neurite outgrowth was stunted by fibers that contained 20% 6AN. These results show that 6AN release from aligned, electrospun fibers can decrease astrocyte activity while still directing axonal outgrowth.

  15. Arsenic Induced Phytate Exudation, and Promoted FeAsO4 Dissolution and Plant Growth in As-Hyperaccumulator Pteris vittata.

    Science.gov (United States)

    Liu, Xue; Fu, Jing-Wei; Guan, Dong-Xing; Cao, Yue; Luo, Jun; Rathinasabapathi, Bala; Chen, Yanshan; Ma, Lena Q

    2016-09-01

    Arsenic hyperaccumulator Pteris vittata (PV) is efficient in taking up As and nutrients from As-contaminated soils. We evaluated the mechanisms used by PV to mobilize As and Fe by examining the impacts of As and root exudates on FeAsO4 solubilization, and As and Fe uptake in four plants: As-hyperaccumulators PV and Pteris multifida (PM), nonhyperaccumulator Pteris ensiformis (PE), and angiosperm plant tomato (Solanum lycopersicum). Phytate and oxalate were dominant in fern plants (>93%), which were 50-83, 15-42, and 0-32 mg kg(-1) phytate and 10-15, 7-26, and 4-12 mg kg(-1) oxalate for PV, PM, and PE respectively, with higher As inducing greater phytate exudation and no phytate being detected in tomato exudates. PV treated with phytate+FeAsO4 had higher As and Fe contents and larger biomass than phytate or FeAsO4 treatment, which were 340 vs 20 and 130 mg kg(-1) As in the fronds and 7900 vs 1600 and 4100 mg kg(-1) Fe in the roots. We hypothesized that As-induced phytate exudation helped PV to take up Fe and As from insoluble FeAsO4 and promoted PV growth. Our study suggests that phytate exudation may be special to fern plants, which may play an important role in enhancing As and nutrient uptake by plants, thereby increasing their efficiency in phytoremediation of As-contaminated soils. PMID:27483027

  16. Microbial processes associated with roots of bulbous rush coated with iron plaques

    Energy Technology Data Exchange (ETDEWEB)

    Kusel, K.; Chabbi, A.; Trinkwalter, T. [University of Bayreuth, Bayreuth (Germany). BITOEK

    2003-11-01

    The objectives of this work were to enumerate the microbes involved in the turnover of iron and organic root exudates in the rhizoplane, to investigate the effect of oxygen and pH on the utilization of these exudates by the rhizobacteria, and to study the ability of the root-colonizing microbiota to reduce sulfate. Enumeration studies done at pH 3 demonstrated that 10{sup 6} Fe(III) reducers and 10{sup 7} Fe(II) oxidizers g (fresh wt root){sup -1} were associated with Juncus roots. When roots were incubated in goethite-containing medium without and with supplemental glucose, Fe(II) was formed at rates approximating 1.1 mmol g (fresh wt root) {sup -1} d{sup -1} and 3.6 mmol g (fresh wt root){sup -1} d{sup -1} under anoxic conditions, respectively. These results suggest that a rapid microbially mediated cycling of iron occurs in the rhizosphere of Juncus roots under changing redox conditions. Most-probable-number estimates of aerobes and anaerobes capable of consuming root exudates at pH 3 were similar in the rhizosphere sediment and in Juncus roots, but numbers of aerobes were significantly higher than those of anaerobes. At pH 3, supplemental organic exudates were primarily subject to aerobic oxidation to CO{sub 2} and not subject to fermentation. However, at pH 4.5, root exudates were also rapidly utilized under anoxic conditions. Root-associated sulfate reduction was not observed at pH 3 to 4.5 but was observed at pH 4.9. The pH increased during all root-incubation studies both under oxic and anoxic conditions. Thus, as result of the microbial turnover of organic root exudates, pH and CO{sub 2} levels might be elevated at the root surface and favor Juncus plants to colonize acidic habitats.

  17. Developmental Alterations in Heart Biomechanics and Skeletal Muscle Function in Desmin Mutants Suggest an Early Pathological Root for Desminopathies

    Directory of Open Access Journals (Sweden)

    Caroline Ramspacher

    2015-06-01

    Full Text Available Desminopathies belong to a family of muscle disorders called myofibrillar myopathies that are caused by Desmin mutations and lead to protein aggregates in muscle fibers. To date, the initial pathological steps of desminopathies and the impact of desmin aggregates in the genesis of the disease are unclear. Using live, high-resolution microscopy, we show that Desmin loss of function and Desmin aggregates promote skeletal muscle defects and alter heart biomechanics. In addition, we show that the calcium dynamics associated with heart contraction are impaired and are associated with sarcoplasmic reticulum dilatation as well as abnormal subcellular distribution of Ryanodine receptors. Our results demonstrate that desminopathies are associated with perturbed excitation-contraction coupling machinery and that aggregates are more detrimental than Desmin loss of function. Additionally, we show that pharmacological inhibition of aggregate formation and Desmin knockdown revert these phenotypes. Our data suggest alternative therapeutic approaches and further our understanding of the molecular determinants modulating Desmin aggregate formation.

  18. 水稻氮高效基因型根系分泌物中有机酸和氨基酸的变化特征%Characteristics of organic acid and amino acid in root exudates of rice genotype with high nitrogen efficiency

    Institute of Scientific and Technical Information of China (English)

    戢林; 李廷轩; 张锡洲; 余海英

    2012-01-01

    采用溶液培养试验,研究水稻氮高效基因型在不同供氮水平下,根系分泌物中有机酸和氨基酸种类及含量的变化情况,并探讨其与氮素利用效率之间的关系。结果表明: 1)水稻氮高效基因型氮积累量随着供氮水平的降低明显下降,而氮素利用效率显著提高; 在供氮水平为20 mg/L时,高效基因型具有较高的氮积累量,且氮素利用效率较低效基因型高42.9%(分蘖期)和21.4%(拔节期)。 2)草酸为高效基因型根系分泌的主要有机酸种类,其分泌量占有机酸总量的80%以上,其次是乙酸和柠檬酸; 有机酸分泌总量和草酸分泌量在分蘖期和拔节期随供氮水平的降低而降低,乙酸和柠檬酸分泌量在拔节期也呈相同趋势; 相同供氮水平下,高效基因型有机酸分泌总量均显著低于低效基因型,且在20 mg/L时差异明显。 3)丙氨酸为高效基因型根系分泌的主要氨基酸种类,其分泌量占氨基酸总量的50%以上,其次是丝氨酸、 谷氨酸、 天冬氨酸、 苯丙氨酸、 甘氨酸和苏氨酸,且氨基酸分泌总量和各组分氨基酸分泌量均随供氮水平的降低而降低; 在低氮水平(10 mg/L和20 mg/L)下,高效基因型氨基酸分泌总量均显著低于低效基因型。4)在分蘖期和拔节期,水稻根系分泌有机酸和氨基酸总量与氮素利用效率均呈显著或极显著负相关,有机酸分泌组分中的草酸和氨基酸分泌组分的天冬氨酸分泌量与氮素利用效率也呈显著或极显著负相关。以上结果表明,低氮条件下水稻氮高效基因型氮效率优势明显,高效基因型氮素利用效率高,有利于体内同化物质的合理分配。%Nitrogen plays important roles in promoting plant growth and development. The purpose of this study was to investigate how N nutrient affect the changes in the root exudates under different nitrogen levels and their

  19. Retinoid-like activity and teratogenic effects of cyanobacterial exudates.

    Science.gov (United States)

    Jonas, Adam; Buranova, Veronika; Scholz, Stefan; Fetter, Eva; Novakova, Katerina; Kohoutek, Jiri; Hilscherova, Klara

    2014-10-01

    Retinoic acids and their derivatives have been recently identified by chemical analyses in cyanobacteria and algae. Given the essential role of retinoids for vertebrate development this has raised concerns about a potential risk for vertebrates exposed to retinoids during cyanobacterial blooms. Our study focuses on extracellular compounds produced by phytoplankton cells (exudates). In order to address the capacity for the production of retinoids or compounds with retinoid-like activity we compared the exudates of ten cyanobacteria and algae using in vitro reporter gene assay. Exudates of three cyanobacterial species showed retinoid-like activity in the range of 269-2,265 ng retinoid equivalents (REQ)/L, while there was no detectable activity in exudates of the investigated algal species. The exudates of one green alga (Desmodesmus quadricaudus) and the two cyanobacterial species with greatest REQ levels, Microcystis aeruginosa and Cylindrospermopsis raciborskii, were selected for testing of the potential relation of retinoid-like activity to developmental toxicity in zebrafish embryos. The exudates of both cyanobacteria were indeed provoking diverse teratogenic effects (e.g. tail, spine and mouth deformation) and interference with growth in zebrafish embryos, while such effects were not observed for the alga. Fish embryos were also exposed to all-trans retinoic acid (ATRA) in a range equivalent to the REQ concentrations detected in exudates by in vitro bioassays. Both the phenotypes and effective concentrations of exudates corresponded to ATRA equivalents, supporting the hypothesis that the teratogenic effects of cyanobacterial exudates are likely to be associated with retinoid-like activity. The study documents that some cyanobacteria are able to produce and release retinoid-like compounds into the environment at concentrations equivalent to those causing teratogenicity in zebrafish. Hence, the characterization of retinoid-like and teratogenic potency should be

  20. Staphylococcus hyicus virulence in relation to exudative epidermitis in pigs

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar; Andresen, Lars Ole; Bille-Hansen, Vivi

    1993-01-01

    Staphylococcus hyicus strains with different phage types, plasmid profiles, and antibiotic resistance patterns were isolated from piglets with exudative epidermitis. The strains could be divided into virulent strains, producing exudative epidermitis, and avirulent strains, producing no dermal...... concluded that crusting reaction of piglet skin is a suitable indicator of virulence in S. hyicus in relation to exudative epidermitis, and that virulent strains produce a 30 kDa protein, absent in concentrated culture supernatants from avirulent strains. This 30 kDa protein might be an exfoliative toxin....

  1. LMWOA (low molecular weight organic acid) exudation by salt marsh plants: Natural variation and response to Cu contamination

    Science.gov (United States)

    Mucha, Ana P.; Almeida, C. Marisa R.; Bordalo, Adriano A.; Vasconcelos, M. Teresa S. D.

    2010-06-01

    This work aimed to evaluate, in vitro, the capability of roots of two salt marsh plants to release low molecular weight organic acids (LMWOAs) and to ascertain whether Cu contamination would stimulate or not organic acids exudation. The sea rush Juncus maritimus and the sea-club rush Scirpus maritimus, both from the lower Douro river estuary (NW Portugal), were used. Plants were collected seasonally, four times a year in 2004, during low tide. After sampling, plant roots were washed for removal of adherent particles and immersed for 2 h in a solution that matched salinity (3) and pH (7.5) of the pore water from the same location to obtain plant exudates. In one of the seasons, similar experiments were carried out but spiking the solution with different amounts of Cu in order to embrace the range between 0 and 1600 nM. In the final solutions as well as in sediment pore water LMWOAs were determined by high performance liquid chromatography. Plants were able to release, in a short period of time, relatively high amounts of LMWOAs (oxalate, citrate, malate, malonate, and succinate). In the sediment pore water oxalate, succinate and acetate were also detected. Therefore, plant roots probably contributed to the presence of some of these organic compounds in pore water. Exudation differed between the plant species and also showed some seasonally variation, particularly for S. maritimus. The release of oxalate by J. maritimus increased with Cu increase in the media. However, exudation of the other LMWOAs did not seem to be stimulated by Cu contamination in the media. This fact is compatible with the existence of alternative internal mechanisms for Cu detoxification, as denoted by the fact that in media contaminated with Cu both plant species accumulated relatively high amounts (29-83%) of the initially dissolved Cu. This study expands our knowledge on the contribution of globally dominant salt marsh plants to the release of LMWOAs into the environment.

  2. Associating rice root morphology and physiological traits with grain mineral concentrations of 24 varieties with extreme mineral compositions

    Science.gov (United States)

    The first step towards mineral accumulation in plant seeds is the absorption/uptake of minerals from the soil by roots. Root physiological activities, such as root respiration and metabolism, modify physical (soil temperature), chemical (soil pH, redox potential, root exudates, allelochemicals, and ...

  3. Reduced germination of Orobanche cumana seeds in the presence of Arbuscular Mycorrhizal fungi or their exudates.

    Directory of Open Access Journals (Sweden)

    Johann Louarn

    Full Text Available Broomrapes (Orobanche and Phelipanche spp are parasitic plants responsible for important crop losses, and efficient procedures to control these pests are scarce. Biological control is one of the possible strategies to tackle these pests. Arbuscular Mycorrhizal (AM fungi are widespread soil microorganisms that live symbiotically with the roots of most plant species, and they have already been tested on sorghum for their ability to reduce infestation by witchweeds, another kind of parasitic plants. In this work AM fungi were evaluated as potential biocontrol agents against Orobanche cumana, a broomrape species that specifically attacks sunflower. When inoculated simultaneously with O. cumana seeds, AM fungi could offer a moderate level of protection against the broomrape. Interestingly, this protection did not only rely on a reduced production of parasitic seed germination stimulants, as was proposed in previous studies. Rather, mycorrhizal root exudates had a negative impact on the germination of O. cumana induced by germination stimulants. A similar effect could be obtained with AM spore exudates, establishing the fungal origin of at least part of the active compounds. Together, our results demonstrate that AM fungi themselves can lead to a reduced rate of parasitic seed germination, in addition to possible effects mediated by the mycorrhizal plant. Combined with the other benefits of AM symbiosis, these effects make AM fungi an attractive option for biological control of O. cumana.

  4. Tumor Necrosis Factor-Alpha in Peripical Tissue Exudates of Teeth with Apical Periodontitis

    Directory of Open Access Journals (Sweden)

    Sonja Pezelj-Ribaric

    2007-01-01

    Full Text Available Aim. The aim of this study was to determine tumor necrosis factor-alpha (TNF-α levels in periapical exudates and to evaluate their relationship with radiological findings. Methodology. Periapical exudates were collected from root canals of 60 single-rooted teeth using absorbent paper points. TNF-α levels were determined by enzyme-linked immunosorbent assays. The samples were divided into three groups according to the periapical radiolucent area. Results. Nonparametric Kruskal-Wallis test revealed significant differences between TNF-α concentrations in control group (40, 57±28, 15 pg/mL and group with larger radiolucent areas (2365, 79±582, 95 pg/mL, as well as between control and canals with small radiolucent areas (507, 66±278, 97 (P<.05. Conclusions. The levels of TNF-α increase significantly in teeth with periapical pathosis, from smaller to bigger lesions. This research and its results have shown that objective analysis of the TNF-α levels enables establishment of a relationship between different concentrations of TNF-α and different radiological changes.

  5. Nitrate Protects Cucumber Plants Against Fusarium oxysporum by Regulating Citrate Exudation.

    Science.gov (United States)

    Wang, Min; Sun, Yuming; Gu, Zechen; Wang, Ruirui; Sun, Guomei; Zhu, Chen; Guo, Shiwei; Shen, Qirong

    2016-09-01

    Fusarium wilt causes severe yield losses in cash crops. Nitrogen plays a critical role in the management of plant disease; however, the regulating mechanism is poorly understood. Using biochemical, physiological, bioinformatic and transcriptome approaches, we analyzed how nitrogen forms regulate the interactions between cucumber plants and Fusarium oxysporum f. sp. cucumerinum (FOC). Nitrate significantly suppressed Fusarium wilt compared with ammonium in both pot and hydroponic experiments. Fewer FOC colonized the roots and stems under nitrate compared with ammonium supply. Cucumber grown with nitrate accumulated less fusaric acid (FA) after FOC infection and exhibited increased tolerance to chemical FA by decreasing FA absorption and transportation in shoots. A lower citrate concentration was observed in nitrate-grown cucumbers, which was associated with lower MATE (multidrug and toxin compound extrusion) family gene and citrate synthase (CS) gene expression, as well as lower CS activity. Citrate enhanced FOC spore germination and infection, and increased disease incidence and the FOC population in ammonium-treated plants. Our study provides evidence that nitrate protects cucumber plants against F. oxysporum by decreasing root citrate exudation and FOC infection. Citrate exudation is essential for regulating disease development of Fusarium wilt in cucumber plants. PMID:27481896

  6. Reduced germination of Orobanche cumana seeds in the presence of Arbuscular Mycorrhizal fungi or their exudates.

    Science.gov (United States)

    Louarn, Johann; Carbonne, Francis; Delavault, Philippe; Bécard, Guillaume; Rochange, Soizic

    2012-01-01

    Broomrapes (Orobanche and Phelipanche spp) are parasitic plants responsible for important crop losses, and efficient procedures to control these pests are scarce. Biological control is one of the possible strategies to tackle these pests. Arbuscular Mycorrhizal (AM) fungi are widespread soil microorganisms that live symbiotically with the roots of most plant species, and they have already been tested on sorghum for their ability to reduce infestation by witchweeds, another kind of parasitic plants. In this work AM fungi were evaluated as potential biocontrol agents against Orobanche cumana, a broomrape species that specifically attacks sunflower. When inoculated simultaneously with O. cumana seeds, AM fungi could offer a moderate level of protection against the broomrape. Interestingly, this protection did not only rely on a reduced production of parasitic seed germination stimulants, as was proposed in previous studies. Rather, mycorrhizal root exudates had a negative impact on the germination of O. cumana induced by germination stimulants. A similar effect could be obtained with AM spore exudates, establishing the fungal origin of at least part of the active compounds. Together, our results demonstrate that AM fungi themselves can lead to a reduced rate of parasitic seed germination, in addition to possible effects mediated by the mycorrhizal plant. Combined with the other benefits of AM symbiosis, these effects make AM fungi an attractive option for biological control of O. cumana. PMID:23145139

  7. Automatic Detection of Retinal Exudates using a Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Nualsawat HIRANSAKOLWONG

    2013-02-01

    Full Text Available Retinal exudates are among the preliminary signs of diabetic retinopathy, a major cause of vision loss in diabetic patients. Correct and efficient screening of exudates is very expensive in professional time and may cause human error. Nowadays, the digital retinal image is frequently used to follow-up and diagnoses eye diseases. Therefore, the retinal image is crucial and essential for experts to detect exudates. Unfortunately, it is a normal situation that retinal images in Thailand are poor quality images. In this paper, we present a series of experiments on feature selection and exudates classification using the support vector machine classifiers. The retinal images are segmented following key preprocessing steps, i.e., color normalization, contrast enhancement, noise removal and color space selection. On data sets of poor quality images, sensitivity, specificity and accuracy is 94.46%, 89.52% and 92.14%, respectively.

  8. Ubiquitous water-soluble molecules in aquatic plant exudates determine specific insect attraction.

    Directory of Open Access Journals (Sweden)

    Julien Sérandour

    Full Text Available Plants produce semio-chemicals that directly influence insect attraction and/or repulsion. Generally, this attraction is closely associated with herbivory and has been studied mainly under atmospheric conditions. On the other hand, the relationship between aquatic plants and insects has been little studied. To determine whether the roots of aquatic macrophytes release attractive chemical mixtures into the water, we studied the behaviour of mosquito larvae using olfactory experiments with root exudates. After testing the attraction on Culex and Aedes mosquito larvae, we chose to work with Coquillettidia species, which have a complex behaviour in nature and need to be attached to plant roots in order to obtain oxygen. This relationship is non-destructive and can be described as commensal behaviour. Commonly found compounds seemed to be involved in insect attraction since root exudates from different plants were all attractive. Moreover, chemical analysis allowed us to identify a certain number of commonly found, highly water-soluble, low-molecular-weight compounds, several of which (glycerol, uracil, thymine, uridine, thymidine were able to induce attraction when tested individually but at concentrations substantially higher than those found in nature. However, our principal findings demonstrated that these compounds appeared to act synergistically, since a mixture of these five compounds attracted larvae at natural concentrations (0.7 nM glycerol, <0.5 nM uracil, 0.6 nM thymine, 2.8 nM uridine, 86 nM thymidine, much lower than those found for each compound tested individually. These results provide strong evidence that a mixture of polyols (glycerol, pyrimidines (uracil, thymine, and nucleosides (uridine, thymidine functions as an efficient attractive signal in nature for Coquillettidia larvae. We therefore show for the first time, that such commonly found compounds may play an important role in plant-insect relationships in aquatic eco-systems.

  9. Physiological responses in roots of the grapevine rootstock 140 Ruggeri subjected to Fe deficiency and Fe-heme nutrition.

    Science.gov (United States)

    López-Rayo, Sandra; Di Foggia, Michele; Rodrigues Moreira, Erica; Donnini, Silvia; Bombai, Giuseppe; Filippini, Gianfranco; Pisi, Annamaria; Rombolà, Adamo D

    2015-11-01

    Iron (Fe)-heme containing fertilizers can effectively prevent Fe deficiency. This paper aims to investigate root physiological responses after a short period of Fe-heme nutrition and Fe deficiency under two pH conditions (with or without HEPES) in the Fe chlorosis-tolerant grapevine rootstock 140 Ruggeri. Organic acids in root exudates, Fe reduction capacity, both roots and root exudates contributions, together with other physiological parameters associated to plant Fe status were evaluated in plants grown in hydroponics. Analyses of root tips by SEM, and Raman and IR spectra of the precipitates of Fe-heme fertilizers were performed. The physiological responses adopted by the tolerant 140 Ruggeri to the application of Fe-heme indicated an increased Fe reduction capacity of the roots. This is the first report showing oxalic, tartaric, malic and ascorbic as major organic acids in Vitis spp. root exudates. Plants reacted to Fe deficiency condition exuding a higher amount of ascorbic acid in the rhizosphere. The presence of HEPES in the medium favoured the malic acid exudation. The lowest concentration of oxalic acid was found in exudates of plants subjected to Fe-heme and could be associated to a higher accumulation in their root tips visualized by SEM analysis. PMID:26276277

  10. Field performance of Solanum sisymbriifolium, a trap crop for potato cyst nematodes. II. Root characteristics

    NARCIS (Netherlands)

    Timmermans, B.G.H.; Vos, J.; Stomph, T.J.; Nieuwburg, van J.G.W.; Putten, van der P.E.L.

    2007-01-01

    Hatching of potato cyst nematodes is induced by root exudates of Solanaceae, such as Solanum sisymbriifolium, and is therefore related to root length distribution of this crop. A mathematical model was derived to relate the hatching potential to root length density (RLD). A series of field experimen

  11. Deficits in foot skin sensation are related to alterations in balance control in chronic low back patients experiencing clinical signs of lumbar nerve root impingement.

    Science.gov (United States)

    Frost, Lydia R; Bijman, Marc; Strzalkowski, Nicholas D J; Bent, Leah R; Brown, Stephen H M

    2015-05-01

    Chronic low back pain (LBP) patients with radiculopathy, or sciatica, experience pain, tingling or numbness radiating down their leg due to compression of the lumbar nerve root. The resulting reduction in somatosensory information from the foot sole may contribute to deficits in standing balance control. This work was designed to investigate the relationship between foot skin sensitivity and standing balance control in chronic LBP patients with associated radiculopathy. Patients (n=9) and matched healthy controls (n=9) were recruited to the study, and were tested for balance control in both quiet standing as well as during rapid arm raise perturbation trials on a force plate. Foot skin sensitivity was tested bilaterally for vibratory threshold (3, 40 and 250 Hz) and touch (monofilament) threshold. Results demonstrate that patients had reduced sensitivity to 250 Hz vibration in their affected compared to unaffected foot (at the great toe and heel), as well as compared to controls (at the great toe), but there were no differences with lower frequency vibratory testing or with monofilament testing. While there were no significant between-group differences in balance measures, moderate statistically significant correlations between 250 Hz sensitivity and quiet standing balance parameters were uncovered. Thus, patients demonstrate reduced high-frequency vibratory sensitivity at the foot sole, and correlations with quiet standing balance measures indicate a connection between these foot skin sensitivity deficits and alterations in balance control. Clinically, this identifies high frequency vibration testing as an important measure of skin sensitivity in patients with radiculopathy. PMID:25887249

  12. Unilateral, recurrent exudative retinal detachment in association with pansinusitis [

    Directory of Open Access Journals (Sweden)

    Osman Saatci, Ali

    2012-11-01

    Full Text Available [english] Aim: To report a patient with unilateral exudative retinal detachment due to pansinusitis.Methods: Case report.Results: A 65-year-old woman with a two-month history of blurred vision, red eye and lid swelling in her left eye was referred to us. Her best-corrected visual acuity was 20/20 in the right eye and 20/200 in the left. Conjunctival vessels were engorged in the OS. Funduscopy revealed a 360° exudative detachment in OS and computerized tomography (CT imaging revealed pansinusitis. Systemic antibiotic treatment was employed and exudative detachment regressed. However, exudative detachment remitted as soon as antibiotic treatment ceased. Finally she underwent sinus surgery and decompression of the orbita. Her visual acuity improved to 20/100 just two days after the surgery, stabilized at 20/30 and no further recurrences occured during the follow-up of 10 months.Conclusion: Since exudative retinal detachment usually accompanies systemic inflammatory or neoplastic diseases, systemic screening and collaboration with other disciplines are mandatory. To the best of our knowledge, this is the first report of a case that developed exudative retinal detachment due to pansinusitis and only recovered after decompression surgery.

  13. Soil sheaths, photosynthate distribution to roots, and rhizosphere water relations for Opuntia ficus-indica

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.; North, G.B.; Nobel, P.S. (Univ. of California, Los Angeles, CA (United States))

    1993-09-01

    Soil sheaths incorporating aggregated soil particles surround young roots of many species, but the effects of such sheaths on water movement between roots and the soil are largely unknown. The quantity and location of root exudates associated with soil sheath along the entire length of its young roots, except within 1.4 cm of the tip. The soil sheaths, which average 0.7 mm in thickness, were composed of soil particles and root hairs, both of which were covered with exuded mucilaginous material. As determined with a [sup 14]C pulse-labeling technique, 2% of newly fixed [sup 14]C-photosynthate was translocated into the roots at 3d, 6% at 9 d, and 8% at 15 d after labeling. The fraction of insoluble [sup 14]C in the roots increased twofold from 3 d to 15 d. Over the same time period, 6%-9% of the [sup 14]C translocated to the roots was exuded into the soil. The soluble [sup 14]C compounds exuded into the soil were greater in the 3-cm segment at the root tip than elsewhere along the root, whereas mucilage was exuded relatively uniformly along roots 15 cm in length. The volumetric efflux of water increase for both sheathed and unsheathed roots as the soil water potential decreased form -0.1 MPa to -1.0 MPa. The efflux rate was greater for unsheathed roots than for sheathed roots, which were more turgid and had a higher water potential, especially at lower soil water potentials. During drying, soil particles in the sheaths aggregate more tightly, making the sheaths less permeable to water and possibly creating air gaps. The soil sheaths of O. ficus-indica thus reduce water loss from the roots to a drying soil. 34 refs., 6 figs., 1 tab.

  14. Rhizosphere wettability decreases with root age: A problem or a strategy to increase water uptake of young roots?

    OpenAIRE

    Andrea eCarminati

    2013-01-01

    As plant roots take up water and the soil dries, water depletion is expected to occur in the vicinity of roots, the so called rhizosphere. However, recent experiments showed that the rhizosphere of lupines was wetter than the bulk soil during the drying period. Surprisingly, the rhizosphere remained temporarily dry after irrigation. Such water dynamics in the rhizosphere can be explained by the drying/wetting dynamics of mucilage exuded by roots. The capacity of mucilage to hold large volumes...

  15. Rhizosphere wettability decreases with root age: a problem or a strategy to increase water uptake of young roots?

    OpenAIRE

    Carminati, Andrea

    2013-01-01

    As plant roots take up water and the soil dries, water depletion is expected to occur in the vicinity of roots, the so called rhizosphere. However, recent experiments showed that the rhizosphere of lupines was wetter than the bulk soil during the drying period. Surprisingly, the rhizosphere remained temporarily dry after irrigation. Such water dynamics in the rhizosphere can be explained by the drying/wetting dynamics of mucilage exuded by roots. The capacity of mucilage to hold large volumes...

  16. Vegetable exudates as food for Callithrix spp. (Callitrichidae: exploratory patterns.

    Directory of Open Access Journals (Sweden)

    Talitha Mayumi Francisco

    Full Text Available Marmosets of the genus Callithrix are specialized in the consumption of tree exudates to obtain essential nutritional resource by boring holes into bark with teeth. However, marmoset preferences for particular tree species, location, type, and other suitable factors that aid in exudate acquisition need further research. In the current study, the intensity of exudate use from Anadenanthera peregrina var. peregrina trees by hybrid marmosets Callithrix spp. groups was studied in five forest fragments in Viçosa, in the state of Minas, Brazil. Thirty-nine A. peregrina var. peregrina trees were examined and 8,765 active and non-active holes were analyzed. The trunk of A. peregrina var. peregrina had a lower number of holes than the canopy: 11% were found on the trunk and 89% were found on the canopy. The upper canopy was the preferred area by Callithrix spp. for obtaining exudates. The intensity of tree exploitation by marmosets showed a moderate-to-weak correlation with diameter at breast height (DBH and total tree height. The overall results indicate that Anadenanthera peregrina var. peregrina provides food resources for hybrid marmosets (Callithrix spp. and these animals prefer to explore this resource on the apical parts of the plant, where the thickness, location, and age of the branches are the main features involved in the acquisition of exudates.

  17. THE CLINICAL APPLICATIONS FOR AUTOMATIC DETECTION OF EXUDATES

    Directory of Open Access Journals (Sweden)

    K. Wisaeng

    2014-01-01

    Full Text Available Nowadays, the retinal imaging technology has been widely used for segmenting and detecting the exudates in diabetic retinopathy patients. Unfortunately, the retinal images in Thailand are poor-quality images. Therefore, detecting of exudates in a large number by screening programs, are very expensive in professional time and may cause human error. In this study, the clinical applications for detection of exudates from the poor quality retinal image are presented. An application incorporating function, including retinal color normalization, contrast enhancement, noise removal, color space selection and removal of the optic disc, was also designed to standardize the workflow of retinal analysis. Afterward, detection of exudate based on optimal global thresholding and improved adaptive Otsu’s algorithm was applied. Two experiments were conducted to validate the detection performance with local databases and a publicly available DIARETDB1 database. The first experiment showed the average sensitivity, specificity and accuracy of 93.8, 95.3 and 94.9%, respectively. The cross validation results of the second experiment, 60% (53 of the retinal images were used for training and 40% (36 for testing, the sensitivity, specificity and accuracy are 84.2, 85.9 and 85.2%, respectively. This result indicates the proposed clinical application provides an effective tool in the screening of exudates.

  18. AUTOMATIC RETINA EXUDATES SEGMENTATION WITHOUT A MANUALLY LABELLED TRAINING SET

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy which can be assessed by detecting exudates (a type of bright lesion) in fundus images. In this work, two new methods for the detection of exudates are presented which do not use a supervised learning step and therefore do not require ground-truthed lesion training sets which are time consuming to create, difficult to obtain, and prone to human error. We introduce a new dataset of fundus images from various ethnic groups and levels of DME which we have made publicly available. We evaluate our algorithm with this dataset and compare our results with two recent exudate segmentation algorithms. In all of our tests, our algorithms perform better or comparable with an order of magnitude reduction in computational time.

  19. High-Density Lipoprotein Function in Exudative Age-Related Macular Degeneration

    Science.gov (United States)

    Pertl, Laura; Kern, Sabine; Weger, Martin; Hausberger, Silke; Trieb, Markus; Gasser-Steiner, Vanessa; Haas, Anton; Scharnagl, Hubert; Heinemann, Akos; Marsche, Gunther

    2016-01-01

    Purpose High-density lipoproteins (HDL) have long been implicated in the pathogenesis of age-related macular degeneration (AMD). However, conflicting results have been reported with regard to the associations of AMD with HDL-cholesterol levels. The present study is the first to assess HDL composition and metrics of HDL function in patients with exudative AMD and control patients. Methods Blood samples were collected from 29 patients with exudative AMD and 26 age-matched control patients. Major HDL associated apolipoproteins were determined in apoB-depleted serum by immunoturbidimetry or ELISA, HDL-associated lipids were quantified enzymatically. To get an integrated measure of HDL quantity and quality, we assessed several metrics of HDL function, including cholesterol efflux capacity, anti-oxidative and anti-inflammatory activities using apoB-depleted serum from study participants. Results In our study, we observed that the HDL associated acute phase protein serum amyloid A (SAA) was significantly increased in AMD patients (pAMD patients when compared with the control group. The ability of apoB-depleted serum to inhibit monocyte NF-κB expression was significantly improved in AMD patients (mean difference (MD) -5.6, pAMD subjects (MD -24.1, pAMD in this study, despite an increased content of HDL associated SAA in AMD patients. Unexpectedly, anti-inflammatory activity of apoB-depleted serum was even increased in our study. Our data suggest that the investigated parameters of serum HDL function showed no significant association with exudative AMD. However, we cannot exclude that alterations in locally produced HDL may be part of the AMD pathogenesis. PMID:27171197

  20. Hard Retinal exudates and visual loss due to papilledema

    Energy Technology Data Exchange (ETDEWEB)

    Rush, J.A.

    1982-02-01

    Bilateral papilledema developed in a patient with a cystic, grade 3 astrocytoma of the right frontal lobe. Despite successful neurosurgical treatment, /sup 60/Co radiotherapy, and oral corticosteroid therapy, progressive visual loss occurred. At examination one year later, visual activity was 20/200 and 20/70, and extensive lipid exudates in the peripapillary retina and central macula of each eye were noted. Retinal lipid exudates rarely complicate the course of surviving patients who had papilledema from intracranial tumor; physicians involved in the multispecialty care of such patients should be aware of the possible ocular residuals of persistent papilledema in an otherwise successfully treated patient.

  1. Long-Term Boron-Excess-Induced Alterations of Gene Profiles in Roots of Two Citrus Species Differing in Boron-Tolerance Revealed by cDNA-AFLP

    Science.gov (United States)

    Guo, Peng; Qi, Yi-Ping; Yang, Lin-Tong; Ye, Xin; Huang, Jing-Hao; Chen, Li-Song

    2016-01-01

    Boron (B) toxicity is observed in some citrus orchards in China. However, limited data are available on the molecular mechanisms of citrus B-toxicity and B-tolerance. Using cDNA-AFLP, we identified 20 up- and 52 down-regulated genes, and 44 up- and 66 down-regulated genes from excess B-treated Citrus sinensis and Citrus grandis roots, respectively, thereby demonstrating that gene expression profiles were more affected in the latter. In addition, phosphorus and total soluble protein concentrations were lowered only in excess B-treated C. grandis roots. Apparently, C. sinensis had higher B-tolerance than C. grandis. Our results suggested that the following several aspects were responsible for the difference in the B-tolerance between the two citrus species including: (a) B-excess induced Root Hair Defective 3 expression in C. sinensis roots, and repressed villin4 expression in C. grandis roots; accordingly, root growth was less inhibited by B-excess in the former; (b) antioxidant systems were impaired in excess B-treated C. grandis roots, hence accelerating root senescence; (c) genes related to Ca2+ signals were inhibited (induced) by B-excess in C. grandis (C. sinensis) roots. B-excess-responsive genes related to energy (i.e., alternative oxidase and cytochrome P450), lipid (i.e., Glycerol-3-phosphate acyltransferase 9 and citrus dioxygenase), and nucleic acid (i.e., HDA19, histone 4, and ribonucleotide reductase RNR1 like protein) metabolisms also possibly accounted for the difference in the B-tolerance between the two citrus species. These data increased our understanding of the mechanisms on citrus B-toxicity and B-tolerance at transcriptional level. PMID:27446128

  2. A stable-isotope mass spectrometry-based metabolic footprinting approach to analyze exudates from phytoplankton

    DEFF Research Database (Denmark)

    Weber, Ralf J. M.; Selander, Erik; Sommer, Ulf;

    2013-01-01

    Phytoplankton exudates play an important role in pelagic ecology and biogeochemical cycles of elements. Exuded compounds fuel the microbial food web and often encompass bioactive secondary metabolites like sex pheromones, allelochemicals, antibiotics, or feeding attractants that mediate biologica...

  3. Changos in phenolic contents of sheshum leaf exudates in response to infection with Phyllactinia dalbergiae

    OpenAIRE

    Sunita Bakshi; Chauhan, R. K.

    2014-01-01

    An increase in phenolic contents of leaf exudates was found after infection with Phyllactinia dalbergiae, but phenolic content decreased as the disease progressed. Healthy leaf exudates show a gradually decline in phenolic contents as the leaves mature.

  4. Adsorption and absorption of polycyclic aromatic hydrocarbons to rice roots

    International Nuclear Information System (INIS)

    Rice roots and surrounding air, soil and water samples were collected for polycyclic aromatic hydrocarbon (PAH) analysis. The rice roots were separated into lateral roots and nodal roots, and the PAH concentration in the former was found to be higher than that in the latter. In addition, root physiological characteristics including root biotic mass, root lipid content and specific surface area are also discussed. When normalizing the total, adsorption and absorption PAH fractions on a dry root weight basis to root biomass, root lipid, and surface area bases respectively, the differences between PAHs in the two types of roots diminished by 2 to 3 times on average. Results from sequential extraction indicated that PAHs were more easily absorbed by interior rice roots than adsorbed on the surface. In addition, more than 60% of total PAHs accumulated in root tissue for both lateral and nodal roots. However, the results were highly related to the solvent used, extraction time and methodology. Correlation analysis between bioconcentration factors (root over environment) and K OA, K OW showed water to be more significant for PAH adsorption in rice roots than other environmental media. - A sequential extraction method was applied to divide the PAHs accumulated on rice roots into PAHs in root exudates, PAHs adsorbed on root surfaces, and PAHs absorbed in root tissue

  5. Exudative epidermitis in pigs caused by toxigenic Staphylococcus chromogenes

    DEFF Research Database (Denmark)

    Andresen, Lars Ole; Ahrens, Peter; Daugaard, Lise;

    2005-01-01

    Staphylococcus chromogenes is closely related to Staphylococcus hyicus, which is recognised as the causative agent of exudative epidermitis (EE) in pigs. S. chromogenes is part of the normal skin flora of pigs, cattle and poultry and has so far been considered non-pathogenic to pigs. A strain of S...

  6. Stellate nonhereditary idiopathic foveomacular retinoschisis concomitant to exudative maculopathies.

    Science.gov (United States)

    Casalino, G; Upendran, M; Bandello, F; Chakravarthy, U

    2016-05-01

    PurposeTo report the clinical course of patients presenting with stellate nonhereditary idiopathic foveomacular retinoschisis (SNIFR) concomitant with exudative maculopathies.MethodsRetrospective case series. Multimodal imaging findings, including spectral-domain optical coherence tomography (SD-OCT) were reviewed. Genetic testing for the RS1 gene was performed in one patient.ResultsWe identified two female patients who fit the definition of SNIFR and presented with concomitant neovascular age-related macular degeneration (n-AMD). In both the patients, SD-OCT showed exudative macular features and splitting (bilateral in patient 1, unilateral in patient 2) of the outer plexiform layer (OPL) in the macula with no other evidence of hereditary or an acquired predisposing condition. Genetic testing excluded mutation of RS1 gene in patient 1. The fundi of both the patients showed characteristic signs of active choroidal neovascularization (CNV) and following anti-VEGF treatment, visual acuity improved and CNV-related exudative changes resolved. However, the split along the OPL remained unaltered.ConclusionsSNIFR may be associated with n-AMD. It is important to recognise the presence of retinoschisis when there is other exudative pathology as the former may be misinterpreted as intraretinal fluid, prompting unnecessary treatment. PMID:26915743

  7. Alteration of cell-wall porosity is involved in osmotic stress-induced enhancement of aluminium resistance in common bean (Phaseolus vulgaris L.).

    Science.gov (United States)

    Yang, Zhong-Bao; Eticha, Dejene; Rao, Idupulapati Madhusudana; Horst, Walter Johannes

    2010-07-01

    Aluminium (Al) toxicity and drought are the two major abiotic stress factors limiting common bean production in the tropics. Using hydroponics, the short-term effects of combined Al toxicity and drought stress on root growth and Al uptake into the root apex were investigated. In the presence of Al stress, PEG 6000 (polyethylene glycol)-induced osmotic (drought) stress led to the amelioration of Al-induced inhibition of root elongation in the Al-sensitive genotype VAX 1. PEG 6000 (> PEG 1000) treatment greatly decreased Al accumulation in the 1 cm root apices even when the roots were physically separated from the PEG solution using dialysis membrane tubes. Upon removal of PEG from the treatment solution, the root tips recovered from osmotic stress and the Al accumulation capacity was quickly restored. The PEG-induced reduction of Al accumulation was not due to a lower phytotoxic Al concentration in the treatment solution, reduced negativity of the root apoplast, or to enhanced citrate exudation. Also cell-wall (CW) material isolated from PEG-treated roots showed a low Al-binding capacity which, however, was restored after destroying the physical structure of the CW. The comparison of the Al(3+), La(3+), Sr(2+), and Rb(+) binding capacity of the intact root tips and the isolated CW revealed the specificity of the PEG 6000 effect for Al. This could be due to the higher hydrated ionic radius of Al(3+) compared with other cations (Al(3+) > La(3+) > Sr(2+) > Rb(+)). In conclusion, the results provide circumstantial evidence that the osmotic stress-inhibited Al accumulation in root apices and thus reduced Al-induced inhibition of root elongation in the Al-sensitive genotype VAX 1 is related to the alteration of CW porosity resulting from PEG 6000-induced dehydration of the root apoplast. PMID:20511277

  8. A mathematical model for investigating the effect of cluster roots on plant nutrient uptake

    KAUST Repository

    Zygalakis, K. C.

    2012-04-01

    Cluster roots are thought to play an important role in mediating nutrient uptake by plants. In this paper we develop a mathematical model for the transport and uptake of phosphate by a single root. Phosphate is assumed to diffuse in the soil fluid phase and can also solubilised due to citrate exudation. Using multiple scale homogenisation techniques we derive an effective model that accounts for the cumulative effect of citrate exudation and phosphate uptake by cluster roots whilst still retaining all the necessary information about the microscale geometry and effects. © 2012 EDP Sciences and Springer.

  9. The Nitrification Inhibitor Methyl 3-(4-Hydroxyphenyl)Propionate Modulates Root Development by Interfering with Auxin Signaling via the NO/ROS Pathway.

    Science.gov (United States)

    Liu, Yangyang; Wang, Ruling; Zhang, Ping; Chen, Qi; Luo, Qiong; Zhu, Yiyong; Xu, Jin

    2016-07-01

    Methyl 3-(4-hydroxyphenyl)propionate (MHPP) is a root exudate that functions as a nitrification inhibitor and as a modulator of the root system architecture (RSA) by inhibiting primary root (PR) elongation and promoting lateral root formation. However, the mechanism underlying MHPP-mediated modulation of the RSA remains unclear. Here, we report that MHPP inhibits PR elongation in Arabidopsis (Arabidopsis thaliana) by elevating the levels of auxin expression and signaling. MHPP induces an increase in auxin levels by up-regulating auxin biosynthesis, altering the expression of auxin carriers, and promoting the degradation of the auxin/indole-3-acetic acid family of transcriptional repressors. We found that MHPP-induced nitric oxide (NO) production promoted reactive oxygen species (ROS) accumulation in root tips. Suppressing the accumulation of NO or ROS alleviated the inhibitory effect of MHPP on PR elongation by weakening auxin responses and perception and by affecting meristematic cell division potential. Genetic analysis supported the phenotype described above. Taken together, our results indicate that MHPP modulates RSA remodeling via the NO/ROS-mediated auxin response pathway in Arabidopsis. Our study also revealed that MHPP significantly induced the accumulation of glucosinolates in roots, suggesting the diverse functions of MHPP in modulating plant growth, development, and stress tolerance in plants. PMID:27217493

  10. Phytotoxic compounds from roots of Centaurea diffusa Lam.

    OpenAIRE

    Quintana, Naira; El Kassis, Elie G; Stermitz, Frank R.; Vivanco, Jorge M.

    2009-01-01

    An extract of roots of Centaurea diffusa (diffuse knapweed) yielded caryophyllene oxide and linoleic acid which were shown to be phytotoxic. Also isolated were germacrene B, a previously-known phytotoxin as well as the inactive polyene aplotaxene. A combination of these compounds, if transferred to the soil, could be one factor in the invasive behavior of this weed. Contrary to a literature report, 8-hydroxyquinoline was not detected in root exudates of in vitro grown C. diffusa nor could it ...

  11. Root canal medicaments.

    Science.gov (United States)

    Kawashima, Nobuyuki; Wadachi, Reiko; Suda, Hideaki; Yeng, Thai; Parashos, Peter

    2009-02-01

    The ultimate goals of endodontic treatment are complete removal of bacteria, their byproducts and pulpal remnants from infected root canals and the complete seal of disinfected root canals. Intracanal medicaments have been thought an essential step in killing the bacteria in root canals; however, in modern endodontics, shaping and cleaning may be assuming greater importance than intracanal medicaments as a means of disinfecting root canals. Until recently, formocresol and its relatives were frequently used as intracanal medicaments, but it was pointed out that such bactericidal chemicals dressed in the canal distributed to the whole body from the root apex and so might induce various harmful effects including allergies. Furthermore, as these medicaments are potent carcinogenic agents, there is no indication for these chemicals in modern endodontic treatment. Today, biocompatibility and stability are essential properties for intracanal medicaments. The more modern meaning of intracanal dressing is for a blockade against coronal leakage from the gap between filling materials and cavity wall. Calcium hydroxide has been determined as suitable for use as an intracanal medicament as it is stable for long periods, harmless to the body, and bactericidal in a limited area. It also induces hard tissue formation and is effective for stopping inflammatory exudates. Single-visit endodontics, where intracanal medicaments are not used, is generally not now contraindicated and various reports have shown that the clinical outcomes between single- and multiple- visit endodontics are similar. There is no reason to counsel against single-visit endodontics: however, if multiple-visit endodontics is chosen, calcium hydroxide is recommended to be used as an intracanal medicament. PMID:19323305

  12. Cytokinin-Deficient Transgenic Arabidopsis Plants Show Multiple Developmental Alterations Indicating Opposite Functions of Cytokinins in the Regulation of Shoot and Root Meristem Activity

    Czech Academy of Sciences Publication Activity Database

    Werner, T.; Motyka, Václav; Laucou, V.; Smets, R.; Onckelen, H. V.; Schmülling, T.

    2003-01-01

    Roč. 15, č. 11 (2003), s. 2532-2550. ISSN 1040-4651 R&D Projects: GA AV ČR IAA6038002 Institutional research plan: CEZ:AV0Z5038910 Keywords : Transgenic Arabidopsis Plants * Cytokinins * Root Meristem Activity Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 10.679, year: 2003

  13. Bacteria with Phosphate Solubilizing Capacity Alter Mycorrhizal Fungal Growth Both Inside and Outside the Root and in the Presence of Native Microbial Communities

    Science.gov (United States)

    Lara, Lidia Susana; Rodriguez, Alia; Uribe-Vélez, Daniel; Sanders, Ian R.

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing Pseudomonas bacteria (PSB) could potentially interact synergistically because PSB solubilize phosphate into a form that AMF can absorb and transport to the plant. However, very little is known about the interactions between these two groups of microorganisms and how they influence the growth of each other. We tested whether different strains of bacteria, that have the capacity to solubilize phosphate, are able to grow along AMF hyphae and differentially influence the growth of AMF both outside the roots of carrot in in vitro conditions and inside the roots of potato in the presence of a microbial community. We found strong effects of AMF on the growth of the different bacterial strains. Different bacterial strains also had very strong effects on the growth of AMF extraradical hyphae outside the roots of carrot and on colonization of potato roots by AMF. The differential effects on colonization occurred in the presence of a microbial community. Our results show that these two important groups of rhizosphere microorganisms indeed interact with each other. Such interactions could potentially lead to synergistic effects between the two groups but this could depend on whether the bacteria truly solubilize phosphate in the rhizosphere in the presence of microbial communities. PMID:27253975

  14. Bacillus simplex—A Little Known PGPB with Anti-Fungal Activity—Alters Pea Legume Root Architecture and Nodule Morphology When Coinoculated with Rhizobium leguminosarum bv. viciae

    Directory of Open Access Journals (Sweden)

    Ann M. Hirsch

    2013-09-01

    Full Text Available Two strains, 30N-5 and 30VD-1, identified as Bacillus simplex and B. subtilis, were isolated from the rhizospheres of two different plants, a Podocarpus and a palm, respectively, growing in the University of California, Los Angeles (UCLA Mildred E. Mathias Botanical Garden. B. subtilis is a well-known plant-growth promoting bacterial species, but B. simplex is not. B. simplex 30N-5 was initially isolated on a nitrogen-free medium, but no evidence for nitrogen fixation was found. Nevertheless, pea plants inoculated with B. simplex showed a change in root architecture due to the emergence of more lateral roots. When Pisum sativum carrying a DR5::GUSA construct, an indicator for auxin response, was inoculated with either B. simplex 30N-5 or its symbiont Rhizobium leguminosarum bv. viciae 128C53, GUS expression in the roots was increased over the uninoculated controls. Moreover, when pea roots were coinoculated with either B. simplex 30N-5 or B. subtilis 30VD-1 and R. leguminosarum bv. viciae 128C53, the nodules were larger, clustered, and developed more highly branched vascular bundles. Besides producing siderophores and solubilizing phosphate, the two Bacillus spp., especially strain 30VD-1, exhibited anti-fungal activity towards Fusarium. Our data show that combining nodulating, nitrogen-fixing rhizobia with growth-promoting bacteria enhances plant development and strongly supports a coinoculation strategy to improve nitrogen fixation, increase biomass, and establish greater resistance to fungal disease.

  15. Chemical signatures of fossilized resins and recent plant exudates.

    Science.gov (United States)

    Lambert, Joseph B; Santiago-Blay, Jorge A; Anderson, Ken B

    2008-01-01

    Amber is one of the few gemstones based on an organic structure. Found over most of the world, it is the fossil form of sticky plant exudates called resins. Investigation of amber by modern analytical techniques provides structural information and insight into the identity of the ancient plants that produced the source resin. Mass spectrometric analysis of materials separated by gas chromatography has identified specific compounds that are the basis of a reliable classification of the different types of amber. NMR spectroscopy of bulk, solid amber provides a complementary classification. NMR spectroscopy also can be used to characterize modern resins as well as other types of plant exudates such as gums, gum resins, and kinos, which strongly resemble resins in appearance but have very different molecular constitutions. PMID:18925589

  16. ASSOCIATION BETWEEN RETINAL HARD EXUDATES AND DYSLIPIDEMIA IN TYPE 2 DIABETIC PATIENTS IN RURAL KARNATAKA

    Directory of Open Access Journals (Sweden)

    Arun Kumar B.

    2015-10-01

    Full Text Available AIM: To evaluate the association of elevated serum lipids with retinal hard exudates in type 2 diabetic patients in rural Karnataka. MATERIAL AND METHODS : Hospital based cross sectional study which included 60 (n=60 type 2 diabetic patients (60 eyes fulfilling the inclusion criteria. Patients were subjected to detailed ocular examination, fundus examination done under full dilatation using indirect ophth almoscope with 20D lens and slit lamp biomicroscope with 90D lens. Fundus photographs were obtained using fundus camera. Grading of retinal hard exudates performed by utilizing modified Airlie House classification. The modified Airlie House Classification used is as follows: Grade 0 - No evidence of hard exudates; Grade 1 : Questionable hard exudates present; Grade 2 : Hard exudates less than standard photograph 3; Grade 3 : Hard exudates greater than or equal to standard photograph 3, but less than standard p hotograph 5; Grade 4 : Hard exudates greater than or equal to standard photograph 5, but less than standard photograph 4 and Grade 5 : Hard exudates greater than or equal to standard photograph 4. These grades were further divided into three groups of patie nt severity as follows: Group 1 (absent or minimal hard exudates included patients with Grade 0, 1 or 2 hard exudates; Group 2 (hard exudates present included patients with Grade 3 or 4 hard exudates and Group 3 (prominent hard exudates included patient s with Grade 5 hard exudates. Fasting lipid profile including serum total cholesterol, low density lipoproteins, very low density lipoproteins, high density lipoproteins and triglycerides was obtained. Association of dyslipidemia with retinal hard exudates was analysed using one way ANOVA test. RESULTS: On statistical analysis with ANOVA test retinal hard exudates were significantly associated with elevated total cholesterol (p= .0001, triglycerides (p= .0001, serum LDL (p=.008, serum VLDL (p=.012, and negative correlation was found

  17. Roots Revisited.

    Science.gov (United States)

    Hughes, Barnabas

    1998-01-01

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

  18. Relationship Between Root Chemical Signals and Grain Quality of Rice

    Institute of Scientific and Technical Information of China (English)

    YANG Jian-chang; CHANG Er-hua; ZHANG Wen-jie; WANG Zhi-qin; LIU Li-jun

    2007-01-01

    This study was designed to elucidate the relationship between root chemical signals and the quality of rice. Various rice genotypes were used. Zeatin (Z) + zeatin riboside (ZR), abscisic acid (ABA), 1-aminocylopropane -1-carboxylic acid (ACC), and organic acids in roots during grain filling and the appearance quality, cooking/eating quality were investigated. The correlations among them were analyzed. The results showed that Z + ZR concentrations in the roots at mid- and lategrain-filling stages were significantly and positively correlated with the gel consistency and alkali spreading value (r = 0.72* - 0.90**), whereas negatively correlated with the amylose content (r = -0.68* - -0.78**). ABA concentrations in roots at mid- grain-filling stage were significantly and negatively correlated with the gel consistency and alkali spreading value (r = -0.90** - -0.91**), and positively correlated with the amylose content (r = 0.87**). ACC concentrations in root exudates at mid-grain-filling stage were very significantly correlated with the percentage of chalky grains and chalkiness (r = 0.97** -0.98**), and those at late-grain-filling stage Were significantly correlated with chalkiness and chalky size (r = 0.69*-0.96**). The more the malic acid and succinic acid exuded from roots for a cultivar, the greater the breakdown values and the smaller the setback values in the starch profile, and the results were reversed for a cultivar with more tartaric acid and citric acid exuded from roots during the grain-filling period. The cultivar with more lactic acid in exudates had smaller gel consistency and alkali spreading values, but had greater amylose content. When roots were treated with exogenous ZR, ABA, and ACC during grain filling, effects of the chemicals on the rice quality were consistent with the relationships of the endogenous hormones (Z + ZR, ABA, and ACC) with the quality indexes. Using rape cake as organic fertilizer can increase the concentrations of malic acid and

  19. Dynamic change of organic acids secreted from wheat roots in Mn deficiency

    Institute of Scientific and Technical Information of China (English)

    Zheng FANG; Zhenfeng AN; Yingli LI

    2008-01-01

    Through solution culture experiment and liquid chromatogram technique, two wheat (Triticum aestivum L.) genotypes with different tolerances to Mn deficiency were used to study the dynamic change of organic acids secreted from wheat root in the conditions of no Mn, low Mn and normal Mn supply. Nine kinds of organic acids were measured in wheat root exudate. The results showed that there were significant differences of organic acids in root exudate between tolerant genotype and susceptible genotype under Mn-stressed conditions. Tolerant genotype 9023 secreted more organic acids from the plant roots than susceptible genotype CM28. The main organic acid exudate included tartaric acid, malic acid, acetic acid, maleic acid and fumaric acid. Of all these acids, the amounts of tartaric acid and malic acid in root exudate showed significant differences between the tolerant genotype and susceptible genotype under Mn-stressed conditions. The results also indicated that secreting organic acids into root rhizosphere was an active response to Mn deficiency for the tolerant genotype of wheat.

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

    DEFF Research Database (Denmark)

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

    2005-01-01

    biomass and altered microbial community composition. These hypotheses were tested on cored soil samples from a UV reduction experiment with three filter treatments (Mylar, 60% UV-B reduction; Lexan, up to 90% UV-B reduction+UV-A reduction; UV transparent Teflon, filter control) and an open control...

  1. Enhancement of anti-inflammatory activity of Aloe vera adventitious root extracts through the alteration of primary and secondary metabolites via salicylic acid elicitation.

    Directory of Open Access Journals (Sweden)

    Yun Sun Lee

    Full Text Available Aloe vera (Asphodeloideae is a medicinal plant in which useful secondary metabolites are plentiful. Among the representative secondary metabolites of Aloe vera are the anthraquinones including aloe emodin and chrysophanol, which are tricyclic aromatic quinones synthesized via a plant-specific type III polyketide biosynthesis pathway. However, it is not yet clear which cellular responses can induce the pathway, leading to production of tricyclic aromatic quinones. In this study, we examined the effect of endogenous elicitors on the type III polyketide biosynthesis pathway and identified the metabolic changes induced in elicitor-treated Aloe vera adventitious roots. Salicylic acid, methyl jasmonate, and ethephon were used to treat Aloe vera adventitious roots cultured on MS liquid media with 0.3 mg/L IBA for 35 days. Aloe emodin and chrysophanol were remarkably increased by the SA treatment, more than 10-11 and 5-13 fold as compared with untreated control, respectively. Ultra-performance liquid chromatography-electrospray ionization mass spectrometry analysis identified a total of 37 SA-induced compounds, including aloe emodin and chrysophanol, and 3 of the compounds were tentatively identified as tricyclic aromatic quinones. Transcript accumulation analysis of polyketide synthase genes and gas chromatography mass spectrometry showed that these secondary metabolic changes resulted from increased expression of octaketide synthase genes and decreases in malonyl-CoA, which is the precursor for the tricyclic aromatic quinone biosynthesis pathway. In addition, anti-inflammatory activity was enhanced in extracts of SA-treated adventitious roots. Our results suggest that SA has an important role in activation of the plant specific-type III polyketide biosynthetic pathway, and therefore that the efficacy of Aloe vera as medicinal agent can be improved through SA treatment.

  2. Exudative Retinal Detachment Treatment in a Patient with Thrombotic Thrombocytopenic Purpura

    Directory of Open Access Journals (Sweden)

    Magali Sampo

    2016-02-01

    Full Text Available Purpose: We report a case of unilateral exudative retinal detachment in a patient with thrombotic thrombocytopenic purpura (TTP, without associated hypertension, successfully treated with plasmapheresis. Case Report: A 46-year-old woman with a medical history of TTP presented with unilateral exudative retinal detachment. Biological and radiological assessment eliminated other causes of exudative retinal detachment, including hypertension. Plasma exchange was performed, followed by a rapid improvement in visual acuity and total disappearance of serous detachment. Conclusion: Exudative unilateral retinal detachment is a rare complication of TTP and can be successfully treated by plasma exchange.

  3. Automatic Detection of Exudates in Diabetic Retinopathy Images

    Directory of Open Access Journals (Sweden)

    Ekkarat Pothiruk

    2012-01-01

    Full Text Available Problem statement: Diabetic Retinopathy (DR is globally the primary cause of visual impairment and blindness in diabetic patients. Retinal image is essential and crucial for ophthalmologists to diagnose diseases. Many of technique can achieve good performance on retinal feature are clearly visible. Unfortunately, it is a normal situation that the retinal images in Thailand are low-quality images. The existing algorithm cannot detect low-quality image. Therefore, this study is part of a larger effort to develop a new method for detection of exudates in low quality retinal image. Approach: In this study, we presented a new method towards the development for detecting exudates pathologies of DR. The color retinal images are segmented using Fuzzy C-Means (FCM clustering and morphological methods and following key preprocessing step, i.e., color normalization, contrast enhancement, remove noise and color space selection. This enables its difference in our methods compared to other approach and the algorithm can achieve good performance even on low-quality retinal images. Result/Conclusion: The result shows that accuracy values increase when the FCM clustering is combined with morphological methods techniques. If any applications need to detect maximum number of exudates pixels or require execution speed, the FCM clustering technique could be used in isolation. However, if the applications require higher accuracy, the FCM clustering combined with morphological methods should be chosen. This system intends to help ophthalmologists in DR screening process to detect symptoms faster and more easily. This is not a final result application but it can be a preliminary diagnosis tool or decision support system for ophthalmologists. Human ophthalmologists are still needed for the cases where detection results are not very obvious.

  4. Chemical and spectroscopic studies of Cercidium praecox gum exudate.

    Science.gov (United States)

    León de Pinto, G; Martínez, M; Rivas, C

    1994-07-01

    The structure of the polysaccharide from Cercidium praecox (R&P) Harms gum exudate has been studied by Smith degradation, by sugar and methylation analyses, and by 13C NMR spectroscopy. The results showed a (1-->4)-xylan core. Some xylose residues are substituted at O-2 by alpha-D-glucuronic acid and 4-O-methyl-alpha-D-glucuronic acid residues. beta-D-Glucuronic acid is present, probably as terminal residues. The arabinose is present as alpha-L-furanose and beta-L-pyranose. PMID:8062287

  5. Cell wall loosening proteins of the stigma exudate

    OpenAIRE

    Nieuwland, J.H.

    2004-01-01

    Outline of the thesis: The idea, formulated by Cosgrove, that cell wall loosening of the maternal tissue facilitates pollen tube growth is a central theme of this thesis. This idea was originally proposed for beta-expansins released by maize pollen. Since the pollen coat of dry stigma type plants, like maize, bears a functional similarity with the exudate of wet stigma type plants (e.g. tobacco and petunia), this research was started with the analysis of the putative function of the pistil-sp...

  6. Squalamine lactate for exudative age-related macular degeneration.

    Science.gov (United States)

    Connolly, Brian; Desai, Avinash; Garcia, Charles A; Thomas, Edgar; Gast, Michael J

    2006-09-01

    Squalamine lactate inhibits angiogenesis by a long-lived, intracellular mechanism of action. The drug is taken up into activated endothelial cells through caveolae, small invaginations in the cellular membrane. Subsequently, the drug binds to and "chaperones" calmodulin to an intracellular membrane compartment and blocks angiogenesis at several levels. A series of basic investigations, preclinical studies, and human clinical trials have begun to establish the proof of concept, efficacy, and safety parameters for use of squalamine lactate as a therapeutic agent for exudative age-related macular degeneration and several types of malignancies. PMID:16935213

  7. Crop systems and plant roots can modify the soil water holding capacity

    Science.gov (United States)

    Doussan, Claude; Cousin, Isabelle; Berard, Annette; Chabbi, Abad; Legendre, Laurent; Czarnes, Sonia; Toussaint, Bruce; Ruy, Stéphane

    2015-04-01

    At the interface between atmosphere and deep sub-soil, the root zone plays a major role in regulating the flow of water between major compartments: groundwater / surface / atmosphere (drainage, runoff, evapotranspiration). This role of soil as regulator/control of water fluxes, but also as a supporting medium to plant growth, is strongly dependent on the hydric properties of the soil. In turn, the plant roots growing in the soil can change its structure; both in the plow layer and in the deeper horizons and, therefore, could change the soil properties, particularly hydric properties. Such root-related alteration of soil properties can be linked to direct effect of roots such as soil perforation during growth, aggregation of soil particles or indirect effects such as the release of exudates by roots that could modify the properties of water or of soil particles. On an another hand, the rhizosphere, the zone around roots influenced by the activity of root and associated microorganisms, could have a high influence on hydric properties, particularly the water retention. To test if crops and plant roots rhizosphere may have a significant effect on water retention, we conducted various experiment from laboratory to field scales. In the lab, we tested different soil and species for rhizospheric effect on soil water retention. Variation in available water content (AWC) between bulk and rhizospheric soil varied from non-significant to a significant increase (to about 16% increase) depending on plant species and soil type. In the field, the alteration of water retention by root systems was tested in different pedological settings for a Maize crop inoculated or not with the bacteria Azospirillum spp., known to alter root structure, growth and morphology. Again, a range of variation in AWC was evidenced, with significant increase (~30%) in some soil types, but more linked to innoculated/non-innoculated plants rather than to a difference between rhizospheric and bulk soil

  8. Reversal of neurochemical alterations in the spinal dorsal horn and dorsal root ganglia by Mas-related gene (Mrg) receptors in a rat model of spinal nerve injury.

    Science.gov (United States)

    Wang, Dongmei; Xue, Yaping; Yan, Yanhua; Lin, Minjie; Yang, Jiajia; Huang, Jianzhong; Hong, Yanguo

    2016-07-01

    The rodent Mas-related gene (Mrg) receptor subtype C has been demonstrated to inhibit pathological pain. This study investigated the mechanisms underlying the reversal of pain hypersensitivity by the selective MrgC receptor agonist bovine adrenal medulla 8-22 (BAM8-22) in a rat model of L5 spinal nerve ligation (SNL). Intrathecal (i.t.) administration of BAM8-22 (0.1-10nmol) attenuated mechanical allodynia in a dose-dependent manner on day 10 after SNL. The antiallodynia effect of BAM8-22 was abolished by MrgC receptor antibody, but not by naloxone. I.t. BAM8-22 (10nmol) inhibited SNL-induced upregulation of neuronal nitric oxide synthesis (nNOS) and phosphorylation of cyclic AMP response element-binding protein (p-CREB) in the spinal dorsal horn. The BAM8-22 treatment reversed the SNL-induced astrocyte activation, increase of interleukin-1β (IL-1β) expression and phosphorylation of extracellular signal-regulated kinase (p-ERK) in the spinal cord. BAM8-22 also reversed the upregulation of fractalkine and IL-1β in small- and medium-sized dorsal root ganglion (DRG) neurons. Furthermore, the BAM8-22 exposure suppressed the lipopolysaccharide (LPS)-induced increase of nNOS and IL-1β in the DRG explant cultures and the BAM8-22-induced suppression disappeared in the presence of MrgC receptor antibody. The present study provides evidence that activation of MrgC receptors inhibits nerve injury-induced increase of pronociceptive molecules in DRG neurons, suppressing astrocyte activation, the upregulation of excitatory mediators and phosphorylation of transcription factors in the spinal dorsal horn. As MrgC receptors are unequally expressed in the dorsal root and trigeminal ganglia, this study suggests that targeting MrgC receptors could be a new therapy for neuropathic pain with limited unwanted effects. PMID:27018398

  9. TRANSGENIC PLANTS - INSECTICIDAL TOXIN IN ROOT EXUDATES FROM BT CORN. (R826107)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  10. Ecophysiological characterization of carnivorous plant roots: oxygen fluxes, respiration, and water exudation

    Czech Academy of Sciences Publication Activity Database

    Adamec, Lubomír

    2005-01-01

    Roč. 49, č. 2 (2005), s. 247-255. ISSN 0006-3134 R&D Projects: GA AV ČR(CZ) IAA6005909 Institutional research plan: CEZ:AV0Z6005908 Keywords : terrestrial carnivorous plants * soil anoxia * Genlisea traps Subject RIV: EF - Botanics Impact factor: 0.792, year: 2005

  11. Methods of collection of plant root exudates in relation to plant metabolism and purpose: A review

    Czech Academy of Sciences Publication Activity Database

    Vránová, V.; Rejšek, K.; Skene, K. R.; Janouš, Dalibor; Formanek, P.

    2013-01-01

    Roč. 176, č. 2 (2013), s. 175-199. ISSN 1436-8730 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) LM2010007 Institutional support: RVO:67179843 Keywords : allelochemical / CAM / C3 * C4 metabolism * retrieval * rhizodeposition * rhizosphere Subject RIV: EH - Ecology, Behaviour Impact factor: 1.663, year: 2013

  12. PHYTOREMEDIATION: PLANT UPTAKE OF ATRAZINE AND THE ROLE OF ROOT EXUDATES. (R825549C060)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  13. Intraspecific variability in allelopathy of Heracleum mantegazzianum is linked to the metabolic profile of root exudates

    OpenAIRE

    Jandová, Kateřina; Dostál, Petr; Cajthaml, Tomáš; KAMENÍK, Zdeněk

    2015-01-01

    Background and Aims Allelopathy may drive invasions of some exotic plants, although empirical evidence for this theory remains largely inconclusive. This could be related to the large intraspecific variability of chemically mediated plant–plant interactions, which is poorly studied. This study addressed intraspecific variability in allelopathy of Heracleum mantegazzianum (giant hogweed), an invasive species with a considerable negative impact on native communities and ecosystems.

  14. Amelioration of Pb and Mn toxicity to arbuscular mycorrhizal fungus Glomus intraradices by maize root exudates

    Czech Academy of Sciences Publication Activity Database

    Malcová, Radka; Gryndler, Milan

    2003-01-01

    Roč. 47, č. 2 (2003), s. 297-299. ISSN 0006-3134 R&D Projects: GA AV ČR KSK6005114; GA MŠk OC 838.10 Institutional research plan: CEZ:AV0Z6005908 Keywords : heavy metals * hyphal growth * Zea mays Subject RIV: EF - Botanics Impact factor: 0.919, year: 2003

  15. Comparison of the effect between pegaptanib and ranibizumab on exudative age-related macular degeneration with small lesion size

    Directory of Open Access Journals (Sweden)

    Fujihara M

    2012-03-01

    Full Text Available Yoshihiro Nishimura1,2, Maiko Taguchi1, Takafumi Nagai1, Masashi Fujihara1,2, Shigeru Honda2, Mamoru Uenishi11Department of Ophthalmology, Mitsubishi Kobe Hospital, Kobe, Japan; 2Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, Kobe, JapanPurpose: To compare the effect of pegaptanib versus ranibizumab on exudative age-related macular degeneration (AMD with small lesion size.Methods: This is a retrospective study of 81 eyes from 78 patients with exudative AMD treated and followed up over 12 months. Patients with baseline best corrected visual acuity (BCVA under 20/400 and with a greatest linear dimension of lesion over 4500 µm were excluded from the study. Twenty-six eyes from 25 patients were treated with three consecutive intravitreal injections of pegaptanib (IVP group and 55 eyes from 54 patients were treated with three consecutive ranibizumab injections (IVR group. Each therapy was repeated as needed. The alteration in BCVA was evaluated in the IVP and IVR groups.Results: No differences were detected in baseline parameters between the IVP and IVR groups. The mean BCVA (logMAR at month 1, 3, 6 and 12 after the initial treatment was improved from baseline in the IVP group (-0.095, -0.17, -0.18 and -0.18, respectively and in the IVR group (-0.077, -0.15, -0.17 and -0.11, respectively, which was statistically significant. There was no difference in the change in mean BCVA between IVP and IVR groups at the same time periods.Conclusions: The visual outcome of IVP was equivalent with IVR in exudative AMD with small lesion size.Keywords: pegaptanib, ranibizumab, age-related macular degeneration, small lesion size

  16. Alterations of the Danger Zone after Preparation of Curved Root Canals Using WaveOne with Reverse Rotation or Reciprocation Movements

    Science.gov (United States)

    Shantiaee, Yazdan; Dianat, Omid; Paymanpour, Payam; Nahvi, Golnaz; Ketabi, Mohammad Ali; Kolahi Ahari, Golbarg

    2015-01-01

    Introduction: The aim of this study was to compare the changes that occur in the danger zone (DZ) after preparation of curved mesiobuccal (MB) canals of mandibular first molars with WaveOne instruments in two different movements [reciprocation (RCP) and counter-clockwise rotation (CCWR)] by means of cone-beam computed tomography (CBCT). Methods and Materials: MB canals of 30 mandibular molars were randomly divided into 2 groups (n=15); WaveOne/RCP and WaveOne/CCWR. Pre- and post-instrumentation CBCT images were assessed for changes in the dentin thickness in DZ (2 and 4 mm below the highest point of the root furcation) in both groups. Data was analyzed using the repeated measures ANOVA test. Results: There was no statistically significant difference between two experimental groups in terms of remaining dentin thickness at 2 and 4 mm levels below the highest point of the furcation (P>0.05). Conclusion: The efficacy of WaveOne instrument on changes of the dentin thickness in the DZ was not affected by different file movements. PMID:26213536

  17. Alterations in Co2 fixation enzymes, Phosphatase Activity and Endogenous Phytohormones in P-deficient Callus induced from phloem of carrot (Daccus Carota) Roots

    International Nuclear Information System (INIS)

    A carrot callus liquid medium culture experiment was conducted to investigate the effects of P-deficiency on cellular responses separate from the whole plant response. Carrot (Daccus carota L.) callus was induced from the secondary phloem of the tap root. When explants were supplied with one-tenth the amount of Pi supplied to control explants (40 ppm), the concentration of P in callus was reduced by about 68% in a period of three weeks. This reduction in callus P was correlated with 48% reduction in callus fresh and dry weights. This effect was mediated through a reduction in cell number/callus by 48%. Meanwhile, the cell number/mg f.wt. of callus tissue was not affected in P-deficient treatment comparing to P-sufficient one, which might refer to a direct role of P-deficiency on the reduction of cell division. Although total N and soluble protein concentrations were not affected in P-deficient callus, chlorophyll concentration was reduced. In addition higher activity of acid phosphatase was obtained in P-deficient tissue reaching about 41% over its activity in P-sufficient callus which in turn could increase recycling process of P to spare available P for the newly formed cells. This was supported by the higher value of P utilization efficiency (d.wt. produced per unit P taken up) obtained from P-deficient callus

  18. Root interactions in a maize/soybean intercropping system control soybean soil-borne disease, red crown rot.

    Directory of Open Access Journals (Sweden)

    Xiang Gao

    Full Text Available BACKGROUND: Within-field multiple crop species intercropping is well documented and used for disease control, but the underlying mechanisms are still unclear. As roots are the primary organ for perceiving signals in the soil from neighboring plants, root behavior may play an important role in soil-borne disease control. PRINCIPAL FINDINGS: In two years of field experiments, maize/soybean intercropping suppressed the occurrence of soybean red crown rot, a severe soil-borne disease caused by Cylindrocladium parasiticum (C. parasiticum. The suppressive effects decreased with increasing distance between intercropped plants under both low P and high P supply, suggesting that root interactions play a significant role independent of nutrient status. Further detailed quantitative studies revealed that the diversity and intensity of root interactions altered the expression of important soybean PR genes, as well as, the activity of corresponding enzymes in both P treatments. Furthermore, 5 phenolic acids were detected in root exudates of maize/soybean intercropped plants. Among these phenolic acids, cinnamic acid was released in significantly greater concentrations when intercropped maize with soybean compared to either crop grown in monoculture, and this spike in cinnamic acid was found dramatically constrain C. parasiticum growth in vitro. CONCLUSIONS: To the best of our knowledge, this study is the first report to demonstrate that intercropping with maize can promote resistance in soybean to red crown rot in a root-dependent manner. This supports the point that intercropping may be an efficient ecological strategy to control soil-borne plant disease and should be incorporated in sustainable agricultural management practices.

  19. The regulation of gelation of Phloem exudate from cucurbita fruit by dilution, glutathione, and glutathione reductase.

    Science.gov (United States)

    Alosi, M C; Melroy, D L; Park, R B

    1988-04-01

    The average glutathione equivalent concentration in phloem exudate collected from squash fruit (Cucurbita moschata [Duchesne] Poir. var Butternut) and pumpkin fruit (Cucurbita pepo [L.] var Jack-o-lattern) was 1.02 and 0.60 millimolar, respectively. Glutathione reductase (EC 1.6.4.2) activity in phloem exudate from squash and pumpkin fruit averaged 0.48 and 1.74 micromole NADPH oxidized per minute per milliliter, respectively. Protein concentrations in fruit phloem exudates averaged 67 milligrams per milliliter for squash and 57 milligrams per milliliter for pumpkin. The phloem-specific P-proteins account for most of the protein content of exudate. Pure exudate from fruit does not gel for hours or days, but when diluted with neutral or alkaline aqueous solutions, exudate gels rapidly. Exudate solutions undergo biphasic pH changes with dilution. We suggest that P-protein undergoes conformational change upon dilution, exposing titratable groups and sulfhydryl residues. Oxidation of the latter forms the intermolecular disulfide bridges of the gel. The gelation of diluted exudate is regulated by factors (oxygen, pH, glutathione, NADPH) which affect the maintenance of reduced sulfhydryl residues and the activity of glutathione reductase. While these factors may also act in vivo to regulate redox conditions in phloem, their relationship to hypothetical sol/gel transitions or motile and nonmotile phases in the transport conduit is unknown. PMID:16666036

  20. Combined intravitreal bevacizumab with phacoemulsification in visually significant cataract and visually significant exudative maculopathy

    OpenAIRE

    Ahmad Mansour; Bashshur, Ziad F.; Sibai, Tarek A.; Abla Mehio-Sibai; Hamam, Rola N.

    2011-01-01

    Purpose : We investigated the visual outcome of combined phacoemulsification with intravitreal bevacizumab, in eyes with dense cataract and visually significant exudative maculopathy. Materials and Methods : Prospective longitudinal pilot study of consecutive patients treated by two surgeons in 2006, using intravitreal bevacizumab at the end of phacoemulsification. The historical control group consisted of consecutive subjects with exudative maculopathy and dense cataract treated by the s...

  1. Enhancement of Phloem Exudation from Fraxinus uhdei Wenz. (Evergreen Ash) using Ethylenediaminetetraacetic Acid.

    Science.gov (United States)

    Costello, L R; Bassham, J A; Calvin, M

    1982-01-01

    Ethylenediaminetetraacetic acid (EDTA) enhanced the exudation of (14)C-labeled assimilates from excised leaflets and whole plant specimens of Fraxinus uhdei Wenz. A 2 millimolar EDTA concentration was found to be most effective in promoting exudation from excised leaflets, while 10 millimolar EDTA was most effective in whole plants experiments. Exudation rate reached a maximum after 24 hours in both experiments. The continuous presence of EDTA throughout the treatment period was required for maximum exudation from excised leaflets. Stachyose, raffinose, verbascose, and sucrose were the principal compounds found to occur in exudate samples. These compounds are typically transported in sieve elements of various Fraxinus species suggesting the exudate was of phloem origin. Electron microscope studies of petiolule sieve plate pores from excised leaflets showed substantially less callose appearing after treatment with EDTA than after H(2)O treatment. It is suggested that EDTA enhances phloem exudation by inhibiting or reducing callose formation in sieve plate pores. The exudation enhancement technique described for whole plant specimens is suggested as a useful means of collecting phloem sap and studying translocation in woody plants. PMID:16662189

  2. Enhancement of phloem exudation from Fraxinus uhdei Wenz. (evergreen ash) using ethylenediaminetetraacetic acid

    International Nuclear Information System (INIS)

    Ethylenediaminetetraacetic acid (EDTA) enhanced the exudation of 14C-labeled assimilates from excised leaflets and whole plant specimens of Fraxinus uhdei Wenz. A 2 millimolar EDTA concentration was found to be most effective in promoting exudation from excised leaflets, while 10 millimolar EDTA was most effective in whole plants experiments. Exudation rate reached a maximum after 24 hours in both experiments. The continuous presence of EDTA throughout the treatment period was required for maximum exudation from excised leaflets. Stachyose, raffinose, verbascose, and sucrose were the principal compounds found to occur in exudate samples. These compounds are typically transported in sieve elements of various Fraxinus species suggesting the exudate was of phloem orgin. Electron microscope studies of petiolule sieve plate pores from excisd leaflets showed substantially less callose appearing after treatment with EDTA than after H2O treatment. It is suggested that EDTA enhances phloem exudation by inhibiting or reducing callose formation in sieve plate pores. The exudation enhancement technique described for whole plant specimens is suggested as a useful means of collecting phloem sap and studying translocation in woody plants

  3. Enhancement of phloem exudation from Fraxinus uhdei Wenz. (evergreen ash) using ethylenediaminetetraacetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Costello, L.R.; Bassham, J.A., Calvin, M.

    1982-01-01

    Ethylenediaminetetraacetic acid (EDTA) enhanced the exudation of /sup 14/C-labeled assimilates from excised leaflets and whole plant specimens of Fraxinus uhdei Wenz. A 2 millimolar EDTA concentration was found to be most effective in promoting exudation from excised leaflets, while 10 millimolar EDTA was most effective in whole plants experiments. Exudation rate reached a maximum after 24 hours in both experiments. The continuous presence of EDTA throughout the treatment period was required for maximum exudation from excised leaflets. Stachyose, raffinose, verbascose, and sucrose were the principal compounds found to occur in exudate samples. These compounds are typically transported in sieve elements of various Fraxinus species suggesting the exudate was of phloem orgin. Electron microscope studies of petiolule sieve plate pores from excisd leaflets showed substantially less callose appearing after treatment with EDTA than after H/sub 2/O treatment. It is suggested that EDTA enhances phloem exudation by inhibiting or reducing callose formation in sieve plate pores. The exudation enhancement technique described for whole plant specimens is suggested as a useful means of collecting phloem sap and studying translocation in woody plants.

  4. Enhancement of Phloem Exudation from Fraxinus uhdei Wenz. (Evergreen Ash) using Ethylenediaminetetraacetic Acid 1

    Science.gov (United States)

    Costello, L. R.; Bassham, James A.; Calvin, Melvin

    1982-01-01

    Ethylenediaminetetraacetic acid (EDTA) enhanced the exudation of 14C-labeled assimilates from excised leaflets and whole plant specimens of Fraxinus uhdei Wenz. A 2 millimolar EDTA concentration was found to be most effective in promoting exudation from excised leaflets, while 10 millimolar EDTA was most effective in whole plants experiments. Exudation rate reached a maximum after 24 hours in both experiments. The continuous presence of EDTA throughout the treatment period was required for maximum exudation from excised leaflets. Stachyose, raffinose, verbascose, and sucrose were the principal compounds found to occur in exudate samples. These compounds are typically transported in sieve elements of various Fraxinus species suggesting the exudate was of phloem origin. Electron microscope studies of petiolule sieve plate pores from excised leaflets showed substantially less callose appearing after treatment with EDTA than after H2O treatment. It is suggested that EDTA enhances phloem exudation by inhibiting or reducing callose formation in sieve plate pores. The exudation enhancement technique described for whole plant specimens is suggested as a useful means of collecting phloem sap and studying translocation in woody plants. Images PMID:16662189

  5. A review of the influence of root-associating fungi and root exudates on the success of invasive plants

    OpenAIRE

    Cindy Bongard

    2012-01-01

    Plant-fungal interactions are essential for understanding the distribution and abundance of plants species. Recently, arbuscular mycorrhizal fungal (AMF) partners of non-indigenous invasive plants have been hypothesized to be a critical factor influencing the invasion processes. AMF are known to improve nutrient and moisture uptake, as well as disrupt parasitic and pathogenic microbes in the host plant. Such benefits may enable invaders to establish significant and persistent populations in e...

  6. Major Alterations of the Regulation of Root NO3− Uptake Are Associated with the Mutation of Nrt2.1 and Nrt2.2 Genes in Arabidopsis1

    Science.gov (United States)

    Cerezo, Miguel; Tillard, Pascal; Filleur, Sophie; Muños, Stéphane; Daniel-Vedele, Françoise; Gojon, Alain

    2001-01-01

    The role of AtNrt2.1 and AtNrt2.2 genes, encoding putative NO3− transporters in Arabidopsis, in the regulation of high-affinity NO3− uptake has been investigated in the atnrt2 mutant, where these two genes are deleted. Our initial analysis of the atnrt2 mutant (S. Filleur, M.F. Dorbe, M. Cerezo, M. Orsel, F. Granier, A. Gojon, F. Daniel-Vedele [2001] FEBS Lett 489: 220–224) demonstrated that root NO3− uptake is affected in this mutant due to the alteration of the high-affinity transport system (HATS), but not of the low-affinity transport system. In the present work, we show that the residual HATS activity in atnrt2 plants is not inducible by NO3−, indicating that the mutant is more specifically impaired in the inducible component of the HATS. Thus, high-affinity NO3− uptake in this genotype is likely to be due to the constitutive HATS. Root 15NO3− influx in the atnrt2 mutant is no more derepressed by nitrogen starvation or decrease in the external NO3− availability. Moreover, the mutant also lacks the usual compensatory up-regulation of NO3− uptake in NO3−-fed roots, in response to nitrogen deprivation of another portion of the root system. Finally, exogenous supply of NH4+ in the nutrient solution fails to inhibit 15NO3− influx in the mutant, whereas it strongly decreases that in the wild type. This is not explained by a reduced activity of NH4+ uptake systems in the mutant. These results collectively indicate that AtNrt2.1 and/or AtNrt2.2 genes play a key role in the regulation of the high-affinity NO3− uptake, and in the adaptative responses of the plant to both spatial and temporal changes in nitrogen availability in the environment. PMID:11553754

  7. Soil transfers from valley oak (Quercus lobata Nee) stands increase ectomycorrhizal diversity and alter root and shoot growth on valley oak seedlings.

    Science.gov (United States)

    Berman, J T; Bledsoe, C S

    1998-02-01

    Soils from valley oak (Quercus lobata Nee) riparian areas of the Cosumnes River Nature Conservancy Preserve near Sacramento, California were added to growth medium of valley oak seedlings grown in a greenhouse or in agricultural fields at Cosumnes which probably once supported valley oak trees and are now replanted with native riparian vegetation or allowed to revegetate naturally. Agricultural field soil from the Cosumnes River Preserve was presumed to be low or lacking in ectomycorrhizal inoculum. The study was designed to (1) determine whether valley oak stand soil transfer could cause mycorrhizal infection on valley oak seedlings in an agricultural field and in a greenhouse, (2) describe ectomycorrhizal morphological types formed on valley oak seedlings, and (3) determine whether seedling growth is enhanced more by transfer of natural valley oak stand soil than agricultural field soil. In the field study, transfer of forest soil increased average ectomycorrhizal diversity (2.4 types) more than transfer of agricultural field soil (1.2 types). Valley oak seedlings were responsive to ectomycorrhizal infection in the field study. With increase in mycorrhizal infection there was an increase in shoot growth at the expense of root growth. In the greenhouse study, both percent mycorrhizal infection and mycorrhizal diversity were increased more by transfer of oak forest and woodland soils than agricultural field soil. Eight morphotypes occurred on seedlings in forest and woodland soils but only three morphotypes in agricultural soil. This result strongly suggests that the agricultural field also harbors ectomycorrhizal propagules but forest and woodland soils support a more abundant and diverse ectomycorrhizal flora. PMID:24578047

  8. Root fractures

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  9. COLONIZATION OF VIGNA RADIATA ROOTS BY CHROMIUM RESISTANT BACTERIAL STRAINS OF OCHROBACTRUM INTERMEDIUM, BACILLUS CEREUS AND BREVIBA CTERIUM SP.

    Institute of Scientific and Technical Information of China (English)

    MUHAMMAD Faisal; SHAHIDA Hasnain

    2005-01-01

    The present study deals with colonization potential of plant growth promoting bacterial strains ( Ochrobactrum intermedium, Bacillus cereus and Brevibacterium sp. ) on Vigna radiata roots. The roots were heavily colonized with O. intermedium and B. cereus as compared to Brevibacterium sp. O. intermedium mainly colonized rhizoplane while B. cereus occurred both on the rhizoplane and near root zone. O. intermedium and B. cereus were found to be present both on the rhizoplane and near root zone, while Brevibacterium only in the rhizosphere in the form of groups. The cells of B. cereus were found more in the sites where root exudates were existed. From the above results it was observed that the number of O. intermedium cells were large at root exudate site. Fig 2, Tab 1, Ref 15

  10. Square Root +

    Science.gov (United States)

    Frederiksen, John G.

    1969-01-01

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

  11. Mapping of Sugar and Amino Acid Availability in Soil around Roots with Bacterial Sensors of Sucrose and Tryptophan

    OpenAIRE

    Jaeger, C. H.; Lindow, S E; Miller, W.; Clark, E.; Firestone, M K

    1999-01-01

    We developed a technique to map the availability of sugars and amino acids along live roots in an intact soil-root matrix with native microbial soil flora and fauna present. It will allow us to study interactions between root exudates and soil microorganisms at the fine spatial scale necessary to evaluate mechanisms of nitrogen cycling in the rhizosphere. Erwinia herbicola 299R harboring a promoterless ice nucleation reporter gene, driven by either of two nutrient-responsive promoters, was us...

  12. Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates

    Directory of Open Access Journals (Sweden)

    AK Gregg

    2013-07-01

    Full Text Available Algae-derived dissolved organic matter has been hypothesized to induce mortality of reef building corals. One proposed killing mechanism is a zone of hypoxia created by rapidly growing microbes. To investigate this hypothesis, biological oxygen demand (BOD optodes were used to quantify the change in oxygen concentrations of microbial communities following exposure to exudates generated by turf algae and crustose coralline algae (CCA. BOD optodes were embedded with microbial communities cultured from Montastraea annularis and Mussismilia hispida, and respiration was measured during exposure to turf and CCA exudates. The oxygen concentrations along the optodes were visualized with a low-cost Submersible Oxygen Optode Recorder (SOOpR system. With this system we observed that exposure to exudates derived from turf algae stimulated higher oxygen drawdown by the coral-associated bacteria than CCA exudates or seawater controls. Furthermore, in both turf and CCA exudate treatments, all microbial communities (coral-, algae-associated and pelagic contributed significantly to the observed oxygen drawdown. This suggests that the driving factor for elevated oxygen consumption rates is the source of exudates rather than the initially introduced microbial community. Our results demonstrate that exudates from turf algae may contribute to hypoxia-induced coral stress in two different coral genera as a result of increased biological oxygen demand of the local microbial community. Additionally, the SOOpR system developed here can be applied to measure the BOD of any culturable microbe or microbial community.

  13. A Stable-Isotope Mass Spectrometry-Based Metabolic Footprinting Approach to Analyze Exudates from Phytoplankton

    Directory of Open Access Journals (Sweden)

    Mark R. Viant

    2013-10-01

    Full Text Available Phytoplankton exudates play an important role in pelagic ecology and biogeochemical cycles of elements. Exuded compounds fuel the microbial food web and often encompass bioactive secondary metabolites like sex pheromones, allelochemicals, antibiotics, or feeding attractants that mediate biological interactions. Despite this importance, little is known about the bioactive compounds present in phytoplankton exudates. We report a stable-isotope metabolic footprinting method to characterise exudates from aquatic autotrophs. Exudates from 13C-enriched alga were concentrated by solid phase extraction and analysed by high-resolution Fourier transform ion cyclotron resonance mass spectrometry. We used the harmful algal bloom forming dinoflagellate Alexandrium tamarense to prove the method. An algorithm was developed to automatically pinpoint just those metabolites with highly 13C-enriched isotope signatures, allowing us to discover algal exudates from the complex seawater background. The stable-isotope pattern (SIP of the detected metabolites then allowed for more accurate assignment to an empirical formula, a critical first step in their identification. This automated workflow provides an effective way to explore the chemical nature of the solutes exuded from phytoplankton cells and will facilitate the discovery of novel dissolved bioactive compounds.

  14. Piriformospora indica Stimulates Root Metabolism of Arabidopsis thaliana.

    Science.gov (United States)

    Strehmel, Nadine; Mönchgesang, Susann; Herklotz, Siska; Krüger, Sylvia; Ziegler, Jörg; Scheel, Dierk

    2016-01-01

    Piriformospora indica is a root-colonizing fungus, which interacts with a variety of plants including Arabidopsis thaliana. This interaction has been considered as mutualistic leading to growth promotion of the host. So far, only indolic glucosinolates and phytohormones have been identified as key players. In a comprehensive non-targeted metabolite profiling study, we analyzed Arabidopsis thaliana's roots, root exudates, and leaves of inoculated and non-inoculated plants by ultra performance liquid chromatography/electrospray ionization quadrupole-time-of-flight mass spectrometry (UPLC/(ESI)-QTOFMS) and gas chromatography/electron ionization quadrupole mass spectrometry (GC/EI-QMS), and identified further biomarkers. Among them, the concentration of nucleosides, dipeptides, oligolignols, and glucosinolate degradation products was affected in the exudates. In the root profiles, nearly all metabolite levels increased upon co-cultivation, like carbohydrates, organic acids, amino acids, glucosinolates, oligolignols, and flavonoids. In the leaf profiles, we detected by far less significant changes. We only observed an increased concentration of organic acids, carbohydrates, ascorbate, glucosinolates and hydroxycinnamic acids, and a decreased concentration of nitrogen-rich amino acids in inoculated plants. These findings contribute to the understanding of symbiotic interactions between plant roots and fungi of the order of Sebacinales and are a valid source for follow-up mechanistic studies, because these symbioses are particular and clearly different from interactions of roots with mycorrhizal fungi or dark septate endophytes. PMID:27399695

  15. Roots & Hollers

    OpenAIRE

    Kollman, Patrick L; Gorman, Thomas A.

    2011-01-01

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

  16. Early and exudative age-related macular degeneration is associated with increased plasma levels of soluble TNF receptor II

    DEFF Research Database (Denmark)

    Faber, Carsten; Jehs, Tina; Juel, Helene Baek; Singh, Amardeep; Falk, Mads Krüger; Sørensen, Torben Lykke; Nissen, Mogens Holst

    2015-01-01

    PURPOSE: We have recently identified homeostatic alterations in the circulating T cells of patients with age-related macular degeneration (AMD). In cultures of retinal pigment epithelial cells, we have demonstrated that T-cell-derived cytokines induced the upregulation of complement, chemokines and...... other proteins implicated in AMD pathogenesis. The purpose of this study was to test whether increased plasma levels of cytokines were present in patients with AMD. METHODS: We conducted a case-control study. Age-related macular degeneration status was assessed using standardized multimodal imaging...... forms of AMD and 74 controls. Significantly increased levels of sTNFRII were observed in patients with early or exudative AMD (p < 0.01). After adjusting for CFH Y402H genotype, age, sex and smoking history, the level of sTNFRII remained a significant predictor for prevalence of AMD with odds ratios at...

  17. Evaluation of factors influencing root-induced changes of copper fractionation in rhizosphere of a calcareous soil

    International Nuclear Information System (INIS)

    Major factors influencing the root-induced copper fractionation changes within the rhizosphere of maize, wheat, pea, and soybean seedlings were evaluated using a contaminated calcareous soil. The effects of acidification, alkalization, and introduction of root exudates were investigated by addition of acid, alkaline and root exudates from solution cultures, prior to incubation and copper fractionation. Raw and sterilized soils were compared for changes of copper fractionation in the rhizosphere using rhizoboxes with maize, wheat, pea and soybean seedlings. The results indicated that the general trend in considerable changes was similar among the plant species studied. The rhizosphere experienced a depletion of carbonate associated and organic bound copper along with an accumulation of exchangeable and Fe-Mn oxide bound copper. The resulting significant influence of root exudates on copper fractionation appears to have been produced through complexation rather than acidification or alkalization. The increase in exchangeable copper in rhizosphere was strengthened by microorganisms. - Influence of root exudates on copper fractionation appeared to be due to complexation, rather than acidification or alkalisation

  18. Effect of Human Burn Wound Exudate on Pseudomonas aeruginosa Virulence.

    Science.gov (United States)

    Gonzalez, Manuel R; Fleuchot, Betty; Lauciello, Leonardo; Jafari, Paris; Applegate, Lee Ann; Raffoul, Wassim; Que, Yok-Ai; Perron, Karl

    2016-01-01

    Burn wound sepsis is currently the main cause of morbidity and mortality after burn trauma. Infections by notorious pathogens such as Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii impair patient recovery and can even lead to fatality. In this study, we investigated the effect of burn wound exudates (BWEs) on the virulence of those pathogens. BWEs were collected within 7 days after burn trauma from 5 burn patients. We first monitored their effect on pathogen growth. In contrast to A. baumannii and S. aureus, P. aeruginosa was the only pathogen able to grow within these human fluids. Expression of typical virulence factors such as pyocyanin and pyoverdine was even enhanced compared the levels seen with standard laboratory medium. A detailed chemical composition analysis of BWE was performed, which enabled us to determine the major components of BWE and underline the metabolic modifications induced by burn trauma. These data are essential for the development of an artificial medium mimicking the burn wound environment and the establishment of an in vitro system to analyze the initial steps of burn wound infections. IMPORTANCE Microbial infection of severe burn wounds is currently a major medical challenge. Of the infections by bacteria able to colonize such injuries, those by Pseudomonas aeruginosa are among the most severe, causing major delays in burn patient recovery or leading to fatal issues. In this study, we investigated the growth properties of several burn wound pathogens in biological fluids secreted from human burn wounds. We found that P. aeruginosa strains were able to proliferate but not those of the other pathogens tested. In addition, burn wound exudates (BWEs) stimulate the expression of virulence factors in P. aeruginosa. The chemical composition analysis of BWEs enabled us to determine the major components of these fluids. These data are essential for the development of an artificial medium mimicking the burn wound

  19. The Effect of Nutritional Conditions on Root Metabolism and the Quantitative and Qualitative Composition of Nitrogenous Compounds Translocated from the Roots to the Aerial Parts of Plants

    International Nuclear Information System (INIS)

    Experiments were carried out with maize cultivated under normal conditions of nutrition and under conditions of nitrogen and phosphorus deficiency. The results obtained show that a deficiency of these elements has a very marked effect on root metabolic processes connected with the uptake, conversion and translocation of nitrogen. Under conditions of nitrogen deficiency the amount of amino acids translocated from the roots to the aerial parts of the plant drops sharply. This is accompanied by a marked change in the qualitative composition of the amino acids, which ultimately affects the operation of the synthesizing mechanism of the aerial organs. After addition of nitrogen to 30-day maize plants, rapid amino acid synthesis in the roots was observed, and the amount of free amino acids translocated from the roots to the aerial parts increased by a factor of 12 in the two hours following addition of the nitrogen. With the use of 15N , introduced into the nutrient medium as ammonium nitrate and calcium nitrate, it was found that the nitrogen taken up by the roots was preferentially incorporated into the amino acids and amides originating from the ketonic acids of the Krebs cycle. O f the total amount of amino acids translocated from the roots to the aerial parts, more than 50 % was accounted for by glutamine, alanine and aspartic acid. The results obtained give grounds for believing that variations in the conditions of nutrition affect the nitrogen metabolism of plants mainly through the metabolism of nitrogenous substances in the roots. The paper contains the following tables: 1. Concentration of different nitrogen fractions in maize exudate; 2. Increase in the concentration of amino acids in maize exudate 24 hours after the addition of nitrogen to the P K variety; 3. Effect of nutritional conditions on the concentration of different nitrogen fractions in maize exudate during vegetation; 4. Effect of nutritional conditions on the concentration of different free amino

  20. Root Associated Bacteria – Friends or Enemies? A Review

    Directory of Open Access Journals (Sweden)

    Gabriela Mihalache

    2015-10-01

    Full Text Available Plant roots, due to their exudates, represent important ecological niches for bacteria, which can influence the plant growth by their both beneficial and deleterious effects. The positive effects of bacteria interaction with the plants roots consist in facilitating the nutrient uptake (N, P, producing phytohormones, enhancing their resistance to biotic and abiotic factors such as pathogenic fungi and bacteria, extreme temperatures, heavy metals, salinity. Regarding the harmful effects of bacteria on plants growth, production of phytotoxins, competition for nutrients or inducing diseases or even plants death represents examples of mechanisms by which bacteria can affect in a negative manner the growth of the plants.

  1. Alterações na qualidade de raízes de mandioca(Manihot esculenta Crantz minimamente processadas Quality alterations in cassava roots (Manihot esculenta Crantz minimally processed

    Directory of Open Access Journals (Sweden)

    Andreia Alves

    2005-04-01

    Full Text Available A conservação pós-colheita das raízes de mandioca tem sido uma preocupação das indústrias e produtores, devido ao curto tempo de estocagem e a alta perecibilidade das raízes. Dois fenômenos são apontados como responsáveis pela deterioração das raízes, um de ordem fisiológica, provocando a perda inicial da qualidade por meio do desenvolvimento da descoloração vascular do tecido parenquimatoso, e o outro, de ordem microbiana, que se segue à fisiologia, responsável pela decomposição do produto. Dessa forma, com o presente trabalho, objetivou-se estudar a conservação das raízes de mandioca (Manihot esculenta Crantz, submetidas à higienização em água clorada e armazenadas em três tipos de embalagens, bandeja de isopor envolta em filme de policloreto de vinila (PVC, embalagem multicamada (poliéster Saram-13,5µ/polietileno-100µ com e sem vácuo e resfriadas (5 ± 0,5°C, mediante análises físico-químicas, microbiológicas, fisiológicas e sensoriais. A conservação de mandioca minimamente processada sob refrigeração para os tratamentos realizados, é possível diferenciando-se o período de armazenamento, sendo que para as amostras armazenadas em bandeja, o período de armazenamento foi de 7 dias, no selado e a vácuo foi de aproximadamente 24 dias, respectivamente.Post harvest of cassava roots has been a great concern in food industries and producers due to the short shelf life and high perishability. Several phenomena have been pointed out as responsible for root deterioration. Among them there are physiological aspects, that lead to losses in initial quality through vascular discoloration of parenchymatous tissue. On the other hand, phenomena from microbial origin, which follow the physiological alterations, are responsible for product decomposition. In this context, this work was aimed at investigating the conservation of cassava roots (Manihot esculenta Crantz submitted to chlorinated water, and stored using

  2. Chemotactic response of plant-growth-promoting bacteria towards roots of vesicular-arbuscular mycorrhizal tomato plants.

    Science.gov (United States)

    Gupta Sood, Sushma

    2003-08-01

    The chemotactic responses of the plant-growth-promoting rhizobacteria Azotobacter chroococcum and Pseudomonas fluorescens to roots of vesicular-arbuscular mycorrhizal (Glomus fasciculatum) tomato plants were determined. A significantly (P=0.05) greater number of bacterial cells of wild strains were attracted towards vesicular-arbuscular mycorrhizal tomato roots compared to non-vesicular-arbuscular mycorrhizal tomato roots. Substances exuded by roots served as chemoattractants for these bacteria. P. fluorescens was strongly attracted towards citric and malic acids, which were predominant constituents in root exudates of tomato plants. A. chroococcum showed a stronger response towards sugars than amino acids, but the response was weakest towards organic acids. The effects of temperature, pH, and soil water matric potential on bacterial chemotaxis towards roots were also investigated. In general, significantly (P=0.05) greater chemotactic responses of bacteria were observed at higher water matric potentials (0, -1, and -5 kPa), slightly acidic to neutral pH (6, 6.5 and 7), and at 20-30 degrees C (depending on the bacterium) than in other environmental conditions. It is suggested that chemotaxis of P. fluorescens and A. chroococcum towards roots and their exudates is one of the several steps in the interaction process between bacteria and vesicular-arbuscular mycorrhizal roots. PMID:19719591

  3. A critical review of modern and emerging absorbent dressings used to treat exuding wounds.

    Science.gov (United States)

    Sweeney, India R; Miraftab, Mohsen; Collyer, Graham

    2012-12-01

    Wound management has progressed significantly over the last five decades. This emanates from a greater understanding of wound healing, technological progression and improved clinical and scientific research. There are currently a plethora of absorbent dressings on the wound care market which claim to have the ability to manage exudates whilst encouraging healing. However, it is becoming clear, from analysing randomised controlled trials, that some of these absorbent dressings are not meeting their expectations when applied in a clinical setting. Many clinicians now feel that there should be more focus, not only on a dressing's ability to manage exudate efficiently, but on a dressing's ability to proactively encourage healing and thus exudate reduction will ensue. This paper proposes to critically review modern and emerging absorbent wound care dressings used to manage exuding wounds and discuses some advances in this area. PMID:22248337

  4. Automatic Detection of Exudates in Retinal Fundus Images using Differential Morphological Profile

    Directory of Open Access Journals (Sweden)

    Shraddha Tripathi

    2013-06-01

    Full Text Available This paper presents an automatic method for exudate detection from colour fundus imagesbased on Differential Morphological Profile (DMP.The detection of exudates is important for the identification of eye diseases such as diabetic retinopathy. The method involves of three main phases. Inthe first phase, pre processing tasks like Gaussian smoothing and contrast enhancement is done. In the second phase, DMP is applied on the pre-processed image. The image obtained from DMP containshighlighted bright regions consisting of exudates and optic disc. In the next phase, feature extraction based on location of optic disc, shape index and area is done to obtain actual exudates. The performance of the proposed method is evaluated by applying it on the DIARETDB1 database. The specificity,sensitivity and PPV of the proposed method were compared with two other methods. The results showthat the proposed method gives better results than the other conventional methods.

  5. Wheat-Exuded Organic Acids Influence Zinc Release from Calcareous Soils

    Institute of Scientific and Technical Information of China (English)

    M. A. MAQSOOD; S. HUSSAIN; T. AZIZ; M. ASHRAF

    2011-01-01

    Rhizosphere drives plant uptake of sparingly soluble soil zinc (Zn).An investigation with three experiments was conducted to study organic acid exudation by two contrasting wheat genotypes (Sehar-06 and Vatan),Zn fractious in 10 different calcareous soils from Punjab,Pakistan,and release of different soil Zn fractions by organic acids.The two genotypes differed significantly in biomass production and Zn accumulation under deficient and optimum Zn levels in nutrient solution.At a deficient Zn level,Sehar-06 released more maleic acid in the rhizosphere than Vatan.Ten soils used in the present study had very different physicochemical properties; their total Zn and Zn distribution among different fractions varied significantly.Zinc release behaviour was determined by extracting the soils with 0.005 mol L-1 citric acid or maleic acid.The parabolic diffusion model best described Zn release as a function of time.Parabolic diffusion model fitting indicated more maleic acid-driven than citric acid-driven soil Zn mobility from different fractions.Cumulative Zn release in six consecutive extractions during 24 h ranged from 1.85 to 13.58 mg kg-1 using maleic acid and from 0.37 to 11.84 mg kg-1 using citric acid.In the selected calcareous soils,the results of stepwise linear regression indicated significant release of Fe-Mn oxide-bounded soil Zn by maleic acid and its availability to the Zn-efficient genotype.Hence,release of maleic acid by plants roots played an important role in phytoavailability of Zn from calcareous soils.

  6. Tachyphylaxis during ranibizumab treatment of exudative age-related macular degeneration

    Institute of Scientific and Technical Information of China (English)

    Sibel; Doguizi; Sengul; Ozdek; Selcen; Yuksel

    2015-01-01

    <正>Dear Editor,We are intestigators from Turkey primarily studying exudative age-related macular degeneration(AMD).Here we present the results of our retrospective clinical study on tachyphylaxis development during the treatment of exudative AMD with ranibizumab,which,we believe,will form a basis for further prospective studies to predict the drug response in anti-vascular endothelial growth factor

  7. TableCross: Exuding a Shared Space into Personal Spaces to Encourage Its Voluntary Maintenance

    OpenAIRE

    Nishimoto, Kazushi; Ikenoue, Akari; Shimizu, Koji; Tajima, Tomonori; Tanaka, Yuta; Baba, Yutaka; Wang, Xihong

    2011-01-01

    A shared space should be cooperatively maintained by all users. However, due to social loafing, often nobody maintains it and its condition worsens. We propose exudation of a shared space. Part of a shared space is exuded into personal workspaces so that office workers are forced to subjectively experience the atmosphere of the shared space, even while they remain at their personal workspaces. This paper illustrates the first prototype named “TableCross,” which reflects the degree of disorder...

  8. Atypical presentation of ocular toxoplasmosis: A Case report of exudative retinal detachment and choroidal Ischemia

    Directory of Open Access Journals (Sweden)

    Yahya A Al-Zahrani

    2016-01-01

    Full Text Available A 24-year-old healthy male presented with a chief complaint of blurred vision in the right eye for 1-week. Fundus examination indicated right exudative retinal detachment and choroidal ischemia. The patient responded well to anti-toxoplasmosis medications and steroids. Exudative retinal detachment and choroidal ischemia are atypical presentations of ocular toxoplasmosis. However, both conditions responded well to anti.parasitic therapy with steroid.

  9. Early Signs of Exudative Age-Related Macular Degeneration in Asians

    OpenAIRE

    Sasaki, Mariko; Kawasaki, Ryo; Uchida, Atsuro; Koto, Takashi; Shinoda, Hajime; Tsubota, Kazuo; Wong, Tien Yin; Ozawa, Yoko

    2014-01-01

    ABSTRACT Purpose To investigate the relationship between the early signs of age-related macular degeneration (AMD) and the risk of developing exudative AMD (typical AMD or polypoidal choroidal vasculopathy [PCV]) in the fellow eye of Japanese patients with unilateral exudative AMD, focusing particularly on eyes with only pigmentary abnormality. Methods This study is a retrospective observational consecutive case series. We retrospectively reviewed the medical charts of patients who revisited ...

  10. Effect of intravitreal bevacizumab on diabetic macular edema with hard exudates

    OpenAIRE

    Lee, Won Ki

    2014-01-01

    Sohee Jeon, Won Ki LeeDepartment of Ophthalmology, Seoul St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, KoreaBackground: We evaluated the efficacy of intravitreal bevacizumab on diabetic macular edema with subfoveal and perifoveal hard exudates.Materials and methods: Eleven eyes (11 patients) exhibiting diabetic macular edema with subfoveal and perifoveal hard exudates were included in this prospective, nonrandomized interventional pilot study. All...

  11. Effect of intravitreal bevacizumab on diabetic macular edema with hard exudates

    OpenAIRE

    Jeon S.; Lee WK

    2014-01-01

    Sohee Jeon, Won Ki LeeDepartment of Ophthalmology, Seoul St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, KoreaBackground: We evaluated the efficacy of intravitreal bevacizumab on diabetic macular edema with subfoveal and perifoveal hard exudates.Materials and methods: Eleven eyes (11 patients) exhibiting diabetic macular edema with subfoveal and perifoveal hard exudates were included in this prospective, nonrandomized interventional pilot study. All pat...

  12. Exudative Inflammatory Eye Response in Cataract Surgery: Current View on the Problem

    OpenAIRE

    Belousova N.Y.

    2011-01-01

    There has been analyzed one of the most frequent and serious complications of cataract surgery — exudative inflammatory response (EIR) of eye. There has been presented current view on etiopathogenesis of the condition, classifications and the description of clinical presentation of various EIR types have been given. Known techniques of prognosis and prevention of postoperative exudative uveites have been presented. There have been given present methods of complex treatment of eye EIR: drug tr...

  13. Rheological Modeling and Characterization of Ficus platyphylla Gum Exudates

    Directory of Open Access Journals (Sweden)

    Nnabuk O. Eddy

    2013-01-01

    Full Text Available Ficus platyphylla gum exudates (FP gum have been analyzed for their physicochemical parameters and found to be ionic, mildly acidic, odourless, and yellowish brown in colour. The gum is soluble in water, sparingly soluble in ethanol, and insoluble in acetone and chloroform. The nitrogen (0.39% and protein (2.44% contents of the gum are relatively low. The concentrations of the cations were found to increase according to the following trend, Mn>Fe>Zn>Pb>Cu>Mg>Cd>Ca. Analysis of the FTIR spectrum of the gum revealed vibrations similar to those found in polysaccharides while the scanning electron micrograph indicated that the gum has irregular molecular shapes, arranged randomly. The intrinsic viscosity of FP gum estimated by extrapolating to zero concentrations in Huggins, Kraemer, Schulz-Blaschke, and Martin plots has an average value of 7 dL/g. From the plots of viscosity versus shear rate/speed of rotation and also that of shear stress versus shear rate, FP gum can be classified as a non-Newtonian gum with characteristics-plastic properties. Development of the Master_s curve for FP gum also indicated that the gum prefers to remain in a dilute domain (C

  14. [THE MORPHOMETRY IN CYTOLOGICAL ANALYSIS OF EXUDATIVE FLUIDS].

    Science.gov (United States)

    Snikhovskaya, K V; Shabalova, I P

    2015-08-01

    The cytological technique takes a leading position in diagnostic of tumor processes according exudative fluids. However, its results depend on large number of subjective factors. The morphometry is one of techniques by virtue of which objectification of data of cytological analysis is possible. The study was carried out to establish differences of morphometric parameters of benign and malignant cells of pleural effusion. The morphometric analysis of cells of mesothelium, breast cancer, adenocarcinoma of lung and adenocarcinoma of stomach was implemented. The parameters characterizing size (area, perimeter) and form (form factor) of nucleus and cell, nucleus-cytoplasm ratio. The results demonstrated that in pleural effusion between cells of proliferating mesothelium and malignant neoplasms exist significant differences in morphometric parameters (p<0.001). The differences between area of nuclei and cells are especially significant. The comparison of data of morphometry of cells of breast cancer; adenocarcinoma of lung and adenocarcinoma of stomach demonstrated that despite of some morphological similarities, analysis of morphometric parameters can provide important data for proper establishment of cytological diagnosis. PMID:26596045

  15. Familial Exudative Vitreoretinopathy: Follow-Up and Treatment Results

    Directory of Open Access Journals (Sweden)

    Zafer Cebeci

    2014-10-01

    Full Text Available Objectives: To report the follow-up and treatment results of cases with the diagnosis of familial exudative vitreoretinopathy (FEVR in our clinic. Materials and Methods: We retrospectively reviewed the records of 19 eyes of 10 cases of FEVR that were followed up and some of them were treated in our clinic. Results: Nine male and one female patients with a mean age of 10.1 (3-30 years were included in the study. Seven patients had a family history of FEVR. Twelve eyes of 8 patients had laser photocoagulation to peripheral avascular areas, 3 patients had vitreoretinal surgery on one of their eyes three times. Unilateral total retinal detachment was determined in two patients at the initial visit and in three patients at the follow-up visits; because no improvement in the vision was expected, surgery was not done. Conclusion: FEVR is an inherited disease that can be detected in any age and can cause severe vision loss. These patients should be followed up throughout the life, and the essential treatment at the appropriate time can lead to partial visual recovery. (Turk J Ophthalmol 2014; 44: 370-3

  16. Concurrent synthesis and release of nod-gene-inducing flavonoids from alfalfa roots

    International Nuclear Information System (INIS)

    Flavonoid signals from alfalfa (Medicago sativa L.) induce transcription of nodulation (nod) genes in Rhizobium meliloti. Alfalfa roots release three major nod-gene inducers: 4',7-dihydroxyflavanone, 4',7-dihydroxyflavone, and 4,4'-dihydroxy-2'-methoxychalcone. The objective of the present study was to define temporal relationships between synthesis and exudation for those flavonoids. Requirements for concurrent flavonoid biosynthesis were assessed by treating roots of intact alfalfa seedlings with [U-14C]-L-phenylalanine in the presence or absence of the phenylalanine ammonia-lyase inhibitor L-2-aminoxy-3-phenylpropionic acid (AOPP). In the absence of AOPP, each of the three flavonoids in exudates contained 14C. In the presence of AOPP, 14C labeling and release of all the exuded nod-gene inducers were reduced significantly. AOPP inhibited labeling and release of the strongest nod-gene inducer, methoxychalcone, by more than 90%. The release process responsible for exudation of nod-gene inducers appears to be specific rather than a general phenomenon such as a sloughing off of cells during root growth

  17. Root resorption

    DEFF Research Database (Denmark)

    Kjaer, Inger

    2014-01-01

    Introduction: This paper summarizes the different conditions, which have a well-known influence on the resorption of tooth roots, exemplified by trauma and orthodontic treatment. The concept of the paper is to summarize and explain symptoms and signs of importance for avoiding resorption during...... orthodontic treatment. The Hypothesis: The hypothesis in this paper is that three different tissue layers covering the root in the so-called periroot sheet can explain signs and symptoms of importance for avoiding root resorption during orthodontic treatment. These different tissue layers are; outermost......-an ectodermal tissue layer (Malassez′s epithelium), a middle layer-composed by the collagen-mesodermal tissue layer, and an innermost root-close innervation layer. Abnormalities in one of these tissue layers are thought to cause inflammatory processes in the periodontal membrane comparable to inflammatory...

  18. Antitumor activity of fermented noni exudates and its fractions.

    Science.gov (United States)

    Li, Jinhua; Chang, Leng-Chee; Wall, Marisa; Wong, D K W; Yu, Xianzhong; Wei, Yanzhang

    2013-01-01

    Noni has been extensively used in folk medicine by Polynesians for over 2000 year. Recent studies have shown that noni has a wide spectrum of therapeutic activities including inhibition of angiogenesis, anti-inflammatory effects and anti-cancer activities. Intraperitoneal (i.p.) injection of fermented noni exudates (fNE) were previously found to induce significant tumor rejection in a S180 mouse sarcoma tumor model, while natural killer (NK) cells were demonstrated to be markedly involved in fNE-induced antitumor activity. In this study, fNE was partitioned into three fractions and their antitumor effects were examined using i.p. injection or as water supplement. The in vivo animal study results showed that when delivered by i.p. injection, n-butanol fraction of fNE (BuOH) effectively rejected (100%) tumor challenge and eradicated existing tumors (75%). When delivered as a water supplement, 62.5% of the mice receiving the n-butanol or ethyl acetate fractions resisted tumor cells. The tumor-resistant mice effectively rejected more and higher doses of tumor challenge, indicating that the immune system was activated. The findings confirm those of an earlier study showing fNE to have anti-tumor activity and demonstrating that the n-butanol fraction of fNE contains active antitumor components, to be further identified. More importantly, the antitumor effect of fNE and its fractions as water supplements renders a significant potential for identifying novel and powerful new dietary products for cancer prevention. PMID:24649140

  19. Plants influence on arsenic availability and speciation in the rhizosphere, roots and shoots of three different vegetables

    International Nuclear Information System (INIS)

    The toxicity of arsenic (As) in the environment is controlled by its concentration, availability and speciation. The aims of the study were to evaluate the accumulation and speciation of As in carrot, lettuce and spinach cultivated in soils with various As concentrations and to estimate the concomitant health risks associated with the consumption of the vegetables. Arsenic concentration and speciation in plant tissues and soils was analysed by HPLC, AAS and XANES spectroscopy. To estimate the plants influence in the rhizosphere, organic acids in lettuce root exudates were analysed by ion chromatography. The results showed that the As accumulation was higher in plants cultivated in soil with higher As extractability. Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. Succinic acid was the major organic acid in lettuce root exudates. Ingestion of the tested vegetables may result in an intake of elevated levels of inorganic As. -- Highlights: • In soils with higher arsenic extractability, accumulation in plants was higher. • Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. • Arsenite predominated in the shoots of healthy looking vegetables. -- Regardless of the initial level of extractable As in the soil, the plants almost doubled the extractable As in the rhizosphere soil

  20. INSECTICIDAL TOXIN FROM BACILLUS THURINGIENSIS IS RELEASED FROM ROOTS OF TRANSGENIC BT CORN IN VITRO AND IN SITU. (R826107)

    Science.gov (United States)

    AbstractThe insecticidal toxin encoded by the cry1Ab gene from Bacillus thuringiensis was released in root exudates from transgenic Bt corn during 40 days of growth in soil amended to 0, 3, 6, 9, or 12% (v/v) with montmorillonite or kaolinite in a...

  1. Targeted expression of SbMATE in the root distal transition zone is responsible for sorghum aluminum resistance

    Science.gov (United States)

    Aluminum (Al) toxicity is one of the major limiting factors for crop production on acid soils that comprise significant portions of the world’s lands. Al resistance in the cereal crop, Sorghum bicolor, is mainly achieved by Al-activated root apical citrate exudation, which is mediated by the plasma ...

  2. Effect of intravitreal bevacizumab on diabetic macular edema with hard exudates

    Directory of Open Access Journals (Sweden)

    Jeon S

    2014-08-01

    Full Text Available Sohee Jeon, Won Ki LeeDepartment of Ophthalmology, Seoul St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, KoreaBackground: We evaluated the efficacy of intravitreal bevacizumab on diabetic macular edema with subfoveal and perifoveal hard exudates.Materials and methods: Eleven eyes (11 patients exhibiting diabetic macular edema with subfoveal and perifoveal hard exudates were included in this prospective, nonrandomized interventional pilot study. All patients were treated with monthly scheduled intravitreal bevacizumab injections for 6 months. Changes in the Early Treatment Diabetic Retinopathy Study best corrected visual acuity, amount of hard exudates on fundus photography, and macular edema detected by central subfield thickness on spectral domain optical coherence tomography after six serial injections, were assessed. The amount of hard exudates at each visit was evaluated as pixels in fundus photography, using an Adobe Photoshop program. Results: Ten of 11 patients completed follow-up. The mean Early Treatment Diabetic Retinopathy Study best corrected visual acuity was 59.9±5.7 letters (Snellen equivalent, 20/63 at baseline evaluation. The best corrected visual acuity exhibited no significant difference at month 6 compared with at baseline (57.9±6.0 letters or 20/70 at month 6; P=0.085. At month 6, mean central subfield thickness decreased from 370.4±56.5 to 334.6±65.0 µm (P=0.009. The mean amount of hard exudates increased from 4467.1±2736.1 to 6592.4±2498.3 pixels at month 6 (P=0.022. No serious adverse events occurred.Conclusion: Continuous intravitreal bevacizumab was found to have no benefit in visual acuity and amount of hard exudates, despite the improvement of macular edema at 6 months. Keywords: bevacizumab, diabetic macular edema, hard exudates

  3. A multi-step system for screening and localization of hard exudates in retinal images

    Science.gov (United States)

    Bopardikar, Ajit S.; Bhola, Vishal; Raghavendra, B. S.; Narayanan, Rangavittal

    2012-03-01

    The number of people being affected by Diabetes mellitus worldwide is increasing at an alarming rate. Monitoring of the diabetic condition and its effects on the human body are therefore of great importance. Of particular interest is diabetic retinopathy (DR) which is a result of prolonged, unchecked diabetes and affects the visual system. DR is a leading cause of blindness throughout the world. At any point of time 25 - 44% of people with diabetes are afflicted by DR. Automation of the screening and monitoring process for DR is therefore essential for efficient utilization of healthcare resources and optimizing treatment of the affected individuals. Such automation would use retinal images and detect the presence of specific artifacts such as hard exudates, hemorrhages and soft exudates (that may appear in the image) to gauge the severity of DR. In this paper, we focus on the detection of hard exudates. We propose a two step system that consists of a screening step that classifies retinal images as normal or abnormal based on the presence of hard exudates and a detection stage that localizes these artifacts in an abnormal retinal image. The proposed screening step automatically detects the presence of hard exudates with a high sensitivity and positive predictive value (PPV ). The detection/localization step uses a k-means based clustering approach to localize hard exudates in the retinal image. Suitable feature vectors are chosen based on their ability to isolate hard exudates while minimizing false detections. The algorithm was tested on a benchmark dataset (DIARETDB1) and was seen to provide a superior performance compared to existing methods. The two-step process described in this paper can be embedded in a tele-ophthalmology system to aid with speedy detection and diagnosis of the severity of DR.

  4. Multiscale model of a freeze-thaw process for tree sap exudation.

    Science.gov (United States)

    Graf, Isabell; Ceseri, Maurizio; Stockie, John M

    2015-10-01

    Sap transport in trees has long fascinated scientists, and a vast literature exists on experimental and modelling studies of trees during the growing season when large negative stem pressures are generated by transpiration from leaves. Much less attention has been paid to winter months when trees are largely dormant but nonetheless continue to exhibit interesting flow behaviour. A prime example is sap exudation, which refers to the peculiar ability of sugar maple (Acer saccharum) and related species to generate positive stem pressure while in a leafless state. Experiments demonstrate that ambient temperatures must oscillate about the freezing point before significantly heightened stem pressures are observed, but the precise causes of exudation remain unresolved. The prevailing hypothesis attributes exudation to a physical process combining freeze-thaw and osmosis, which has some support from experimental studies but remains a subject of active debate. We address this knowledge gap by developing the first mathematical model for exudation, while also introducing several essential modifications to this hypothesis. We derive a multiscale model consisting of a nonlinear system of differential equations governing phase change and transport within wood cells, coupled to a suitably homogenized equation for temperature on the macroscale. Numerical simulations yield stem pressures that are consistent with experiments and provide convincing evidence that a purely physical mechanism is capable of capturing exudation. PMID:26400199

  5. CAD scheme for detection of hemorrhages and exudates in ocular fundus images

    Science.gov (United States)

    Hatanaka, Yuji; Nakagawa, Toshiaki; Hayashi, Yoshinori; Mizukusa, Yutaka; Fujita, Akihiro; Kakogawa, Masakatsu; Kawase, Kazuhide; Hara, Takeshi; Fujita, Hiroshi

    2007-03-01

    This paper describes a method for detecting hemorrhages and exudates in ocular fundus images. The detection of hemorrhages and exudates is important in order to diagnose diabetic retinopathy. Diabetic retinopathy is one of the most significant factors contributing to blindness, and early detection and treatment are important. In this study, hemorrhages and exudates were automatically detected in fundus images without using fluorescein angiograms. Subsequently, the blood vessel regions incorrectly detected as hemorrhages were eliminated by first examining the structure of the blood vessels and then evaluating the length-to-width ratio. Finally, the false positives were eliminated by checking the following features extracted from candidate images: the number of pixels, contrast, 13 features calculated from the co-occurrence matrix, two features based on gray-level difference statistics, and two features calculated from the extrema method. The sensitivity of detecting hemorrhages in the fundus images was 85% and that of detecting exudates was 77%. Our fully automated scheme could accurately detect hemorrhages and exudates.

  6. Analytical studies on the gum exudate from Anogeissus leiocarpus

    International Nuclear Information System (INIS)

    Anogeissus leiocarpus gum samples were collected as natural exudate nodules, from three different location. Physicochemical properties of gum samples were studied. results showed significant differences within each location in most parameters studied except refractive index value which was found to be constant in all samples. The effect of location on the properties of gum samples was also studied and the analysis of variance showed insignificant differences (P≤0.05) in all properties studied except in ash content. Inter nodule variations of gum from two different location were studied individually. Results showed significant differences for each parameter studied except for the refractive index value. The properties studied of all gum samples were as follows: 9.2% moisture, 3.4% ash, 0.72% nitrogen, 4.74% protein, -35.5 specific rotation, 1.68 relative viscosity, 4.2 pH, 1.334 refractive index, 14.3 uronic acid, 0.44% reducing sugar, 1336.0 equivalent weight and 0.68% tannin content. UV absorption spectra of gum samples and gum nodules were determined. Cationic composition of gum samples was also determined and the results showed that (Mg) has highest value in all samples studied followed by Fe, Na, K, Ca, Zn and trace amount of Mn, Co, Ni, Cd and Pb. The water holding capacity was found to be 65.5% and emulsifying stability was found to be 1.008. The component sugars of gum were examined by different methods followed by qualitative and quantitative analysis. Analysis of hydrolysate crude gum sample by HPLC show L-rhamnose (6.82), L-arabinose (48.08), D-galactose (11.26) and two unknown oligosaccharides having values (0.22 and 32.61). Some physicochemical properties were studied. Results showed significant differences in nitrogen and protein contents, specific rotation, relative viscosity, equivalent weight and pH of fractions, where as insignificant differences were observed in uronic acid content and refractive index values

  7. Multiscale model of a freeze-thaw process for tree sap exudation

    CERN Document Server

    Graf, Isabell; Stockie, John M

    2015-01-01

    Sap transport in trees has long fascinated scientists, and a vast literature exists on experimental and modelling studies of trees during the growing season when large negative stem pressures are generated by transpiration from leaves. Much less attention has been paid to winter months when trees are largely dormant but nonetheless continue to exhibit interesting flow behaviour. A prime example is sap exudation, which refers to the peculiar ability of sugar maple (Acer saccharum) and related species to generate positive stem pressure while in a leafless state. Experiments demonstrate that ambient temperatures must oscillate about the freezing point before significantly heightened stem pressures are observed, but the precise causes of exudation remain unresolved. The prevailing hypothesis attributes exudation to a physical process combining freeze-thaw and osmosis, which has some support from experimental studies but remains a subject of active debate. We address this knowledge gap by developing the first math...

  8. Two cases of exudative retina detachment and uveitis following H1N1 influenza vaccination

    Institute of Scientific and Technical Information of China (English)

    TAO Yong; CHANG Li-bing; ZHAO Min; LI Xiao-xin

    2011-01-01

    Uveitis was a rare adverse event of vaccination.We met two cases of acute uveitis with exudative retinal detachment following vaccination of H1N1 influenza.Case 1 was a 10-year-old boy who was admitted for bilateral blurred vision at 10 days after vaccination of H1N1 influenza.Vitreous opacity was obvious in both eyes.Broad exudative retinal detachment was observed in the right eye.Case 2 was a 47-year-old female who suffered from an acute high fever at 2 days after the vaccination of H1 N1 influenza.Later,she encountered bilateral headache and decreasing vision.In both eyes,mutton fat keratic precipitates,positive Tyndall phenomenon,congestion of optic disc and exudative retinal detachment were observed.

  9. Clinical performance of a new silver dressing, Contreet Foam, for chronic exuding venous leg ulcers

    DEFF Research Database (Denmark)

    Karlsmark, T; Agerslev, R H; Bendz, S H;

    2003-01-01

    OBJECTIVE: This study aimed to evaluate the safety and performance of a new sustained silver-releasing dressing, Contreet Foam (Coloplast A/S), in the treatment of moderately to highly exuding chronic venous leg ulcers in which healing is delayed due to the presence of bacteria. METHOD: The...... clinical performance of Contreet Foam was studied for four weeks in 25 patients with moderately to highly exuding delayed-healing venous leg ulcers. Healing was assessed on a weekly basis with reference to the wound-bed tissue composition, degree of odour and pain, dressing performance and the dressing......: Contreet Foam was found to be safe and performed well when used in the treatment of delayed-healing chronic venous leg ulcers, combining effective antibacterial properties with excellent exudate management. DECLARATION OF INTEREST: This study was supported by Coloplast A/S, Humlebaek, Denmark....

  10. An association between subclinical familial exudative vitreoretinopathy and rod-cone dystrophy

    Directory of Open Access Journals (Sweden)

    Abdullah Ilhan

    2014-10-01

    Full Text Available A 21-year-old Caucasian man presented with a complaint of nyctalopia. Visual acuity in both eyes was 20/20 and anterior segment biomicroscopy results were unremarkable. Fundoscopy revealed peripheral avascular zones, minimal peripheral retinal exudation from the retinal vessels, peripheral retinal telangiectasias and anastomosis in both eyes, and retinal vascular dragging toward the temporal periphery in both eyes. Full field electroretinography showed that rod responses were almost absent and that cone responses were reduced. Macular optical coherence tomography showed normal structure in both eyes. Vascular changes were attributed to a subclinical form of familial exudative vitreoretinopathy. This was an interesting case due to the association of familial exudative vitreoretinopathy with rod-cone dystrophy.

  11. Improvement of the Hard Exudates Detection Method Used For Computer- Aided Diagnosis of Diabetic Retinopathy

    Directory of Open Access Journals (Sweden)

    Feroui Amel

    2012-05-01

    Full Text Available Diabetic retinopathy is a severe and widely spread eye disease. Early diagnosis and timely treatment of these clinical signs such as hard exudates could efficiently prevent blindness. The presence of exudates within the macular region is a main hallmark of diabetic macular edema and allows its detection with high sensitivity. In this paper, we combine the k-means clustering algorithm and mathematical morphology to detect hard exudates (HEs in retinal images of several diabetic patients. This method is tested on a set of 50 ophthalmologic images with variable brightness, color, and forms of HEs. The algorithm obtained a sensitivity of 95.92%, predictive value of 92.28% and accuracy of 99.70% using a lesion-based criterion.

  12. Automated Root Tracking with "Root System Analyzer"

    Science.gov (United States)

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

    2015-04-01

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

  13. Root canal

    Science.gov (United States)

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

  14. Clinical efficacy of dressings for treatment of heavily exuding chronic wounds

    Directory of Open Access Journals (Sweden)

    Wieg

    2015-06-01

    Full Text Available Cornelia Wiegand, Jörg Tittelbach, Uta-Christina Hipler, Peter Elsner Department of Dermatology, University Hospital Jena, Jena, Germany Abstract: The treatment of chronic ulcers is a complex issue and presents an increasing problem for caregivers everywhere. This is especially true in Germany, where more than 4 million chronic wounds are treated each year. Therapeutic decisions must be patient-centered and reflect wound etiology, localization, and healing status. The practice of using the same wound dressing during the entire healing period is no longer reasonable. Instead, multiple types of dressings may be needed for a single wound over its healing trajectory. Selection of the most appropriate dressing should be based on wound phase, depth, signs of infection, and level of exudate. Moisture balance is critical in wound care; dryness will hamper epithelial cell migration while excessive generation of fluid causes maceration at the wound margins. Hence, exudate management is a key issue in chronic wound therapy, particularly given that exudate from chronic wounds has a composition different from that of acute wound fluid. Several studies have shown that exudates from non-healing wounds contain significantly elevated levels of protease activity, increased formation of free radicals, and abundant amounts of proinflammatory cytokines, while concentrations of growth factors and protease inhibitors are markedly decreased. Application of dressings that remove and sequester excess amounts of wound fluid may not only help in restoring the correct balance of moisture, but also support the wound healing process by preventing tissue deterioration caused by abundant protease activity. Several types of dressings, such as hydrogels, hydrocolloids, alginates, hydrofibers, foams, and superabsorbent dressings, are reviewed here and evaluated with regard to their efficacy for highly exuding wounds. Keywords: chronic wounds, exuding, dressings, clinical efficacy 

  15. Pleural Effusion in Meigs' Syndrome-Transudate or Exudate?: Systematic Review of the Literature.

    Science.gov (United States)

    Krenke, Rafal; Maskey-Warzechowska, Marta; Korczynski, Piotr; Zielinska-Krawczyk, Monika; Klimiuk, Joanna; Chazan, Ryszarda; Light, Richard W

    2015-12-01

    Although Meigs' syndrome is regarded as a well-defined entity, contradictory data on pleural fluid characteristics have been presented, with some papers classifying it as a transudate, whereas others stating that it is an exudate.The aims of the study were: (1) to evaluate pleural fluid characteristics in patients with Meigs' syndrome and (2) to analyze the prevalence of transudative and exudative pleural effusion in relation to the applied definition of the syndrome.We performed a search through medical databases (MEDLINE, EMBASE, SCOPUS, and GOOGLE SCHOLAR) to identify papers on Meigs' syndrome published between 1940 and 2013. Two authors independently reviewed each paper searching for prespecified data: (1) signs and symptoms, (2) tumor characteristics, (3) clinical and laboratory data on ascites, (4) clinical, radiological, and laboratory data on pleural fluid, (5) clinical course after tumor removal. All case reports were reclassified according to a new unequivocal classification of Meigs' syndrome-related entities.A total of 653 papers were initially identified, and 454 articles reporting 541 patients were included in the final analysis. After reclassification according to our case definitions, there were 196, 113, and 108 patients defined as classic Meigs' syndrome, nonclassic Meigs' syndrome, and pseudo-Meigs' syndrome, respectively. Significantly more patients presented with right-sided than left-sided and bilateral pleural effusions (P  3.0 g/dL was applied as a criterion of pleural exudate, 88.8% (80/90) of effusions were classified as exudates. Increasing the cut-off level to 3.5 g/dL resulted in only a modest decrease in the percentage of exudative effusions (81%, 73/90).Surprisingly few reports on Meigs' syndrome present data reliably defining the character of pleural effusion. The available data indicate, however, that the majority of pleural effusions in patients with this entity are exudates. This finding may be a prerequisite for the

  16. Rapid regression of exudative maculopathy in idiopathic retinitis, vasculitis, aneurysms and neuroretinitis syndrome after intravitreal ranibizumab.

    Science.gov (United States)

    Marín-Lambíes, Cristina; Gallego-Pinazo, Roberto; Salom, David; Navarrete, Javier; Díaz-Llopis, Manuel

    2012-05-01

    The idiopathic retinitis, vasculitis, aneurysms and neuroretinitis syndrome is a rare retinal vascular disorder characterized by multiple leaking aneurysmal dilations, retinal vasculitis, neuroretinitis and peripheral vascular ischemia. Visual loss mainly occurs due to the development of retinal neovascularization and/or exudative maculopathy. Although the treatment of choice has not yet been established, retinal photocoagulation seems to be the best option to control the disease and to prevent its progression. Herein, we report a case of idiopathic retinitis, vasculitis, aneurysms and neuroretinitis syndrome with both retinal neovascularization and macular exudation successfully managed with intravitreal ranibizumab (Lucentis(®)) as adjunctive therapy to retinal photocoagulation. PMID:22949913

  17. Antiplasmodial activity of compounds from the surface exudates of Senecio roseiflorus.

    Science.gov (United States)

    Kerubo, Leonidah Omosa; Midiwo, Jacob Ogweno; Derese, Solomon; Langat, Moses K; Akala, Hosea M; Waters, Norman C; Peter, Martin; Heydenreich, Matthias

    2013-02-01

    From the surface exudates of Senecio roseiflorus fourteen known methylated flavonoids and one phenol were isolated and characterized. The structures of these compounds were determined on the basis of their spectroscopic analysis. The surface exudate and the flavonoids isolated showed moderate to good antiplasmodial activity with 5,4'-dihydroxy-7-dimethoxyflavanone having the highest activity against chloroquine-sensitive (D6) and resistant (W2) strains of Plasmodium falciparum, with IC50 values of 3.2 +/- 0.8 and 4.4 +/- 0.01 microg/mL respectively. PMID:23513721

  18. Nitrogen Addition as a Result of Long-Term Root Removal Affects Soil Organic Matter Dynamics

    Science.gov (United States)

    Crow, S. E.; Lajtha, K.

    2004-12-01

    A long-term field litter manipulation site was established in a mature coniferous forest stand at the H.J. Andrews Experimental Forest, OR, USA in 1997 in order to address how detrital inputs influence soil organic matter formation and accumulation. Soils at this site are Andisols and are characterized by high carbon (C) and low nitrogen (N) contents, due largely to the legacy of woody debris and extremely low atmospheric N deposition. Detrital treatments include trenching to remove roots, doubling wood and needle litter, and removing aboveground litter. In order to determine whether five years of detrital manipulation had altered organic matter quantity and lability at this site, soil from the top 0-5 cm of the A horizon was density fractionated to separate the labile light fraction (LF) from the more recalcitrant mineral soil in the heavy fraction (HF). Both density fractions and whole soils were incubated for one year in chambers designed such that repeated measurements of soil respiration and leachate chemistry could be made. Trenching resulted in the removal of labile root inputs from root exudates and turnover of fine roots and active mycorrhizal communities as well as an increase of available N by removing plant uptake. Since 1999, soil solution chemistry from tension lysimeters has shown greater total N and dissolved organic nitrogen (DON) flux and less dissolved organic carbon (DOC) flux to stream flow in the trenched plots relative to the other detrital treatments. C/N ratio and C content of both light and heavy fractions from the trenched plots were greater than other detrital treatments. In the lab incubation, over the course of a year C mineralization from these soils was suppressed. Cumulative DOC losses and CO2 efflux both were significantly less in soils from trenched plots than in other detrital treatments including controls. After day 150 of the incubation, leachates from the HF of plots with trenched treatments had a DOC/DON ratio significantly

  19. Zinc-resistance gene CzrC identified in methicillin-resistant Staphylococcus hyicus isolated from pigs with exudative epidermitis.

    Science.gov (United States)

    Slifierz, Mackenzie J; Park, Jeonghwa; Friendship, Robert M; Weese, J Scott

    2014-05-01

    Methicillin-resistant Staphylococcus hyicus (MRSH) was investigated for czrC, a gene conferring zinc-resistance. The czrC gene was identified in 50% (14/28) of MRSH isolates, representing 14 pigs with exudative epidermitis from 8 farms. Newly weaned pigs, which are particularly susceptible to exudative epidermitis, are commonly fed high levels of zinc oxide. PMID:24790238

  20. Mevalonate-derived quinonemethide triterpenoid from in vitro roots of Peritassa laevigata and their localization in root tissue by MALDI imaging

    Science.gov (United States)

    Pina, Edieidia S.; Silva, Denise B.; Teixeira, Simone P.; Coppede, Juliana S.; Furlan, Maysa; França, Suzelei C.; Lopes, Norberto P.; Pereira, Ana Maria S.; Lopes, Adriana A.

    2016-03-01

    Biosynthetic investigation of quinonemethide triterpenoid 22β-hydroxy-maytenin (2) from in vitro root cultures of Peritassa laevigata (Celastraceae) was conducted using 13C-precursor. The mevalonate pathway in P. laevigata is responsible for the synthesis of the quinonemethide triterpenoid scaffold. Moreover, anatomical analysis of P. laevigata roots cultured in vitro and in situ showed the presence of 22β-hydroxy-maytenin (2) and maytenin (1) in the tissues from transverse or longitudinal sections with an intense orange color. MALDI-MS imaging confirmed the distribution of (2) and (1) in the more distal portions of the root cap, the outer cell layers, and near the vascular cylinder of P. laevigata in vitro roots suggesting a role in plant defense against infection by microorganisms as well as in the root exudation processes.

  1. Rhizosphere wettability decreases with root age: A problem or a strategy to increase water uptake of young roots?

    Directory of Open Access Journals (Sweden)

    Andrea eCarminati

    2013-08-01

    Full Text Available As plant roots take up water and the soil dries, water depletion is expected to occur in the vicinity of roots, the so called rhizosphere. However, recent experiments showed that the rhizosphere of lupines was wetter than the bulk soil during the drying period. Surprisingly, the rhizosphere remained temporarily dry after irrigation. Such water dynamics in the rhizosphere can be explained by the drying/wetting dynamics of mucilage exuded by roots. The capacity of mucilage to hold large volumes of water at negative water potential may favor root water uptake. However, mucilage hydrophobicity after drying may temporarily limit the local water uptake after irrigation. The effects of such rhizosphere dynamics are not yet understood. In particular, it is not known how the rhizosphere dynamics vary along roots and as a function of soil water content. My hypothesis was that the rewetting rate of the rhizosphere is primarily function of root age. Neutron radiography was used to monitor how the rhizosphere water dynamics vary along the root systems of lupines during drying/wetting cycles of different duration. The radiographs showed a fast and almost immediate rewetting of the rhizosphere of the distal root segments, in contrast to a slow rewetting of the rhizosphere of the proximal segments. The rewetting rate of the rhizosphere was not function of the water content before irrigation, but it was function of time. It is concluded that rhizosphere hydrophobicity is not uniform along roots, but it covers only the older and proximal root segments, while the young root segments are hydraulically well connected to the soil. I included these rhizosphere dynamics in a microscopic model of root water uptake. In the model, the relation between water content and water potential in the rhizosphere is not unique and it varies over time, and the rewetting rate of the rhizosphere decreases with time. The rhisosphere variability seems an optimal adaptation strategy to

  2. Study on the antibiosis of exudate JK-91-b against rice sheath blight (SHB)

    Institute of Scientific and Technical Information of China (English)

    CHENZhiyi; YINShangzhi; GAOXianting

    1994-01-01

    Antagonistic bacterial strain 91-b possessed stronger antagonistic ability against SHB infection. The control effects of the bacterization against SHB were 58.1% in greenhouse and 45.1% in paddy. The effect of antibiosis JK-91-b exudated by strain 91-b was studied in the present research.

  3. Solid phase extraction and metabolic profiling of exudates from living copepods

    DEFF Research Database (Denmark)

    Selander, Erik; Heuschele, Jan; Nylund, Göran M.; Pohnert, Georg; Pavia, Henrik; Bjærke, Oda; Pender-Healy, Larisa A.; Tiselius, Peter; Kiørboe, Thomas

    2016-01-01

    Copepods are ubiquitous in aquatic habitats. They exude bioactive compounds that mediate mate finding or induce defensive traits in prey organisms. However, little is known about the chemical nature of the copepod exometabolome that contributes to the chemical landscape in pelagic habitats. Here ...

  4. [Role of herpes simplex virus in the development of exudative erythema multiforme].

    Science.gov (United States)

    Samgin, M A; Ivanov, O L; Kuzheleva, S A; Biriukov, A V; L'vov, N D

    1990-03-01

    The paper presents analysis of current knowledge on etiology and immunopathogenesis of multiform exudative erythema (MEE). Among a variety of pathogenetic actions of herpes simplex on immune system are those relevant to MEE onset. These variants are dealt with in detail. The view on MEE as resultant from herpes simplex infection promises appearance of new prospective modes of etiotropic therapy. PMID:2370760

  5. A novel method for retinal exudate segmentation using signal separation algorithm.

    Science.gov (United States)

    Imani, Elaheh; Pourreza, Hamid-Reza

    2016-09-01

    Diabetic retinopathy is one of the major causes of blindness in the world. Early diagnosis of this disease is vital to the prevention of visual loss. The analysis of retinal lesions such as exudates, microaneurysms and hemorrhages is a prerequisite to detect diabetic disorders such as diabetic retinopathy and macular edema in fundus images. This paper presents an automatic method for the detection of retinal exudates. The novelty of this method lies in the use of Morphological Component Analysis (MCA) algorithm to separate lesions from normal retinal structures to facilitate the detection process. In the first stage, vessels are separated from lesions using the MCA algorithm with appropriate dictionaries. Then, the lesion part of retinal image is prepared for the detection of exudate regions. The final exudate map is created using dynamic thresholding and mathematical morphologies. Performance of the proposed method is measured on the three publicly available DiaretDB, HEI-MED and e-ophtha datasets. Accordingly, the AUC of 0.961 and 0.948 and 0.937 is achieved respectively, which are greater than most of the state-of-the-art methods. PMID:27393810

  6. Compositional analysis and rheological characterization of gum tragacanth exudates from six species of Iranian Astragalus

    DEFF Research Database (Denmark)

    Balaghi, Sima; Mohammadifar, Mohammad Amin; Zargaraan, Azizollaah;

    2011-01-01

    The sugar composition and viscoelastic behaviour of Iranian gum tragacanth exuded by six species of Astragalus was investigated at a concentration of 1.3% and varying ionic strength using a controlled shear-rate rheometer. Compositional analysis of the six species of gum tragacanth by high...

  7. Influence of aluminum on growth, mineral nutrition and organic acid exudation of rambutan (Nephelium lappaceum)

    Science.gov (United States)

    A randomized complete block design experiment with six aluminum (Al) concentrations was carried out to evaluate the effect of aluminum on nutrient content, plant growth, dry matter production and Al-induced organic acid exudation in rambutan (Nephelium lappaceum). One rambutan cultivar was grown in...

  8. Lactoferrin, myeloperoxidase, lysozyme and eosinophil cationic protein in exudate in delayed type hypersensitivity

    DEFF Research Database (Denmark)

    Lerche, A; Bisgaard, H; Christensen, J D; Venge, P; Dahl, R; Søndergaard, J

    1988-01-01

    A skin window technique was used to study the morphology of leucocytes in upper dermis and exudate during nickel challenge in patients with contact allergy to nickel. Contact allergic patients and healthy volunteers tested with a skin widow without addition of nickel to the chamber medium served as...

  9. Characterisation and molecular association of Nigerian and Sudanese Acacia gum exudates

    Science.gov (United States)

    The chemical and physicochemical characteristics of gum exudate samples harvested from mature trees of Acacia senegal at two specific locations in Nigeria have been investigated together with gum samples harvested from Acacia senegal and Acacia seyal originating from Sudan. The monosaccharide sugar ...

  10. Use of a hydrocapillary dressing in the management of highly exuding ulcers: a comparative study

    DEFF Research Database (Denmark)

    Norkus, A; Dargis, V; Thomsen, J K;

    2005-01-01

    was conducted on 97 patients with an ankle brachial pressure index > or = 0.8 and a highly exuding leg ulcer. Ulcer duration was at least four weeks.Treatment continued until healing or for a maximum of 12 months. RESULTS: There was no statistically significant difference in healing time or wound area reduction...

  11. Clinical outcomes of the treatment of exudative age-related macular degeneration with Pegaptanib

    Directory of Open Access Journals (Sweden)

    M. Burova

    2013-02-01

    Full Text Available ABSTRACT Purpose. To evaluate the results of intravitreal use of Pegaptanib in patients with exudative age-related macular degeneration (AMD. Material end methods. Our study includes 77 patients with exudative AMD, who received 9 injections of Pegaptanib 0.3mg with 6-weeks intervals between them. So the primary treatment lasted one year. During and after the treatment these patients underwent fluorescent angiography (FAG, optical coherence tomography (OCT, fundus photography and best corrected visual acuity (BCVA examination. According to the results of these examinations a decision about a further treatment, whether it was necessary, was taken. Results. By the end of our 2-year study 38 patients after therapy with Pegaptanib had complete obliteration of the choroidal neovascularization (CNV, 19 patients were switched to Ranibizumab, one patient underwent photodynamic therapy with Visudyne, 14 patients had severe progression of AMD, when there was no sense in further treatment, 2 patients dropped out the study because of cerebral insult, 3 patients refused of any further treatment, in spite of persisting exudative activity of the CNV after the primary treatment. Conclusion. Intravitreal аpplication of Pegaptanib is a relatively effective treatment option of exudative AMD as BCVA was stabilized or improved in 55.8% of patients, macular edema decreased in 67.5% of patients and neovascular membrane was obliterated in 49.35% of patients.

  12. Decision support system for the detection and grading of hard exudates from color fundus photographs

    Science.gov (United States)

    Jaafar, Hussain F.; Nandi, Asoke K.; Al-Nuaimy, Waleed

    2011-11-01

    Diabetic retinopathy is a major cause of blindness, and its earliest signs include damage to the blood vessels and the formation of lesions in the retina. Automated detection and grading of hard exudates from the color fundus image is a critical step in the automated screening system for diabetic retinopathy. We propose novel methods for the detection and grading of hard exudates and the main retinal structures. For exudate detection, a novel approach based on coarse-to-fine strategy and a new image-splitting method are proposed with overall sensitivity of 93.2% and positive predictive value of 83.7% at the pixel level. The average sensitivity of the blood vessel detection is 85%, and the success rate of fovea localization is 100%. For exudate grading, a polar fovea coordinate system is adopted in accordance with medical criteria. Because of its competitive performance and ability to deal efficiently with images of variable quality, the proposed technique offers promising and efficient performance as part of an automated screening system for diabetic retinopathy.

  13. Massive Lumbosacral Subcutaneous Exudate After Surgical Treatment of a Large Lipomyelocele

    Science.gov (United States)

    Gao, Jun; Kong, Xiangyi; Yang, Yi; Ma, Wenbin; Wang, Renzhi; Li, Yongning

    2015-01-01

    Abstract Lipomyelocele is an uncommon type of lipoma that occurs with spina bifida. We present the clinical course and therapeutic process of a female who underwent resection of a lipomyelocele and developed a massive lumbosacral subcutaneous exudate postoperatively. The therapeutic process is described in detail, and a review of the relevant literature on lipomyelocele is presented. A 23-year-old woman presented to our institution complaining of a large lumbosacral subcutaneous mass. She underwent surgical resection of the mass and untethering of the spinal cord under intraoperative neurophysiologic monitoring. A massive lumbosacral subcutaneous exudate developed postoperatively. After excluding cerebrospinal fluid (CSF) leakage, we placed a suction drain. Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the editor of this journal. Because of this, there is no need to conduct special ethic review and the ethical approval is not necessary. Postoperative pathologic examination confirmed the diagnosis of lipomyelocele. Continuation of the negative-pressure drain for 1 week yielded >1000 mL of fluid. The patient recovered well and developed no further subcutaneous exudate. In a patient with massive lumbosacral subcutaneous exudate after surgical treatment of a large lipomyelocele, continuous negative-pressure drainage can be an effective treatment method after excluding CSF leakage. PMID:26426667

  14. Locally Finite Root Supersystems

    OpenAIRE

    YOUSOFZADEH, Malihe

    2013-01-01

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

  15. Macromolecular composition of phloem exudate from white lupin (Lupinus albus L.

    Directory of Open Access Journals (Sweden)

    Mann Anthea J

    2011-02-01

    Full Text Available Abstract Background Members of the legume genus Lupinus exude phloem 'spontaneously' from incisions made to the vasculature. This feature was exploited to document macromolecules present in exudate of white lupin (Lupinus albus [L.] cv Kiev mutant, in particular to identify proteins and RNA molecules, including microRNA (miRNA. Results Proteomic analysis tentatively identified 86 proteins from 130 spots collected from 2D gels analysed by partial amino acid sequence determination using MS/MS. Analysis of a cDNA library constructed from exudate identified 609 unique transcripts. Both proteins and transcripts were classified into functional groups. The largest group of proteins comprised those involved in metabolism (24%, followed by protein modification/turnover (9%, redox regulation (8%, cell structural components (6%, stress and defence response (6% with fewer in other groups. More prominent proteins were cyclophilin, ubiquitin, a glycine-rich RNA-binding protein, a group of proteins that comprise a glutathione/ascorbate-based mechanism to scavenge oxygen radicals, enzymes of glycolysis and other metabolism including methionine and ethylene synthesis. Potential signalling macromolecules such as transcripts encoding proteins mediating calcium level and the Flowering locus T (FT protein were also identified. From around 330 small RNA clones (18-25 nt 12 were identified as probable miRNAs by homology with those from other species. miRNA composition of exudate varied with site of collection (e.g. upward versus downward translocation streams and nutrition (e.g. phosphorus level. Conclusions This is the first inventory of macromolecule composition of phloem exudate from a species in the Fabaceae, providing a basis to identify systemic signalling macromolecules with potential roles in regulating development, growth and stress response of legumes.

  16. Rhizosphere biophysics and root water uptake

    Science.gov (United States)

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

    2016-04-01

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

  17. Identification and localization of bioactive naphthoquinones in the roots and rhizosphere of Paterson's curse (Echium plantagineum), a noxious invader.

    Science.gov (United States)

    Zhu, Xiaocheng; Skoneczny, Dominik; Weidenhamer, Jeffrey D; Mwendwa, James M; Weston, Paul A; Gurr, Geoff M; Callaway, Ragan M; Weston, Leslie A

    2016-06-01

    Bioactive plant secondary products are frequently the drivers of complex rhizosphere interactions, including those with other plants, herbivores and microbiota. These chemically diverse molecules typically accumulate in a highly regulated manner in specialized plant tissues and organelles. We studied the production and localization of bioactive naphthoquinones (NQs) in the roots of Echium plantagineum, an invasive endemic weed in Australia. Roots of E. plantagineum produced red-coloured NQs in the periderm of primary and secondary roots, while seedling root hairs exuded NQs in copious quantities. Confocal imaging and microspectrofluorimetry confirmed that bioactive NQs were deposited in the outer layer of periderm cells in mature roots, resulting in red colouration. Intracellular examination revealed that periderm cells contained numerous small red vesicles for storage and intracellular transport of shikonins, followed by subsequent extracellular deposition. Periderm and root hair extracts of field- and phytotron-grown plants were analysed by UHPLC/Q-ToF MS (ultra high pressure liquid chromatography coupled to quadrupole time of flight mass spectrometry) and contained more than nine individual NQs, with dimethylacrylshikonin, and phytotoxic shikonin, deoxyshikonin and acetylshikonin predominating. In seedlings, shikonins were first found 48h following germination in the root-hypocotyl junction, as well as in root hair exudates. In contrast, the root cortices of both seedling and mature root tissues were devoid of NQs. SPRE (solid phase root zone extraction) microprobes strategically placed in soil surrounding living E. plantagineum plants successfully extracted significant levels of bioactive shikonins from living roots, rhizosphere and bulk soil surrounding roots. These findings suggest important roles for accumulation of shikonins in the root periderm and subsequent rhizodeposition in plant defence, interference, and invasion success. PMID:27194735

  18. Alterações morfológicas no sistema radicular do milho induzidas por fungos micorrízicos e fósforo Morphological alterations on root system of maize induced by mycorrhizal fungi and phosphorus

    Directory of Open Access Journals (Sweden)

    Wellington Bressan

    2002-04-01

    Full Text Available O objetivo deste trabalho, conduzido em casa de vegetação, foi avaliar os efeitos da inoculação de fungos micorrízicos arbusculares (Glomus etunicatum e Glomus clarum e da adição de níveis de P (0, 50, 100 e 200 mg/kg de solo sobre a morfologia do sistema radicular do milho (Zea mays L., cultivar BR 201, e a concentração de P na planta, em duas épocas de colheita (18 e 104 dias após semeadura em solo Latossolo Vermelho-Escuro distrófico desinfestado com Bromex. O experimento foi realizado na Embrapa-Centro Nacional de Pesquisa de Milho e Sorgo, Sete Lagoas, MG. A inoculação de fungos micorrízicos aumentou o peso das raízes secas, o número de raízes laterais primárias e secundárias, e o teor de P na planta, porém reduziu a relação peso das raízes secas/peso da parte aérea seca e o número de pêlos radiculares. Esses efeitos foram dependentes das doses de P aplicadas ao solo e da espécie de fungo micorrízico. O peso das raízes secas das plantas micorrizadas mostrou correlação significativa (PThe objective of this research, carried out under greenhouse conditions was to evaluate the effect of mycorrhizal fungi (Glomus etunicatum and Glomus clarum inoculation and P levels (0, 50, 100 e 200 mg/kg of soil on maize (Zea mays L. root system morphology, cultivar BR 201, and P plant concentration in two harvest period (18 and 104 days after sowing in disinfested dystrophic Dark-Red Latosol. The experiment was carried out under greenhouse conditions at Embrapa-Centro Nacional de Pesquisa de Milho e Sorgo, in Sete Lagoas, Minas Gerais, Brazil. Inoculation with mycorrhizal fungi increased root dry weight, number of first and second order lateral roots and P concentration in the plant, but decreased root/shoot dry weight ratio and number of root hairs. These effects were affected by P concentration in the soil and by mycorrhizal fungi species. Root dry weight of inoculated plants showed significative (P<=0.05 correlation to

  19. Root Responses to Boron Deficiency Mediated by Ethylene

    OpenAIRE

    González-Fontes, Agustín; Herrera-Rodríguez, M. B.; Martín-Rejano, Esperanza M.; Navarro-Gochicoa, M. T.; Rexach, Jesús; Camacho-Cristóbal, Juan J.

    2016-01-01

    Low boron (B) supply alters the architecture of the root system in Arabidopsis thaliana seedlings, leading to a reduction in the primary root growth and an increase in the length and number of root hairs. At short-term (hours), B deficiency causes a decrease in the cell elongation of the primary root, resulting in a lower growth. Experimental approaches using ethylene insensitive Arabidopsis mutants, inhibitors of ethylene response, and GUS reporter lines suggest that ethylene is involved in ...

  20. BT TOXIN IS RELEASED IN ROOT EXUDATES FROM 12 TRANSGENIC CORN HYBRIDS REPRESENTING THREE TRANSFORMATION EVENTS. (R826107)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  1. Determination of Organic Acids in Root Exudates by High Performance Liquid Chromatography:Ⅱ.Influence of Several Testing COnditions

    Institute of Scientific and Technical Information of China (English)

    SHENJIANBO; ZHANGFUSUO; 等

    1999-01-01

    Effects of column temperature and flow rate on separation of organic acids were studied by determining nine low-molecular-weight organic acids on reversed-phase C18 column using high performace liquid chromatography(HPLC) with a wavelength of UV(ultraviolet)214 nm and a mobile phase of 18 mmol L-1 KH2PO4 buffer solution (pH2.1).The thermal stabiltiy of organic acids was determined by comparing the recoveries of organic acids in different temperature treatments.The relationships between column temperature,flow rate or solvent pH and retention time were analyzed.At low solvent pH,separatioin efficiency of organic acids was increased by raising the flow rate of the solvent because of lowering the retention time or organic acids.High column temperature was unfavorable for the separation of organic acids.The separating effect can be enhanced through reducing column temperature in organic acid determination due to increasing retention time.High thermal stability of organic acids with low concentrations was observed at temperature of 40℃-45℃,Sensitivity and separation effect of organic acid determination by HPLC were clearly improved by a combination of raising flow rate and lowering column temperature at low solvent pH.

  2. Isolation and identification of Desmodium root exudates from drought tolerant species used as intercrops against Striga hermonthica

    OpenAIRE

    Hooper, A.M.; Caulfield, J.C.; Hao, B; Pickett, J.A.; Midega, C.A.O.; Khan, Z.R.

    2015-01-01

    Plants from the genus Desmodium, in particular D. uncinatum, are used on sub-Saharan small-holder farms as intercrops to inhibit parasitism of cereal crops by Striga hermonthica and Striga asiatica via an allelopathic mechanism. The search for Desmodium species which are adapted to more arid conditions, and which show resilience to increased drought stress, previously identified D. intortum, D. incanum and D. ramosissimum as potential drought tolerant intercrops. Their potential as intercrops...

  3. Extraction and identification of ginseng root exudates%人参根系分泌物的提取及鉴定

    Institute of Scientific and Technical Information of China (English)

    张爱华; 彭洪利; 雷锋杰; 张连学

    2014-01-01

    [目的]鉴定人参根系分泌物中的化学物质,为研究人参化感作用的发生及其连作障碍提供科学依据.[方法]采用灭菌复合基质复配无土栽培人参,对人参根系分泌物进行原位收集,依次用蒸馏水和乙醇提取人参根系分泌物,合并后用有机溶剂萃取,获得水层及有机相石油醚层和乙酸乙酯层,用HPLC和GC-MS检测水层和2层有机相的物质组成.[结果]人参根系分泌物石油醚层中含有1,3-二氧戊环,4-甲基,4-乙基-2-十五烷、乙基柠檬酸、棕榈酸乙酯和二十五烷等20种化合物,其中,烷烃类物质占46.56%,有机酸酯类物质占22.75%,酚酸类物质占13.78%,烷烃衍生物占3.59%,吡喃类物质占5.39%.乙酸乙酯层中含有丁基柠檬酸、邻苯甲二酸二丁酯和单(2-乙基己基)邻苯二甲酸酯等9种化合物,其中,烷烃类物质占22.77%,有机酸酯类物质占63.71%,酚酸类物质占13.52%.人参根系分泌物水层中含有微量人参皂苷.[结论]采用无土栽培基质可避免人参栽培中微生物的干扰,能很好地培养收集人参根系分泌物,人参根系分泌物中含有人参皂苷及烷烃类物质、有机酸酯类物质和酚酸类物质.

  4. Plasma membrane H+-ATPase-dependent citrate exudation from cluster roots of phosphate-deficient white lupin

    DEFF Research Database (Denmark)

    Tomasi, Nicola; Kretzschmar, Tobias; Espen, Luca;

    2009-01-01

    increased transiently and reached a maximum after 5 h. This effect was accompanied by a strong acidification of the external medium and alkalinization of the cytosol, as evidenced by in vivo nuclear magnetic resonance (NMR) analysis. Fusicoccin, nuclear magnetic resonance (NMR) analysis. Fusicoccin...

  5. Plant growth inhibiting flavonoids in exudate of Cistus ladanifer and in associated soils.

    Science.gov (United States)

    Chaves, N; Sosa, T; Escudero, J C

    2001-03-01

    Of the aglycone flavonoids identified in the exudate of cistus ladanifer, two, the flavone apigenin-4'-(O)-methyl and the flavonol kaempferol-3,7-di(O)-methyl inhibit development of the seedlings of Rumex crispus at 0.5 and 1 mM. Additive effects were observed between the major flavonols of the exudate kaempferol-3-(O)-methyl and kaempferol-3,7-di-(O)-methyl in inhibiting the size of the cotyledons and delaying the germination and cotyledon emergence. The presence of apigenin-4'-(O)-methyl, kaempferol-3,7-di-(O)-methyl, and kaempferol-3-(O)-methyl was detected in the soils associated with C. ladanifer during the summer and autumn months. That these compounds are present in the soil and are not restricted to the leaves provides support for the hypothesis that C. ladanifer has allelopathic potential. PMID:11441450

  6. Multiscale model of a freeze-thaw process for tree sap exudation

    OpenAIRE

    Graf, Isabell; Ceseri, Maurizio; Stockie, John M.

    2015-01-01

    Sap transport in trees has long fascinated scientists, and a vast literature exists on experimental and modelling studies of trees during the growing season when large negative stem pressures are generated by transpiration from leaves. Much less attention has been paid to winter months when trees are largely dormant but nonetheless continue to exhibit interesting flow behaviour. A prime example is sap exudation, which refers to the peculiar ability of sugar maple (Acer saccharum) and related ...

  7. A case of von Hippel-Lindau disease with exudative maculopathy

    OpenAIRE

    Ba′arah, Basel T.

    2009-01-01

    Von Hippel-Lindau (VHL) disease is a rare multisystem familial tumor syndrome of autosomal dominant inheritance. Hallmark lesions include retinal, cerebellum and spinal cord hemangioblastomas, renal cell carcinomas, adrenal pheochromocytomas, angiomatous or cystic lesions of the kidneys, pancreas, and epididymis. We report a case of VHL disease in a 26-year-old patient who presented with exudative macular edema. Ocular and systemic studies revealed the presence of retinal and central nervous ...

  8. Comparative effects of argon green and krypton red laser photocoagulation for patients with diabetic exudative maculopathy.

    OpenAIRE

    Khairallah, M; Brahim, R; Allagui, M.; Chachia, N

    1996-01-01

    AIMS/BACKGROUND: Focal treatment of diabetic macular oedema is usually done using a haemoglobin absorbing wave-length, such as argon green laser. This study aimed to compare photocoagulation with argon green (514 nm) and krypton red (647 nm), which is poorly absorbed by haemoglobin, in the focal treatment of patients with diabetic exudative maculopathy. METHODS: A total of 151 eyes of 78 outpatients were assigned randomly to receive either argon green (n = 79) or krypton red (n = 72) laser tr...

  9. Rapid Regression of Exudative Maculopathy in Idiopathic Retinitis, Vasculitis, Aneurysms and Neuroretinitis Syndrome after Intravitreal Ranibizumab

    OpenAIRE

    Marín-Lambíes, Cristina; Gallego-Pinazo, Roberto; Salom, David; Navarrete, Javier; Díaz-Llopis, Manuel

    2012-01-01

    The idiopathic retinitis, vasculitis, aneurysms and neuroretinitis syndrome is a rare retinal vascular disorder characterized by multiple leaking aneurysmal dilations, retinal vasculitis, neuroretinitis and peripheral vascular ischemia. Visual loss mainly occurs due to the development of retinal neovascularization and/or exudative maculopathy. Although the treatment of choice has not yet been established, retinal photocoagulation seems to be the best option to control the disease and to preve...

  10. Roles of antibody and complement in the bactericidal activity of mouse peritoneal exudate neutrophils.

    OpenAIRE

    Hart, P. H.; Spencer, L. K.; Hill, N L; McDonald, P J; Finlay-Jones, J. J.

    1987-01-01

    The contributions of complement and antibody to phagocytosis and, as a separate process, intracellular killing of Proteus mirabilis, were investigated using mouse peritoneal exudate neutrophils. Phagocytosis of P. mirabilis was promoted by both immune mouse (IMS) and normal mouse (NMS) sera. Opsonization by IMS promoted significantly greater phagocytosis than did NMS, as did NMS compared with heated IMS (HIMS). The ability of NMS to opsonize P. mirabilis for both phagocytosis and phagocytic k...

  11. Differing Organic Acid Exudation Pattern Explains Calcifuge and Acidifuge Behaviour of Plants

    OpenAIRE

    Tyler, Germund; Ström, Lena

    1995-01-01

    Many vascular plant species are unable to colonize calcareous sites. Thus, the floristic composition of adjacent limestone and acid silicate soils differs greatly. The inability of calcifuge plants to establish in limestone sites seems related to a low capacity of such plants to solubilize and absorb Fe or phosphate from these soils. Until now, mechanisms regulating this differing ability of plants to colonize limestone sites have not been elucidated. We propose that contrasting exudation of ...

  12. An association between subclinical familial exudative vitreoretinopathy and rod-cone dystrophy

    OpenAIRE

    Abdullah Ilhan; Umit Yolcu; Fatih Cakir Gundogan; Fahrettin Akay

    2014-01-01

    A 21-year-old Caucasian man presented with a complaint of nyctalopia. Visual acuity in both eyes was 20/20 and anterior segment biomicroscopy results were unremarkable. Fundoscopy revealed peripheral avascular zones, minimal peripheral retinal exudation from the retinal vessels, peripheral retinal telangiectasias and anastomosis in both eyes, and retinal vascular dragging toward the temporal periphery in both eyes. Full field electroretinography showed that rod responses were almost absent an...

  13. Antigenic evidence for host origin of exudative fluids in lesions of Treponema pallidum-infected rabbits.

    OpenAIRE

    Wos, S M; Wicher, K.

    1985-01-01

    Mucoid fluid accumulating within syphilitic lesions has been considered to be of Treponema pallidum origin. To test this assumption, we examined testicular exudative fluids from T. pallidum-infected rabbits for the presence of T. pallidum antigens by various sensitive immunochemical methods, including Western blot analysis. Antigenic analysis of these fluids revealed host components but not treponemal antigens. Prolonged immunization of rabbits, guinea pigs, and a goat with this material in c...

  14. Effect of Bark Extract and Gum Exudate of Commiphora Caudata on Aspirin Induced Ulcer in Rats

    OpenAIRE

    R Nanthakumar; Ambrose S Stephen; E Sriram; Babu, G.; K Chitra; C Uma maheswara Reddy

    2009-01-01

    Commiphora caudata is used in Indian folk medicine as an antiulcerogenic agent. Despite of its promising use, there has been no scientific report present regarding its antiulcer activity. Therefore, this study was designed to evaluate the antiulcer activity of bark extract and gum exudate of commiphora caudata on aspirin induced ulcer in rats. Acute toxicity study was performed and 200 mg/kg was selected as an effective dose. Four groups of Albino Swiss rats were included in this study. Aspir...

  15. The role of prophylactic ibuprofen and N-acetylcysteine on the level of cytokines in periapical exudates and the post-treatment pain

    Directory of Open Access Journals (Sweden)

    Ehsani Maryam

    2012-09-01

    Full Text Available Abstract Background Periapical lesions are inflammatory diseases that result in periapical bone destruction because of host defensive–microbial disturbances. Objective To evaluate the role of prophylactic ibuprofen and N-acetylcysteine (NAC on the levels of tumor necrosis factor alpha (TNF- α, interleukin- 6(IL-6 and IL-17 and post-treatment pain level in chronic periapical lesions. Materials and methods Eighty patients with chronic apical lesions less than 1 cm were randomly assigned to receive NAC tablets (400 mg, ibuprofen tablets (400 mg, NAC (400 mg/ibuprofen (200 mg combination and placebo 90 minutes prior to sampling. Periapical exudates were collected from root canals. TNF- α, IL-6 and IL-17 levels were determined by ELISA and post-treatment pain was assessed using a visual analog scale (VAS. Results There was a significant difference in IL-6 level between ibuprofen group and placebo (p = 0.019. Significant difference in IL-17 level was observed between NAC/ibuprofen combination group and placebo (p = 0.043. Four hours after treatment, a significant difference was observed in VAS pain score between ibuprofen group and placebo (p = 0.017. Eight hours post-treatment, VAS pain score for NAC group was statistically lower than placebo group (p = 0.033. After 12 hours VAS pain score showed a significant decrease in NAC group compared to placebo (p = 0.049. Conclusion The prophylactic ibuprofen and NAC failed to clearly reflect their effect on cytokines levels in exudates of chronic periapical lesions. On the other hand it seems that NAC can be a substitute for ibuprofen in the management of post endodontic pain.

  16. The Role of Prophylactic Ibuprofen and N-Acetylcysteine on the Level of Cytokines in Periapical Exudates and the Post-Treatment Pain

    Directory of Open Access Journals (Sweden)

    Seyyed Mohsen Aghajanpour Mir

    2012-09-01

    Full Text Available Background Periapical lesions are inflammatory diseases that result in periapical bone destruction because of host defensive-microbial disturbances. Objective:To evaluate the role of prophylactic ibuprofen and N-acetylcysteine (NAC on the levels of tumor necrosis factor alpha (TNF- alpha, interleukin- 6(IL-6 and IL-17 and post-treatment pain level in chronic periapical lesions. Materials and methods Eighty patients with chronic apical lesions less than 1 cm were randomly assigned to receive NAC tablets (400 mg, ibuprofen tablets (400 mg, NAC (400 mg/ibuprofen (200 mg combination and placebo 90 minutes prior to sampling. Periapical exudates were collected from root canals. TNF- alpha, IL-6 and IL-17 levels were determined by ELISA and posttreatment pain was assessed using a visual analog scale (VAS. Results:There was a significant difference in IL-6 level between ibuprofen group and placebo (p = 0.019. Significant difference in IL-17 level was observed between NAC/ibuprofen combination group and placebo (p = 0.043. Four hours after treatment, a significant difference was observed in VAS pain score between ibuprofen group and placebo (p = 0.017. Eight hours post-treatment, VAS pain score for NAC group was statistically lower than placebo group (p = 0.033. After 12 hours VAS pain score showed a significant decrease in NAC group compared to placebo (p = 0.049. Conclusion:The prophylactic ibuprofen and NAC failed to clearly reflect their effect on cytokines levels in exudates of chronic periapical lesions. On the other hand it seems that NAC can be a substitute for ibuprofen in the management of post endodontic pain

  17. Serum VEGF and CFH in Exudative Age-Related Macular Degeneration

    Science.gov (United States)

    Haas, Paulina; Steindl, Kerstin; Aggermann, Tina; Schmid-Kubista, Katharina; Krugluger, Walter; Hageman, Gregory S.; Binder, Susanne

    2014-01-01

    Purpose To determine serum vascular endothelial growth factor 165 (VEGF165) levels and the association of the complement factor H gene (CFH) Y402H polymorphism in patients with exudative age-related macular degeneration (AMD) in comparison to unaffected control subjects. Methods Sixty-six AMD patients and 66 healthy age- and gender-matched controls were included in this case-control study. The serum VEGF165 was assayed by ELISA (R&D). Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism analysis. Chisquared tests were used regarding the polymorphism, a t-test regarding the VEGF-levels. Results Levels of serum VEGF165 were similar in both groups (p-value = 0.2112). Genotype frequency differed significantly between patients with exudative AMD and the healthy control group (p = 0.003136). The serum VEGF165 levels were similar irrespective of the presence of the CFH Y402H polymorphism (p = 0.4113) and independent of the specific genotype (p = 0.9634). Conclusion In the present study exudative AMD is not associated to serum VEGF165 levels; furthermore, our data does not establish a statistical link between VEGF165 and the CFH Y402H polymorphism. PMID:21158586

  18. Phytochemical screening of the exudate of Aloe otallensis and its effect on Leishmania donovani

    Directory of Open Access Journals (Sweden)

    Zerihun Tesfaye Nigusse

    2016-06-01

    Full Text Available Objective: To evaluate the antileishmanial activity of methanolic extract of Aloe otallensis (A. otallensis on the promastigote stage of Leishmania donovani (L. donovani as compared to standard drugs and to screen its phytochemical constituents. Methods: Phytochemical screening was done by using the method mentioned by Evans and Trease on methanolic extract of the exudates of Aloe otallensis leaves. The extract was also evaluated for in vitro antileishmanial activity against L. donavani which is found from the Parasitology Unit of Black Lion Hospital. The result was compared to standard drugs of sodium stibogluconate, milfostin and paramomycin. Results: The extract has a good antileishmanial activity with an IC50 of 0.1230 μg/mL on L. donovani (AM 563. The experimental data showed that relatively it had better activity than paramomycin and milfostin but less activity than sodium stibogluconate. The data analyses were done by GraphPad Prism version 5 software after it was read by ELISA reader at the wave length of 650 nm. The phytochemical screening of the exudates of A. otallensis showed the presence of phenol, alkaloid and saponin. Conclusions: The methanol extract of the exudates of A. otallensis has a good antileishmaniasis activity and this may be attributed to phenol, alkaloid and saponin present in the plant. But it needs further analysis for the conformation of which constituent presents in high concentration to know which one has the strongest effect.

  19. Purification of exuding water in reclaimed land by combination of irradiation and biological treatment

    International Nuclear Information System (INIS)

    The dirty water exuding from garbage-filled reclaimed land contains a large quantity of organic contaminating substances. The main component of the contaminating substances is humus called humic acid and fulvic acid. It is difficult to apply biological treatment such as activated sludge process to exuding water because the biological decomposition property of the humus is generally poor. Sufficient effect cannot be expected by physicochemical process such as active carbon treatment and flocculation-precipitation treatment because the molecular weight distribution of the humus is very wide. If irradiation and biological treatment can be combined, the irradiation dose required can be largely reduced. Therefore, exuding water was sampled in Tokyo Bay No.15 reclaimed land, and Co-60 gamma ray was irradiated to see the change of its BOD. The irradiating condition in irradiation-biological treatment was clarified, and the possible method of the combined treatment was decided for trial. The peak value of BOD and the dose required to reach the peak were almost proportional to the initial concentration, and pH did not much affect the change of BOD. The low dose rate did not bring about much merit. (Kako, I.)

  20. Effect of Bark Extract and Gum Exudate of Commiphora Caudata on Aspirin Induced Ulcer in Rats

    Directory of Open Access Journals (Sweden)

    R Nanthakumar

    2009-01-01

    Full Text Available Commiphora caudata is used in Indian folk medicine as an antiulcerogenic agent. Despite of its promising use, there has been no scientific report present regarding its antiulcer activity. Therefore, this study was designed to evaluate the antiulcer activity of bark extract and gum exudate of commiphora caudata on aspirin induced ulcer in rats. Acute toxicity study was performed and 200 mg/kg was selected as an effective dose. Four groups of Albino Swiss rats were included in this study. Aspirin suspended in 0.5 % carboxymethyl cellulose (CMC was given orally to group 1 rats as a negative control group. Group 2 and group 3 animals received methanolic extract and gum exudate of commiphora caudata respectively. Sucralfate was given orally to group 4 animals as a positive control. The methanolic extract of commiphora caudata has been found to reduce total acidity as much as by sucralfate. However, it has not changed the fluid secretion. The gum preparation not only reduced the total acidity but also considerably reduce the gastric fluid secretion. In case of ulcer score sucralfate, methanolic extract and the gum have produced the low ulcer score compared to aspirin. Increased gastric mucosal protective mechanism by bark extract and gum exudate is probably due to the presence of some active principles present in the plant. However, further investigations are required to elucidate their exact mechanism of anti-ulcer activity.

  1. Phytochemical screening of the exudate of Aloe otallensis and its effect on Leishmania donovani

    Institute of Scientific and Technical Information of China (English)

    Zerihun Tesfaye Nigusse; WoldeaAbebe Wondifraw; Sefinew MigbaruAbate

    2016-01-01

    Objective: To evaluate the antileishmanial activity of methanolic extract of Aloe otallensis (A. otallensis) on the promastigote stage of Leishmania donovani (L. donovani) as compared to standard drugs and to screen its phytochemical constituents. Methods: Phytochemical screening was done by using the method mentioned by Evans and Trease on methanolic extract of the exudates of Aloe otallensis leaves. The extract was also evaluated for in vitro antileishmanial activity against L. donavani which is found from the Parasitology Unit of Black Lion Hospital. The result was compared to standard drugs of sodium stibogluconate, milfostin and paramomycin. Results: The extract has a good antileishmanial activity with an IC50 of 0.1230 μg/mL on L. donovani (AM 563). The experimental data showed that relatively it had better activity than paramomycin and milfostin but less activity than sodium stibogluconate. The data analyses were done by GraphPad Prism version 5 software after it was read by ELISA reader at the wave length of 650 nm. The phytochemical screening of the exudates of A. otallensis showed the presence of phenol, alkaloid and saponin. Conclusions: The methanol extract of the exudates of A. otallensis has a good anti-leishmaniasis activity and this may be attributed to phenol, alkaloid and saponin present in the plant. But it needs further analysis for the conformation of which constituent presents in high concentration to know which one has the strongest effect.

  2. Afrokoko Roots

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Give us a little background information about Afrokoko Roots.How long have you been performing together?It's an international Afrobeat outfit that I founded in Beijing three years ago.I founded it in order to show Chinese people that Africa is beyond what they see and hear on TV.For the purpose of cultural exchange,I hope it can help the Chinese learn about African culture,music,fashion,history and much more.Our band features two dancers,two backup singers,two percussionists,four brass players,a keyboard player,a guitar player and a drummer- and me as the lead vocal,drummer and dancer,which makes for live performances that are equally exciting sonically as they are visually.We have been traveling around,and so far,we have toured and performed in many Chinese cities such as Dalian (Liaoning Province),Hohhot (Inner Mongolia Autonomous Region) and Haikou (Hainan Province).

  3. Patterns of organic acids exuded by pioneering fungi from a glacier forefield are affected by carbohydrate sources

    International Nuclear Information System (INIS)

    Bare soils in the area of retreating glaciers are ideal environments to study the role of microorganisms in the early soil formation and in processes of mineral weathering. The aim of our study was to investigate whether the source of carbohydrate would influence the patterns of organic acids exuded by fungal species. Three pioneering fungus species, isolated from fine granitic sediments in front of the Damma glacier from the central Swiss Alps, have previously been found to have the capability to exude organic acids and dissolve granite powder. In batch experiments, various carbohydrates, including glucose, cellulose, pectin, pollen, and cell remnants of cyanobacteria, fungi, and algae, were applied as carbohydrate sources and the patterns of exuded organic acids recorded. The results showed that two fungi, the zygomycete fungus Mucor hiemalis and the ascomycete fungus Penicillium chrysogenum, released a significantly higher amount of organic acids in dependence on specific carbohydrate sources. Pollen and algae as carbohydrate sources triggered significantly the exudation of malate in M. hiemalis, and pollen and cellulose that of oxalate in P. chrysogenum. We conclude that the occurrence of complex carbohydrate sources in nutrient-deficient deglaciated soils may positively influence the exudation of organic acids of fungi. In particular, pollen and remnants of other microorganisms can trigger the exudation of organic acids of fungi in order to promote the weathering of minerals and to make nutrients available that would otherwise be trapped in that cryospheric environment. (paper)

  4. Roots at the Percolation Threshold

    Science.gov (United States)

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

    2014-12-01

    alter the soil hydraulic conductivity. Is mucilage exudation a plant mechanism to efficiently control the rhizosphere conductivity and the access to water?

  5. Intravitreal bevacizumab combined with plaque brachytherapy reduces melanoma tumor volume and enhances resolution of exudative detachment

    Directory of Open Access Journals (Sweden)

    Houston SK

    2013-01-01

    Full Text Available Samuel K Houston,1 Nisha V Shah,1 Christina Decatur,1 Marcela Lonngi,1 William Feuer,1 Arnold M Markoe,2 Timothy G Murray1–31Department of Ophthalmology, 2Department of Radiation Oncology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, 3Murray Ocular Oncology and Retina, Miami, FL, USABackground: The purpose of this study was to evaluate intravitreal bevacizumab as an adjuvant treatment to plaque brachytherapy in the treatment of choroidal melanoma.Methods: This was a retrospective, consecutive study of 124 patients treated from 2007 to 2009 for choroidal melanoma with plaque brachytherapy. Patients were treated with I-125 plaque brachytherapy with 2 mm margins and 85 Gy to the tumor apex. Consecutive patients were injected intravitreally with 2.5 mg/0.1 mL bevacizumab at a site away from the primary tumor and immediately following plaque removal. Choroidal melanomas were observed using indirect ophthalmoscopy, wide-angle photography, and ultrasound. The main outcome measures were tumor volume, resolution of exudative retinal detachment, and visual acuity.Results: One hundred and twenty-four patients met our inclusion criteria and were included in the analysis. The mean patient age was 65.7 years, and the mean apical tumor height was 4.0 ± 2.7 mm and basal diameter was 12.7 ± 3.0 mm. Mean follow-up was 24 months. Prior to treatment, 100% of tumors had exudative retinal detachment, and pretreatment visual acuity was 20/55 (median 20/40. Tumor control was 100%, metastasis was 0% at last follow-up, and 89.8% had complete resolution of exudative retinal detachment, with a mean time to resolution of 3.36 months. At one month, 43% had complete resolution of exudative retinal detachment, which increased to 73% at 4 months. Visual acuity was 20/62 (median 20/40 at 4 months, with stabilization to 20/57 (median 20/40 at 8 months, 20/56 (median 20/30 at 12 months, and 20/68 (median 20/50 at 24 months. Tumor

  6. Water percolation through the root-soil interface

    Science.gov (United States)

    Benard, Pascal; Kroener, Eva; Vontobel, Peter; Kaestner, Anders; Carminati, Andrea

    2016-04-01

    Plant roots exude a significant fraction of the carbon assimilated via photosynthesis into the soil. The mucilaginous fraction of root exudates affects the hydraulic properties of the soil near the roots, the so called rhizosphere, in a remarkable and dynamic way. After drying, mucilage becomes hydrophobic and limits the rewetting of the rhizosphere. Here, we aim to find a quantitative relation between rhizosphere rewetting, particle size, soil matric potential and mucilage concentration. We used a pore-network model in which mucilage was randomly distributed in a cubic lattice. The general idea was that the mucilage concentration per solid soil surface increases the contact angle between the liquid and solid phases consequently limiting the rewetting of pores covered with dry mucilage. We used the Young-Laplace equation to calculate the mucilage concentration at which pores are not wettable for varying particle sizes and matric potentials. Then, we simulated the percolation of water across a cubic lattice. Our simulations predicted that above a critical mucilage concentration water could not flow through the porous medium. The critical mucilage concentration decreased with increasing particle size and decreasing matric potential. The model was compared with experiments of capillary rise in soils of different particle size and mucilage concentration. The experiments confirmed the percolation behaviour of the rhizosphere rewetting. Mucilage turned hydrophobic at concentrations above 0.1 mg/cm². The critical mucilage concentration at matric potential of -2.5 hPa was ca. 1% [g/g] for fine sand and 0.1 % [g/g] for coarse sand. Our conceptual model is a first step towards a better understanding of the water dynamics in the rhizosphere during rewetting and it can be used to predict in what soil textures rhizosphere water repellency becomes a critical issue for root water uptake.

  7. Investigations into rhizosphere microflora. IV. Fungal association in different root regions of some rainy-season crops

    OpenAIRE

    V. B. Srivastava

    2015-01-01

    Non-rhizosphere, rhizosphere and rhizoplane microflora of the crown and distal regions of Echinochloa crusgalli (L.) Beauv. and Paspalum scrobiculatum L. were studied from seedling stage to the harvest. The variation in bacterial and fungal flora in relation to host species, stage of development and żonę of the rhizosphere were studied. The differences between fungal and bacterial flora are described. The relation between rhizosphere microflora and roots exudates is described.

  8. Investigations into rhizosphere microflora. IV. Fungal association in different root regions of some rainy-season crops

    Directory of Open Access Journals (Sweden)

    V. B. Srivastava

    2015-05-01

    Full Text Available Non-rhizosphere, rhizosphere and rhizoplane microflora of the crown and distal regions of Echinochloa crusgalli (L. Beauv. and Paspalum scrobiculatum L. were studied from seedling stage to the harvest. The variation in bacterial and fungal flora in relation to host species, stage of development and żonę of the rhizosphere were studied. The differences between fungal and bacterial flora are described. The relation between rhizosphere microflora and roots exudates is described.

  9. Degradation of Surfactants in Hydroponic Wheat Root Zones

    Science.gov (United States)

    Monje, Oscar; McCoy, Lashelle; Flanagan, Aisling

    Hygiene water recycling in recirculating hydroponic systems can be enhanced by plant roots by providing a substrate and root exudates for bacterial growth. However, reduced plant growth can occur during batch mode additions of high concentrations of surfactant. An analog hygiene water stream containing surfactants (Steol CS330, Mirataine CB) was added to a hydroponically-grown wheat plant root zone. The plants were grown at 700 mol mol-1 CO2, a photosynthetic photon flux of 300 mol m-2 s-1, and a planting density of 380 plants m-2. Volumetric oxygen mass transfer coefficients were determined using the fermentative/dynamic outgassing method to maintain adequate oxygen mass transfer rates in the root zone. This analysis suggested an optimal flow rate of the hydroponic solution of 5 L min-1. The hydroponic system was inoculated with biofilm from a bioreactor and rates of surfactant degradation were measured daily based on reduction in chemical oxygen demand (COD). The COD decreased from 400 to 100 mg L-1 after 2 days following batch addition of the analog hygiene water to the hydroponic system. Measurements of dissolved oxygen concentration and solution temperature suggest that the root zone was provided adequate aeration to meet both oxygen demands from plant and microbial respiration during the degradation of the surfactant. Results from this study show that hydroponic systems can be used to enhance rates of hygiene water processing.

  10. Mapping of sugar and amino acid availability in soil around roots with bacterial sensors of sucrose and tryptophan

    Science.gov (United States)

    Jaeger; Lindow; Miller; Clark; Firestone

    1999-06-01

    We developed a technique to map the availability of sugars and amino acids along live roots in an intact soil-root matrix with native microbial soil flora and fauna present. It will allow us to study interactions between root exudates and soil microorganisms at the fine spatial scale necessary to evaluate mechanisms of nitrogen cycling in the rhizosphere. Erwinia herbicola 299R harboring a promoterless ice nucleation reporter gene, driven by either of two nutrient-responsive promoters, was used as a biosensor. Strain 299RTice exhibits tryptophan-dependent ice nucleation activity, while strain 299R(p61RYice) expresses ice nucleation activity proportional to sucrose concentration in its environment. Both biosensors exhibited up to 100-fold differences in ice nucleation activity in response to varying substrate abundance in culture. The biosensors were introduced into the rhizosphere of the annual grass Avena barbata and, as a control, into bulk soil. Neither strain exhibited significant ice nucleation activity in the bulk soil. Both tryptophan and sucrose were detected in the rhizosphere, but they showed different spatial patterns. Tryptophan was apparently most abundant in soil around roots 12 to 16 cm from the tip, while sucrose was most abundant in soil near the root tip. The largest numbers of bacteria (determined by acridine orange staining and direct microscopy) occurred near root sections with the highest apparent sucrose or tryptophan exudation. High sucrose availability at the root tip is consistent with leakage of photosynthate from immature, rapidly growing root tissues, while tryptophan loss from older root sections may result from lateral root perforation of the root epidermis. PMID:10347061

  11. Determination of proline concentration, an abiotic stress marker, in root exudates of excised root cultures of fruit tree rootstocks under salt stress

    OpenAIRE

    Marín Velázquez, Juan Antonio; Andreu Puyal, Pilar; A. Carrasco; Arbeloa Matute, Arancha

    2010-01-01

    6 páginas, 4 figuras.-- Trabajo presentado Actes du 3º Meeting International "Aridoculture et Cultures Oasisennes: Gestion et Valorisation des Ressources et Applications Biotechnologiques dans les Agrosystèmes Arides et Sahariens" celebrado en Jerba (Túnez) del 15 al 17 de Diciembre de 2009. 15-16-17/12/2009

  12. Root phenology in a changing climate.

    Science.gov (United States)

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

    2016-06-01

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

  13. Adjustment of Forest Ecosystem Root Respiration as Temperature Warms

    Institute of Scientific and Technical Information of China (English)

    Andrew J. Burton; Jerry M. Melillo; Serita D. Frey

    2008-01-01

    Adjustment of ecosystem root respiration to warmer climatic conditions can alter the autotrophic portion of soil respiration and influence the amount of carbon available for biomass production. We examined 44 published values of annual forest root respiration and found an increase in ecosystem root respiration with increasing mean annual temperature (MAT),but the rate of this cross-ecosystem increase (Q10 = 1.6) is less than published values for short-term responses of root respiration to temperature within ecosystems (Q10 = 2-3). When specific root respiration rates and root biomass values were examined, there was a clear trend for decreasing root metabolic capacity (respiration rate at a standard temperature) with increasing MAT. There also were tradeoffs between root metabolic capacity and root system biomass, such that there were no instances of high growing season respiration rates and high root biomass occurring together. We also examined specific root respiration rates at three soil warming experiments at Harvard Forest, USA, and found decreases in metabolic capacity for roots from the heated plots. This decline could be due to either physiological acclimation or to the effects of co-occurring drier soils on the measurement date. Regardless of the cause, these findings clearly suggest that modeling efforts that allow root respiration to increase exponentially with temperature, with Qt0 values of 2 or more, may over-predict root contributions to ecosystem CO2 efflux for future climates and underestimate the amount of C available for other uses,including net primary productivity.

  14. Root canal irrigants

    OpenAIRE

    Kandaswamy Deivanayagam; Venkateshbabu Nagendrababu

    2010-01-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are...

  15. Gelation of Soy Milk with Hagfish Exudate Creates a Flocculated and Fibrous Emulsion- and Particle Gel.

    Directory of Open Access Journals (Sweden)

    Lukas Böni

    Full Text Available Hagfish slime is an ultra dilute, elastic and cohesive hydrogel that deploys within milliseconds in cold seawater from a glandularly secreted exudate. The slime is made of long keratin-like fibers and mucin-like glycoproteins that span a network which entraps water and acts as a defense mechanism against predators. Unlike other hydrogels, the slime only confines water physically and is very susceptible to mechanical stress, which makes it unsuitable for many processing operations and potential applications. Despite its huge potential, little work has been done to improve and functionalize the properties of this hydrogel. To address this shortcoming, hagfish exudate was mixed with a soy protein isolate suspension (4% w/v and with a soy emulsion (commercial soy milk to form a more stable structure and combine the functionalities of a suspension and emulsion with those of the hydrogel. Hagfish exudate interacted strongly with the soy systems, showing a markedly increased viscoelasticity and water retention. Hagfish mucin was found to induce a depletion and bridging mechanism, which caused the emulsion and suspension to flocculate, making "soy slime", a cohesive and cold-set emulsion- and particle gel. The flocculation network increases viscoelasticity and substantially contributes to liquid retention by entrapping liquid in the additional confinements between aggregated particles and protein fibers. Because the mucin-induced flocculation resembles the salt- or acid-induced flocculation in tofu curd production, the soy slime was cooked for comparison. The cooked soy slime was similar to conventional cooked tofu, but possessed a long-range cohesiveness from the fibers. The fibrous, cold-set, and curd-like structure of the soy slime represents a novel way for a cold coagulation and fiber incorporation into a suspension or emulsion. This mechanism could be used to efficiently gel functionalized emulsions or produce novel tofu-like structured food

  16. Gelation of Soy Milk with Hagfish Exudate Creates a Flocculated and Fibrous Emulsion- and Particle Gel.

    Science.gov (United States)

    Böni, Lukas; Rühs, Patrick A; Windhab, Erich J; Fischer, Peter; Kuster, Simon

    2016-01-01

    Hagfish slime is an ultra dilute, elastic and cohesive hydrogel that deploys within milliseconds in cold seawater from a glandularly secreted exudate. The slime is made of long keratin-like fibers and mucin-like glycoproteins that span a network which entraps water and acts as a defense mechanism against predators. Unlike other hydrogels, the slime only confines water physically and is very susceptible to mechanical stress, which makes it unsuitable for many processing operations and potential applications. Despite its huge potential, little work has been done to improve and functionalize the properties of this hydrogel. To address this shortcoming, hagfish exudate was mixed with a soy protein isolate suspension (4% w/v) and with a soy emulsion (commercial soy milk) to form a more stable structure and combine the functionalities of a suspension and emulsion with those of the hydrogel. Hagfish exudate interacted strongly with the soy systems, showing a markedly increased viscoelasticity and water retention. Hagfish mucin was found to induce a depletion and bridging mechanism, which caused the emulsion and suspension to flocculate, making "soy slime", a cohesive and cold-set emulsion- and particle gel. The flocculation network increases viscoelasticity and substantially contributes to liquid retention by entrapping liquid in the additional confinements between aggregated particles and protein fibers. Because the mucin-induced flocculation resembles the salt- or acid-induced flocculation in tofu curd production, the soy slime was cooked for comparison. The cooked soy slime was similar to conventional cooked tofu, but possessed a long-range cohesiveness from the fibers. The fibrous, cold-set, and curd-like structure of the soy slime represents a novel way for a cold coagulation and fiber incorporation into a suspension or emulsion. This mechanism could be used to efficiently gel functionalized emulsions or produce novel tofu-like structured food products. PMID:26808048

  17. Hyperbaric oxygen increases plasma exudation in rat trachea: involvement of nitric oxide

    Science.gov (United States)

    Bernareggi, M; Radice, S; Rossoni, G; Oriani, G; Chiesara, E; Berti, F

    1999-01-01

    This study investigates the microvascular permeability changes in tracheal tissue of rats exposed to hyperbaric oxygen (HBO). Rats, following exposure to HBO or ambient air (control animals) for 1.5, 3 and 6 h, were prepared for recording of nitric oxide exhaled (FENO) in air using a chemiluminescence analyser. The level of FENO was not statistically different in the two groups. Plasma exudation, evaluated by measuring the leakage of Evans blue (EB) dye into the tracheal tissue, was significantly elevated (48, 86 and 105% at 1.5, 3 and 6 h, respectively) in HBO-treated rats. Plasma exudation in the trachea of control rats was significantly increased (42%, P<0.05) by NG-nitro-L-arginine methyl ester (L-NAME), whereas it was significantly reduced (31%, P<0.05) in rats exposed to HBO for 3 h. N-acetylcysteine (NAC) and flunisolide significantly prevented the increase in plasma leakage in HBO-treated rats. In contrast, indomethacin was devoid of anti-exudative activity in these experiments. Western immunoblot showed a significant increase in the level of inducible nitric oxide synthase (iNOS) protein in the tracheal homogenates of HBO-treated rats, as compared to basal levels. These results indicate that nitric oxide (NO) is involved in the maintenance of microvascular permeability in tracheal tissue of rats. The protective effect observed with the steroid seems to support this hypothesis. Furthermore, the beneficial action of NAC underlines that reactive oxygen species participate in the microvascular permeability changes observed in tracheal tissue of rats exposed to HBO. PMID:10188993

  18. The Root Cap Determines Ethylene-Dependent Growth and Development in Maize Roots

    Institute of Scientific and Technical Information of China (English)

    Achim Hahn; Roman Zimmermann; Dierk Wanke; Klaus Harter; Hans G.Edelmann

    2008-01-01

    Besides providing protection against mechanical damage to the root tip,the root cap is involved in the perception and processing of diverse external and internal stimuli resulting in altered growth and development.The transduction of these stimuli includes hormonal signaling pathways such as those of auxin,ethylene and cytokinin.Here,we show that the root cap is essential for the ethylene-induced regulation of elongation growth and root hair formation in maize.Exogenously applied ethylene is no longer able to inhibit elongation growth when the root cap has been surgically removed prior to hormone treatment.Reconstitution of the cap positively correlates with the developing capacity of the roots to respond to ethylene again.In contrast,the removal of the root cap does not per se affect growth inhibition controlled by auxin and cytokinin.Furthermore,our semi-quantitative RT-PCR results support earlier findings that the maize root cap is a site of high gene expression activity with respect to sensing and responding to hormones such as ethylene.From these data,we propose a novel function of the root cap which is the establishment of competence to respond to ethylene in the distal zones of the root.

  19. Status of Exudative Pleural Effusion in Adults of South Khorasan Province, Northeast Iran: Pleural Tuberculosis Tending toward Elderly

    Science.gov (United States)

    Mortazavi-Moghaddam, Sayyed Gholam Reza; Sharifzadeh, Gholam Reza; Rezvani, Mohammad Reza

    2016-01-01

    The causes and situation of exudative pleural effusion vary from one area to another. A cross-sectional study was conducted on 327 patients with exudative pleural effusion in South Khorasan province (Iran). The patients were older than 12 years and comprised 172 (52.6%) males and 155 (47.4%) females. The study commenced in 2007 with seven years duration. The Light’s criteria were used to define exudative effusion. Procedures including pleural fluid analysis, microbiological study, pleural biopsy, and systemic investigations were conducted to determine the special cause of pleural effusion. The mean age of the patients was 63.4±18.4 years. Malignancies, tuberculosis, and parapneumonia pleural exudation were diagnosed in 125 (38.2%), 48 (14.7%), and 45 (13.8%) cases, respectively. Among malignant effusions, metastasis from lung cancer made 48 (38.4%) of the cases. The origin of metastasis was not determined in 44 (35.2%) patients. The mean age of patients was not significantly different between malignant (66.9±14.3 years) and tuberculosis (63.9±19.7 years) cases (P=0.16). The older age of tuberculosis patients could be a new discussion point on the overall impression created on the subject of tuberculosis pleural exudation (TB-PLE) occurring in young people. PMID:27365554

  20. Vitrectomy for circumscribed choroidal hemangioma with exudative retinal detachment refractory to transpupillary thermotherapy

    Directory of Open Access Journals (Sweden)

    Shukla Dhananjay

    2007-01-01

    Full Text Available We report successful surgical management of a circumscribed choroidal hemangioma with exudative retinal detachment refractory to transpupillary thermotherapy (TTT. A 33-year-old man with symptomatic serous macular detachment in the left eye (Snellen acuity: 20/200 secondary to a paramacular choroidal hemangioma was treated with TTT. The nonresponsive detachment was subsequently managed by vitrectomy, endophotocoagulation and silicon-oil tamponade. It resulted in complete resolution of the tumor and the detachment. Silicon oil was removed at four months. Visual acuity improved to 20/80 by the last follow-up visit at 10 months without any recurrence.

  1. Microbial impacts on the migration of actinides. Effects of exudates on adsorption

    International Nuclear Information System (INIS)

    The interaction of actinides with microorganisms has been extensively studied to elucidate migration behavior of actinides in the environments. However, the mechanisms of interaction of microorganisms and actinides are poorly understood. We have been conducting basic science on microbial accumulation of actinides in order to elucidate the environmental behavior of actinides under relevant conditions. The effect of exudates from bacteria cells on the sorption of Eu(III) and Cm(III) by Chlorella vulgaris was studied by a batch method. The pH dependence of log Kd of Eu(III) and Cm(III) for cellulose, major component of C. vulgaris cell, differed from that for C. vulgaris. On the contrary, log Kd of Eu(III) and Cm(III) for cellulose in the solution containing exudates from C. vulgaris cells in a 0.5% NaCl solution showed a similar pH dependence to that by C. vulgaris. These results strongly suggested that exudates affect on the sorption of Eu(III) and Cm(III) on C. vulgaris. Effect of desferrioxamine B (DFO), one of exudates to chelate with insoluble Fe(III), on the sorption of Pu(IV), Th(IV) and Eu(III) by Pseudomonas fluorescens was studied. In the presence of DFO the sorption of Pu(IV), Th(IV) and Eu(III) on the cells increased with a decrease in pH from 7 to 4. In contrast, without DFO most of Pu(IV), Th(IV) and Eu(III) were precipitated from solution. Adsorption of DFO on the cells was negligible in the solution with and without metals. Adsorption of Pu(IV), Th(IV) and Eu(III) on P. fluorescens cells decreased in the order Eu(III) > Th(IV) > Pu(IV), which corresponds to increasing stability constant of the DFO complexes. These results indicate that Th(IV), Pu(IV) and Eu(III) dissociate when in contact with cells, after which the metals are adsorbed. (author)

  2. MICROBIAL IMPACTS ON THE MIGRATION OF ACTINIDES -EFFECTS OF EXUDATES ON ADSORPTION-

    International Nuclear Information System (INIS)

    The interaction of actinides with microorganisms has been extensively studied to elucidate migration behavior of actinides in the environments. However, the mechanisms of interaction of microorganisms and actinides are poorly understood. They have been conducting basic science on microbial accumulation of actinides in order to elucidate the environmental behavior of actinides under relevant conditions. The effect of exudates from bacteria cells on the sorption of Eu(III) and Cm(III) by Chlorella vulgaris was studied by a batch method. The pH dependence of log Kd of Eu(III) and Cm(III) for cellulose, major component of C. vulgaris cell, differed from that for C. vulgaris. On the contrary, log Kd of Eu(III) and Cm(III) for cellulose in the solution containing exudates from C. vulgaris cells in a 0.5% NaCl solution showed a similar pH dependence to that by C. vulgaris. These results strongly suggested that exudates affect on the sorption of Eu(III) and Cm(III) on C. vulgaris. Effect of desferrioxamine B (DFO), one of exudates to chelate the insoluble Fe(III), on the sorption of Pu(IV), Th(IV) and Eu(III) by Pseudomonas fluorescens was studied. In the presence of DFO the sorption of Pu(IV), Th(IV) and Eu(III) on the cells increased with a decrease in pH from 7 to 4. In contrast, without DFO most of Pu(IV), Th(IV) and Eu(III) were precipitated from solution. Adsorption of DFO on the cells was negligible in the solution with and without metals. Adsorption of Pu(IV), Th(IV) and Eu(III) on P. fluorescens cells decreased in the order Eu(III) > Th(IV) > Pu(IV), which corresponds to increasing stability constant of the DFO complexes. These results indicate that Th(IV), Pu(IV) and Eu(III) dissociate when in contact with cells, after which the metals are adsorbed

  3. pH of exudate test in the physiological quality of crambe seeds

    OpenAIRE

    Charline Zaratin Alves; Lennis Afraire Rodrigues; Carlos Henrique Queiroz Rego; Josué Bispo da Silva

    2016-01-01

    ABSTRACT: Crambe is a rapeseed with high oil content and can be used as a winter cover or as a source of raw material for the production of biodiesel, however espite the growing interest in the culture, research on the subject is still incipient, especially concerning the seed production and analysis technology. The purpose of this study is to evaluate the physiological quality of crambe seeds, 'FMS Brilhante' cultivar, by testing the pH of exudate. Five seed lots were submitted to the determ...

  4. A case of von Hippel-Lindau disease with exudative maculopathy

    Directory of Open Access Journals (Sweden)

    Ba′arah Basel

    2009-01-01

    Full Text Available Von Hippel-Lindau (VHL disease is a rare multisystem familial tumor syndrome of autosomal dominant inheritance. Hallmark lesions include retinal, cerebellum and spinal cord hemangioblastomas, renal cell carcinomas, adrenal pheochromocytomas, angiomatous or cystic lesions of the kidneys, pancreas, and epididymis. We report a case of VHL disease in a 26-year-old patient who presented with exudative macular edema. Ocular and systemic studies revealed the presence of retinal and central nervous system hemangioblastomas, adrenal pheochromocytoma, multiple pancreatic, and kidney cysts. The retinal angiomas were successfully treated with argon laser photocoagulation and cryotherapy.

  5. Prophylactic laser treatment in early age related maculopathy reduced the incidence of exudative complications

    OpenAIRE

    Frennesson, C; Nilsson, S.

    1998-01-01

    AIM—To investigate the effect of prophylactic laser treatment on drusen area and incidence of exudative lesions in patients with soft drusen maculopathy.
METHODS—In a prospective study, patients with early age related maculopathy (ARM) and good visual acuity were randomised to laser treatment or to a control group. Each group consisted of two subgroups: a fellow eye group and a bilateral drusen group. At 3 years, 36 of 38 enrolled patients remained in the study. Photocoagulation was performed...

  6. A case of von Hippel-Lindau disease with exudative maculopathy.

    Science.gov (United States)

    Ba Arah, Basel T

    2009-05-01

    Von Hippel-Lindau (VHL) disease is a rare multisystem familial tumor syndrome of autosomal dominant inheritance. Hallmark lesions include retinal, cerebellum and spinal cord hemangioblastomas, renal cell carcinomas, adrenal pheochromocytomas, angiomatous or cystic lesions of the kidneys, pancreas, and epididymis. We report a case of VHL disease in a 26-year-old patient who presented with exudative macular edema. Ocular and systemic studies revealed the presence of retinal and central nervous system hemangioblastomas, adrenal pheochromocytoma, multiple pancreatic, and kidney cysts. The retinal angiomas were successfully treated with argon laser photocoagulation and cryotherapy. PMID:20671835

  7. The importance of serum lipids in exudative diabetic macular edema in type 2 diabetic patients.

    Science.gov (United States)

    Uçgun, Nil Irem; Yildirim, Zuhal; Kiliç, Nedret; Gürsel, Emin

    2007-04-01

    To evaluate the relationship between serum lipid levels and exudative diabetic maculopathy in patients with nonproliferative diabetic retinopathy, 27 patients with exudative diabetic macular edema were included in group A and 27 patients without exudative diabetic macular edema were included in group B. All 54 patients have nonproliferative diabetic retinopathy. Blood cholesterol, triglyceride, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL) cholesterol, hemoglobin A1c (HbA1c), and hemoglobin levels were measured in patients in group A and group B. The mean concentration of cholesterol in group A (224.30 +/- 49.49 mg/dL), in group B (197.78 +/- 41.49 mg/dL); triglyceride in group A (199.11 +/- 90.51 mg/dL), in group B (160.78 +/- 65.30 mg/dL); HDL in group A (43.48 +/- 10.62 mmol/L), in group B (42.37 +/- 10.92 mmol/L); LDL in group A (150.59 +/- 43.96 mg/dL), in group B (124.37 +/- 40.28 mg/dL); VLDL in group A (40.52 +/- 16.54 mg/dL), in group B (37.89 +/- 23.70 mg/dL); HbA1c in group A (9.62 +/- 2.50), in group B (7.36 +/- 1.62 g/dL); and hemoglobin in group A (13.46 +/- 1.6 g/dL), in group B (13.90 +/- 1.77 g/dL). Serum cholesterol (P = 0.38), LDL (P = 0.026), and HbA1c (P = 0.000) levels were different between the two groups. Triglyceride, HDL, VLDL, and hemoglobin levels were not different between the two groups. We must consider regulation of high blood sugar and elevated total serum cholesterol or LDL levels in patients with macular edema and high hard exudates. PMID:17460181

  8. Acute exudative polymorphous vitelliform maculopathy in a patient with Lyme disease.

    Science.gov (United States)

    Singh, Ravi S J; Tran, Lac H; Kim, Judy E

    2013-01-01

    Acute exudative polymorphous vitelli-form maculopathy (AEPVM) is a rare condition of unclear etiology that has been seen in association with respiratory and viral infections. It has also been reported as a paraneoplastic phenomenon in older individuals. The authors report the first case of AEPVM associated with Lyme disease with over 3.5 years of follow-up. Multimodality serial imaging suggested the lesions began as multiple serous detachments followed by accumulation of photoreceptor outer segments in the subretinal space that gradually resolved over time and gave rise to the characteristic fundus findings at various stages. PMID:24044715

  9. Organic matter exudation by Emiliania huxleyi under simulated future ocean conditions

    Directory of Open Access Journals (Sweden)

    A. Engel

    2012-01-01

    Full Text Available Emiliania huxleyi (strain B 92/11 was exposed to different growth, CO2 and temperature conditions in phosphorous controlled chemostats, to investigate effects on organic carbon exudation, and partitioning between the pools of particulate organic carbon (POC and dissolved organic carbon (DOC. 14C incubation measurements for primary production (PP and for extracellular release (ER were performed. Chemical analysis included amount and composition of high molecular weight dissolved combined carbohydrates (>1 kDa, HMW-dCCHO, particulate combined carbohydrates (pCCHO and the carbon content of transparent exopolymer particles (TEP-C. Applied CO2 and temperature conditions were 300, 550 and 900 μatm pCO2 at 14 °C, and additionally 900 μatm pCO2 at 18 °C simulating a greenhouse ocean scenario. A reduction in growth rate from μ =0.3 d−1 to μ =0.1 d−1 induced the most profound effect on the performance of E. huxleyi, relative to the effect of elevated CO2 and temperature. At μ =0.3 d−1, PP was significantly higher at elevated CO2 and temperature. DO14C production correlated to PO14C production in all cultures, resulting in similar percentages of extracellular release (DO14C/PP × 100; PER of averaged 3.74 ± 0.94%. At μ =0.1 d−1, PO14C decreased significantly, while exudation of DO14C increased, thus leading to a stronger partitioning from the particulate to the dissolved pool. Maximum PER of 16.3 ± 2.3% were observed at μ =0.1 d−1 at greenhouse conditions. Concentrations of HMW-dCCHO and pCCHO were generally higher at μ =0.1 d−1 compared to μ =0.3 d−1. At μ =0.3 d−1, pCCHO concentration increased significantly along with elevated CO2 and temperature. Despite of high PER, the percentage of HMW-dCCHO was smallest at greenhouse conditions. However, highest TEP-formation was observed under greenhouse conditions, together with a pronounced increase in pCCHO concentration, suggesting a stronger partitioning of PP from DOC to POC

  10. Plant-Microbe Communication Enhances Auxin Biosynthesis by a Root-Associated Bacterium, Bacillus amyloliquefaciens SQR9.

    Science.gov (United States)

    Liu, Yunpeng; Chen, Lin; Zhang, Nan; Li, Zunfeng; Zhang, Guishan; Xu, Yu; Shen, Qirong; Zhang, Ruifu

    2016-04-01

    Mechanisms by which beneficial rhizobacteria promote plant growth include tryptophan-dependent indole-3-acetic acid (IAA) synthesis. The abundance of tryptophan in the rhizosphere, however, may influence the level of benefit provided by IAA-producing rhizobacteria. This study examined the cucumber-Bacillus amyloliquefaciens SQR9 system and found that SQR9, a bacterium previously shown to enhance the growth of cucumber, increased root secretion of tryptophan by three- to fourfold. Using a split-root system, SQR9 colonization of roots in one chamber not only increased tryptophan secretion from the noninoculated roots but also increased the expression of the cucumber tryptophan transport gene but not the anthranilate synthesis gene in those roots. The increased tryptophan in isolated rhizosphere exudates was sufficient to support increased IAA production by SQR9. Moreover, SQR9 colonization of roots in one chamber in the split-root system resulted in sufficient tryptophan production by the other roots to upregulate SQR9 IAA biosynthesis genes, including a 27-fold increase in the indole-3-acetonitrilase gene yhcX during subsequent colonization of those roots. Deletion of yhcX eliminated SQR9-mediated increases in root surface area, likely by reducing IAA-stimulated lateral root growth. This study demonstrates a chemical dialogue between B. amyloliquefaciens and cucumber in which this communication contributes to bacteria-mediated plant-growth enhancement. PMID:26808445

  11. Sympathectomy attenuates excitability of dorsal root ganglion neurons and pain behaviour in a lumbar radiculopathy model

    OpenAIRE

    Iwase, T; Takebayashi, T; Tanimoto, K; Terashima, Y.; Miyakawa, T.; Kobayashi, T.; Tohse, N.; Yamashita, T

    2012-01-01

    Objectives In order to elucidate the influence of sympathetic nerves on lumbar radiculopathy, we investigated whether sympathectomy attenuated pain behaviour and altered the electrical properties of the dorsal root ganglion (DRG) neurons in a rat model of lumbar root constriction. Methods Sprague-Dawley rats were divided into three experimental groups. In the root constriction group, the left L5 spinal nerve root was ligated proximal to the DRG as a lumbar radiculopathy model. In the root con...

  12. Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress.

    Science.gov (United States)

    Pandey, Renu; Zinta, Gaurav; AbdElgawad, Hamada; Ahmad, Altaf; Jain, Vanita; Janssens, Ivan A

    2015-01-01

    Atmospheric [CO2] has increased substantially in recent decades and will continue to do so, whereas the availability of phosphorus (P) is limited and unlikely to increase in the future. P is a non-renewable resource, and it is essential to every form of life. P is a key plant nutrient controlling the responsiveness of photosynthesis to [CO2]. Increases in [CO2] typically results in increased biomass through stimulation of net photosynthesis, and hence enhance the demand for P uptake. However, most soils contain low concentrations of available P. Therefore, low P is one of the major growth-limiting factors for plants in many agricultural and natural ecosystems. The adaptive responses of plants to [CO2] and P availability encompass alterations at morphological, physiological, biochemical and molecular levels. In general low P reduces growth, whereas high [CO2] enhances it particularly in C3 plants. Photosynthetic capacity is often enhanced under high [CO2] with sufficient P supply through modulation of enzyme activities involved in carbon fixation such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). However, high [CO2] with low P availability results in enhanced dry matter partitioning towards roots. Alterations in below-ground processes including root morphology, exudation and mycorrhizal association are influenced by [CO2] and P availability. Under high P availability, elevated [CO2] improves the uptake of P from soil. In contrast, under low P availability, high [CO2] mainly improves the efficiency with which plants produce biomass per unit P. At molecular level, the spatio-temporal regulation of genes involved in plant adaptation to low P and high [CO2] has been studied individually in various plant species. Genome-wide expression profiling of high [CO2] grown plants revealed hormonal regulation of biomass accumulation through complex transcriptional networks. Similarly, differential transcriptional regulatory networks are involved in P

  13. Use of a new silver barrier dressing, ALLEVYN Ag in exuding chronic wounds.

    LENUS (Irish Health Repository)

    Kotz, Paula

    2009-06-01

    Recognising and managing wounds at risk of infection is vital in wound management. ALLEVYN Ag dressings have been designed to manage exudate in chronic wounds that are at risk of infection; are displaying signs of local infection; or where a suspected increase in bacterial colonisation is delaying healing. They combine an absorbent silver sulfadiazine containing hydrocellular foam layer, with a perforated wound contact layer and highly breathable top film. The results presented are from a multi-centre clinical evaluation of 126 patients conducted to assess the performance of ALLEVYN Ag (Adhesive, Non Adhesive and Sacrum dressings) in a range of indications. Clinicians rated the dressings as acceptable for use in various wound types in 88% of patients. The majority of clinical signs of infection reduced between the initial and the final assessment. The condition of wound tissue and surrounding skin was observed to improve, and there was significant evidence of a reduction in the level of exudate from initial to final assessment (p < 0.001). Clinicians rated ALLEVYN Ag as satisfying or exceeding expectations in over 90% of patients. The evaluation showed the dressings to offer real benefits to patients and clinicians across multiple indications when used in conjunction with local protocols.

  14. Inf luence of Spirulina platensis exudates on the endocrine and nervous systems of a mammalian model

    Institute of Scientific and Technical Information of China (English)

    Samah; Mamdouh; Mohamed; Fathy; Ashraf; Mohamed; Mohamed; Essa

    2015-01-01

    Objective: To investigate the ef ect of intra-peritoneal injection of purii ed exudates of axenic Spirulina platensis on the mammalian endocrine and nervous systems. Methods: The intra-peritoneal injection of the cyanobacterial exudates in mice was applied. Sex hormonal levels of testosterone and progesterone were measured using radioimmunoassay while the follicular stimulating hormone and luteinizing hormone were evaluated by direct chemiluminescence. In addition, superoxide dismutase, catalase and glutathione peroxidase were monitored in the hippocampus region using spectrophotometric method. The levels of the hippocampal monoamines, dopamine, noradrenaline and serotonin were analyzed by high performance liquid chromatography while the acetyl choline neurotransmitter was measured by colorimetric method using choline/acetylcholine assay kit. Results: A sharp disruption in the sex hormones levels of testosterone, progesterone, follicular stimulating hormone and luteinizing hormone was demonstrated in the serum of the treated mice. At the same time, a signii cant reduction in the endogenous antioxidant defense enzymes, superoxide dismutase, catalase and glutathione peroxidase was observed in the hippocampus region of the injected mice. Moreover, levels of dopamine, noradrenaline, serotonin and acetyl choline neurotransmitter in the same region were signii cantly af ected as a result of the treatment with Spirulina i ltrate. The gas chromatography-mass spectrometer and liquid chromatography mass spectrometry/mass spectrometry analysis showed the presence of some sterol-like compounds in the cyanobacterial i ltrate. Conclusions: This study demonstrated the capability of Spirulina to release detrimental bioactive metabolites into their surrounding that can disrupt the mammalian endocrine and nervous systems.

  15. Recent advances in Rosaceae gum exudates: From synthesis to food and non-food applications.

    Science.gov (United States)

    Bouaziz, Fatma; Koubaa, Mohamed; Ellouz Ghorbel, Raoudha; Ellouz Chaabouni, Semia

    2016-05-01

    In recent years, great interest has been devoted to the development of new applications for natural gums. These molecules were used for a variety of purposes since they are chemically inert, non-toxic, less expensive, biodegradable and widely available. They represent one of the most abundant raw materials used not only in commercial food products, but also in cosmetic and pharmaceutical products. Plant gums take their advantages compared to other gums (e.g., from animal and microbial sources) mainly because of their acceptance by consumers. Despite of the well description given in literature for the features of plant gum exudates, there is a lack distinguishing the different families that are producing gums, and their potential applications. Among these gums, the ones produced by Rosaceae family (e.g., almond, apricot, cherry, peach, and plum plants) have been taking special attention. Thus, the aim of this review is to report the recent advances in Rosaceae gum exudates. An emphasis is given for the formation mechanisms of these gums, their chemical composition, functional properties and structures, beneficial properties, as well as their food/non-food applications. PMID:26836615

  16. Linkage and candidate gene analysis of X-linked familial exudative vitreoretinopathy

    Energy Technology Data Exchange (ETDEWEB)

    Shastry, B.S.; Hartzer, M.K. [Oakland Univ., Rochester, MI (United States); Hejtmancik, J.F. [National Eye Institute, Bethesda, MD (United States)] [and others

    1995-05-20

    Familial exudative vitreoretinopathy (FEVR) is a hereditary eye disorder characterized by avascularity of the peripheral retina, retinal exudates, tractional detachment, and retinal folds. The disorder is most commonly transmitted as an autosomal dominant trait, but X-linked transmission also occurs. To initiate the process of identifying the gene responsible for the X-linked disorder, linkage analysis has been performed with three previously unreported three- or four-generation families. Two-point analysis showed linkage to MAOA (Z{sub max} = 2.1, {theta}{sub max} = 0) and DXS228 (Z{sub max} = 0.5, {theta}{sub max} = 0.11), and this was further confirmed by multipoint analysis with these same markers (Z{sub max} = 2.81 at MAOA), which both lie near the gene causing Norrie disease. Molecular genetic analysis further reveals a missense mutation (R121W) in the third exon of the Norrie`s disease gene that perfectly cosegregates with the disease through three generations in one family. This mutation was not detected in the unaffected family members and six normal unrelated controls, suggesting that it is likely to be the pathogenic mutation. Additionally, a polymorphic missense mutation (H127R) was detected in a severely affected patient. 21 refs., 3 figs., 1 tab.

  17. Characteristics of Indocyanine Green Angiography in Exudative Age—related Macular Degeneration

    Institute of Scientific and Technical Information of China (English)

    WuDZ; WenF

    1999-01-01

    Objective:To observe the characteristics of indocyanine green angiography(ICGA)in exudative age-related macular degeneration(AMD).Methods:Thirty-one cases(39 eyes)were diagnosed as exudative AMD by ocular examination,fundus color photography,fundus fluorescein angiography(FFA)and ICGA.Their ages ranged from 50 to 82 years and visual acuities from FC/30cm to 0.7.We analyzed and compared the characteristics of ICGA and FFA in these patients.Results:of 26 eyes with ccult choroidal neovascularization (CNV)by FFA,15(57.7%)had classic CNV by ICGA.Of 4 eyes with serous retinal pigment epithelial detachment(PED)without CNV by FFA,1 had serous PED with classic CNV by ICGA.The hyperfluorescence of the scar staining was detecfed by ICGA.Conclusion:ICGA adds clinically useful information and is an important adjunct in the evaluation,classification,and laser treatment of patients with occult CNV in AMD.

  18. Dipeptidyl peptidase-IV (DPP-IV inhibitory activity of parotid exudate of Bufo melanostictus

    Directory of Open Access Journals (Sweden)

    Allenki Venkatesham

    2009-01-01

    Full Text Available Type 2 diabetes arises as a result of β-cell failure combined with concomitant insulin resistance. Glucagon-like peptide-1 is a gastrointestinal hormone that is released postprandially from the L cells of the gut and exerts a glucose- dependent and direct insulinotropic effect on the pancreatic β cell. Which activate adenylate cyclase and enhances insulin secretion. GLP-1 is rapidly degraded by DPP-IV to GLP-1(9-37 amide following release from gut L cells. GLP-1 directly enhances glucose-dependent insulin secretion via an increase in β-cell cAMP. Dipeptidyl peptidase IV (DPP-IV is a plasma membrane glycoprotein ectopeptidase. In mammals, DPP-IV was widely expressed on the surface of endothelial and epithelial cells and highest levels in humans have been reported to occur in the intestine, bone marrow and kidney. Inhibiting DPP-IV reduces its rapid degradation of GLP-1, increasing circulating levels of the active hormone in vivo and prolonging its beneficial effects. The IC 50 value of parotid exudate was found to be 9.4 μg/ml. The maximum % inhibition (61.8 was showed at a concentration of 12μg/ml. Parotid exudate through inhibition of DPP-IV, improves glucose tolerance and enhances insulin secretion. DPP-IV inhibitors are a novel class of oral hypoglycemic agents with a potential to improve pancreatic beta cell function and the clinical course of type 2 diabetes.

  19. Argentinean propolis from Zuccagnia punctata Cav. (Caesalpinieae) exudates: phytochemical characterization and antifungal activity.

    Science.gov (United States)

    Agüero, María Belén; Gonzalez, Mariela; Lima, Beatriz; Svetaz, Laura; Sánchez, Marianela; Zacchino, Susana; Feresin, Gabriela Egly; Schmeda-Hirschmann, Guillermo; Palermo, Jorge; Wunderlin, Daniel; Tapia, Alejandro

    2010-01-13

    This paper reports the in vitro antifungal activity of propolis extracts from the province of Tucuman (Argentina) as well as the identification of their main antifungal compounds and botanical origin. The antifungal activity was determined by the microdilution technique, using reference microorganisms and clinical isolates. All dermatophytes and yeasts tested were strongly inhibited by different propolis extracts (MICs between 16 and 125 microg mL(-1)). The most susceptible species were Microsporum gypseum, Trichophyton mentagrophytes, and Trichophyton rubrum. The main bioactive compounds were 2',4'-dihydroxy-3'-methoxychalcone 2 and 2',4'-dihydroxychalcone 3. Both displayed strong activity against clinical isolates of T. rubrum and T. mentagrophytes (MICs and MFCs between 1.9 and 2.9 microg mL(-1)). Additionally, galangin 5, pinocembrin 6, and 7-hydroxy-8-methoxyflavanone 9 were isolated from propolis samples and Zuccagnia punctata exudates, showing moderate antifungal activity. This is the first study matching the chemical profile of Z. punctata Cav. exudates with their corresponding propolis, giving strong evidence on the botanical origin of the studied propolis. PMID:19916546

  20. Exudate-based diabetic macular edema detection in fundus images using publicly available datasets

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Garg, Seema [University of North Carolina; Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy. In a large scale screening environment DME can be assessed by detecting exudates (a type of bright lesions) in fundus images. In this work, we introduce a new methodology for diagnosis of DME using a novel set of features based on colour, wavelet decomposition and automatic lesion segmentation. These features are employed to train a classifier able to automatically diagnose DME through the presence of exudation. We present a new publicly available dataset with ground-truth data containing 169 patients from various ethnic groups and levels of DME. This and other two publicly available datasets are employed to evaluate our algorithm. We are able to achieve diagnosis performance comparable to retina experts on the MESSIDOR (an independently labelled dataset with 1200 images) with cross-dataset testing (e.g., the classifier was trained on an independent dataset and tested on MESSIDOR). Our algorithm obtained an AUC between 0.88 and 0.94 depending on the dataset/features used. Additionally, it does not need ground truth at lesion level to reject false positives and is computationally efficient, as it generates a diagnosis on an average of 4.4 s (9.3 s, considering the optic nerve localization) per image on an 2.6 GHz platform with an unoptimized Matlab implementation.

  1. The diagnostic value of pleural effusion ferritin and the ratio of it to serum ferritin in differentiating exudates from transudates

    International Nuclear Information System (INIS)

    To explore the diagnostic value of measuring the level of ferritin in pleural and peritoneal effusion for differentiating exudates from transudates, 128 effusion samples were initially detected for differentiating exudates from transudates by traditional method and Light's criteria. Ferritin in the effusions and serum ferritin were detected simultaneously, and the ratio of effusion ferritin (PFt) to serum ferritin (SFt) was counted. Based on the clinical data, the samples were divided into four groups and PFt and PFt/SFt were compared. At the same time, the sensitivity and specificity of PFt and PFt/SFt in differentiating exudates from transudates were compared with traditional method and Light's criteria. The results showed that in the groups of tuberculous pleurisy, non-tuberculous, benign pleurisy, and malignant tumor, the concentration of Ft in the effusions was significantly higher than that in the group of congestive heart failure and cirrhosis; and the Ft in exudates was significantly higher than that in transudates (P0.05). If the cut-off value was set up for Ft in the effusion as 100 μg/L and PFt/SFt ratio as 0.5, respectively, the differentiating sensitivity and specificity were 94.2% and 87.0%, respectively. Conclusion was that the concentration of PFt and PFt/SFt in exudates are higher than 100 μg/L and 0.5, respectively. On the contrary, they are lower than the cut-off level in transudates. PFt and PFt/SFt have high sensitivity and high specificity in differentiating exudates from transudates, and have great diagnostic value

  2. In situ stimulation vs. bioaugmentation: Can microbial inoculation of plant roots enhance biodegradation of organic compounds?

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, M.T.; Metting, F.B. Jr.; Fredrickson, J.K. [Pacific Northwest Lab., Richland, WA (United States); Seidler, R.J. [Environmental Protection Agency, Corvallis, OR (United States). Environmental Research Lab.

    1993-06-01

    The use of plant roots and their associated rhizosphere bacteria for biocontainment and biorestoration offers several advantages for treating soil-dispersed contaminants and for application to large land areas. Plant roots function as effective delivery systems, since root growth transports bacteria vertically and laterally along the root in the soil column (see [ 1,2]). Movement of microbes along roots and downward in the soil column can be enhanced via irrigation [1-4]. For example, Ciafardini et al. [3] increased the nodulation and the final yield of soybeans during pod filling by including Bradyrhizobium japonicum in the irrigation water. Using rhizosphere microorganisms is advantageous for biodegradation of compounds that are degraded mainly by cometabolic processes, e.g., trichloroethylene (TCE). The energy source for bacterial growth and metabolism is supplied by the plant in the form of root exudates and other sloughed organic material. Plants are inexpensive, and by careful choice of species that possess either tap or fibrous root growth patterns, they can be used to influence mass transport of soil contaminants to the root surface via the transpiration stream [5]. Cropping of plants to remove heavy metals from contaminated soils has been proposed as a viable, low-cost, low-input treatment option [6]. The interest in use of plants as a remediation strategy has even reached the popular press [7], where the use of ragweed for the reclamation of sites contaminated with tetraethyl lead and other heavy metals was discussed.

  3. X-ray computed tomography uncovers root-root interactions: quantifying spatial relationships between interacting root systems in three dimensions

    Directory of Open Access Journals (Sweden)

    Alexander Martin Paya

    2015-04-01

    Full Text Available Research in the field of plant biology has recently demonstrated that inter- and intra-specific interactions belowground can dramatically alter root growth. Our aim was to answer questions related to the effect of inter- vs. intra-specific interactions on the growth and utilization of undisturbed space by fine roots within three dimensions (3D using micro X-ray computed tomography. To achieve this, Populus tremuloides (quaking aspen and Picea mariana (black spruce seedlings were planted into containers as either solitary individuals, or inter-/intra-specific pairs, allowed to grow for two months, and 3D metrics developed in order to quantify their use of belowground space. In both aspen and spruce, inter-specific root interactions produced a shift in the vertical distribution of the root system volume, and deepened the average position of root tips when compared to intra-specifically growing seedlings. Inter-specific interactions also increased the minimum distance between root tips belonging to the same root system. There was no effect of belowground interactions on the radial distribution of roots, or the directionality of lateral root growth for either species. In conclusion, we found that significant differences were observed more often when comparing controls (solitary individuals and paired seedlings (inter- or intra-specific, than when comparing inter- and intra-specifically growing seedlings. This would indicate that competition between neighboring seedlings was more responsible for shifting fine root growth in both species than was neighbor identity. However, significant inter- vs. intra-specific differences were observed, which further emphasizes the importance of biological interactions in competition studies.

  4. Regulation of Root Length and Lateral Root Number in Trifoliate Orange Applied by Peroxide Hydrogen and Arbuscular Mycorrhizal Fungi

    OpenAIRE

    LIU, CHUN-YAN; Huang, Yong-Ming; Ying-Ning ZOU; Wu, Qiang-Sheng

    2014-01-01

    Root system morphology (RSM) in plants plays a key role in acquiring nutrients from the soil and is also altered by abiotic or biotic factors including soil microorganisms and signal molecules. The present study was made to evaluate the effects of an arbuscular mycorrhizal fungus (AMF, Glomus versiforme) and exogenous peroxide hydrogen (H2O2, 0, 1 and 100 μM) on root length, lateral root number and activities of polyamine-metabolized enzymes in trifoliate orange (Poncirus trifoliata) see...

  5. Combining the genetic algorithm and successive projection algorithm for the selection of feature wavelengths to evaluate exudative characteristics in frozen-thawed fish muscle.

    Science.gov (United States)

    Cheng, Jun-Hu; Sun, Da-Wen; Pu, Hongbin

    2016-04-15

    The potential use of feature wavelengths for predicting drip loss in grass carp fish, as affected by being frozen at -20°C for 24 h and thawed at 4°C for 1, 2, 4, and 6 days, was investigated. Hyperspectral images of frozen-thawed fish were obtained and their corresponding spectra were extracted. Least-squares support vector machine and multiple linear regression (MLR) models were established using five key wavelengths, selected by combining a genetic algorithm and successive projections algorithm, and this showed satisfactory performance in drip loss prediction. The MLR model with a determination coefficient of prediction (R(2)P) of 0.9258, and lower root mean square error estimated by a prediction (RMSEP) of 1.12%, was applied to transfer each pixel of the image and generate the distribution maps of exudation changes. The results confirmed that it is feasible to identify the feature wavelengths using variable selection methods and chemometric analysis for developing on-line multispectral imaging. PMID:26617027

  6. Using Square Roots

    Science.gov (United States)

    Wilson, William Wynne

    1976-01-01

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

  7. Evaluating the potential of a novel oral lesion exudate collection method coupled with mass spectrometry-based proteomics for oral cancer biomarker discovery

    Directory of Open Access Journals (Sweden)

    Kooren Joel A

    2011-09-01

    Full Text Available Abstract Introduction Early diagnosis of Oral Squamous Cell Carcinoma (OSCC increases the survival rate of oral cancer. For early diagnosis, molecular biomarkers contained in samples collected non-invasively and directly from at-risk oral premalignant lesions (OPMLs would be ideal. Methods In this pilot study we evaluated the potential of a novel method using commercial PerioPaper absorbent strips for non-invasive collection of oral lesion exudate material coupled with mass spectrometry-based proteomics for oral cancer biomarker discovery. Results Our evaluation focused on three core issues. First, using an "on-strip" processing method, we found that protein can be isolated from exudate samples in amounts compatible with large-scale mass spectrometry-based proteomic analysis. Second, we found that the OPML exudate proteome was distinct from that of whole saliva, while being similar to the OPML epithelial cell proteome, demonstrating the fidelity of our exudate collection method. Third, in a proof-of-principle study, we identified numerous, inflammation-associated proteins showing an expected increase in abundance in OPML exudates compared to healthy oral tissue exudates. These results demonstrate the feasibility of identifying differentially abundant proteins from exudate samples, which is essential for biomarker discovery studies. Conclusions Collectively, our findings demonstrate that our exudate collection method coupled with mass spectrometry-based proteomics has great potential for transforming OSCC biomarker discovery and clinical diagnostics assay development.

  8. WHY ROOTING FAILS.

    Energy Technology Data Exchange (ETDEWEB)

    CREUTZ,M.

    2007-07-30

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

  9. Root canal irrigation

    NARCIS (Netherlands)

    L. van der Sluis; C. Boutsioukis; L.M. Jiang; R. Macedo; B. Verhaagen; M. Versluis

    2015-01-01

    The aims of root canal irrigation are the chemical dissolution or disruption and the mechanical detachment of pulp tissue, dentin debris and smear layer (instrumentation products), microorganisms (planktonic or biofilm), and their products from the root canal wall, their removal out of the root cana

  10. The Root Canal Biofilm

    NARCIS (Netherlands)

    Sluis, van der L.W.M.; Boutsioukis, C.; Jiang, L.M.; Macedo, R.; Verhaagen, B.; Versluis, M.; Chávez de Paz, E.; Sedgley, C.M.; Kishen, A.

    2015-01-01

    The aims of root canal irrigation are the chemical dissolution or disruption and the mechanical detachment of pulp tissue, dentin debris and smear layer (instrumentation products), microorganisms (planktonic or biofilm), and their products from the root canal wall, their removal out of the root cana

  11. Conservative Management of Unset Mineral Trioxide Aggregate Root-End Filling: A Case Report.

    Science.gov (United States)

    Parirokh, Masoud; Farzaneh, Sedigheh; Hallajmofrad, Ali Reza

    2016-01-01

    This case report presents conservative management of unset mineral trioxide aggregate (MTA) after being placed as a root-end filling material following periapical surgery. Periapical surgery was indicated for a maxillary lateral incisor of a 15-year-old male due to persistent exudate and a large periapical lesion. During surgery Angelus MTA was placed as root-end filling. The next session it was noticed that MTA had failed to completely set. In an orthograde approach, calcium-enriched mixture (CEM) cement was used to obturate the root canal space. The patient was followed up for 27 months and did not exhibit any clinical signs and symptoms. Radiographic images showed complete healing of the lesion. PMID:27471540

  12. Balancing Water Uptake and Loss through the Coordinated Regulation of Stomatal and Root Development

    Science.gov (United States)

    Hepworth, Christopher; Turner, Carla; Landim, Marcela Guimaraes; Cameron, Duncan; Gray, Julie E.

    2016-01-01

    Root development is influenced by nutrient and water availabilities. Plants are able to adjust many attributes of their root in response to environmental signals including the size and shape of the primary root, lateral roots and root hairs. Here we investigated the response of roots to changes in the levels of leaf transpiration associated with altered stomatal frequency. We found that plants with high stomatal density and conductance produce a larger rooting area and as a result have enhanced phosphate uptake capacity whereas plants with low stomatal conductance produce a smaller root. Manipulating the growth environment of plants indicated that enhanced root growth is most likely a result of an increased demand for water rather than phosphate. Plants manipulated to have an increase or reduction in root hair growth show a reduction or increase respectively, in stomatal conductance and density. Our results demonstrate that plants can balance their water uptake and loss through coordinated regulation of both stomatal and root development. PMID:27275842

  13. The role of physical rehabilitation in the treatment of exudative pleurisy

    Directory of Open Access Journals (Sweden)

    Milojević Momir

    2004-01-01

    Full Text Available INTRODUCTION Exudates are due to a variety of diseases, the major and most common ones being tuberculosis, nonspecific inflammation and malignancy. They are usually treated conservatively, sometimes combined with surgery and physical treatment. Physical the-rapy includes positional exercises, breathing exercises and biostimulation. Aim of the study The study was aimed to find out the following: 1 Is lung function improved by physical therapy; 2 Can adhesions be diminished and mobility of the affected hemidiaphragm improved by physical treatment; 3 Is there a direct positive correlation between physical treatment and obtained improvement, or the same can be achieved in patients receiving medicamentous treatment only; 4 What are the effects of some factors we cannot influence (sex, age, effusion level, position of adhesions on lung function and diaphragm mobility improvement, that is on the efficiency of physical treatment; 5 How do the factors we can influence (the time interval before initiating the treatment and its duration affect improvement of the same lung function parameters, that is treatment efficacy? Material and methods Physical treatment of patients with exudative pleurisy was accomplished at the Department of Rehabilitation in our Institute and it consisted of directed breathing exercises and laser biostimulation. Its effects were examined in a group of 175 patients, who received both conservative and physical treatment, and results were compared with the control group patients, treated only conservatively (with antibiotics, antituberculotics, corticosteroids. RESULTS Comparative analysis confirmed a significant improvement of lung function parameters (VC, FEV1, PEF as well as of hemidiaphragm mobility on the affected side of the thorax in favour of the examined group. The severity of the lung function and diaphragm mobility impairments have been found to be in correlation with the localization of adhesions, whereas the degree of

  14. Differential inactivation of seed exudate stimulation of Pythium ultimum sporangium germination by Enterobacter cloacae influences biological control efficacy on different plant species.

    Science.gov (United States)

    Kageyama, Koji; Nelson, Eric B

    2003-02-01

    This study was initiated to understand whether differential biological control efficacy of Enterobacter cloacae on various plant species is due to differences in the ability of E. cloacae to inactivate the stimulatory activity of seed exudates to Pythium ultimum sporangium germination. In biological control assays, E. cloacae was effective in controlling Pythium damping-off when placed on the seeds of carrot, cotton, cucumber, lettuce, radish, tomato, and wheat but failed to protect corn and pea from damping-off. Seeds from plants such as corn and pea had high rates of exudation, whereas cotton and cucumber seeds had much lower rates of exudation. Patterns of seed exudation and the release of P. ultimum sporangium germination stimulants varied among the plants tested. Seed exudates of plants such as carrot, corn, lettuce, pea, radish, and wheat were generally more stimulatory to P. ultimum than were the exudates of cotton, cucumber, sunflower, and tomato. However, this was not directly related to the ability of E. cloacae to inactivate the stimulatory activity of the exudate and reduce P. ultimum sporangium germination. In the spermosphere, E. cloacae readily reduced the stimulatory activity of seed exudates from all plant species except corn and pea. Our data have shown that the inability of E. cloacae to protect corn and pea seeds from Pythium damping-off is directly related to its ability to inactivate the stimulatory activity of seed exudates. On all other plants tested, E. cloacae was effective in suppressing damping-off and inactivating the stimulatory activity of seed exudates. PMID:12571037

  15. Measurement of vancomycin hydrochloride concentration in the exudate from wounds receiving negative pressure wound therapy: a pilot study.

    Science.gov (United States)

    Ida, Yukiko; Matsumura, Hajime; Onishi, Masami; Ono, Sayaka; Imai, Ryutaro; Watanabe, Katsueki

    2016-04-01

    It has been reported that negative pressure wound therapy (NPWT) is effective in the treatment of contaminated wounds. We hypothesised that systemically administered antibiotics migrate to wound site effectively by NPWT, which provides the antibacterial effect. We measured and compared the concentrations of vancomycin in the exudate and blood serum. Eight patients with skin ulcers or skin defect wounds who were treated with NPWT and were administered an intravenous drip of vancomycin were enrolled in this study. The wound surfaces were muscle, muscle fascia or adipose tissue. We administered vancomycin intravenously to NPWT patients (1-3 g/day). The exudate was obtained using 500 ml V.A.C. ATS canisters without gel. Three days later, the concentrations of vancomycin were measured. The mean concentration of vancomycin in the exudate from NPWT was 67% of the serum vancomycin concentration. We found that concentrations of vancomycin in NPWT exudates are higher than the previously reported concentrations in soft tissue without NPWT. The proactive use of NPWT might be considered in cases of suspected wound contamination when a systemic antibiotic is administered. PMID:24674131

  16. Evaluation of colloidal radioactive chromium phosphate retention in the articular exudates

    International Nuclear Information System (INIS)

    Isotope measurements were carried out in patients receiving intra-articular injection of colloidal solution of radioactive chromium phosphate for chronic synovial exudates in knee joints. The degree of isotope escape outside the joint and its accumulation in the inguinal lymph nodes and liver were evaluated. Twenty-three joints were studied, in 9 cases some escape of the isotope from the joint and absence of accumulation in lymph nodes was observed. In the remaining 14 cases the accumulation in lymph nodes was observed, in 12 of them the amount of isotope was below 1% of the administered dose, in 2 cases was about 2%. In these cases the amount of the isotope escaping from the joint was from several to over ten per cent. In one case some accumulation of the isotope was observed also in the liver. (author)

  17. Multimodal imaging of exudative maculopathy associated with hand-foot-mouth disease.

    Science.gov (United States)

    Vaz-Pereira, Sara; Macedo, Mafalda; De Salvo, Gabriella; Pal, Bishwanath

    2014-01-01

    A 31-year-old man presented with acute unilateral visual loss secondary to hand-foot-mouth disease (HFMD). Ophthalmic examination demonstrated best corrected visual acuity (BCVA) of 6/24 and a macular neurosensory detachment. He was diagnosed with unilateral acute idiopathic maculopathy (UAIM), and multimodality imaging was performed. No treatment was warranted. At 3 months, BCVA was 6/5 and funduscopy revealed a juxtafoveal scar. Based on the evidence of the association between HFMD and UAIM, the authors refer to this condition as exudative maculopathy associated with HFMD. Multimodality imaging during acute and convalescent phases is useful to study this disorder and raises questions about choroidal and bilateral involvement. Ophthalmologists should be aware of this and query about systemic signs and symptoms. PMID:24695047

  18. A case of neurosyphilis revealed by acute exudative polymorphous vitelliform maculopathy.

    Science.gov (United States)

    Wolff, Benjamin; Mrejen, Sarah; Freund, K Bailey; Titah, Cherif; Mauget-Faÿsse, Martine

    2014-01-01

    The authors report the case of a healthy 56-year-old man presenting with bilateral vision loss. Clinical features were consistent with the diagnosis of acute exudative polymorphous vitelliform maculopathy (AEPVM). The patient returned 10 days later with bilateral anterior granulomatous uveitis, and the inflammatory work-up revealed treponemal antibodies in the serum and spinal fluid, consistent with a diagnosis of active neurosyphilis. The patient received standard treatment for neurosyphilis with intravenous penicillin G. Two months later, the intraocular inflammation had resolved, but the resolution of the vitelliform lesions was more gradual. An immune process could be a plausible explanation for these clinical findings. Clinicians should be aware that syphilis can produce AEPVM. PMID:24695048

  19. Optical Coherence Tomography Findings of the Acute Exudative Polymorphous Vitelliform Maculopathy.

    Science.gov (United States)

    Brasil, Oswaldo Ferreira Moura; Vianna, Raul Nunes Galvarro; Moraes, Remo Turchetti

    2010-03-01

    The optical coherence tomography (OCT) findings of a 26-year-old HIV-positive male with acute exudative polymorphous vitelliform maculopathy were described. His with best-corrected visual acuity at the presentation of the disease was 20/25 in the right eye and 20/30 in the left eye. Fundus examination showed bilateral yellowish subretinal lesions arranged in a honeycombed pattern throughout the posterior pole in both eyes. OCT scans on the topography of these lesions showed well-defined hyporeflective spaces that occasionally merged, limited superiorly by the retinal pigment epithelium and inferiorly by a hypereflective tissue that could correspond to Bruch's membrane. Sub-sensory fluid was found in both maculas. PMID:20337319

  20. PENGGUNAAN GETAH PEPAYA DALAM SINTESIS ESTER XILITOL ASAM LEMAK (EXAL [The Use of Papaya Exudates for Fatty Acid Xilitol Synthesis

    Directory of Open Access Journals (Sweden)

    Suhardi

    2003-12-01

    Full Text Available Fatty acid xylitol-ester (FAXILE are xylitol esters of fatty acids with one to five DE (degree of esterification value. FAXILE with DE value of 3 or higher can be used as low calorie fat replacer since they have low digestive property; while the xylitol ester with DE of less than 3 can be used as emulsifier. The FAXILE synthesis experiments were carried out by esterification of xylitol with palm oil¡¦s fatty acid (POFA using papaya exudates as a lipase source. The objective of this experiment was to evaluate the potential of papaya exuadates for the synthesis of FAXILE. In this first experiment, test were carried out to determine hydrolytic activity of lipases obtained from different part of papaya plant. The test, were performed with the presence of CaO and under different pH value. The papaya exudates were used for FAXILE synthesis under an optimum condition obtained from the first experiment. Samples were drawn during incubation at 40„aC for 1,2,3, and 4 days and hydroxyl number was analyzed to confirm the ester formation. The results showed that the most active exudate was from papaya leaves, followed by exudates from fruit with hydrolytic activity of 653 and 296 ƒÝmol/g. minutes, respectively. The hydrolytic activity of the fruit exudate was optimum at pH 6.0, at 45-50„aC, with the addition of CaO 4% dry exudates. The FAXILE synthesis with acid of papaya exudates was optimum at pH 6.0, at 45„aC with molar ratio of xylitol: fatty acids was 1 to 6,3 days incubation. At this condition the conversion rate xylitol to FAXILE was 79%.

  1. Smectite alteration

    International Nuclear Information System (INIS)

    This report contains the proceedings of a second workshop in Washington DC December 8-9, 1983 on the alteration of smectites intended for use as buffer materials in the long-term containment of nuclear wastes. It includes extended summaries of all presentations and a transcript of the detailed scientific discussion. The discussions centered on three main questions: What is the prerequisite for and what is the precise mechanism by which smectite clays may be altered to illite. What are likly sources of potassium with respect to the KBS project. Is it likely that the conversion of smectite to illite will be of importance in the 10 5 to the 10 6 year time frame. The workshop was convened to review considerations and conclusions in connection to these questions and also to broaden the discussion to consider the use of smectite clays as buffer materials for similar applications in different geographical and geological settings. SKBF/KBS technical report 83-03 contains the proceedings from the first workshop on these matters that was held at the State University of New York, Buffalo May 26-27, 1982. (Author)

  2. Combined intravitreal bevacizumab with phacoemulsification in visually significant cataract and visually significant exudative maculopathy

    Directory of Open Access Journals (Sweden)

    Ahmad Mansour

    2011-01-01

    Full Text Available Purpose : We investigated the visual outcome of combined phacoemulsification with intravitreal bevacizumab, in eyes with dense cataract and visually significant exudative maculopathy. Materials and Methods : Prospective longitudinal pilot study of consecutive patients treated by two surgeons in 2006, using intravitreal bevacizumab at the end of phacoemulsification. The historical control group consisted of consecutive subjects with exudative maculopathy and dense cataract treated by the same surgeons with the help of phacoemulsification without intravitreal bevacizumab prior to 2006. Results : Thirty-one treated patients had the mean (SD logMar best corrected visual acuity improving from - 1.48 (0.50 preoperatively to - 0.67 (0.38 in the first postoperative week ( p < 0.001, to - 0.64 (0.40 in the first postoperative month ( p < 0.001, and to - 0.62 (0.42 ( p < 0.001 on the last follow-up (mean 4.2 months, range 1 - 9 months. Fourteen control patients had the mean (SD logMar best corrected visual acuity improving from - 1.78 (0.79 preoperatively, to - 0.91 (0.53 in the first postoperative week ( p < 0.001, to - 0.86 (0.45 in the first postoperative month ( p < 0.001, and to - 0.90 (0.47 ( p < 0.001 on the last follow- up (mean 19.6 months, range 1 - 49 months. Initial visual acuities, final visual acuities, and percentage of visual improvement at one month were all not significantly better in the intervention compared to the control group at one month. In the study group, the fovea was flattened at the one-month follow-up, by 90-diopter slit lamp examination and / or Optical coherence tomography. Conclusion : The combination of intravitreal bevacizumab and phacoemulsification is beneficial for maximal visual rehabilitation in the first postoperative month.

  3. Functional properties of PSE (Pale, Soft, Exudative broiler meat in the production of mortadella

    Directory of Open Access Journals (Sweden)

    Cassiana Kissel

    2009-11-01

    Full Text Available This work was carried out in order to evaluate whether the functional properties of broiler meat are affected by the factors that lead to PSE (Pale, Soft, Exudative. PSE meat was characterized by pH and L* values, and mortadella formulations consisted of isolated soy protein, sodium tripolyphosphate, and cassava starch in addition to PSE and normal meats. The functionality of the meat was evaluated by examining the water holding capacity (WHC, texture profile, emulsion stability (ES and color of the final products. The results show that in mortadella prepared with PSE meat, the protein denaturation affected the ES. Additives are necessary to enhance the functional properties of PSE meat.Este trabalho foi realizado para avaliar o efeito dos fatores que conduzem à formação das carnes PSE (Pale, Soft, Exudative sobre as propriedades funcionais da carne de frango. Carnes PSE foram caracterizadas pelos valores de pH e L* e as formulações da mortadela consistiram de proteina isolada de soja, trifosfato de sódio, amido de mandioca e a adição das carnes normal e PSE. A funcionalidade da carne foi avaliada medindo a capacidade de retenção de água (CRA, perfil de textura, estabilidade de emulsão (EE, e cor dos produtos finais. Os resultados mostraram que na mortadela preparada com carnes PSE, as proteinas desnaturadas afetaram a EE. Aditivos são necessários para potencializar as propriedades funcionais da carne PSE.

  4. Net production and consumption of fluorescent colored dissolved organic matter by natural bacterial assemblages growing on marine phytoplankton exudates.

    Science.gov (United States)

    Romera-Castillo, Cristina; Sarmento, Hugo; Alvarez-Salgado, Xosé Antón; Gasol, Josep M; Marrasé, Celia

    2011-11-01

    An understanding of the distribution of colored dissolved organic matter (CDOM) in the oceans and its role in the global carbon cycle requires a better knowledge of the colored materials produced and consumed by marine phytoplankton and bacteria. In this work, we examined the net uptake and release of CDOM by a natural bacterial community growing on DOM derived from four phytoplankton species cultured under axenic conditions. Fluorescent humic-like substances exuded by phytoplankton (excitation/emission [Ex/Em] wavelength, 310 nm/392 nm; Coble's peak M) were utilized by bacteria in different proportions depending on the phytoplankton species of origin. Furthermore, bacteria produced humic-like substances that fluoresce at an Ex/Em wavelength of 340 nm/440 nm (Coble's peak C). Differences were also observed in the Ex/Em wavelengths of the protein-like materials (Coble's peak T) produced by phytoplankton and bacteria. The induced fluorescent emission of CDOM produced by prokaryotes was an order of magnitude higher than that of CDOM produced by eukaryotes. We have also examined the final compositions of the bacterial communities growing on the exudates, which differed markedly depending on the phytoplankton species of origin. Alteromonas and Roseobacter were dominant during all the incubations on Chaetoceros sp. and Prorocentrum minimum exudates, respectively. Alteromonas was the dominant group growing on Skeletonema costatum exudates during the exponential growth phase, but it was replaced by Roseobacter afterwards. On Micromonas pusilla exudates, Roseobacter was replaced by Bacteroidetes after the exponential growth phase. Our work shows that fluorescence excitation-emission matrices of CDOM can be a helpful tool for the identification of microbial sources of DOM in the marine environment, but further studies are necessary to explore the association of particular bacterial groups with specific fluorophores. PMID:21742918

  5. Root signals that mediate mutualistic interactions in the rhizosphere.

    Science.gov (United States)

    Rasmann, Sergio; Turlings, Ted Cj

    2016-08-01

    A recent boom in research on belowground ecology is rapidly revealing a multitude of fascinating interactions, in particular in the rhizosphere. Many of these interactions are mediated by photo-assimilates that are excreted by plant roots. Root exudates are not mere waste products, but serve numerous functions to control abiotic and biotic processes. These functions range from changing the chemical and physical properties of the soil, inhibiting the growth of competing plants, combatting herbivores, and regulating the microbial community. Particularly intriguing are root-released compounds that have evolved to serve mutualistic interactions with soil-dwelling organisms. These mutually beneficial plant-mediated signals are not only of fundamental ecological interest, but also exceedingly important from an agronomical perspective. Here, we attempt to provide an overview of the plant-produced compounds that have so far been implicated in mutualistic interactions. We propose that these mutualistic signals may have evolved from chemical defenses and we point out that they can be (mis)used by specialized pathogens and herbivores. We speculate that many more signals and interactions remain to be uncovered and that a good understanding of the mechanisms and ecological implications can be the basis for exploitation and manipulation of the signals for crop improvement and protection. PMID:27393937

  6. Genetic association among root morphology, root quality and root yield in ashwagandha (Withania somnifera)

    OpenAIRE

    Kumar Ramesh R.; Reddy Anjaneya Prasanna L.; Subbaiah Chinna J.; Kumar Niranjana A.; Prasad Nagendra H.N.; Bhukya Balakishan

    2011-01-01

    Ashwagandha (Withania somnifera) is a dryland medicinal crop and roots are used as valuable drug in traditional systems of medicine. Morphological variants (morphotypes) and the parental populations were evaluated for root - morphometric, quality and yield traits to study genetic association among them. Root morphometric traits (root length, root diameter, number of secondary roots/ plant) and crude fiber content exhibited strong association among them and ...

  7. Root canal irrigants

    Directory of Open Access Journals (Sweden)

    Kandaswamy Deivanayagam

    2010-01-01

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

  8. Evaluation and Selection of Common Bean (Phaseolus Vulgaris L.) Genotypes for Root Traits Associated with Phosphorus (P) Acquisition Efficiency and the Use of 32P Isotope in Studies on P Uptake by Root Hairs

    International Nuclear Information System (INIS)

    the plant tissue among contrasting genotypes showed that long root hair genotypes had greater 32P uptake compared with short root hair genotypes. In addition, a strong positive correlation (R2 = 0.8703) was observed between specific activity of 32P plant tissue and shoot dry weight of the four genotypes contrasting for root hairs. These results suggests that (a) a genotype can exhibit one or more root traits responsible for P uptake efficiency; (b) long root hairs increase total P uptake by releasing organic compounds (root exudates) that could help to solubilize P otherwise not readily available to inefficient genotypes with short root hairs. (author)

  9. Roots and routes

    DEFF Research Database (Denmark)

    Christensen, Ann-Dorte; Jensen, Sune Qvotrup

    2011-01-01

    arguing that there is a dynamic interplay between roots and routes in people's lives. The empirical point of departure is narratives about roots and routes by ethnic minorities settled in Aalborg East, an underprivileged neighbourhood in northern Denmark. One of the main findings is a gap between the...... somewhat paradoxical finding is that it appears to be more difficult for transnational migrants to maintain their roots in the country of origin when they go back than it was to establish new roots in the host country...

  10. Roots of Dehn twists

    OpenAIRE

    McCullough, Darryl; Rajeevsarathy, Kashyap

    2009-01-01

    D. Margalit and S. Schleimer found examples of roots of the Dehn twist about a nonseparating curve in a closed orientable surface, that is, homeomorphisms whose nth power is isotopic to the Dehn twist. Our main theorem gives elementary number-theoretic conditions that describe the values of n for which an nth root exists, given the genus of the surface. Among its applications, we show that n must be odd, that the Margalit-Schleimer roots achieve the maximum value of n among the roots for a gi...

  11. Highly Potent Extracts from Pea (Pisum sativum) and Maize (Zea mays) Roots Can Be Used to Induce Quiescence in Entomopathogenic Nematodes.

    Science.gov (United States)

    Jaffuel, Geoffrey; Hiltpold, Ivan; Turlings, Ted C J

    2015-09-01

    Root exudates can play an important role in plant-nematode interactions. Recent studies have shown that the root cap exudates obtained from several plant species trigger a state of dormancy or quiescence in various genera of nematodes. This phenomenon is not only of fundamental ecological interest, but also has application potential if the plant-produced compound(s) could be used to control harmful nematodes or help to prolong the shelf-life of beneficial entomopathogenic nematodes (EPNs). The identification of the compound(s) involved in quiescence induction has proven to be a major challenge and requires large amounts of active material. Here, we present a high-throughput method to obtain bioactive root extracts from flash-frozen root caps of green pea and maize. The root cap extract obtained via this method was considerably more potent in inducing quiescence than exudate obtained by a previously used method, and consistently induced quiescence in the EPN Heterorhabditis megidis, even after a 30-fold dilution. Extracts obtained from the rest of the root were equally effective in inducing quiescence. Infective juveniles (IJs) of H. megidis exposed to these extracts readily recovered from their quiescent state as soon as they were placed in moist soil, and they were at least as infectious as the IJs that had been stored in water. Excessive exposure of IJs to air interfered with the triggering of quiescence. The implications of these results and the next steps towards identification of the quiescence-inducing compound(s) are discussed from the perspective of applying EPN against soil-dwelling insect pests. PMID:26364294

  12. Improvement of Root System Architecture in Peach (Prunus persica Seedlings by Arbuscular Mycorrhizal Fungi, Related to Allocation of Glucose/Sucrose to Root

    Directory of Open Access Journals (Sweden)

    Qiang-Sheng WU

    2011-11-01

    Full Text Available Root system architecture (RSA is used to describe the spatial configuration of a root system in the soil, which substantially determines the capacity of a plant to take up nutrients and water. The present study was to assess if arbuscular mycorrhizal fungi (AMF, Glomus mosseae, G. versiforme, and Paraglomus occultum would alter RSA of peach (Prunus persica L. Batsch seedlings, and the alteration due to mycorrhization was related to allocation of glucose/sucrose to root (Aglucose/sucrose. Inoculation with G. mosseae and G. versiforme significantly increased leaf, stem, root and total fresh weights, compared with non-AMF treatment. Mycorrhizal alterations of RSA in peach plants were dependent on AMF species, because only G. mosseae and G. versiforme but not P. occultum markedly increased root length, root projected area, root surface area and root volume. For the distribution of root length classes, AMF mainly increased 0-1 and 3-4 cm root length classes, which is AMF species dependent. Inoculated seedlings with Glomus species recorded significantly higher root sucrose and leaf and root glucose concentrations and lower root sucrose concentrations than un-inoculated control. Compared with the non-AMF treatment, G. mosseae and G. versiforme generally increased the Aglucose and Asucrose, but P. occultum significantly decreased the Aglucose and Asucrose. Asucrose or Aglucose was significantly positive correlated with root length, root projected area and root surface area. The results suggest that AMF modified variables of RSA in peach, which is AMF species dependent and related to Aglucose and Asucrose.

  13. Genetic Improvement of Root Growth Contributes to Efficient Phosphorus Acquisition in maize (Zea mays L.)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-kai; CHEN Fan-jun; CHEN Xiao-chao; LONG Li-zhi; GAO Kun; YUAN Li-xing; ZHANG Fu-suo; MI Guo-hua

    2013-01-01

    Maize plants adapt to low phosphorus (P) stress by increasing root growth. It is of importance to know the extent to which genetic improvement of root growth can enhance P acquisiton. In the present study, the contribution of root growth improvement to efficient P acquisition was evaluated in two soils using T149 and T222, a pair of near isogenic maize testcrosses which were derived from a backcross BC4F3 population. T149 and T222 showed no difference in shoot biomass and leaf area under normal growth conditions, but differed greatly in root growth. T149 had longer lateral roots and a larger root surface area compared to T222. In calcareous soil, when P was insufficient, i.e., when P was either supplied as KH2PO4 at a concentration of 50 mg P kg-1 soil, or in the form of Phy-P, Ca3-P or Ca10-P, a 43%increase in root length in T149 compared to T222 resulted in an increase in P uptake by 53%, and shoot biomass by 48%. In acid soil, however, when P supply was insufficient, i.e., when P was supplied as KH2PO4 at a concentration of 100 mg P kg-1 soil, or in the form of Phy-P, Fe-P or Al-P, a 32%increase in root length in T149 compared to T222 resulted in an increase in P uptake by only 12%, and shoot biomass by 7%. No significant differences in the exudation of organic acids and APase activity were found between the two genotypes. It is concluded that genetic improvement of root growth can efficiently increase P acquisition in calcareous soils. In acid soils, however, improvements in the physiological traits of roots, in addition to their size, seem to be required for efficient P acquisition.

  14. Microbial antagonism as a potential solution for controlling selected root pathogens of crops

    Science.gov (United States)

    Cooper, Sarah; Agnew, Linda; Pereg, Lily

    2016-04-01

    Root pathogens of crops can cause large reduction in yield, however, there is a limited range of effective methods to control such pathogens. Soilborne pathogens that infect roots often need to survive in the rhizosphere, where there is high competition from other organisms. In such hot spots of microbial activity and growth, supported by root exudates, microbes have evolved antagonistic mechanisms that give them competitive advantages in winning the limited resources. Among these mechanisms is antibiosis, with production of some significant antifungal compounds including, antibiotics, volatile organic compounds, hydrogen cyanide and lytic enzymes. Some of these mechanisms may suppress disease through controlling the growth of root pathogens. In this project we isolated various fungi and bacteria that suppress the growth of cotton pathogens in vitro. The pathogen-suppressive microbes were isolated from cotton production soils that are under different management strategies, with and without the use of organic amendments. The potential of pathogen-suppressing microbes for controlling the black root rot disease, caused by the soilborne pathogen Thielaviopsis basicola, was confirmed using soil assays. We identified isolates with potential use as inoculant for cotton production in Australia. Having isolated a diverse group of antagonistic microbes enhances the probability that some would survive well in the soil and provide an alternative approach to address the problem of root disease affecting agricultural crops.

  15. Visual outcome of intravitreal ranibizumab for exudative age-related macular degeneration: timing and prognosis

    Directory of Open Access Journals (Sweden)

    Canan H

    2014-01-01

    Full Text Available Handan Canan,1 Selçuk Sizmaz,2 Rana Altan-Yaycioğlu,1 Çağla Saritürk,3 Gürsel Yilmaz41Department of Ophthalmology, Adana Teaching and Medical Research Center, Baskent University School of Medicine, 2Department of Ophthalmology, Çukurova University School of Medicine, 3Department of Biostatistics, Adana Teaching and Medical Research Center, Baskent University School of Medicine, 4Department of Ophthalmology, Baskent University School of Medicine, Ankara, TurkeyPurpose: To describe 1-year clinical results of intravitreal ranibizumab treatment in patients with choroidal neovascularization secondary to exudative age-related macular degeneration (AMD and to evaluate whether early treatment is a predictive value for prognosis of the disease.Materials and methods: Clinical records were retrospectively reviewed of 104 eyes that underwent intravitreal ranibizumab therapy for exudative AMD. Patients were divided into two groups according to their symptom duration: group 1, <1 month; and group 2, 1–3 months. After three monthly injections, patients were examined monthly, and subsequent injections were performed as needed.Results: There were 43 female (48.9% and 45 males (51.1%. The follow-up time was 13.7±1.9 (12–19 months. The mean logarithm of minimum angle of resolution best-corrected visual acuity (BCVA improved significantly, from 0.45±0.639 at baseline to 0.08±0.267 at 12 months in group 1, and from 1.06±0.687 at baseline to 0.75±0.563 at 12 months in group 2. The increase in BCVA was statistically significant in group 1 (P=0.009. The mean central retinal thickness (CRT decreased significantly, from 355.13±119.93 µm at baseline to 250.85±45.48 µm at 12 months in group 1, and from 371.88±91.047 µm at baseline to 268.61±53.51 µm at 12 months in group 2. The decrease in CRT was statistically significant in group 1 (P=0.001.Conclusion: Intravitreal ranibizumab therapy was effective in significantly increasing mean BVCA and

  16. Identifying root system genes using induced mutants in barley

    International Nuclear Information System (INIS)

    Root systems play an important role in plant growth and development. They absorb water and nutrients, anchor plant in the soil and affect plant tolerance to various abiotic stresses. Despite their importance, the progress in understanding the molecular processes underlying root development has been achieved only in Arabidopsis thaliana. It was accomplished through detailed analysis of root mutants with the use of advanced molecular, genomic and bioinformatic tools. Recently, similar studies performed with rice and maize root mutants have led to the identification of homologous and novel genes controlling root system formation in monocots. The collection of barley mutants with changes in root system development and morphology has been developed in our Department after mutagenic treatments of spring barley varieties with N-methyl N-nitosourea (MNU) and sodium azide. Among these mutants, the majority was characterized by seminal roots significantly shorter than roots of a parent variety throughout a whole vegetation period. Additionally, several mutants with root hairs impaired at different stages of development have been identified. These mutants have become the material of studies aimed at genetic and molecular dissection of seminal root and root hair formation in barley. The studies included the molecular mapping of genes responsible for mutant phenotype using DNA markers and root transcriptome analysis in the mutant/parent variety system. Using cDNA RDA approach, we have identified the HvEXPB1 gene encoding root specific beta expansin related to the root hair initiation in barley. We have also initiated the database search for barley sequences homologous to the known Arabodopsis, maize and rice genes. The identified homologous ESTs are now used for isolation of the complete coding sequences and gene function will be validated through identification of mutations related to the altered phenotype. This work was supported by the IAEA Research Contracts 12611 and 12849

  17. Chromatic roots and hamiltonian paths

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2000-01-01

    We present a new connection between colorings and hamiltonian paths: If the chromatic polynomial of a graph has a noninteger root less than or equal to t(n) = 2/3 + 1/3 (3)root (26 + 6 root (33)) + 1/3 (3)root (26 - 6 root (33)) = 1.29559.... then the graph has no hamiltonian path. This result is...

  18. Application of a modified EDTA-mediated exudation technique and guttation fluid analysis for Potato spindle tuber viroid RNA detection in tomato plants (Solanum lycopersicum).

    Science.gov (United States)

    Kovalskaya, Natalia; Owens, Robert; Baker, C Jacyn; Deahl, Kenneth; Hammond, Rosemarie W

    2014-03-01

    Potato spindle tuber viroid (PSTVd) is a small plant pathogenic circular RNA that does not encode proteins, replicates autonomously, and traffics systemically in infected plants. Long-distance transport occurs by way of the phloem; however, one report in the literature describes the presence of viroid RNA in the xylem ring of potato tubers. In this study, a modified method based on an EDTA-mediated phloem exudation technique was applied for detection of PSTVd in the phloem of infected tomato plants. RT-PCR, nucleic acid sequencing, and Southern blot analyses of RT-PCR products verified the presence of viroid RNA in phloem exudates. In addition, the guttation fluid collected from the leaves of PSTVd-infected tomato plants was analyzed revealing the absence of viroid RNA in the xylem sap. To our knowledge, this is the first report of PSTVd RNA detection in phloem exudates obtained by the EDTA-mediated exudation technique. PMID:24388932

  19. Intravitreal treatment in patients with exudative age-related macular degeneration and visual acuity ≤ 0.05

    OpenAIRE

    Koch, Raphael; Schmidt, Matthias; Gebauer, Sabine; Busse, Holger; Uhlig, Constantin E.

    2015-01-01

    Background To investigate intravitreal treatment efficiencies in patients suffering from exudative ARMD with a BCVA ≤ 0.05. Methods Retrospective analysis: Analysis parameters were lesion type, BCVA at baseline and at follow-up, the intravitreal drug used, and its application frequency. Patients were divided into: 1) following injections of bevacizumab, triamcinolone, their combination, or ranibizumab regardless of their lesion subtype, 2) or by lesion subtype. Statistical tests were performe...

  20. Detection of Babesia annae DNA in lung exudate samples from Red foxes (Vulpes vulpes) in Great Britain

    OpenAIRE

    Bartley, Paul M; Hamilton, Clare; Wilson, Cari; Innes, Elisabeth A; Katzer, Frank

    2016-01-01

    Background This study aimed to determine the prevalence of Babesia species DNA in lung exudate samples collected from red foxes (Vulpes vulpes) from across Great Britain. Babesia are small piroplasmid parasites which are mainly transmitted through the bite of infected ticks of the family Ixodidae. Babesia can cause potentially fatal disease in a wide-range of mammalian species including humans, dogs and cattle, making them of significant economic importance to both the medical and veterinary ...

  1. Improving transport container design to reduce broiler chicken PSE (pale, soft, exudative) meat in Brazil.

    Science.gov (United States)

    Spurio, Rafael S; Soares, Adriana L; Carvalho, Rafael H; Silveira Junior, Vivaldo; Grespan, Moisés; Oba, Alexandre; Shimokomaki, Massami

    2016-02-01

    Throughout the chicken production chain, transport from farm to the commercial abattoir is one of the most critical sources of stress, particularly heat stress. The aim of this work was to describe the performance of a new prototype truck container designed to improve the microenvironment and reduce the incidence of pale, soft and exudative (PSE) meat and dead on arrival (DOA) occurrences. Experiments were carried out for four different conditions: regular and prototype truck, both with and without wetting loaded cages at the farm (for bird thermal stress relief) just before transporting. While there was no difference in the DOA index (P ≥ 0.05), the prototype truck caused a reduction (P < 0.05) in the occurrence of PSE meat by 66.3% and 49.6% with and without wetting, respectively. The results of this experiment clearly revealed a low-cost solution for transporting chickens that yields better animal welfare conditions and improves meat quality. PMID:26304672

  2. The past, present, and future of exudative age-related macular degeneration treatment

    Directory of Open Access Journals (Sweden)

    Yoreh Barak

    2012-01-01

    Full Text Available Treatment of exudative age-related macular degeneration has been revolutionized within the last 6 years with the introduction of vascular endothelial growth factor neutralizing agents. Previously popular "destructive treatments," such as laser photocoagulation and photodynamic treatment have either been abandoned or used as an adjunct to pharmacotherapy. Despite the increase in vision after antivascular endothelial growth factor (VEGF agents, they require repetitive and costly intravitreal injections that also carry the inherit risks of infection, retinal tears, and detachment. Several new and more potent VEGF inhibitors are at different stages of development. The goal of evolving pharmacotherapy is to preserve the therapeutic effect while reducing or eliminating the discomfort of intravitreal drug delivery, as well as identify new therapeutic targets. Complement inhibitors, immunomodulators, integrin inhibitors are a few of the new class of drugs that are expected to be in our armamentarium soon. Current medications act to decrease leakage through abnormal subretinal choroidal vasculature and promote involution. However, these medications are only effective in treating the active stage of the choroidal neovascular membrane. Restoration of vision of a large number of patients with involuted choroidal neovascular membranes is warranted. For this purpose, tissue engineering techniques have been employed to reconstruct the subretinal anatomy. Discovery of biomarkers, pharmacogenetics, and very specific targeting holds the promise of increased potency and safety in the future.

  3. Some physico-chemical properties of Prunus armeniaca L. gum exudates.

    Science.gov (United States)

    Fathi, Morteza; Mohebbi, Mohebbat; Koocheki, Arash

    2016-01-01

    The objectives of this paper were to investigate some physicochemical properties of Prunus armeniaca L. gum exudates (PAGE). PAGE had, on average, 66.89% carbohydrate, 10.47% uronic acids, 6.9% moisture (w.b.), 2.91% protein, 4% ash and 1.59% fat. PAGE was composed of monosaccharides including l-arabinose, d-galactose, xylose, mannose and rhamnose in molar percentages of 41.52%, 23.72%, 17.82%, 14.40% and 2.54%, respectively. Elemental analysis showed that PAGE had high values of nutrients. FTIR analysis demonstrated the presence of carboxyl, hydroxyl and methyl groups and glycoside bonds. The weight average molecular weight, number average molecular weight and polydispersity index were found to be approximately 5.69 × 10(5)g/mol, 4.33 g/mol and 1.31, respectively. Rheological measurement of PAGE solutions as a function of concentration (8, 10 and 12% (w/w)) and temperature (10, 20, 30 and 40°C) demonstrated that the gum solutions had a non Newtonian shear thinning behaviour. Intrinsic viscosity for PAGE in deionized water was 3.438 dl/g based on Kramer equation. PMID:26434520

  4. Phloem-exudate proteome analysis of response to insect brown plant-hopper in rice.

    Science.gov (United States)

    Du, Ba; Wei, Zhe; Wang, Zhanqi; Wang, Xiaoxiao; Peng, Xinxin; Du, Bo; Chen, Rongzhi; Zhu, Lili; He, Guangcun

    2015-07-01

    Brown plant-hopper (Nilaparvata lugens Stål, BPH), one of the most devastating agricultural insect pests of rice throughout Asia, ingests nutrients from rice sieve tubes and causes a dramatic yield loss. Planting resistant variety is an efficient and economical way to control this pest. Understanding the mechanisms of host resistance is extremely valuable for molecular design of resistant rice variety. Here, we used an iTRAQ-based quantitative proteomics approach to perform analysis of protein expression profiles in the phloem exudates of BPH-resistant and susceptible rice plants following BPH infestation. A total of 238 proteins were identified, most of which were previously described to be present in the phloem of rice and other plants. The expression of genes for selected proteins was confirmed using a laser capture micro-dissection method and RT-PCR. The mRNAs for three proteins, RGAP, TCTP, and TRXH, were further analyzed by using in situ mRNA hybridization and localized in the phloem cells. Our results showed that BPH feeding induced significant changes in the abundance of proteins in phloem sap of rice involved in multiple pathways, including defense signal transduction, redox regulation, and carbohydrate and protein metabolism, as well as cell structural proteins. The results presented provide new insights into rice resistance mechanisms and should facilitate the breeding of novel elite BPH-resistant rice varieties. PMID:26072143

  5. Prosopis alba exudate gum as excipient for improving fish oil stability in alginate-chitosan beads.

    Science.gov (United States)

    Vasile, Franco Emanuel; Romero, Ana María; Judis, María Alicia; Mazzobre, María Florencia

    2016-01-01

    The aim of the present work was to employ an exudate gum obtained from a South American wild tree (Prosopis alba), as wall material component to enhance the oxidative stability of fish oil encapsulated in alginate-chitosan beads. For this purpose, beads were vacuum-dried and stored under controlled conditions. Oxidation products, fatty acid profiles and lipid health indices were measured during storage. Alginate-chitosan interactions and the effect of gum were manifested in the FT-IR spectra. The inclusion of the gum in the gelation media allowed decreasing the oxidative damage during storage in comparison to the free oil and alginate-chitosan beads. The gum also improved wall material properties, providing higher oil retention during the drying step and subsequent storage. Fatty acids quality and lipid health indices were widely preserved in beads containing the gum. Present results showed a positive influence of the gum on oil encapsulation and stability, being the main mechanism attributed to a physical barrier effect. PMID:26213081

  6. Identification of novel KIF11 mutations in patients with familial exudative vitreoretinopathy and a phenotypic analysis.

    Science.gov (United States)

    Li, Jia-Kai; Fei, Ping; Li, Yian; Huang, Qiu-Jing; Zhang, Qi; Zhang, Xiang; Rao, Yu-Qing; Li, Jing; Zhao, Peiquan

    2016-01-01

    KIF11 gene mutations cause a rare autosomal dominant inheritable disease called microcephaly with or without chorioretinopathy, lymphedema, or mental retardation (MCLMR). Recently, such mutations were also found to be associated with familial exudative vitreoretinopathy (FEVR). Here, we report 7 novel KIF11 mutations identified by targeted gene capture in a cohort of 142 probands with FEVR who were diagnosed in our clinic between March 2015 and November 2015. These mutations were: p.L171V, c.790-2A>C, p.Q525*, p.Q842*, p.S936*, p.L983fs and p.R1025G. Phenotypic analysis revealed that all of the affected probands had advanced FEVR (stage 4 or above). Three had microcephaly, and one had chorioretinopathy, which indicated a phenotypic overlap with MCLMR. Two mutations were also found in the families of the affected probands. One parent with a p.R1025G mutation had an avascular peripheral retina and abnormal looping vessels. However, one parent with p.L983fs had normal retina, which indicated incomplete penetration of the genotype. Our results further confirmed that KIF11 is causative of FEVR in an autosomal dominant manner. We also suggest the examination of MCLMR-like features, such as microcephaly, chorioretinopathy, for patients with FEVR and wide-field fundus photography for patients with MCLMR in future practice. PMID:27212378

  7. AUTOMATED DETECTION OF HARD EXUDATES IN FUNDUS IMAGES USING IMPROVED OTSU THRESHOLDING AND SVM

    Directory of Open Access Journals (Sweden)

    Weiwei Gao

    2016-02-01

    Full Text Available One common cause of visual impairment among people of working age in the industrialized countries is Diabetic Retinopathy (DR. Automatic recognition of hard exudates (EXs which is one of DR lesions in fundus images can contribute to the diagnosis and screening of DR.The aim of this paper was to automatically detect those lesions from fundus images. At first,green channel of each original fundus image was segmented by improved Otsu thresholding based on minimum inner-cluster variance, and candidate regions of EXs were obtained. Then, we extracted features of candidate regions and selected a subset which best discriminates EXs from the retinal background by means of logistic regression (LR. The selected features were subsequently used as inputs to a SVM to get a final segmentation result of EXs in the image. Our database was composed of 120 images with variable color, brightness, and quality. 70 of them were used to train the SVM and the remaining 50 to assess the performance of the method. Using a lesion based criterion, we achieved a mean sensitivity of 95.05% and a mean positive predictive value of 95.37%. With an image-based criterion, our approach reached a 100% mean sensitivity, 90.9% mean specificity and 96.0% mean accuracy. Furthermore, the average time cost in processing an image is 8.31 seconds. These results suggest that the proposed method could be a diagnostic aid for ophthalmologists in the screening for DR.

  8. Chemical composition and functional properties of gum exudates from the trunk of the almond tree (Prunus dulcis).

    Science.gov (United States)

    Mahfoudhi, N; Chouaibi, M; Donsì, F; Ferrari, G; Hamdi, S

    2012-06-01

    The physicochemical components and functional properties of the gum exudates from the trunk of the almond tree (Prunus dulcis) have been investigated, along with the emulsification and foaming properties. The gum exudates are composed on dry weight basis by 2.45% of proteins, 0.85% of fats and 92.36% of carbohydrates. The latter consist of arabinose, xylitol, galactose and uronic acid (46.8 : 10.9 : 35.5 : 6.0 mass ratio) with traces of rhamnose, mannose and glucose. Moreover, gum exudates are rich in minerals, such as sodium, potassium, magnesium, calcium and iron. The emulsifying capacity was studied for a 20% w/w olive oil in water emulsion as a function of gum concentration (from 3% to 12% w/w in the aqueous phase) as well as pH levels (from 3.0 to 10.0). The most stable and homogeneous emulsion was prepared with an 8% w/w aqueous almond gum solution at a pH between 5.0 and 8.0. In particular, for the same formulation, the emulsion processed by high pressure homogenization (5 passes at 200 MPa) resulted to be extremely stable under accelerated ageing, exhibiting no significant change in droplet size distribution for 14 days at 55 °C. All the tested systems exhibited an extremely low foaming capacity. PMID:22701057

  9. Crop genotype and a novel symbiotic fungus influences the root endophytic colonization potential of plant growth promoting rhizobacteria.

    Science.gov (United States)

    Singh, Geeta; Singh, N; Marwaha, T S

    2009-01-01

    Effect of plant genotype on the root endophytic colonization ability of a plant growth promoting rhizobacteria (PGPR), Pseudomonas striata was undertaken in this study. Use of a lac-Z tagged P. striata strain showed that, it can exist as an endophyte and the plant genotype determines the performance of the inoculated PGPR. The cultivars of Zea mays L. (maize) and Vigna radiata L. (mung bean) tested showed differential affinity to the PGPR (P. striata) as reflected by a significant variation in the root endophytic colonization ability of P. striata. Coinoculation with a novel symbiotic fungus Piriformospora indica was found to stimulate endophytic colonization of P. striata in both maize and mungbean. The root exudates of maize and mungbean cultivars showed variations in the total sugar and amino acid contents. However, no consistent relationship was recorded between the concentrations of these metabolites and endophytic colonization of the added PGPR. PMID:23572916

  10. Biosynthesis of chlorine-containing compounds in Menispermum Dauricum root cultures

    International Nuclear Information System (INIS)

    Effects of chloride ion on production of acutumine and dechloroactumine, by Menispermum dauricum root culture, were studied. The chloride ion contents in the medium play a key role in production of both alkaloids. A medium with low chloride contents promoted production of dechloroactumine and suppressed that of acutumine. Production of the two alkaloids during the 60 days culture period was closely associated with root biomass. Both alkaloids accumulated in the roots and a relatively small proportion was exuded into the medium. The intact plant produced very little amounts of both alkaloids. On the average roots contained 22 and 75-fold more acutumine and dechloroactumine, respectively, than the intact plants. The biosythetic relationship between acutumine and dechloroactumine was studied using 13C-labeled tyrosine and 3H-labeled dechloroactumine as tracers. 13C-NMR spectra of 13C-labeled acutumine and dechloroactumine showed that the alkaloids, each composed of two molecules of tyrosine, are derived from the same biosythetic pathway. Feeding Menispermum dauricum roots, cultured in a chloride-enriched medium, with 3H-labeled dechloroactumine demonstrated that actumine is the only alkaloid metabolite of dechloroactumine. Conversion (5%) of the exogenously applied dechloroactumine, taken up by the roots, into acutumine showed that dechloroactumine is the precursor of acutumine. Incomplete conversion of dechloroactumine into acutumine suggests accumulation of the exogenously applied dechloroactumine in cell organelles and/or compartmentation of the enzymes involved in the biosynthesis of acutumine. In addition to acutumine, acutumidine and two new chlorine-containing alkaloids, named 1-epiacutumine, and 1-piacutumine, were isolated from M. Dauricum root cultures and the intact plants. Their structures were determined based on MS and 1H and 13C NMR spectra. Accumulations of these alkaloids were found to be low in the intact plant compared with the cultured roots. Crude

  11. ROOT User Workshop 2013

    CERN Document Server

    2013-01-01

    Since almost two decades, ROOT has established itself as the framework for HENP data processing and analysis. The LHC upgrade program and the new experiments being designed at CERN and elsewhere will pose even more formidable challenges in terms of data complexity and size. The new parallel and heterogeneous computing architectures that are either announced or already available will call for a deep rethinking of the code and the data structures to be exploited efficiently. This workshop, following from a successful series of such events, will allow you to learn in detail about the new ROOT 6 and will help shape the future evolution of ROOT.

  12. Na+ and Water Uptake in Relation to the Radial Reflection Coefficient of Root in Arrowleaf Saltbush Under Salt Stress

    Institute of Scientific and Technical Information of China (English)

    Xin-Fu Bai; Jian-Jun Zhu; Ping Zhang; Yan-Hua Wang; Li-Qun Yang; Lei Zhang

    2007-01-01

    The response of halophyte arrowleaf saltbush (Atriplex triangularis Willd) plants to a gradient of salt stress were investigated with hydroponically cultured seedlings. Under salt stress, both the Na+ uptake into root xylem and negative pressures in xylem vessels increased with the elevation of salinity (up to 500 mol/m3) in the root environment. However, the increment in negative pressures in root xylem far from matches the decrease in the osmotic potential of the root bathing solutions, even when the osmotic potential of xylem sap is taken into consideration. The total water potential of xylem sap in arrowleaf saltbush roots was close to the osmotic potential of root bathing solutions when the salt stress was low, but a progressively increased gap between the water potential of xylem sap and the osmotic potential of root bathing solutions was observed when the salinity in the root environment was enhanced. The maximum gap was 1.4 MPa at a salinity level of 500 mol/m3 without apparent dehydration of the tested plants. This discrepancy could not be explained with the current theories in plant physiology. The radial reflection coefficient of root in arrowleaf saltbush decreased with the enhanced salt stress was and accompanied by an increase in the Na+ uptake into xylem sap. However, the relative Na+ in xylem exudates based on the corresponding NaCl concentration in the root bathing solutions showed a tendency of decrease. The results showed that the reduction in the radial reflection coefficient of roots in the arrowleaf saltbush did not lead to a mass influx of NaCl into xylem when the radial reflection coefficient of the root was considerably small; and that arrowleaf saltbush could use small xylem pressures to counterbalance the salt stresses, either with the uptake of large amounts of salt, or with the development of xylem pressures dangerously negative. This strategy could be one of the mechanisms behind the high resistance of arrowleaf saltbush plants to salt

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

    Science.gov (United States)

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

    2016-04-01

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

  14. Genetic association among root morphology, root quality and root yield in ashwagandha (Withania somnifera

    Directory of Open Access Journals (Sweden)

    Kumar Ramesh R.

    2011-01-01

    Full Text Available Ashwagandha (Withania somnifera is a dryland medicinal crop and roots are used as valuable drug in traditional systems of medicine. Morphological variants (morphotypes and the parental populations were evaluated for root - morphometric, quality and yield traits to study genetic association among them. Root morphometric traits (root length, root diameter, number of secondary roots/ plant and crude fiber content exhibited strong association among them and showed significant positive genotypic correlation with yield. Starch-fiber ratio (SFR, determinant of brittle root texture showed strong negative association with root yield. The total alkaloid content had positive genotypic correlation with root yield. So genetic upgradation should aim at optimum balance between two divergent groups of traits i.e. root yield traits (root morphometric traits and crude fiber content and root textural quality traits (starch content and SFR to develop superior genotypes with better yield and quality.

  15. Simultaneous decay of contact-angle and surface-tension during the rehydration of air-dried root mucilage

    Science.gov (United States)

    Arye, Gilboa; Chen, Fengxian

    2016-04-01

    Plants can extract or exude water and solutes at their root surface. Among the root exudates, the mucilage exhibits a surfactant like properties - depressing the surface-tension (ST, mN/m) at the water-air interface. The amphipathic nature of some of the mucilage molecules (e.g. lipids) is thought to be the reason for its surfactant like behavior. As the rhizosphere dries out, re-orientation and/or re-configuration of amphipathic molecules at the solid-air interface, may impart hydrophobic nature to the rhizosphere. Our current knowledge on the ST of natural and/or model root mucilage is based on measurements of the equilibrium ST. However, adsorption of amphipathic molecules at the water-air interface is not reached instantaneously. The hydrophobic nature of the rhizosphere was deduced from the initial advancing CA, commonly calculated from the first few milliseconds up to few seconds (depending on the method employed). We hypothesized that during the rehydration of the root mucilage; both quantities are dynamic. Processes such as water absorbance and dissolution, may vary the interfacial tensions as a function of time. Consequently, simultaneous reduction of both CA and ST as a function of time can be expected. The main objective of this study was to characterize and quantify the extent, persistency and dynamic of the CA and ST during rehydration of air-dried root mucilage. The study was involved with measurements of dynamic and equilibrium ST using the pedant drop or Wilhelmy plate method, respectively. Glass slides were coated with naturally occurring or model root mucilage and the CA of a sessile drop was measured optically, as a function of time. The results were analyzed based on the Young-Dupré and Young-Laplace equations, from which the simultaneous decay of CA and ST was deduced. The implication for the wettability and water flow in the rhizosphere will be discussed.

  16. Results of Intravitreal Ranibizumab Treatment for Exudative Age-Related Macular Degeneration

    Directory of Open Access Journals (Sweden)

    Umut Karaca

    2012-01-01

    Full Text Available Pur po se: To evaluate the efficacy and safety of intravitreal ranibizumab injection for exudative age-related macular degeneration. Ma te ri al and Met hod: In this study, we included forty-eight eyes of 43 age-related macular degeneration patients followed for at least twelve months. Mean age was 73.65±8.93 years and mean follow-up time was 14.2 months. All patients received three consecutive monthly intravitreal ranibizumab injections and then were followed up with clinical examination and optic coherence tomography monthly. Re-injection was executed as needed. Re sults: Twenty patients were male (46.5% and twenty-three patients were female (53.5%. The average number of ranibizumab injection was 3.7 (3-7 per eye. Twenty-six lesions (54.2% were classic (predominantly and minimally and twenty-two (45.8% were occult. Mean best-corrected visual acuity was 46.8 letters with ETDRS chart at the initial examination and 55.5 letters at twelfth month. Mean central foveal thickness decreased from 320 microns to 269 microns. There was a statistically significant improvement in visual acuity and central foveal thickness. On the other hand, this improvement was not significant between lesion types. During follow-up, there were no systemic or serious ocular complications determined. Dis cus si on: Intravitreal ranibizumab injection is safe and effective, both anatomically and functionally, for age-related macular degeneration. (Turk J Ophthalmol 2012; 42: 25-9

  17. Strontium-90 brachytherapy for exudative, age related macular degeneration: a pilot study

    International Nuclear Information System (INIS)

    ARMD is the leading cause of visual loss in the 55 and older population. Recent data suggests that low dose external beam irradiation seems to have a beneficial effect in stabilizing the central visual acuity, by arresting or delaying the progression of the central scotoma. The authors decided to use a newly designed Strontium-90 Macular Applicator in a pilot study to ascertain its effectiveness in controlling exudative, age related macular degeneration. Two groups of 10 patients each were treated. The first group received a total dose of 10 Gy at 1.5 mm depth in a total time of 4 minutes and 20 seconds, fractionated in 4 applications of 1 minut